CONTEXT: Climate change affects water resources and soil fertility in northern China. Hence, understanding the drivers and relationships between spring maize water use efficiency (WUE) and soil fertility is critical. OBJECTIVE: To assess how spring maize WUE responds to changing soil fertility in northern China under future climate scenarios and propose region-specific strategies. METHODS: Three CMIP6 circulation models were coupled with the validated DSSAT-CERES-Maize model to simulate WUE and soil organic carbon (SOC) from 2021 to 2100 under baseline, SSP126, SSP245 and SSP585 scenarios. RESULTS AND CONCLUSIONS: WUE increased under SSP126 (1.90 kg m(-3)) and SSP245 (1.84 kg m(-3)), but declined under SSP585 (1.67 kg m(-3)), compared to the baseline (1.75 kg m(-3)). SOC showed a notable increase until 2070, then stabilized. Spatially, WUE ranked northeast China (NE) > northwest China (NW) > north China (NC), while SOC followed the pattern NE > NC > NW, with reductions averaging 12.5-18.2%. In NC, WUE peaks at moderate soil fertility and remained stable; in NE, it steadily increased with increasing soil fertility; and in NW, WUE increased to good fertility then declined. Yield dominated WUE at moderate and above fertility, while evapotranspiration was the primary driver under poor fertility in NW and NC. SIGNIFICANCE: These findings highlight that future WUE improvement depends on region-specific management. In NE, enhancing SOC through organic-inorganic fertilization can effectively boost yield and thus raise WUE. In NC and NW, WUE is improved by reducing evapotranspiration through water-saving practices.

Understanding how land-use affects runoff-pathway partitioning is important for controlling sediment and nutrient export from steep agricultural slopes. We established three replicate 30 m × 2 m runoff plots for each of three land-use types—cropland, pastureland, and shrubland—and separately monitored surface runoff, shallow lateral flow intercepted at 30 cm depth (SLF), sediment loss, and nitrogen (N) and phosphorus (P) export in a high-elevation mountainous region of southern China. Nine temporally clustered rainfall events spanning three rainfall-intensity classes were selected from a broader monitoring record. Cropland produced the highest mean runoff volume (8928 mL), compared with shrubland (3640 mL) and pastureland (2125 mL). Surface runoff accounted for 92.7% of the combined runoff from cropland, whereas surface runoff and SLF contributed more evenly in pastureland and shrubland. Under heavy rainfall, SLF exceeded surface runoff in both vegetated land-use types but remained a minor pathway in cropland. Cropland also produced the highest mean surface-runoff-associated sediment loss (1845 g), exceeding pastureland (434 g) and shrubland (238 g). Runoff-pathway redistribution differentiated nutrient export. Phosphorus loss from cropland was closely associated with sediment-bearing surface runoff, whereas SLF was the main pathway for total nitrogen (TN), water-soluble nitrogen (WSN), and nitrate nitrogen (NO₃−-N) loss from pastureland and shrubland. Nutrient concentrations in SLF did not differ significantly among land-use types, indicating that differences in SLF-associated N loss were mainly related to water volume. Targeted conversion of erosion-prone steep cropland to pastureland may therefore reduce surface runoff, sediment loss, and P export but should be combined with N management to limit soluble-N transport through shallow lateral pathways. These findings apply specifically to lateral soil water intercepted at 30 cm depth and should not be extrapolated to deep percolation or groundwater recharge.

