Article

The potential for Scottish cultivated topsoils to lose or gain soil organic carbon

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Abstract

Scotland's cultivated topsoils are rich in carbon with a median soil organic carbon (SOC) content of ca. 3.65%. The storage of carbon in soil is a means to offset GHG emissions, but equally carbon losses from soils can add to these emissions. We estimate the amount of carbon stored in Scottish cultivated mineral topsoils (246 ± 9 Mt), the potential carbon loss (112 ± 12 Mt) and the carbon storage potential of between 150 and 215 Mt based on national-scale legacy data with uncertainty around the estimate due to error terms in predicting bulk densities for stock calculations. We calculate that Scotland's mineral cultivated topsoils hold the carbon equivalent of around 18 years of GHG emissions (based on 2009 emissions from all sources). We also derive a theoretical carbon saturation potential using a published, linear relationship with the

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... 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). ...
... The proposed data-driven approach integrating with the anthropogenic activities and different expectation objectives for estimating SOC storage potential made several improvements compared to the previous data-driven approaches Lilly and Baggaley, 2013). Firstly, the expectation percentiles were adopted instead of only maximum observed SOC values (Lilly and Baggaley, 2013;Stolbovoy Fig. 6. ...
... The proposed data-driven approach integrating with the anthropogenic activities and different expectation objectives for estimating SOC storage potential made several improvements compared to the previous data-driven approaches Lilly and Baggaley, 2013). Firstly, the expectation percentiles were adopted instead of only maximum observed SOC values (Lilly and Baggaley, 2013;Stolbovoy Fig. 6. Variable importance measures in relation to CLS revalent SOC storage potential. ...
Article
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.
... t ha -1 carbon in the top 1m. Scaled to the overall area of arable and improved grasslands in Scotland, this equates to around 102 (±14) and 152 (±24) Mt carbon and is not dissimilar to that calculated by Lilly and Baggaley (2013). ...
... Estimates of potential cultivated topsoil carbon loss and gain are based on existing data captured over several years or even decades (Lilly & Baggaley, 2013). Without ongoing detailed monitoring of soil carbon stocks and changes across Scotland, there is a limit to what can be extracted from existing datasets. ...
... The amount that could be potentially lost (Potential Carbon loss, PCL) was the difference between the average and the observed minimum (Figure 3). The original work by Lilly and Baggaley (2013) just considered cultivated topsoils and treated topsoils under improved grassland, rotational grass and arable as one dataset. For this report, this approach has been modified to separate grassland from arable topsoils as soils under arable agriculture potentially have a greater range of management options to increase carbon storage. ...
Technical Report
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Soils are one of the world's biggest stores of carbon. The level of carbon storage depends on several factors, including the type of organic matter, climatic conditions and land management practices, both past and present. Scottish Government asked ClimateXChange to explore how the level of storage over time could be measured, and how this could help improve land management practices through a payment system.
... Work by Hassink (1997) suggested that the amount of carbon that can be sequestered over the long term (as opposed to stored in the short term) in mineral soils was dependant on the proportion of clay and silt sized particles. Based on the same data used by Lilly and Baggaley (2013), this theoretical minimum carbon stock that is sequestered in cultivated mineral topsoils in Scotland was estimated to be 116 ± 14 Mt suggesting that the potential loss could be as great as 131 (109 -153) Mt. However, there is uncertainty regarding the role of soil texture as opposed to other soil and environmental conditions remains uncertain and is the topic of ongoing research. ...
... Chamberlain et al (2010) showed mean topsoil carbon stocks were measured at 619, 623 and 628 Mt carbon in 1978, 1998 and 2007 respectively, using Countryside Survey of Scotland, England and Wales data showing no significant difference over this period. Lilly and Baggaley (2013) estimate the amount of carbon stored in Scottish cultivated mineral soils is 246±9 Mt, but that there is a potential to increase this by between 150 and 215 Mt based on national scale legacy data with uncertainty around the estimate due to error terms predicting bulk densities for stock calculations. The State of Scottish Soils Report highlights the potential for carbon sequestration in arable farming focused in south and east Scotland, which has lower organic matter (OM) resulting in much interest in managing soils to increase carbon in these areas. ...
... A recent Defra report indicated that since arable soils tend to have smaller soil carbon contents than grassland soils they will have greater potential for increased soil carbon storage. Evidence to support this is provided by Lilly and Baggaley (2013). There are few data available to quantify the effect of rotation on soil carbon increases in tilled soils in NW Europe and no specific reviews or meta-analyses were found . ...
Technical Report
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Soil carbon has been identified as a priority issue by the Scottish Government in climate change policy across several areas. There is particular interest in the potential of soils to provide carbon sequestration as a contribution to the annual emissions reductions targets, with links to agriculture, renewable energy and other primary land uses. This project synthesises the current state of knowledge on soil carbon and land use in Scotland. 1. Key findings  There is strong scientific evidence of consensus in several key areas including the importance of Scottish soils for the storage of carbon, and the amounts of carbon stored in different soil types across the country  There was an absence of evidence around potentially key issues including the amount of carbon that can be sequestered by restoration of organic soils, rotational grass, the future carbon sequestration potentials of long term grasslands and arable soils  The evidence base is consistent on the overall levels of soil carbon in Scotland (around 3000 Mt), and on the amount (1600 Mt) stored in peats and peaty soils.  The available evidence suggests that there have been no significant changes in the storage of carbon taking place in arable or grassland soils since 1978. However, it can be demonstrated that older grasslands (greater than 5 years) will store more carbon  The uptake of atmospheric carbon dioxide (CO2) by land use and land use change (10 Mt CO2e/year) is of a similar magnitude to the total greenhouse gas emissions from agriculture in Scotland  There is broad agreement across the evidence studied that some opportunities exist to use agricultural management to increase carbon storage in agricultural soils (estimated to be 174 Mt C), although there are possibly greater opportunities to reduce non CO2 greenhouse gas emissions from agriculture (currently 7.4 Mt CO2e/year)  Emissions of gases other than CO2 (methane and nitrous oxide) dominate agriculture’s contribution to greenhouse gas emissions. An improved understanding to these emissions is likely to lead to greater opportunities for mitigation than that provided by increasing carbon sequestration  The evidence base is consistent in the conclusion that peatland restoration offers significant opportunities to increase carbon storage in Scottish soils but there are large uncertainties (ranging between a net uptake of 8.1 Mt CO2e/year to net loss of 2.8 Mt CO2e/year )  There are considerable uncertainties in predicting the future effects of land use change, climate, and management and their interactions on future carbon stocks. This is due to uncertainties in future global atmospheric greenhouse gas concentrations, and the consequent response of soils to altered climatic conditions  The UK and Scottish inventories of greenhouse gas emissions and removals do not currently report changes in soil carbon stocks in areas of grassland and cropland that remain in the same land use. As new evidence emerges of such changes it is likely in future that new reporting procedures will be adopted that reflect such changes  Work is ongoing in trying to establish better emission factors for the UK peatlands. It is expected that the findings of a DECC-funded project, which will collate both the historic and the most recent UK-relevant data, will be published in the near future.
