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Article
A new baseline of organic carbon stock in European agricultural soils using a modelling approach
Abstract
Proposed European policy in the agricultural sector will place higher emphasis on soil organic carbon (SOC), both as an indicator of soil quality and as a means to offset CO2 emissions through soil carbon (C) sequestration. Despite detailed national SOC datasets in several European Union (EU) Member States, a consistent C stock estimation at EU scale remains problematic. Data are often not directly comparable, different methods have been used to obtain values (e.g. sampling, laboratory analysis, etc.) and access may be restricted. Therefore, any evolution of EU policies on C accounting and sequestration may be constrained by a lack of an accurate SOC estimation and the availability of tools to carry out scenario analysis, especially for agricultural soils. In this context, a comprehensive model platform was established at a pan-European scale (EU + Serbia, Bosnia and Herzegovina, Croatia, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) using the agro-ecosystem SOC model CENTURY. Almost 164000 combinations of soil-climate-land use were computed, including the main arable crops, orchards and pasture. The model was implemented with the main management practices (e.g. irrigation, mineral and organic fertilization, tillage, etc.) derived from official statistics. The model results were tested against inventories from the European Environment and Observation Network (EIONET) and approximately 20,000 soil samples from the 2009 LUCAS survey, a monitoring project aiming at producing the first coherent, comprehensive and harmonized top-soil dataset of the EU based on harmonized sampling and analytical methods. The CENTURY model estimation of the current 0-30 cm SOC stock of agricultural soils was 17.63 Gt; the model uncertainty estimation was below 36% in half of the NUTS2 regions considered. The model predicted an overall increase of this pool according to different climate-emission scenarios up to 2100, with C loss in the south and east of the area (involving 30% of the whole simulated agricultural land) compensated by a gain in central and northern regions. Generally, higher soil respiration was offset by higher C input as a consequence of increased CO2 atmospheric concentration and favourable crop growing conditions, especially in northern Europe. Considering the importance of SOC in future EU policies, this platform of simulation appears to be a very promising tool to orient future policymaking decisions. This article is protected by copyright. All rights reserved.
... Several approaches to estimating SOC storage potential have been developed according to the observed maximum SOC level (Lilly and Baggaley, 2013;Pan et al., 2003), SOC saturation deficit approach (Angers et al., 2011;Chen et al., 2018;Hassink, 1997;Wiesmeier et al., 2014), and mechanistic simulation models (Lugato et al., 2014). Among these methods, the widely used concept of C saturation deficit is a rapid and economic method to test over a large variety of soil properties for estimating soil C sequestration (Dignac et al., 2017). ...
... However, due to fact that the saturation concept is associated with soil fine fraction (Hassink, 1997), large uncertainties could emerge when a significant percentage of SOC is stored in the coarse fraction Chen et al., 2019). Besides, the mechanistic simulation models for SOC sequestration/storage estimation were usually employed under the experimental scenario of different soil management practices (e.g., fertilization) applied (Zhang et al., 2015), and the theoretical SOC estimates highly relied on massive input variables and parameters (Lugato et al., 2014). Moreover, the theoretical SOC sequestration potential might not be reached due to limited access to available resources (e.g., fertilizer or water) under certain pedoclimatic conditions Chenu et al., 2019). ...
... Optimal strategies for achieving the SOC sequestration potential by optimizing the combinations of cropping systems, straw return and organic inputs under different cropland carbon landscape systems based on current cropping systems and soil management practices. 2017; Lugato et al., 2014), which is usually limited by available site-based experiments, detailed soil management options, and adaptability extending local to other areas . Certainly, as the estimated SOC storage potential was based on constant SOC baseline and current management practices, it could be biased when SOC baseline trend increases (potential overestimation) or new SOC aggrading techniques are adopted (potential underestimation). ...
Soil organic carbon (SOC) is receiving increasing attention due to its large storage potential in global carbon cycles and its great importance to soil fertility, agricultural production, and ecosystem services. The increases of SOC storage and reliable estimation of its potential are essential for evaluating the soil sustainability and climate change adaptation under intensive cultivation. In this work, a data-driven approach combining mixture clustering and Random Forest models was proposed to estimate the SOC storage potential of cropland topsoil and its controlling factors in East China. The carbon landscapes systems (CLSs) were delineated using a mixture clustering model by combining the climatic condition, soil properties, cropping systems, and soil management practices. The SOC storage potentials with 95 % confidence intervals at 250 m spatial resolution were estimated as the difference between the current SOC stock and empirically maximum SOC stock at basic (75 %), intermediate (85 %), and ambitious (95 %) expectation objectives for each CLS. The SOC storage potential increased with the increasing of expectation objective settings, with the averaged levels of 13.1, 20.8, and 35.5 t C ha⁻¹ at 75 %, 85 %, and 95 % percentile objectives, respectively. The variable importance from Random Forest indicated that the cropping systems and soil management practices were the unignorable factors controlling the SOC storage potential beyond the climatic conditions and soil properties. Moreover, the shifts of human-induced controlling factors, e.g., cropping systems, also indicated their capability of SOC sequestration potential for partly achieving the “4p1000” initiative (annual growth rate of 0.4 % carbon stocks in the first 30 cm of topsoil). The currently optimal soil management practices for achieving the SOC sequestration potential was the combination of rice-based cropping systems, straw return, and organic fertilizer applied. The data-driven approach coupling with CLSs improved our understanding of the controlling factors on SOC storage potential at regional level with homogenous conditions, enabling evidence-based decision making in promoting carbon sequestration by adopting locally feasible soil management practices.
... For each catchment *1300 model runs were performed to simulate the sediment yield for each possible combination of the WaTEM/SEDEM coefficients. Lugato et al. (2014) estimates the current SOC stock in the plough layer (0-30 cm) of European Union agricultural soils as 17.63 Pg. A few studies have coupled erosion/transport models and SOC models of different complexity (Van Oost et al. 2005) to disentangle all these interactions, but the scale has generally been limited to individual landscapes and watersheds or small regions (Nadeu et al. 2015). ...
... However, at large regional/continental scales, such as for the EU, the impact of soil erosion on overall SOC balance is still unknown due to the lack of high resolution soil erosion rates as input for process-based biogeochemical models. To estimate the magnitude of the lateral C fluxes induced by soil erosion at these large scales, we coupled a new high-resolution (100 m 2 ) dataset of soil erosion (Panagos et al. 2015a) based on RUSLE, with the biogeochemical CENTURY model running for European agricultural soils on a grid of 1 km (Lugato et al. 2014). ...
... Soil temperature and moisture, soil texture and cultivation practices act as modifying factors on potential decomposition rate constants. Using CENTURY model, Lugato et al. (2014) created a consistent SOC stock baseline for the European agricultural soils (including arable, grassland and orchard land use), covering a total of about 187 million hectares (or 1.87 million km 2 ) in EU. Coupling the process-based biogeochemistry model CENTURY to the RUSLE2015 erosion model we have developed a model framework for carbon-erosion integration. ...
We present the developments on soil erosion modelling at European scale to respond to the policy needs. The Joint Research Centre (JRC) of the European Commission has developed the European Soil Erosion Modelling Platform (EUSEMP) to support the agro-environmental policies in the European Union (EU). The major component of EUSEMP is an hybrid soil erosion model named RUSLE2015 (RUSLE-based) to estimate soil loss by water erosion. The model runs with updated input layers (years: 2000, 2010 and 2016) and provides baselines for evaluating the current status of agricultural soils in the EU, evaluating the impact of agri-environmental policies on land management and making projections of soil loss by water erosion in 2050. In addition, EUSEMP includes also the Revised Wind Erosion Equation (RWEQ) to access wind erosion in EU arable lands and another component to access soil loss due to harvesting crops. Another component of EUSEMP is the sediment delivery model WaTEM/SEDEM to estimate net soil loss. Finally, the erosion models are coupled with the biogeochemical CENTURY model to estimate soil organic carbon losses by water erosion. EUSEMP targets to integrate the sediments transfer datasets with soil pollution data (e.g. mercury, copper) and nutrient losses (e.g. phoshorus).
... Dominant topsoil (0-30 cm) and subsoil (30-120 cm) properties were calculated for each 1 × 1 km grid cell (hereafter referred to as soil grids) from the underlying soil datasets: the European Soil Bureau Database (ESDB, version 2.0, https://esdac.jrc.ec.europa.eu), the Database of Hydraulic Properties of European Soils (Wösten et al., 1999), and the Map of organic carbon content in the topsoil (Lugato et al., 2014). A total of 13 soil properties as in Balkovič et al. (2013) were used. ...
... The initial SOC concentration and soil C in the passive pool, followed by the particle size distribution, turned out as the most influential soil inputs in our study (Fig. 2). Indeed, soil C concentration and passive C pool are closely associated with land use and land use change activities (Eggleston et al., 2006) and they are the key soil properties for biophysical carbon modelling (Basso et al., 2011;Hashimoto et al., 2011;Lugato et al., 2014). As also demonstrated by our UA results, a proper initial SOC and passive C concentration is an essential condition for quantification of land use impacts by biophysical models (e.g. ...
... As also demonstrated by our UA results, a proper initial SOC and passive C concentration is an essential condition for quantification of land use impacts by biophysical models (e.g. Lugato et al., 2014). For example, at the Trutnov site, soils initially poor in humus sequestered C under all initial soil conditions except for those with a sandy texture, whereas soils initially richer in humus sequestered C only when medium-fine or finer, and only when dominated by the passive C pool (Fig. A6). ...
Regional monitoring, reporting and verification of soil organic carbon change occurring in managed cropland are indispensable to support carbon-related policies. Rapidly evolving gridded agronomic models can facilitate these efforts throughout Europe. However, their performance in modelling soil carbon dynamics at regional scale is yet unexplored. Importantly, as such models are often driven by large-scale inputs, they need to be benchmarked against field experiments. We elucidate the level of detail that needs to be incorporated in gridded models to robustly estimate regional soil carbon dynamics in managed cropland, testing the approach for regions in the Czech Republic. We first calibrated the biogeochemical Environmental Policy Integrated Climate (EPIC) model against long-term experiments. Subsequently, we examined the EPIC model within a top-down gridded modelling framework constructed for European agricultural soils from Europe-wide datasets and regional land-use statistics. We explored the top-down, as opposed to a bottom-up, modelling approach for reporting agronomically relevant and verifiable soil carbon dynamics. In comparison with a no-input baseline, the regional EPIC model suggested soil carbon changes (~0.1–0.5 Mg C ha⁻¹ y⁻¹) consistent with empirical-based studies for all studied agricultural practices. However, inaccurate soil information, crop management inputs, or inappropriate model calibration may undermine regional modelling of cropland management effect on carbon since each of the three components carry uncertainty (~0.5–1.5 Mg C ha⁻¹ y⁻¹) that is substantially larger than the actual effect of agricultural practices relative to the no-input baseline. Besides, inaccurate soil data obtained from the background datasets biased the simulated carbon trends compared to observations, thus hampering the model's verifiability at the locations of field experiments. Encouragingly, the top-down agricultural management derived from regional land-use statistics proved suitable for the estimation of soil carbon dynamics consistently with actual field practices. Despite sensitivity to biophysical parameters, we found a robust scalability of the soil organic carbon routine for various climatic regions and soil types represented in the Czech experiments. The model performed better than the tier 1 methodology of the Intergovernmental Panel on Climate Change, which indicates a great potential for improved carbon change modelling over larger political regions.
... The Roadmap to a Resource Efficient Europe (EC, 2011), established the goal of enhancing current SOC levels in the EU by 2020 (Lugato et al., 2014). In addition, under Common Agricultural Policy (CAP), farmers are called up to maintain the agro-ecosystem by rural development measures coupled with the environmentally sustainable farming practices promotion. ...
... In addition, under Common Agricultural Policy (CAP), farmers are called up to maintain the agro-ecosystem by rural development measures coupled with the environmentally sustainable farming practices promotion. Therefore, farmers must achieve soil erosion protection, soil structure maintenance and soil OM levels under the EU cross-compliance scheme (Lugato et al., 2014). ...
... Permanent crops, such as vineyard, olive and orchard contribute for only 3% of the total SOC-S in Europe (Lugato et al., 2014), and these land uses are mainly located in Mediterranean areas (Spain, Italy and France) where natural vegetation was previously present, resulting in an extremely complex, expensive and non-environmentally friendly crop management. Consequently, farmers and politicians must avoid converting natural areas to agricultural land before an exhaustive study about the possible effects has been completed (ESDAC, 2018). ...
The knowledge about land management effects on soil capacity to store carbon is necessary to planning effective strategies by managers and decision-makers. In this study we analyzed the land use change (LUC) effects on soil organic carbon stocks (SOC-S) for long term in the Sardinia region - Italy (Mediterranean area).
Throughout the 20th century, the studied area has undergone different LUC. The first LUC was in 1938, from forest to agricultural land under three different uses: vineyards, hay crop and pasture, later (1966) some of this agricultural land were abandoned to seminatural ecosystem (second LUC). The different LUC affected to SOC-S causing decarbonization, carbonization and recarbonization processes along the soil profile.
The different land uses studied chronologically were: i) natural forest - cork oak forest (Cof), ii) tilled vineyard (Tv), iii) no tilled grassed vineyard (Ntgv), iv) hay crop (Hc), v) pasture - silvopastoral and silvoarable practices (P), and vi) former vineyard - vineyards abandoned and naturally revegetated (Fv). The first LUC (Cof to Tv, Ntgv, Hc and P) caused 5.1% and 37.5% reduction on SOC-S for Tv and Ntgv (soil decarbonization), however, the SOC-S increased 47.1% and 51.3% for Hc and P respectively (soil carbonization). The second LUC (Tv and Ntgv to Fv) increased the SOC-S on average 66.3% (soil recarbonization). In general, these effects were observed principally in depth.
This study shows the importance of land use and LUC with respect to SOC-S, and that the human action can degrade and/or regenerate the soil, affecting to soil functions. Consequently, is necessity to promote good environmental practices to improve the soil functions and to reduce the greenhouse gases (ecosystem services). On the presumption that the SOC sequestration through of agricultural management can reduced the atmospheric CO2 concentration (4p1000 target in the XXI Conference of the Parties – Paris, 2015). Therefore, the soils regeneration via carbonization and/or recarbonization is an opportunity to prevent the climate change.
... It is often highly depleted compared with that of soils under natural vegetation such as forest or grassland (Wiesmeier et al., 2012). Therefore including cover crops (also known as catch crops or intercrops) in the rotation is gaining increasing interest as a measure to increase the soil organic carbon (SOC) pool (Lugato et al., 2014). ...
... A frequently applied model is the Rothamsted Carbon Model (RothC) which was specifically designed to simulate SOC dynamics in temperate cropland and grassland soils (Jenkinson and Rayner, 1977;Coleman et al., 1997;Coleman and Jenkinson, 1999;Falloon and Smith, 2002). Several modelling approaches were conducted to simulate regional or global development of agricultural SOC stocks (Smith et al., 2005a;Zaehle et al., 2007;Alvaro-Fuentes et al., 2012;Mondini et al., 2012;Lugato et al., 2014;Zhong and Xu, 2014). However, these SOC projections were often based on simple estimations of important input variables or legacy data with a relatively low spatial resolution. ...
... Future projections of the development of C inputs in agricultural soils are even more challenging due to overlapping implications of crop and land use management, future trend of crop breeding and technology and climate change. In several SOC modelling studies it was assumed that the development of agricultural C inputs are simply related to NPP development, which can be simulated by vegetation models (Cramer et al., 2001;Sitch et al., 2003;Jones et al., 2005b;Smith et al., 2005a;Zaehle et al., 2007;Alvaro-Fuentes et al., 2012;Lugato et al., 2014). However, such an approach neglects the fact that the C input in agricultural soils is controlled by various factors including management practices. ...
Organischer Bodenkohlenstoff (SOC) ist der größte terrestrische Kohlenstoff (C)-Pool, welcher ein Vielfaches des gesamten atmosphären C speichert. Landwirtschaftliche Nutzung von Böden hat einen starken Einfluß auf diesen Speicher und so auch auf C-Flüsse zwischen Atmosphäre und Biosphäre. Historsich haben Landnutzungsänderungen zu starken CO2-Emissionen aus Böden geführt, was auch einen signifikanten Einfluß auf die globale Erwärmung hatte. Diese kumulative Habilitationsschrift fokusiert auf zwei Haupteinflüsse des Menschen auf SOC: Landnutzung und globale Erwärmung durch Treibhausgasemisionen. Beide sind mit der globalen Ausbreitung des Menschen und der sprunghaften Entwicklung dessen Aktivität auf Erden stark angestiegen und werden somit als spezifisch für das „Anthropozän“ erachtet, welches hier als Synonym für jene Periode in der Weltgeschichte benutzt wird, in der menschliche Aktivität irreversible Spuren hinterlassen hat.. Durch die große Bedeutung von SOC und dessen Management für den Klimawandel, aber auch für Bodenfruchtbarkeit und Resilienz von Ökosystemen, ist es wichtig zu verstehen, i) welche Management-Optionen SOC erhalten und vermehren können ii) welche Mechanismen zu dessen Verlust und Stabilisierung führen, iii) wie die globale Nettoprimärproduktion auf möglichst nachhaltige und klimafreundliche Weise genutzt werden kann und iv) wie die globale Erwärmung C-Vorräte im Boden beeinflussen wird. Zusammen mit einigen methodischen Aspekten, welche zu einer verbesserten Messung, Berechnung und Modellierung von SOC beitragen sollen, bilden jene Themenomplexe den wissenschaftlichen Fokus dieser Arbeit.
... Highest SOC stocks were simulated for forests, followed by grassland and shrubs. This matches estimates by other studies [38,39,77], although our estimates for grassland (11 Gt) are somewhat higher than those by Yigini and Panagos [38] (6.7 Gt). SOC stocks for fruit trees, olive groves and vineyard were estimated at around 60 t/ha on average across Europe, while the average SOC stocks for arable land across Europe was estimated at 43 t/ha or 5 Gt, which is lower than e.g., Lugato et al. [39] Figures S12-S15). ...
... This matches estimates by other studies [38,39,77], although our estimates for grassland (11 Gt) are somewhat higher than those by Yigini and Panagos [38] (6.7 Gt). SOC stocks for fruit trees, olive groves and vineyard were estimated at around 60 t/ha on average across Europe, while the average SOC stocks for arable land across Europe was estimated at 43 t/ha or 5 Gt, which is lower than e.g., Lugato et al. [39] Figures S12-S15). However, the SOC stock map based on the soil profile analytical database for Europe (SPADE; [77]; Figure S15) Calibration results for SOC stocks for the three countries and Crete for which the model was calibrated are shown in Table 4. Overall, results were close to the observed data, derived from the LUCAS database. ...
