Trade-offs between crop yield and soil organic carbon sequestration under straw return across cropping systems

Although arbuscular mycorrhizal fungi (AMF) have been assumed to facilitate soil organic carbon (SOC) sequestration, they also regulate SOC decomposition via specific interactions with saprotrophs. We tested AMF hyphal impacts on SOC dynamics (e.g. labile C vs persistent C) under monoculture conditions with different grasses (e.g. Leymus chinensis and Stipa grandis) using an in-growth core method. Although the total SOC pool was unaffected by the presence of AM fungal hyphae, the proportional composition of labile and persistent C within SOC pools differed significantly between treatments with and without hyphal access. The presence of AM fungal hyphae from L. chinensis was associated with increased abundances of actinomycetes and Gram-positive bacteria, alongside the higher activity of polyphenol oxidase that breaks down persistent soil C, leading to a higher proportion of labile C in the SOC pool. Under S. grandis, however, hyphal presence corresponded with a greater abundance of Gram-negative bacteria that often can degrade labile soil C, resulting in a higher proportion of persistent C in the SOC pool. The influence of AM fungal hyphae on SOC depends on the identity of host plants and thus shifts in plant community composition may strongly alter SOC dynamics in grasslands.

Abstract Returning plant residue to farmland maintains or enhances the fertility and the investigation of how residue management strategies affect soil organic carbon (SOC) and labile organic carbon (LOC) fractions is crucial for addressing concerns related to agricultural sustainability. However, knowledge gaps remain about how these C fractions change in deep soil (>40 cm) under different strategies. A 10‐year field experiment (2012–2021) in Northeast China compared three strategies: residue covered on the surface (RC), residue incorporated into 0–20 cm soil (RI), and residue removed (CK). In 2021, the vertical distribution (0–90 cm) of SOC and five LOC fractions (microbial biomass carbon [MBC], dissolved organic carbon [DOC], particulate organic carbon [POC], easily oxidizable carbon [EOC], and light fraction organic carbon [LFOC]) was analyzed. The results showed that SOC and LOC fractions generally decreased with increasing soil depth, except for the RI treatment in the 0–20 cm layer. The largest treatment differences occurred in the 0–5 cm layer, where RC had significantly higher SOC and LOC concentrations than RI. LOC fractions exhibited similar sensitivity trends in RC (14.82%–105.48%) and RI (13.39%–58.54%) relative to CK. RI resulted in the highest SOC and LOC contents in the 5–20 cm layer, while RC exceeded RI and CK below 20 cm. Below 40 cm, the highest SOC content was mostly observed in RC, but no significant differences among the three treatments were detected in the 20–40 cm layer. POC proportions in the 0–90 cm profile ranged from 30.06% to 5.34% (RC), 26.60% to 4.76% (RI), and 21.75% to 4.78% (CK). Pearson correlation analysis and principal component analysis revealed that SOC changes were primarily driven by POC, EOC, and LFOC, while MBC and DOC played a secondary role due to their high lability. This study highlights that overlooking deep subsoil carbon dynamics masks key opportunities for SOC sequestration and may lead to incomplete conclusions about the impact of residue management on long‐term carbon storage in Mollisols of Northeast China.

This review synthesizes current knowledge on the life cycle assessment (LCA) of swine production systems, emphasizing nutrient management, nitrous oxide (N₂O) mitigation, and manure treatment strategies that enhance sustainability. Although swine are not the largest contributors to agricultural greenhouse gas (GHG) emissions, their environmental footprint remains substantial due to feed production and manure management. Integrated nutrient management—through precision nitrogen (N), phosphorus (P), and potassium (K) application—combined with manure reuse, can significantly reduce N losses, improve soil organic carbon (SOC) sequestration, and mitigate N₂O emissions. Emerging manure treatment technologies such as composting, anaerobic digestion (AD), and biochar production also offer co-benefits of nutrient recovery and energy generation. The review highlights that integrating these strategies within regenerative agricultural systems—using practices like reduced tillage, cover cropping, and circular bioeconomy approaches—improves soil health, minimizes GHG emissions, and promotes resilient crop-livestock systems. Overall, this synthesis underscores that coupling nutrient management with innovative manure treatment and emission-mitigation technologies is essential for advancing the sustainability of swine production and reducing its environmental impact.