... This would also ensure that UK agriculture could demonstrate no leakage or reversals from either soil carbon stocks or soil GHGs in a fully accountable contribution to climate change mitigation through carbon-positive soil management. There is considerable scope to reduce direct soil GHGs from UK agriculture since agricultural soils account for 68% of UK's total N 2 O emissions Office for National Statisti (ONS) [36] while arable mineral soils are relatively low in soil organic carbon [37] with substantial potential for sequestration [38]. However, the rationale for a combined scope should not be based solely on this potential. ...
Article
Full-text available
Soils have the potential to sequester and store significant amounts of carbon, contributing towards climate change mitigation. Soil carbon markets are emerging to pay farmers for management changes that absorb atmospheric carbon, governed by codes that ensure eligibility, additionality and permanence whilst protecting against leakage and reversals. This paper presents the first global comparative analysis of farmland soil carbon codes, providing new insights into the range of approaches governing this global marketplace. To do this, the paper developed an analytical framework for the systematic comparison of codes which was used to identify commonalities and differences in approaches, methods, administration, commercialisation and operations for 12 publicly available codes from around the world. Codes used a range of mechanisms to manage additionality, uncertainty and risks, baselines, measurement, reporting and verification, auditing, resale of carbon units, bundling and stacking, stakeholder engagement and market integrity. The paper concludes by discussing existing approaches and codes that could be adapted for use in the UK and evaluates the need for an over-arching standard for soil carbon codes in the UK and internationally, to which existing codes and other schemes already generating soil carbon credits could be assessed and benchmarked.
... This would also ensure that UK agriculture could demonstrate no leakage or reversals from either soil carbon stocks or GHGs in a fully accountable contribution to climate change mitigation through carbon-positive soil management. There is considerable scope to reduce direct soil GHGs from UK agriculture since agricultural soils account for 68% of UK's total N2O emissions (ONS, 2021) while arable mineral soils are relatively low in soil organic carbon (Reynolds et al 2914) with substantial potential for sequestration (e.g., Lilly & Baggaley, 2013). However, the rationale for a combined scope should not solely be based on this potential. ...
Preprint
Full-text available
Soils have the potential to sequester and store significant amounts of carbon, contributing towards climate change mitigation. Soil carbon markets are now emerging to pay farmers for changes in land use or management that absorb carbon from the atmosphere, governed by codes that ensure additionality, permanence and non-leakage whilst protecting against unintentional reversals. This paper represents the first global comparative analysis of agricultural soil carbon codes, providing new insights into the wide range of approaches currently used to govern these emerging markets internationally. To do this, the paper first develops an analytical framework for the systematic comparison of codes, which could be applied to the analysis of codes in other land uses and habitats. This framework was then used to identify commonalities and differences in methods, projects, administration and commercialisation and associated code documents for 12 publicly available codes from the UK, France, Australia, USA and international bodies. Codes used a range of mechanisms to manage: additionality (including legal, adoption, financial viability and investment tests); uncertainty and risks around soil carbon sequestration (including minimum permanence periods, carbon buffers, contractual arrangements and/or insurance policies); leakage (including restriction of eligible practices and monitoring to subtract leakage from verified sequestration); baselines (including multi-year and variable buffers based on empirical data or models); measurement, reporting and verification methods (stipulating time intervals, methods, data sources and assessments of uncertainty); auditing; resale of carbon units; stakeholder engagement; and approaches to ensure market integrity (such as buyer checks). The paper concludes by discussing existing MRV methods and codes that could be adapted for use in the UK and evaluates the need for an over-arching standard for soil carbon codes in the UK, to which existing codes and other schemes already generating soil carbon credits could be assessed and benchmarked.
... There are significant stores of organic matter in Scotland's grassland soils (Aitkenhead and Coull 2016) and soils under arable cropping could potentially store significant amounts of carbon (Lilly and Baggaley 2013). However, the technological development of solutions to manage and monitor soil is only part of the solution. ...
Preprint
The Scottish Government has recognised that soils perform many vital functions for the health of the environment and economy. In the last decade, there has been significant research output from several organisations across Scotland, in collaboration with partners in the rest of the UK and further afield. In this review, I highlight recent research focused on soil organic matter in the context of the main external drivers (land management and climate change). This review demonstrates the strengths and successes of the relatively tightly integrated policy-research-regulatory landscape in Scotland. It also highlights the need for more and greater impact through interdisciplinary and transdisciplinary research involving soil scientists, social scientists, policymakers and land managers. Evidence is presented that meaningful (rather than incremental) changes to climate change mitigation and adaptation policies and practices are necessary, with a further need for researchers and policymakers to consider both local conditions and global impacts of future climate on the practical implementation of soil-based climate change mitigation and adaptation strategies in Scotland. The role of environmental and social scientists through advocacy as well as research is explored and discussed.