Grasslands are widely recognized as important sinks of methane (CH4). However, their CH4 uptake capacity has been increasingly weakened driven by human activities and changes in precipitation regimes. In particular, the rapid expansion of livestock grazing can lead to substantial increases in CH4 emissions. For the Eurasian grasslands that have been subject to long-term grazing, how well they currently function and will continue to function as CH4 sinks under the changing precipitation regimes remains uncertain. Here we conducted an 11-year grazing-gradient experiment to assess the combined effects of grazing intensity and precipitation variability on grassland CH4 fluxes. We measured soil CH4 uptake in a manipulative grazing experiment in both wet and dry years, estimated livestock-derived CH4 emissions, and examined a range of biotic and abiotic drivers, including vegetation attributes, soil properties, and microbial biomass, for short- (prior to the onset of the lagged response) and long-term (the entire experimental period) influences on the dynamics of CH4 uptake in temperate meadow grasslands. Over the long term, CH4 fluxes are jointly regulated by precipitation and grazing, with overgrazing amplifying the suppressive effect of rainfall on CH4 uptake. Soil CH4 uptake showed a lagged response to grazing, which may have been triggered by extreme rainfall events. While moderate grazing sustained the long-term CH4 uptake, it fails to offset livestock-derived CH4 emissions. In the short term, CH4 fluxes are primarily governed by grazing, whereas in the long term they are jointly regulated by precipitation and grazing intensity. These results offer a new perspective for understanding the source-sink CH4 dynamics of grasslands in the context of ongoing climate change.

Agricultural ecosystems face the persistent threat of soil acidification resulting from long-term chemical fertilizer application; however, the dynamics of microbial communities and carbon (C), nitrogen (N), and phosphorus (P) cycling functions under varying acidification levels remain unclear. In this study, we employed a meta-analysis of 821 observations from 121 peer-reviewed articles to investigate the responses of farmland soil microbial communities to varying acidification levels. Our results revealed significant variations in soil microbial composition, diversity, and function in response to acidification. As soil pH decreased, bacterial and fungal diversity exhibited divergent trends. Specifically, compared to neutral pH, bacterial Shannon diversity declined significantly by 50.67 %, while Chao1 diversity increased by 29.19 % at pH 3.5-4.5 (p < 0.05). The abundances of Zygomycota, Acidobacteria, Gemmatimonadetes, Actinobacteriota, and Verrucomicrobia showed the strongest correlations with soil acidification. Functionally, acidification suppressed C degradation and methane metabolism, enhanced N degradation and nitrification while reducing multiple nitrate-reduction pathways, and stimulated phosphate acquisition, solubilization, and mineralization. Partial least squares path modeling (PLS-PM) analysis indicated that soil acidification had significant negative effects on soil C, N, and P nutrient availability, bacterial alpha diversity, and C and N cycling functions. This study employed a meta-analysis approach to analyze changes in microbial diversity and function across varying degrees of acidification, providing strategies for managing acidified farmland soils.

Soil acidification disrupts microbial ecosystems and increases crop susceptibility to bacterial wilt, posing a significant threat to global agricultural sustainability. While its influence on Ralstonia solanacearum-induced bacterial wilt has been documented, studies report inconsistent effects on disease incidence, severity, and pathogen abundance, with the interactive roles of environmental and edaphic factors remaining poorly understood. To resolve these discrepancies, we conducted a comprehensive meta-analysis of 317 studies across Asia, Africa, Americas, covering major Ralstonia-host crops (tomato, potato, tobacco, peanut and sesame) . Our results demonstrated that soil acidification significantly increased bacterial wilt incidence (1.93-fold), disease severity (1.88-fold), and R. solanacearum abundance (1.33-fold). Key moderators included precipitation and temperature which attenuated disease severity at higher levels, and soil available phosphorus, which showed strong negative correlations with both disease incidence (r = −0.40) and pathogen abundance (r = −0.68). These findings suggest two actionable management strategies to reduce bacterial wilt risk: (1) maintaining optimal soil pH ( > 6.5) and (2) targeted phosphorus fertilization to counter acidification-driven pathogen proliferation. By elucidating soil chemistry-environmental-pathogen interactions, this study provides a robust foundation for sustainable soil health strategies and bacterial wilt mitigation.

