To increase crop productivity while reducing environmental costs, an integrated soil–crop system management (ISSM) strategy was developed and successfully adopted in China. However, little information is available on the long-term ISSM effects on maize agronomic and environmental performance. Therefore, we evaluated the effects of ISSM with combining inorganic and organic fertilizers on maize productivity, N use efficiency (NUE) and N balance and losses as compared with farmers’ practice (FP) and high-yielding practice (HY), based on an 11-year field experiment in Northeast China. Maize yield in ISSM (11.7–14.3 Mg ha⁻¹) achieved 97.7% of that in HY and was increased by 27% relative to FP. The excellent yield performance in ISSM was mainly attributed to optimum plant population structure and yield components. Annual N surplus in ISSM was only 7 kg ha⁻¹, which was considerably lower than that in FP (52 kg ha⁻¹) and HY (109 kg ha⁻¹). Consequently, ISSM obtained significantly lower N losses and greenhouse gases emissions and higher NUE. In contrast to FP, crop performance in ISSM showing better sustainability and inter-annual stability. In conclusion, ISSM is an effective strategy to achieve long-term sustainable high crop yields and NUE with less environmental costs in the intensive agricultural system.

Ammonia volatilization is an important nitrogen (N) loss pathway in agricultural production and consequent significant atmospheric pollutant. The primary objective of this study was to (1) examine effects of environmental factors such as temperature and soil water capacity, as well as crop residue (CR) addition as fertilizer, on ammonia (NH₃) volatilization, and (2) search for a comprehensive management strategy to reduce accumulative ammonia volatilization (AAV). A bench-scale cultivated experiment was conducted at two environment temperatures (15 or 25 °C), three forms of soil water capacity (30%, 50%, or 70% soil field moisture capacity), and two treatments of fertilizers (conventional fertilizer urea and straw returning – 10% of total N application arising from maize straw and remainder from conventional urea). Results showed that AAV was markedly decreased by adjusting soil water capacity, temperature, and CR addition. Significant quantified exponential correlation between AAV and soil moisture was observed. More than 70% AAV was reduced in intermediate 50% and high 70% soil moisture compared to low 30%. AAV was less sensitive to temperature than soil moisture using black soils. Only in low soil moisture, AAV rose with increasing of temperature. Straw restoration addition decreased significantly the AAV loss.

A well-developed rhizospheric system is crucial for maize to adapt to environmental stresses, thereby enhancing yield and quality. However, nitrogen (N) stress significantly impedes rhizospheric development and growth in maize. The genetic responses of maize’s rhizosphere to N stress under monocropping systems with exogenous inorganic N fertilization and intercropping systems reliant on biological N fixation are not well understood, especially regarding common and specific response genes. Therefore, through transcriptomic analysis, this study systematically investigated the gene expression and molecular responses of maize’s rhizosphere under two N supply regimes to N stress. The results showed that N stress generated 196 common and 3350 specific differentially expressed genes across the two systems, with the intercropping system exhibiting a stronger specific response. KEGG analysis revealed that the common genes, though few, are involved in key pathways essential for crop growth. Maize monocropping specific differentially expressed genes (MM) were enriched in pathways related to membrane lipids, cell wall formation, and intracellular signaling, while maize/alfalfa intercropping specific differentially expressed genes (MA) were linked to stress resistance through the glutathione metabolic pathway. WGCNA analysis identified five co-expression modules (CM). MA significantly increased the transcription factor families and structural domains directly targeting rhizospheric growth and development genes, including AP2, GRAS, Cys2His2 Zinc Finger, and LBD in CM blue. Conversely, MM significantly increased the transcription factor families and NAC structural domain targeting the promoters of N transporter protein genes in CM pink. This study emphasizes the importance of both common and specific genes in maintaining maize growth under suboptimal N supply in monocropping and intercropping systems.

