Unlocking climate resilience by exploring the mitigation potential of improved rotation with cover cropping.

Soil organic carbon (SOC) sequestration in agricultural soils is an important tool for climate change mitigation within the EU soil strategy for 2030 and can be achieved via the adoption of soil management strategies (SMS). These strategies may induce synergistic effects by simultaneously reducing greenhouse gas (GHG) emissions and/or nitrogen (N) leaching. In contrast, other SMS may stimulate emissions of GHG such as nitrous oxide (N 2 O) or methane (CH 4 ), offsetting the climate change mitigation gained via SOC sequestration. Despite the importance of understanding trade‐offs and synergies for selecting sustainable SMS for European agriculture, knowledge on these effects remains limited. This review synthesizes existing knowledge, identifies knowledge gaps and provides research recommendations on trade‐offs and synergies between SOC sequestration or SOC accrual, non‐CO 2 GHG emissions and N leaching related to selected SMS. We investigated 87 peer‐reviewed articles that address SMS and categorized them under tillage management, cropping systems, water management and fertilization and organic matter (OM) inputs. SMS, such as conservation tillage, adapted crop rotations, adapted water management, OM inputs by cover crops (CC), organic amendments (OA) and biochar, contribute to increase SOC stocks and reduce N leaching. Adoption of leguminous CC or specific cropping systems and adapted water management tend to create trade‐offs by stimulating N 2 O emissions, while specific cropping systems or application of biochar can mitigate N 2 O emissions. The effect of crop residues on N 2 O emissions depends strongly on their C/N ratio. Organic agriculture and agroforestry clearly mitigate CH 4 emissions but the impact of other SMS requires additional study. More experimental research is needed to study the impact of both the pedoclimatic conditions and the long‐term dynamics of trade‐offs and synergies. Researchers should simultaneously assess the impact of (multiple) agricultural SMS on SOC stocks, GHG emissions and N leaching. This review provides guidance to policymakers as well as a framework to design field experiments and model simulations, which can address knowledge gaps and non‐intentional effects of applying agricultural SMS meant to increase SOC sequestration.

Soil organic carbon sequestration potential of conservation agriculture in arid and semi-arid regions: A review

Legume cover crops enhance soil organic carbon via microbial necromass in orchard alleyways

Abstract:Revegetation is vital for enhancing soil carbon sequestration. However, the impacts of revegetation and terracing measures on soil organic carbon (SOC) and SOC sequestration (SOCS), and the differences in the effects of revegetation on SOC and SOCS when implemented on sloped fields versus terraced fields, are still unclear. Thus, we conducted a field survey on cropland (CL), grassland (GL), and forestland (FL) on both sloped fields and terraced fields in Wuqi county, China’s Loess Plateau. The results showed that SOC content in FL at 0–10 cm, 10–20 cm, 20–40 cm, 40–60 cm depths were 1.70, 1.28, 1.28, and 1.19 times respectively higher than in CL. Similarly, SOC content in GL at the same depths were 1.30, 1.13, 1.18, and 1.20 times higher than in CL. In terraced, SOC content at 40–60 cm, 60–80 cm, 80–100 cm depths were 1.22, 1.28, and 1.20 times respectively higher than on sloped fields. Revegetation primarily significantly affected SOC at 0–10 cm depth on sloped fields (GL: p = 0.04; FL: p < 0.01), and more deeply (0–100 cm) on terraced fields (GL at 40–80 cm: p < 0.05; FL: p < 0.01). Furthermore, revegetation on sloped fields generated the highest SOCS at 0–40 cm depth, with a subsequent decrease as depth increased to 40–100 cm depth. Conversely, on terraced, SOCS increased with soil depth within the 0–100 cm depth. These results indicated that revegetation primarily enhanced SOCS in the surface soil (0–40 cm), and terracing measures stabilized the SOCS in the surface soil and further enhanced them in deeper soil horizons (0–100 cm). Therefore, in the context of soil erosion control and ecological restoration, the combined implementation of vegetation restoration and engineering measures can effectively stabilize and enhance SOCS, thereby fully leveraging the role of soil in mitigation climate change.Keywords: Soil and water conservation measures; Carbon sequestration; Land use change；Vegetation restoration; Engineering measures; Deep soil organic carbon

Interactive impacts of climate change and agricultural management on soil organic carbon sequestration potential of cropland in China over the coming decades