Healthy soils are fundamental for sustainable agriculture. Soil Improving Cropping Systems (SICS) aim to make land use and food production more sustainable. To evaluate the effect of SICS at EU scale, a modelling approach was taken. This study simulated the effects of SICS on two principal indicators of soil health (Soil Organic Carbon stocks) and land degradation (soil erosion) across Europe using the spatially explicit PESERA model. Four scenarios with varying levels and combinations of cover crops, mulching, soil compaction alleviation and minimum tillage were implemented and simulated until 2050. Results showed that while in the scenario without SICS, erosion slightly increased on average across Europe, it significantly decreased in the scenario with the highest level of SICS applied, especially in the cropping areas in the central European Loess Belt. Regarding SOC stocks, the simulations show a substantial decrease for the scenario without SICS and a slight overall decrease for the medium level scenario and the scenario with a mix of high, medium and no SICS. The scenario with a high level of SICS implementation showed an overall increase in SOC stocks across Europe. Potential future improvements include incorporating dynamic land use, climate change and an optimal spatial allocation of SICS.
... Grasslands in England and Wales are used to feed dairy cows, beef cattle, and sheep and effective grass management is a key determinant of farm income on most livestock farms. Grasslands also provide environmental benefits such as carbon storage, biodiversity maintenance and erosion control [1][2][3]. In the context of climate change, there is a need to determine the efficacy of adaptation strategies to increase the productivity and resilience of grass production, while also enhancing the essential ecosystem services they provide [4][5][6]. ...
... The rate constants (k rpm, k dpm ) in Equation (1) can be determined from the soil temperature (T; • C), the actual moisture content (θ), and the moisture contents at permanent wilting point (θ PWP ) and field capacity (θ FC ) according to the Arrhenius relationship (Equations (2) and (3); [30,31]). ...
This study examines the effectiveness of a model called LINGRA-N-Plus to simulate the interaction of climate, soil and management on the green leaf and total dry matter yields of ryegrass in England and Wales. The LINGRA-N-Plus model includes modifications of the LINGRA-N model such as temperature- and moisture-dependent soil nitrogen mineralization and differential partitioning to leaves and stems with thermal time from the last harvest. The resulting model was calibrated against the green leaf and total grass yields from a harvest interval x nitrogen application experiment described by Wilman et al. (1976). When the LINGRA-N-Plus model was validated against total grass yields from nitrogen experiments at ten sites described by Morrison et al. (1980), its modelling efficiency improved greatly compared to the original LINGRA-N. High predicted yields, at zero nitrogen application, were related to soils with a high initial nitrogen content. The lowest predicted yields occurred at sites with low rainfall and shallow rooting depth; mitigating the effect of drought at such sites increased yields by up to 4 t ha−1. The results highlight the usefulness of grass models, such as LINGRA-N-Plus, to explore the combined effects of climate, soil, and management, like nitrogen application, and harvest intervals on grass productivity.
... In addition to this, we need to keep in mind that the SOC reduction is one of the eight soil threats identified in the European Union (EU) Thematic Strategy for Soil Protection (EC, 2006(EC, , 2012, and therefore one of the most important aims is to maintain and improve the SOC stock (SOC-S) throughout the EU countries. The Roadmap to a Resource Efficient Europe (EC, 2011), established the goal of enhancing current SOC levels in the EU by 2020 (Lugato et al., 2014). Also, under Common Agricultural Policy (CAP), farmers are called up to maintain the agroecosystem by rural development measures coupled with the environmentally sustainable farming practices promotion. ...
... Also, under Common Agricultural Policy (CAP), farmers are called up to maintain the agroecosystem by rural development measures coupled with the environmentally sustainable farming practices promotion. Therefore, farmers must achieve soil erosion protection, soil structure maintenance and soil OM levels under the EU cross-compliance scheme (Lugato et al., 2014). Under this scenario, the soil carbon studies will be linked to factors such as: soil health, ecosystem services and, derived from this, economic implications. ...
The spatial distribution of soil organic carbon (SOC) is essential to estimate the SOC reserves. Therefore, the soils ability to store organic carbon is a key factor for climate regulation and for other soil functions. The soil management and the topographic position play an important role in SOC variation, especially when the landscape is not uniform (Mediterranean areas). Many researches have explored the SOC distribution according to topographic position in hillsides for long-term, but very few studies have focused on the short term. Therefore, it is necessary to know, the changes that taking place in the soil due to land management change (LMC) in these irregular surfaces for sustainable agricultural production and its implications on climate change regulation.
This study aims to assess the influence of topographic position and LMC on SOC stock (SOC-S) in Mediterranean olive groves (OG) soils in short term (2 years). In this line, three experimental plots were selected in three topographical position (summit - S, backslope - B and toeslope - T). In these plots, the land management was modified from conventional tillage (CT) to no tillage (NT) with application of pruned olive branch chippings branches and vegetation cover (spontaneous vegetation) in the OG streets.
The studied soils did not show important changes due to LMC in their physical properties for short term, in addition, these soils were characterized by low organic matter content (<1.2%). LMC caused a SOC reduction in surface, and a SOC increase in the Bw horizon. The N concentrations showed a similar trend to SOC and the C:N ratios were highly variable (4.37: C horizon-NT-S; 13.45 Bw/C horizon -CT-B). Normally, the SOC-S concentrations decreasing in depth. LMC for two years showed soil carbonization (S and T position) and decarbonization (B position) processes. The SOC-S increased 1.88 Mg ha⁻¹ y⁻¹ and 0.47 Mg ha⁻¹ y⁻¹ for S and T topographic position respectively, however the SOC-S decreased in B position 5.27 Mg ha⁻¹ y⁻¹. Therefore, LMC has a positive effect on soil carbon reserves in S and T position, conversely in B position, this effect was negative.
... There is no unique combination of these parameters to determine the exact localization for vineyard cultivation since grapes often need site-specific conditions. Nevertheless, the integration of land use, Topography (traditionally slope, aspect, and elevation) [16], meteorological conditions (quantity of rain, temperature, and period of drought) [17], soil type (land capability classification, organic content, pH, acidity, and texture) [18], and energy (solar radiation) [19] have all considerable impacts on grapevine production and shape the terroir [13]. Therefore, a proper land suitability analysis for vineyard plantations should consider at least some of the abovementioned data and define a method of integrating these spatial layers with multicriteria analysis. ...
... Obviously, the Land Capability Classification (LCC) is extremely important for this analysis [60][61][62]. It includes all the chemical and physical soil properties that can influence the use of soil for different types of production activities [18]. For vineyard plantations, LCC should be interpreted with relative importance. ...
The grapevine, so-called Vitis vinifera L., is one of the most diffuse perennial crop plantations in the world due to a flourishing market that shaped the landscape and the societal values. Turkey has been a historical vine producer, counting on an overall vineyard extension of 550,000 hectares. Besides, Turkey has some favorable pre-requisites to be one of the most fertile lands for vineyard production: variegated topography, rich soil diversity, heterogeneous morphology, and several micro-climatic conditions. However, establishing a flourishing and fully productive vineyard requires many years, and therefore, the selection and management of sites should be considered with great attention. Within this work, a first land suitability analysis for vineyard production has been established for the entire metropolitan area of Izmir according to the most scientifically-agreed criteria: elevation, slope, aspect, land capability, and solar radiation. These criteria were superimposed through spatial overlay analysis using Esri ArcGIS (ver.10.8) and evaluated using the Principal Component Analysis technique. The first three bands were then extracted to define the most suitable areas for vineyard production in Izmir. The final layer has been used to define which areas can be considered for future strategic expansion and management. The discussion focuses on the Kozak plateau, where a new policy of vineyard plantation will be promoted with techniques that aim to maintain and revalorize the traditional vineyard landscapes and conserve traditional methods and practices that have evolved with the cultural values of the villagers and producers.
... The possibility of restoring carbon losses due to human activities has also been extensively investigated (Stockmann et al. 2013;Sanderman et al. 2017). Additionally, regional to continental assessments are being conducted to estimate the soil carbon sequestration potential of soils (Lugato et al. 2014a(Lugato et al. , 2014b. Data-driven approaches (Don et al. 2011) and process based models (Shirato 2020) have been used with this objective. ...
... Conversely, potential carbon sequestration estimations using simulation models like Century (i.e. Lugato et al. 2014aLugato et al. , 2014b are usually restricted to the surface soil layer (0-20 cm) and account for total SOC and not for the stabilised fraction. Nevertheless, process based model estimations can be validated against local data. ...
Estimates of soil carbon sequestration potential can help identify areas where appropriate use and management practices can be applied to convert them into carbon sinks. We estimated the carbon capacity of Pampean soils using previously developed models and compared the results with a local model developed by simultaneous quantile regression. We also modelled the effects of the factors controlling the carbon saturation deficit using artificial neural networks and mapped the topsoil and subsoil saturation deficit of the region. Data from a soil survey, in which 296 sites were sampled to 1 m depth, were used. Paired sites in grassland, cropland and lowland areas were selected. The total organic carbon was measured, and the proportion stabilised in the clay + silt (<20 µm) fraction was estimated. The saturation deficit could be predicted (R2 = 0.78) by neural networks and was greater in cropland, followed by lowland and then grassland. It was higher in fine textured soils, in soil surface layers and in humid and colder environments. The saturation deficit of the region is 8.8 Gt carbon (average 196 Mg C ha–1), approximately double the current organic carbon content of the region, indicating that there is considerable room for carbon sequestration in the Pampas. Efforts to increase soil carbon levels must focus on the finely textured soils in the humid part of the region.
... Nowadays, the intensive agriculture frequently results in a significant soil degradation and soil carbon depletion (Plaza-Bonilla et al. 2015). More recently, European policy in the agricultural sector has placed more emphasis on soil organic carbon, as an indicator for both soil quality and as a means to offset CO 2 emissions through soil carbon sequestration (Lugato et al. 2014). Integrated nutrient management is a judicious use of organic and inorganic sources of nutrient to crop fields for sustaining and maintaining both of soil fertility and productivity (Wailare and Kesarwani, 2017). ...
... Few countries have such monitoring schemes. The European Union (EU) started around 10 years ago with a Pan-European monitoring network to improve sustainable farming solutions and monitor soil pollution (Ballabio et al., 2014;Lugato et al., 2014). ...
Background
Legacy data are unique occasions for estimating soil organic carbon (SOC) concentration changes and spatial variability, but their use can pose limitations due to the sampling schemes adopted and improvements may be needed in the analysis methodologies. When SOC changes is estimated with legacy data, the use of soil samples collected in different plots (i.e., non-aligned data) may lead to biased results. In the present work, N=302 georeferenced soil samples were selected from a regional (Sicily, south of Italy) soil database. An operational sampling approach was developed to spot SOC concentration changes from 1994 to 2017 in the same plots at the 0-30 cm soil depth and tested.
Results
The measurements were conducted after computing the minimum number of samples needed to have a reliable estimate of SOC variation after 23 years. By applying an effect size based methodology, 30 out of 302 sites were resampled in 2017 to achieve a power of 80%, and an a=0.05.
A Wilcoxon test applied to the variation of SOC from 1994 to 2017 suggested that there was not a statistical difference in SOC concentration after 23 years (Z = -0.556; 2-tailed asymptotic significance = 0.578). In particular, only 40% of resampled sites showed a higher SOC concentration than in 2017.
Conclusions
This finding contrasts with a previous SOC concentration increase that was found in 2008 (75.8% increase when estimated as differences of 2 models built with non-aligned data), when compared to 1994 observed data (Z = -9.119; 2-tailed asymptotic significance < 0.001).
Such a result implies that the use of legacy data to estimate SOC concentration dynamics requires soil resampling in the same locations to overcome the stochastic model errors. Further experiment is needed to identify the percentage of the sites to resample in order to align two legacy datasets in the same area.
... The "4 per mill" initiative launched at the 2015 United Nations Climate Change Conference in Paris aims at increasing global SOC stocks in 0-40 cm depth by annually 4‰. With an estimated SOC stock of 17.6 Gt C, corresponding to 64.5 Gt CO2 (Lugato et al. 2014b), an annual increase by 4‰ would be 260 Mt CO2 annually. However, scenarios mixing different management options in Bavaria (Germany) including cover cropping, improved crop rotation, organic farming, agroforestry and conversion of arable land to grassland revealed that the potential for Bavaria would at maximum rather be around 1‰ of present stocks (Wiesmeier et al. 2020). ...
The management of forests, cropland and grassland impacts on the amount of greenhouse gases in the atmosphere. This is due to the fact that the way habitats such as forests, peatlands or grasslands are used determines whether they are net sources of greenhouse gases or natural carbon sinks which draw down CO2 from the atmosphere and store it in the form of carbon in plants and soils. Sustainable forest management, forest restoration and preservation, or conservation and restoration of organic soils under cropland and grassland are among measures contributing to the expansion of the EU's natural carbon storages, allowing them to fulfill their important functions in the climate system and promoting climate change adaptation. Moreover, they will help to safeguard biodiversity – a key objective of the EU Biodiversity Strategy.
In a brief analysis for Greenpeace Germany, Oeko-Institut discusses options for a target for natural carbon sinks in the European Union. In addition to the potential for carbon sequestration, the study analyses the contributions as well as the conflicts arising from an enhancement of carbon sinks with respect to the EU strategies for the expansion of renewable energies, climate change adaptation and biodiversity conservation respectively.
... Land use is the first planning step if the biomass feedstock (all or a part of it) derives from dedicated crops [157,158]. Decision making must consider challenges [159] for improving soil quality, maintaining, and increasing soil carbon [160], rehabilitating degraded land [161][162][163] and avoiding land use change [164,165] [171], to integrate these policies in biomass supply chains for advanced biofuels [172]. ...
Advanced biofuels are among the available options to decarbonise transport in the short to medium term especially for aviation, marine and heavy-duty vehicles that lack immediate alternatives. Their production and market uptake, however, is still very low due to several challenges arising across their value chain. So far policy has established targets and monitoring frameworks for low carbon fuels and improved engine erformance but has not yet been sufficient to facilitate their effective market uptake. Their market roll-out must be immediate if the 2030 targets are to be met. Analysis in this paper reiterates that the future deployment of these fuels, in market shares that can lead to the desired decarbonisation levels, still depends largely on the integration of tailored policy interventions that can overcome challenges and improve upstream and downstream performance.
The work presented aims to i) inform on policy relevant challenges that restrict the flexible, reliable and costefficient market uptake of sustainable advanced biofuels for transport, and ii) highlight policy interventions that, have strong potential to overcome the challenges and are relevant to current policy, Green Deal and the Sustainable Development Goals (SDGs).
... Gt C on the forest floors and 21.4-22.7 Gt C in the mineral and peat soils to a depth of 1 m in European forests. The topsoil SOC values for agricultural soils across Europe were determined to range between 40 and 250 t C ha −1 [Lugato et al., 2013]. The highest SOC values were found in Ireland, the UK, the Netherlands, and Finland, all of which had values of >250 t C ha −1 and correspond to peatland areas. ...
Soil is a global resource that has the capacity to contain large amounts of organic carbon. In fact, soils contain more carbon than plants and the atmosphere combined. However, in recent decades human activities such as land-use change, deforestation, biomass burning, and environmental pollution have accelerated the release of terrestrial carbon into the atmosphere, increasing the greenhouse effect. The study of soil organic carbon cycle was recognized in the last decades as a necessary step for controlling future increases in atmospheric CO2, as well as necessary to simultaneously ensure the sustainability agricultural activities. A better comprehension of the he dynamics of soil organic carbon (SOC) in different agricultural systems will allow an improvement of soil quality and soil organic carbon storage under different climate and soil conditions. However, despite of decade’s long research on this subject, there is still the need for a better appraisal of soil carbon dynamics in specific agricultural systems based on robust in field empirical studies. So, relevant contributions to a better understanding of the impact of land use on the global carbon cycle is of great importance.
The present research, framed in the context of a Ph.D. specialization on soil carbon in agricultural areas, is aimed to generate new information on the effect of different factors (climate, land use, management, altitude, and soil type) that influence the sequestration and accumulation of organic carbon along the profile in the soil in different agricultural and forest systems across contrasting edaphoclimatic conditions. This research includes not only new quantitative information on soil organic carbon, but also innovative studies on its distribution among different soil carbon compartments and on the use of near infrared spectroscopy (NIR) on soil organic carbon determination.
The first study (Chapter 2) is an analysis of the effect of different agricultural uses in a subtropical climate, in the area of the Carrizal River valley in the province of Manabí Ecuador, based on the analysis of 64 soil profiles. In each profile samples were taken in the soil profile horizons to obtain the concentration of organic carbon up to a maximum depth of 150 cm in different agricultural management (permanent, intensive rotation and abandoned crops), In this study twenty-one different agricultural uses were identified. As expected, the highest concentrations of soil organic carbon happened in the A horizon, which has an average thickness of 40 cm. A trend towards a higher carbon sequestration potential was observed in the grass, intercropping like cocoa with banana and corn area management with an average value of 1.7% C, much higher than the area under mechanized agriculture, which presented lower carbon concentration, with an average value of 0.26% C. Regarding the total soil organic carbon stock, the first horizon accumulated more carbon compared to the other (B and C) soil profiles, with an average value of 41.32±20.97 t C ha-1 and 15.06±15.61 t C ha-1, respectively.
The second study (Chapter 3) evaluated the effect of forest management in a temperate climate. For this study, soil samples were taken in a managed environment of forest species (Alnus incana, Fagus sylvatica, Picea abies and Mixed: stands containing beech} and spruce) in an elevation range from <900 m a.s.l. to >1100 m a.s.l. from the Babia Góra National Park in southern Poland. Sampling points were taken up to a maximum depth of 100 cm. The results in this study revealed that the SOC reserves in the mountain soils of the Babi Góra National Park are characterized by their great variability (from 50.10 t ha-1 to 905.20 t ha-1). In the conditions of this study, the type of soil is the dominant factor determining soil organic carbon stock, which coupled with topographic factors influence soil and vegetation conditions. This explains such diversity in the accumulation of soil organic carbon in different mountain soils in the areas. The largest carbon stock was recorded in histosols (>550 t C ha-1), which are located in the lower part of the national park.
