Context: Cereal-legume intercropping improves water use efficiency (WUE) in dryland agriculture. Yet, how intercrops and soil water interactions drive productivity is poorly understood, particularly under fluctuating rainfall conditions. Objective: The study aims to analyze the spatiotemporal dynamics of soil water, elucidate mechanisms behind water productivity gains, and identify the role of plastic film mulching in maize-soybean intercropping. Methods: A two-year rainfed field experiment (dry 2017 and wet 2018) compared two intercropping systems (maize-soybean intercropping with maize film mulching (FMS) and without mulching (NMS)) with their respective monocultures. Measurements included water equivalent ratio (WER), net effect on WUE (Delta WUE), soil moisture, yield, grain yield and dry matter. Results: The WER values (1.20-1.28) confirmed that both FMS and NMS systems improved water productivity compared to respective sole cropping. This advantage arose from the synergy between interspecific water competition and spatiotemporal niche complementarity, which created a contrasting soil moisture gradient between maize and soybean strips. The gradient facilitated much more grains formation of both crops in intercropping, due to supplying adequate water for maize during silking and grain filling while providing reduced but sufficient water for soybean during flowering. Thereby, it matched intercrops' physiological needs for high yield (maize grain of 14.91 Mg ha(-1) and soybean grain of 1.79 Mg ha(-1)). Moreover, FMS increased intercropping Delta WUE by 77.4%, mainly by boosting maize dry matter and supporting grain yield increase by 9.8% (P < 0.05). It shifted water allocation between intercrops, strengthening maize's competitive edge in dry years and enhancing system-wide water conservation in wet years. It also improved soil water storage for reproductive growth and promoted preferential use of topsoil water, indicating a sustainable strategy for dryland farming. Conclusions: Maize-soybean intercropping boosts water productivity via complementary water-use strategies, and film mulching further enhances system productivity and climate resilience in dryland agriculture. Significance: This work links technology with eco-physiological mechanisms to explain WUE in intercropping, offering practical strategies for sustainable food production under water scarcity and climate variability.

Film mulching and gravel mulching are effective methods for increasing crop yields in Northwest China but exacerbate soil organic carbon (SOC) mineralisation. Manure amendment is a viable method for offsetting carbon (C) losses from mulching. SOC stability is a key factor in determining the nutrient supply capacity of soils, as it affects the C sources available to microorganisms. However, the synergistic effects of film mulching and manure amendment on SOC stability and crop nutrient uptake are still unclear. Therefore, four treatments—no mulching (CK), gravel mulching (GM), film mulching (FM), and film mulching with manure amendment (FCM)—were established on the Loess Plateau. Experiments were conducted to measure plant and grain nitrogen (N), phosphorus (P), potassium (K) uptake, SOC, labile organic C fractions (LOCFs), stability-based organic C fractions (SOCFs), and the C management index (CMI) in 2019 and 2020. The results showed that the FM and FCM treatments significantly improved crop dry matter accumulation in both years compared to the control. The FCM treatment significantly increased the two-year NPK averages of plants to 44.9%, 50.7%, and 54.5% and significantly increased those of grains to 46.7%, 58.2%, and 30.4%. The FCM treatment significantly increased all LOCFs, water solution C (WSC), hot-water-extractable C (HWC), permanganate oxidisable C (POXC), and particulate organic C (POC) in the topsoil (0–20 cm) in both years. The fractions of the active C pool (AP) in the SOCFs, namely, very labile C (CVL) and labile C (CL), were significantly increased, suggesting that the FCM treatment significantly decreased C stability in the topsoil. The sensitivity index showed that, among all SOC fractions, POC (21.5–72.9%) and less labile C (CLL) (20.8–483.8%) were the most sensitive fractions of LOCFs and SOCFs compared to SOC (1.93–35.8%). A random forest analysis showed that most labile C fractions and the CMI significantly contributed to crop N, P, and K uptake, especially POXC to crop N uptake, the CMI to crop P uptake, and the AP to crop K uptake. It was concluded that the FCM treatment synergistically enhanced SOC lability, crop NPK uptake, and labile C fractions, especially POXC, the AP, and the CMI, which serve as robust indicators for guiding precision nutrient management in semi-arid croplands.