<p>Carbon sequestration in agricultural soils is an important strategy to mitigate climate change which gained renewed attention in the EU soil strategy for 2030. Stimulation of soil organic carbon (SOC) sequestration can be achieved via soil management strategies. However, these strategies may stimulate greenhouse gas (GHG) emissions such as nitrous oxide (N<sub>2</sub>O) and methane (CH<sub>4</sub>) and cause nitrogen (N) losses via leaching. While these trade-offs can offset the intended climate change mitigation via SOC sequestration, synergistic (positive) effects of certain soil management strategies may positively affect the mitigation potential as well. Despite the major importance of these trade-offs and synergies for the selection of sustainable and climate-proof soil management strategies, knowledge on the understanding of these effects remains limited.</p><p>In the Framework of Horizon 2020 – European Joint Programme SOIL, the ∑OMMIT-project aims to investigate the trade-offs and synergies for the most relevant soil management strategies applied in European agricultural systems. A dedicated literature study was made by eight agricultural research institutes across Europe, summarizing the results of reviews, meta-analyses, reports and original articles. The most important soil management strategies were identified and grouped into four categories: tillage management, cropping systems, water management, and fertilization and organic matter (OM) inputs (crop residues, cover crop, livestock manure, slurry, compost, biochar, liming). Search criteria including literature and land use type, time-period, and geographic origin resulted in a unique selection of 110 references (31 reviews, 46 meta-analyses, and 33 original papers). Meta-data, extracted knowledge gaps, research recommendations and main conclusions were compiled in a knowledge gap review which allows for better insight in existing trade-offs and synergies and provides guidance to future research.</p><p>This review highlights that the increase of both SOC stock change and the microbial biomass C and N, as well as the reduction in N leaching are positively affected by conservation tillage, crop rotation, permanent cropping, more efficient water management as well as using fertilization and OM inputs (e.g., cover crops, organic amendments, biochar, and liming). The effects on the N<sub>2</sub>O and CH<sub>4</sub> emission mitigation are dependent on the specific soil management strategy (e.g., water management, fertilization and OM inputs) and require more research to allow to define (uniform) conclusions.</p><p>In conclusion, more dedicated research is needed for the soil management strategies that simultaneously examines SOC stocks, GHG emissions, and N leaching losses. Furthermore, we identified a lack of information on the impact of pedoclimatic conditions, specifically on the longer-term, on trade-offs and synergies. A more concerted use and installation of new long-term field experiments in different pedo-climatic European regions, seems essential for a comprehensive understanding of the impact of soil management strategies at the European level. Further, since soil management strategies are often combined and their interaction may affect the trade-offs and synergies, the impact of different soil management practices should be assessed simultaneously. Overall, the review provides a unique framework to aid the (re)design of dedicated field experiments and targeted measurements as well as simulations to improve our understanding of the identified knowledge gaps.</p>

Modeling soil organic matter changes under crop diversification strategies and climate change scenarios in the Brazilian Cerrado

Agricultural conservation practices (e.g. conservation tillage, cover crops) are critical measures to mitigate nutrient loss and greenhouse gas emissions, enhance soil organic carbon (SOC), and maintain crop yield. Despite these benefits, recent studies indicate that switching to conservation tillage (e.g. no-till) can inadvertently increase nitrate leaching, thereby degrading water quality.  This study presents a meta-analysis of field experiments to elucidate the conflicting outcomes of conservation tillage—increasing SOC levels but simultaneously exacerbating nitrate loss. For instance, SOC in the top 30 cm of soil under no-till (NT) was 14.2% and 4.7% higher than under high-intensity tillage (HT) and intermediate-intensity tillage (IT), respectively. In contrast, nitrate leaching under NT exceeded that under HT and IT by 4.9% and 0.6%, respectively.By leveraging high-resolution datasets of soil characteristics, weather, water quality, land use, and topography, we utilized a comprehensive watershed model, the Terrestrial-Aquatic Sciences Convergence (TASC) to evaluate the combined effects of tillage and cover crops (e.g., winter wheat, rye, and oats) on SOC sequestration, nitrate loading, and crop yield in the Upper Mississippi River Basin (492,000km2). We found that conservation tillage  and cover crops could complement each other. The combined adoption significantly affects water availability, nitrate leaching, SOC, and crop yield. While the integration of cover crops enhances biomass production and SOC, their ability to absorb soil inorganic nitrogen during the non-growing season helps mitigate nitrate leaching. Notably, crop yield under scenarios combining tillage and cover crops surpasses those involving only tillage. However, cover crops can also enhance evapotranspiration, which could potentially aggravate the water availability issues for crop production under future climate conditions. These results underscore the critical need for careful evaluation of the trade-offs between conservation tillage and cover crops when developing policies to address environmental challenges in agricultural ecosystems over the coming decades.

