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Soil organic carbon sequestration in agroforestry systems. A review

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Abstract

The increase in atmospheric carbon dioxide (CO2) concentrations due to emissions from fossil fuel combustion is contributing to recent climate change which is among the major challenges facing the world. Agroforestry systems can contribute to slowing down those increases and, thus, contribute to climate change mitigation. Agroforestry refers to the production of crop, livestock, and tree biomass on the same area of land. The soil organic carbon (SOC) pool, in particular, is the only terrestrial pool storing some carbon (C) for millennia which can be deliberately enhanced by agroforestry practices. Up to 2.2 Pg C (1 Pg = 10(15) g) may be sequestered above- and belowground over 50 years in agroforestry systems, but estimations on global land area occupied by agroforestry systems are particularly uncertain. Global areas under tree intercropping, multistrata systems, protective systems, silvopasture, and tree woodlots are estimated at 700, 100, 300, 450, and 50 Mha, respectively. The SOC storage in agroforestry systems is also uncertain and may amount up to 300 Mg C ha(-1) to 1 m depth. Here, we review and synthesize the current knowledge about SOC sequestration processes and their management in agroforestry systems. The main points are that (1) useful C sequestration in agroforestry systems for climate change mitigation must slow or even reverse the increase in atmospheric concentration of CO2 by storing some SOC for millennia, (2) soil disturbance must be minimized and tree species with a high root biomass-to-aboveground biomass ratio and/or nitrogen-fixing trees planted when SOC sequestration is among the objectives for establishing the agroforestry system, (3) sequestration rates and the processes contributing to the stabilization of SOC in agroforestry soils need additional data and research, (4) retrospective studies are often missing for rigorous determination of SOC and accurate evaluation of effects of different agroforestry practices on SOC sequestration in soil profiles, and (5) the long-term SOC storage is finite as it depends on the availability of binding sites, i.e., the soil's mineral composition and depth. Based on this improved knowledge, site-specific SOC sequestering agroforestry practices can then be developed.

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... Soil organic carbon (SOC) is a cornerstone of soil health and ecosystem sustainability, playing a critical role in maintaining soil fertility, supporting biological activity, and regulating the global carbon cycle. SOC stability, de ned as its resistance to decomposition and loss, is pivotal for ensuring long-term carbon sequestration and mitigating climate change impacts (Lorenz and Lal 2014;Das 2023). Among the mechanisms contributing to SOC stability, soil aggregation stands out as a protective barrier against microbial decomposition, enhancing nutrient retention and soil physical properties (Keller and Phillips 2019; Augusto and Boca 2022). ...
... Further, the dynamics of SOC in agroforestry systems are in uenced by various factors, including vegetation characteristics, climate, and soil management practices. The interplay between these factors determines how carbon is stored, stabilized, and decomposed over time (Lorenz and Lal 2014). Temperature, in particular, plays a critical role in SOC dynamics by affecting microbial activity and organic matter decomposition rates. ...
... However, the effectiveness of agroforestry systems in stabilizing SOC depends on site-speci c factors, such as soil type, climate, and management practices. Despite the advancements in understanding these dynamics, knowledge gaps remain in quantifying the effects of speci c agroforestry systems on SOC stability across soil depths, thermal conditions, and management regimes (Lorenz andLal 2014, Das 2023). This study addresses these gaps by exploring the stability of SOC pools under varying land-use scenarios and thermal conditions in agroforestry systems. ...
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Agroforestry systems play a critical role in enhancing soil organic carbon (SOC) stability and mitigating climate change by integrating trees and crops to improve soil fertility and carbon sequestration. This study investigates the SOC stability, aggregate dynamics, and temperature sensitivity of SOC mineralization across four agroforestry systems ( Michelia oblonga, Parkia roxburghii, Alnus nepalensis , and Pinus kesiya ). Tree traits, soil properties, and aggregate characteristics were analyzed alongside a 60-day incubation experiment under three temperature regimes (25°C, 30°C, and 35°C). The results revealed the SOC mineralization significantly varied amongst the agroforestry systems with highest value in M. oblonga (25.59 mg CO 2 g − 1 ) and lowest in A. nepalensis (20.39 mg CO 2 g − 1 ). Macroaggregates consistently showed higher SOC concentrations and biochemical indicators, such as polysaccharides and total glomalin-related soil proteins (TG-RSP), compared to microaggregates and bulk soil. The temperature and aggregate sizes statistically influenced the SOC mineralization rates, with noticeable interaction effect. SOC mineralization rates increased with temperature, but Alnus nepalensis exhibited the highest temperature sensitivity (Q 10 = 0.955 and activation energy = 24.25 kJ mol − 1 ), highlighting its resilience to thermal stress. Strong positive correlations were observed between soil aggregate stability and soil biochemical indicators such as SOC, polysaccharides and TG-RSP of bulk soil and aggregates. Temporal trends indicated that carbon mineralization peaked at 30 days before stabilizing, reflecting the decomposition of labile carbon pools. These findings highlight the critical role of tree traits, soil aggregates, and thermal stability in driving SOC retention in agroforestry systems.
... Diante do exposto, os SAFs representam uma solução promissora para os desafios enfrentados pela agricultura no semiárido brasileiro, oferecendo uma alternativa sustentável, integrando árvores, cultivos e pecuária de forma a recuperar a fertilidade do solo, aumentar a resiliência às mudanças climáticas e promover a regeneração dos ecossistemas locais, contribuindo as comunidades rurais. As revisões sobre tema tem se concentrado na análise do sequestro de carbono orgânico em sistemas agro florestais (Lorenz & Lal, 2014), o efeito sobre a fauna e suas funções (Marsden et al., 2020), o desenvolvimento do sistema agroflorestal tropical (Mahmud et al., 2021), a recuperação do solo (Moraes & Cavichiolli, 2022), avaliação dos indicadores de qualidade do solo (Fahad et al., 2022), a avaliação da implantação de SAFs em propriedades rurais (É. B. Silva et al., 2019) e a relação com autonomia dos produtores (Frederico & Moral, 2022). ...
... Os SAFs desempenham um papel crucial no ciclo do carbono devido à sua capacidade de aumentar o estoque de carbono no solo, oferecendo um potencial de sequestro superior ao das culturas agrícolas e pastagens. Como bem destaca Lorenz & Lal (2014) a inclusão de árvores, especialmente as fixadoras de nitrogênio, pode aumentar especificamente o armazenamento de sequestro de carbono do solo em sistemas agroflorestais. Esta eficácia resulta da contribuição de biomassa tanto acima do solo quanto em profundidade, através de sistemas radiculares extensos das árvores (Ma et al., 2022;Maharjan et al., 2024;Ribeiro et al., 2019). ...
... Contribuindo assim de forma eficiente para a mitigação climática, por possibilitar o sequestro de carbono mais estável no solo e consequentemente menor probabilidade de decomposição do mesmo, principalmente pela interação das árvores e culturas, resultando em aumento da biomassa e acúmulo de matéria orgânica, em um sistema de uso de terra a longo prazo resultando no armazenamento do carbono por um período prolongado (Guillot et al., 2021;Hübner et al., 2021;Lorenz & Lal, 2014). ...
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O semiárido brasileiro tem passado por extensos processos de degradação ambiental, principalmente devido a impactos causados pela atividade agropecuária, desmatamentos e queimadas, apresentando como seu bioma predominante, a Caatinga, o qual possui cerca de 50% da sua paisagem original modificada. O uso de sistemas agroflorestais (SAFs) tem sido abordando na literatura destacando-se como uma forma de exploração sustentável, adotados em diversas regiões ao redor do globo, contudo no semiárido brasileiro, apesar do crescimento de áreas destinadas aos SAFs ter ocorrido no Brasil nos últimos anos, adoção desses sistemas na região semiárida ainda é pouco difundida. Considerando-se os benefícios da adoção dos SAFs onde se destacam a assimilação de carbono e nitrogênio, conservação do solo, redistribuição hidráulica, ciclagem de nutrientes e biodiversidade, e a importância da preservação de áreas do semiárido brasileiro e garantia de segurança alimentar dos produtores, e assim a abordagem econômica e ecológica dos sistemas agroflorestais, objetivou-se com essa revisão enriquecer as discussões sobre esses sistemas, seus benefícios e sua viabilidade, como forma de produção agrícola sustentável e fonte de renda a ser adotada no semiárido brasileiro.
... Box plot includes values between 25 and 75 percentile, the line represents median value. (Andrianarisoa et al., 2016), improved agroecosystems resilience (Hillbrand et al., 2017) and C sequestration both in soil and above-below ground biomass (Ivezić et al., 2022;Lorenz and Lal, 2014;Nair, 2012). Although agroforestry has been recognized as the land-use with the highest potential for C sequestration (IPCC, 2000;Lorenz and Lal, 2014) and is one of the most promising agro ecological solutions for sustainable intensification, studies evaluating SLA in Europe are scarce. ...
... (Andrianarisoa et al., 2016), improved agroecosystems resilience (Hillbrand et al., 2017) and C sequestration both in soil and above-below ground biomass (Ivezić et al., 2022;Lorenz and Lal, 2014;Nair, 2012). Although agroforestry has been recognized as the land-use with the highest potential for C sequestration (IPCC, 2000;Lorenz and Lal, 2014) and is one of the most promising agro ecological solutions for sustainable intensification, studies evaluating SLA in Europe are scarce. From Cardinael et al. (2015Cardinael et al. ( , 2020 we obtained a median ΔSOC REL of 0.25 Mg C ha − 1 yr − 1 compared to control agricultural fields. ...
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Carbon farming has been recently proposed as an effective measure for climate change mitigation through carbon (C) sequestration or C emissions reduction. In order to identify and estimate the climate change miti- gation potential of carbon farming practices on European croplands we conduct a systematic review on both relative and absolute annual soil organic carbon (SOC) stock change (ΔSOCREL; ΔSOCABS) related to single and combined agroecological practices tested on mineral soils at a minimum of 0–30 cm and up to 150 cm soil depth whenever data were available. We used the term ΔSOCREL for SOC stock changes determined by the paired comparison method and the term ΔSOCABS for those calculated using the SOC stock difference method. We compiled a dataset with more than 700 records on SOC change rates representing 12 carbon farming practices. Mean ΔSOCREL in Mg C ha−1 yr−1 at 0–30 cm soil depth were collected for cover crops (0.40 ± 0.32), organic amendments (0.52 ± 0.47 and 0.38 ± 0.37 when the control is respectively unfertilized or liquid organic amendment), crop residue maintenance (0.14 ± 0.06), improved rotations (0.21 ± 0.16), reduced soil distur- bance (0.24 ± 0.34), silvoarable systems (0.21 ± 0.08), organic (0.9 Mg ± 0.25) and conservation management (0.78 ± 0.62), set-aside (0.75 ± 0.68 and −0.39 ± 0.50 when the control is respectively cropland or pasture/ grassland), cropland conversion into permanent grassland (0.79 ± 0.47), poplar plantations (0.25 ± 0.68 and −0.85 ± 0.53 when established on cropland or pasture/grassland). SOC sequestration was detected only for organic amendments, cover crops, poplar plantations, conservation management, organic management, and combined carbon farming practices for which we estimated a median ΔSOCABS ranging between 0.32 and 0.96 Mg C ha−1 yr−1 at 0–30 cm. The ΔSOCABS observed at 0–30 cm soil depth from cropland conversion into short rotation forestry resulted in an increase of C, while negative values were observed when the control was grassland. Cropland conversion into permanent grassland or pasture showed positive ΔSOCREL at 0–30 and 0–90 and 0–100 cm soil depth. Reduced soil disturbance full soil profile assessment at 0–50 cm soil depth completely counterweighted any SOC stock increase found in topsoil at 0–30 and 0–40 cm soil depth, therefore resulting in no net climate benefit. Conservation management, organic management, and combining cover crops with organic amendments are the most effective strategies shifting arable land from C source to net sink, with median ΔSOCABS at 0–30 cm soil depth of 0.63, 0.91 and 0.96 Mg C ha−1 yr−1, respectively. Permanent grasslands and pastures were negatively affected by any type of land-use change, at least in topsoil. Natural ecological successions after cropland abandonment (20-year set-aside), or arable land conversion into poplar plantations and grassland promote relative SOC stock annual increase by 1.08, 0.77 and 0.33 at 0–30 cm respectively, while the net climate benefit remains unclear when subsoils are assessed
... In addition to its benefits for the environment, agroforestry meets nearly half of the requirement for fuelwood, 65% of the demand for small timber, 70 -80% of the demand for raw material for plywood, 60% of the need for raw materials for paper pulp and 10-11% of the demand for green fodder for livestock (NRCAF, 2013) [17] . One of the major problems facing the world right now is the current climate change, which is being exacerbated by emissions from the burning of fossil fuels (Lorenz and Lal, 2014) [15] . A large and constantly growing population need for fuel, food, lumber and other forest products is being met from a smaller area of forest at a slower rate, which makes it more challenging (Singh, 2020) [29] . ...