Water footprint (WF) is a water sustainable management indicator that quantifies the virtual water use in crop production. Water productivity (WP) and WF were examined under different tillage practices for wheat (Triti-cumaestivum L.) in the semiarid Loess Plateau of China. Wheat was grown in 2002-2017 with six tillage practices: conventional tillage (T), no-till without straw cover (NT), conventional tillage with straw cover (TS), no-till with straw cover (NTS), conventional tillage with plastic mulching (TP), no-till with plastic mulching (NTP). Tillage practices did not significantly increase crop evapotranspiration, but NTS, TP, and NTP reduced soil evaporationwhile increasing transpiration, root growth and biomass accumulation. Additionally, NTS reduced the water consumption during the early stage but increased the water utilization from heading to harvest, while TP, and NTP exhibited the opposite pattern. Wheat yield under TS, NTS, TP, and NTP was higher by13, 28, 22, and 24 %, respectively, than under T, with corresponding improvements in water productivity of 15, 24, 26, and 24 %, respectively. The change in net economic return was 39, 21, 148,-49, and 18 % for NT, TS, NTS, TP, and NTP, respectively, compared to T; the sustainability yield index was 0.45, 0.41, 0.52, 0.55, 0.48 and 0.47, respectively. Total water consumption was significantly increased by 8.2 and 9.8 % under TS and NTS, respectively, compared to T. WF under NTS, TP and NTP was significantly decreased by 18.6, 18.5 and 22.3 % compared to T, respectively. These results suggests that NTS increased yield, economic benefits and WP with less WF through enhancing root growth and water utilization during the filling period. Therefore, NTS represented a sustainable a sustainable water management strategy for wheat in the semiarid Loess Plateau.

Maize is a critical grain crop in China, having the largest planting area and highest total yield of all grain crops. In the four-primary maize-producing regions of China (Northeast, North China Plain, Northwest and Southwest), persistent regional production challenges and yield-limiting factors have impeded the realization of efficient maize production. This paper reviews sustainable, yield-enhancing and efficiency-improving practices for maize production in China. By addressing the regional constraints in major maize-producing areas and incorporating strategies, such as high-yield population construction, the establishment of appropriate tillage layers and soil fertility enhancement through precise matching technologies, this study integrates regionalized integrated fertilizer application and a government-enterprise-university-research-application collaborative model, focusing on the Science and Technology Backyards. The goal is to facilitate sustainable, efficient, scaled and modernized development across diverse maize-growing regions in China. This approach is expected to provide a foundation for sustainable and efficient maize production in China.

The efficiency of water use in irrigated agriculture is a global priority to address water scarcity. A comprehensive meta-analysis was conducted to evaluate the effects of irrigation practices on potato yield, crop evapotranspiration (ETc), water productivity (WP), and irrigation water productivity (IWP) across diverse growing conditions, including soil texture, fertilizer application rates, annual precipitation, and soil organic carbon (SOC). The results revealed that supplementary irrigation increased potato yield by 55% and ETc by 39% while maintaining WP comparable to non-irrigated conditions. The greatest yield and WP improvements from supplementary irrigation occurred under drip irrigation with moderate N, P, and K application rates (150–250 kg ha−1) and irrigation amounts below 150 mm. This practice was particularly effective in sandy soils with 1.5–2.0% SOC and annual rainfall of 200–400 mm. Conversely, deficit irrigation reduced potato yield and ETc by 25% and 24%, respectively, but significantly enhanced WP and IWP by 9% and 28% compared to full irrigation. When a water-saving ratio of 10–20% was implemented under drip irrigation with optimal fertilizer rates (240–360 kg N ha−1, >104 kg P2O5 ha−1, 150–200 kg K2O ha−1), deficit irrigation improved WP without yield loss in sandy soils with annual rainfall of 600–800 mm when compared to full irrigation. The IWP increased with rising SOC levels, indicating that SOC improvement in low-carbon soils enhances water productivity in irrigated potato systems. These findings demonstrate that tailored irrigation strategies can simultaneously reduce water inputs and achieve higher yield and WP in potato production systems.