Climate-smart agriculture (CSA) management practices (e.g., conservation tillage, cover crops, and biochar applications) have been widely adopted to enhance soil organic carbon (SOC) sequestration and to reduce greenhouse gas emissions while ensuring crop productivity. However, current measurements regarding the influences of CSA management practices on SOC sequestration diverge widely, making it difficult to derive conclusions about individual and combined CSA management effects and bringing large uncertainties in quantifying the potential of the agricultural sector to mitigate climate change. We conducted a meta-analysis of 3,049 paired measurements from 417 peer-reviewed articles to examine the effects of three common CSA management practices on SOC sequestration as well as the environmental controlling factors. We found that, on average, biochar applications represented the most effective approach for increasing SOC content (39%), followed by cover crops (6%) and conservation tillage (5%). Further analysis suggested that the effects of CSA management practices were more pronounced in areas with relatively warmer climates or lower nitrogen fertilizer inputs. Our meta-analysis demonstrated that, through adopting CSA practices, cropland could be an improved carbon sink. We also highlight the importance of considering local environmental factors (e.g., climate and soil conditions and their combination with other management practices) in identifying appropriate CSA practices for mitigating greenhouse gas emissions while ensuring crop productivity.

No-tillage with rye cover crop can reduce net global warming potential and yield-scaled global warming potential in the long-term organic soybean field

The role of soil organic carbon (SOC) sequestration as a 'win-win' solution to both climate change and food insecurity receives an increasing promotion. The opportunity may be too good to be missed! Yet the tremendous complexity of the two issues at stake calls for a detailed and nuanced examination of any potential solution, no matter how appealing. Here, we critically re-examine the benefits of global SOC sequestration strategies on both climate change mitigation and food production. While estimated contributions of SOC sequestration to climate change vary, almost none take SOC saturation into account. Here, we show that including saturation in estimations decreases any potential contribution of SOC sequestration to climate change mitigation by 53%-81% towards 2100. In addition, reviewing more than 21 meta-analyses, we found that observed yield effects of increasing SOC are inconsistent, ranging from negative to neutral to positive. We find that the promise of a win-win outcome is confirmed only when specific land management practices are applied under specific conditions. Therefore, we argue that the existing knowledge base does not justify the current trend to set global agendas focusing first and foremost on SOC sequestration. Away from climate-smart soils, we need a shift towards soil-smart agriculture, adaptative and adapted to each local context, and where multiple soil functions are quantified concurrently. Only such comprehensive assessments will allow synergies for land sustainability to be maximised and agronomic requirements for food security to be fulfilled. This implies moving away from global targets for SOC in agricultural soils. SOC sequestration may occur along this pathway and contribute to climate change mitigation and should be regarded as a co-benefit.

A 12-year cover crops study on the effects on SOC sequestration, storage, retention and loss and corn and soybean yields was conducted in southern Illinois. The use of cover crops for the maintenance and restoration of soil organic carbon (SOC) and soil productivity of previously eroded soils were evaluated. No-till (NT), chisel plow (CP), and moldboard plow (MP) treatment plots with and without cover crops were established in 2001. The plot area was on sloping with a moderately well drained, eroded soil. The average annual corn and soybean yields were statistically the same for NT, CP, and MP systems with and without cover crops. By 2012, the cover crop treatments had more SOC stock than that without cover crops for the same soil layer and tillage treatment. The NT, CP, and MP treatments all sequestered SOC with cover crops. A pre-treatment SOC stock baseline for rooting zone was used to validate the finding that cover crops sequestered SOC in the topsoil, subsoil and root zone of the NT, CP and MP treatments during the 12-year study. Additional sequestered SOC was lost as a result of being transported off of the plots and retained in lower slopes, transported to the stream or released to atmosphere.

Soil organic carbon (SOC) sequestration is a key nature-based solution to mitigate climate change. Previous studies have highlighted its potential and the role of improve management practice, but many relied on static land-use assumptions or limited spatial data, overlooking socio-economic and climate-driven changes that affect land availability. This study assessed the global SOC sequestration potential of cropland and bioenergy land under three land-use pathways: business as-usual (BAU), a sustainable food system (FOOD), and a 2 °C climate target (2°). Our results show that both climate and food policies may influence SOC sequestration through land-use changes. Under the 2 °C scenario, large-scale expansion of bioenergy crops could increase SOC stocks by about 7% (∼9 Gt CO2). In contrast, the FOOD scenario achieves only modest SOC gains, slightly lower than BAU (−1.59 Gt CO₂). This because dietary shifts reduce pasture demand but do not significantly change cropland area, and bioenergy deployment is limited. While plant-based diets improve food system efficiency and reduce emissions, their SOC benefits are indirect and depend on how freed-up land is used for mitigation, such as afforestation or bioenergy production. Regions with significant bioenergy expansion—such as Latin America, reforming economies, and OECD/EU countries—show the highest SOC gains. Regions with large cropland areas, including the Middle East, Africa, and Asia, contribute 70% of the global potential. Moreover substantial SOC potential can be realized at a cost below $100 per ton of CO₂, highlighting SOC sequestration as a feasible and economically viable climate mitigation strategy. Our study findings underscore the trade-offs between food system transformation, land-use efficiency, and carbon storage, and emphasize that climate policies promoting bioenergy expansion can achieve substantial SOC gains, while dietary policies alone have limited impact if without strategic land management.