CONTEXT: Climate change is projected to threaten food security and stimulate greenhouse gas emissions. Hence, adaptation measures without sacrificing food production are required. OBJECTIVE: To assess possible consequences of rice-wheat system under climate change and to propose possible practices for mitigation. METHODS: The Soil-Plant-Atmosphere Continuum SYStem (SPACSYS) model was tested using datasets from long-term experiment (1991-2019) assessing the impact of different fertilisation on crop production, crop nitrogen (N) content, soil organic carbon (SOC) stock, methane (CH4) and nitrous oxide (N2O) emissions in a Cambisol under rice-wheat system. The validated SPACSYS was then used to investigate the possible mitigation strategies from 2024 to 2100 under climate change scenarios (SSP1-2.6 and SSP5-8.5) and the baseline scenario and mitigation management scenarios, i.e., (i) reduced N application rate by 20 % (RNA), (ii) the introduction of mid-season drainage (MSD) and (iii) integrated management combining RNA with MSD (IM). RESULTS AND CONCLUSIONS: Results showed that SPACSYS performed effectively in simulating yield and N content in grain and straw, SOC stock and CH4 and N2O emissions. Scenarios analysis elucidated that RNA would not decrease grain yields for either rice or wheat under the two climate change scenarios. Compared to the baseline scenario, low level of climate change scenario considering the CO2 fertilisation effects (SSP1-2.6_CO2) may benefit wheat yield (28 %) and had no effects on rice yield. In contrast, under the SSP5-8.5 scenario, whether CO2 fertilisation effects are considered or not, both rice and wheat yield could face great loss (i.e., 11.8-29.9 % for rice, 8.3-19.4 % for wheat). The winter wheat would not be suitable for planting in the distant future (2070-2100) due to the incomplete vernalisation caused by warming. The switching from winter wheat to spring wheat from 2070 onward could avoid the yield loss by 8.3-19.4 %. Climate change could decrease SOC sequestration rate. Under future climate change scenarios, IM could significantly decrease CH4 emissions by 56 % and N2O emissions by 24 %, as such reducing the net global warming potential by 69 % compared to no adaptation. Our simulations suggest that under climate change, crop switching in rice-wheat system combining integrated mitigation practices is possible to mitigate global warming and maintain crop production.

The sensitivity of model outputs to parameter variations is crucial for effective model calibration and application. This study assessed the sensitivity of N2O and CH4 emissions to varying weather conditions and fertilization practices in a winter wheat–rice cropping system. Using the Sobol first-order sensitivity index within the SPACSYS model, key parameters and input variables influencing gas emissions were identified. The results showed that the index effectively detected highly sensitive parameters, particularly those related to soil water content, oxygen dynamics and microbial processes. Both N2O and CH4 emissions were sensitive to carbon availability and soil oxygen levels. For N2O emissions, microbial process parameters and soil water content had substantial impacts, whereas CH4 emissions were more responsive to methane consumption, oxygen levels, and carbon substrates. Fertilization, rainfall and temperature showed high sensitivity for N2O emissions, while temperature emerged as the dominant factor controlling CH4 emissions. The identified parameters offer valuable insights for improving model performance and informing strategies to mitigate greenhouse gas emissions.

Context: Global food production is facing severe challenges due to climate change. Previous climate-crop modeling studies have developed multiple adaptation strategies, such as adjusting sowing dates, densities, and optimizing cultivars, to counteract the negative impacts of climate change. In northwest China, plastic mulching (PM) is extensively utilized to alleviate drought stress, improving both yield and water use efficiency (WUE). Nonetheless, the integration of PM with prevalent agricultural practices to formulate a comprehensive strategy for adapting to climate change has not been investigated. Objective: We aim to integrate different virtual cultivars, sowing dates, and plant densities with PM practices to identify the most effective strategies for enhancing yield and WUE under climate change. Methods: The simulation of maize yield and WUE under adaptive conditions was conducted using the SPACSYS (Soil-Plant-Atmosphere Continuum System) model. The model was calibrated and validated with five-year field observation data at Yangling in northwest China. It was driven by climate data projected from one Global Climate Model identified as representing the worst-case scenario from the Coupled Model Intercomparison Project phase 6 for the study site. The simulations were based on a high emission scenario of future societal development pathway (SSP585) during two periods (2021-2060 and 2061-2100). Results: Our simulation results show that future maize yield without adaptation was projected to decrease by 4.3 % in the 2040s (2021-2060) and 56.0 % in the 2080s (2061-2100). We found that postponing sowing dates by 15 days and increasing plant density to 7.5-9 plants m -2 can boost yield and WUE in future climate scenarios. Furthermore, when PM was integrated with optimal virtual cultivar under optimal planting date and density, the simulated yield rose by 97.6 % and 25.5 % in the 2040s and 2080s, respectively, relative to the reference management, while WUE rose by 162 % and 114 %, respectively. Conclusions: Integrating PM with delayed sowing and higher planting densities can enhance maize yield and WUE under future climates. An optimal climate-adapted maize cultivar should have longer growth durations, higher specific leaf area, and improved carbohydrate transfer rates than current cultivars. These results underscore the significant potential of combining optimal genotype and agronomic options to enhance yield and WUE under climate change in arid rainfed regions. Significance: This research offers valuable insights for breeders and agronomists in formulating genotype x management strategies to cope with climate change.