The third block of the research focused on two field studies in one of the most important agroforestry systems across the Mediterranean, dehesa. The first study (Chapter 4) is located in a dehesa in Hinojosa del Duque in Córdoba, Spain: Dehesa is an agro-silvo-pastoral system which combines open land and low density trees (holm oaks). In this first study we investigated two adjacent dehesas on the same soil type but different characteristics. One was a pastureland with young holm oaks (planted in 1995 with a density of 70 trees ha-1 at 12 m x 12 m spacing. The area had been grazed by Merino sheep since 2000, at a grazing rate of 3 sheep per hectare. The second, adjacent area is a cultivated pasture with mature oaks with a minimum age of 90-100 years widely spaced (1.2 trees ha-1). Every three years, a mixture of peas and oats is grown for hay. Tillage is used for the preparation of this seeding except in the immediate vicinity (about 0.3-0.4 m) of the tree trunk. The first dehesa at higher tree density was part of this second dehesa, and so both had the same characteristics until year 1995. Both dehesas were sampled simultaneously in 2017. Sampling points were taken under and outside the canopy projection up to a maximum depth of 100 cm divided into 8 sections (0-2 cm, 2-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, 40-60 cm, 60-80 cm, and 80- 100 cm). The results showed that a change in dehesa type from an old low density dehesa combining pasture with seeding every 3 years to a one only pastured with increased tree growth (70 trees ha), showed no significant differences in carbon concentration after 22 years’ since implanting the more dense dehesa. A clear stratification of carbon was observed in the soil profile, particularly in the top 10 cm of the soil, as well as an effect of the adult tree which resulted in a higher concentration under the tree canopy in the middle soil depth section (20-40 cm) in the mature dehesa. Significant difference in carbon stock was only observed in the top 0-2 cm (5.86±0.56 t ha-1 vs 3.24±0.37 t ha-1, been higher in the newly planted dehesa. To our knowledge this is the first study evaluating in dehesa the distribution of soil organic carbon into this four (unprotected and physically, chemically and biochemically protected) fractions. Our results showed how most of the carbon in the two dehesas was stored in the unprotected fraction, been its relative contribution higher in the top 0-2 cm o the pastured dehesa and in the below canopy area of the mature trees in the cropped dehesa. This indicates that much of the fraction contained in these soils is particularly vulnerable to hypothetical changes to less sustainable managements.
The second study in dehesa (Chapter 5) was located in the municipality of Pozoblanco in the north of the province of Córdoba. In this area three areas of continuous extensive grazing for more than 50 years with cattle, sheep, and pigs were identified, and three areas with different intensity were studied. These areas were: I) Intensive grazing management. II) moderate grazing management and III) no grazing (area excluded for more than 20 years). Sampling points were taken at each of the three areas up to a maximum depth of 30 cm divided into 5 sections (0-2 cm, 2-5 cm, 5-10 cm, 10-20 cm, and 20-30 cm). Concentrations at different grazing intensities showed, as expected, higher carbon concentrations at the surface soil layer (0-2 cm) average of 1.59±0.44%, decreasing to 0.48±0.15% in the deeper section of the soil profile at 20-30 cm. Contradicting our initial hypothesis, no differences in soil organic carbon concentration were detected among the three areas with different grazing intensities, The total carbon stock was analyzed in the whole soil profile (0-30 cm), indicating non significant differences among the two grazed areas, average value of 27 t ha-1, or the area without grazing 26 t ha-1. As in the previous dehesa, the dominant fraction was the unprotected carbon. However, in this case the relative differences in the soil organic carbon concentration between the unprotected fraction and the physically and the chemically protected fractions was larger than in the first dehesa, particularly because the protected fractions tended to show a higher concentration than in the dehesa studied in Chapter 4.
Using the empirical results from the study of the second dehesa, we developed a spectral library and predictive equations of concentration of soil organic carbon using Vis-NIR (Chapter 6) from this dataset. The accuracy of the SOC predictive models was very good, with R2 higher than 0.95 and residual predictive deviation (RPD) higher than 4.54, respectively. Refinement of VIS-NIR techniques, such as the one discussed in Chapter 6, could increase our ability to provide more affordable and robust technologies to measure large numbers of samples with the required accuracy, although it is less clear how to address other important sources of variability, such as soil depth, soil type, bulk density, and rock content. To reduce this uncertainty will be of great relevance to continue performing detailed experiments to better quantify on the effect of land use and cropping systems on soil organic carbon content, such as those described in chapters 3, 5 and 5. To date, these experiments are irreplaceable to test specific hypothesis relevant at local level (like the time to increase soil organic carbon stock after planting at higher density, Chapter 4), but also to create a corpus of available data which could improve, or lead to new ones, conceptual or numerical simulation models that can systematize our understanding of the soil organic carbon cycle and eventually reduce the need for large-scale sampling to verify the evolution of soil organic carbon in agricultural systems.
... In fact, it has been largely demonstrated that drier and hotter climates favor SOC depletion in agricultural lands Francaviglia et al., 2019). Lugato et al. (2014b) estimated the content of SOC in European agricultural topsoils under different conditions through a modelling approach, which allowed for upscaling single spot measures of SOC content, taking into account also management practices and official statistics. According to their predictions, arable land was predicted to store 7.65 Gt of SOC (43% of total) in the first 30 cm of depth. ...
In the European Union, the setting of Operational Groups (OG) is supported by the European Innovation Partnership to tackle specific problems and favor innovation in agriculture. They constitute an important aspect of the current Common Agricultural Policy. Increasing or maintaining soil organic carbon (SOC) content under arable farming has been acknowledged as a primary target of European agriculture. SOC-preserving agriculture needs its techniques to be tailored to local conditions, namely, the combination of factors related to the environment (climate and soil characteristics), to the farming system (land use type, farm specialization, crop management), but also to the social and cultural context (market and availability of production means, subsidies, farmers’ education, propensity for innovation and change). In this paper we present inspirational ideas and show success examples of local adaptations strategies to increase or maintain SOC content in soils under arable farming in Europe. They include:
· Adoption of soil management strategies to improve SOC storage in irrigated systems.
· Precision farming and other high-tech solutions able to generate local diagnosis and adaptive strategies for increasing SOC and reducing greenhouse gasses emissions.
· Innovative strategies for extending soil cover periods and introducing cover crops in rotations in areas with limited water availability or prone to harsh weather conditions.
· Management of rainfed and low input crops to maintain and increase SOC in dry climates and erosive prone soils.
These case studies could facilitate the setting up of OGs and the application of innovative practices in different European countries.
... However, these results are not representative for Germany as a whole. Lugato et al. (2014) and Smith et al. (2005) estimated future changes in SOC stocks using the climate scenarios of the Intergovernmental Panel of Climate Change (IPCC) and the SOC models Roth-C (Coleman and Jenkinson 2005) and Century (Parton et al. 1994). They reported increasing SOC stocks for Europe for the end of the 21st century. ...
Aims
Increasing soil organic carbon (SOC) stocks is discussed as negative emission technology with the potential to remove relevant amounts of carbon from the atmosphere. At the same time, climate change-driven losses of SOC to the atmosphere might impede such goals.
Methods
In this study, we used an ensemble of different SOC models and climate projections to project SOC stocks in German croplands up to 2099 under different climate change scenarios. We then estimated the required increase in organic carbon (OC) input to preserve or increase SOC stocks.
Results
Projected SOC stocks of German croplands are estimated to decline under current OC input levels and management, both with and without climate change. Depending on the climate scenario, we estimated that the OC input to the soil in 2099 needs to be between 51% (+ 1.3 Mg ha − 1 ) and 93% (+ 2.3 Mg ha − 1 ) higher than today to preserve current SOC stock levels. A SOC stock increase of 34.4% (4‰ a − 1 ) would even require an OC input increase of between 221% (+ 5.5 Mg ha − 1 ) and 283% (+ 7.1 Mg ha − 1 ).
Conclusions
Our study highlights that under climate change increasing SOC stocks is considerable challenging since projected SOC losses have to be compensated first before SOC built up is possible. This would require unrealistically high OC input increases with drastic changes in agricultural management.
... The '4 per 1000' initiative proposes improving content OM by increasing C in soils by 0.4%, by implementing agricultural practices that will help achieve this increase. In this regard, knowledge of the existing C stock in soils is very relevant, and several studies are being carried out across the world using modelling techniques (Batjes, 2016;Aksoy et al., 2016;De Brogniez et al., 2015;Lugato et al., 2014). Integrating variables into these models that take into account the management system, such as CA for example, would provide more global data on the capacity of these practices for soil carbon capture in different agroecologies. ...
The contribution of the agricultural sector to climate change is gaining visibility, leading to increasing interest in learning how agriculture can mitigate greenhouse gas (GHG) emissions. Conventional agriculture based on soil tillage has driven numerous well-known environmental problems. It is a net GHG emitter and vulnerable to climate change. Conversely, Conservation Agriculture (CA) helps mitigate and adapt to climate change. CA reduces GHG concentration in the atmosphere in two ways. First, the changes introduced by CA increase the carbon in the soil, reducing its emissions. Second, the drastic reduction or avoidance of mechanical soil disturbance, along with no mechanical alteration of the soil, leads to reduction of the CO2 emissions due to energy saving and lower fuel consumption along with the reduction of the mineralization processes of organic matter. CA is a good strategy not only to mitigate climate change, but also to adapt agricultural ecosystems to its effects, by increasing crop resilience in the face of climatic variation. With CA systems, soil erosion is also reduced, and the quality and fertility of the soil is improved, allowing the crop to access more water in dry periods. CA can reverse agriculture’s field performance from that of a net GHG emitter to a GHG mitigator. It provides an alternative paradigm to the status quo of agriculture based on soil tillage, which is unacceptable from a climate point of view.
... Early attempts were the estimation of European SOC stocks based on pedotransfer functions, followed by the compilation of the LUCAS database with a representation of agricultural soils and the UN/ECE ICP Forests sites below 1000 m altitude (Jones et al., 2005;Tóth et al., 2013). The European efforts emphasize the assessment of SOC stocks in agricultural soils and their future development (Lugato et al., 2014;Yigini and Panagos, 2016). Forest soils have several peculiarities. ...
... Meena et al. (2018) suggested that restoration of degraded barren and cultivated land to grass and forest lands could increase soil C and N storage in Indian mid-Himalaya region. Indeed, land-use changes had critical effects on SOC and TN sequestrations, and understanding their impact process is essential for developing appropriate land planning strategies (Lugato et al., 2014). ...
In water-limited areas, revegetation of abandoned croplands may lead to extensive land-use changes and considerable variations on soil carbon (C) and nitrogen (N). However, the impact of land-use patterns (i.e., the spatial combinations of different land-use types) on soil C and N variations following revegetation remains unclear. In this study, we measured soil organic carbon (SOC), total carbon (TC), and total nitrogen (TN) stocks to a depth of 200 cm in grassland (GL), shrubland (SL), young forestland (YF), and mature forestland (MF) under four land-use patterns in a catchment located in the Chinese Loess Plateau. The highest SOC, TC and TN stocks occurred in MF and the lowest was found in GL. Compared to every single land-use type, soil C and N stocks significantly increased under different land-use patterns. The highest SOC stock (6.51 kg m⁻²) was found in the GL-YF-SL pattern, and the highest TC stock (47.25 kg m⁻²) and TN stock (0.70 kg m⁻²) were both observed in the MF-YF pattern. SOC stocks showed significantly positive correlations with TC and TN stocks under different land-use patterns (p < 0.05), except for the GL-MF. The soil C-N interactions were stronger in the MF-SL and GL-YF-SL patterns compared to the GL-MF and MF-SL. Redundancy analysis indicated that the SOC, TC, and TN variations were well explained by aboveground biomass and land-use patterns, with accumulated variance of 41.6% and 54.2% in Axis 1 and Axis 2, respectively. The differences of soil C and N accumulation among land-use patterns were mostly related to different vegetation coverage and the intensity of soil erosion. This study indicates that creating proper spatial distribution of land-use types on hillslopes could benefit soil C and N sequestrations and ecosystem restoration in semi-arid environments.
... Zissimos et al. (2019) estimated a total top-soil SOC stock of 27 Mt for the country (5500 km 2 ) of which 6 Mt was in forested areas (1180 km 2 ). The country-wide SOC estimates were similar to the mean SOC values from the modellingbased studies of Lugato et al. (2014) and Ballabio et al. (2014) for Cyprus, but lower than the average SOC (1.75%) from the 22 soil top 20-cm soil samples analyzed by the GEMAS project (Reimann et al., 2014). ...
Extensive areas of arable land have been abandoned in many countries around the world, especially in the Mediterranean region. The overall goal of this study is to assess the effects of agricultural land abandonment on soil organic carbon (SOC) concentrations and stocks in a Mediterranean mountain environment. The specific objectives are (i) to quantify differences in SOC concentrations in top 25-cm soil in productive agricultural areas, abandoned agricultural areas and state forests; (ii) to quantify SOC stocks in productive and abandoned terraced vineyards up to the bedrock or to a maximum depth of 80 cm and (iii) to analyze the effect of time of abandonment on the SOC stocks of the vineyards. Top soil SOC concentrations from 826 sampling points covering 2374 km² of mountainous areas (Troodos Mountains, Cyprus) with a variety of land covers were used. SOC stocks were determined from soil samples, which were collected up to the bedrock, where possible, from 24 productive and abandoned terraced vineyards (paired-sites). The Loss-on-Ignition method and an elemental carbon analyzer were used for SOC concentrations. Coarse fragment corrections were made for SOC stock calculations. Time of abandonment was estimated with aerial photos taken in 1963 and 1993. The average SOC concentration in the top soil (0–25 cm) ranged between 1.7% in state forests to 1.0% in productive agricultural land, while the mean value of abandoned fields was 1.3%. Regarding SOC in the top soil (0–10-cm) of paired vineyards, concentrations were higher in abandoned (1.4% SOC) than in productive sites (0.9% SOC), with a statistical significance level <0.05. Paired t-tests showed that SOC was lower in productive sites (0.9% SOC) compared to abandoned sites, with SOC (%) and statistical significance increasing with time of abandonment: 1.2% SOC in sites abandoned after 1993 (p-value 0.18) and 1.6% SOC in sites abandoned before 1963 (p-value 0.05). However, mean SOC stocks, with coarse fragment correction, were slightly higher for the productive sites (22 Mg ha⁻¹) than for the abandoned sites (21 Mg ha⁻¹) and showed no trend with the time of abandonment (p-value: 0.85). The coarse fragment corrections resulted in 17 to 78% reduction in SOC stocks. Our results showed the importance of deep soil sampling (>30 cm) and coarse fragment corrections for quantifying SOC stock. Despite higher SOC concentrations for abandoned sites, SOC stock calculations resulted in similar mean SOC stock values for productive and abandoned terraced vineyards, indicating the importance of erosional and depositional processes in such landscapes.
... Based on a research study of organic carbon stocks in agricultural land of Europe conducted using a CENTURY model (Lugato et al., 2014), a value of 17.63 Gt for a 0-30 cm layer was obtained. The model included the EU and non-EU countries (Serbia, Bosnia and Herzegovina, Croatia, Albania, Macedonia, and Norway). ...
Correlation between soil organic carbon (SOC) and land use and soil type were
investigated in the soils of the Republic of Serbia. The database included a
total of 1,140 soil profiles. To establish the correlation between organic
carbon content and soil type, a soil map of Serbia was adapted to the WRB
classification and divided into 15,437 polygons (map units). The SOC stock
values were calculated for each reference soil group based on mean values of
SOC at 0-30 and 0-100 cm and their areas. The largest SOC stocks for the
soil layers 0-30 cm were found in Cambisol 194.76 x 1012 g and Leptosol
186.43 x 1012 g and for the soil layers 0-100 cm in Cambisol 274.87 x 1012 g
and Chernozem 230.43 x 1012 g. Using the Corine Land Cover (CLC) database,
the major categories of land use were defined. Based on the obtained mean
values of organic carbon content for the soil layers 0-30 and 0-100 cm and
the areas indicated by Corine Land Cover categories of land use, the organic
carbon stocks in agricultural soil, forest soil, semi-natural areas, and
artificial areas were calculated. The correlation of organic carbon stocks
and the different land use categories, soil reference group, and soil depth
was studied for reference groups that occupy the major part of central
Serbia, such as Cambisol (taking up 37.76% of the territory) and Leptosol
(22.22% of the territory), and have a sufficient number of sites that were
required for this type of analysis.
... Approaches to capture SOC dynamics that do more justice to the underlying physical, chemical and biological processes make use of semi-mechanistic models, such as RothC and CENTURY (e.g., Abramoff et al., 2018;Gottschalk et al., 2012;Karunaratne, Bishop, Lessels, Baldock, & Odeh, 2015;Lugato, Panagos, Bampa, Jones, & Montanarella, 2014;Smith et al., 2005;Woolf & Lehmann, 2019). Alternatively, Earth System Models have also been used (e.g., Todd-Brown et al., 2014). ...
Spatially resolved estimates of change in soil organic carbon (SOC) stocks are necessary for supporting national and international policies aimed at achieving land degradation neutrality and climate change mitigation. In this work we report on the development, implementation and application of a data‐driven, statistical method for mapping SOC stocks in space and time, using Argentina as a pilot. We used Quantile Regression Forest machine‐learning to predict annual SOC stock at 0–30 cm depth at 250 m resolution for Argentina between 1982 and 2017. The model was calibrated using over 5,000 SOC stock values from the 36‐year time period and 35 environmental covariates. We pre‐processed NDVI dynamic covariates using a temporal low‐pass filter to allow the SOC stock for a given year to depend on the NDVI of the current as well as preceding years. Predictions had modest temporal variation with an average decrease for the entire country from 2.55 kg C m−2 to 2.48 kg C m−2 over the 36‐year period (equivalent to a decline of 211 Gg C, 3.0% of the total 0–30 cm SOC stock in Argentina). The Pampa region had a larger estimated SOC stock decrease from 4.62 kg C m−2 to 4.34 kg C m−2 (5.9%) during the same period. For the 2001–2015 period, predicted temporal variation was 7‐fold larger than that obtained using the Tier 1 approach of the IPCC and UNCCD. Prediction uncertainties turned out to be substantial, mainly due to the limited number and poor spatial and temporal distribution of the calibration data, and the limited explanatory power of the covariates. Cross‐validation confirmed that SOC stock prediction accuracy was limited, with a Mean Error of 0.03 kg C m−2 and a Root Mean Squared Error of 2.04 kg C m−2. In spite of the large uncertainties, this work showed that machine learning methods can be used for space–time SOC mapping and may yield valuable information to land managers and policy makers, provided that SOC observation density in space and time is sufficiently large. This article is protected by copyright. All rights reserved.
... The combination of simulation models and locally measured data is very critical in providing important information on SOC dynamics attributable to the complex nature of the soil-plant-atmosphere system (Francaviglia et al., 2012) which is invariably lacking on the African continent. For climate change policymakers and farmers, such information forms the bedrock of their decision in the identification and adoption of the most effective soil carbon sequestration management practices (Lozano-García et al., 2017;Lugato et al., 2014). The use of simulation models in conjunction with locally measured data to investigate soil carbon dynamics is very helpful because of the complexity of the soil -plant-atmosphere system. ...