Data-driven precision optimization of straw and N-fertilizer input to balance SOC sequestration and stability in China’s intensive croplands

• Earthworms alone increase large macroaggregates but not intra-aggregate SOC. • Earthworms and residue incorporation increase large macroaggregates by 67.4%. • Earthworms and residue incorporation synergistically increase SOC by 21.7%. • Sufficient residue inputs resolve the “earthworm dilemma” for SOC sequestration. Soil organic carbon (SOC) sequestration is critical for climate change mitigation. Anecic earthworms, as key ecosystem engineers, are hypothesized to promote SOC storage by forming stable soil aggregates, but their interaction with plant residue inputs remains unclear. To address this knowledge gap, we conducted a one-year field experiment in a poplar plantation to investigate the individual and combined effects of earthworm inoculation ( Metaphire guillelmi ) and poplar leaf residue addition (surface mulching vs. soil incorporation) on SOC dynamics. Compared to the control, residue incorporation and earthworm inoculation alone increased the proportion of large macroaggregates (>2000 μm) by 23.3% and 37.9%, respectively. However, their combination yielded a significant synergistic effect, increasing large macroaggregates by 67.4%. Notably, earthworms alone did not increase SOC concentration within aggregates and marginally reduced whole-soil SOC (≈ 0.46%), whereas their combination with residue addition, either mixed into soil or placed on the soil surface, significantly boosted SOC in large macroaggregates and raised whole-soil SOC by up to 21.7%. Structural equation modeling confirmed that residue addition directly enhanced SOC pools, whereas earthworms acted primarily by promoting soil large macroaggregates formation and increasing aggregate stability (quantified by mean weight diameter). This synergistic interaction resolves the “earthworm dilemma” by offsetting short-term carbon mineralization through long-term SOC protection in stable aggregates. We conclude that anecic earthworms (e.g., Metaphire guillelmi) act as critical regulators of soil physical structure, and their contribution to soil organic carbon sequestration efficiency depends critically on their interaction with fresh plant residue inputs. Our findings provide actionable insights for climate-smart forestry, highlighting that integrating earthworm conservation with optimized residue management is a key strategy to strengthen terrestrial carbon sinks in forest plantations.

Soil organic carbon sequestration over 50 years in resampled afforestation chronosequences on former cropland.

Achieving net-zero greenhouse gas (GHG) emissions in agriculture is a central objective of climate policy frameworks such as the Paris Agreement. This study explored the feasibility and trade-offs of achieving net zero at the farm level by combining life cycle assessment with modeling of soil organic carbon (SOC) stocks. Four case-study farms, two crop and two dairy, in Italy, the United Kingdom (UK), France, and Germany, and 11 mitigation actions were assessed under two 20-year eco-design scenarios: one maintaining ≥90% of baseline productivity (PM), and one achieving net zero. The scenarios combined nature-based solutions (e.g., organic fertilization, cover crops) with technological interventions (e.g., feed additive, solar power). Estimated GHG emissions decreased greatly, but SOC sequestration alone was insufficient to achieve net zero while maintaining productivity. Under the PM scenario, the Italian, French, and German farms still emitted 51%, 62%, and 84% of baseline emissions, respectively. The UK crop farm achieved net zero under the PM scenario, but had the highest ecotoxicity impact per ha, 11% higher than that of the Italian crop farm. Mitigation effectiveness depended on soil- and crop-management practices, baseline GHG emissions, and carbon inputs. Assumptions about the 20-year amortization window, nutrient cycling, and indirect GHG emissions influenced trade-offs between environmental impacts and productivity. Net zero may be pursued more effectively through cooperation among farms at the landscape or sector level. Assessing the entire agricultural value chain, improving model calibration, and supporting long-term transitions through policies will be essential for developing climate mitigation actions adoptable across European agriculture.