... Stolbovoy and Montanarella (2008) used data from the European Soil Portal database to determine the maximum observed SOC stocks for a given soil type under a given climate, from which they subtracted the observed SOC stocks under cultivated land. Lilly and Baggaley (2013) determined for each typological soil unit the observed maximum SOC stocks, from which they subtracted the observed median SOC stock under cultivated topsoils. One main difference between these studies and the present one is that they did not calculate percentiles but used only as reference the maximum observed values which are obviously much more sensitive to the presence of very high values. ...
Thesis
This thesis is a contribution to Digital Soil Mapping (DSM) at broad scale, with applications on the French mainland territory. In Chapter 1, I discussed the main drivers for the rise and development of DSM and gave a brief history about DSM. In Chapter 2, I made a general review about broad-scale DSM by reviewing 160 selected articles from 2003 to mid-2019. I synthetized and discussed the main achievements and challenges for the DSM community. Then I decided to focus on soil organic carbon (SOC) because of its main importance for ecosystem services and global carbon cycle. In Chapter 3, I showed how to improve a national SOC map by merging various SOC maps and provided inputs on how to take advantage of global predictions in ‘data-poor’ countries using a low cost and efficient sampling strategy. Then in Chapters 4 and 5, I focused onthe validity domain of pedotransfer functions used for bulk density predictions and on developing a novel approach to deal with soil thickness prediction over France. I also proposed efficient sampling strategies to improve the accuracy of their predictions. I moved from DSM to Digital Soil Assessment (DSA), exemplified by SOC sequestration potential in Chapter 6 and SOC storage potentials in Chapter 7. They contribute to improving some aspects related to DSM and GlobalSoilMap. In Chapter 8, I finished this thesis by discussing the most important findings of my work and relating them to main challenges of Pedometrics. I outlined the inputs that my work provided to reaching these challenges and highlighted the remaining issues to be solved in
... However, several studies use the original equation presented by Hassink, (1997) to estimate sequestration potential at different scales (e.g. Angers et al., 2011;Chen et al., 2019;Lilly and Baggaley, 2013;Wiesmeier et al., 2014). This is frequently done without any validation 70 checks to determine the suitability of the Hassink, (1997) linear regression equation to predict MAOCmax in the respective studies. ...
Preprint
Full-text available
Soil organic carbon (SOC) sequestration across agroecosystems worldwide can contribute to mitigate the effects of climate change by reducing levels of atmospheric CO2. Mineral associated organic carbon (MAOC) is considered an important long-term store of SOC and the saturation deficit (difference between measured MAOC and estimated maximum MAOC) is frequently used to assess SOC sequestration potential following the linear regression equation developed by Hassink (1997). However, this approach is often taken without any assessment of the fit of the equation to the soils being studied. The statistical limitations of linear regression have previously been noted, giving rise to the proposed use of boundary line (BL) analysis and quantile regression (QR) to provide more robust estimates of maximum SOC stabilisation. The objectives of this work were to assess the suitability of the Hassink (1997) equation to estimate maximum MAOC in UK grassland soils of varying sward ages and to evaluate the linear regression, BL and QR methods to estimate maximum MAOC. A chronosequence of 10 grasslands was sampled, in order to assess the relationship between sward age (time since last reseeding event) and current and predicted maximum MAOC. Significantly different regression equations show that the Hassink (1997) equation does not accurately reflect maximum MAOC in UK grasslands when determined using the proportion of fine soil fraction and current MAOC. The QR estimate of maximum SOC stabilisation was almost double that of linear regression and BL analysis (0.89 ± 0.074, 0.43 ± 0.017 and 0.57 ± 0.052 g C kg−1 soil, respectively). Sward age had an inconsistent effect on the measured variables and potential maximum MAOC. MAOC across the grasslands made up 4.5 to 55.9 % of total SOC, implying that there may be either high potential for additional C sequestration in the mineral fraction of these soils, or stabilisation in aggregates is predominant in these grassland soils. This work highlights the need to ensure that methods used to predict maximum MAOC reflect the soil in situ, resulting in more accurate assessments of carbon sequestration potential.
... However, changes in some soil properties have been recorded across GB during this time (e.g. Chapman et al, 2015, Lilly and Baggaley, 2013, Bellamy et al, 2005, Reynolds et al, 2013 reflecting pollution recovery, climate change and land management changes (Kirk et al, 2010;Bell et al, 2011). These changes would be reflected in these independent datasets and as a result would influence the evaluation of the outcome of the training and validation. ...
... Stolbovoy and Montanarella (2008) calculated the carbon storage potential for cultivated soils in EU by subtracting the average present SOC stock, for each soil typological unit, from the maximum SOC content observed for that soil typological unit, both numbers being obtained from the 1:1,000,000 European soil spatial data set. Lilly and Baggaley (2013) applied this method to Scotland, i.e. at a finer resolution. The same approach could be developed at the scale of small regions, provided a soil map is available as well as sufficient data on SOC stocks. ...
Article
Recent initiatives, such as the United Nations declaring 2015 as the International Year of Soils and the French « 4 per 1000 » initiative call attention on soils and on the importance of maintaining and increasing soil organic matter stocks for soil fertility and food security, and for climate change adaptation and mitigation. We stress that soil organic carbon storage (i.e. an increase of soil organic carbon stocks) should be clearly differentiated from soil organic carbon sequestration, as the latter assumes a net removal of atmospheric CO2. Implementing management options that allow increasing soil organic carbon stocks at the local scale raises several questions, which are discussed in this article: how can we increase SOC stocks, at which rate and for how long; where do we prioritize SOC storage; how do we estimate the potential gain in C and which agricultural practices should we implement? We show that knowledge and tools are available to answer many of these questions, while further research remains necessary for others. A range of agricultural practices would require a re-assessment of their potential to store C and a better understanding of the underlying processes, such as no tillage and conservation agriculture, irrigation, practices increasing below ground inputs, organic amendments, and N fertilization. The vision emerging from the literature, showing the prominent role of soil microorganisms in the stabilization of soil organic matter, draw the attention to more exploratory potential levers, through changes in microbial physiology or soil biodiversity induced by agricultural practices, that require in-depth research.
