Livestock manure management plays a critical role in sustaining agricultural productivity, in the absence of no or a limited supply of inorganic fertilizers, while also enhancing soil organic carbon (SOC) storage. Yet, its effects on greenhouse gas (GHG) emissions remain uncertain. Using the Denitrification-Decomposition (DNDC) model, this study assessed the long-term impacts of pig and cattle manure applications on grass silage yield, SOC, and nitrous oxide (N₂O) emissions at a grassland site in Northern Ireland. The model was calibrated using SOC observations from 2012 to 2013 and grass yield observations from 2010 to 2013, and validated against 2016 measurements; N₂O performance was evaluated using annual cumulative emissions measured in 2016. It was then applied under future climate scenarios (SSP1–2.6, SSP3–7.0, SSP5–8.5) projected by the IPSL-CM6A-LR model. The DNDC model reproduced observed SOC, grass silage yield and annual N₂O emissions with acceptable performance, although N₂O emissions from the high cattle slurry treatment were underestimated. Across future SSP scenarios, high manure inputs increased silage yield and SOC storage, but also strongly enhanced N₂O-derived GWP estimates. The N₂O-derived GWP exceeded the SOC sequestration benefit by 2.0–5.7 times in several manure treatments. High pig manure produced the greatest yield and GHGI, whereas high cattle manure resulted in the largest SOC accumulation and N₂O emissions. Increasing manure loading enhanced SOC storage but also disproportionately increased N₂O-derived GWP and GHGI, particularly in the high-input treatments. These results indicate that manure-derived climate benefits are conditional rather than universal and depend strongly on manure type, application rate and future climate forcing.
Agroecological approaches harnessing in-field biodiversity have been highlighted as a sustainable way to reduce yield gaps, but long-term assessments of their ability to buffer production from weather extremes and increasing interannual and intraseasonal climate variability are scarce. Here, we analyze a 12-year dataset from 642 control vs. push-pull maize field pairs in western Kenya, where long-term climate trends include increasing temperatures and intensifying drought and rainfall. In push-pull, maize is intercropped with a fodder legume that improves soil fertility, suppresses weeds, and deters pests, and is bordered with fodder grasses attracting and suppressing the pests. We assess interactions between push-pull and climate effects on yields, stemborer pest damage and densities of parasitic weeds during the long and short rainy seasons, and how these drive push-pull effects on yield. Push-pull maize yields were always higher than control yields, but varying climate conditions affected the two field types differently. During the long rainy seasons, differences between push-pull and control yields were higher in years with high temperatures. Yield benefits of push-pull were also higher in years when dry spells were longer early in the long rainy season. During the short rainy seasons, push-pull increased yields, particularly when accumulated seasonal rainfall was optimal, while still doubling yield under very low or very high precipitation. Interactions between push-pull and climate variables were partly mediated by pests and weeds. Our results show that smallholder maize production using push-pull not only increases yields but also buffers adverse effects of weather extremes that are already becoming more frequent and intense.
Seasonal asynchrony between soil nitrogen release and plant uptake can increase hydrological nitrogen loss from pastoral ecosystems, but whether grassland management reorganization reduces this risk remains uncertain. We conducted a growing-season field study across natural, degraded and sown pastures on the Qinghai-Tibetan Plateau, comparing traditional individual household management with cooperative management. We quantified soil inorganic nitrogen, plant nitrogen demand, plant nitrogen stocks, biomass and surface-water total nitrogen, and used apparent nitrogen excess and a log supply:demand ratio to assess seasonal nitrogen coupling. Our results show that cooperative management reshaped nitrogen cycling, but its effects were strongly dependent on grassland type and season. In natural pastures, cooperative management generally strengthened plant nitrogen capture and reduced the log supply:demand ratio during much of the growing season. In degraded pastures, however, cooperative management maintained higher soil inorganic nitrogen and was associated with higher surface-water total nitrogen during several months, indicating that nitrogen retention did not improve immediately in severely degraded grassland. In sown pastures, cooperative management produced an early-season nitrogen surplus, likely linked to establishment inputs and low early plant demand, but later supported high aboveground production and lower surface-water nitrogen than individual management. Model-based analyses showed that plant nitrogen demand was the dominant negative predictor of nitrogen mismatch, whereas soil inorganic nitrogen was the strongest positive predictor of surface-water nitrogen. These findings indicate that cooperative management can improve nitrogen synchrony when plant demand is well aligned with nitrogen supply, but environmental benefits are not automatic and depend on grassland condition, input timing and hydrological pathways.