Synergistic application of biochar with organic fertilizer enhances soil carbon sequestration by optimizing mineral-associated organic matter formation pathway contributions.

Arbuscular mycorrhizal symbiosis enhances microbial contribution to mineral-associated organic carbon persistence in the soil: Insights from soil microbial community and microbial necromass carbon

Triple impact: Biochar, no-tillage, and cover crops for soil carbon enhancement and climate resilience in soybean farming

Alpine grassland restoration, a critical strategy for enhancing soil organic carbon (SOC) sequestration in high-altitude ecosystems, profoundly influences plant-soil-microbe interactions that govern the magnitude of carbon (C)-climate feedback. However, the mechanisms driving plant and microbial regulation of SOC mineralization (i.e., soil CO2-C release) during degraded alpine grassland restoration remain unresolved, limiting predictions of SOC cycling in these vulnerable ecosystems. Here, by integrating passive and active restoration experiments with aerobic incubation, high-throughput sequencing, and biomarker analyses, we disentangled how restoration-induced shifts in SOC composition (plant- and microbial-derived C) and microbial activity and diversity regulate soil CO2-C release in degraded alpine grassland on the Qinghai-Tibetan Plateau. Our results showed that soil CO2-C release increased significantly with restoration progression under both passive and active approaches. Alpine grassland restoration markedly enhanced plant-derived C accumulation and its SOC contribution, while microbial-derived C remained unchanged due to reduced necromass accumulation coefficients. Notably, although active restoration accelerated plant-derived C accumulation, its oxidation decomposition degree was lower compared to passive restoration and even to unrestored heavily degraded grasslands, increasing SOC pool lability. Fungal community restructuring, particularly in the saprophytic fungal community, emerged as a hallmark of restoration. More importantly, we found that elevated soil CO2-C release during degraded alpine grassland restoration was not primarily mediated by microbial activity and diversity shifts but was strongly linked to divergent plant- and microbial-derived C accumulation patterns, especially the dynamics of plant-derived C. These insights underscore the critical roles of plant- and microbial-derived C redistribution in grassland restoration and suggest new mechanisms for restoration-induced soil C dynamics.

Cover crops potentially enhance soil organic carbon sequestration to offset greenhouse gas emissions without yield penalty towards net-zero rice agriculture

Rubber based agroforestry systems enhance soil organic carbon sequestration through changes in soil properties and microbial community structure

Conservation Agriculture (CA) is pivotal to achieve sustainable intensification, yet the global efficacy of its core practice, conservation tillage (CT), remains debated regarding the trade-offs between crop productivity and ecosystem services across diverse environmental contexts. Here, we conducted a second-order meta-analysis, synthesizing 69 published meta-analyses, to elucidate the context-dependent drivers regulating the "win-win" outcomes of CT. Globally, CT reduced greenhouse gas (GHG) emissions by 5%, increased soil organic carbon sequestration by 21%, increased soil fertility by 11%, and reduced soil erosion by 12%, all while maintaining crop yields comparable to conventional tillage. However, CT can also emerge as a partial trade-off between crop yields and ecosystem services, notably between crop yield and GHG mitigation. These trade-offs were strongly regulated by climatic and edaphic conditions as well as management intensity. For instance, strong synergies between crop productivity and multiple ecosystem services were more pronounced in (semi-)arid regions characterized by low temperatures and low precipitation, as well as in coarse-textured alkaline soils. Furthermore, integrating CT with residue retention and crop rotations maximized these synergies, mitigating potential yield penalties. Collectively, our synthesis demonstrates that context-specific refinement of CT implementation is essential to reconcile agricultural productivity with ecosystem services, thereby advancing climate-resilient agricultural systems globally.