... Stolbovoy and Montanarella (2008) used data from the European Soil Portal database to determine the maximum observed SOC stocks for a given soil type under a given climate, from which they subtracted the observed SOC stocks under cultivated land. Lilly and Baggaley (2013) determined for each typological soil unit the observed maximum SOC stocks, from which they subtracted the observed median SOC stock under cultivated topsoils. One main difference between these studies and the present one is that they did not calculate percentiles but used only as reference the maximum observed values which are obviously much more sensitive to the presence of very high values. ...
Article
Soil organic carbon (SOC) is important for its contributions to agricultural production, food security, and ecosystem services. Increasing SOC stocks can contribute to mitigate climate change by transferring atmospheric CO2 into long-lived soil carbon pools. The launch of the 4 per 1000 initiative has resulted in an increased interest in developing methods to quantity the additional SOC that can be stored in soil under different management options. In this work, we have made a first attempt to estimate SOC storage potential of arable soils using a data-driven approach based on the French National Soil Monitoring Network. The data-driven approach was used to determine the maximum SOC stocks of arable soils for France. We first defined different carbon-landscape zones (CLZs) using clustering analysis. We then computed estimates of the highest possible values using percentile of 0.8, 0.85, 0.9 and 0.95 of the measured SOC stocks within these CLZs. The SOC storage potential was calculated as the difference between the maximum SOC stocks and current SOC stocks for topsoil and subsoil. The percentile used to determine highest possible SOC had a large influence on the estimates of French national SOC storage potential. When the percentile increased from 0.8 to 0.95, the national SOC storage potential increased by two to three-fold, from 336 to 1020 Mt for topsoil and from 165 to 433 Mt for subsoil, suggesting a high sensitivity of this approach to the selected percentile. Nevertheless, we argue that this approach can offer advantages from an operational point of view, as it enables to set targets of SOC storage taking into account both policy makers' and farmers' considerations about their feasibility. Robustness of the estimates should be further assessed using complementary approaches such as mechanistic modelling.
... Blake & Mattisson Potential integration with other spatial datasets available for Scotland including: suitability mapping for native woodland creation, carbon stock mapping, changes to distribution of ‗prime' land under climate change and Ecosystem Service Mapping. Lilly & Baggaley 2013, Towers et al. 2011, Brown et al. 2008, Winn et al. 2015a ...
... Their condition, therefore, will be a key for their ability to increase total carbon stocks in Scotland. Different estimates of Scottish soil carbon stocks exist based on different methods, e.g. a traditional approach (Chapman et al., 2013, Lilly andBaggaley, 2013), a machine learning (Aitkenhead and Coull, 2016) and a hybrid generalised additive model (GAM) geostatistical 3D model (Poggio and Gimona, 2014). While considering the geostatistical approach (Fig. 12) the average stock is 429 t C ha −1 (3.14 Gt) of which 300 t C ha − 1 (0.704 Gt) in mineral soils, 461 t C ha −1 (1.57 ...
Article
Full-text available
The '4 per mille Soils for Food Security and Climate' was launched at the COP21 with an aspiration to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year as a compensation for the global emissions of greenhouse gases by anthropogenic sources. This paper surveyed the soil organic carbon (SOC) stock estimates and sequestration potentials from 20 regions in the world (New and Russia). We asked whether the 4 per mille initiative is feasible for the region. The outcomes highlight region specific efforts and scopes for soil carbon sequestration. Reported soil C sequestration rates globally show that under best management practices, 4 per mille or even higher sequestration rates can be accomplished. High C sequestration rates (up to 10 per mille) can be achieved for soils with low initial SOC stock (topsoil less than 30 t C ha −1), and at the first twenty years after implementation of best management practices. In addition, areas which have reached equilibrium will not be able to further increase their sequestration. We found that most studies on SOC sequestration only consider topsoil (up to 0.3 m depth), as it is considered to be most affected by management techniques. The 4 per mille number was based on a blanket calculation of the whole global soil profile C stock, however the potential to increase SOC is mostly on managed agricultural lands. If we consider 4 per mille in the top 1m of global agricultural soils, SOC sequestration is between 2-3 Gt C year −1 , which effectively offset 20–35% of global anthropogenic greenhouse gas emissions. As a strategy for climate change mitigation, soil carbon sequestration buys time over the next ten to twenty years while other effective sequestration and low carbon technologies become viable. The challenge for cropping Geoderma j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / g e o d e r m a farmers is to find disruptive technologies that will further improve soil condition and deliver increased soil carbon. Progress in 4 per mille requires collaboration and communication between scientists, farmers, policy makers, and marketeers.
... In this study we use non-informative priors for all coefficients excluding the distribution of the variable of interest which were based on information derived from past experience Poggio et al., 2013) and existing literature (Chapman et al., 2013;Lilly and Baggaley, 2013) for each of the three soil groupings (see Table 1). The values were obtained by reclassification of soils and land use and by transformation from soil organic carbon to soil organic matter, where necessary. ...
... This approach has been used in the USA to produce maps of carbon concentration for the global soil map (Odgers et al. 2012). Carbon concentrations and predicted bulk densities have been combined to predict carbon stocks and potential carbon storage in soils using 1:1,000,000 soil typological units for Europe (Stolbovoy and Montanarella 2008) and 1:250,000 scale map unit data in Scotland (Lilly and Baggaley 2013). ...