Land use land cover change (LULCC) is a global environmental trend that plays a key role in worldwide environmental change and sustainable development. Substantial disturbance resulting from natural and anthropogenic activities has been witnessed in sub-Sahara Africa (SSA) over the last four decades, which is mostly due to the increasing population being experienced in Africa. One-third of emitted greenhouse gases (GHG) are attributable to LULCC and agricultural activities most especially deforestation. Soil carbon sequestration has been considered as a possible strategy to counterbalance carbon dioxide (CO2) emissions and mitigate global climate change, driven by rising concentrations of GHG in the atmosphere and global increase in temperature. The role of tropical Africa's forests in mitigating climate change has been widely acknowledged under the global treaties' Reducing Emissions from Deforestation and Degradation (REDD) initiatives. More than two-thirds of the SSA population rely on forests and woodlands for their livelihoods. Despite the importance of forests, Sub-Saharan Africa, and even the entire African continent, is experiencing an acceleration in deforestation, leading to diminished ecosystem resilience. Subsistence and commercial agriculture accounted for 10% of total forest land loss in Africa (approximately 75 million ha) between 1990 and 2010. As a result, agricultural expansion alone accounts for 70–80% of Africa's total forest loss. The challenges of implementing a policy to reduce emissions from deforestation and forest degradation, and foster conservation, sustainable management of forests, and enhancement of forest carbon stocks (REDD +) in the SSA includes interactions between a number of anthropogenic-induced factors and challenges. These factors, which are of various types (economic, institutional, etc.), cause loss of forest and forest degradation; and the challenges arising from finance, institutional and technical expertise hinder the appropriate design and implementation of national forest monitoring schemes. These challenges must be adequately addressed in order to accurately quantify the carbon budgets and implement an appropriate forest and carbon monitoring system for REDD + in SSA. Therefore, in meeting the REDD + initiatives in SSA, integrated land use management approach that enhances soil carbon sequestration potential should be given considerable systematic and scientific attention. In addition, political, socioeconomic and institutional factors that hinder sustainable forest management and land use system management must be addressed collectively.
... EPIC-IIASA Cropland: static 1 × 1 km cropland mask from CORINE-PELCOM. Initial SOC stock from the map of organic carbon content in the topsoil (Lugato et al., 2014). Static crop management and input intensity by NUTS2 calibrated for 1995-2010 (Balkovič et al., 2013). ...
p>Reliable quantification of the sources and sinks of atmospheric carbon dioxide (CO2), including that of their trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Kyoto Protocol and the Paris Agreement. This study provides a consolidated synthesis of estimates for all anthropogenic and natural sources and sinks of CO2 for the European Union and UK (EU27 + UK), derived from a combination of state-of-the-art bottom-up (BU) and top-down (TD) data sources and models. Given the wide scope of the work and the variety of datasets involved, this study focuses on identifying essential questions which need to be answered to properly understand the differences between various datasets, in particular with regards to the less-well-characterized fluxes from managed ecosystems. The work integrates recent emission inventory data, process-based ecosystem model results, data-driven sector model results and inverse modeling estimates over the period 1990-2018. BU and TD products are compared with European national greenhouse gas inventories (NGHGIs) reported under the UNFCCC in 2019, aiming to assess and understand the differences between approaches. For the uncertainties in NGHGIs, we used the standard deviation obtained by varying parameters of inventory calculations, reported by the member states following the IPCC Guidelines. Variation in estimates produced with other methods, like atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), arises from diverse sources including within-model uncertainty related to parameterization as well as structural differences between models. In comparing NGHGIs with other approaches, a key source of uncertainty is that related to different system boundaries and emission categories (CO2 fossil) and the use of different land use definitions for reporting emissions from land use, land use change and forestry (LULUCF) activities (CO2 land). At the EU27 + UK level, the NGHGI (2019) fossil CO2 emissions (including cement production) account for 2624 Tg CO2 in 2014 while all the other seven bottom-up sources are consistent with the NGHGIs and report a mean of 2588 (± 463 Tg CO2). The inversion reports 2700 Tg CO2 (± 480 Tg CO2), which is well in line with the national inventories. Over 2011-2015, the CO2 land sources and sinks from NGHGI estimates report-90 Tg C yr-1 ± 30 Tg C yr-1 while all other BU approaches report a mean sink of-98 Tg C yr-1 (± 362 Tg of C from dynamic global vegetation models only). For the TD model ensemble results, we observe a much larger spread for regional inversions (i.e., mean of 253 Tg C yr-1 ± 400 Tg C yr-1). This concludes that (a) current independent approaches are consistent with NGHGIs and (b) their uncertainty is too large to allow a verification because of model differences and probably also because of the definition of "CO2 flux"obtained from different approaches. The referenced datasets related to figures are visualized.</p
... Few countries have such monitoring schemes. The European Union (EU) started around 10 years ago with a Pan-European monitoring network to improve sustainable farming solutions and monitor soil pollution [16,17]. ...
Background: Legacy data are unique occasions for estimating soil organic carbon (SOC) concentration changes and spatial variability, but their use showed limitations due to the sampling schemes adopted and improvements may be needed in the analysis methodologies. When SOC changes is estimated with legacy data, the use of soil samples collected in different plots (i.e., non-aligned data) may lead to biased results. In the present work, N = 302 georeferenced soil samples were selected from a regional (Sicily, south of Italy) soil database. An operational sampling approach was developed to spot SOC concentration changes from 1994 to 2017 in the same plots at the 0–30 cm soil depth and tested.
Results: The measurements were conducted after computing the minimum number of samples needed to have a reliable estimate of SOC variation after 23 years. By applying an effect size based methodology, 30 out of 302 sites were resampled in 2017 to achieve a power of 80%, and an = 0.05.
A Wilcoxon test applied to the variation of SOC from 1994 to 2017 suggested that there was not a statistical difference in SOC concentration after 23 years (Z = − 0.556; 2-tailed asymptotic significance = 0.578). In particular, only 40% of resampled sites showed a higher SOC concentration than in 2017.
Conclusions: This finding contrasts with a previous SOC concentration increase that was found in 2008 (75.8% increase when estimated as differences of 2 models built with non-aligned data), when compared to 1994 observed data (Z = − 9.119; 2-tailed asymptotic significance < 0.001). This suggests that the use of legacy data to estimate SOC concentration dynamics requires soil resampling in the same locations to overcome the stochastic model errors. Further experiment is needed to identify the percentage of the sites to resample in order to align two legacy datasets in the same area.
... The field with high SOC content in zone A was converted from cropland to grassland in 2017, while the neighboring field remained under cropland. This in agreement with Lugato et al. (2013) who used the CENTURY model to simulate the carbon sequestration potential of different management practices on 12%-28% of European arable land, and the results showed that the change in land use from arable to grassland had the highest carbon sequestration potential with respect to all the others simulated practices. Poeplau & Don (2013) also stated that conversion from cropland to grassland resulted in an average SOC accumulation of 17 ± 5 Mg ha − 1 SOC in the topsoil (0-30 cm). ...
Accurate soil organic carbon content estimation is critical as a proxy for carbon sequestration, and as one of the indicators for soil health. Here, we collected 497 soil samples during 2015 and 2019, as well as five environmental covariates (organic carbon (OC) input from the crops, normalized difference vegetation index (NDVI), elevation, clay content and precipitation) at a resolution of 30 m. We then aggregated these to represent agricultural fields and compiled a soil organic carbon (SOC) content map for the agricultural soils of Wallonia using Gradient Boosting Machine. We calculated OC input from both main crops and cover crops for each individual field. As the cover crops do not occur in the agricultural census, we identified cover crops based on long time-series of NDVI values obtained from the Google Earth Engine platform. The quality of the SOC predictions was assessed by validation data and we obtained an R² of 0.77. The Empirical Mode Decomposition indicated that OC input and NDVI were the dominant factors at field scale, whereas the remaining covariates determined the distribution of SOC at the scale of the entire Walloon region. The SOC map showed an overall northwest to southeast trend i.e. an increase in SOC contents up to the Ourthe river followed by a decrease further to the South. The map shows both regional trends in SOC and effects of differences in land use and/or management (including crop rotation and frequency of cover crops) between individual fields. The field-scale map can be used as a benchmark and reference to farmers and agencies in maintaining SOC contents at an appropriate level and optimizing decisions for sustainable land use.
... Our ensemble estimate for topsoil SOC (0-30 cm) contents across EU-27 in 1999 (i.e. after spin-up and before alteration of residue management) is with on average 51 t C ha −1 approx. 30-35% lower than earlier modelling based estimates by Lugato et al. (2014b) and Smith et al. (2005) (82-87 t C ha −1 ). However, it agrees well with a current detailed field survey for Germany, which estimated that topsoil carbon stocks of croplands are about 58 t C ha −1 (Riggers et al., 2021) compared to SOC mean of 53 t C ha −1 for Germany in 1999 in our study (data not shown). ...
Application of crop residues to agricultural fields is a significant source of the greenhouse gas nitrous oxide (N2O) and an essential factor affecting the soil organic carbon (SOC) balance. Here we present a biogeochemical modelling study assessing the impact of crop residue management on soil C stocks and N2O fluxes for EU-27 using available information on soils, management and climate and by testing various scenarios of residue management. Three biogeochemical models, i.e. CERES-EGC, LandscapeDNDC and LandscapeDNDC-MeTrx, were used in an ensemble approach on a grid of 0.25° × 0.25° spatial resolution for calculating EU-27 wide inventories of changes in SOC stocks and N2O emissions due to residue management for the years 2000–2100 using different climate change projections (RCP4.5 and RCP8.5). Our results show, that climate change poses a threat to cropping systems in Europe, resulting in potential yield declines, increased N2O emissions and loss of SOC. This highlights the need for adapting crop management to mitigate climate change impacts, e.g. by improved residue management. For a scenario with 100% residues retention and reduced tillage we calculated that in average SOC stocks may increase over 50–100 years by 19–23% under RCP8.5 and RCP4.5. However, complete retention of crop residues also resulted in an increase of soil N2O emissions by 17–30%, so that climate benefits due to increases in SOC stocks were eventually compensated by increased N2O emissions. The long-term EFN2O for residue N incorporation was 1.18% and, thus slightly higher as the 1% value used by IPCC. We conclude that residue management can be an important strategy for mitigating climate change impacts on SOC stocks, though it requires as well improvements in N management for N2O mitigation.
... Despite having detailed national SOC data sets in several EU-28 states, a consistent estimation of SOC stocks at the EU scale remains problematic. To create a new baseline of SOC in EU agricultural soils and to provide a powerful, dynamic tool to orient future European policies for carbon sequestration, a Pan-European model application was established [21], using the SOC model CENTURY [22]. SOC stocks were calculated for 164,000 combinations of soil-climate-land-use combinations, including the main arable crops, orchards and pastures. ...
Globally, agricultural soils are being evaluated for their role in climate change regulation as a potential sink for atmospheric carbon dioxide (CO2) through sequestration of organic carbon as soil organic matter. Scientists and policy analysts increasingly seek to develop programs and policies which recognize the importance of mitigation of climate change and insurance of ecological sustainability when managing agricultural soils. In response, many countries are exploring options to develop local land-use carbon inventories to better understand the flow of carbon in agriculture to estimate its contribution to greenhouse gas (GHG) reporting. For instance, the Canadian province of Ontario does not currently have its own GHG inventory and relies on the Canada’s National Inventory Report (NIR). To address this, the province explored options to develop its own land-use carbon inventory to better understand the carbon resource in agricultural soils. As part of this undertaking, a gap analysis was conducted to identify the critical information gaps and limitations in estimating soil organic carbon (SOC) monitoring to develop a land-use carbon inventory (LUCI) for the cropland sector in Ontario. We conducted a review of analytical and modeling methods used to quantify GHG emissions and reporting for the cropland sectors in Canada, and compared them with the methods used in seven other countries (i.e., France, United Kingdom; Germany; United States of America, Australia, New Zealand, and Japan). From this comparison, four target areas of research were identified to consider in the development of a cropland sector LUCI in Ontario. First, there needs to be a refinement of the modelling approach used for SOC accounting. The Century model, which is used for Ontario’s cropland sector, can benefit from updates to the crop growth model and from the inclusion of manure management and other amendments. Secondly, a raster-based spatially explicit modelling approach is recommended as an alternative to using polygon-based inputs for soil data and census information for land management. This approach can leverage readily available Earth Observation (EO) data (e.g., remote sensing maps, digital soil maps). Thirdly, the contributions from soil erosion need to be included in inventory estimates of SOC emissions and removals from cropland. Fourth, establishment of an extensive network of long-term experimental sites to calibrate and validate the SOC models (i.e., CENTURY) is required. This can be done by putting in place a ground-truth program, through farmer-led research initiatives and collaboration, to deal with uncertainties due to spatial variability and regional climates. This approach would provide opportunities for farmers to collaborate on data collection by keeping detailed records of their cropping and soil management practices, and crop yields.
... Despite having detailed national SOC data sets in several EU-28 states, a consistent estimation of SOC stocks at the EU scale remains problematic. To create a new baseline of SOC in EU agricultural soils and to provide a powerful, dynamic tool to orient future European policies for carbon sequestration, a Pan-European model application was established [21], using the SOC model CENTURY [22]. SOC stocks were calculated for 164,000 combinations of soil-climate-land-use combinations, including the main arable crops, orchards and pastures. ...
... Map of predicted soil organic carbon stock in agricultural soils of Italy. Data was obtained using the agro-ecosystem model CENTURY and validated with the LUCAS 2009 soil samples and the EIONET-SOIL inventory(Lugato et al., 2014). ...
Biogas production and use can represent a win-win strategy providing multiple opportunities to mitigate the emission of greenhouse gases responsible for climate change, while offering a range of important social, environmental and economic benefits. Nevertheless, as for other bioenergy pathways, biogas sustainability needs to be carefully assessed and continuously monitored in light of the specific geographic and temporal context in which it performs. This paper aims to provide a comprehensive review on the sustainability assessment of domestic production and use of biogas in Italy, with a focus on the environmental dimension of the sustainability. Furthermore, it elaborates on the results of the review to perform an ex-novo sustainability assessment of biogas pathway at national level, through the methodology developed by the Global Bioenergy Partnership. The biogas value chain in Italy can play a positive role to foster the transition towards an ecological and circular economy. This paper highlights both weaknesses and strengths of the biogas value chain in Italy and points out existing differences, in relation to the sustainability of the value chain, between various geographical areas of the country. The outcomes of this study could inform, both at national and international scale, the drawing of tailor-made policies and measures to reduce biogas-related potential risks of environmental impacts, as well as to support the replication and scaling up of successful management practices. Furthermore, they could serve as a baseline for the future monitoring of the sector. Ultimately, the paper reports the key difficulties encountered in the implementation of the GBEP methodology and the solutions adopted to overcome them.
... Bulk density values of LUCAS sites were estimated with a pedotransfer function previously recommended for European agricultural soils by Hollis et al. (2012). The bulk density values obtained were used to convert SOC contents to stocks (Lugato et al., 2014): ...
Treatment effects are traditionally quantified in controlled experiments. However, experimental control is often achieved at the expense of representativeness. Here, we present a data-driven reciprocal modelling framework to quantify the individual effects of environmental treatments under field conditions. The framework requires a representative survey dataset describing the treatment (A or B), its responding target variable, and other environmental properties that cause variability of the target within the region or population studied. A machine learning model is trained to predict the target only based on observations in group A. This model is then applied to group B, with predictions restricted to the model’s space of applicability. The resulting residuals represent case-specific effect size estimates and thus provide a quantification of treatment effects. This paper illustrates the new concept of such data-driven reciprocal modelling to estimate spatially explicit effects of land-use change on organic carbon stocks in European agricultural soils. For many environmental treatments, the proposed concept can provide accurate effect size estimates that are more representative than could feasibly ever be achieved with controlled experiments.
... SOM stock in our research is similar to the typical stock of organic matter in the northern agricultural soils of Norway, Sweden and Finland. In these countries, the SOM stock in the northernmost agricultural soils is estimated at 70 to 200 t×ha (mean values for topsoil horizon 0-30 cm)(Lugato et al. 2014, Rusco et al. 2001. For soils in northern Canada, the SOM stock is 118 t×ha in the northern Arctic and 240 t×ha in the southern Arctic in the 0-50 cm horizon(Hossain et al. 2007). ...
Recently, questions about the return of the concept of Arctic agriculture in order to promote sustainable development of the northern regions and ensure food security have been raised more often. The re-involvement of previously-used and abandoned soils into agricultural usage can provide an essential contribution for the development of the Arctic regions. We conducted a comprehensive research of soils with different levels of abandonment in the central part of the Yamal Region (Russia) and compared their morphological features, chemical and physical properties, fertile qualities and the level of contamination with heavy and trace metals to background soils of the region. It has been noted that there are no evident features of cryoturbation processes in the profiles of abandoned agricultucal soils and regular changes in the redox regime, as a consequence of the presence of reductimorphic spots in the soil profiles, have been recorded. Soil organic matter (SOM) stock in the topsoil of abandoned soils is estimated as medium and has a similar level to the stocks of total organic matter in the agricultural soils of the Arctic circumpolar region (Norway, Sweden, and Finland). Statistically significant differences in the content of nutrients between abandoned and background soils were recorded which indicates stability of the soil nutritional state during different abandoned states. Particularly notable are the differences between the content of available forms of phosphorus. The results of the study revealed significant differences between soils of various periods of abandonment and the background soils of the Yamal Region. Abandoned soils can be used for ground and greenhouse agriculture, these soils having a high level of fertility and are not limited for use in agriculture by the level of contamination with heavy and trace metals. According to the character of trace metal contamination, abandoned and background soils are evaluated as uncontaminated on the base of Zc and Igeo indices values. Reuse of the previously abandoned soils can undoubtedly become the basis for increasing agricultural production and ensuring food security in the Yamal Region.
... As examples of soil degradation in the EU, we estimated that 13% of soils suffer from high erosion with on-site costs of 1.25 billion Euro due to yearly losses in agricultural productivity . Every year, mineral soils lose 7.4 million tonnes of carbon due to nonsustainable management (Lugato et al., 2014). According to the Court of Auditors report (ECA, 2018), 25% of land in Southern and Eastern Europe is at high risk of desertification. ...
Soils provide crucial ecosystem services such as the provision of food, carbon sequestration and water purification. Soil is the largest terrestrial pool of carbon, hosts more than 25% of all biodiversity and provides 95–99% of food to 8 billion people. The European Union (EU) puts the concept of healthy soils at the core of the European Green Deal to achieve climate neutrality, zero pollution, sustainable food provision and a resilient environment.