Context: Plastic film mulching (PM) is a widely adopted technique for enhancing crop yield in arid and semiarid regions. However, the improved soil hydrothermal conditions under PM may accelerate the mineralization of soil organic carbon (SOC) and increase greenhouse gas (GHG) emissions. Concurrently, crop stubble return, while widely recognized for its benefits in improving soil properties and mitigating GHG emissions, has demonstrated inconsistent effects on crop yield. Given the individual advantages of these practices, their combined application may offer a sustainable agricultural approach to achieving high yields and low GHG emissions. It is important to investigate the long-term combined effects of stubble return and PM on SOC dynamics, crop productivity, and GHG emissions under future climate change scenarios. Objective: We aim to investigate the novel synergy of PM combined with stubble return as a strategy to achieve high yield and environmental sustainability under future climate change. Methods: The SPACSYS model was calibrated using seven years of field trial data to evaluate its precision in simulating yield, SOC dynamics, and GHG emissions in Yangling, northwest China. Our simulations utilized an ensemble of 27 global climate models across two emission scenarios (SSP245 and SSP585) from Coupled Model Intercomparison Project Phase 6 to drive the model. We explored multiple agronomic strategies, including 11 stubble return levels (from 0 % to 100 % in 10 % increments) and two mulching practices (no mulching and PM), to identify the optimal management practice under future climate change. Results: The yields of the reference management (CK, without mulching and stubble return) are projected to decline by 20.3 % and 60.0 % under SSP245 and SSP585, respectively, during the 2080 s (2061-2100), compared to the baseline period (1981-2020). Additionally, SOC under the CK is expected to decrease by 23.6-29.7 % in the 2040 s and by 43.0-58.1 % in the 2080 s. An optimal scenario involving 100 % stubble return with PM (PM_R100) increases yields in the 2040 s and mitigates yield losses in the 2080 s under SSP585, compared to CK during the baseline. Furthermore, PM_R100 leads to an increase of 11.1-23.6 % in SOC during the 2040 s and alleviates SOC decomposition in the 2080 s under SSP585. PM_R100 also reduces global warming potential (GWP) compared to CK, transforming the dryland maize system into a carbon sink in the 2040 s. Conclusions: PM combined with 100 % stubble return is the optimal practice to increase yield and SOC stock while reducing GWP. This approach effectively ensures high yields and promotes sustainable agriculture under climate change. Significance: Our study underscores the significance of adopting stubble return practices in dryland rainfed areas where PM is applied. Our results are anticipated to assist farmers and policymakers in formulating effective mitigation and adaptation strategies to promote low-carbon sustainable agricultural development in dryland maize-growing regions under climate change.