Chapter
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The Scottish Government wish to preserve the carbon stocks already stored or sequestered in both organic and mineral soils and see land-use change as one of the key drivers affecting storage of soil organic carbon (SOC). A key component to develop any strategy to maintain the existing carbon stocks is the quantification of these stocks both in terms of the carbon content and its spatial distribution. To date, two different methods that use the same existing legacy data have been used to quantify carbon stocks in Scotland: a traditional approach and a hybrid generalised additive model (GAM)—geostatistical 3D model. Each of the methods revealed differences in the spatial patterns of SOC stocks. Understanding these differences will enable the development of more robust and accurate models that can be used to assess changes in stocks due to changing land use. Here, we compare these methods for the Scottish mainland, Western Isles, and Orkney. The traditional approach was based on calculating average organic carbon values from a subset (6000) of around 40,000 observations stored within the Scottish Soil Database. The total SOC stock was then determined by multiplying the areal extent of each soil series/land-use combination by the calculated profile stock. The uncertainty was also quantified based on standard error of the measured carbon contents and the uncertainty in the bulk density pedotransfer functions. A hybrid GAM-geostatistical 3D model combined the fitting of a GAM using a 3D smoother with related covariates and the kriging or Gaussian simulations of the residuals to spatially account for local details. The uncertainty was also calculated and was found to be large, indicating a wide range of credible values for each pixel. The deviation from the median ranges was between 5 and 75 % for the interpolated values depending on location.
... The credible range is likely to be underestimated as the variance of the predicted results is reduced due to the use of logtransformation on the data in particular with a compression of the tails of the distribution. The large uncertainty is consistent with the large ranges found for SOC summary values per soil mapping unit reported in Lilly and Baggaley (2013). Large values of variability are also obtained when considering the deviation of the realisations from the median. ...
Article
Abstract The variation of soil properties down a profile is usually considered continuous. The aim of this study was to develop and test a methodology to model the continuous vertical and lateral distributions of SOC stocks in Scottish soils making explicit the modelling and spatial uncertainty of the results. A comparison with regression kriging and other depth function methods is provided to show that better performances can be achieved taking into account non-linear relationships between covariates and soil properties. The analysis was run for the whole of Scotland. The carbon stocks were calculated for each point, i.e. each horizon in each available profile. The stock value at each cell for each of the considered depth layers was defined using a hybrid GAM-geostatistical 3D model, combining: 1) the fitting of a GAM to estimate the trend of the variable, using a 3D smoother with related covariates; and 2) kriging or Gaussian simulations of GAM residuals as spatial component to account for local details. The use of GAM makes the approach flexible, because it is able to deal with both linear and non-linear relationships between soil properties and the considered covariates. The results confirmed that MODIS data are a useful source of information for DSM especially at national scale. When comparing the proposed approach with similar methods such as regression kriging, the results showed better agreement with the data in the validation set with a global R2 of 0.60. The median values obtained are comparable with the values reported from previous studies on stocks in Scotland using different methods. The uncertainty is large indicating a wide range of credible values for each pixel.
Article
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A framework for estimating the distribution of soil Ecosystem Service (ES) supply is described that is based on the concept of matrix multiplication. This approach enables relationships between fundamental soil variables and associated environmental characteristics to be linked to soil processes, and hence to ecosystem functions and ecosystem services. The parameterisation of these relationships was achieved using a combination of data from the Scottish Soils Database and expert knowledge. Baseline data to allow mapping of processes, functions and services across Scotland is given by digital maps of soil classes. The matrix multiplication approach constrains the relationship linkages to linear relationships and ignores potential synergies between factors at each stage, but does provide a mechanism for relating fundamental soil characteristics to ecosystem services. The approach has been tested by developing maps of selected ecosystem services in Scotland and comparing these with existing maps of the same or similar ESs. While the values and their ranges differs in each case, the spatial distribution of services is similar. The proposed mechanism is extensible at every level and can also be used to explore the impacts of land management options on environmental characteristics. This is demonstrated by using the model to estimate impacts of liming on three ecosystem services: Agricultural Capability, Carbon Sequestration and Drinking Water Provision. The model is shown to produce reasonable estimation of the impacts of this management option. Further discussion of improvements to the system and its potential applications is given. This article is protected by copyright. All rights reserved.
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An increase in soil organic carbon stock can contribute to mitigate climate change. International negotiation mechanisms and initiatives call for countries to consider land use change and soil management to achieve atmospheric CO2 removal through storage in terrestrial systems (http://4p1000.org/). As a result, policy makers raised a specific operational question to the soil science community: how much and at which annual rate additional carbon can be stored in soils in different locations? It has been suggested that the ability of a soil to store additional organic carbon can be estimated from its carbon saturation deficit (Csat-def), which is defined as the difference between the maximum amount of carbon that can be associated to its fine (sat-def is not appropriate, at least in its present form, for assessing quantitatively the whole-soil (total) organic carbon storage potential for operational purposes. We then propose alternative approaches based on new opportunities offered by the development of national and international soil monitoring programs (possibly coupled with modelling) that can provide quantitatively relevant estimates of soil total carbon storage potential. This pragmatic approach will require a sustained effort to maintain and develop soil monitoring programs worldwide and research allowing proper use of such a large amount of data.
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Legacy data collected over 70 years are being used to address policy questions posed by the Scottish Government and to develop new ways of quantifying the distribution of soil carbon in Scotland. Traditional map-based methods, neural networks and spectral analyses are used to assess changes in carbon stocks over time and sequestration potential. Scottish peat soils are estimated to contain 1620 70 Mt carbon and cultivated mineral topsoils 246 9 Mt. These stocks are vulnerable to loss but a study to assess change showed no detectable losses under all land uses apart from woodland where gains were recorded. Smart phone apps have been developed that allow the carbon content of soils to be estimated based on a georeferenced photograph and an underlying neural network which makes use of legacy data. Legacy data have also been used to estimate carbon contents at 100 m resolution throughout Scotland.