... In addition to its benefits for the environment, agroforestry meets nearly half of the requirement for fuelwood, 65% of the demand for small timber, 70 -80% of the demand for raw material for plywood, 60% of the need for raw materials for paper pulp and 10-11% of the demand for green fodder for livestock (NRCAF, 2013) [17] . One of the major problems facing the world right now is the current climate change, which is being exacerbated by emissions from the burning of fossil fuels (Lorenz and Lal, 2014) [15] . A large and constantly growing population need for fuel, food, lumber and other forest products is being met from a smaller area of forest at a slower rate, which makes it more challenging (Singh, 2020) [29] . ...
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Agroforestry is a classical long-standing technique and a significant aspect of subsistence farming, which gained popularity as a commercial and beneficial land use throughout the world in recent years. Approximately, 1.2 billion people depend directly on agroforestry products and services viz. fuelwood, timber, poles, food, fodder etc. In Shiwalik Himalayan region, traditional agroforestry practices play significant role in sustainable livelihoods of the people through fulfilling their daily needs. The current article provides concise description of the different agroforestry systems practiced in the Shiwalik Himalayan region, together with information on their biomass production, economic benefits and carbon sequestration potential. The various agroforestry systems that farmers prefer and practiced in the region are Agri-Silviculture (AS), Agri-Horticulture (AH), Agri-Silvi-Horticulture (ASH), Agri-Silvi-Pastoral (ASP), Silvi-Pastoral (SP), Pastoral-Silviculture (PS), Agri-Horti-Silviculture (AHS), Pastoral-Horticulture (PH), Horti-Pastoral (HP) and Pastoral-Horti-Silviculture (PHS). In terms of biomass production, the production potential of agroforestry systems ranged from 4.24 t ha-1 to 47.45 t ha-1 whereas the net economic returns varied from Rs 5,772 ha-1 yr-1 to Rs 2,97,953 ha-1 yr-1 and the B:C ratio from 1.38 to 3.55 based on the types of components used, associated costs incurred and returns realized. Moreover, the carbon stock capacity among practiced agroforestry systems expands from 1.91 t ha-1 to 21.35 t ha-1. Overall, agroforestry is a prominent land use system in Shiwalik region of Himalayan in India which is gaining more interest among farmer due to its higher net returns in all the three categories of farmers. Nevertheless, agroforestry usually stores more carbon than monoculture farming and farmers can also earn carbon credits by trading the carbon captured in agroforestry systems on international markets in the climate change scenario.
... On a global scale, soil plays a vital role by providing food, clean water, and habitats for biodiversity, while also contributing to climate resilience. It supports cultural heritage and landscapes, but remains a fragile resource that must be carefully managed and protected for future generations [1,2]. Soil serves important functions, such as producing sufficient quantities of nutritious and safe food, feed, fiber, and other biomass for industries. ...
... It also regulates and stores water, replenishes aquifers, purifies contaminated water, and mitigates the effects of droughts and floods, thereby aiding in climate change adaptation. Additionally, soil captures carbon from the atmosphere through the process of photosynthesis, playing a key role in climate mitigation [1,2]. However, human activities, often unsustainable, can have a negative impact on soils. ...
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Soils play a crucial role in the protection, management, and ecological understanding of the La Moraña region, located in Ávila province, Central Spain, which has a moderate population, traditional agriculture, livestock farming, and low industrial activity, resulting in relatively low environmental degradation. The region’s soils often experience prolonged water stagnation, influencing its agronomy, ecology, and economy. This study aimed to estimate and understand the soil’s role in the C sequestration of an agrosilvopastoral system under conditions of temporary water stagnation and different land uses. The results showed that ryegrass-magaza and Pinus pinaster show more content in soil carbon sequestration storage (98.7 and 92.4 Mg per hectare) compared to the adjacent degraded rangeland (75.8 and 63.9 Mg ha−1). Arenosols exhibited a higher total amount of SOC stocks. The soil profile with ryegrass sequestered more nitrogen (9.7 Mg ha−1) than other land uses; moreover, Arenosols have a lower nitrogen sequestration capacity even in low-forest conditions. The study highlights significant differences in carbon accumulation due to the management practices, temporary water layers, and parent material.
... Bárcena (2014) [46] examined soil carbon stocks and influencing factors in reforestation, finding that the recovery process is slower in Northern Europe compared to tropical and temperate regions, with forest age, prior land use, forest type, and soil depth affecting carbon storage capacity. Lorenz (2014) [47] analyzed the capacity of agroforestry systems to increase soil carbon storage, highlighting its positive impacts on sustainable agriculture and environmental protection. ...
... Bárcena (2014) [46] examined soil carbon stocks and influencing factors in reforestation, finding that the recovery process is slower in Northern Europe compared to tropical and temperate regions, with forest age, prior land use, forest type, and soil depth affecting carbon storage capacity. Lorenz (2014) [47] analyzed the capacity of agroforestry systems to increase soil carbon storage, highlighting its positive impacts on sustainable agriculture and environmental protection. ...
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Forests are one of the largest terrestrial ecosystems on Earth, absorbing carbon dioxide from the atmosphere through photosynthesis and storing it as organic carbon, thereby mitigating global warming. Conducting bibliometric analysis of forest carbon storage can identify current research trends and hot issues in this field, providing data support for researchers and policy makers. This review article provides a comprehensive bibliometric analysis of global forest carbon storage research, using databases from the Web of Science Core Collection. CiteSpace software (6.2.6 version) was employed to visualize and analyze the data, focusing on key researchers, institutions, and countries, as well as major research themes and emerging trends. The main findings are as follows: (1) Since the 21st century, the publication volume in this field has been increasing, with the United States and China being the top contributors. (2) There is active collaboration among key authors, institutions, and countries, with a notable close-knit network centered around French author Philippe Ciais. This group includes nearly half of the field’s authors and many of them are crucial for advancing research in this field. (3) Cluster and citation burst analyses suggest that future research will focus more on the impact of forest management policies on carbon stocks, with particular attention to the roles of northern temperate forests and mangroves in global carbon storage. These findings provide valuable insights into the current state and future directions of forest carbon storage research. This article is instrumental in elucidating the role of forest ecosystems within the global carbon cycle, evaluating the impacts of anthropogenic activities on forest carbon stocks, and informing the development of effective climate change mitigation strategies.
... Intercropping can also be considered. Studies have shown that intercropping changes the characteristics of aggregates and increases the content of organic carbon in aggregates [33]. Therefore, we can adopt the above measures to realize the harmonious development of man and nature in this area, which is of great significance. ...
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The organic carbon pool in the field is one of the important carbon pools in the ecosystem. This study explored the changes in soil organic carbon fractions and their influencing mechanisms under different cultivation years of jujube trees in the sandy area. This study measured the bulk density, total porosity, water content, pH, salt content, organic matter, major elements, trace elements, and organic carbon fractions of soil in jujube orchards with cultivation years of 2 years, 4 years, 6 years, 8 years, and 10 years, and analyzed the influencing mechanism of physical and chemical properties on soil organic carbon fractions through structural equation modeling. The results showed that soil physical properties were beneficial to plant growth with the increase in limited planting years. Nitrogen, phosphorus, potassium, and other elements were highest in different soil layers in 6–8 years, and then their contents gradually decreased. Soil organic carbon content increased with the increase in different cultivation years and then remained in a stable state. In different soil layers, soil organic carbon is mainly affected by the active soil organic carbon pool (ASCP). The results of this study aim to explore the effect of vegetation on soil improvement in sandy areas and provide theoretical reference for soil restoration and improvement of the organic carbon pool of sandy soil in southern Xinjiang.
... Mg C/ha/year and 30-300 Mg C/ha/year in aboveground biomass and in soil (up to 1 m depth), respectively (Nair et al. 2009). In the next 50 years, practicing sustainable agroforestry can store carbon up to 2.2 Pg (Lorenz and Lal 2014). The use of woody perennials in agricultural land-use systems increases soil microbial diversity and activity, accumulates soil organic C quickly based on the quantity of litter and rate of decomposition (Aguiar et al. 2010), reduces runoff and soil's hydraulic properties, and thus enhances the nutrient cycling (Udawatta et al. 2017). ...
Chapter
Agroforestry systems are present across agricultural landscapes, providing various products such as food, fuel wood, fiber, fodder, and more. Besides these goods, agroforestry delivers crucial ecosystem services that enhance livelihoods. By combining trees and/or shrubs with crops and/or livestock, agroforestry diversifies both agricultural and nonagricultural activities. This method, which involves integrating trees, plants, and livestock on the same land, offers a holistic approach to addressing urgent issues like food security, rural livelihoods, and environmental sustainability. Agroforestry is a well-managed land-use system where agricultural crops are grown alongside woody perennials on the same plot. While modern advancements have improved agroforestry techniques, it is essential to recognize and build upon traditional methods and indigenous knowledge. For agroforestry to be fully effective, collaboration among legislators, scientists, extension agents, farmers, and private sector businesses is necessary. Institutional and governmental frameworks must be established to promote adoption, provide incentives, and create a supportive environment. In conclusion, agroforestry is a promising strategy for improving rural livelihoods, achieving food security, and promoting environmental sustainability. Embracing agroforestry principles and practices will be crucial for ensuring a more resilient and equitable future as we face the challenges of climate change and increasing demands for food and resources.
... Integrating trees and shrubs into agricultural landscapes to enhance soil fertility, biodiversity, and resilience to climate change (Lorenz and Lal 2014). Agroforestry systems provide multiple benefits, including food production, carbon sequestration, and ecosystem services. ...
... En primer lugar, el impacto de las prácticas agroforestales en el secuestro de carbono se consolida como una de sus contribuciones más significativas. Estudios previos destacan que los sistemas agroforestales pueden secuestrar cantidades considerables de carbono en la biomasa aérea y subterránea, superando las capacidades de los sistemas agrícolas convencionales (Mbow et al., 2014;Lorenz & Lal, 2014). Este almacenamiento de carbono no solo contribuye a la reducción de las concentraciones de dióxido de carbono en la atmósfera, sino que también estabiliza los suelos y mejora su calidad, lo cual es esencial para la sostenibilidad de los ecosistemas agrícolas. ...