Contrasting organic amendment strategies are widely used in croplands, yet their effects on aggregate-scale carbon (C) and nitrogen (N) stabilization remain poorly understood. Here, we examined how maize straw return, green manure incorporation, and pig manure application regulated aggregate-associated C and N pools in a rainfed spring maize system. Through an 8-year field trial, we quantified aggregate stability, organic C and N fractions within aggregates, phospholipid fatty acids, extracellular enzyme activities, and amino-sugar-derived microbial necromass, and used partial least squares path modeling to elucidate the mechanisms driving mineral-associated organic matter (MAOM) accumulation. Across the two sampling years, green manure consistently produced the largest increase in mean weight diameter, by 58.46–140.16% relative to the control, indicating a stronger effect on aggregate stability. In contrast, straw and pig manure consistently increased MAOM-C and MAOM-N, particularly in micro-aggregates, where MAOM-C increased by 12.44–22.57% and 9.91–26.12%, and MAOM-N by 28.97–66.39% and 35.85–43.01%, respectively, relative to the control across the two sampling years. Straw was associated with higher C-acquiring enzyme activity and greater microbial necromass accumulation, whereas pig manure was associated with higher microbial biomass, stronger N-acquiring enzyme activity, and greater bacterial necromass formation. Path analysis further showed that MAOM in macro-aggregates was linked more directly to active microbial processing, whereas MAOM in micro-aggregates reflected the combined influences of amendment quality, microbial transformation, necromass formation, and aggregate-scale protection. Overall, different amendment strategies promoted distinct but complementary pathways of soil structural improvement and long-term C and N stabilization.
Cover crops are gaining attention in European cropping systems for their climate mitigation potential through soil carbon storage, reduced N₂O emissions, and increased surface albedo. However, the albedo effect, and the factors influencing it, remain poorly quantified under Danish field conditions. We conducted a field experiment in Taastrup, Denmark, from August 2020 to February 2021, measuring albedo in pure and mixed stands of winter rye, hairy vetch, and oilseed radish under two residual soil nitrogen levels, alongside a bare soil control. Albedo was recorded at multiple time points during the cover crop growth period, including periods of partial snow cover, and converted into global warming potential (GWP) under three snow scenarios: no snow, midwinter snow, and late-winter snow. Our results show that all cover crops significantly increased albedo relative to bare soil under snow-free conditions, with mixtures and species including the nitrogen-fixing vetch exhibiting the largest increases. Elevated residual soil nitrogen accelerated canopy development, leading to earlier and higher peak albedo. Snow presence and timing strongly influenced the simulated mitigation effect: mid- and late winter snow reduced GWP by 16% and 27%, respectively, compared with the snow-free scenario. This study demonstrates that, in northern mid-latitudes, cover crops can enhance surface reflectivity and contribute to climate mitigation, with the magnitude of the effect determined by species traits, soil nitrogen status, and snow cover presence and timing. Further work is needed to test the generality of these findings across different establishment timings and snow cover regimes.
Ecosystem engineers modify community structure and ecological functions through bioturbation, but how their activities modulate ecosystem multifunctionality (EMF) remains unclear, particularly when multiple engineers coexist. Here, we investigated the differential impacts of plateau zokor (Eospalax baileyi), plateau pika (Ochotona curzoniae), and ants (Camponotus) on aboveground (AEMF), belowground (BEMF), and overall EMF in alpine grasslands. Our results reveal contrasting effects of these three subterranean animals on AEMF, BEMF, and EMF through distinct mechanisms. AEMF and EMF were significantly lower in plateau zokor burrowing plots than in controls. By contrast, plateau pikas had minimal effects on both AEMF and BEMF, resulting in no net change to EMF. Ants nesting plots showed a functional trade-off that counterbalanced AEMF losses with BEMF gains, leaving overall EMF unchanged. Soil nitrogen dynamics emerged as the primary driver of EMF variation across all species. These findings highlight that the net impact of burrowing animals on ecosystem functioning arises from the integration and potential trade-offs between aboveground and belowground functional responses, challenging simplistic classifications of these species as either beneficial or detrimental. Our results underscore the need for species-specific management strategies and emphasize the importance of maintaining stable population densities to preserve ecosystem multifunctionality in alpine grasslands.