Given the European Union's objective to become the first climate neutral continent by 2050, the European Commission adopted a series of communications for a greener Europe. In 2020, an ambitious package of measures were presented within the Biodiversity 2030, Farm to Fork and Chemicals Strategies, as well as the Circular Economy Action Plan and the European Climate Law, which included actions to protect soils (Montanarella and Panagos, 2021). In 2021, these were followed by the Fit for 55 package, the Zero Pollution Action Plan and the EU Soil Strategy for 2030.
... It is, therefore, crucial to assess the balance of these contrasting processes considering the risk that climate change will be accelerated through SOC being released into the atmosphere as carbon dioxide (i.e., positive carbon cycle-climate feedback; see e.g., Bradford et al., 2016). Recently, the SOC cycle response and feedback to climate change have been studied using ecosystem modeling (Lugato et al., 2014;Riggers et al., 2021), field-and mesocosm-based warming experiments (Melillo et al., 2017;Poeplau et al., 2017), and global databases of soil-to-atmosphere respiration (Bond-Lamberty et al., 2018). ...
One fourth of the global soil organic carbon (SOC) is stored in boreal region, where climate change is predicted to be faster than the global average. Planetary warming is accelerated if climate change promotes SOC release into the atmosphere as carbon dioxide. However, the soil carbon‐climate feedbacks have been poorly confirmed by SOC measurements despite of their importance on global climate. In this study we used data collected as part of the Finnish arable soil monitoring program to study the influence of climate change, management practices and historical land use on changes in SOC content using a Bayesian approach. Topsoil samples (n=385) collected nationwide in 2009 and 2018 showed that SOC content has decreased at the rate of 0.35% yr‐1 on average. Based on Bayesian modelling of our data we can say with a certainty of 79‐91% that increase in summertime (May‐Sep) temperature has resulted in SOC loss while increased precipitation has resulted in SOC loss with a certainty of 90‐97%. The exact percentages depend on the climate dataset used. Historical land use was found to influence the SOC content for decades after conversion to cropland. Former organic soils with high SOC‐to‐fine‐fraction ratio were prone to high SOC loss. In fields with long cultivation history (>100 years), however, the SOC‐to‐fine‐fraction ratio had stabilized to approximately 0.03‐0.04 and the changes in SOC content leveled off. Our results showed that, although arable SOC sequestration can be promoted by diversifying crop rotations and by cultivating perennial grasses, it is unlikely that improved management practices are sufficient to counterbalance the climate change induced SOC losses in boreal conditions. This underlines the importance of reduction of greenhouse gas emissions to avoid the acceleration of planetary warming.
... These differences may be due to the carbon contribution from the decomposition of vegetation associated with current land use [57,64,65]. In the study area, the vegetation grown in the abandoned soils is currently forest vegetation. ...
The low profitability of agricultural products in a globalized market context is causing the abandonment of less profitable agroforestry systems in Spain. This fact is implicated in a change in land use, increasing the forest area, which could alter the carbon stock in the soil. Thus, the objective of this study was to determine if the abandonment of rural areas and the change in land use has an impact on the soil organic carbon stock in agroforestry systems in southwestern Spain. Through historical aerial photographs and current satellite images, sites were identified where samples of abandoned agricultural soils in the 1950s were collected. They were compared with soil samples from adjacent locations whose agricultural activities continue to this day. After more than 60 years, the abandonment of agricultural activity is associated with a 54% increase in C concentration and 34.8% in soil organic carbon in the upper 30 cm of soil profiles. Therefore, the abandonment of agricultural land has influenced the carbon stock of this territory, becoming a carbon sink.
... High plant species diversity provides a range of habitats for both breeding and migratory birds (Báldi et al., 2013). European grasslands are also estimated to store 5.5 Gt of carbon in the top 30 cm of soils (Lugato et al., 2013), which provides an important pedologic carbon store, particularly coastal grasslands (McLeod et al., 2011), and can exceed that of tropical rainforests (Pendleton et al., 2012). ...
Agriculture has been identified as one of the main drivers of environmental degradation in the European Union (EU). It can have negative impacts on air, water, soil and biodiversity. The condition of agroecosystems is affected by soil degradation, especially by soil erosion, which reduces agroecosystems’ capacity to provide essential ecosystem services. Therefore, it is necessary to explore synergies and trade-offs between pressures,
ecosystem condition and services to create relevant information for policy and decision-makers to implement sustainable response actions.
As part of the EU environmental policy, the Mapping and Assessment of Ecosystems and their Services (MAES) Working Group developed appropriate concepts to assess and link ecosystem condition and services. This study aims to test the indicators proposed by MAES to assess ecosystem condition and link it with the ecosystem services provision. For this, we applied a suggested operational framework developed in the context of the
Biodiversity Strategies 2020 and 2030 for the integrated assessment of agroecosystems and regulating ecosystem service control of erosion rates supply at European scale. We quantified and mapped indicators for ecosystem condition, environmental and anthropogenic pressures and soil erosion control. We explored the relationships
between the respective indicators and the capacity of agroecosystems to control soil erosion across the different Environmental Zones (EZ).
Our results indicate that, in general, European agroecosystems have a high capacity to control soil erosion with some variations within the EZ. Supply capacity is positively, negatively and not correlated with the various pressure and condition indicators. Management and climate indicators play a significant role in the assessment of
this service. These results highlight that conservational management practices are fundamental to reduce soil loss and improve agroecosystem condition. However, the design and implementation of such management practices must consider regional and local landscape characteristics, agricultural practices and the needs and opportunities
of stakeholders.
In response to climate change, prolonged droughts in semiarid regions have increased; consequently, reservoir sediments have been more frequently exposed to the atmosphere. Because of the large proportion of drawdown areas, reservoir sediments are used for agricultural activity. Agricultural intensification creates new biochemically active spots that may enhance the fluxes of carbon dioxide (CO2) and methane (CH4) after reservoir refilling. Here, we experimentally evaluated the influence of rewetting on CO2 and CH4 fluxes from the drawdown area of a Brazilian semiarid reservoir with and without agricultural activity. The observed CO2 and CH4 emissions were two and three times higher, respectively, in the sediment with agricultural activity. Higher values of organic carbon, organic matter, and nutrients in the crop-related sediment were the best predictors for the highest CO2 and CH4 emission rates. It is essential to better understand regional scenarios, such as emissions from semiarid regions, to refine the role of human-made reservoirs in the global C balance. Agricultural practices are becoming increasingly common because of extended droughts that keep reservoir sediment exposed to the atmosphere for longer periods. The response of sediments to crops suggests that land-use changes can promote positive and powerful climate feedback.
Reliable quantification of the sources and sinks of atmospheric carbon dioxide (CO2), including that of their trends and uncertainties, is essential to monitoring the progress in mitigating anthropogenic emissions under the Kyoto Protocol and the Paris Agreement. This study provides a consolidated synthesis of estimates for all anthropogenic and natural sources and sinks of CO2 for the European Union and UK (EU27 + UK), derived from a combination of state-45 of-the-art bottom-up (BU) and top-down (TD) data sources and models. Given the wide scope of the work and the variety of datasets involved, this study focuses on identifying essential questions which need to be answered to properly understand the differences between various datasets, in particular with regards to the less-well characterized https://doi.org/10.5194/essd-2020-376 Open Access Earth System Science Data Discussions Preprint. Discussion started: 18 December 2020 c Author(s) 2020. CC BY 4.0 License. 2 fluxes from managed ecosystems. The work integrates recent emission inventory data, process-based ecosystem model results, data-driven sector model results, and inverse modelling estimates, over the period 1990-2018. BU and 50 TD products are compared with European national GHG inventories (NGHGI) reported under the UNFCCC in 2019, aiming to assess and understand the differences between approaches. For the uncertainties in NGHGI, we used the standard deviation obtained by varying parameters of inventory calculations, reported by the Member States following the IPCC guidelines. Variation in estimates produced with other methods, like atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), arise from diverse sources including within-model uncertainty related 55 to parameterization as well as structural differences between models. In comparing NGHGI with other approaches, a key source of uncertainty is that related to different system boundaries and emission categories (CO2 fossil) and the use of different land use definitions for reporting emissions from Land Use, Land Use Change and Forestry (LULUCF) activities (CO2 land). At the EU27+UK level, the NGHGI (2019) fossil CO2 emissions (including cement production) account for 2624 Tg CO2 in 2014 while all the other seven bottom-up sources are consistent with the NGHGI and 60 report a mean of 2588 (± 463 Tg CO2). The inversion reports 2700 Tg CO2 (± 480 Tg CO2), well in line with the national inventories. Over 2011-2015, the CO2 land sources/sinks from NGHGI estimates report-90 Tg C yr-1 ± 30 Tg C while all other BU approaches report a mean sink of-98 Tg yr-1 (± 362 Tg C from DGVMs only). For the TD model ensemble results, we observe a much larger spread for regional inversions (i.e., mean of 253 Tg C yr-1 ± 400 Tg C yr-1). This concludes that a) current independent approaches are consistent with NGHGI b) their uncertainty is 65 too large to allow a "verification" because of model differences and probably also because of the definition of "CO2 flux" obtained from different approaches. The referenced datasets related to figures are visualized at https://doi.org/10.5281/zenodo.4288883 (Petrescu et al., 2020).
The EU LULUCF Regulation considers, for the first time, a separate target for the land use, land use change and forestry (LULUCF) sector. The sector is also supposed to contribute to the legally bind-ing target of net zero greenhouse gas (GHG) emissions by 2050 proposed by the European Climate Law. Hence, the importance of the LULUCF sector emissions have increased. This requires a critical review of completeness, accuracy and consistency of LULUCF reporting and accounting. But the rules for reporting and accounting as laid out in the EU LULUCF Regulation also need to better reflect this importance by setting incentives for land management improvement.
This briefing highlights challenges in GHG reporting and accounting for cropland, harvested wood products, forest management change and organic soils, e.g. related to uncertainty, lack of data and high level of aggregation, assesses the implications of these challenges on environmental integrity and incentives for improving land management.
Inaccurate accounts of cropland emissions and removals lead to hidden emissions but also hidden mitigation potentials which has implications for incentivising changes in management. Countries are more likely to increase their ambition level in LULUCF if there is a closer connection between con-crete management practices, co-benefits of other policy targets (e.g. area of organic farming, hec-tares of restored ecosystems) and GHG inventories. Climate protection on cropland can only be effective with much higher granularity of reporting than currently applied by EU Member States (MS).
Also, the rather coarse representation of harvested wood products (HWP) in most GHG accounts of EU countries might lower incentives for mitigation measures involving HWP overall. An accurate initialisation of HWP pools is crucial but also a challenge for MS facing lack of data. There can also be inconsistencies in MS’s HWP accounts because of discrepancies between harvest statistics and national forest inventories. However, as HWP is part of the reference level (FRL) that combines HWP and forest pools, the implications of inconsistencies are probably limited.
Whether impacts of changes in forest management on forest carbon stocks are accurately ac-counted for, depends also on the stratification of forests in GHG inventories and FRL. If forest strat-ification for reporting is too coarse, management changes might not be visible in the GHG accounts. The risk of undetected emissions and removals in forest inventories appear to be limited for reporting of forest biomass. For other forest carbon pools, the risk depends on the effect that management changes have on them. This depends again on the type of change and can result in both, higher and lower carbon stocks.
The review of accounting and reporting of organic soils shows that large discrepancies exist be-tween different sources of information regarding the extent of organic soils, their status and resulting emissions. Therefore, input data to MS’s GHG accounts needs to be improved. Comparisons with independent data sources can be useful for assessing the quality of GHG inventories for wetlands and organic soils.
Ecosystems provide multiple services that are necessary to maintain human life. Agroecosystems are very productive suppliers of biomass-related provisioning ecosystem services, e.g. food, fibre, and energy. At the same time, they are highly dependent on good ecosystem condition and regulating ecosystem services such as soil fertility, water supply or soil erosion regulation. Assessments of this interplay of ecosystem condition and services are needed to understand the relationships in highly managed systems. Therefore, the aim of this study is twofold: First, to test the concept and indicators proposed by the European Union Working Group on Mapping and Assessment of Ecosystems and their Services (MAES) for assessing agroecosystem condition at a regional level. Second, to identify the relationships between ecosystem condition and the delivery of ecosystem services. For this purpose, we applied an operational framework for integrated mapping and assessment of ecosystems and their services. We used the proposed indicators to assess the condition of agroecosystems in Northern Germany and regulating ecosystem service control of erosion rates. We used existing data from official databases to calculate the different indicators and created maps of environmental pressures, ecosystem condition and ecosystem service indicators for the Federal State of Lower Saxony. Furthermore, we identified areas within the state where pressures are high, conditions are unfavourable, and more sustainable management practices are needed.
Despite the limitations of the indicators and data availability, our results show positive, negative, and no significant correlations between the different pressures and condition indicators, and the control of erosion rates. The idea behind the MAES framework is to indicate the general condition of an ecosystem. However, we observed that not all proposed indicators can explain to what extent ecosystems can provide specific ecosystem services. Further research on other ecosystem services provided by agroecosystems would help to identify synergies and trade-offs. Moreover, the definition of a reference condition, although complicated for anthropogenically highly modified agroecosystems, would provide a benchmark to compare information on the condition of the ecosystems, leading to better land use policy and management decisions.
We compiled information from different sources in order to establish a comprehensive map of the stock of soil organic carbon (SOC) in the upper 30 cm under different forms of land use for Austria. The information serves as a baseline for the evaluation of the potential of climate-change mitigation measures. SOC sequestration plays an important role in the discussion of terrestrial carbon (C) sinks and the size of the SOC pool is one of several quality measures for crop production and the national and regional food security. The baseline serves also for the evaluation of the effectiveness of adaptive land management in order to cope with climate change. Austrian croplands, grasslands, forests, and settlements contain 300 Mt SOC. Peatlands have the highest SOC density (220 t C/ha), yet cover only about 2% of the country. Forest soils store 106 t C/ha and comprise the largest pool due to the coverage of more than 4 Mha (48% of the country). Intensively and extensively managed grasslands cover 0.8 Mha (10%) and contain between 91 and 113 t C/ha, and cropland on 1.28 Mha (15%) hold on average 62 t C/ha. Due to the geographic heterogeneity of Austria with respect to climatic conditions, geology and soils, and topography the regional differences in SOC stocks are large. Measures to increase the SOC stock in cropland have been applied for 25 years within agri-environmental and climate-smart strategies. An increase of the total SOC pool is expected due to the afforestation and reforestation of marginal agricultural land and to a smaller extent due to the restoration of peatlands. A decline of the SOC stock is a consequence of land development for settlements and infrastructure.
While agricultural systems are a major pillar in global food security, their productivity is currently threatened by many environmental issues triggered by anthropogenic climate change and human activities, such as land degradation. However, the planetary spatial footprint of land degradation processes on arable lands, which can be considered a major component of global agricultural systems, is still insufficiently well understood. This study analyzes the land degradation footprint on global arable lands, using complex geospatial data on certain major degradation processes, i.e. aridity, soil erosion, vegetation decline, soil salinization and soil organic carbon decline. By applying geostatistical techniques that are representative for identifying the incidence of the five land degradation processes in global arable lands, results showed that aridity is by far the largest singular pressure for these agricultural systems, affecting ∼40% of the arable lands’ area, which cover approximately 14 million km² globally. It was found that soil erosion is another major degradation process, the unilateral impact of which affects ∼20% of global arable systems. The results also showed that the two degradation processes simultaneously affect an additional ∼7% of global arable lands, which makes this synergy the most common form of multiple pressure of land degradative conditions across the world's arable areas. The absolute statistical data showed that India, the United States, China, Brazil, Argentina, Russia and Australia are the most vulnerable countries in the world to the various pathways of arable land degradation. Also, in terms of percentages, statistical observations showed that African countries are the most heavily affected by arable system degradation. This study’s findings can be useful for prioritizing agricultural management actions that can mitigate the negative effects of the two degradation processes or of others that currently affect many arable systems across the planet.
Detailed information on the spatio-temporal changes of cropland soil organic carbon (SOC) can significantly contribute to the improvement of soil fertility and mitigate climate change. Nonetheless, information and knowledge on the national scale spatio-temporal changes and the corresponding uncertainties of SOC in Chinese upland soils remain limited. The CENTURY model was used to estimate the SOC storages and their changes in Chinese uplands from 1980 to 2010. With the Monte Carlo method, the uncertainties of CENTURY-modelled SOC dynamics associated with the spatial heterogeneous model inputs were quantified. Results revealed that the SOC storage in Chinese uplands increased from 3.03 (1.59 to 4.78) Pg C in 1980 to 3.40 (2.39 to 4.62) Pg C in 2010. Increment of SOC storage during this period was 370 Tg C, with an uncertainty interval of −140 to 1110 Tg C. The regional disparities of SOC changes reached a significant level, with considerable SOC accumulation in the Huang-Huai-Hai Plain of China and SOC loss in the northeastern China. The SOC lost from Meadow soils, Black soils and Chernozems was most severe, whilst SOC accumulation in Fluvo-aquic soils, Cinnamon soils and Purplish soils was most significant. In modelling large-scale SOC dynamics, the initial soil properties were major sources of uncertainty. Hence, more detailed information concerning the soil properties must be collected. The SOC stock of Chinese uplands in 2010 was still relatively low, manifesting that recommended agricultural management practices in conjunction with effectively economic and policy incentives to farmers for soil fertility improvement were indispensable for future carbon sequestration in these regions.
The role of soils in the global carbon cycle and in reducing GHG emissions from agriculture has been increasingly acknowledged. The “4 per 1000” initiative (4p1000) has become a prominent action plan for climate change mitigation and achieve food security through an annual increase in soil organic carbon (SOC) stocks by 0.4 %, ( i.e. 4‰ per year). However, the feasibility of the 4p1000 scenario and, more generally, the capacity of individual countries to implement soil carbon sequestration (SCS) measures remain highly uncertain. Here, we evaluated country‐specific SCS potentials of agricultural land for 24 countries in Europe. Based on a detailed survey of available literature, we estimate that between 0.1 and 27 % of the agricultural greenhouse gas (GHG) emissions can potentially be compensated by SCS annually within the next decades. Measures varied widely across countries, indicating differences in country‐specific environmental conditions and agricultural practices. None of the countries’ SCS potential reached the aspirational goal of the 4p1000 initiative, suggesting that in order to achieve this goal, a wider range of measures and implementation pathways need to be explored. Yet, SCS potentials exceeded those from previous pan‐European modelling scenarios, underpinning the general need to include national/regional knowledge and expertise to improve estimates of SCS potentials. The complexity of the chosen SCS measurement approaches between countries ranked from tier 1 to tier 3 and included the effect of different controlling factors, suggesting that methodological improvements and standardisation of SCS accounting are urgently required. Standardisation should include the assessment of key controlling factors such as realistic areas, technical and practical feasibility, trade‐offs with other GHG and climate change. Our analysis suggests that country‐specific knowledge and SCS estimates together with improved data sharing and harmonisation are crucial to better quantify the role of soils in offsetting anthropogenic GHG emissions at global level.