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The article examines the role of agroforestry practices as key strategies to mitigate and adapt to climate change. Through a literature review, environmental benefits such as carbon sequestration and biodiversity conservation are analyzed, highlighting that agroforestry systems can sequester between 0.2 and 3.1 tons of carbon per hectare annually, depending on species and local conditions. In addition, these practices reduce greenhouse gas emissions by reducing the use of chemical inputs and optimizing resource management. At the socioeconomic level, agroforestry systems diversify sources of income through the production of timber, fruits and environmental services, improving the economic resilience of rural communities. However, their implementation faces challenges related to resource availability, technical training and political support. The article concludes that an integrated approach combining economic incentives, appropriate policy frameworks and the active participation of local communities is essential to maximize their impact. This study provides a comprehensive view on how to integrate agroforestry practices into sustainable strategies to address climate change and promote rural development.
... Globally, agroforestry systems cover about one billion ha and support about 560 million people in developing countries [6]. The system sequesters 1.1 to 2.2 Pg C in the aboveground biomass per year globally over a 50-year period [7]. The Intergovernmental Panel on Climate Change [8] predicted that by 2040, agroforestry in developing countries would have the highest carbon sequestration potential of the land uses analyzed. ...
... Our results showed that there was a loss of C both with the conversion of NF to PA (51.2 Mg ha − 1 ) and with the conversion of PA to AFS (16.5 Mg ha − 1 ). Soil C losses in natural systems altered for agricultural crops occur immediately after conversion, tending to be mitigated with the implementation of agroforestry systems (Lorenz and Lal 2014). ...
Article
Coffee agroforestry systems (AFS) have been shown to enhance soil, which results in a positive impact on above and belowground organic inputs. However, the specific temporal impact of coffee AFS to soil carbon and nitrogen pools remains uncertain. Thus, we aim to answer the following questions: how do soil total carbon (TC) and total nitrogen (TN) stocks respond to different coffee cultivation systems? And to what extent can a coffee AFS contribute to replacing the TC?. We evaluated three coffee cultivation systems (agroforestry system with grevillea – AFS; consortium with banana – CBC; and coffee monoculture – CM). We used two reference systems in order to compare these systems: a native forest (NF) and a pasture (PA). Soil samples were collected at six different depths (0–10, 10–20, 20–40, 40–60, 60–80, 80–100 cm). The samples were then analyzed using an elemental analyzer to determine total carbon (TC) and total nitrogen (TN) levels. An isotope ratio mass spectrometer was used to further assess soil composition by measuring the natural abundance of δ13C and δ15N. The two mixed coffee systems had similar TC stocks in the topsoil to those of NF and PA, while CM had the lowest stock. However, only CBC maintained a similar TC stock to NF and PA at 100 cm depth (on average 140.5 Mg ha− 1). TN stocks followed a similar pattern to TC. It was found that over 70% of soil carbon under AFS and PA was derived from C3 plants. In the upper soil layer, AFS and CBC maintain TC and TN stocks in relation to NF. However, when considering the total stock at 100 cm depth, only CBC (compared to AFS) is able to maintain similar levels to NF. Despite this, AFS has great capacity to replace soil organic carbon, replacing more than 50% of C4 in PA.
... This, in turn, strengthens the contribution of terrestrial ecosystems to the organic carbon (OC) deposited in reservoir sediments, creating a more resilient and sustainable land-water interface (Li et al., 2024a). The integration of trees with crops in agroforestry systems can stabilize the soil and enhance its capacity to capture and retain carbon, thereby reducing the transport of OC into the water systems (Lorenz & Lal, 2014). Secondly, it is essential to improve sewage treatment infrastructure and enhance the management of agricultural runoff (Scheierling et al., 2010). ...
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This study focuses on the sources of organic carbon (OC) in surface sediments of reservoirs in the mountainous regions, as well as their dynamics and contribution mechanisms in the carbon cycle. Spatial variations in organic carbon, n‐alkanes, δ¹³C, and δ¹⁵N were analyzed, and a Bayesian isotope mixing model was applied to quantify the relative contributions of different OC sources. The results indicate that the concentration range of organic carbon in sediments is 0.88%–3.72%. The average concentration of long‐chain n‐alkanes is 3.69 μg/g, accounting for 71.4%, indicating that the main source of organic carbon is allochthonous organic carbon. In addition, the Bayesian mixture model results of carbon and nitrogen isotopes also indicate that allochthonous organic carbon is the main contributor. Specifically, sewage (33.1%), C₃ plants (27.1%), and soil organic carbon (19.9%) were identified as the dominant sources. This research highlights the influence of human activities, such as urbanization and agriculture, on OC dynamics and underscores the role of reservoirs in regulating OC transport. The findings provide critical insights into the mechanisms of OC sequestration in agricultural watersheds and offer valuable guidance for water resource management and ecological protection strategies in mountainous environments.
... This is mainly because SOC is a representative index reflecting soil fertility and soil quality. Many studies have confirmed that SOC has a significant effect on soil properties and crop growth [12,62]. TN and TP are also essential elements that affect plant growth [63][64][65]. ...
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Agroforestry is being promoted as a feasible land use management to improve understory economic benefits. However, there are few studies on species selection and the comprehensive evaluation of soil quality change in rhizoma bletillae (Bletilla striata) agroforestry systems. The soil quality index (SQI) and minimum dataset (MDS) methods can reflect the overall condition and were effective tools for understanding different cultivation systems. In this study, we evaluated the soil quality of four cultivation models (including three agroforestry systems: PeB, moso bamboo (Phyllostachys edulis)–rhizoma bletillae; PoB, plane trees (Platanus orientali)–rhizoma bletillae; CcB, pecan trees (Carya cathayensis)–rhizoma bletillae; and CK, rhizoma bletillae monoculture. The total dataset (TDS) consisted of 15 soil parameters containing physical, chemical, and biological characteristics. The results showed that soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) were finally selected and established as the MDS. Agroforestry could significantly influence soil quality. Compared with CK, the SQI in CcB significantly increased and decreased in PeB and PoB. Soil water content (SWC), nitrate nitrogen (NO3−-N), dissolved organic carbon (DOC), SOC, TN, and TP contents were higher in CcB than in the other cultivation models. Based on various soil indicators and SQI analysis, the CcB was the best in improving soil quality. These findings showed that the soil quality index based on the MDS can be used as an effective indicator for agroforestry systems selection. It provides theoretical guidance for the practice of bionic cultivation and the sustainable management of rhizoma bletillae.
... In sub-Saharan Africa, households' yearly gross revenue from trees is 17% higher (Christiaensen and Demery 2018). Moreover, various agro forestry system mechanisms are chronologically and spatially organized to resemble biological and chemical mechanisms with a reduced need for synthetic materials inputs like compost, weed killers, and agrochemicals, providing essential regula tory services like enhancing soil fertility, preventing erosion, regulating and puri fying water, conserving biodiversity, and sequestering carbon (Lorenz and Lal 2014;HLPE 2019). They contribute to pest populations eradication, a vastly greater variety of microbial activity, and insects that serve as food for birds and as pollinators, among other things, to the preservation of biodiversity. ...
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The UN Sustainable Development Goals must be implemented in all productive landscapes around the world, and agroforestry and sustainable landscape management are crucial tactics for doing so. It is frequently hailed as a viable strategy for reducing the implications of climate change and addressing the negative consequences of unsustainable land-use on capitalism and the ecosystem, and society. Agroforestry is an agro-ecological strategy that includes growing timber commodities, producing in and around forests, raised animals, and working with trees and forests at various sizes. It is more than just "agricultural with trees." In addition to advocating forest farming and backyard gardens as approaches to boosting the utilization of short distribution networks and bridging peri urban, agrarian, and urban communities inside the context of the regenerative and bioeconomy, silvo-pasture should be prioritized as a major climate change moderation decision to decrease wildfires and raise the density of forest cover in cultivated soils (silvo-arable). The 13% of CO2 emissions from the agriculture, forestry, and land-use (AFLOU) sectors that are released into the atmosphere have a significant influence on climate change and planet scorching. The adverse consequences of climate change can be seen globally in the declining biological and man-made ecosystem production. So, Agroforestry techniques can assist diversify food systems, boost economic return, and maximize the use of natural resources in addition to having a favourable influence on the environment. Agroforestry can be used effectively for sustainable landscape management through the following essential aspects: (i) the development of "agroforestry sustainability science"; (ii) recognizing local land-use trends, antiquities, and customs; (iii) Increasing agroforestry for benefits at the landscape level; (iv) encouraging the many benefits of agroforestry to the economy, ecology, society, and culture; (v) encouraging equitable landscape governance; and (vi) assisting in the design and analysis of agroforestry systems as part of the innovation process. The benefits that can be derived from the interaction of agricultural crops and forest trees are tremendous. Agroforestry has many benefits that are relevant to a sustainable production system and way of life.
... In sub-Saharan Africa, households' yearly gross revenue from trees is 17% higher (Christiaensen and Demery 2018). Moreover, various agro forestry system mechanisms are chronologically and spatially organized to resemble biological and chemical mechanisms with a reduced need for synthetic materials inputs like compost, weed killers, and agrochemicals, providing essential regula tory services like enhancing soil fertility, preventing erosion, regulating and puri fying water, conserving biodiversity, and sequestering carbon (Lorenz and Lal 2014;HLPE 2019). They contribute to pest populations eradication, a vastly greater variety of microbial activity, and insects that serve as food for birds and as pollinators, among other things, to the preservation of biodiversity. ...
Chapter
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The UN Sustainable Development Goals must be implemented in all productive landscapes around the world, and agroforestry and sustainable landscape management are crucial tactics for doing so. It is frequently hailed as a viable strategy for reducing the implications of climate change and addressing the negative consequences of unsustainable land-use on capitalism and the ecosystem, and society. Agroforestry is an agro-ecological strategy that includes growing timber commodities, producing in and around forests, raised animals, and working with trees and forests at various sizes. It is more than just “agricultural with trees.” In addition to advocating forest farming and backyard gardens as approaches to boosting the utilization of short distribution networks and bridging peri-urban, agrarian, and urban communitiesinside the context of the regenerative and bioeconomy, silvi-pasture should be prioritized as a major climate change moderationdecision to decrease wildfires and raise the density of forest cover in cultivated soils (silviarable). The 13% of CO2 emissions from the agriculture, forestry, and land-use (AFLOU) sectors that are released into the atmosphere have a significant influence on climate change and planet scorching. The adverse consequences of climate change can be seen globally in the declining biological and man-made ecosystem production. So, Agroforestry techniques can assist diversify food systems, boost economic return, and maximize the use of natural resources in addition to having a favourable influence on the environment. Agroforestry can be used effectively for sustainable landscape management through the following essential aspects: (i) the development of “agroforestry sustainability science”; (ii) recognizing local land-use trends, antiquities, and customs; (iii) Increasing agroforestry for benefits at the landscape level; (iv) encouraging the many benefits of agroforestry to the economy, ecology, society, and culture; (v) encouraging equitable landscape governance; and (vi) assisting in the design and analysis of agroforestry systems as part of the innovation process. The benefits that can be derived from the interaction of agricultural crops and forest trees are tremendous. Agroforestry has many benefits that are relevant to a sustainable production system and way of life.
... (4) Agroforestry: The CDR potential increases with increasing tree density (Nair et al., 2009;Hamon et al., 2009). Tree species influence the potential; broadleaf species show a higher SOC increase rate than coniferous trees (Mayer et al., 2022), and high species diversity has a positive effect (Nair et al., 2009;Hamon et al., 2009;Lorenz and Lal, 2014). With increasing age of the agroforestry stand, carbon stocks increase until a new steady state/equilibrium is reached; the carbon stock increase rate decreases with stand age (Feliciano et al., 2018;Hamon et al., 2009). ...