Traditional wood-pastures are agroforestry systems shaped by long-term low-intensity management. However, the relative importance of drivers of plant diversity and forage quality operating at different spatial scales in these systems remains poorly understood. We investigated 30 traditional wood-pasture sites in Transylvania (Romania) by integrating drivers i) at the large-scale: historical Corona satellite imagery from 1964, contemporary land-cover data, and CHELSA climatic data; ii) at the intermediate-scale: tree and woody configuration; and iii) at the fine-scale: soil surveys. We evaluated the interaction among landscape structure, site factors, plant diversity and forage quality. We analysed long-term changes in land use and woody cover across multiple spatial scales within wood-pasture mosaics. Using linear models and variation partitioning, we assessed the multi-scale environmental determinants on plant taxonomic and functional diversity, and forage quality of the wood-pastures. Landscape composition remained largely stable over six decades, although woody cover declined at most sites, indicating fine-scale structural change within a persistent land-cover mosaic. Climatic conditions such as annual precipitation was positively associated with forage quality and functional richness of specific leaf area, while mean annual temperature and pasture loss were negatively associated with functional richness of plant height. Current forest cover was related to functional richness related to leaf economics and seed mass, whereas soil carbon showed a positive relationship with species richness and leaf-trait diversity. Woody cover was linked to higher species richness but lower forage quality, suggesting a structural trade-off between biodiversity and palatability. Current land use explained the largest proportion of variation in forage quality and species richness, whereas climate and land-use change were more strongly associated with functional composition. These results support hierarchical environmental filtering, whereby regional climate and local habitat structure constrain community assembly more strongly than landscape composition. Our findings about this traditional multifunctional landscape highlight that conserving and restoring wood-pasture functionality requires combined management practices that optimise woody cover, grazing intensity, and soil quality.
Agricultural intensification is a major driver of biodiversity loss, yet its consequences for the functional structure and resilience of amphibian communities remain incompletely understood. We evaluated how conversion of native forest to agriculture and commercial silviculture reshapes anuran assemblages across 30 breeding sites in southern Brazil (10 sites per habitat type). We quantified taxonomic diversity, complementary facets of functional diversity, community-weighted traits, and environmental conditions. Coverage-standardized taxonomic diversity was consistently higher in silviculture than in agriculture, whereas native forest showed intermediate values and overlapped with both converted habitats. Nevertheless, native forest retained forest-associated species that were rare or absent from production systems, demonstrating that similar local diversity does not imply equivalent conservation value. Functional richness and evenness were broadly maintained across habitats, whereas functional dispersion varied among land uses. Individual community-weighted traits also showed substantial overlap, although ordinations indicated compositional and functional reorganization associated with land cover, shading, and environmental heterogeneity. The abundance of the invasive Lithobates catesbeianus was not associated with taxonomic or functional diversity in site-level regressions. Our findings show that agriculture and silviculture impose contrasting, non-monotonic filters on anuran assemblages. They further demonstrate that effective species diversity alone is insufficient to characterize land-use effects, because species identity, functional organization, and habitat context provide complementary information. Conservation strategies should therefore prioritize native-forest breeding sites while maintaining riparian vegetation, wetland integrity, terrestrial refuges, and landscape connectivity within production mosaics.
Cereal crop residues could become increasingly used to produce bioenergy as part of the European green transition, which may increase the amount of such residues removed from fields. At the same time, on-field residue retention is an important regenerative agriculture practice with positive effects on soils. Thus, excessive residue removal can be environmentally unsustainable at the field level. Yet, the effects of residue removal on local biodiversity – especially aboveground – are not well known. Given the large land footprint of cereal production in Europe, the impacts of changing cereal residue management on biodiversity could be substantial. Here, landscape-scale cereal residue management data, field measurements of local biodiversity, cereal yield and other environmental data were combined in statistical models to estimate local biodiversity in cereal cropland in Europe and investigate the effects of on-field residue retention. Local biodiversity in cereal cropland was poor relative to other land uses, but was positively associated with landscape-scale on-field residue retention, with significantly greater local biodiversity in cereal cropland in landscapes with a high proportion of residues (≥ 70%) left on fields. On the other hand, local biodiversity in cereal cropland was negatively associated with landscape-scale cereal yield. Cereal residue retention was a stronger predictor of local biodiversity in cereal cropland than cereal yield. The results presented improve current understanding of the relationships between local biodiversity and landscape-scale cereal residue management and crop yield, with relevance for biodiversity conservation, agricultural management and energy production in Europe.