Livestock grazing can strongly determine how grasslands function and their role in the carbon cycle. However, how ecosystem carbon exchange responds to grazing and the underlying mechanisms remain unclear. We measured ecosystem carbon fluxes to explore the changes in carbon exchange and their driving mechanisms under different grazing intensities (CK, control; HG, heavy grazing; LG, light grazing; MG, moderate grazing) based on a 16-year long-term grazing experimental platform in a desert steppe. We found that grazing intensity influenced aboveground biomass during the peak growing season, primarily by decreasing shrubs and semi-shrubs and perennial forbs. Furthermore, grazing decreased net ecosystem carbon exchange by decreasing aboveground biomass, especially the functional group of shrubs and semi-shrubs. At the same time, we found that belowground biomass and soil ammonium nitrogen were the driving factors of soil respiration in grazed systems. Our study indicates that shrubs and semi-shrubs are important factors in regulating ecosystem carbon exchange under grazing disturbance in the desert steppe, whereas belowground biomass and soil available nitrogen are important factors regulating soil respiration under grazing disturbance in the desert steppe; this results provide deeper insights for understanding how grazing moderates the relationships between soil nutrients, plant biomass, and ecosystem CO2 exchange, which provide a theoretical basis for further grazing management.

Livestock feeding behavior and intake play a crucial role in influencing grassland health and productivity. A comprehensive investigation into livestock feeding behavior and intake can effectively elucidate the interactions and impacts of livestock and grasslands, providing scientific evidence and technical support for the formulation and implementation of sustainable grassland development strategies. Based on a long-term controlled grazing experiment platform conducted over 13 years, the feeding behavior and forage intake of cattle under different grazing intensities were observed and analyzed. Additionally, we used GPS sensors to study cattle grazing behavior trends. Using Mantel's test, we analyzed the relationship between cattle movement distance, forage intake, and environmental factors. The results demonstrated that cattle forage intake decreased with increasing grazing intensity. Forage intake peaked at the end of July and beginning of August, with the highest efficiency observed in August. Moreover, under light grazing intensity, cattle exhibited greater fluctuations in forage intake than those under moderate and heavy grazing intensity. Cattle movement levels increased with higher grazing intensity, and during the period of lush grass growth, cattle displayed significantly higher movement levels than during grass senescence. The accuracy of the behavior determination model based on cattle velocity ranged from 60 to 80 %. Using this model, we found that under heavy grazing conditions, cattle spent significantly more time roaming than under light and moderate grazing. Conversely, under light grazing conditions, cattle spent significantly more time feeding. A negative correlation was identified between cattle forage intake and movement distance. Cattle's forage intake was significantly positively correlated with grass height and grass biomass and significantly negatively correlated with stocking rate and movement distance. Thorough research on live-stock feeding behavior and intake offers scientific evidence and technical support for formulating and implementing sustainable grassland development strategies.

The effects of grazing on the cycling of carbon (C), nitrogen (N) and phosphorus (P) in grassland ecosystems are complex. Uncertainty still exists as regards the allocation of C, N and P storage amounts in grazed ecosystems in Inner Mongolia, situated at the eastern end of the Eurasian dryland. Based on the long-term cattle grazing experimental platform in the Hulun Buir meadow steppe of Inner Mongolia, a 3-year (2019-2021) field control experiment was conducted to assess how the grazing intensity influenced the quantities of C, N and P stored in canopy biomass, root, litter and soil compartments. We examined the relationships between the different pools and their regulatory pathways at the ecosystem level across six grazing intensities. In general, grazing increased the aboveground N and P contents but decreased the aboveground biomass C content and nutrient storage amounts in aboveground biomass, roots and litter. The grazing intensity of 0.34 AU ha-1 increased soil organic carbon, total nitrogen and total phosphorus storage amounts, with the soil accounting for 98 % of total reserves on average. Grazing affected soil pH， nutrient contents, above- and belowground biomass and soil environmental factors such as soil bulk density, which in turn affected C, N and P storage in the ecosystem according to the results of the structural equation model; therefore, grazing intensity can be an important factor regulating the input and output of nutrients in the ecosystem. In the future, for adaptive management of grasslands, moderate grazing could effectively increase C, N and P storage in meadow steppe ecosystems and ensure the nutrient balance and long-term sustainable development.