Oilseed rape-rice rotation with recommended fertilization and straw returning enhances soil organic carbon sequestration through influencing macroaggregates and molecular complexity

Hou et al. (2025) conducted a meta-analysis of field studies from 2019 to 2023 to evaluate the effects of noncontinuous flooding (NCF) practices on net carbon sequestration (NCS) in rice fields. The authors concluded that compared with continuous flooding (CF), NCF substantially enhances ecosystem-scale NCS, primarily by reducing methane (CH4) emissions while increasing photosynthetic carbon sequestration (PCS), despite a decrease in soil organic carbon (SOC) sequestration. This conclusion, however, warrants further scrutiny regarding methodological assumptions and data representativeness, potentially leading to a systematic overestimation of the carbon sequestration potential of NCF in rice systems. A primary concern lies in the calculation framework applied to rice systems, where PCS was directly added as a carbon sink component in the NCS budget. PCS represents short-term carbon input via plant photosynthesis, most of which is harvested and rapidly returned to the atmosphere through consumption, combustion, or decomposition. In agricultural systems, only carbon stored long term in soils or stable organic pools is considered true sequestration (Smith et al. 2020). Treating PCS as ecosystem-level carbon sequestration conflates “carbon input” with “carbon retention,” thereby overstating the mitigation potential of carbon sequestration pathways in croplands. This approach also diverges from IPCC guidelines, which emphasize long-term carbon storage as the accounting basis (Ogle et al. 2019). Additionally, since SOC sequestration was estimated by comparing SOC content before and after a single growing season, part of the PCS might have already been reflected in the SOC increment. Adding both PCS and SOC sequestration therefore raises the possibility of double counting in Hou et al. (2025). If the SOC change estimation method proposed by Guan et al. (2023) is adopted, NCS should be calculated based on both the net ecosystem exchange during the rice growing season and non-CO2 greenhouse gas emissions. SOC sequestration estimates themselves are also highly uncertain in Hou et al. (2025). Single-season SOC comparisons are vulnerable to sampling error, spatial heterogeneity, and seasonal variability. Numerous studies have shown that detectable SOC changes require multi-year monitoring due to the slow turnover and delayed stabilization of carbon inputs (Smith et al. 2020). Due to the fact that most studies did not incorporate straw return or organic amendments, the reported SOC increase under CF, which exceeds 2800 kg CO2-eq ha−1 in one season (see figure 7h, Hou et al. 2025), is unusually high. The values of SOC sequestration reported by Hou et al. (2025) substantially exceed estimates from comparable field conditions without external carbon inputs (Lessmann et al. 2022; Liu et al. 2024). Hou et al. also attributed the reduction in SOC sequestration under NCF to increased microbial biomass carbon, implying greater microbial activity and enhanced SOC decomposition. However, increased microbial biomass merely indicates a larger microbial biomass pool and does not necessarily imply higher microbial activity or increased SOC mineralization. Assessing microbial activity requires dynamic, process-based indicators such as respiration rates, enzyme activities, or mineralization fluxes, which were not evaluated in their analysis (Blagodatskaya and Kuzyakov 2013). Dataset constraints further weaken the conclusions. Only 23 observations from seven publications report complete NCS metrics, including yield, SOC, and non-CO2 greenhouse gas emissions, with limited geographic coverage and small sample sizes (Figure 1a). Unfortunately, studies published before 2019 were excluded by Hou et al. (2025), despite representing a comparable volume of relevant research (Nikolaisen et al. 2023). Incorporating these earlier data significantly reduces the estimated CH4 mitigation effect of NCF and may negate or even reverse its yield advantage (Figure 1b). While these factors are beyond the scope of this Letter, it is important to acknowledge that variations in water management practices and the use of organic amendments in rice systems can significantly affect emissions, yield, and SOC dynamics, and should not be overlooked in future assessments. Jinyang Wang: writing – original draft. Jianwen Zou: writing – review and editing. The authors declare no conflicts of interest. This article is a Letter to the Editor regarding Hou et al., https://doi.org/10.1111/gcb.70283. See also the Response to the Letter by Hou et al., https://doi.org/10.1111/gcb.70464. No new data were generated in this study. The data sources used for Figure 1 are documented in Hou et al. (2025) and Nikolaisen et al. (2023).