Rangeland degradation is a global environmental challenge; however, intense debate persists between equilibrium (focused on the negative effects of grazing intensity) and non-equilibrium (emphasizing livestock mobility for adapting to climate variability) theories in rangeland ecology. In recent years, an integrative theory advocating the “coexistence of equilibrium and non-equilibrium” has emerged to reconcile this debate. However, few studies have examined this integrative theory via post-hoc evaluations of management experiments. Here, we conducted a 4-year field experiment with five grazing modes (varying in grazing intensity and rotational management) to evaluate the integrative theory from ecological and economic perspectives. Our results reveal that grazing intensity and livestock mobility (ensured by rotational grazing) affect rangeland ecosystems. Ecological variables demonstrated non-uniform responses to these two factors. Grazing intensity exerted a stronger effect than livestock mobility in our experimental site. Policies would provide clear ecological benefits when integrating equilibrium (e.g., carrying capacity-based management) and non-equilibrium (e.g., rotational grazing to maintain livestock mobility) elements. However, implementing mobility-based rotational grazing demands targeted financial support to overcome initial economic and labor constraints. Therefore, we recommend a progressive, stepping-stone approach within current property rights, prioritizing the reconstruction of microscale mobility through household-level rotational grazing supported by specialized compensation mechanisms. Once institutionalized, this localized integration may facilitate the gradual incorporation of advanced, large-scale non-equilibrium elements in subsequent stages. Future policies should be guided by standard two-factor experiments across multiple regions, integrating ecological and economic evaluations under diverse precipitation regimes and climate variability to refine China's next-generation grazing management strategies.
Microbial cell size is a key functional trait influencing soil ecological functions. Laboratory cultivation experiments have indicated that resource availability can influence microbial cell size. However, few studies have been conducted in field soil ecosystems. To fill this knowledge gap, we collected 96 samples from five sites across eastern China with different fertilization regimes and combined magnetic nanoparticle-mediated isolation, single-cell image recognition, and high‑throughput sequencing analyses. We found that the fertilization, particularly organic fertilization, promoted cell enlargement in spore-forming Bacilli more through enhancing soil resource availability, rather than through altering community composition. To unravel the underlying mechanisms, we further conducted manipulative experiments focusing on a typical Bacillus strain, a pivotal species in agroecosystems, along with metagenomic analysis. The results indicated that under our experimental conditions, organic carbon played a more important role than nitrogen in shaping cell size. Furthermore, increased organic carbon induced a shift in their metabolic strategy from resource acquisition to fast growth orientation. Taken together, our work highlighted the important role of soil resource availability, especially the effect of organic carbon on microbial cell size, which provides a potential new perspective for understanding how soil microbial functional traits respond to intensified anthropogenic activities.
Previous work at our study site had shown a loss of soil carbon (C) when a pasture was converted to maize cropping. Here, we studied whether, or how rapidly, lost C was recovered after returning to pasture. This included continuous eddy-covariance and biomass measurements, and modelling with the ecophysiological model CenW. We obtained good agreement between modelled and observed weekly averaged C and water exchange rates, with Nash-Sutcliffe model efficiencies ranging from 0.63 for net ecosystem productivity to 0.89 for evapotranspiration rates. The site C balance remained near neutral over the first two years after conversion back to pasture, but displayed considerable intra-year variability. Over the next two years, there was still no C recovery. Instead, even more C was lost, for an eventual loss of about 3 tC ha−1.We tested whether unusually dry summers might have contributed to the lack of C recovery, but a scenario analysis by CenW did not support that hypothesis. Instead, our analysis suggested that unusually warm conditions, especially over the last measurement year, may have contributed to further C losses. The scenario analysis also identified the importance of pasture management, with soil C consistently decreasing when grazing commenced at lower biomass thresholds, or when animals grazed to lower remaining biomass. Biomass removal by mechanical harvesting also negatively affected the C balance.These results provided important insights into the key environmental and management factors that together determine site C balances. While the transition between cropping and perennial pasture provided one important factor that influenced the net ecosystem C balance, various management and environmental factors could also critically affect it.