Exogenous organic matter input into the soil may either expedite or postpone the soil organic matter decomposition, resulting in a beneficial or detrimental "priming effect" (PE), in which soil microbes have a crucial function. Notably, a succession of fungal communities were detected during PE, indicating that fungi play a substantial role in influencing PE. However, the assembly processes that shape fungal community composition during PE require further investigation. We conducted residue decomposition experiments by adding C4 maize straw (natural 13C-labelling substrates) to C3 soil (13C non-enriched) that was amended for 120 days (d) to investigate the PEs dynamics associated with the succession of fungi detected by high-throughput sequencing techniques. Our outcomes demonstrated that during the initial 10 d of incubation, the addition of residue resulted in negative PE, regardless of whether N was applied or not. However, a positive PE was observed after 30 d. Nitrogen alone increased total CO2 emissions of soil compared to the control throughout the incubation interval. The composition of the fungal community shifts from copiotrophic populations in the early stages to oligotrophic populations in the later stages during straw decomposition. Null model analyses revealed that deterministic processes (homogeneous selection) regulated fungal community composition across decomposition stages, whereas stochastic processes (homogeneous dispersal) increased with decomposition. The origin of carbon straw determines the assembly mechanisms that impact the makeup of fungal communities and, thereafter, the process of breakdown. Our findings suggested that the assembly processes might be associated with PE by modulating fungal community composition during straw decomposition, including a combination of stochastic and deterministic processes. A comprehensive perspective of the fungal community structure can deepen the understanding of PE under the straw amendment.

Converting crop straw into biochar incorporation is a promising solution to avoiding straw return's potential risk of elevated greenhouse gas (GHG) emissions that could compromise the benefits of carbon (C) sequestration. Hereby, we proposed the continuous biochar incorporation that produced with equal-straw amounts (BI) to substitute straw returns in cropland. Nevertheless, this solution lacks strong evidences and mechanistic supports in the effectiveness and potential of global warming mitigation. Therefore, in a dryland wheat-maize rotation system, we conducted a 5-year field experiment with continuous applications of BI, straw incorporation (SI) and no incorporation (CK) to comprehensively assess the net global warming potential (GWP) and unveil its underlying mechanisms. The results suggested that the net GWP of BI was -7703 kg CO2-eq ha(-1) yr(-1), decreased by 69.9 % compared with SI (P < 0.05). This substantial reduction was primarily driven by enhanced soil C sequestration and reduced GHG emissions. Specifically, SI increased CO2 and N2O emissions by 23.6 % and 18.9 % (P < 0.05), respectively, while BI increased CO2 emissions by 6.2 % and decreased N2O emissions by 11.2 % compared with CK (P < 0.05), which led to a four-times' advantage of GWP mitigation gap for BI over SI. Crucially, the effect gap increased with incorporation years though showing a threshold value. Meanwhile, BI, SI and CK enhanced soil C sequestration by 2230, 1409 and -40 kg C ha(-1) yr(-1), respectively, under total C inputs by 4175, 5827 and 2258 kg C ha(-1) yr(-1) (anthropogenic incorporation C (1602, 3404 and 0 kg C ha(-1) yr(-1)) + root-derived C (estimated by plant biomass)). BI showed the highest plant biomass by 34 Mg ha(-1) yr(-1) among treatments, contributing to the increase of root-derived C input in rotation system. All data indirectly proved root-derived C sequestration increased under BI. Overall, BI mitigated GWP bidirectionally through both reduced GHG emissions and efficient soil C sequestration. Importantly, GHG emissions reduction increased with incorporation years and the advantage of soil C sequestration over SI was critically depended on enhanced crop root-derived C sequestration. These findings supplement strong evidences for straw return optimization for climate warming mitigation, contributing to disseminating the application of equal-straw produced biochar in global croplands. This study raises our strategic awareness of biochar positive role in climate change mitigation, since that the solution is promising in yield improvement, GWP enduring inhibition, abundant raw materials and accessing conveniently, coupled with low economical-and environmental-cost of conversion technology in future.