... The deep root systems of trees also contribute to soil carbon sequestration by depositing carbon deeper into the soil profile, where it is less susceptible to decomposition. Additionally, the presence of trees and perennial plants improves soil structure and increases soil organic matter content, further enhancing the capacity of the soil to sequester carbon (Lorenz & Lal, 2014). ...
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Carbon Sequestration and Agriculture: Opportunities and Challenges
... Studies have shown that high-quality agroforestry composite ecosystems are not only able to provide food, timber, and other products but also ecological services [52,53]. For example, agroforestry ecosystems can increase organic carbon storage and mitigate climate change [54,55], increase biodiversity [51], mitigate the global impact of nitrogen cycle leakage in farmland [56], and improve soil health [57] and agricultural landscapes [58]. However, studies on agroforestry ecosystems in karst areas are scarce. ...
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Amid global rural decline, the main approach to rural revitalization (RR) is to transform rural ecological resources into development advantages by means of ecological product value realization (EPVR). The fragility of the karst ecological environment limits the development of the karst countryside, and agroforestry is an important way to achieve the ecological protection and economic development of the karst countryside. At present, research on EPVR and RR is rapidly developing. Although there is an increasing number of publications on EPVR and RR separately, the literature on their comprehensive analysis is lacking, and how the karst agroforestry ecosystem can be improved is unclear. The objective of this is to provide an overview of the current research status and challenges of EPVR and RR in order to optimize agroforestry ecosystems in karst desertification control (KDC). This paper systematically analyzed 263 relevant articles on EPVR and RR, and the results are as follows: (1) The number of studies increased exponentially after 2017. The research has primarily focused on the relationship between EPVR and RR, as well as the EPVR and the formation mechanisms of the eco-industry and value accounting of eco-products, which account for 95.53% of the total literature. China has published the most research in this area. At the intercontinental scale, this research is mainly concentrated in East Asia, Europe, and North America. (2) The main progress and landmark achievements in the research on EPVR and RR are summarized. Four key scientific questions that need to be addressed in the future are presented. (3) The above information highlights the three key areas for improving the agroforestry ecosystem in karst desertification control (KDC): the value accounting of eco-products, EPVR, and RR. This study found that EPVR and RR can improve the karst agroforestry ecosystem and further promote rural development, providing significant insights for the overall revitalization of rural areas worldwide and the scientific control of karst desertification.
... Besides, N 2 -fixing trees and shrubs in most of our study sites substantially enhanced SOC storage. Furthermore, the massive root arrangement of mixed stands can recover soil nutrients from below the rooting sphere [79]. Plant diversity has also been suggested to influence soil microbial community composition, soil nutrients (SOC, N, P) content and pH as well [80] where various mixed plants are assembled. ...
... ). Deep-rooted trees in agroforestry improve groundwater quality by absorbing nutrients that have leached beyond the crop rooting zone(Kumar et al., 2020). Also, a number of studies demonstrated that AF contributes to climate change mitigation by sequestering carbon in trees and soil(Abbas et al., 2017;Lorenz and Lal, 2014;). Thus, through multiple synergistic mechanisms, agroforestry plays a crucial role in augmenting the natural capacity of landscapes to effectively manage and retain water. ...
... In addition, the relative abundance of the aromatic compound degradation functional group is reduced so that the degradation rate of aromatic compounds, which are an important part of soil organic carbon, may contribute to the long-term fixation of carbon [50]. The increase in soil carbon sequestration leads to a decrease in carbon dioxide emissions, slows global warming, and helps increase soil organic carbon levels [51,52]. ...
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In order to reduce the actual impact of a saline–alkali environment on maize production in semi-arid areas, it is particularly important to use the combined fertilization strategy of Trichoderma microbial fertilizer and nitrogen fertilizer. The purpose of this study was to investigate the effects of different concentrations of nitrogen fertilizer combined with Trichoderma on improving the structural characteristics and ecological functions of maize rhizosphere microbial community in semi-arid saline–alkali soil. Through the microbiome analysis of maize rhizosphere soil samples with 60 kg N·ha−1 (N1) and 300 kg N·ha−1 (N2) nitrogen fertilizer combined with Trichoderma (T1) and without Trichoderma (T0), we found that the combination of Trichoderma and different concentrations of nitrogen fertilizer significantly affected the structure of bacterial and fungal communities. The results of this study showed that the combination of Trichoderma and low-concentration nitrogen fertilizer (N1T1) could improve soil nutritional status and enhance its productivity potential, revealing the relationship between beneficial and harmful fungal genera, microbial diversity and abundance, and crop biomass, which is of great significance for improving agricultural production efficiency and sustainable development.
... Agroforestry can boost biomass carbon reserves since tree biomass comprises 46-51 % carbon (Lorenz & Lal, 2014;Kim et al., 2016). Studies have demonstrated that agroforestry sequesters carbon in biomass and soil at global and tropical levels. ...
Article
The conservation of endangered native species and climate change are currently the two most pressing environmental problems on the planet. Therefore, the general objective of the review was to synthesize evidence of the contributions of agroforestry systems to the conservation of native species, carbon sequestration, and livelihood benefits in Ethiopia. A total of 104 publications from 2000 to 2024 publication years were used to provide available evidence and research gaps on agroforestry contribution to native species conservation (n=21), carbon sequestration (n=33), and livelihood benefits (n=35) in Ethiopia. Furthermore, 38 papers from other parts of the world were used to support ideas and relevant evidence linked to the title. The review's findings confirm that agroforestry can serve as in-situ conservation for endangered native species including Cordia africana Lam., Hagenia abyssinica (Bruce) J.F. Gmel., Acacia abyssinica Hochst. ex Benth, Croton macrostachyus Hochst. ex Delile, Ficus sur Forssk and Faidherbia albida (Delile) A. Chev. The review systematic review indicated that agroforestry systems store an average of 40.04 ± 10.4 Mg C ha-1 in biomass and 68.9 ± 9.9 Mg C ha-1 in soil in Ethiopia. Hence, the above-ground carbon was highest for coffee-based agroforestry (17.12 ± 6.3 Mg ha −1) followed by homegarden (16.6 ± 3.2 3 Mg ha −1) and woodlot (7.1 ± 1.09 Mg ha −1). Fuelwood, food, fodder, income, timber, fruits, and poles for construction were the main benefits of livelihood; which have been reported in 37, 30, 26, 25, 23, and 20,18 published articles, respectively. Empirical studies show that an agroforestry system, which can significantly reduce the vulnerabilities of households and store a large amount of carbon dioxide in the atmosphere, is an important strategy for climate adaptation and mitigation. Moreover, further scientific research on agroforestry on the sustainability of agroforestry is needed from responsible bodies in Ethiopia.
... Agroforestry can boost biomass carbon reserves since tree biomass comprises 46-51 % carbon (Lorenz & Lal, 2014;Kim et al., 2016). Studies have demonstrated that agroforestry sequesters carbon in biomass and soil at global and tropical levels. ...
Article
Full-text available
The conservation of endangered native species and climate change are currently the two most pressing environmental problems on the planet. Therefore, the general objective of the review was to synthesize evidence of the contributions of agroforestry systems to the conservation of native species, carbon sequestration, and livelihood benefits in Ethiopia. A total of 104 publications from 2000 to 2024 publication years were used to provide available evidence and research gaps on agroforestry contribution to native species conservation (n=21), carbon sequestration (n=33), and livelihood benefits (n=35) in Ethiopia. Furthermore, 38 papers from other parts of the world were used to support ideas and relevant evidence linked to the title. The review’s findings confirm that agroforestry can serve as in-situ conservation for endangered native species including Cordia africana Lam., Hagenia abyssinica (Bruce) J.F. Gmel., Acacia abyssinica Hochst. ex Benth , Croton macrostachyus Hochst. ex Delile, Ficus sur Forssk and Faidherbia albida (Delile) A. Chev . The review systematic review indicated that agroforestry systems store an average of 40.04 ± 10.4 Mg C ha ⁻¹ in biomass and 68.9 ± 9.9 Mg C ha ⁻¹ in soil in Ethiopia. Hence, the above-ground carbon was highest for coffee-based agroforestry (17.12 ± 6.3 Mg ha ⁻¹ ) followed by homegarden (16.6 ± 3.2 3 Mg ha ⁻¹ ) and woodlot (7.1 ± 1.09 Mg ha ⁻¹ ). Fuelwood, food, fodder, income, timber, fruits, and poles for construction were the main benefits of livelihood; which have been reported in 37, 30, 26, 25, 23, and 20,18 published articles, respectively. Empirical studies show that an agroforestry system, which can significantly reduce the vulnerabilities of households and store a large amount of carbon dioxide in the atmosphere, is an important strategy for climate adaptation and mitigation. Moreover, further scientific research on agroforestry on the sustainability of agroforestry is needed from responsible bodies in Ethiopia.
... A positive and signifcant correlation of soil organic carbon (SOC) of Balanites aegyptiaca-based silvopastoral system among diferent components of parameters during decomposition demonstrated the interacting efects of fauna on functional aspects of soils [59]. According to Bayala et al. [60] and Lorenz and Lal [61], soil organic carbon changes slower than aboveground vegetation but depends on photosynthesis as a source of organic inputs to compensate for ongoing decline by decomposition. ...
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The aim of this study was to examine the decomposition rates of leaf litter, nutrient release patterns, and the relationship between nutrient release from leaf litter and soil nutrients of four specific agroforestry tree species of Balanites aegyptiaca (L.) Delile, Terminalia brownii (Fresen.) J. Léonard, Croton macrostachyus Hochst, and Cordia africana Lam. The study was conducted in the Gamo zone of southern Ethiopia, specifically at three sites, i.e., Lante, Chano, and Shara. For this study, the litterbag techniques was employed, which involved placing dried leaf litter into nylon mesh bags. These nylon mesh bags were then buried in the soil and periodically retrieved to assess the remaining litter mass and its associated nutrients. SPSS version 24 software was used to analysis the collected data. Significant differences in half-life and turnover rates were observed among all tree species (P<0.05). Terminalia brownii exhibited the longest half-life of 21.7 days and the highest turnover rate of 93.9 days, while Balanites aegyptiaca had the shortest half-life and turnover rates at 14 days and 60.6 days, respectively. The release rates of organic carbon from leaf litter of Terminalia brownii, Croton macrostachyus, and Cordia africana showed negative correlations with soil organic carbon, whereas Balanites aegyptiaca displayed a significant positive correlation, with Pearson values of -0.94, -0.397, -0.95, and 0.71, respectively (P<0.05). Additionally, the rates of nutrient release varied among the four tree species across different time intervals. Generally, this research finding indicates that the rate of leaf litter decomposition and nutrient release patterns vary significantly among the four selected agroforestry tree species.
... As such, minimizing soil disturbance prevents its recirculation into the atmosphere -contrary to current forestry practices, such as clear-cut and forced/induced regeneration. Trees introduced into agroforestry, although not to the extent of close-to-nature forests, follow similar pathways to bind carbon, admitting that the rate and effectiveness of the process is a function of species, system composition, and other variables (Lorenz and Lal, 2014). Agroforestry practices have a long-standing history. ...
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Agriculture is the only provider of human food. However, currently demand seems to exceed the limitations of conventional farming practices, as the latter often rely on scarce resources. The focus of agricultural research appears to be shifting towards another approach, namely sustainable farming, which is hoped to pose a solution for the aforementioned issue. Considerable yield and farm resilience are expected from such a practice to withstand and mitigate negative effects of climate change and provide for human well-being. This paper aims to investigate such possibilities focusing on the Carpathian basin’s climate. First, current trends are analyzed, then ecological farming and its challenges are explained in further detail. Finally, agroforestry is introduced as an approach and framework to react to these challenges. As a result, connection points are highlighted which indicate that combining ecological farming with agroforestry could indeed be the basis of a safe and sustainable agriculture.