Recent soil science research highlights that roots are a key source of soil organic C (SOC) in agricultural systems because root inputs are more efficiently transformed into soil organic matter than shoot inputs. We conducted a systematic meta-analysis of cropping system studies to evaluate the effect of enhanced living root continuity on SOC sequestration efficiency (i.e., SOC stock per unit C input) across diverse environments. Our analysis included 21 studies and 57 observations that measured C inputs and SOC stocks in paired systems of enhanced living root continuity and control systems. The paired systems included: continuous crop systems vs. fallow-inclusive systems, cover crop vs. no cover crop systems, and perennial-inclusive rotations vs. annual-only rotations. We analyzed the effect of enhanced living root continuity on average annual C inputs, C stocks, and SOC sequestration efficiency. Average annual C inputs were 51% and 21% greater in perennial systems and continuous cropping systems, respectively, relative to their corresponding control systems, whereas cover crop-inclusive systems did not differ significantly from no-cover-crop systems. The SOC stocks were 15% and 8% greater in perennial systems and continuous cropping systems, respectively, and tended to be greater in cover crop-inclusive systems than in no-cover-crop systems (p = 0.095). Because perennial and continuous cropping systems increased C inputs proportionally more than SOC stocks, they exhibited lower SOC sequestration efficiency than their respective control systems. Thus, our study found that cropping systems with enhanced living root continuity improve SOC storage primarily by increasing total C inputs rather than by enhancing the efficiency of C sequestration.
Restoration measures play a critical role in the recovery of fragile alpine degraded grassland ecosystems on the Qinghai–Tibet Plateau. However, the relationships among plant communities, soil properties, and microbial communities under integrated restoration strategies remain insufficiently understood. In this study, we investigated degraded alpine grasslands of the Qinghai–Tibet Plateau using a completely randomized experimental design, which included eight treatments: no intervention as the control (C), toxic weed removal (W), fertilization (F), reseeding (S), and their combinations—fertilization + weed removal (FW), fertilization + reseeding (FS), fertilization + reseeding + weed removal (FSW), and reseeding + weed removal (SW). By assessing plant community characteristics and soil physicochemical properties in conjunction with high-throughput sequencing of soil microbial communities, we evaluated the effects of different restoration measures on plant communities, soil conditions, and microbial assemblages and further employed multivariate statistical analyses to examine their interrelationship. For plant productivity, the FS treatment produced the highest total aboveground biomass, which was 86.55% higher than that of the control (q < 0.05). For soil responses, FW significantly increased soil total organic carbon, total nitrogen, total phosphorus, and nitrate nitrogen, whereas FS significantly increased ammonium nitrogen (q < 0.05). For microbial communities, FW significantly increased fungal Shannon and Simpson indices, while the higher bacterial α-diversity values under S and FS did not differ significantly from the control. The S treatment showed the highest mean degree and clustering coefficient in the bacterial co-occurrence network. FS showed higher predicted potentials for bacterial aerobic chemoheterotrophy and fungal saprotrophy, whereas F and FW showed higher predicted nitrate-reduction and arbuscular-mycorrhizal potentials. NMDS ordination showed clearer treatment-related separation in fungal β-diversity than in bacterial β-diversity, indicating a more evident response of fungal community composition to the restoration treatments. Collectively, this single-time-point assessment provides an integrated view of early plant, soil, and microbial responses to the restoration treatments. Given the limited temporal and spatial scope and the predictive nature of the microbial functional analysis, these findings should be regarded as exploratory and require longer-term validation.