Vegetable wastes in general do not compost well due to their high moisture content (MC) and low dry mass. To overcome these obstacles, in this study co-composting of Chinese cabbage wastes (CA) or celery wastes (CE) with corn stover and sheep manure was utilized to improve the composting performance, and the effects of the additives on microbiota during composting and microbial degradation of lignocellulose and synthesis of humic acid (HA) were investigated. The results showed that addition of 25 % corn stover or 40 % sheep manure increased hemicellulose, cellulose and lignin destruction by 24.6 %- 29.9 %, 5.5 %- 14.0 % and 8.3 %- 17.3 %, respectively, and produced 20.5 %- 48.9 % more humic acid (HA). LEfSe analysis found that addition of 25 % corn stover or 40 % sheep manure promoted growth of lignocellulose-degrading microorganisms alongside with the transformation of anaerobic fermentation into aerobic fermentation, and analyses of bacterial and fungal functions testified that the addition of corn stover or sheep manure increased microbial activities related to aerobic chemoheterotrophy, lignocellulosic degradation and activities of saprotroph at different stages. Mantel test showed total organic carbon (TOC), moisture content (MC) and EC were positively correlated to bacterial biomarker and fungal biomarker, which were also significantly correlated to HA. The addition of 25 % corn stover or 40 % sheep manure was very effective in ameliorating the aeration state and provide alternative carbon sources during composting to promote growth of lignocellulose-degrading microorganisms, which increased lignocellulose degradation and saprophytic activities to accelerate the synthesis of HA.

Optimizing nitrogen fertilizer and straw application is essential for sustainable agricultural development. However, the effects of variations and related factors associated with nitrogen fertilizer reduction combined with different straws on soil quality and greenhouse gas emissions remain unclear. Hence, a two-year field experiment was conducted to comprehensively assess the effects of nitrogen fertilizer application rate and different straws incorporation on maize growth, the soil quality index (SQI), direct global warming potential (GWPdirect) and carbon footprint (CF). The treatments included: no nitrogen fertilizer (CK), conventional nitrogen fertilizer 225 kg ha-1 (N225), 20 % reduction of conventional nitrogen fertilizer (N180), N180 with soybean straw incorporation-legume crop straw (SN180) and N180 with maize straw incorporation-gramineous crop straw (MN180). Results revealed that the N180 treatment produced comparable yield to that of the N225 treatment and significantly increased nitrogen agronomic efficiency (NAE) by 16.54 %-16.98 %; however, SOC content decreased by 0.12 g kg-1. Compared with N180, the SN180 treatment significantly increased the SQI by 9.20 % in 2022 and 10.76 % in 2023, and the MN180 treatment increased the SQI by 3.19 % in 2022 and 8.69 % in 2023, respectively. Although the SN180 and MN180 treatments had higher the GWPdirect by 92.60 %-95.31 % and 49.67 %-53.51 % than the N225 treatment, the greater SOC sequestration rate (0.54 and 0.37 Mg C ha-1 y-1) and lower N application rate in these treatments resulted in substantial decreases in the CF of 72.05 %-73.50 % and 48.81 %-49.42 %, respectively. Mantel tests and partial least squares path modeling (PLS-PM) revealed that the higher SQI and N2O emissions in the SN180 than MN180 treatment were driven mainly by higher Nmin (13.01 %- 19.88 %) and MBN (5.28 %-7.09 %) contents, and Pacq (3.11 %-14.82 %) enzyme activity. Overall, 20 % reduction of conventional nitrogen fertilizer with legume straw incorporation was more effective at improving soil quality and reducing environmental pollution, providing guidance for sustainable development in semiarid farmland ecosystems.

Exploring optimal mulching methods for maize production is critical to achieving a balance between maximizing yield and reducing negative environmental impacts in dryland agriculture. Therefore, a 3-yr field experiment was conducted to investigate the effects of three mulching methods-biodegradable plastic film mulching (BM), maize straw mulching (SM), and no mulching (NM)-on spring maize yield, greenhouse gas (GHGs) emissions (CO2, CH4, and N2O), soil factors, the net ecosystem GHG balance and greenhouse gas emission intensity (GHGI) on the Loess Plateau of China. The result showed indicated that CO2 and N2O are the primary sources of GHGs in dryland maize production. The yield of BM significantly increased 1.43-1.99 t ha-1 compared to NM, CO2 emissions (on average 32.83%) compared to the NM. And BM showed suitability for N2O emissions (3.7-11.2%). SM increased CO2 and N2O emissions (by 9.43-13.17% and 24.96-33.64%, respectively) compared to the NM. Structural equation model analysis showed that soil temperature was the most direct factor to affect GHGs. SM was the sink of net ecosystem GHGs, BM and NM were the source of net ecosystem GHGs. These results indicated that mulching emerges as a promising strategy for dryland agriculture. BM method can be used when the primary goal was to improve yield, while SM method is a better choice when the primary goal was to improve soil organic carbon sequestration and reduce net GHGs emissions. This study clarified the impacts of mulching methods on three GHGs emissions to provide information support for sustainable agriculture on the Loess Plateau.