... Studies have shown that agroforestry systems can sequester significant amounts of carbon in both above-ground biomass and soil, contributing to the reduction of atmospheric CO2 levels. For example, in tropical regions, the integration of trees into agricultural systems has been shown to increase soil organic carbon levels, improving soil fertility and productivity [32]. ...
Article
The diverse applications and benefits of agroforestry, emphasizing its critical role in enhancing soil health and fertility. Agroforestry, the integration of trees, crops, and livestock within the same land management system, presents numerous advantages. These include improved soil structure, enhanced nutrient cycling, and increased carbon sequestration, contributing to overall ecosystem sustainability and resilience against climate change. Agroforestry systems have been shown to improve soil physical properties by enhancing soil structure and porosity, reducing erosion, and increasing water infiltration and retention. These systems boost soil chemical properties through increased organic matter, enhanced nutrient status and cycling, and favorable changes in soil pH and cation exchange capacity. Key findings from various case studies across tropical, temperate, and arid regions demonstrate the multifunctionality of agroforestry systems. For instance, in the Sahel region of Africa, the integration of Faidherbiaalbida significantly improved soil fertility and increased crop yields. In the temperate regions of the United States, alley cropping with black walnut and corn improved soil structure and provided additional income through timber production. In arid regions like the Thar Desert of India, Prosopis-based agroforestry systems enhanced soil organic carbon and nutrient levels, leading to higher crop yields. Despite these benefits, the adoption of agroforestry practices faces significant challenges. Socio-economic barriers, such as the initial investment costs and land tenure insecurity, hinder widespread adoption. Additionally, a lack of knowledge and training among farmers and insufficient policy and institutional support further impede the implementation of agroforestry. Potential negative impacts, such as competition between trees and crops for resources, allelopathic effects, and management complexity, also need to be addressed through careful planning and management. Emerging trends in agroforestry research focus on integrating climate-smart agriculture principles and exploring the multifunctionality of these systems. Innovations such as precision agroforestry, biochar application, and the development of agroforestry-based bioproducts show promise in enhancing system efficiency and sustainability. However, research gaps remain, particularly in understanding the long-term impacts on soil health, the socio-economic benefits, and the integration of modern technologies. Addressing these gaps requires comprehensive, multidisciplinary approaches to fully realize the potential of agroforestry as a sustainable land management strategy.
... Soil organic carbon sequestration occur as a result of increased soil carbon when the rate of carbon input in the soil exceeds the rate at which it is decomposed by the soil organisms (Leifeld and Fuhrer, 2010;Lorenz and Lal, 2014). This involves the incorporation of the plant remains and other organic matter into the soil to build up the soil organic carbon. ...
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Understanding the value of organic agriculture beyond contemporary food sufficiency is crucial in addressing sustainable agriculture and the welfare of the community. Yet, economic analysis of agricultural output usually focuses on crop yield rather than other intangible values related to environmental health, which mainly encompass human health and the environment. The non-marketable value of the ecosystem services in organic agriculture is always higher than in conventional agriculture. When the non-market value is considered during yield assessment, the difference in crop yield between organic and conventional agriculture may be insignificant or even higher for organic. This paper aims to give a gritty overview of the intangible values of organic agriculture in comparison with conventional agriculture to account for other environmental and health benefits associated with organic farming. This is crucial because productive agroecosystems for sustainable development should be able to meet the needs of the present generation without compromising the ability of the future generation to meet their needs. It has been revealed that the application of ecological principles under organic agriculture brings several environmental and socio-economic benefits. Therefore, there is a need to explore some insights into the values of organic agriculture beyond the contemporary food sufficiency which are usually given less attention during economic analysis, for increased understanding and adoption of this kind of farming to harness the associated potentials.
... Soil texture has been hypothesised to be an important variable influencing SOC storage in tropical agroforestry systems, but conclusive evidence is still lacking (Muchane et al. 2020). Hence, knowledge gaps about SOC storage and nutrient cycling in agroforestry systems remain (Lorenz and Lal 2014). ...
Chapter
Agroforestry systems support several ecosystem processes and services and act as refuges for biodiversity. It is crucial to prioritise sustainability when dealing with food and nutrition shortages considering the changes in land use and the increasing uncertainties, variabilities and extreme events caused by climate change. The character of the dominant tree and the decline in tree variety can have significant effects on how well an ecosystem performs, for example, by diminishing agricultural production and altering nutrient cycle. It is commonly acknowledged that nitrogen-fixing plants are essential to agroforestry systems. In this chapter, we look at the interactions between woody plant species, the effects of woody species on soil fertility, and the significance of considering these factors when designing agroforestry systems. By diversifying food sources, enhancing and preserving soil and minimising wind erosion, agroforestry can be a financially viable and environmentally responsible agricultural technique that can also assist smallholder farmers manage the climate-related extremes.
... These fractions are reported to be significantly influenced by land use, due to the type of vegetation and plant litter inputs [43,44]. AGF and, specifically, LF, should better contribute to SOC loss reduction and SOC stabilisation compared to crop field management practices [11]. Despite this, not many studies exist on LF influences on SOC partitioning. ...
Article
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Background: Landscape features (LF—i.e., the natural and semi-natural areas in agricultural landscapes) positively contribute to soil organic carbon (SOC) sequestration and storage among farmlands. LF-related SOC partitioning still needs context-specific investigation to properly address climate change mitigation goals. Not many studies address LF phytocoenoses traits relation with SOC partitioning. Our study investigates SOC partitioning (total organic carbon [TOC]; labile dissolved organic carbon [DOC]; stable recalcitrant organic carbon [ROC]) between arable fields (AGR) and semi-natural/natural components (NAT: herbaceous field margins, young/mature hedgerows, young/mature woods) in a temperate alluvial pedoclimatic context (Po Plain, Northwestern Italy). Methods: We compared topsoil SOC and its fractions (0–20 cm depth) between: AGR-NAT sites; hedgerows (HED)-AGR sites; and different ecological quality degrees (phytocoenoses were classified by Biological Territorial Capacity [BTC] values and Index of Vegetation Naturalness categories [IVN]--). Results: Our results confirmed a significantly different SOC partitioning behaviour between AGR and NAT sites (NAT: +79% TOC; +409% ROC); AGR sites were negatively correlated with ROC. TOC was a robust ROC predictor. HED had significantly higher TOC (+71%) and ROC (+395%) compared to arable fields, with the highest values in mature hedgerows. DOC showed contrasted behaviours. A linear regression model on BTC and IVN (predictors) and TOC and ROC showed significant positive relationships, especially for ROC. Conclusions: Our study confirmed the LF role in long-term SOC storage among farmlands, which should be coupled with AGR management (with prevalent short-term SOC fractions). LF ecological quality was a determining factor in total and long-term SOC. Proper LF management is pivotal to aligning climate change mitigation goals with other ecological benefits.
... In developing countries, social connections have a crucial impact on the exchange of agricultural knowledge 14 . It has been shown to profoundly affect human behaviour and technology adoption 15 . ...
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Carbon sequestration in agricultural soils is crucial in mitigating the adverse effects of global climate change and enhancing soil fertility. Among various crops, tea plantations show significant promise in adopting carbon sequestration practices. Consequently, the Nilgiris district of Tamil Nadu was purposefully selected for the study, involving 120 tea growers chosen using the snowball sampling method. A theoretical framework was developed to assess the factors influencing tea grower's adoption of carbon sequestration practices. Partial least squares-structural equation modelling (PLS-SEM) was employed to analyse the gathered data. The results demonstrated that factors such as 'know-ledge', 'attitude', 'innovativeness', 'perceived benefits' and 'perceived need' had a significant and positive influence on tea grower's adoption of carbon sequestration practices. In contrast, 'social influence' had no significant effect, underscoring the importance of increasing awareness, providing financial incentives, establishing pricing structures, and implementing government policies related to soil carbon sequestration.
... Grasslands are known to help maintain above and belowground biodiversity, filter water and combat erosion [5,6]. Given that up to 30% of the Earth's terrestrial C is stored in grasslands [7], they play a key role in climate regulation; therefore, grassland management strategies have received increasing national and global interest as potential pathways for sequestering C [8][9][10][11]. ...
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Background Grasslands are essential for providing vital resources in the livestock sector and delivering invaluable ecosystem services such as biodiversity and soil carbon (C) sequestration. Despite their critical importance, these ecosystems face escalating threats from human disturbances, human degradation, and climate change, compromising their ability to effectively stock C. Restoring degraded grasslands emerges as a pragmatic and cost-effective approach to tackling climate change. However, the successful implementation of grassland management toward this goal, faces significant challenges. A systematic mapping approach will help to compile a comprehensive global inventory of studies investigating the impact of differing grassland management practices on soil carbon. In addition, the potential for trade-offs with other greenhouse gas emissions further underlines the value of a systematic assessment. This approach aims to identify knowledge clusters (i.e., well-represented subtopics that are amenable to full synthesis) for potential systematic reviews and pinpoint knowledge gaps requiring further primary research efforts, all contributing to a better understanding of the evidence surrounding this topic. Methods Following systematic evidence synthesis standards, we developed the question to address in the systematic map protocol using the PICO framework. We established a preliminary search string by combining search terms for the Population (Grasslands), Intervention (management) and Outcome (soil carbon) categories, as well as with one additional group (Study types—to focus on farm and field experiments). We will conduct a comprehensive literature search of relevant peer-reviewed and grey literature using Web of Science, Scopus, CABI platforms, Google Scholar, and specialised websites (e.g., Agrotrop). Searches will be conducted in the English, Spanish, Portuguese, French, German, and Mongolian languages, as per the linguistic capabilities of the research team. The comprehensiveness of the search will be assessed by comparing the literature collected to a test-list of forty relevant articles. The repeatability of the literature screening process will be ensured by a list of inclusion/exclusion criteria and inter-reviewer consistency statistical tests. Data extraction will be organised into four complementary sections (article information, PICO categories, study characteristics, measurable parameters), on which we will perform queries to produce the tables, figures and evidence maps that will compose the systematic map. The results will identify and describe knowledge gaps and clusters. Supplementary Information The online version contains supplementary material available at 10.1186/s13750-024-00345-2.
... Biochar, which improves the physical and chemical properties of the soil and, consequently, can enhance plant productivity (Farrell et al., 2013), acts as a good nutrient carrier, reserving macro (N, P, K, Ca, etc.) and micro-nutrients (Mg, Zn, etc.) for plants (Wang et al., 2012). With a wide surface area of approximately 500 m 2 g -1 , biochar has been reported to increase the availability of essential nutrients in the soil, such as Ca, Mg, and K, due to its high water retention and cation exchange capacity (Lorenz and Lal, 2014). In a similar study, it was mentioned that the application of biochar, with its high adsorption capacity, reduced sodium uptake and allowed plant nutrient elements such as K, Ca, and Mg present in the soil solution to become more available due to the increase in soil water content (Akhtar et al., 2015). ...