Understanding dynamics of soil organic carbon (SOC) stock in agroecosystems under climate change is imperative for maintaining soil productivity and offsetting greenhouse gas emissions. Simulations with the SPACSYS model were conducted to assess the effects of future climate scenarios (RCP2.6, RCP4.5 and RCP8.5) and fertilisation practices on crop yield and SOC stock by 2100 for a continuous winter wheat cropping system in southeast England. Weather data between 1921 and 2000 was considered as the baseline. SPACSYS was first calibrated and validated with the data of the Broadbalk continuous winter wheat experiment for over a century. Six treatments were used: no fertiliser, a combination of chemical nitrogen, phosphorus and potassium with three nitrogen application rates (N1PK, N3PK and N5PK), manure only (FYM, close N application rate to N5PK) and a combination of manure and chemical nitrogen application (FYMN, the same chemical N application rate as N3PK). Compared with the observations, SPACSYS was able to simulate grain yields and dynamics of SOC and TN stocks. Our predications showed that wheat yield would increase by 5.8–13.5% for all the fertiliser application treatments under future climate scenarios compared to that under the baseline because of a gradual increase in atmospheric CO2 concentration. Meanwhile, the SOC stock can increase for the practices under the scenarios except the NPK fertiliser practices under RCP2.6. Increased C input through “CO2-fertilisation effects” can compensate C losses by soil respiration under the RCP scenarios. We concluded that manure application practices can be considered as a sustainable strategy for enhancing wheat yield and soil C sequestration under the future climate scenarios.

Straw retention has been widely implemented to increase soil organic carbon (SOC) sequestration and green-house gas (GHG) mitigation for global agriculture. However, the combined effects of long-term straw retention on crop production, SOC sequestration and GHG emissions response to climate change remain unknown. Two nearby wheat-maize rotation field experiments in the North China Plain, combined with local weather, soil and agronomic measurements, were used to evaluate the applicability of the SPACSYS model. The model was then applied to assess the response of crop yield, SOC storage and nitrous oxide (N2O) emissions to three nitrogen fertilizer application levels (100, 200, 400 kg N ha(-1)) and three representative concentration pathway scenarios (RCP2.6, RCP4.5 and RCP8.5) under straw retention for the wheat-maize rotation systems during 2021-2100. In general, the model was reasonably accurate with R-2 and model efficiency (EF) ranging from 0.25 to 0.96 and 0.32-0.94, respectively. Climate change decreased wheat yield by 4-39%, while maize showed a slight increase (3%) under RCP2.6 and a decrease of 1-15% under RCP4.5 and RCP8.5. The SOC storage in the 0-20 cm soil increased at a rate of 73-195 kg C ha(-1) yr(-1) but decreased within the upper 1 m soil at 280-390 kg C ha(-1) yr(-1). Climate change reduced the positive effect of SOC sequestration except in RCP2.6 and stimulated substantial N2O emissions ranging from 1-7.5 to 2.9-23.2 kg N ha(-1) yr(-1), consequently, the global warming potential increased from -79-2555 to 548-9357 kg CO2-eq ha(-1) yr(-1) under various N fertilizer application levels. This study reveals that the negative feedback under climate change with modelling approach, and extensive efforts are needed to make adaptations to ensure food production and reduce GHG emissions in the future.

Rice production in the Yangtze River Basin accounts for 44.4 % of China's total rice production. Exploring the response of crop yields to soil organic carbon (SOC) storage under various fertilisation treatments for maintaining high and sustainable crop yields is an urgent issue. A database containing information on crop yields, SOC content, environmental factors (climate and soil properties), and nutrient input from fertilisation was established from seven long-term experimental sites located in the middle and lower reaches of the Yangtze River Basin (operational since the 1980s/1990s) in two lowland rice-based cropping systems (i.e., rice-wheat rotation and rice-rice rotation systems). The study considered four treatments: no fertiliser application (CK); application of chemical nitrogen, phosphorus, and potassium fertilisers (NPK); application of manure (M); and a combination of NPK and M (NPKM). Results showed that the NPKM treatment produced the highest crop yields, followed by the NPK/M and CK treatments. The NPK and NPKM treatments generally had higher sustainable yield indices (SYI, 0.34-0.74) and lower coefficients of variation (CV, 11-32 %) than the M and CK treatments (SYI: 0.29-0.62 and CV: 15-44 %) in both cropping systems across all sites. Crop grain yields were significantly increased with increasing SOC storage (0-20 cm) and followed a logarithmic regression in both systems, suggesting that a further increase in SOC content could lead to higher yields. Structural equation modelling indicated that fertilisation, soil properties, and climate together explained 75-77 % of the variance in crop yield in the two systems. The primary contributing factors were fertilisation and its associated changes in soil nutrients. Chemical fertilisers mainly had direct effects on crop yields, while manure had both direct and indirect (through improvements in soil properties) effects on crop yields. In the rice-rice system, SOC alone had both direct and indirect (through the improved availability of soil nutrients) positive effects on crop yields. Our findings emphasise the potential benefits of sequestering SOC not only for enhancing crop production but also for improving the stability and sustainability of crop yield from paddy fields.