Synthetic microbial communities (SynComs) play significant roles in soil health and sustainable agriculture. In this study, bacterial SynComs (SCBs) and fungal SynComs (SCFs) were constructed by selecting microbial species that could degrade the potato root exudates associated with continuous cropping obstacles. SCBs, SCFs, and SCB + SCF combinations were then inoculated into organic fertilizers (OFs, made from sheep manure) to produce three bio-organic fertilizers (BOFs), denoted by SBFs (BOFs of inoculated SCBs), SFFs (BOFs of inoculated SCFs), and SBFFs (BOFs of inoculated SCB + SCF combinations), respectively. The OF and three BOFs, with a chemical fertilizer (CK) as the control, were then used in pot experiments involving potato growth with soil from a 4-year continuous cropping field. Microbial diversity sequencing was used to investigate the colonization of SCBs and SCFs into the rhizosphere soil and the bulk soil, and their effects on soil microbial diversity were evaluated. Source Tracker analysis showed that SCBs increased bacterial colonization from the SBFs into the rhizosphere soil, but at a relatively low level of 1% of the total soil bacteria, while SCFs increased fungi colonization from the SFF into the bulk soil at a much higher level of 5–18% of the total soil fungi. In combination, SCB + SCF significantly increased fungi colonization from the SBFF into both the bulk soil and the rhizosphere soil. Overall, the soil fungi were more susceptible to the influence of the BOFs than the bacteria. In general, the application of BOFs did not significantly change the soil microbial alpha diversity. Correlation network analysis showed that key species of bacteria were stable in the soils of the different groups, especially in the rhizosphere soil, while the key species of fungi significantly changed among the different groups. LEfSe analysis showed that the application of BOFs activated some rare species, which were correlated with improvements in the function categories of the tolerance of stress, nitrogen fixation, and saprotroph functions. Mantel test analysis showed that the BOFs significantly affected soil physicochemical properties, influencing bacterial key species, and core bacteria, promoting potato growth. It was also noted that the presence of SynCom-inoculated BOFs may lead to a slight increase in plant pathogens, which needs to be considered in the optimization of SynCom applications to overcome continuous cropping obstacles in potato production.

Soil amendments facilitate the restoration of degraded soil fertility and vegetation productivity. Soil hydrological functions are crucial for assessing soil degradation and restoration in grassland ecosystems. However, the manner in which soil amendments drive changes in the hydrological properties of grassland ecosystems at different soil depths remains unclear. In this study, we conducted a five-year soil amendment experiment in a semi-arid grassland of the Loess Plateau to evaluate the impact of aluminum sulfate (AS) and biochar (BC), both individually and in combination, on the hydrological properties of soil profiles. The results showed that AS significantly increased saturated water-holding capacity (SWHC) by 19.04 %, field capacity (FC) by 27.39 %, soil water storage (SWS) by 1.57 %, and saturated hydraulic conductivity (Ks) by 19.03 % in the upper soil layer (0-40 cm). BC application increased SWHC by 20.09 %, FC by 17.56 %, SWS by 12.94 %, and Ks by 16.66 % in the 0-40 cm soil layers. The combined effects of AS and BC optimized the soil hydrological properties by increasing SWHC, FC, SWS, and Ks by 25.74 %, 35.45 %, 18.47 %, and 25.80 %, respectively. These improvements were driven by significant changes in the soil organic matter, fine root biomass, total porosity, clay content, and soil bulk density. Notably, the soil amendments did not significantly affect the hydrological properties of the deep soil layer (40-80 cm). Our study demonstrated that the strategic use of AS and BC, particularly in combination, effectively enhanced soil fertility and hydrological functions, thereby increasing grassland ecosystem productivity. These findings offer critical insights for sustainable grassland management and highlight the potential of tailored soil amendments to restore and improve soil fertility and plant productivity in degraded grassland ecosystems.