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Studies are being conducted to develop strategies to reduce the adverse effects of salinity stress. In the present study, it was aimed to determine the interactive effects of salinity stress with biochar on plant growth—the physiological and biochemical attributes of forage peas (Pisum sativum ssp. arvense L.). Salt applications were carried out with irrigation water at concentrations of 0, 25, 50, 75, and 100 mM NaCl. The experiment was conducted using a randomized complete block design with three applications [control: 0 (B0), 2.5% biochar (B1), and 5% biochar (B2)], five salt doses [0 (S0), 25 (S1), 50 (S2), 75 (S3), and 100 (S4) mM NaCl], and three replications, arranged in a 3 × 5 factorial arrangement. In the salt-stressed environment, the highest plant height (18.75 cm) and stem diameter (1.71 mm) in forage pea seedlings were obtained with the application of B1. The root fresh (0.59 g/plant) and dry weight (0.36 g/plant) were determined to be the highest in the B1 application, both in non-saline and saline environments. A decrease in plant chlorophyll content in forage pea plants was observed parallel to the increasing salt levels. Specifically, lower H2O2, MDA, and proline content were determined at all salt levels with biochar applications, while in the B0 application these values were recorded at the highest levels. Furthermore, in the study, it was observed that the CAT, POD, and SOD enzyme activities were at their lowest levels at all salt levels with the biochar application, while in the B0 application, these values were determined to be at the highest levels. There was a significant decrease in plant mineral content, excluding Cl and Na, parallel to the increasing salt levels. The findings of the study indicate that biochar amendment can enhance forage peas’ growth by modulating the plant physiology and biochemistry under salt stress. Considering the plant growth parameters, no significant difference was detected between 2.5% and 5% biochar application. Therefore, application of 2.5 biochar may be recommended.
... According to [57], Erosion has been a major loss mechanism for SOC from agro-ecosystems, which accounts for an estimated 20-50% of historic C losses. The increase in SOC content and SOC stock on the tree based land use systems compared with treeless crop lands might also be due to increased biomass input to the soil of the HAF by continuous supply of organic matter [5], extensive root system of the trees in the HAF and recovery of nutrients from below the crop rooting zone [58,59]. While low amount of organic materials added to the soil of the treeless cropland because of complete removal of the biomass from the field and reduced physical protection of SOC may be the reasons for low SOC content and SOC stock in the treeless croplands. ...
Article
Justification: To reverse the challenges of land degradation, improve soil fertility and access to feed and wood, communities in the lowlands of northern Ethiopia started to establish homegarden agroforestry (HAF) decades ago. However, limited information is available and there was information gap on the effects of homegarden agroforestry systems (HAF) on soil properties and soil organic carbon stock enhancement in the Tigray lowlands, Northern Ethiopia. Aim: The objective of this was to explore the effect of conversion of mono-cropping systems (MCS) to HAF in Tselemti district, Tigray lowland, Northern Ethiopia. Materials, Methods and Statistical Methods Used: Two land use types, HAF and MCS fields replicated 15 times were considered. Thus, 30 fields, 15 from HAF & 15 from MCS were used. From each field, 1 composite soil sample for analysis of soil nutrients and 1 undisturbed soil sample for soil bulk density (BD) determination were collected from a depth of 0-30cm. All values were subjected to SPSS version 20 and analyzed using paired samples t-Test statistics at 5% level of significance. Results: The intervention of HAF resulted in significantly higher (p<0.05) and enhance SOC by 76% (1.66 +0.06 and 0.94 + 0.05 %); SOC stock by 82% (73+ 3 and 40+2); N by 75% (0.14 +0.02 and 0.08 + 0.01 %);avP by 37% (6.07 +0.58 and 4.42 + 0.21 ppm) and K by 26% (67.05+ 4.5 and 53.39+ 4.3 mg kg-1) (p<0.05) as compared to the MCS. Conclusion: This study elucidated that home gardening can help for maintaining soil nutrients and soil organic carbon stock. Hence, additional HAF have to be established in the area and in areas with similar bio-physical and socio-economic set up and the government should establish programs and campaigns to disseminate HAF systems and promote the importance of the land use.
... Spatial heterogeneity can intensify over time. Although mean values for soil organic carbon tend to respond slowly to changes in land use, variations in quantity and quality of plant inputs, light, temperature, soil characteristics and soil moisture regimes can give rise to different rates in carbon sequestration (Lorenz and Lal 2014) and this could cause spatial variation over short ranges (less than 50 m). Rates of organic matter decomposition can also affect pH and available phosphorous. ...
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Cacao can be cultivated either as a monoculture or within diverse agroforestry systems, which differ, among others, in the choice of shade tree species, tree density, and whether conventional or organic management is applied. Agroforestry can improve ecosystem services in comparison to cacao monocultures, but the effect of different systems on soil quality, a main driver of the whole ecosystem´s health, needs further investigation. We analysed soil samples from a long-term trial in Bolivia that compares conventional and organic monocultures, conventional and organic agroforestry, successional agroforestry, and fallow plots. We measured chemical parameters (pH, organic carbon, available phosphorous), microbial parameters (microbial biomass carbon and phosphorous, microbial activity), and enzymatic activity (phosphatase, β-glucosidase, urease and protease activities). Plant inputs to soil were also quantified in the different systems. Soil organic matter and enzymatic activities were higher in fallow plots than in monocultures. Agroforestry showed intermediate values, not significantly higher than monocultures. Management type (organic versus conventional) had minimal impact on most parameters. Plant matter input quantity did not affect soil properties, suggesting that quality and diversity of plant inputs might have stronger effects than the quantity. Moderate to strong spatial variability was observed for all studied parameters. For microbial and biochemical properties, sampling season also caused strong variation. Our study contributes to highlighting that the characteristics of specific plants, such as those that grow in the fallow plots, could have a higher impact on soil quality than the sheer quantity of fresh plant material incorporated into the soil.
... Trees can reduce wind speeds over crops, reducing transpiration and drought stress [35,39]. Trees in agriculture aid in regenerating and retaining soil carbon [40], improve biodiversity [18,50], and provide other ecosystem services related to air, water, and carbon [33]. However, trees also compete with crops for space, light, water, and nutrients [47,56], and are often cleared from agricultural areas, although tree management and arrangement can mitigate competition and trade-offs between trees and crop production. ...
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Background Integrating trees into agricultural landscapes can provide climate mitigation and improves soil fertility, biodiversity habitat, water quality, water flow, and human health, but these benefits must be achieved without reducing agriculture yields. Prior estimates of carbon dioxide (CO2) removal potential from increasing tree cover in agriculture assumed a moderate level of woody biomass can be integrated without reducing agricultural production. Instead, we used a Delphi expert elicitation to estimate maximum tree covers for 53 regional cropping and grazing system categories while safeguarding agricultural yields. Comparing these values to baselines and applying spatially explicit tree carbon accumulation rates, we develop global maps of the additional CO2 removal potential of Tree Cover in Agriculture. We present here the first global spatially explicit datasets calibrated to regional grazing and croplands, estimating opportunities to increase tree cover without reducing yields, therefore avoiding a major cost barrier to restoration: the opportunity cost of CO2 removal at the expense of agriculture yields. Results The global estimated maximum technical CO2 removal potential is split between croplands (1.86 PgCO2 yr− 1) and grazing lands (1.45 PgCO2 yr− 1), with large variances. Tropical/subtropical biomes account for 54% of cropland (2.82 MgCO2 ha− 1 yr− 1, SD = 0.45) and 73% of grazing land potential (1.54 MgCO2 ha− 1 yr− 1, SD = 0.47). Potentials seem to be driven by two characteristics: the opportunity for increase in tree cover and bioclimatic factors affecting CO2 removal rates. Conclusions We find that increasing tree cover in 2.6 billion hectares of agricultural landscapes may remove up to 3.3 billion tons of CO2 per year – more than the global annual emissions from cars. These Natural Climate Solutions could achieve the Bonn Challenge and add 793 million trees to agricultural landscapes. This is significant for global climate mitigation efforts because it represents a large, relatively inexpensive, additional CO2 removal opportunity that works within agricultural landscapes and has low economic and social barriers to rapid global scaling. There is an urgent need for policy and incentive systems to encourage the adoption of these practices.
... The accumulation of litter from leaf and twig shedding from N-fixing trees acts as the primary source of nutrients and organic C in agroforestry systems. Furthermore, the increase in microbial diversity facilitated by organic matter contributes to efficient nutrient cycling, including mycorrhizal activities that release P and enhance nutrient uptake by crops (Lacombe et al., 2009;Lorenz and Lal, 2014). Prior studies by Tsufac et al. (2021) in the southwest region of Cameroon, Nath et al. (2015) in bamboo-based agroforestry in northeast India, and Riyadh et al. (2018) in jackfruit-based agroforestry in central Bangladesh have reported improvement in soil fertility due to adoption of agroforestry systems. ...
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Traditionally, planting trees on agricultural land including livestock is a very common practice in the mid-hills of Nepal. Trees on farms fulfill the demand for fuel wood/timber including fodder used to feed the livestock. Animal urine/dung is used as a bio-fertilizer that increases soil fertility. However, very few studies have been conducted on assessing carbon (C) stock and soil quality in agroforestry systems. This study was carried out to estimate the C stock and soil quality in agroforestry and agricultural land in the Kaski district of Nepal. Silvo-horto-agro system and agricultural land were selected from Site 1 (900–1000 m and west) and Site 2 (700–800 m and west). Total C stock was higher in the agroforestry at Site 1 (98.57 t ha 1 ) than agroforestry at Site 2 (64.73 t ha 1 ). Soil organic C, pH, and available potassium were higher in agroforestry than agriculture sites. Total ni trogen was higher in agroforestry than agriculture at Site 1. Available phosphorus was higher in agriculture than agroforestry at Site 1. Soil quality index (SQI) was good (0.8) and fair (0.6) in agroforestry and agriculture at Site 1. SQI was fair (0.6) in agroforestry and poor (0.5) in agriculture at Site 2. Altogether, the application of farmyard manure and vermi-compost including the higher vegetation density contributes to enhancing the soil quality in agroforestry systems. Further research on C stock including various soil quality indices is necessary under various kinds of agroforestry systems for a better understanding of their contribution towards climate change mitigation.
... This biomass, generated by plants, eventually makes its way into the soil, leading to the indirect sequestration of carbon in the form of soil organic carbon during and after the decomposition process (Lal, 2008). The practice of agroforestry, therefore, contributes to climate change mitigation in several ways, including carbon sequestration in the soil through organic matter (Lorenz and Lal, 2014). Carbon sequestration in soils is influenced by various factors, including soil texture, such as clay (Kahle et al., 2003;Konen et al., 2003), silt (Six et al., 2002;Christopher and Lary, 2016;Zhang et al., 2022), and climatic factors, primarily temperature and rainfall (Zhang et al., 2022). ...
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Agroforestry systems, which integrate trees and shrubs with crops and/or livestock, offer a promising approach for sustainable horticulture production. These systems can enhance biodiversity, improve soil health, sequester carbon, diversify income streams for farmers, and boost resilience to climate change. This chapter examines the principles, practices, benefits and challenges of agroforestry systems in the context of horticultural crops. It reviews different agroforestry models such as alley cropping, silvopasture, forest farming, and homegardens, and their suitability for various horticultural species. The chapter also discusses key management considerations such as species selection, spacing, pruning, and nutrient cycling. Case studies from different agroecological regions of India are presented to illustrate the implementation and impacts of agroforestry systems. The chapter concludes with recommendations for scaling up agroforestry for sustainable horticulture production through supportive policies, extension services, market linkages, and research.
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Agroforestry as a planting strategy for restoration, conservation, and climate change mitigation, can alter plant carbon (C) input and microbial-mediated C output, which in turn affects soil organic carbon (SOC) accumulation. However, a quantitative analysis of the C sequestration potential of agroforestry at the global scale is lacking. Here, by collecting 561 pairs of observations worldwide, we conducted a meta-analysis to quantify the impact of agroforestry on SOC sequestration as well as soil properties and microorganisms. On average, agroforestry increased SOC by 10.7 %, dissolved organic carbon by 10.2 % and CO2 emissions by 10.2 % compared to other land uses (cropland, forest and uncultivated land). Across all climate zones, SOC of agroforestry increased the most in arid areas (18.7 %). Compared with monoculture, agroforestry has more advantages in terms of microbial biomass, diversity and soil nutrient content. Our findings highlight the response of agroforestry SOC sequestration to different land managements and climate zones.