Effect of soil organic carbon sequestration during subtropical forest succession

Straw tissue quality influence the formation pathways of soil organic carbon via living microbes or microbial necromass in a Mollisols, Northeast China

Agricultural ecosystems play a significant role in global food security and climate mitigation through crop production and soil organic carbon sequestration. It is well-established that potassium fertilization enhances crop yield in potassium-deficient regions; however, the factors driving crop yield responses to potassium remain insufficiently characterized at a large scale. Moreover, despite the significant roles of soil organic carbon in soil health and global carbon cycling, the effect of potassium on soil organic carbon in croplands has been less studied. Herein, we collect data from 1185 observations in agricultural ecosystems to conduct a meta-analysis study. We find that potassium fertilization increases cereal yield and soil organic carbon by 19.3% and 4.4%, respectively. Mean annual precipitation and experimental duration are the most important factors affecting potassium effects on cereal yield and soil organic carbon, respectively. Specifically, potassium effects on cereal yield increase with mean annual precipitation, and the potassium-induced increase in soil organic carbon is significant only after long-term (> 20 years) potassium fertilization. Our findings suggest that, in addition to nitrogen and phosphorus, potassium is also crucial for not only cereal yield but also soil carbon sequestration, which should be fully valued in future soil nutrient management, especially in potassium-deficient regions.

ABSTRACT This study evaluates greenhouse gas emissions associated with a multifunctional conservation-oriented grazing system in Latvia. The inventory covers methane from enteric fermentation, nitrous oxide from manure deposited on pasture, and carbon dioxide from fuel use for hay-related operations and transport within the defined system boundary. Total emissions for 2022 were estimated at 350 t CO2e and were dominated by enteric methane. Emission intensities depend strongly on the functional unit and animal pathway: annual herd-level intensities reflect marketed output in the assessment year, while lifetime-pathway results show much lower carcass-weight intensities for bulls finished at around 4 years than for breeding cows culled after long service, due to cumulative emissions over longer lifespans. The results illustrate the central trade-off in multifunctional grazing: extensive management and habitat stewardship can support biodiversity and grassland maintenance, while longer animal lifespans and lower growth rates increase product-based emission intensities. Soil organic carbon (SOC) sequestration was not credited in the footprint due to high uncertainty in short-term SOC change estimates; longer-term, stratified monitoring is required to assess sequestration dynamics and permanence. Future work should integrate quantified biodiversity and habitat-condition indicators alongside improved, regionally calibrated emission parameters to support more policy-relevant assessments of extensive multifunctional grazing systems.

Carbon farming is the collection of agricultural best practices specifically designed to maximize the capture and long-term storage of atmospheric carbon dioxide in soils and plant biomass, while simultaneously reducing greenhouse gas emissions from cultivation practices. Carbon farming can be viewed as a promising pathway to simultaneously address climate change mitigation, soil degradation, and farmer welfare. For example, if the entire agricultural cropland in India practices carbon farming, this will spectacularly offset about 50% of emissions from the country’s annual transport-sector emissions. However, practical deployment of carbon farming is constrained by scientific challenges, inherent complexity, and fragmented understanding across disciplines. As a result, in India, for example, fewer than 1% of farmers participate in carbon credit programs. This inter-disciplilinary, expository survey offers the first unified treatment of carbon farming for practitioners, policymakers, and researchers. The survey integrates insights from agronomy, soil science, climate science, measurement, reporting, and verification (MRV), economics, carbon markets, and policy design. We begin by establishing the conceptual foundations of soil organic carbon dynamics and agricultural carbon sequestration, and compare carbon farming with the paradigms of sustainable, regenerative, and organic agriculture. We then present a comprehensive landscape analysis of carbon-farming best practices, including both generic and crop-specific interventions, and systematically examine their co-benefits and trade-offs. The paper offers a rigorous review of MRV frameworks, emerging digital MRV technologies, and the carbon-credit project life cycle, followed by a structured analysis of voluntary and compliance carbon markets. Drawing on six representative case studies, we synthesize implementation models, successes, and failure modes. Building on this integrated analysis, we highlight key scientific, economic, institutional, and adoption challenges, and propose potential remedies to make carbon farming a credible, scalable, and attractive proposition for global agriculture. We finally highlight the important role that artificial intelligence, game theory, and computation can play in improving various dimensions of carbon farming.