Sequestering farmland for secondary succession is an effective method of restoring ecosystem services to degraded farmland, but long-term secondary succession often alters ecosystem environments, resources, and substrate stoichiometry. Currently, it is not known how resource changes and stoichiometric imbalances due to secondary succession affect soil microbial community structure and function, hindering our understanding of the natural resilience for degraded ecosystems. Here, we assessed nutrient limitation elements, community structure, metabolic functions, co-occurrence network complexity, and community stability of soil microorganisms during secondary succession of abandoned farmlands on the Loess Plateau. Results showed that secondary succession significantly altered plant characteristics and soil properties, as well as causing stoichiometry imbalances in nutrient resources. Along the secondary succession chronosequence, microbial nutrient metabolism shifted from phosphorus (P) limitation to carbon (C) and nitrogen (N) co-limitation. Microbial diversity, eutrophic flora, plant growth-promoting bacteria, and metabolism functional groups increased significantly during the 20 years after the abandonment of the farmlands, but decreased significantly with long-term succession. However, oligotrophic flora and P-solubilizing bacteria became dominant after 30 years of secondary succession on abandoned farmlands. The topological features of microbial co-occurring networks, including nodes, degree, closeness, betweenness, and eigenvector complexity, natural connectivity, and community stability first increased and then decreased with secondary succession. Correlation and random forest analyses indicated that secondary succession-induced stoichiometry imbalances in C:N and N:P, as well as changes in soil organic C and lignin phenols, were the key factors influencing microbial community structure and function. Overall, these results enhance our understanding of the adaptation strategies of soil microbial communities in ecologically managed regions to changes in ecosystem resources and stoichiometric imbalances.

Excessive use of N fertilizers (driven by high-yield goals) and its consequent environmental problems are becoming increasingly acute in agricultural systems. A 2-year field experiment was conducted to investigate the effects of three N application methods (application of solid granular urea once (OF) or twice (TF), application of solid granular urea mixed with controlled-release urea once (MF)), and six N rates (0, 60, 120, 180, 240, and 300 kg N ha-1) on maize yield, economic benefits, N use efficiency, and soil N balance in the maize (Zea mays L.) film mulching system on the Loess Plateau, China. The grain yield and economic return of maize were significantly affected by the N rate and application method. Compared with the OF treatment, the MF treatment not only increased the maize yield (increased by 9.0- 16.7%) but also improved the economic return (increased by 10.9-25.8%). The agronomic N use efficiency (NAE), N partial factor productivity (NPFP) and recovery N efficiency (NRE) were significantly improved by 19.3-66.7, 9.0-16.7 and 40.2-71.5%, respectively, compared with the OF treatment. The economic optimal N rate (EONR) of the OF, TF, and MF was 145.6, 147.2, and 144.9 kg ha-1 in 2019, and 206.4, 186.4, and 146.0 kg ha-1 in 2020, respectively. The apparent soil N loss at EONR of the OF, TF, and MF were 97.1-100.5, 78.5-79.3, and 50.5-68.1 kg ha-1, respectively. These results support MF as a one-time N application method for delivering high yields and economic benefits, with low N input requirements within film mulching spring maize system on the Loess Plateau.

Plastic film mulching (PM) and nitrogen (N) fertilization regimes significantly affect crop yield, N supply capacity, and N losses. However, the long-term effects and the underlying mechanisms, like the belowground N transformations, call for in-depth investigation. Here, a N-15 tracing study was conducted to quantify the gross N transformation rates of the calcareous soil subjected to 12 years of PM and various fertilization regimes. We found that autotrophic nitrification (ONH4) and mineralization (M) were the predominant soil N conversion processes, while dissimilatory nitrate reduction to ammonium (DNRA) and nitrate immobilization (INO3) were negligible in the calcareous soil, leading to the accumulation of nitrate. Long-term PM significantly decreased the rates of M, recalcitrant organic-N mineralization (MNrec), ONH4, and NH4+ immobilization to labile organic-N (INH4_Nlab) due to the negative effect on the abundances of fungi and ammonia-oxidizing bacteria (AOB) amoA gene compared to control soil. Relative to no N control, different fertilization regimes significantly increased the AOB amoA gene abundance, decreased fungal abundance and ITS:16S ratio, thus increasing ONH4 and M, decreasing NH4+ immobilization rates to labile and recalcitrant organic-N. Compared to normal N rate (F-225), high N rate (F-380) and normal N plus manure (F225+M) markedly increased ONH4 and INO3. Regression analyses revealed that M and AOB amoA gene abundance affected ONH4, and in turn N2O production. The findings provide an improved understanding of the long-term effects of PM and N managements on soil N supply capacity and potential N losses based on internal N cycling and molecular biology.