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Organic matter is a key component of soil because it influences its structural, chemical, and biological properties, as well as its proper functioning. Although carbon is a crucial component in soil, its elevated levels in the atmosphere since pre-industrial times are warming the Earth relatively. The mechanism of harvesting CO2 from the atmosphere is known as carbon sequestration. Enhanced SOM boosts plant productivity through improved water and nutrient retention in natural and agricultural settings. Soils hold almost three times more carbon than the atmosphere, thus becoming the largest land-based carbon pool. According to the IPCC, croplands and grasslands sequester 0.4–8.6 Gt CO2 year−1. The oceans, on the other hand, are the world’s greatest sink of atmospheric carbon. However, due to the untapped potential of the different ecosystems in order to sequester atmospheric carbon, this chapter tries to understand the dynamism of carbon sequestration among different terrestrial and aquatic ecosystems and highlights some processes and amendments in the soil that can enhance carbon sequestration and discusses its impacts on the regular functioning of ecosystems and its services.
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The sustainable development goals (SDGs) provide a comprehensive framework for addressing global challenges, including land degradation, poverty, climate change, and environmental degradation. Regenerative agriculture (RA) intersects with several SDGs, including zero hunger (Goal 2), climate action (Goal 13), life on land (Goal 15), and responsible consumption and production (Goal 12). It offers a promising pathway to a more equitable and sustainable future by promoting environmental sustainability, enhancing food security, and fostering socio-economic development. Various studies examine its role in meeting the sustainable development goals (SDGs), particularly focusing on its impact on mitigating climate change and conserving terrestrial and marine ecosystems. RA prioritizes soil health, biodiversity, and ecosystem resilience, which in turn, helps mitigate climate impacts and improve food availability. Through systematized regenerative practices, communities can achieve these goals effectively and efficiently. Through case studies from sub-Saharan Africa, South-east Spain, and Western Kenya, RA demonstrates its efficacy in restoring soil health, mitigating erosion, and enhancing water infiltration, thereby contributing to achieving SDGs 14 and 15. Furthermore, it addresses the climate crisis by promoting soil carbon sequestration and reducing greenhouse gas emissions. Practices such as conservation tillage, agroforestry, and integration of forage crops exemplify effective strategies in mitigating climate impacts. RA aligns with SDGs 3, 8, and 17 by addressing contemporary health challenges, fostering economic growth, and promoting global partnerships for sustainable development. RA produces safer food and improves human health by reducing risks associated with soil pollution and chemical residues. Additionally, RA creates employment opportunities, particularly in rural areas, and promotes global partnerships through initiatives like carbon farming. Overall, regenerative agriculture offers a multifaceted approach to food production that improves human health, fosters economic growth, and promotes global sustainability, thus contributing significantly to achieving the United Nations’ Sustainable Development Goals.
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Ecosystems and their associated living organisms are struggling for their survival and existence due to climate change. The atmospheric concentration of greenhouse gasses (GHG) increases considerably, which has now crossed the digit of 397.60 ppm3 and set to rise further. The climate scenario in Pakistan has posing negative impacts due to persistent change in the climate. In the coming years, i.e., 2025 if the present rate of increases continues, the atmospheric concentration of carbon dioxide would be increasing the globe’s temperature up to 2 ºC–4 ºC. Minimizing the concentration of atmospheric carbon and sequestering it into the agricultural landscape (soil, trees, crops) is the most effective, cheaper eco-friendly approach. Agroforestry (AF) is an integral part of climate-smart agriculture that involves the growing of forest trees and raising agricultural crops and livestock on a particular piece of land. Agriculture happens to be the major contributor to the atmospheric concentration of carbon dioxide; however, soil carbon sequestration is the most efficient tool to enrich soil organic carbon pools, which depend on improved agricultural practices. Trees when grown in combination with agricultural crops store more carbon range 34.61 t C ha−1 than the monocrop system with 18.74 t C ha−1. This chapter provides analyzes of the current knowledge about soil organic carbon (SOC) sequestration processes and their management in agroforestry systems. A detailed discussion on the useful C sequestration tree species (E. camaldulensis, S. cumin, P. ciliata, A. Acacia, Z. manritiana, C. sinensis, A. indica, D. sisso, Bambusoideae, M. azedarach, and M. alba) in the agroforestry systems and their role in climate change mitigation, enhancing soil organic carbon sequestration in agroforestry soils and sequestration rates, and the processes contributing to the stabilization of SOC in agroforestry soils has been presented. The analysis led to revealing that climate-smart agriculture has great potential to lockup more carbon and helps in the reduction of CO2 emissions to the atmosphere.
Chapter
Agroforestry is a long-standing tradition, particularly prevalent in Asia and Africa. The rising population burden has led to the imprudent exploitation of natural resources and the destabilisation of the ecosystem. The rise in demand for both forest and non-forest goods has resulted in several environmental issues, including land erosion, flooding, storms, forest degradation, soil fertility decline, natural catastrophes, and seasonal climatic fluctuations. Food security will be significantly affected in the future due to climate change, population growth, increasing food costs, and environmental stresses. However, the exact implications of these factors are unpredictable. More than 800 million individuals globally suffer from nightly hunger, predominantly small-scale farmers who depend on agriculture for their sustenance and familial assistance. Furthermore, there is a pressing need to increase global food production twofold by the year 2050 in order to adequately nourish a population of nine billion individuals. The adverse effects on the global ecology necessitate focused attention, and we must address these requirements with more efficiency. Developing adaptation plans and policy responses to climate change is crucial. These encompass remedies for the distribution of water, patterns of land utilisation, trading of food, processing of food after harvesting, and the assurance of food security and stable pricing. In order to guarantee sufficient food supply, it is beneficial for nations to synchronise immediate assistance with a comprehensive development strategy, enabling them to sustainably provide food for their populations. Agroforestry has the potential to enhance livelihoods by promoting improved health and nutrition, fostering economic growth, bolstering environmental resilience, and ensuring the sustainability of ecosystems. Farm diversification is an increasingly popular approach to enhance economic competitiveness. Agroforestry has promising opportunities for the sustainable cultivation of specialised nut and fruit crops, valuable medicines, as well as dairy and beef cattle, sheep, and goats. In addition, agroforestry systems offer established methods for long-term carbon sequestration, soil enrichment, biodiversity preservation, and enhancement of air and water quality. These benefits are advantageous for both landowners and society as a whole.
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Agroforestry is one of the sustainable approaches to land-use management where both agriculture and forestry combine into an integrated production system to get maximum benefits (Kidd and Pimentel, 1992; Nair, 1998). As per ICRAF (International Centre for Research in Agroforestry, now World Agroforestry Centre), '‘agroforestry is a deliberate integration of woody components with agricultural and pastoral operations on the same piece of land either in a spatial or temporal sequence in such a way that both ecological and economic interactions occur between them.'’ Incorporation of the trees under agroforestry systems (AFS) to harvest potential benefits of trees offers a good option under Low Input Sustainable Agriculture (LISA). In fact, it is an age-old practice revived in the recent past with a renewed scientific interest to maintain the sustainability of agroecosystems (Noble and Dirzo, 1997). The revival of agroforestry became inevitable to meet growing demands of increasing population, to compensate forests in the wake of fast increasing rate of deforestation and soil degradation, both in the tropics and temperate regions of the world, and to conserve biodiversity. Agroforestry provides one of the best alternatives for planting trees outside forests. In other words, it is a collective name for sustainable land-use system to get social, economical, and environmental benefits (Sanchez, 1995). It leads to a more diversified and sustainable system than other croplands without trees. Griffith (2000) considers agroforestry as an alternative subsistence farming patterns for conservation and development, particularly in the tropics. Though practiced in the majority of ecoregions, agroforestry is more common in the tropics. According to a report of the World Bank, around 1.2 billion rural people currently practice agroforestry the world over (World Bank, 2004). There are more than 2000 tree species used in agroforestry (Rao et al., 2000). AFS have been classified based on structural, functional, physiognomy, fioristics, socioeconomic, and ecological aspects (Nair, 1993; Ffolliott, 2003). However, classification based on structural components is very common.
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Conceptual models suggest that stability and age of organic carbon (OC) in soil depends on the source of plant litter, occlusion within aggregates, incorporation in organo-mineral complexes, and location within the soil profile. Various tools like density fractionation, mineralization experiments, and radiocarbon analyses have been used to study the importance of these mechanisms. We systematically apply them to a range of European soils to test whether general controls emerge even for soils that vary in vegetation, soil types, parent material, and land use. At each of the 12 study sites, 10 soil cores were sampled in 10 cm depth intervals to 60 cm depth and subjected to density separation. Bulk soil samples and density fractions (free light fractions – fLF, occluded light fractions – oLF, heavy fractions – HF) were analysed for OC, total nitrogen (TN), δ13C, and Δ14C. Bulk samples were also incubated to determine mineralizable OC. Declining OC-normalized CO2 release and increasing age with soil depth confirm greater stability of OC in subsoils across sites. Depth profiles of LF-OC matched those of roots, which in turn reflect plant functional types in soil profiles not subject to ploughing. Modern Δ14C signatures and positive correlation between mineralizable C and fLF-OC indicate the fLF is an easily available energy and nutrient source for subsurface microbes. Fossil C derived from the geogenic parent material affected the age of OC especially in the LF at three study sites. The overall importance of OC stabilization by binding to minerals was demonstrated by declining OC-normalized CO2 release rates with increasing contributions of HF-OC to bulk soil OC and the low Δ14C values of HF-OC. The stability of HF-OC was greater in subsoils than in topsoils; nevertheless, a portion of HF-OC was active throughout the profile. The decrease in Δ14C (increase in age) of HF-OC with soil depth was related to soil pH as well as to dissolved OC fluxes. This indicates that dissolved OC translocation contributes to the formation of subsoil HF-OC and shapes the Δ14C profiles. While quantitatively less important than OC in the HF, consistent older ages of oLF-OC than fLF-OC indicate that occlusion of LF-OC in aggregates also contributes to OC stability in subsoils. Overall, our results showed that association with minerals is the most important factor in stabilization of OC in soils.
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In early 1992, a silvoarable experiment, comprising four poplar (Populus spp.) hybrids (at a spacing of 10 m x 6.4 m) and four arable treatments, was established at three contrasting lowland sites in England. By the end of 1998, seven years after planting, the height of the poplar hybrid Beaupré (11.9 m) was greater than those of the hybrids Gibecq, Robusta and Trichobel (8.9-9.8 m). The trees at the most exposed site had the shortest height (9.2 m) and the greatest diameter at breast height (173 mm). Tree growth was also affected by the arable treatments. The height (9.5 m) and diameter (143 mm) of the trees bordered on both sides by a continuous rotation of arable crops were 89% and 79%, respectively, of those bordered on both sides by a regularly cultivated fallow. This result could be explained by competition for water. Across the three sites, in the presence of the trees the yield per unit cropped area, relative to that in the control areas, was an average of 4% less in the first three years and an average of 10% less between years four and six. However the specific responses were dependent on the arable crop. The experiment also included an alternately-cropped arable treatment, where the crop was alternated with a one-year bare fallow. The benefits of a preceding fallow, rather than a cereal crop, for yield were greatest for wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) and least for field beans (Vicia faba L.),peas(Pisum sativum L.) and mustard (Brassica alba L.).