It is essential to plug inefficiencies due to agrifood losses and wastes, which pose a significant threat to the sustainable supply of nutritional agrifood commodities/products. Country-specific evaluations of the extent of agrifood losses/wastes, including the pathways and impacts on net agrifood production, are crucial to inform interventions, research, policies and investments. This kind of knowledge is scarce in sub-Saharan Africa (SSA) countries, many of which are food insecure. This paper presents an estimation of and the bioenergy potential for agrifood loss and waste (AFW) – the edible and inedible residual biogenic fractions of crops and animal commodities/products – in Nigeria. Our findings reveal that Nigeria generates 183.3 ± 8.9MT of AFW per annum. About 27% of the average annual total domestic supply of edible agrifood commodities/products is lost before reaching markets/consumers. The intrinsic bioenergy potential of the inedible AFW fraction generated annually in Nigeria is estimated to be 1,816.8 ± 117.3PJ; this is sufficient to meet 2030's bioenergy targets and replace a third of its total (grid, off-grid and self-generation) supply targets. However, Nigeria lacks regulatory, policy and institutional frameworks specific to AFW management. This study recommends a sustainable approach to managing AFW, addressing the interlinked challenges of bioenergy production, public health and environmental sustainability. Besides addressing knowledge gaps in the Nigerian agrifood sector, the information generated in this study is well-timed to inform decision-making and policy formulation on decentralised AFW-based bioenergy interventions to achieve energy supply targets in the country by 2030 and beyond. This study is also strategic to guide future research/interventions that align with AFW utilisation/clean energy generation in SSA.
This chapter presents an overview of the Geospatial Analysis Approaches for Assessing Biomass Potentials from Agricultural Landscapes. The chapter begins with a discussion about the sustainability challenges and opportunities for assessing the biomass resources potentials, tackling the main sustainability aspects linked to the use of agricultural biomass for energy, competition for land and other resources, the impact on land as well as the ways for addressing uncertainty risks and benefits for bioenergy. This information provides the basis for a detailed analysis of the geospatial methods used for assessing the bioenergy potentials in agricultural landscapes, especially for energy crops and agricultural residues. The section describes different approaches that employing different methodologies, from simple statistical to more complex spatially explicit methods and integrated modelling assessments. Depending on the focus and constraints adopted, the results can be expressed as Theoretical, Technical, Economic, Environmental and/or Sustainable potentials. Following the resource assessment section, the techniques used for estimating the energy potential of biomass resources are described. The common approach is to simulate a combination of facilities that consume and transform the biomass resources into energy products (biofuels, electricity, heat, etc.). In this regard, there are two main types of methodological approaches: suitability and optimality analyses. The suitability analysis, based on multi-criteria evaluation, encompasses a collection of procedures for solving problems based on multiple rules or criteria. The suitability analysis relies on heuristic algorithms to satisfy the location-allocation problems, which are used to identify optimal locations for bioenergy plants taking into consideration the availability of feedstock (supply), the transportation network, and the customer’s needs for energy (demand). In combination, these methods can provide geospatial information about the bioenergy potential in agricultural landscapes.
Purpose
To achieve the dual goals of decarbonization and food security, this paper examines China's carbon footprint reduction in 2050 based on current mitigation strategies.
Design/methodology/approach
Considering publications as featured evidence, this study develops an investigation of agricultural decarbonization in China. First, the authors summarize the mitigation strategies for agricultural greenhouse gas (GHG) emissions in the existing literature. Second, the authors demonstrate the domestic food production target in 2050 and the projection target's projected life-cycle-based GHG emissions at the commodity level. Lastly, the authors forecast China's emission removal in the agri-food sector in 2050 concerning current mitigation strategies and commodity productions. The authors highlight the extent to which each mitigation strategy contributes to decarbonization in China.
Findings
Practices promoting sustainable development in the agri-food sector significantly contribute to GHG emission removal. The authors find mitigation strategies inhibiting future GHG emissions in the agri-food sector comprise improving nitrogen use efficiency in fertilizers, changing food consumption structure, manure management, cover crops, food waste reduction, dietary change of livestock and covered manure. A 10% improvement in nitrogen use efficiency contributes to 5.03% of GHG emission removal in the agri-food sector by 2050. Reducing food waste and food processing from 30% to 20% would inhibit 1.59% of the total GHG emissions in the agri-food sector.
Originality/value
This study contributes to policy discussions by accounting for agricultural direct and indirect emission components and assessing the dynamic changes in those related components. This study also extends existing research by forecasting to which extent the decarbonization effects implemented by current mitigation strategies can be achieved while meeting 2050 food security in China.
Soil organic carbon plays a major role in the global carbon budget, and can act as a source or a sink of atmospheric carbon, thereby possibly influencing the course of climate change. Changes in soil organic carbon (SOC) stocks are now taken into account in international negotiations regarding climate change. Consequently, developing sampling schemes and models for estimating the spatial distribution of SOC stocks is a priority. The French soil monitoring network has been established on a 16 km × 16 km grid and the first sampling campaign has recently been completed, providing around 2200 measurements of stocks of soil organic carbon, obtained through an in situ composite sampling, uniformly distributed over the French territory.
We calibrated a boosted regression tree model on the observed stocks, modelling SOC stocks as a function of other variables such as climatic parameters, vegetation net primary productivity, soil properties and land use. The calibrated model was evaluated through cross-validation and eventually used for estimating SOC stocks for mainland France. Two other models were calibrated on forest and agricultural soils separately, in order to assess more precisely the influence of pedo-climatic variables on SOC for such soils.
The boosted regression tree model showed good predictive ability, and enabled quantification of relationships between SOC stocks and pedo-climatic variables (plus their interactions) over the French territory. These relationships strongly depended on the land use, and more specifically, differed between forest soils and cultivated soil. The total estimate of SOC stocks in France was 3.260 ± 0.872 PgC for the first 30 cm. It was compared to another estimate, based on the previously published European soil organic carbon and bulk density maps, of 5.303 PgC. We demonstrate that the present estimate might better represent the actual SOC stock distributions of France, and consequently that the previously published approach at the European level greatly overestimates SOC stocks.
We use a soil carbon (C) model (RothC), driven by a range of climate models for a range of climate scenarios to examine the impacts of future climate on global soil organic carbon (SOC) stocks. The results suggest an overall global increase in SOC stocks by 2100 under all scenarios, but with a different extent of increase among the climate model and emissions scenarios. The impacts of projected land use changes are also simulated, but have relatively minor impacts at the global scale. Whether soils gain or lose SOC depends upon the balance between C inputs and decomposition. Changes in net primary production (NPP) change C inputs to the soil, whilst decomposition usually increases under warmer temperatures, but can also be slowed by decreased soil moisture. Underlying the global trend of increasing SOC under future climate is a complex pattern of regional SOC change. SOC losses are projected to occur in northern latitudes where higher SOC decomposition rates due to higher temperatures are not balanced by increased NPP, whereas in tropical regions, NPP increases override losses due to higher SOC decomposition. The spatial heterogeneity in the response of SOC to changing climate shows how delicately balanced the competing gain and loss processes are, with subtle changes in temperature, moisture, soil type and land use, interacting to determine whether SOC increases or decreases in the future. Our results suggest that we should stop looking for a single answer regarding whether SOC stocks will increase or decrease under future climate, since there is no single answer. Instead, we should focus on improving our prediction of the factors that determine the size and direction of change, and the land management practices that can be implemented to protect and enhance SOC stocks.
Executive summary
The European Commission has recently adopted the Thematic Strategy for soil protection
(COM(2006)231 final), with the objective to ensure that Europe’s soils remain healthy
and capable of supporting human activities and ecosystems. Climate change is identified
as a common element in many soil threats. Therefore the Commission intends to assess
the actual contribution of the protection of soil to climate change mitigation and the
effects of climate change on soil productivity and the possible depletion of soil organic
matter as result of climate change. The objective of this study is to provide a state of the
art and more robust understanding of interactions between soil under different land uses
and climate change than is available now, through a comprehensive literature review and
expert judgment.
1 Carbon stock in EU soils
The amount of carbon in European soils is estimated to be equal to 73 to 79 billion
tonnes. These estimates are based on applying a common methodology across Europe,
the larger estimate was based on a method developed by the Joint Research Centre of the
European Commission and the smaller estimate on a soil organic carbon (SOC) map of
the United States Department of Agriculture. These two methodologies gave similar
estimates for most of the European countries. The estimates were of the same order of
magnitude as national estimates based on national methodologies and are therefore
deemed reliable.
Carbon in EU27 soils is concentrated in specific regions: roughly 50% of the total carbon
stock is located in Sweden, Finland and the United Kingdom (because of the vast area of
peatlands in these countries) and approximately 20% of the carbon stock is in peatlands
mainly in the northern parts of Europe. The rest of soil C is in mineral soils, again the
higher amount being in northern Europe.
2 Soils sink or source for CO2 in the EU
Uptake of carbon dioxide (CO2) through photosynthesis and plant growth and loss
(decomposition) of organic matter from terrestrial ecosystems are both significant fluxes
in Europe. Yet, the net terrestrial carbon fluxes (uptake of CO2 minus respiration by
vegetation and soils) are typically smaller relative to the emissions from use of fossil fuel.
The current changes in the carbon pool of the European soils were estimated from
different studies using different methods, by land use category using models that simulate
carbon cycling in soil. The results of the different studies deviated considerably from
each other, and all results were accompanied with wide uncertainty ranges. Some studies
on the basis of measurements in UK, Belgium and France on soil carbon over longer
periods show losses of carbon especially from cropland; other studies from the UK and
from the Netherlands show no change or increases in soil carbon stocks over time.
Grassland soils were found in all studies to generally accumulate carbon. However, the
studies differ on the amount of carbon accumulated. In one study, the sink estimate
ranged from 1 to 45 million tonnes of carbon per year and, in another study, the mean
estimate was 101 million tonnes per year, although with a high uncertainty.
Cropland generally acts as a carbon source, although existing estimates vary highly. In
one study, the carbon balance estimates of croplands ranged from a carbon sink equal to
10 million tonnes of carbon per year to a carbon source equal to 39 million tonnes per
year. In another study, croplands in Europe were estimated to be losing carbon up to 300
million tonnes per year. The latter is now perceived as a gross overestimation.
Forest soils generally accumulate carbon in each European country. Estimates range
from 17 to 39 million tonnes of carbon per year with an average of 26 million tonnes per
year in 1990 and to an average of 38 million tons of carbon per year in 2005.
It would seem that on a net basis, soils in Europe are on average most likely accumulating
carbon. However, given the very high uncertainties in the estimates for cropland and
grassland, it would not seem accurate and sound to try to use them to aggregate the data
and produce an estimate of the carbon accumulation and total carbon balance in European
soils.
3 Peat and organic soils
The current area of peat occurrence in the EU Member States and Candidate Countries is
over 318 000 km2. More than 50% of this surface is in just a few northern European
countries (Norway, Finland, Sweden, United Kingdom); the remainder in Ireland, Poland
and Baltic states. Of that area, approximately 50% has already been drained, while most
of the undrained areas are in Finland and Sweden.
Although there are gaps in information on land use in peatlands, it can be estimated that
water saturated organic rich soil (peatland) have been drained for:
- agriculture – more than 65 000 km2 (20% of the total European peatland area);
- forestry – almost 90 000 km2 (28%);
- peat extraction – only 2 273 km2 (0.7%).
This is important as the largest emissions of CO2 from soils are resulting from land use
change and related drainage of organic soils and amount to 20-40 tonnes of CO2 per
hectare per year. The emission from cultivated and drained organic soils in EU27 is
approximately 100 Mt CO2 per year. Peat layer have been lost by oxidation during land
use, but the estimate derivable from the published data, ca. 18 000 km2, is very probably
an underestimate.
4 Land use and soil carbon
Monitoring programs, long term experiments and modelling studies all show that land use
significantly affects soil carbon stocks. Soil carbon losses occur when grasslands,
managed forest lands or native ecosystems are converted to croplands. Vice versa soil
carbon stocks are restored when croplands are either converted to grasslands, forest lands or natural ecosystems. Conversion of forest lands into grasslands does not affect soil carbon in all cases, but does reduce total ecosystem carbon due to the removal of
aboveground biomass.
The more carbon is present on the soil, the higher the potential for losing it. Therefore the
potential losses of unfavourable land use changes on highly organic peat soils are a major risk. The most effective strategy to prevent global soil carbon loss would be to halt land conversion to cropland, but this may conflict with growing global food demand unless
per-area productivity of the cropland continues to grow.
5 Soil management and soil carbon
Soil management practices are an important tool to affect the soil carbon stocks. Suitable
soil management strategies have been identified within all different land use categories
and are available and feasible to implement. These are:
- On cropland, soil carbon stocks can be increased by
(i) agronomic measures that increase the return of biomass carbon to the soil,
(ii) tillage and residue management,
(iii) water management,
(iv) agro-forestry.
- On grassland, soil carbon stocks are affected by
(i) grazing intensity
(ii) grassland productivity,
(iii) fire management and
(iv) species management.
- On forest lands, soil carbon stocks can be increased by
(i) species selection,
(ii) stand management,
(iii) minimal site preparation,
(iv) tending and weed control,
(v) increased productivity,
(vi) protection against disturbances and
(vii) prevention of harvest residue removal.
- On cultivated peat soils the loss of soil carbon can be reduced by
(i) higher ground water tables.
- On less intensively / un-managed heathlands and peatlands, soil carbon stocks
are affected by
(i) water table (drainage),
(ii) pH (liming), fertilisation,
(iii) burning
(iv) grazing.
- On degraded lands, carbon stocks can be increased after restoration to a
productive situation.
Given that land use change is often driven by demand and short term economic revenues,
the most realistic option to improve soil carbon stocks is to a) protect the carbon stocks in
highly organic soils such as peats mostly in northern Europe, and b) to improve the way
in which the land is managed to maximise carbon returns to the soil and minimise carbon
losses. Increased nitrogen fertilizer use has made a large contribution to the growth in
productivity, but further increased use will lead to greater emissions of nitrous oxide
(N2O). Hence future emphasis should be concentrated on the other main driver of
productivity, i.e. improved crop varieties.
6 Carbon sequestration
Soils contain about three times the amount of carbon globally as vegetation, and about
twice that in the atmosphere. There is a significant and large uncertainty associated with
the response of soil carbon (and other pools of biospheric carbon) to future climate
changes. Most response are calculated with simulation models with some models
predicting large releases of additional carbon from soils and vegetation under climate
change, and others suggesting only small feedback. The maximum possible amount of
carbon that soil sequestration could achieve is about one third of the current yearly
increase in atmospheric carbon (as carbon dioxide) stocks. This is about one seventh of
yearly anthropogenic carbon emissions of 7500 Mt C. In Europe emissions of greenhouse
gases amount to approximately 4100 Mt CO2 (or 1000 Mt C) per year.
Today, soils in Europe are most likely a sink and the best estimate is that they sequester
up to 100 Mton C per year. Higher sequestration is possible with adequate soil
management. Soil C-sequestration alone is surely no ‘golden bullet’ to fight climate
change but is it realistic to link climate change with soil carbon conservation, as soil
carbon sequestration is cost competitive, of immediate availability, does not require the
development of new and unproven technologies, and provides comparable mitigation
potential to that available in other sectors.
Therefore, given that climate change needs to be tackled urgently if atmospheric carbon
dioxide concentrations are to be stabilized below levels thought to be irreversible, soil
carbon sequestration or the even more effective conservation of current carbon stocks in
soils has a key role to play in any raft of measures used to tackle climate change.
7 Effects of climate change on soil carbon pools
We have not found strong and clear evidence for either an overall combined positive or
negative impact of climate change (raised atmospheric CO2 concentration, temperature,
precipitation) on terrestrial carbon stocks. There are suggestions for enhancing soil C
stocks at higher atmospheric CO2 concentration and reducing soil C stocks when
temperatures are rising. Most studies have taken moderate changes in temperature
increases and sudden and more severe changes in temperature of precipitation have not
been considered, as the management of land and soils overrules any impact on soil carbon from climate change.
All of the factors of climate change (raised atmospheric CO2 concentration, temperature,
precipitation) affect soil C, with the effect on soils of CO2 being indirect (through
photosynthesis) and the effects of weather factors being both direct and indirect. Climate
change affects soil carbon pools by affecting each of the processes in the C-cycle:
photosynthetic C-assimilation, litter fall, decomposition, surface erosion, hydrological
transport. Due to the relatively large gross exchange of CO2 between atmosphere and
soils and the significant stocks of carbon in soils, relatively small changes in these large
but opposing fluxes of CO2 may have significant impact on our climate and on soil
quality. Therefore, managing these fluxes (through proper soil management) can help
mitigate climate change considerably.
8 Monitoring systems for changes in soil carbon
Today, monitoring and knowledge on land use and land use change in EU27 is
insufficient, yet land use and land use change are a key source of greenhouse gas
emissions in many of the EU27 member states. Soil monitoring in EU27 seems like the
Tower of Babel: countries tend to have their own systems, if any, sometimes even more
than one system, and the results are not fully compatible across EU27. The few existing
systems tend to have been set up for different purposes, often not including that of
providing evidence concerning the impact of climate change on soil carbon pools. This
19
lack of systematic and comparable data gathering and analyses seriously hampers any
attempt to provide reliable, EU-wide data on the soil carbon stock and changes therein.
Moreover, the new goal of monitoring stock-changes rather than stock-magnitudes may
necessitate significant changes to current soil sampling procedures.
Given the lack of reliable national monitoring systems and without an EU wide
harmonized system of monitoring of soil carbon in place, it would be a significant
advance if the EU were to ask for a design or initiate implementation of a harmonized
EU27 monitoring for land uses and for specific activities that affect soil carbon stocks
and emissions of CO2. Such monitoring would also allow for adequate representation of
changes in soil carbon in EU27 in reporting to the United Nations Framework
Convention to Combat Climate Change (UNFCCC).
9 EU policies and soil carbon
We have critically reviewed EU policies that are likely to have impacts on soil carbon (C)
to assess whether any of those policies might have adverse impacts on soil C in the long
term. Policies reviewed were the Common Agricultural Policy (CAP), the Nitrates
Directive, the Renewable Energy Sources Directive, the Biofuels Directive, Waste policy
and the EU Thematic Strategy for soil protection.