With a growing body of research associating livestock agriculture with faster global warming, higher health costs and greater land requirements, a drastic shift towards plant-based diets is often suggested as an effective all-round solution. Implicitly, this argument is predicated on the assumption that the reallocation of resources currently assigned to animal production systems will automatically result in the efficient cultivation of human-edible crops without negative environmental, health or socioeconomic consequences. In reality, however, the validity of this assumption warrants careful examination, as a farm’s capability to adopt a new agricultural system is multifaceted and context-specific. Through a transdisciplinary review of literature, here we discuss examples of unintended consequences that could arise from the conversion of grasslands into arable production, including potentially adverse impacts on yield stability, biodiversity, soil fertility and beyond. We contend that few of these issues are being methodically considered as part of the current food security debate and call for a closer examination of supply-side constraints.

The widespread adoption of returning crop residue to regulate soil properties and improve yields has been well established. However, the long-term effects of residue return on soil organic carbon (SOC) and yield in film mulched farmland, especially under future climate conditions, are still unclear. To address this issue, we utilized the SPACSYS model, which was calibrated with 5-year (2016-2020) field experiment data from various mulching and fertilization treatments in the Hetao irrigation district in northwest China. Furthermore, we investigated the impacts of climate change on SOC storage in 20 cm and maize yield with calibrated SPACSYS model driven by 27 global climate models under two climate scenarios (SSP245 and SSP585) from CMIP6. We considered multiple combinations of agronomic options: five residue return levels (R1: 20%; R2: 40%; R3: 60%; R4: 80%; R5: 100%) and three return depths (D1: surface applied; D2: 10 cm; D3: 20 cm) to evaluate the effects of residue return on SOC storage and yield. We found that yield at a high fertilization rate with transparent film mulching (HT) would increase by 10.1% under SSP245, 15.3% under SSP585 in 2021-2060 compared to the baseline (1981-2020). By contrast, the yield would decrease by 5.8% under SSP245, 21.7% under SSP585 in 2061-2100. SOC storage under HT would decrease by 9.4-12.7% and 18.4-41.4% in 2021-2060 and 2061-2100, respectively. We determined that the optimal treatment involves returning 100% of residue to a depth of 20 cm (R5D3). Under R5D3, yield showed an increasing trend in both two future periods; the SOC storage decreased by 4.8-6.8% in 2021-2060 and increased by 3.9-16.1% in 2061-2100 compared to the baseline under HT. Our results highlight the potential of residue return to increase yield while maintaining soil health when film mulching is adopted.

For mitigating the unintended environmental impacts associated with intensive farming across the world, it is crucial to understand the complex impacts of potential reductions in fertiliser use on multiple ecosystem services, including crop production, GHG emissions and changes in soil organic carbon (SOC) stocks. Using site specific spatial data and information, a novel integrated modelling approach using established agroecosystem models (SPACSYS and RothC) was implemented to evaluate the impacts of various fertiliser reductions (10%, 30% and 50%) under current / baseline and projected (RCP2.6, RCP4.5 and RCP8.5) climate scenarios in a study catchment in southwest England. 48 unique combinations of soil types, climate conditions and fertiliser inputs were evaluated for five major arable crops (winter wheat, maize, winter barley, spring barley, winter oilseed rape) plus ryegrass. Modelled annual estimates of crop yields and biomass, emissions of gases with warming potentials (nitrous oxide, methane, carbon) and SOC stocks in the topsoil (0-30 cm) were tabulated for all combinations considered. These simulated data series could be further analysed to evaluate inter-annual variations and their implications for climate resilience and combined with additional data to quantify nutrient use efficiency and undertake cost- benefit analysis, and to contribute to inter-regional comparisons of fertiliser management at broad scale.