Water stress is the most important factor limiting crop production in arid and semiarid regions. Cultivating crops using a plastic film mulch can significantly increase crop yields by optimizing soil hydrothermal conditions in semiarid agroecosystems. Therefore, clarifying root adaptability to plastic film mulch cultivation is crucial when attempting to produce stable and high maize yields. A two-year experiment was conducted to investigate the effects of two treatments, no mulching (NM) and plastic film mulching (FM), on the yield, water productivity (WP), and root morphology of spring maize on the Loess Plateau. The results showed that the FM yield (14.31–15.02 t ha–1) significantly increased by 18.6–29.7 % compared to NM (11.03–12.66 t ha–1). The FM treatment also significantly increased dry matter (51.0–61.6 %), leaf area (19.7–25.7 %), and WP (28.8–46.3 %), but decreased ET (8.6–12.8 %). In addition, soil water storage in the FM surface soil layer significantly increased compared to that of NM. Film mulching also produced more robust roots and promoted the convergence of roots towards the surface of the soil, whereas NM roots tended to grow downwards to obtain water from the lower soil layers. The regression analyses indicated that root length (R2 = 0.725, P < 0.01) and biomass (R2 = 0.736, P < 0.01) were positively correlated with grain yield. The results suggested that maize adapts to changes in root morphological behavior under FM. These changes contribute to soil water and nutrient capture and shoot development, which subsequently support the high yields produced under plastic film mulching. Therefore, film mulching is a promising strategy for improving yield and WP and for optimizing root morphology in dryland agriculture.

Screening maize (Zea mays L.) cultivars for high grain yield while conserving nitrogen (N) fertilizer is of long-term strategic importance in addressing food security and environmental pollution issues. Limited knowledge exists regarding the differences in N efficiency of modern high-yielding cultivars and the agronomic traits that contribute most to grain yield. Revealing these physiological traits is crucial for understanding the limiting factors of grain yield potential in maize cultivars. A three-year (2018–2020) field experiment was conducted using 16 maize cultivars under low-N (LN) and high-N (HN) conditions. Low N stress reduced grain yield by 43% and yield components grain number per ear (GN), 100-grain weight (HKW) and number of ears per hectare (EN) by 22%, 12% and 13%, respectively. Analysis of the relationship between grain yield and agronomic traits has indicated a strong correlation with the accumulation of dry matter (DM) and N, most notably during the post-silking stage. The 16 cultivars were classified into four types according to the average yield of the test cultivars under the conditions of HN and LN as the dividing line. Under HN and LN conditions, the H0HN (efficient under both HN and LN conditions) cultivar type exhibited 21% and 60% higher grain yields compared to the L0LN (inefficient under both HN and LN conditions) cultivar type. The direct path coefficient linking GN to grain yield is 0.592, representing the primary contribution to the variance in grain yield. Under both HN and LN conditions, the H0HN cultivar type demonstrated a significant enhancement in post-silking dry matter accumulation, with increases of 30% and 64% over the L0LN cultivar type, respectively, while the N accumulation post-silking was elevated by 56% and 139%. The cultivars with H0HN and L0HN (efficient only under HN conditions) types had the potential to increase grain yield by 2.4%–6.1% and save 5.5%–15.7% of N fertilizer. Compared with L0LN cultivar type, H0HN cultivar type have higher N uptake efficiency and partial fertilizer productivity of N. In conclusion, the target traits for breeding modern N-efficient cultivars include higher post-silking DM accumulation and N accumulation. These traits play a positive role in increasing GN and the HKW, thereby fostering an increase in grain yield.