The continuous rise in atmospheric CO₂ concentration and its impact on global climate underscore the urgency of reconciling food security with carbon emission reduction. While leguminous green manure incorporation offers ecological benefits, the synergistic effects of its integration with reduced chemical nitrogen fertilizer application on soil respiration components and underlying mechanisms remain poorly understood. A three-year field experiment (2023 −2025) was conducted in an oasis irrigation area of Northwest China, evaluating five treatments under green manure incorporation: Traditional nitrogen application (N100), nitrogen reduction by 10% (N90), nitrogen reduction by 20% (N80), nitrogen reduction by 30% (N70), and nitrogen reduction by 40% (N60). The results showed that compared with the N100 treatment, the N80, N70, and N60 treatments significantly reduced soil respiration rate (Rs), with reductions ranging from 12.8% to 22.9%, an effect primarily attributed to the suppression of microbial heterotrophic respiration (Rh). In addition, the N80 treatment optimized soil physicochemical properties and increased the relative abundance of key microbial taxa such as Ascomycota and Gemmatimonadota. These synergistic changes provided critical evidence for explaining the observed agricultural carbon mitigation effect. Random forest analysis revealed that soil pH and soil water content (SWC) were key drivers of bacterial communities, while fungal communities were mainly regulated by soil NO₃⁻-N and NH₄⁺-N content. Structural equation modeling (SEM) further confirmed that nitrogen reduction under green manure incorporation affected heterotrophic respiration through a multi-level "physical-chemical-microbial" pathway, ultimately regulating soil respiration intensity. These findings demonstrate that nitrogen reduction by 20% combined with green manure incorporation represents a promising synergistic strategy for reducing soil CO₂ emissions, improving soil fertility, and regulating microbial communities in oasis irrigation agricultural systems.
Green manuring and tillage are long-established agricultural practices that regulate nitrogen (N) availability in cropping systems. However, the agronomic and biogeochemical outcomes of green manures as organic soil amendments remain insufficiently resolved under realistic field management, where residues are either incorporated (typically under conventional tillage) or surface-retained (under no-tillage). We conducted a three-year field experiment in upland arable soils to evaluate the interactive effects of green manure type (Control; fallow with urea fertilization, F; barley, B; hairy vetch, H; and barley-hairy vetch mixture, B+H) and tillage regime (conventional tillage, CT; no-tillage, NT) on maize ear yield, nitrogen use efficiency (NUE), apparent nitrogen recovery (ANR), and N accumulation in soil. Over the three years, CT−H and NT−F showed progressive improvements in crop yield and N-related indices, with yields approaching those of the conventional benchmark by Year 3. CT−B + H also exhibited a balanced agronomic profile, suggesting potential as an alternative management option. Across treatments, CT was associated with faster N turnover and relatively higher ANR, whereas NT consistently increased soil N accumulation, indicating enhanced N retention. Microbiome analyses further revealed distinct compositional and functional shifts linked to tillage systems. Soil in CT was dominated by Firmicutes, with notable enrichment of Sporosarcina, and exhibited higher relative abundance of KEGG pathways related to N metabolism and amino acid turnover, consistent with accelerated N mineralization. In contrast, NT soils were enriched in Acidobacteriota and pathways related to carbohydrate metabolism, coinciding with greater soil N accumulation. Collectively, these findings show that green manures function as effective organic amendments, but their benefits for crop productivity and soil N retention depend strongly on how residues are managed. They also highlight a trade-off between short-term N availability and long-term soil N storage and point to practical green manuring-tillage combinations that sustain crop productivity while improving N management.
Vertisols are widespread and generally more resistant to degradation than other soil types. Straw return is widely promoted to increase soil organic carbon (SOC) in clay-rich Vertisols, but how straw inputs affect the accumulation of plant- and microbial-derived C within particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) remains poorly understood. Using a 42-year fertilization experiment with four treatments (Control, NPK, NPK with half-rate wheat straw return [NPKLS], and NPK with full-rate wheat straw return [NPKHS]), we combined physical fractionation with biomarker analyses (lignin phenols and amino sugars) and microbial life-history metrics (bacterial and fungal K/r ratios) to quantify plant- and microbial-derived C in POC and MAOC and to further examine their relationships with life-history strategies. Long-term straw return increased SOC by 34.7%–51.7% relative to the Control, driven by concurrent increases in POC and MAOC. Straw return increased plant-derived C proxies in POC (S-type phenols) and MAOC (S- and V-type phenols). Straw return markedly increased fungal and bacterial necromass C in both fractions, with greater relative increases in POC than in MAOC under NPKHS (p < 0.05). Straw return differentially affected microbial life-history strategies, with the bacterial K/r ratios significantly lower under NPKLS and fungal K/r ratios markedly higher under NPKHS. Structural equation modeling showed that the fungal K/r ratio was positively correlated with the accumulation of plant- and microbial-derived C in POC, whereas the bacterial K/r ratio was negatively correlated with their accumulation in MAOC. Overall, sustained straw return enhanced the accumulation of plant- and microbial-derived C in SOC fractions, mediated by shifts in microbial life-history strategies in Vertisols.