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In order to predict the response of carbon (C)-rich soils to external change, models are needed that accurately reflect the conditions of these soils. Here we present an example application of the new Estimation of Carbon in Organic Soils - Sequestration and Emissions (ECOSSE) model to estimate net change in soil C in response to changes in land use in Scotland. The ECOSSE estimate of annual change in soil C stocks for Scotland between 2000 and 2009 is -810 +/- 89 kt yr(-1), equivalent to 0.037 +/- 0.004% yr(-1). Increasing the area of land-use change from arable to grass has the greatest potential to sequester soil C, and reducing the area of change from grass to arable has the greatest potential to reduce losses of soil C. Across Scotland, simulated changes in soil C from C-rich soils (C content >6%) between 1950 and 2009 is -63 Mt, compared with -35 Mt from non-C-rich mineral soils; losses from C-rich soils between 2000 and 2009 make up 64% of the total soil C losses. One mitigation option that could be used in upland soils to achieve zero net loss of C from Scottish soils is to stop conversion of semi-natural land to grassland and increase conversion of grassland to semi-natural land by 125% relative to the present rate. Mitigation options involving forestry are not included here because the data available to calculate losses of soil C do not account for losses of soil C on drainage of semi-natural land.
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Soil texture can be an important control on soil organic carbon (SOC) retention and dynamics. The (clay + silt)-sized SOC pool (SOC < 20 μm) in non-cultivated or grassland soils has been proposed to reach an equilibrium or maximum level named protective capacity. Proper knowledge of SOC in this size fraction in non-cultivated and cultivated Black soils is important to evaluate management-induced changes in SOC in NE China. Twenty-seven paired soil samples (non-cultivated vs. cultivated) were collected in the Black soil zone in Heilongjiang and Jilin provinces. Bulk soil was dispersed in water with an ultrasonic probe and then soil size fractions were collected using the pipette technique for SOC analyses. Soil organic carbon in bulk soil and size fractions was measured by dry combustion. Average content of SOC < 20 μm was 23.2 g C kg-1 at the 0-30 cm depth for the non-cultivated soils, accounting for 75.1% of the total SOC at the same depth. There was significant positive relationship between soil clay plus silt content and SOC < 20 μm in non-cultivated soils. Accordingly, a model of the maximum SOC < 20 μm in 0-30 cm depth of non-cultivated Black soils was developed: y = 0.36x where y is the maximum SOC < 20 μm pool (g C kg-1) and x is the percentage of clay + silt (<20 μm) content. The average content of SOC < 20 μm was 18.7 g C kg-1 at 0-30 cm depth for cultivated soils, accounting for 81.5% of total SOC. This average value of SOC was 4.4 g C kg-1 less than the maximum value (23.1 g C kg-1) and accounted for 55.0% of the difference of SOC between non-cultivated and cultivated Black soils. Cultivation resulted in 45.0% loss of sand-sized (>20 μm) SOC concentration relative to SOC < 20 μm. This result indicates that SOC < 20 μm and sand-sized SOC both play important roles in SOC dynamics resulting from management practices. This model can be applied to calculate the actual potential to restore SOC for cultivated Black soils under conservation tillage in NE China.
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Although it has been recognized that the adsorption of organics to clay and silt particles is an important determinant of the stability of organic matter in soils, no attempts have been made to quantify the amounts of C and N that can be preserved in this way in different soils. Our hypothesis is that the amounts of C and N that can be associated with clay and silt particles is limited. This study quantifies the relationships between soil texture and the maximum amounts of C and N that can be preserved in the soil by their association with clay and silt particles. To estimate the maximum amounts of C and N that can be associated with clay and silt particles we compared the amounts of clay- and silt-associated C and N in Dutch grassland soils with corresponding Dutch arable soils. Secondly, we compared the amounts of clay- and silt-associated C and N in the Dutch soils with clay and silt-associated C and N in uncultivated soils of temperate and tropical regions. We observed that although the Dutch arable soils contained less C and N than the corresponding grassland soils, the amounts of C and N associated with clay and silt particles was the same indicating that the amounts of C and N that can become associated with this fraction had reached a maximum. We also observed close positive relationships between the proportion of primary particles < 20 μm in a soil and the amounts of C and N that were associated with this fraction in the top 10 cm of soils from both temperate and tropical regions. The observed relationships were assumed to estimate the capacity of a soil to preserve C and N by their association with clay and silt particles. The observed relationships did not seem to be affected by the dominant type of clay mineral. The only exception were Australian soils, which had on average more than two times lower amounts of C and N associated with clay and silt particles than other soils. This was probably due to the combination of low precipitation and high temperature leading to low inputs of organic C and N. The amount of C and N in the fraction > 20 μm was not correlated with soil texture. Cultivation decreased the amount of C and N in the fraction > 20 μm to a greater extent than in the fraction < 20 μm, indicating that C and N associated with the fraction < 20 μm is better protected against decomposition. The finding of a given soil having a maximum capacity to preserve organic C and N will improve our estimations of the amounts of C and N that can become stabilized in soils. It has important consequences for the contribution of different soils to serve as a sink or source for C and N in the long term.
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The relationship between soil structure and the ability of soil to stabilize soil organic matter (SOM) is a key element in soil C dynamics that has either been overlooked or treated in a cursory fashion when developing SOM models. The purpose of this paper is to review current knowledge of SOM dynamics within the framework of a newly proposed soil C saturation concept. Initially, we distinguish SOM that is protected against decomposition by various mechanisms from that which is not protected from decomposition. Methods of quantification and characteristics of three SOM pools defined as protected are discussed. Soil organic matter can be: (1) physically stabilized, or protected from decomposition, through microaggregation, or (2) intimate association with silt and clay particles, and (3) can be biochemically stabilized through the formation of recalcitrant SOM compounds. In addition to behavior of each SOM pool, we discuss implications of changes in land management on processes by which SOM compounds undergo protection and release. The characteristics and responses to changes in land use or land management are described for the light fraction (LF) and particulate organic matter (POM). We defined the LF and POM not occluded within microaggregates (53–250 m sized aggregates as unprotected. Our conclusions are illustrated in a new conceptual SOM model that differs from most SOM models in that the model state variables are measurable SOM pools. We suggest that physicochemical characteristics inherent to soils define the maximum protective capacity of these pools, which limits increases in SOM (i.e. C sequestration) with increased organic residue inputs.