Returning crop residues into fields, either alone or in combination with inorganic fertilizer, is considered as a practical way to enhance soil fertility. However, information concerning the effects of crop residues and inorganic fertilizer application on water extractable organic matter (WEOM) in soil is scarce. The aim of this study was to examine the 10-year effect of corn residue (CR) return with or without the application of nitrogen, phosphorus, and potassium (NPK) fertilizer on the quantity and quality of WEOM in a black soil of northeast China by means of ultraviolet absorbance, fluorescence excitation--emission matrix, and derived spectroscopic indices. The application of NPK fertilizers and CR, alone or together, increased the content of total soil organic carbon (SOC), water extractable organic carbon (WEOC), and ratio of WEOC/SOC, with the sequence being NPK + CR > CR > NPK > CK. Compared with control treatment, the individual application of NPK fertilizer decreased the aromaticity of WEOM. In contrast, elevated proportion of tryptophan-like fluorophore and microbially derived fulvic acid-like components with low molecular weight was detected in the WEOM. The amendment with CR alone resulted in increase in aromaticity of WEOM and proportion of plant-derived humic acid-like component with large molecular weight, accompanied by reduced proportion of tyrosine-like compounds. For the soil with CR restoration, the application of NPK fertilizer increased aromaticity of WEOM, and large molecular weight fulvic acid-like and humic acid-like compounds were found. However, the proportions of tyrosine-like and tryptophan-like compounds were diminished. The quantitative and qualitative analysis of WEOM using fluorescence spectroscopy describes responses to be observed in long-term different fertilization strategies.

Pesticide residues pose risks to the environment and human health. Little is known about how tillage and straw management affect herbicide behavior in soil. This study investigated the effects of different tillage practices under varying straw incorporation scenarios on the degradation of five commonly used herbicides in a long-term experimental field located in the maize belt of Siping, Jilin Province. Post-harvest soil samples were analyzed for residual herbicide concentrations and basic soil physicochemical properties. A human health risk assessment was conducted, and a controlled incubation experiment was carried out to evaluate herbicide degradation dynamics under three management systems: straw incorporation with traditional rotary tillage (ST), straw incorporation with strip tillage (SS), and no-till without straw (CK). Residual concentrations of atrazine ranged from not detected (ND) to 21.10 μg/kg (mean: 5.28 μg/kg), while acetochlor showed the highest variability (2.29–120.61 μg/kg, mean: 25.26 μg/kg). Alachlor levels were much lower (ND–5.71 μg/kg, mean: 0.34 μg/kg), and neither nicosulfuron nor mesotrione was detected. Soil organic matter (17.6–20.89 g/kg) positively correlated with available potassium and acetochlor residues. Health risk assessments indicated negligible non-cancer risks for both adults and children via ingestion, dermal contact, and inhalation. The results demonstrate that tillage methods significantly influence herbicide degradation kinetics, thereby affecting environmental persistence and ecological risks. Integrating straw with ST or SS enhanced the dissipation of atrazine and mesotrione, suggesting their potential as effective residue mitigation strategies. This study highlights the importance of tailoring tillage and straw management practices to pesticide type for optimizing herbicide fate and promoting sustainable agroecosystem management.

Simultaneous achievement of high yield and excellent quality in rice is essential for food security and human health. The coordinated application of nitrogen (N) and sulfur (S) can effectively increase the grain yield (GY) and grain protein concentration (GPC) of rice. A two-season field experiment was conducted to investigate the synergistic effects of combined N and S application on the GY and GPC of rice. This study employed four N rates (0, 120, 180, and 240 kg ha⁻¹, designated as N0, N1, N2, and N3, respectively) and four S rates (0, 30, 45, and 60 kg ha⁻¹, designated as S0, S1, S2, and S3, respectively) using two rice cultivars: Jiujiuxiang (JJX) and Jiuxiangyou (JXY). The experimental results demonstrate that N and S exert significant effects on the GY and GPC of rice, with notable interactive effects between these two nutrient elements. The synergistic fertilization of N and S enhanced the GY by improving rice plant photosynthesis and dry matter accumulation while increasing GPC through elevated cysteine concentration in grains. Compared to the unfertilized treatment, the GY of the JJX cultivar showed increases of 68.3–143.2% (Season I) and 59.4–133.4% (Season II) under combined N and S applications, while the GY of the JXY cultivar increased by 53.2–144.1% (Season I) and 66.0–192.9% (Season II). Similarly, the GPC of the JJX cultivar showed increases of 7.5–43.4% (Season I) and 5.7–43.9% (Season II) under combined N and S applications, while the GPC of the JXY cultivar increased by 13.1–66.7% (Season I) and 13.3–61.0% (Season II). Overall, whether on the JJX or JXY cultivars, the application of 180 kg ha⁻¹ of N combined with 45 kg ha⁻¹ of S (i.e., the N2S2 treatment) synergistically enhances GY and GPC in rice. The synergistic fertilization of N and S synergistically enhances both rice yield and nutritional quality by regulating plant growth dynamics, which meet the requirements for healthy and sustainable development in rice production systems.