Legislation to encourage the production of arable crops to provide feed stocks for
renewable energy is perhaps the legislation most likely to lead to decreases in the overall
carbon content of European soils. While studies may indicate much of the demand may
be met by imports from outside the EU, and hence may have little impacts on soil C
within the EU, there may be serious implications for soil C stocks in those countries
which supply renewable energy or their substrates.
We conclude that the need to comply with environmental requirements under the Cross
Compliance requirement of CAP is an instrument that may be used to maintain SOC. The
measures required under UNFCCC are not likely to adversely impact soil C. Nor are
there any measures in the proposed Soil Framework Directive that would be expected to
lead to decreases on soil C.
Process-based soil organic C (SOC) models are widely used for simulating, monitoring, and verifying soil C change. In such models, determining the initial distribution of SOC across multiple pools is oft en not well defined, yet pool initialization can strongly influence the subsequent SOC dynamics. We developed a model-based procedure to initialize SOC fractions that uses site-specific soil, climatic, and land use history information, along with measured initial total SOC, to estimate SOC distribution across pools. The procedure consists of creating sets of SOC fractions for scenarios including different field histories, soil texture, and management practices for medium-and long-term simulations to provide a broad spectrum of conditions, using data from an experimental site in Georgia. Tables created using this procedure can help model users select the SOC fractions needed to properly initialize the model. The model is executed for the duration of the prior land use history time period, and the simulated final total SOC is compared with the soil C measurement at the beginning of the subsequent experimental time period. If these values are equal, the final SOC fractions from the land use history simulations are used with the measured soil C to start the simulation of the cropping system being studied. If these values are not equal, then the procedure is repeated iteratively until the measured value of soil C is adequately predicted. We demonstrated the improved prediction accuracy by using the proposed procedure in simulating soil C for a long-term field experiment in Michigan.
Climate change is projected to significantly impact vegetation and soils of managed ecosystems. In this study we used the
ecosystem Century model together with climatic outputs from different atmosphere-ocean general circulation models (AOGCM)
to study the effects of climate change and management on soil organic carbon (SOC) dynamics in semiarid Mediterranean conditions
and to identify which management practices have the greatest potential to increase SOC in these areas. Five climate scenarios
and seven management scenarios were modeled from 2010 to 2100. Differences in SOC sequestration were greater among management
systems than among climate change scenarios. Management scenarios under continuous cropping yielded greater C inputs and SOC
gain than scenarios under cereal-fallow rotation. The shift from rainfed conditions to irrigation also resulted in an increase
of C inputs but a decrease in the SOC sequestered during the 2010-2100 period. The effects of precipitation and temperature
change on SOC dynamics were different depending on the management system applied. Consequently, the relative response to climate
and management depended on the net result of the influences on C inputs and decomposition. Under climate change, the adoption
of certain management practices in semiarid Mediterranean agroecosystems could be critical in maximizing SOC sequestration
and thus reducing CO2 concentration in the atmosphere.
Regional climate change projections based on dynamic downscaling through regional climate models are used to assess drought frequency, intensity and duration, and the impact propagation from meteorological, hydrological and agricultural sectors. The impact on a meteorological drought index (standardized precipitation index, SPI) is first assessed based on daily climate inputs from RCMs driven by three general circulation models (GCMs) (PCM, HadCM3, CCSM3) with different climate sensitivities. Two emission scenarios, relatively high and low emission, are undertaken for each of the three GCMs and dynamically downscaled through the RCMs. Feeding the climate projections to a calibrated hydro-agronomic model at the watershed scale in Central Illinois, hydrological drought (standardized runoff index, SRI) and agricultural drought (standardized soil water index, SSWI) indices and the economic impacts are assessed. RCMs driven by different GCMs predict different changes of drought properties. From the intensity-density-frequency (IDF) curves of SPI, SSWI, and SRI based on the three GCM-RCMs, as expected, the return period increases with the increase of drought duration for a given drought intensity. However, the change of IDF curves from baseline to future years varies with GCM-RCM and drought indicator. HadCM3-RCM predicts moderate increase of drought frequency and CCSM3-RCM predicts significant increase of drought frequency especially for the SSWI and SRI with moderate drought intensity (I
This paper investigates the impact of climate change on drought by addressing two questions: (1) How reliable is the assessment of climate change impact on drought based on state-of-the-art climate change projections and downscaling techniques? and (2) Will the impact be at the same level from meteorological, agricultural, and hydrologic perspectives? Regional climate change projections based on dynamical downscaling through regional climate models (RCMs) are used to assess drought frequency, intensity, and duration, and the impact propagation from meteorological to agricultural to hydrological systems. The impact on a meteorological drought index (standardized precipitation index, SPI) is first assessed on the basis of daily climate inputs from RCMs driven by three general circulation models (GCMs). Two periods and two emission scenarios, i.e., 1991-2000 and 2091-2100 under B1 and A1Fi for Parallel Climate Model (PCM), 1990-1999 and 2090-2099 under A1B and A1Fi for Community Climate System Model, version 3.0 (CCSM3), 1980-1989 and 2090-2099 under B2 and A2 for Hadley Centre CGCM (HadCM3), are undertaken and dynamically downscaled through the RCMs. The climate projections are fed to a calibrated hydro-agronomic model at the watershed scale in Central Illinois, and agricultural drought indexed by the standardized soil water index (SSWI) and hydrological drought by the standardized runoff index (SRI) and crop yield impacts are assessed. SSWI, in particular with extreme droughts, is more sensitive to climate change than either SPI or SRI. The climate change impact on drought in terms of intensity, frequency, and duration grows from meteorological to agricultural to hydrological drought, especially for CCSM3-RCM. Significant changes of SSWI and SRI are found because of the temperature increase and precipitation decrease during the crop season, as well as the nonlinear hydrological response to precipitation and temperature change.
We use a soil carbon (C) model (RothC), driven by a range of climate models for a range of climate scenarios to examine the impacts of future climate on global soil organic carbon (SOC) stocks. The results suggest an overall global increase in SOC stocks by 2100 under all scenarios, but with a different extent of increase among the climate model and emissions scenarios. The impacts of projected land use changes are also simulated, but have relatively minor impacts at the global scale. Whether soils gain or lose SOC depends upon the balance between C inputs and decomposition. Changes in net primary production (NPP) change C inputs to the soil, whilst decomposition usually increases under warmer temperatures, but can also be slowed by decreased soil moisture. Underlying the global trend of increasing SOC under future climate is a complex pattern of regional SOC change. SOC losses are projected to occur in northern latitudes where higher SOC decomposition rates due to higher temperatures are not balanced by increased NPP, whereas in tropical regions, NPP increases override losses due to higher SOC decomposition. The spatial heterogeneity in the response of SOC to changing climate shows how delicately balanced the competing gain and loss processes are, with subtle changes in temperature, moisture, soil type and land use, interacting to determine whether SOC increases or decreases in the future. Our results suggest that we should stop looking for a single answer regarding whether SOC stocks will increase or decrease under future climate, since there is no single answer. Instead, we should focus on improving our prediction of the factors that determine the size and direction of change, and the land management practices that can be implemented to protect and enhance SOC stocks.
Export Date: 2 January 2013, Source: Scopus, Article in Press
This report assesses the effects of aircraft on climate and atmospheric ozone and is the first IPCC report for a specific industrial subsector. It was prepared by IPCC in collaboration with the Scientific Assessment Panel to the Montreal Protocol on Substances that Deplete the Ozone Layer, in response to a request by the International Civil Aviation Organization (ICAO) because of the potential impact of aviation emissions. These are the predominant anthropogenic emissions deposited directly into the upper troposphere and lower stratosphere.
Aviation has experienced rapid expansion as the world economy has grown. Passenger traffic (expressed as revenue passenger kilometers) has grown since 1960 at nearly 9% per year, 2.4 times the average Gross Domestic Product (GDP) growth rate. Freight traffic, approximately 80% of which is carried by passenger airplanes, has also grown over the same time period. The rate of growth of passenger traffic has slowed to about 5% in 1997 as the industry is maturing. Total aviation emissions have increased, because increased demand for air transport has outpaced the reductions in specific emissions3 from the continuing improvements in technology and operational procedures. Passenger traffic, assuming unconstrained demand, is projected to grow at rates in excess of GDP for the period assessed in this report.
The effects of current aviation and of a range of unconstrained growth projections for aviation (which include passenger, freight, and military) are examined in this report, including the possible effects of a fleet of second generation, commercial supersonic aircraft. The report also describes current aircraft technology, operating procedures, and options for mitigating aviation's future impact on the global atmosphere. The report does not consider the local environmental effects of aircraft engine emissions or any of the indirect environmental effects of aviation operations such as energy usage by ground transportation at airports.
In 1999 no-tillage farming, synonymous of zero tillage farming or conservation agriculture, was adopted on about 45 million ha world wide, growing to 72 million ha in 2003 and to 111 million ha in 2009, corresponding to an growth rate of 6 million ha per annum. Fastest adoption rates have been experienced in South America where some countries are using no-tillage farming on about 70% of the total cultivated area. Opposite to countries like the USA where often fields under no-tillage farming are tilled every now and then, more than two thirds of the area under no-tillage systems in South America is permanently not tilled; in other words once adopted, the soil is never tilled again. The spread of no-tillage systems on more than 110 million ha world-wide shows the great adaptability of the systems to all kinds of climates, soils and cropping conditions. No-tillage is now being practiced from the artic circle over the tropics to about 50ºlatitude south, from sea level to 3,000 m altitude, from extremely rainy areas with 2,500 mm a year to extremely dry conditions with 250 mm a year. No-till farming offers a way of optimizing productivity and ecosystem services, offering a wide range of economic, environmental and social benefits to the producer and to the society. At the same time, no-till farming is enabling agriculture to respond to some of the global challenges associated with climate change, land and environmental degradation, and increasing cost of food, energy and production inputs. The wide recognition of no-till farming as a truly sustainable system should ensure the spread of the no-till technology and the associated practices of organic soil cover and crop rotation, as soon as the barriers to its adoption have been overcome, to areas where adoption is currently still low. The widespread adoption globally also shows that no-tillage farming cannot any more be considered a temporary fashion or a craze; instead largely through farmers'own effort, the system has established itself as a farming practice and a different way of thinking about sustainable agro-ecosystem management that can no longer be ignored by scientists, academics, extension workers, farmers at large as well as equipment and machine manufacturers and politicians.. Current status of adoption of no-till farming in the world and some of its main benefits. Int J Agric & Biol Eng, 2010; 3(1): 1－25.
The aim of this work was to quantify the soil organic C (SOC) stock in the top 30 cm of mineral soil for the whole Italian territory, according to the different land use types of the Intergovernmental Panel on Climate Change (IPCC) cropland category (arable land, agroforestry, vineyards, olive groves, orchards and rice fields), as a basis for future land use scenarios and to address mitigation policy at country level. A database for SOC stock was created with the data from the national project denominated SIAS and partly from regional map reports. All data were referred to the year 2000 since they were derived from surveys conducted from 1995 to 2005. The data were stratified according to the Italian climatic regions, the landscape position and the IPCC cropland subcategories. Taking into account the uncertainty in the estimate, the mean SOC stock values of the different subcategories show significant differences (p<0.05) among climatic regions and landscapes, ranging from 41.9± 15.9 Mg C ha −1 in the vineyards to 63.3±27.9 Mg C ha −1 in the rice fields. Generally, a small decrease of the SOC stock from the temperate regions toward the Mediterranean ones is observed. Taking into account the mean value of each subcategory and the country area they occupied in 2000, the total C stored in the upper 30 cm of soil was estimated at 490.0±121.7 Tg C. The resulting estimate represents the 17% of the value reported by another study for the soil of the whole country down to 50 cm depth, suggesting the importance of preserving this large C pool. Considering the cropland category as a whole, the estimated mean SOC stock is 52.1±17.4 Mg C ha −1 , similar to that reported for other European countries, 50–60 Mg C ha −1 . In conclusion, the assessment of the mean SOC stock of the different cropland land uses, landscape position and climate regions could notably help when assessing the impact of different agricultural practices and future stock change evaluation.
Soil organic carbon (SOC) storage is an indicator of environmental quality for mineral soils because of the influence that organic matter has on key functional properties, such as fertility, soil structure and water relations. Historically, agricultural management has caused large losses of SOC relative to native ecosystems, leading to degradation. However, new technologies and conservation practices have been developed during the past few decades that can enhance SOC storage, and thus improve environmental quality. Our objective was to describe a national inventory procedure to estimate SOC storage for purposes of monitoring environmental quality. The major steps in this procedure include: (1) model selection/development, (2) model verification, (3) identification of model input data, (4) uncertainty assessment, (5) model implementation, and (6) validation of results. Applying this approach with a simple C accounting method, the upper 30 cm of US agricultural soils were estimated to have accumulated 10.8 Tg C yr-1 between 1982 and 1997, with an uncertainty of ± 40%. A simple index was developed to relate estimated SOC stocks to the potential amounts under native conditions and conventional agricultural management. An index value of 0% on the proposed scale would be equivalent to the SOC under conventional agricultural use, while an index value of 100% would be equivalent to native levels. With an estimated 1997 stock of 22 400 Tg C, the index value for US agricultural soils was about 60%. Using this inventory procedure, environmental issues related to soil, water and air quality could be informed by SOC in combination with other key indicators, in addition to using the inventory for evaluating sustainability of agricultural lands for food and fiber production.
Carbon (C) sequestration in soil implies transfer and secure storage of atmospheric CO2 into the soil organic carbon (SOC) pool as recalcitrant humus/biochar and into the soil inorganic carbon (SIC) pool as secondary carbonates. Its importance lies in the urgent need to offset increases in atmospheric enrichment of CO2 (from 280 ppm in 1750 to 385 ppm in 2008) and its benefits to agronomic yield and soil quality. The soil C sink capacity, created by historic land use and soil degradation, is estimated at 78±12 Pg or 10-60 Mg/ha (Lal, 1999). Principal strategies of SOC sequestration involve: (i) restoration of degraded/desertified soils through conversion to a perennial land use, and (ii) adoption of recommended management practices including no-till farming, manuring, agroforestry and use of biochar as a soil amendment. The mean rate of C sequestration is 300-500 kg/ha/yr for SOC and 2-10 kg/ha/yr for SIC. Accelerated soil erosion is a net source of atmospheric CO2 and must be effectively controlled. Soil C sequestration is also enhanced by adoption of nanotechnology, biotechnology, information technology and trading of C credits. Avoidance of deforestation, and afforestation of degraded/desertified soils are cost-effective and have a large potential to offset emissions, influence the global C cycle and stabilize the atmospheric CO2. Soil C sequestration is a win-win-win strategy because it advances food security, improves the environment and mitigates global warming.
In December 1997, in Kyoto, Japan, over 160 parties to the 1992 United Nations Framework Convention on Climate Change (FCCC or Convention) adopted the Kyoto Protocol, which, for the first time, establishes legally binding limits for industrialized countries on emissions of carbon dioxide and other “greenhouse gases.” The Kyoto Protocol (the Protocol) is quite complex, reflecting the complicated political, economic, scientific and legal issues raised by human-induced climate change. The result of more than two years of preparatory discussions and eleven days of often-intense negotiations in Kyoto, the Protocol will be opened for signature in March 1998 for one year, although countries may accede to it after that period. It will enter into force ninety days after at least fifty-five parties to the FCCC, encompassing FCCC Annex I parties that accounted in total for at least 55 percent of the total emissions for 1990 of carbon dioxide (CO 2 ) of Annex I parties, have ratified, accepted, approved or acceded to the Protocol.
Currently, there is little information about soil organic carbon (SOC) stocks and changes in Mediterranean areas at a regional scale. We modelled an area of 95 269 km2 in northeast Spain using the Global Environmental Facility Soil Organic Carbon (GEFSOC) system to predict SOC stocks and changes in pasture, forest and agricultural soils. The spatial distribution of the different land‐use categories and their change over time was obtained by using the Corine database and official Spanish statistics on land use from 1926 to 2007. The model predicted the largest current SOC stock in forest soils at 578 Tg C. Agricultural soils were the second largest SOC reservoir, containing 244 Tg C. During the last 30 years, the model predicted a total SOC gain in the 0–30‐cm soil layer of 34 Tg C. Forest and grassland‐pasture soils had a decline in their stored SOC of 5 and 3 Tg C, respectively, because of the reduction in the soil surface occupied by both classes. The greatest SOC gain was predicted in agricultural soils with 42 Tg C caused by changes in management, which led to increases in C inputs. Although model uncertainty was not quantified, some hypothetical assumptions about the initialization and parameterization of the model could be potential sources of uncertainty. Our simulations predicted that in northeast Spain soil management has contributed to the sequestration of substantial amounts of atmospheric CO2 during the last 30 years. More research is needed in order to study the potential role of soils as atmospheric CO2 sinks under different managements and climatic conditions.
The lack of comprehensive data on the bulk density of soil types at the European scale is a serious limitation for pan‐European environmental risk assessment studies. Although many predictive methods have been published, most have limitations for application across Europe. We therefore developed a semi‐empirical method of prediction using a large UK dataset and tested it and some other methods against a pan‐European dataset. Our method indicated that five separate conceptual groupings of the development dataset were valid. Predictive equations based on multiple regression analysis for each of the five groups explained between 40 and 69% of the measured variation in each one. When used to predict measured bulk density from the European dataset, the equations explained 63% of the measured variation in mineral horizons from soil environments similar to those of the development dataset with a predictive mean percentage error of ±11%. The equation for organic horizons explained 29% of the measured variation in bulk density with a mean percentage error of ±39%. For those horizons from soil environments outside those of the development dataset, prediction of bulk density was relatively poor, even when using soil region‐specific PTFs derived from its data. It was concluded that, for these soils, factors other than organic carbon, particle size, horizon depth, mechanical cultivation or parent material have a major influence on bulk density and need further investigation.
The Summary for Policy Makers of the IPCC Special Report on Managing the
Risks of Extreme Events and Disasters to Advance Climate Change
Adaptation will be approved by the world governments in November 2011.
The focus of the Special Report is on climate change and its role in
altering the frequency, severity, and impact of extreme events or
disasters, and on the costs of both impacts and the actions taken to
prepare for, respond to, and recover from extreme events and disasters.
The emphasis is on understanding the factors that make people and
infrastructure vulnerable to extreme events, on recent and future
changes in the relationship between climate change and extremes, and on
managing the risks of disasters over a wide range of spatial and
temporal scales. The assessment considers a broad suite of adaptations
and explores the limits to adaptation. The assessment was designed to
build durable links and foundations for partnerships between the
stakeholder communities focused on climate change and those focused on
disaster risk reduction. The Special Report begins with material that
frames the issues, followed by an assessment of the reasons that
communities are vulnerable. Two chapters assess the role of past and
future climate change in altering extremes and the impact of these on
the physical environment and human systems. Three chapters assess
available knowledge on impacts and adaptation, with separate chapters
considering the literature, stakeholder relationships, and potential
policy tools relevant to the local, national, and international scales.