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Current estimates of soil C storage potential are based on models or factors that assume linearity between C input levels and C stocks at steady-state, implying that SOC stocks could increase without limit as C input levels increase. However, some soils show little or no increase in steady-state SOC stock with increasing C input levels suggesting that SOC can become saturated with respect to C input. We used long-term field experiment data to assess alternative hypotheses of soil carbon storage by three simple models: a linear model (no saturation), a one-pool whole-soil C saturation model, and a two-pool mixed model with C saturation of a single C pool, but not the whole soil. The one-pool C saturation model best fit the combined data from 14 sites, four individual sites were best-fit with the linear model, and no sites were best fit by the mixed model. These results indicate that existing agricultural field experiments generally have too small a range in C input levels to show saturation behavior, and verify the accepted linear relationship between soil C and C input used to model SOM dynamics. However, all sites combined and the site with the widest range in C input levels were best fit with the C-saturation model. Nevertheless, the same site produced distinct effective stabilization capacity curves rather than an absolute C saturation level. We conclude that the saturation of soil C does occur and therefore the greatest efficiency in soil C sequestration will be in soils further from C saturation.
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Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily--and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.
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More than twice as much carbon is held in soils as in vegetation or the atmosphere, and changes in soil carbon content can have a large effect on the global carbon budget. The possibility that climate change is being reinforced by increased carbon dioxide emissions from soils owing to rising temperature is the subject of a continuing debate. But evidence for the suggested feedback mechanism has to date come solely from small-scale laboratory and field experiments and modelling studies. Here we use data from the National Soil Inventory of England and Wales obtained between 1978 and 2003 to show that carbon was lost from soils across England and Wales over the survey period at a mean rate of 0.6% yr(-1) (relative to the existing soil carbon content). We find that the relative rate of carbon loss increased with soil carbon content and was more than 2% yr(-1) in soils with carbon contents greater than 100 g kg(-1). The relationship between rate of carbon loss and carbon content is irrespective of land use, suggesting a link to climate change. Our findings indicate that losses of soil carbon in England and Wales--and by inference in other temperate regions-are likely to have been offsetting absorption of carbon by terrestrial sinks.
Article
The concept of soil organic C (SOC) saturation suggests that the quantity of stable SOC is limited and determined by the amount of fine particles (clay + fine silt, Clay + fSilt). The difference between the theoretical SOC saturation value and the measured SOC one for the fine fraction corresponds to the soil's saturation deficit and may represent the potential for SOC sequestration in a stable form. We calculate the saturation deficit of French arable soils based on the national soil test database and using the saturation equation. For the whole database (n = 1 454 633), the median saturation deficit was 8.1 gC/kg and this generally increased with the Clay + fSilt content to reach a maximum of 500 g/kg. National mapping of the SOC saturation deficit allowed investigation of spatial variation and controlling factors. Saturated soils were found in localities with specific land use (grassland, meadows) or farming systems (livestock production with high manure production). Smaller deficits occurred at higher altitudes, probably due to the combined effect of cooler temperature and the presence of meadows. Some very sandy soils appeared to be almost saturated, largely due to their very small fine fraction. Soils in the highly cultivated plains in the northern half of the country had a significant saturation deficit. Soils in the southern part of the country had the highest saturation deficit because of the combined effects of climatic factors (low production, high temperature) and land use (vineyards, orchards). Analysis of communal data revealed significant correlations at the national level with Clay + fSilt (r = 0.59), pH (r = 0.44) but also with the proportion of grassland in the cultivated area (r = -0.47). Some areas had apparent oversaturation which may be due to uncertainty associated with the theoretical C saturation equation because of overestimation of the stable soil C fraction. Mapping the C saturation deficit at the national scale demonstrates the influence of climate, soil parameters and land use on the SOC stabilization potential and indicates that a significant proportion of agricultural soils have potential for further SOC storage.
Article
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.
Article
This review explores the role of land use and land use change as a determinant of the soil's ability to sequester and store carbon in the UK. Over 95 percent of the UK land carbon stock is located in soils which are subjected to a range of land uses and global changes. Land use change can result in rapid soil loss of carbon from peatlands, grasslands, plantation forest and native woodland. Soil carbon accumulates more slowly (decadal) but gains can be made when croplands are converted to grasslands, plantation forest or native woodland. The need for land for food production and renewable forms of energy could have considerable influence on UK soil carbon storage in the future. There is a need to recognise the risk of soil carbon losses occurring when land use change to increase carbon storage is offset by compensatory land use conversions elsewhere that result in net carbon release. The protection of peatland and other organic soil carbon stocks, and the management of cropland, grassland and forest soils to increase carbon sequestration, will be crucial to the maintenance of the UK carbon balance. It will be necessary to develop policy to balance trade-offs between soil carbon gains with other land use priorities. These include the sustainable production of food, bio-energy and fibre crops and livestock, water quality and hydrology, greenhouse gas emission control and waste management, all of which are underpinned by the soil.