Plastic film mulching (PM) combined with irrigation is widely adopted to improve crop yields, water and nitrogen efficiency, especially in arid farming areas. Despite its benefits, the effects of this method on soil quality and its subsequent impact on crop productivity and resource efficiency have not been thoroughly investigated. In this study, we formulated a soil quality indicator (SQI) from five years of field experiments in the Hetao Irrigation District (HID) of Northwestern China. The treatments included border irrigation as the control treatment (CK), CK combined with PM (BI_PM), and three water level drip irrigation treatments combined with PM. Three threshold values of soil matric potential for drip irrigation were -10 kPa (HDI_PM), -30 kPa (MDI_PM), and -50 kPa (LDI_PM). We then examined the SQI changes based on measured multiple soil properties and assessed their implications for maize yield, irrigation water productivity (IWP), and partial factor productivity of nitrogen (PFPN). We found: (1) from 2016 to 2020, HDI_PM achieved the highest average yield (15.77 t ha(-1)), IWP (3.73 kg m(-3)), and PFPN (63.18 kg kg(-1)), showing increases of 54.77 %, 84.90 %, and 96.93 % over the control treatment, respectively; (2) no significant variations in the SQI were observed for HDI_PM in 2020 in the topsoil (0-30 cm) and subsoil (30-60 cm) compared to the initial condition. However, CK, BI_PM, MDI_PM, and LDI_PM showed reductions in SQI in both soil layers, primarily due to decreased soil organic carbon (SOC) and structural stability, along with increased sand content and soil salinity; (3) according to the linear mixed-effects model, a low SQI (< 0.43), elevated temperatures, and drought indices negatively impact yield. Hence, we advocate for HDI_PM to maximize yield and PFPN. To enhance soil quality, identifying agronomic practices that increase SOC and reduce soil salinity in the HID is crucial.

CONTEXT: The Stipa breviflora desert steppe ecosystem is fragile and sensitive to climate change and grazing disturbance. Previous studies have reported the effects of climate change and grazing on aboveground standing biomass of the plant community and sheep live weight, however, the interaction between climate change and grazing remains unclear. Process models have become ideal tools for the evaluation of the effects of grazing management practices under climate change. OBJECTIVE: We used the Soil-Plant-Atmosphere Continuum System (SPACSYS) model to investigate aboveground standing biomass and the live weight of sheep in the desert steppe of Inner Mongolia under future climate change scenarios and different grazing management. The results will be used to inform adaptive management strategies. METHODS: The grazing experiment consisted of four treatments: no grazing (0 sheep ha- 1 half year- 1), light stocking rate (0.91 sheep ha- 1 half year- 1), moderate stocking rate (1.82 sheep ha- 1 half year- 1), and high stocking rate (2.71 sheep ha- 1 half year- 1). We used observed data on soil temperature, soil volumetric water content, changes to sheep live weight, and aboveground standing biomass of plant community to provide parameterization and validation for the SPACSYS model. We then predicted aboveground standing biomass of the plant community and sheep live weight changes for different grazing management under three representative concentration pathways (RCP) scenarios (RCP 2.6, RCP 4.5, and RCP 8.5) from 2021 to 2100. RESULTS AND CONCLUSIONS: Moderate and high stocking rates decreased aboveground standing biomass and sheep live weight changes more than the light stocking rate. A light stocking rate can maintain higher aboveground standing biomass and sheep live weight as well as meet production requirements. Therefore, a light stocking rate is a potentially effective management approach to improve food production security and combat global climate change in the desert steppe. SIGNIFICANCE: The model can inform management strategies for grazing in the desert steppe under climate change, supporting efforts to maintain the stability of the steppe ecosystem and increase economic benefits, while also providing a theoretical basis for adaptive management in the desert steppe.