Longer-term components of adaptation to weather and climate extremes and
disasters are assessed in the context of moving toward sustainability.
The final chapter provides case studies that integrate themes across
several chapters or are so unique that they need to be considered
separately.
Soils contain vast reserves (similar to 1500 Pg C) of carbon, about twice that found as carbon dioxide in the atmosphere. Historically, soils in managed ecosystems have lost a portion of this carbon (40-90 Pg C) through land use change, some of which has remained in the atmosphere. In terms of climate change, most projections suggest that soils carbon changes driven by future climate change will range from small losses to moderate gains, but these global trends show considerable regional variation. The response of soil C in future will be determined by a delicate balance between the impacts of increased temperature and decreased soil moisture on decomposition rates, and the balance between changes in C losses from decomposition and C gains through increased productivity. In terms of using soils to mitigate climate change, soil C sequestration globally has a large, cost-competitive mitigation potential. Nevertheless, limitations of soil C sequestration include time-limitation, non-permanence, displacement and difficulties in verification. Despite these limitations, soil C sequestration can be useful to meet short-term to medium-term targets, and confers a number of co-benefits on soils, making it a viable option for reducing the short term atmospheric CO2 concentration, thus buying time to develop longer term emission reduction solutions across all sectors of the economy.
This paper focuses on the conceptual basis for recent changes to the CENTURY soil organic matter (SOM) model. Model predictions are compared on the effect of soil texture on total soil C levels and turnover rates of C in different pools, short-term (1-2 yr) dynamics of added plant residue, and loss of soil C due to cultivation with observation. Modeling studies of the long-term impact of different crop management practices on soil C and N stabilization were also summarized for sites at Pendleton, Oregon, Sidney, Nebraska and in Sweden. The model was used to interpret observed long-term soil C data sets, to highlight uncertainties in understanding about SOM dynamics and to suggest research topics that are critical for advancing knowledge about SOM. -from Authors
The interactive effects of climate change and atmospheric CO2 rise could have potential effects on both soil organic carbon (SOC) storage and the capability of certain management practices to sequester atmospheric carbon (C) in soils. In this study, we present the first regional estimation of SOC stock changes under climate change in Spanish agroecosystems. The Century model was applied over a 80-yr period (i.e., from 2007 to 2087) to an agricultural area of 40,498 km2 located in northeast Spain under five different climate scenarios. The model predicted an increase in SOC storage in the 0–30 cm soil depth in all the climate change scenarios tested (i.e., ECHAM4-A2, ECHAM4-B2, CGCM2-A2 and CGCM2-B2). Among climate change scenarios, SOC stock changes ranged from 0.15 to 0.32 Tg C yr−1. The Century model also predicted differences in SOC sequestration among agricultural classes. At the end of the simulation period, the greatest SOC stocks were found in the rainfed arable land under monoculture and no-tillage (MC-NT) class and in the grape-olive (GO) class with average stocks greater than 80 Mg C ha−1. On the contrary, both the alfalfa (AF) and the cereal-fallow (CF) classes showed the lowest SOC stocks with predicted values lower than 60 Mg C ha−1. Under climate change conditions, Spanish agricultural soils could act as potential atmospheric C sinks. Nevertheless, both the magnitude of the change in climate and the adoption of beneficial management practices could be critical in maximizing SOC sequestration.
Agricultural management plays an important role in global warming mitigation due to its effects on soil organic carbon (SOC) dynamics. In Mediterranean agroecosystems, the interactive effects of tillage and N fertilization on SOC storage have scarcely been studied. Hence, we here present a modelling study in which the effects of both tillage and N fertilization on SOC dynamics are investigated. We used SOC and C input data from a long-term (13 years) field study located in northeast Spain, firstly to validate both the Century model and the Rothamsted Carbon (RothC) model and secondly to predict future SOC dynamics until the year 2030. Tillage and N fertilization affected SOC stocks in the 0-30 cm soil layer. However, the interaction of the two factors was not significant. Averaged over the three N fertilization rates, the observed mean SOC stocks in conventional tillage (CT) and no-tillage (NT) were 29.8 and 36.8 Mg C ha(-1), respectively. In addition, the observed SOC stocks, averaged for both tillage systems, increased with increasing N rates, with 30.6, 33.5 and 35.8 Mg C ha(-1) for the 0,60 and 120 kg N ha(-1) rates, respectively. In general, both the Century model and the RothC model performed well in predicting SOC dynamics. Model predictions showed that in Mediterranean dryland agroecosystems SOC dynamics in the next 20 years would be variable according to the tillage and N fertilization applied. According to these predictions, scenarios with NT and high fertilization rates (e.g., 60-120 kg N ha(-1)) could lead to significant SOC sequestration and associated CO2 emission offsetting. However, these scenarios with high SOC sequestration rates also showed high mineral N accumulation in the soil profile with its associated environmental side effects. (C) 2012 Elsevier B.V. All rights reserved.
This Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) has been jointly coordinated by Working Groups I (WGI) and II (WGII) of the Intergovernmental Panel on Climate Change (IPCC). The report focuses on the relationship between climate change and extreme weather and climate events, the impacts of such events, and the strategies to manage the associated risks. This Special Report, in particular, contributes to frame the challenge of dealing with extreme weather and climate events as an issue in decision making under uncertainty, analyzing response in the context of risk management. The report consists of nine chapters, covering risk management; observed and projected changes in extreme weather and climate events; exposure and vulnerability to as well as losses resulting from such events; adaptation options from the local to the international scale; the role of sustainable development in modulating risks; and insights from specific case studies. (LN)
The most widely applied soil carbon models partition the soil organic carbon into two or more kinetically defined conceptual pools. The initial distribution of soil organic matter between these pools influences the simulations. Like many other soil organic carbon models, the DAYCENT model is initialised by assuming equilibrium at the beginning of the simulation. However, as we show here, the initial distribution of soil organic matter between the different pools has an appreciable influence on simulations, and the appropriate distribution is dependent on the climate and management at the site before the onset of a simulated experiment. If the soil is not in equilibrium, the only way to initialise the model is to simulate the pre-experimental period of the site. Most often, the site history, in terms of land use and land management is often poorly defined at site level, and entirely unknown at regional level. Our objective was to identify a method that can be applied to initialise a model when the soil is not in equilibrium and historic data are not available, and which quantifies the uncertainty associated with initial soil carbon distribution. We demonstrate a method that uses Bayesian calibration by means of the Accept–Reject algorithm, and use this method to calibrate the initial distribution of soil organic carbon pools against observed soil respiration measurements. It was shown that, even in short-term simulations, model initialisation can have a major influence on the simulated results. The Bayesian calibration method quantified and reduced the uncertainties in initial carbon distribution.
Summary The estimation of soil carbon content is of pressing concern for soil protection and in mitigation strategies for global warming. This paper describes the methodology developed and the results obtained in a study aimed at estimating organic carbon contents (%) in topsoils across Europe. The information presented in map form provides policy-makers with estimates of current topsoil organic carbon contents for developing strategies for soil protection at regional level. Such baseline data are also of importance in global change modelling and may be used to estimate regional differences in soil organic carbon (SOC) stocks and projected changes therein, as required for example under the Kyoto Protocol to the United Nations Framework Convention on Climate Change, after having taken into account regional differences in bulk density.The study uses a novel approach combining a rule-based system with detailed thematic spatial data layers to arrive at a much-improved result over either method, using advanced methods for spatial data processing. The rule-based system is provided by the pedo-transfer rules, which were developed for use with the European Soil Database. The strong effects of vegetation and land use on SOC have been taken into account in the calculations, and the influence of temperature on organic carbon contents has been considered in the form of a heuristic function. Processing of all thematic data was performed on harmonized spatial data layers in raster format with a 1 km × 1 km grid spacing. This resolution is regarded as appropriate for planning effective soil protection measures at the European level. The approach is thought to be transferable to other regions of the world that are facing similar questions, provided adequate data are available for these regions. However, there will always be an element of uncertainty in estimating or determining the spatial distribution of organic carbon contents of soils.
Relationships of soil water tension and hydraulic conductivity with soil water content are needed to quantify plant available water and to model the movement of water and solutes in and through soils. To provide the best estimates possible from previous analyses, a comprehensive search of the literature and data sources for hydraulic conductivity and related soil-water data was made in 1978. From this search, data for 1323 soils with about 5350 horizons from 32 states were assembled. -from Authors
Simulation modelling is used to estimate C sequestration associated with agricultural management for purposes of greenhouse gas mitigation. Models are not completely accurate or precise estimators of C pools, however, due to insufficient knowledge and imperfect conceptualizations about ecosystem processes, leading to uncertainty in the results. It can be difficult to quantify the uncertainty using traditional error propagation techniques, such as Monte Carlo Analyses, because of the structural complexity of simulation models. Empirically based methods provide an alternative to the error propagation techniques, and our objective was to apply this alternative approach. Specifically, we developed a linear mixed-effect model to quantify both bias and variance in modeled soil C stocks thatwere estimated using the Century ecosystem simulation model. The statistical analysis was based on measurements from 47 agricultural experiments. A significant relationship was found between model results and measurements although therewere biases and imprecision in the modeled estimates. Century under-estimated soil C stocks for several management practices, including organic amendments, no-till adoption, and inclusion of hay or pasture in rotation with annual crops. Century also over-estimated the impact ofNfertilization on soil C stocks. For lands set-aside fromagricultural production,
Century under-estimated soil C stocks on low carbon soils and over-estimated the stocks on high carbon soils. Using an empirically based approach allows for simulation model results to be adjusted for biases as well as quantify the variance associated with modeled estimates, according to the measured “reality” of management impacts from a network of experimental sites.
Crop residue incorporation is recognised as a simple way to increase C input into the soil, with positive effects on C sequestration from the atmosphere. However, in some long-term experiments, a lack of response to soil C input levels has been observed as a consequence of saturation phenomena and/or interactions between C input and fertilisation. This paper analyses the outcomes of a long-term experiment in north-eastern Italy that started in 1966 and is still ongoing, where residue incorporation is compared with residue removal, over a range of mineral N fertilisations. A general decrease of SOC content was observed in the first 10 years of the experiment, followed by an approach to a steady state. However, SOC content differed markedly according to residue management and, in plots with residue incorporation, to N fertilisation. Considering 20 years as a compromise period for reaching a new equilibrium after a land-use change, the sequestration rate of residue incorporation in comparison with removal resulted as 0.17 t ha- 1 of C per year. The measured data were then simulated with Century, a model based on first-order decomposition kinetic, to evaluate if the data could be interpreted by this kind of decomposition process. Model performances were good in most cases, but overestimated SOC decomposition in the more limiting situations for C and N inputs. A possible explanation is given for this behaviour, involving a feed-back effect of the microbial community.
Cited By (since 1996):15, Export Date: 3 June 2013, Source: Scopus
Soil contains approximately 2344 Gt (1 gigaton = 1 billion tonnes) of organic carbon globally and is the
largest terrestrial pool of organic carbon. Small changes in the soil organic carbon stock could result
in significant impacts on the atmospheric carbon concentration. The fluxes of soil organic carbon vary
in response to a host of potential environmental and anthropogenic driving factors. Scientists worldwide
are contemplating questions such as: ‘What is the average net change in soil organic carbon due
to environmental conditions or management practices?’, ‘How can soil organic carbon sequestration be
enhanced to achieve some mitigation of atmospheric carbon dioxide?’ and ‘Will this secure soil quality?’.
These questions are far reaching, because maintaining and improving the world’s soil resource is imperative
to providing sufficient food and fibre to a growing population. Additional challenges are expected
through climate change and its potential to increase food shortages. This review highlights knowledge
of the amount of carbon stored in soils globally, and the potential for carbon sequestration in soil. It also
discusses successful methods and models used to determine and estimate carbon pools and fluxes. This
knowledge and technology underpins decisions to protect the soil resource.
2006 IPCC Guidelines for preparation of National Greenhouse Gas Inventories -- guidelines for Iron and Steel and Metallurgical Coke Production (Contributing Author)
https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol3.html
IPCC Special Report on Emissions Scenarios Contents: Foreword Preface Summary for policymakers Technical Summary Chapter 1: Background and Overview Chapter 2: An Overview of the Scenario Literature Chapter 3: Scenario Driving Forces Chapter 4: An Overview of Scenarios Chapter 5: Emission Scenarios Chapter 6: Summary Discussions and Recommendations
Process-based ecosystem models are useful tools, not only for understanding the forest carbon cycle, but also for predicting future change. In order to apply a model to simulate a specific time period, model initialization is required. In this study, we propose a new scheme of initialization for forest ecosystem models, which we term a "slow-relaxation scheme", that entails scaling of the soil carbon and nitrogen pools slowly during the spin-up period. The proposed slow-relation scheme was tested with the CENTURY version 4 ecosystem model. Three different combinations of scaled soil pools were also tested, and compared to the results from a fast-relaxation regime. The fast-relaxation of soil pools produced unstable, transient model behaviour whereas slow-relaxation overcame this instability. This approach holds promise for initializing ecosystem models, and for starting simulations with more realistic initial conditions. © 2011 Elsevier B.V.
Summary Understanding the response of soil organic carbon (SOC) to environmental and management factors is necessary for estimating the potential of soils to sequester atmospheric carbon. Changes over time in the amount and distribution of SOC fractions with different turnover rates can be estimated by means of soil SOC models such as RothC, which typically consider two to five SOC pools. Ideally, these pools should correspond to measurable SOC fractions. The aim of this study was to test the relationship between SOC pools used in RothC and fractions separated through a fractionation procedure. A total of 123 topsoil samples from agricultural sites (arable land, grassland and alpine pasture) across Switzerland were used. A combination of physical and chemical methods resulted in two sensitive (particulate organic matter and dissolved organic carbon), two slow (carbon associated to clay and silt or stabilized in aggregates) and one passive (oxidation-resistant carbon) SOM fractions. These fractions were compared with the estimated equilibrium model pools when the corresponding soils were modelled with RothC. Analysis revealed strong correlations between SOC in measured fractions and modelled pools. Spearman's rank correlation coefficients varied between 0.82 for decomposable plant materials (DPM), 0.76 for resistant plant mate- rials (RPM), 0.99 for humified organic matter (HUM) and biomass (BIO), and 0.73 for inert organic matter (IOM). The results show that the proposed fractionation procedure can be used with minor adaptations to identify measurable SOC fractions, which can be used to initialize and evaluate RothC for a wide range of site conditions.
We present results from modelling studies, which suggest that, at most, only about 10–20% of recently observed soil carbon losses in England and Wales could possibly be attributable to climate warming. Further, we present reasons why the actual losses of SOC from organic soils in England and Wales might be lower than those reported.
Process-based model analyses are often used to estimate changes in soil organic carbon (SOC), particularly at regional to continental scales. However, uncertainties are rarely evaluated, and so it is difficult to determine how much confidence can be placed in the results. Our objective was to quantify uncertainties across multiple scales in a process-based model analysis, and provide 95% confidence intervals for the estimates. Specifically, we used the Century ecosystem model to estimate changes in SOC stocks for US croplands during the 1990s, addressing uncertainties in model inputs, structure and scaling of results from point locations to regions and the entire country. Overall, SOC stocks increased in US croplands by 14.6 Tg C yr−1 from 1990 to 1995 and 17.5 Tg C yr−1 during 1995 to 2000, and uncertainties were ±22% and ±16% for the two time periods, respectively. Uncertainties were inversely related to spatial scale, with median uncertainties at the regional scale estimated at ±118% and ±114% during the early and latter part of 1990s, and even higher at the site scale with estimates at ±739% and ±674% for the time periods, respectively. This relationship appeared to be driven by the amount of the SOC stock change; changes in stocks that exceeded 200 Gg C yr−1 represented a threshold where uncertainties were always lower than ±100%. Consequently, the amount of uncertainty in estimates derived from process-based models will partly depend on the level of SOC accumulation or loss. In general, the majority of uncertainty was associated with model structure in this application, and so attaining higher levels of precision in the estimates will largely depend on improving the model algorithms and parameterization, as well as increasing the number of measurement sites used to evaluate the structural uncertainty.
A model was developed to calculate carbon fluxes from agricultural soils. The model includes the effects of crop (species, yield and rotation), climate (temperature, rainfall and evapotranspiration) and soil (carbon content and water retention capacity) on the carbon budget of agricultural land. The changes in quality of crop residues and organic material as a result of changes in CO2 concentration and changed management were not considered in this model. The model was parameterized for several arable crops and grassland. Data from agricultural, meteorological, soil, and land use databases were input to the model, and the model was used to evaluate the effects of different carbon dioxide mitigation measures on soil organic carbon in agricultural areas in Europe. Average carbon fluxes under the business as usual scenario in the 2008–2012 commitment period were estimated at 0.52 tC ha−1 y−1 in grassland and −0.84 tC ha−1 y−1 in arable land. Conversion of arable land to grassland yielded a flux of 1.44 tC ha−1 y−1. Farm management related activities aiming at carbon sequestration ranged from 0.15 tC ha−1 y−1 for the incorporating of straw to 1.50 tC ha−1 y−1 for the application of farmyard manure. Reduced tillage yields a positive flux of 0.25 tC ha−1 y−1. The indirect effect associated with climate was an order of magnitude lower. A temperature rise of 1 °C resulted in a −0.05 tC ha−1 y−1 change whereas the rising CO2 concentrations gave a 0.01 tC ha−1 y−1 change. Estimates are rendered on a 0.5 × 0.5° grid for the commitment period 2008–2012. The study reveals considerable regional differences in the effectiveness of carbon dioxide abatement measures, resulting from the interaction between crop, soil and climate. Besides, there are substantial differences between the spatial patterns of carbon fluxes that result from different measures.
We present the most comprehensive pan-European assessment of future changes in cropland and grassland soil organic carbon (SOC) stocks to date, using a dedicated process-based SOC model and state-of-the-art databases of soil, climate change, land-use change and technology change. Soil carbon change was calculated using the Rothamsted carbon model on a European 10 × 10′ grid using climate data from four global climate models implementing four Intergovernmental Panel on Climate Change (IPCC) emissions scenarios (SRES). Changes in net primary production (NPP) were calculated by the Lund–Potsdam–Jena model. Land-use change scenarios, interpreted from the narratives of the IPCC SRES story lines, were used to project changes in cropland and grassland areas. Projections for 1990–2080 are presented for mineral soil only.