Article
Soil structure is known to stabilise organic carbon (Corg), as it acts as physical barrier between the decomposing microorganisms and the substrates. It is, however, not fully understood how the organic carbon (Corg) and especially fresh material from plants is distributed within the soil structure. The aim of the current study is to investigate the long- and short-term accumulation of Corg in soil macro-aggregates following the 2 main soil structure formation models: hierarchical and gradient development around plant debris. Two types of differently vegetated and tilled silty loam soil were selected for the examination of Corg and δ13C signals within 4 aggregate size classes (
Article
Yearly, per-area carbon sequestration rates are used to estimate mitigation potentials by comparing types and areas of land management in 1990 and 2000 and projected to 2010, for the European Union (EU)-15 and for four country-level case studies for which data are available: UK, Sweden, Belgium and Finland. Because cropland area is decreasing in these countries (except for Belgium), and in most European countries there are no incentives in place to encourage soil carbon sequestration, carbon sequestration between 1990 and 2000 was small or negative in the EU-15 and all case study countries. Belgium has a slightly higher estimate for carbon sequestration than the other countries examined. This is at odds with previous reports of decreasing soil organic carbon stocks in Flanders. For all countries except Belgium, carbon sequestration is predicted to be negligible or negative by 2010, based on extrapolated trends, and is small even in Belgium. The only trend in agriculture that may be enhancing carbon stocks on croplands at present is organic farming, and the magnitude of this effect is highly uncertain. Previous studies have focused on the potential for carbon sequestration and have shown quite significant potential. This study, which examines the sequestration likely to occur by 2010, suggests that the potential will not be realized. Without incentives for carbon sequestration in the future, cropland carbon sequestration under Article 3.4 of the Kyoto Protocol will not be an option in EU-15.
Article
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.
Article
The compilation of a database of soil carbon and land use is described, from which models of soil carbon dioxide emissions across the United Kingdom (UK) can be run. The database gives soil organic carbon, sand, silt and clay contents and bulk densities weighted to reference layers from 0 to 30 cm and from 30 to 100 cm depths. The data are interpolated from information on soil types and land use on a 1 km grid across the UK and are used to estimate soil carbon stocks. For 1990, the baseline year for the Kyoto Protocol on carbon emissions, the estimate is 4562 Tg soil organic carbon in the top 1 m of soil across the UK, with an average density of 18 kg m−2. The data can be reported by layer (e.g. 54% in topsoils) and country (e.g. 48% in Scotland) as well as by soil and land type.
Article
Various estimates have suggested that the peatlands of Scotland are a significant deposit of fixed carbon. However, these have been based upon rather imprecise estimates of peat depth. Using previously unused archived data, we have mapped peat depth across the country and then used these values to obtain an improved value of the total carbon stock within peatlands, as well as indicating their spatial distribution. We included peat deposits that occur in combination with other soils in soil map units other than ‘blanket’ or ‘basin’ peat. We obtained an area-weighted mean peat depth of 2.0 m, which is slightly shallower than previous estimates. Using values of bulk density and % carbon from the Scottish soils database, the total peatland carbon stock came to 1620 Mt, which represents 56% of the total carbon in all Scottish soils.
Article
We have measured total soil organic carbon (SOC), dissolved organic carbon (DOC), and microbial lipid contents (as indices of microbial biomass and community structure), and their distributions to 60cm depth in soils from replicated medium-term (2003–2008) experimental arable plots subject to different tillage regimes in Scotland. The treatments were zero tillage (ZT), minimum tillage (MT; cultivation to 7cm), the conventional tillage (CT) practice of ploughing to 20cm, and deep ploughing (DP) to 40cm depth. In the 0–30cm depth range, SOC content (corrected for bulk density differences between tillage treatments) was greatest under ZT and MT, but over 0–60cm depth the SOC contents of these treatments were similar to the CT and DP treatments. DOC concentrations declined with increasing depth in ZT and MT above 20cm, but there were no significant differences with depth in the CT and DP treatments. Beneath 20cm, there was little change in DOC concentration with depth for all treatments, although for the MT treatment, there was less DOC beneath the depth of cultivation. The total microbial biomass decreased with increasing depth over the 0–60cm range in the ZT and MT treatments, whereas it decreased with depth only below 30–40cm in the CT and DP treatments. The microbial biomass was significantly different only between 0–5cm in the ZT, CT and DP treatments, but not for other depths between all treatments. The bacterial biomass was greater in the ZT treatment than in MT, CT and DP near the soil surface, but not significantly different over the whole profile (0–60cm). The fungal biomass decreased with depth in the ZT and MT treatments over the whole 0–60cm depth range, whereas it decreased with depth only below 20cm in the CT and DP treatments. KeywordsTillage regime-Soil organic carbon-Dissolved organic carbon-Microbial Biomass-Bacterial biomass-Fungal biomass
Article
Historically, soils have always underpinned civilisation. Their role is fundamental to the provision of food and water, along with a wide range of ecosystem goods and services. Soils are arguably the most complex systems on Earth, and are intimately linked to human security and the integrity of the wider environment. In this paper we propose 18 ecosystem services that are critical for soils and land use in the UK. Soils are extremely heterogeneous and not all soils can fulfil the full spectrum of services required for the future of the UK, so there is a need to protect their multifunctional attributes in order to preserve national and international natural capital. There are concerns that anthropogenically induced changes in land use or management will result in soils not being utilised to provide the functions to which they are best suited. For example, soils primarily suited for food supply may be given over to provide a platform for construction. This is an all-pervading and recurring concern and highlights the importance of critical decisions, thresholds and potential ‘tipping points’. Once critical soil functions are lost they are irrecoverable, potentially for millennia, representing a loss of resource that is fundamental to the UK's national livelihood and well-being. Pressures from changes in climate and to the Earth system will bring about complex and systematic change to soils and their abilities to provide essential functions. We therefore recommend national needs for ensuring the sustainability for soils and future land use in the UK. They are to maintain the long-term base for soil science through education and intellectual investment, including communication of the value of soils and land as natural capital; to manage soil resources so that multi-functionality prevails and critical tipping points are avoided; to audit the national soil resource through soil mapping; preparation of appropriate databases and provision of long-term monitoring networks and observatories; and to synthesise adaptable predictive frameworks for soil system science through integrated modelling.
Application of Soil Organic Carbon Status Indicators for policy-decision making in the EU Distribution of soil carbon and microbial biomass in arable soils under different tillage regimes
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