Screening genotypes with optimal root traits presents a promising breeding strategy for enhancing adaptability to abiotic stresses and improving resource use efficiency. This study evaluated root traits of 100 winter wheat genotypes under four treatments: control (C), low phosphorus (LP), PEG-induced drought (D), and a combination of LP and drought (DLP), using a semi-hydroponic phenotyping platform. Significant variations in root traits were observed 65 days after transplanting, with over 80% of traits being significantly affected by drought, phosphorus, or their interactions. Biomass and phosphorus content decreased under LP and drought, while root length and diameter in deeper layers increased, especially under drought stress. Combined stress led to the most severe reductions in biomass, P-content, and leaf number. Phosphorus acquisition efficiency was positively correlated with root length but inversely related to stress tolerance. High heritability traits, such as root number, root length, maximum root depth, leaf number, and biomass, hold potential for breeding programs focused on environmental adaptation, resource efficiency, and yield improvement. The substantial genotypic variation in root morphology under stress conditions highlights the potential for breeding stress-resilient wheat genotypes. This finding lays a foundation for wheat-breeding initiatives aimed at developing genotypes better suited to prevailing environmental conditions.

The application of synthetic nitrogen (N) fertilizer has increased anthropogenic N2O emission in global croplands. Due to the advantage of biological nitrogen fixation (BNF), the introduction of legume may lessen N2O emission intensity (emission/yield) in cereal field. Yet, this speculation lacks strong evidences and the relevant mechanistic explanations. A two-year field study was conducted using static chamber method (15N isotope labeling in fertilizer) in the mono- and inter-cropping fields with soybean introduced in maize field in semiarid rainfed Loess Plateau. The results indicated that maize-soybean intercropping showed 13 % lower N2O emission intensity than monocropping, attributed to 14 % and 20 % lower annually N2O emissions in intercropped zone than that of sole maize and soybean zones respectively. Also, a 15 % higher grain yield was observed in intercropped maize relative to that in sole maize. Particularly, during the peak time of emission following N fertilization and BNF within growing season, soybean introduction reduced 25 % and 24 % of N2O emissions in intercropped zone than sole maize and soybean zone respectively. It also favored maize plant with an additional 17 % more fertilizer-derived N, 21 % less soil-derived N and 30 kg N ha-1 soybean transferred-N from BNF. The contributions of N fertilization, BNF and soil initial organic N to N2O production were lessened in intercropping. In this case, the capacity of substrates N transformation into N2O emissions was lowered. Critically, soybean introduction reduced soil ammonia oxidation (as evidenced from amoA AOA and AOB gene abundance) in intercrops' rhizosphere, and increased soil nitrite reduction (nirS and nirK gene abundance) in maize rhizosphere, and improved soil N2O reduction to N2 (nosZ gene abundance) in soybean rhizosphere. Therefore, soybean introduction optimized N source use for lower N2O emission intensity, via reducing the transformation of substrate N into N2O, and modifying the expression of nitrification and denitrification functional genes.

Long-term overfertilization not only aggravates environmental costs, but reduces the quality and yield of fruit in dryland apple orchard, and this issue is closely associated with post-germination fertilization management. On the basis of multi-year observations, we developed a targeted fertigation strategy of FORD, i.e. formula fertilization (rational fertilizer scheme), on-demand fertilization in the sensitive period, reduced fertilization and delayed fertilization. Two-year field investigations were conducted with conventional furrow application (CK), integrated furrow and injection application (FI) and the optimized injection application under the FORD principle in a semiarid apple orchard. The data indicated that FI and FORD had a similar fruit yield of 57.2 Mg ha-1, significantly greater (by 4.5%) than CK. Yet, fruit quality (nutrition, flavor and appearance) was substantially improved under FORD, relative to FI and CK (P<0.05). Importantly, FORD did not induce secondary salinization (soil electric conductivity (EC) of 100-500 μs cm-1, pH of 7.8), but significantly improved soil microbial biomass carbon and the activities of carbon turnover key enzymes (β-glucosidase and cellobiohydrolase). As a result, FORD induced a better functioning of leaves, and a faster speed of fruit expansion than CK and FI did. Totally, the above parameters were positively associated with the efficient couplings of water and fertilizer, which critically depended on nutrients rational supply in FORD. Notably, relative to CK and FI, FORD reduced the fertilization cost by 27.8% and 8.3% respectively, accordingly harvesting 38.1% and 11.6% higher net economic return (2.94×104 US$ ha-1). In summary, there existed remarkable positive effects of FORD-led fertigation strategy on fruit yield, quality and economic benefits. The FORD can be viewed as a general environment-friendly strategy to guide apple post-germination fertilization management for greater economic benefits.