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In response to the declining soil fertility in southern Africa and the negative effects that this leads to, such as food insecurity besides other developmental challenges, fertilizer tree systems (FTS) were developed as technological innovation to help smallholder farmers to build soil organic matter and fertility in a sustainable manner. In this paper, we trace the historical background and highlight the developmental phases and outcomes of the technology. The synthesis shows that FTS are inexpensive technologies that significantly raise crop yields, reduce food insecurity and enhance environmental services and resilience of agro-ecologies. Many of the achievements recorded with FTS can be traced to some key factors: the availability of a suite of technological options that are appropriate in a range of different household and ecological circumstances, partnership between multiple institutions and disciplines in the development of the technology, active encouragement of farmer innovations in the adaptation process and proactive engagement of several consortia of partner institutions to scale up the technology in farming communities. It is recommended that smallholder farmers would benefit if rural development planners emphasize the merits of different fertility replenishment approaches and taking advantage of the synergy between FTS and mineral fertilizers rather than focusing on 'organic vs. inorganic' debates.
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Despite widespread use in the literature, there seems to be little consensus on what the term ‘carbon (C) sequestration’ means. We differentiate between endogenous C, which fluxes within a system, and exogenous C, which fluxes between systems. Here we define ‘endogenous C sequestration’ as occurring when C fixation to release ratio is greater than one (fixation(a,s)/release(a,s) >1), expressed at the briefest, annually (a) and budgeted within a specified system (s). We distinguish between sequestered C (stored for >1 year) and temporarily utilized biologic C (i.e., labile C present within a living organism), developing equations for herbaceous and woody plant systems. Standardized expression of C sequestration with incorporation of descriptors, for example ‘somatic C sequestration(10 year, forest)’, clarifies the location, timescale and system being considered and should allow for increased transparency and improved communication for climate change debates and C budgeting.
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This book provides a synthesis of plant-soil-plant interactions from the plot to landscape scale. It focuses on the process level, which is relevant to many types of multispecies agroecosystems (agroforestry, intercropping and others). It also links basic research to practical application (and indigenous knowledge) in a wide range of systems with or without trees, and considers implications of below-ground interactions for the environment and global change issues. The contents include root architecture and dynamics, plant-soil biota interactions, soil biodiversity and food webs, water and nutrient cycling, and the necessary linkage to modelling approaches.
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Climate change adaptation and mitigation are usually the objects of separate projects, but in this review we argue that in agricultural contexts, there are often technical and financial advantages in pursuing them simultaneously. This is because (1) adaptation planning is often necessary for mitigation (i.e., carbon sequestration) planning, especially for assessing future climate risks to mitigation investments, (2) certain land-use interventions can have both adaptation and mitigation benefits, and (3) carbon finance can help in supporting adaptation which still tends to be underfunded. Agroforestry and ecosystem conservation are key approaches in the integration of climate change adaptation and mitigation objectives, often generating significant co-benefits for local ecosystems and biodiversity. Synergies between climate change adaptation and mitigation actions are particularly likely in projects involving income diversification with tree and forest products, reduction of the susceptibility of land-use systems to extreme weather events, improvement of soil fertility, fire management, wind breaks, and the conservation and restoration of forest and riparian corridors, wetlands, and mangroves. On the other hand, trade-offs between adaptation and mitigation are possible when fast-growing tree monocultures for mitigation conflict with local tree and forest uses, making livelihoods more vulnerable, when trees are planted in water-scarce areas conflicting with local water uses, and in some cases when “climate-smart” agroforestry practices conflict with the need for agricultural intensification to produce increasing amounts of food for a growing population. Such conflicts need to be avoided through careful, site-specific, and participatory project development. We conclude that adaptation considerations should be included in mitigation project planning and integrated adaptation and mitigation activities should be prioritized in carbon markets and policy formation.
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The perception that agroforestry systems have higher potential to sequester carbon than comparable single-species crop systems or pasture systems is based on solid scientific foundation. However, the estimates of carbon stock of agroforestry systems in Africa — reported to range from 1.0 to 18.0 Mg C ha−1 in aboveground biomass and up to 200 Mg C ha−1 in soils, and their C sequestration potential from 0.4 to 3.5 Mg C ha−1 yr−1–are based on generalizations and vague or faulty assumptions and therefore are of poor scientific value. Although agroforestry initiatives are promising pathways for climate-change mitigation, rigorous scientific procedures of carbon sequestration estimations are needed for realizing their full potential.
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Depletion of ecosystem carbon stocks is a significant source of atmospheric CO2 and reducing land-based emissions and maintaining land carbon stocks contributes to climate change mitigation. We summarize current understanding about human perturbation of the global carbon cycle, examine three scientific issues and consider implications for the interpretation of international climate change policy decisions, concluding that considering carbon storage on land as a means to 'offset' CO2 emissions from burning fossil fuels (an idea with wide currency) is scientifically flawed. The capacity of terrestrial ecosystems to store carbon is finite and the current sequestration potential primarily reflects depletion due to past land use. Avoiding emissions from land carbon stocks and refilling depleted stocks reduces atmospheric CO2 concentration, but the maximum amount of this reduction is equivalent to only a small fraction of potential fossil fuel emissions.
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Expansion of agricultural land use has increased emission of greenhouse gases, exacerbating climatic changes. Most agricultural soils have lost a large portion of their antecedent soil organic carbon storage, becoming a source of atmospheric carbon-dioxide. In addition, agricultural soils can also be a major source of nitrous oxide and methane. Adoption of conservation agricultural practices may mitigate some of the adverse impacts of landuse intensification. However, optimal implementation of these practices is not feasible under all physical and biotic conditions. Of a wide range of conservation practices, the most promising options include agroforestry systems and soil application of biochar, which can efficiently sequester large amounts of carbon over the long-run. In addition, these practices also increase agronomic productivity and support a range of ecosystem services. Payments to farmers and land managers for sequestrating carbon and improving ecosystem services is an important strategy for promoting the adoption of such practices, aimed at mitigating climate change while decreasing environmental footprint of agriculture and sustaining food security.
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Agroforestry is one of the most conspicuous land use systems across landscapes and agroecological zones in Africa. With food shortages and increased threats of climate change, interest in agroforestry is gathering for its potential to address various on-farm adaptation needs, and fulfill many roles in AFOLU-related mitigation pathways. Agroforestry provides assets and income from carbon, wood energy, improved soil fertility and enhancement of local climate conditions; it provides ecosystem services and reduces human impacts on natural forests. Most of these benefits have direct benefits for local adaptation while contributing to global efforts to control atmospheric greenhouse gas concentrations. This paper presents recent findings on how agroforestry as a sustainable practice helps to achieve both mitigation and adaptation objectives while remaining relevant to the livelihoods of the poor smallholder farmers in Africa.
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Silvopasture systems combine trees, forage, and livestock in a variety of different species and management regimes, depending on the biophysical, economic, cultural, and market factors in a region. We describe and compare actual farm practices and current research trials of silvopastoral systems in eight regions within seven countries of the world: Misiones and Corrientes provinces, Argentina; La Pampa province, Argentina; northwestern Minas Gerais, Brazil; the Aysén region of Patagonia, Chile; the North Island of New Zealand; the Southeast United States; Paraguay; and Uruguay. Some countries use native trees and existing forests; some use plantations, particularly of exotic species. Natural forest silvopasture systems generally add livestock in extensive systems, to capture the benefits of shade, forage, and income diversification without much added inputs. Plantation forest systems are more purposive and intensive, with more focus on joint production and profits, for small owners, large ranches, and timber companies. Trends suggest that more active management of both natural and planted silvopastoral systems will be required to enhance joint production of timber and livestock, achieve income diversification and reduce financial risk, make more profit, improve environmental benefits, and realize more resilience to adapt to climate change.
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Ever since the Kyoto Protocol, agroforestry has gained increased attention as a strategy to sequester carbon (C) and mitigate global climate change. Agroforestry has been recognized as having the greatest potential for C sequestration of all the land uses analyzed in the Land-Use, Land-Use Change and Forestry report of the IPCC; however, our understanding of C sequestration in specific agroforestry practices from around the world is rudimentary at best. Similarly, while agroforestry is well recognized as a land use practice capable of producing biomass for biopower and biofuels, very little information is available on this topic. This thematic issue is an attempt to bring together a collection of articles on C sequestration and biomass for energy, two topics that are inextricably interlinked and of great importance to the agroforestry community the world over. These papers not only address the aboveground C sequestration, but also the belowground C and the role of decomposition and nutrient cycling in determining the size of soil C pool using specific case studies. In addition to providing allometric methods for quantifying biomass production, the biological and economic realities of producing biomass in agroforestry practices are also discussed.
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Afforestation is known as an available mitigation activity to climate change because it causes sequestration of CO2 from the atmosphere and stores it as the living biomass and the dead organic matter. However, the response of soil organic carbon (SOC) to afforestation in deep soil layers is still poorly understood. We surveyed previously published literature for changes in deep SOC (defined as at least 10 cm deeper than the 0–10 cm layer) after afforestation of croplands and grasslands (total 63 sites from 56 literature), in order to examine changes in deep SOC and quantify the relationship between SOC change rates in topsoil and subsoil. The results of the meta analysis indicated that the responses of SOC to afforestation were opposite for cropland than grassland. The SOC in soil depth layers of 0–10, 10–20, 20–40, 40–60 and 60–80 cm were reduced with afforestation of grassland but not significantly (p > 0.05), while conversion of cropland to forests (trees or shrubs) increased SOC significantly for each soil depth layer up to 60 cm depth (p < 0.05). Significant relationships of SOC change rate were found between topsoil (0–20 cm) and deeper soil layers (20–40 and 40–60 cm). The linear regression showed that SOC change rate in 0–40 cm, 0–60 cm, and 0–100 cm soil profiles was 1.33, 1.49, and 1.55 times greater, respectively than the change rates in the corresponding 0–20 cm depth profile. Partial correlation analysis revealed that stand age and initial SOC content were determinants of deep soil SOC change after afforestation of agricultural soils. This study also showed that the O horizon can play an important role in carbon sequestration after afforestation of agricultural sites. We concluded that subsoil carbon must be taken into account when evaluating of SOC change with afforestation and, therefore, recommended that the soil sampling depth for afforested soils be set to at least 60 cm in mineral soils and include the O horizon. However, due to poor study designs and lack of standardized sampling protocols in the literature, these results were high in uncertainty.
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The latest carbon dioxide emissions continue to track the high end of emission scenarios, making it even less likely global warming will stay below 2 °C. A shift to a 2 °C pathway requires immediate significant and sustained global mitigation, with a probable reliance on net negative emissions in the longer term.
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A considerable amount of data is available about above-ground biomass production and turnover in tropical agroforestry systems, but quantitative information concerning root turnover is lacking. Above- and below-ground biomass dynamics were studied during one year in an alley cropping system withGliricidia sepium and a sole cropping system, on aPlinthic Lixisol in the semi-deciduous rainforest zone of the Côte d'Ivoire. Field crops were maize and groundnut. Live root mass was higher in agroforestry than in sole cropping during most of the study period. This was partly due to increased crop and weed root development and partly to the presence of the hedgerow roots. Fine root production was higher in the alleys and lower under the hedgerows compared to the sole cropping plots. Considering the whole plot area, root production in agroforestry and sole cropping systems was approximatly similar with 1000–1100 kg ha–1 (dry matter with 45% C) in 0–50 cm depth; about 55% of this root production occured in the top 10 cm. Potential sources of error of the calculation method are discussed on the basis of the compartment flow model. Above-ground biomass production was 11.1 Mg ha–1 in sole cropping and 13.6 Mg ha–1 in alley cropping, of which 4.3 Mg ha–1 were hedgerow prunings. The input of hedgerow root biomass into the soil was limited by the low root mass ofGliricidia as compared to other tree species, and by the decrease of live root mass of hedgerows and associated perennial weeds during the cropping season, presumably as a result of frequent shoot pruning.
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