Baozhong Yin

Leaf water content (LWC) is a key indicator of winter wheat water status, but the reliability of UAV hyperspectral and thermal infrared predictions varies across samples, limiting the effectiveness of fixed-weight fusion. To improve LWC estimation by integrating hyperspectral and thermal infrared data, this study developed a dynamic Granger–Ramanathan averaging (GRA) method. Sensitive bands were selected using the successive projections algorithm, and random forest, XGBoost, and LightGBM models were constructed for each data source. Generalized additive models were used to characterize relationships between canopy–air temperature difference (ΔT), normalized difference vegetation index (NDVI), and single-source prediction errors, enabling dynamic adjustment of fusion weights. Random forest performed best among the single-source models, with test-set R² values of 0.7871 and 0.6275 for hyperspectral and thermal infrared data, respectively. Conventional GRA achieved an R² of 0.7645, whereas ΔT- and NDVI-driven dynamic GRA increased R² to 0.8207 and 0.8224, respectively. The NDVI-driven model achieved the lowest RMSE (0.0646) and MAE (0.0497). Applied to 720 samples, it achieved an R² of 0.8507, an RMSE of 0.0591, and an MAE of 0.0451. These findings demonstrate the potential of crop-status-driven dynamic weighting to improve multisource LWC estimation in winter wheat.

Delayed sowing frequently occurs in the North China Plain (NCP), restricting pre-winter population establishment and reducing grain yield. To determine whether narrow row spacing can alleviate yield loss under delayed sowing by improving the pre-winter stem and tiller basis, a randomized block experiment with two row spacings and four sowing-date regimes with adjusted planting density was conducted from 2021 to 2024. Yield components, pre-winter stem and tiller number and quality, and anatomical and physiological traits of the main-stem base and tiller nodes were measured. The results showed that 7.5 cm narrow row spacing (R2) increased tiller occurrence and improved hormonal balance and non-structural carbohydrate accumulation in the main-stem base and tiller nodes, and was associated with enhanced anatomical structural integrity and pre-winter stem and tiller quality. R2 increased final spike number, grain number per spike, thousand-grain weight, and grain yield by an average of 2.8%, 8.6%, 3.9%, and 10.7%, respectively, with the greatest yield increase under moderately delayed sowing (S2, 17.7%), and structural equation modeling (SEM) supported this possible yield-increasing pathway (χ²/df = 1.38, GFI = 0.90).These results provide a theoretical basis and technical reference for stabilizing and increasing yield in delayed-sown winter wheat in the NCP.

Northeast China’s black soil region serves as a critical cornerstone of national food security, yet accelerating soil degradation, characterized by declining soil organic matter (SOM) and rising bulk density (BD), threatens the productive capacity of its farmland. Understanding how soil physicochemical properties regulate crop yields in this ecologically heterogeneous landscape is essential for sustainable agricultural development. Here, 2916 soil samples from 201 counties across six ecological zones were analyzed in conjunction with county-level rice and maize yield records. Our findings revealed that crop yield determinants are fundamentally governed by regional resource endowment characteristics rather than uniform factors. In areas characterized by sandy soil texture, low precipitation (1.34 g cm⁻³) and alkaline soil conditions (pH > 7.0) constitute the primary constraints to productivity through restricting root development. Conversely, in regions with fertile mollisols and high baseline soil organic matter (SOM > 40 g kg⁻¹), nutrient dynamics emerge as the dominant yield-regulating factors. For volcanic soil landscapes with strong phosphorus fixation capacity, available phosphorus deficiency represents the critical bottleneck for maize production. Path analysis further demonstrates that BD and pH operate predominantly through indirect mechanisms, modulating SOM accumulation and nutrient cycling rather than directly constraining yield. Threshold analysis identified that BD exceeding 1.34 g cm⁻³ and SOM below 26 g kg⁻¹ markedly reduce productivity, while SOM levels above 40 g kg⁻¹ yield diminishing marginal returns. These findings advance our mechanistic understanding and provide scientific foundations for spatially differentiated soil conservation and precision nutrient management strategies essential for sustaining grain production capacity in northeast China’s black soil region.

Increasing maize planting density is considered as a potential strategy for enhancing grain yield in Northeast China; however, its yield-enhancing effects and underlying regulatory mechanisms remain inadequately characterized. Based on 508 paired observations from 42 publications, this meta-analysis quantified the effects of increased planting density on yield components and elucidated the regulatory roles of environmental and agronomic factors. Results demonstrated that increased density intensified plant competition, raising grains per ear by 43.7% and 100-kernel weight by 6.7%. The optimal regional planting density was determined to be 89,622.6 plants ha⁻¹, achieving a peak yield of 12,143 kg ha⁻¹—significantly exceeding current conventional densities (49,000–65,000 plants ha⁻¹) and highlighting substantial yield potential. Although nitrogen (N) management did not alter peak yield levels, it significantly increased the optimal density threshold (reaching 99,600 plants ha⁻¹ under high N). Among environmental factors, mean annual precipitation (MAP) was the primary constraint: yield responses to increased density were negligible in arid regions (20 g kg⁻¹) and optimal bulk density (BD) (1.25–1.40 g cm⁻³) synergistically enhanced optimal density and peak yield. This study confirms the substantial, yet context-dependent, yield potential of increasing planting density in Northeast China, providing a science-based framework for region-specific optimization.

Optimized water-saving irrigation (WSI) practices are critical for enhancing resource use efficiency and ensuring sustainable wheat production in water-scarce regions. This meta-analysis quantitatively assessed the effects of various WSI methods on wheat yield, water use efficiency (WUE), and partial factor productivity of nitrogen (PFPN) across China’s wheat regions. The results showed that optimized irrigation, particularly drip and micro-sprinkler systems, significantly reduced irrigation water and nitrogen inputs by 35.1% and 7.2%, respectively, without yield penalties. Drip and micro-sprinkler irrigation, which together accounted for over 97% of observations, improved WUE by 18.7% and 10.1%, respectively, and increased PFPN by 6.8% and 5.5%, highlighting their dominant role in current WSI practices. Moderate deficit irrigation (60–100% of full irrigation) optimized WUE and PFPN while maintaining stable yields, whereas severe deficit irrigation (<40%) caused substantial yield losses. Soil texture and bulk density strongly modulated WSI effectiveness. Climatic factors, particularly growing season precipitation, negatively correlated with WSI benefits, highlighting enhanced efficiency gains under drier conditions. These findings emphasize the need to prioritize drip and micro-sprinkler irrigation in national water-saving strategies and advocate for integrated approaches combining WSI with soil health management and site-specific irrigation scheduling to promote sustainable wheat intensification under variable agroecological conditions.

Cover cropping has emerged as a pivotal sustainable agronomic practice aimed at enhancing soil health and sustaining crop productivity. To quantify its effects across diverse agroecosystems, we conducted a meta-analysis of 1877 paired observations from 114 studies (1980–2025) comparing cover cropping with bare fallow during fallow periods in major cereal systems across China. Cover cropping significantly reduced soil bulk density by 6.1% and increased key soil nutrients including total nitrogen (+13.1%), total phosphorus (+15.6%), hydrolysable nitrogen (+9.3%), available phosphorus (+11.1%), available potassium (+12.4%), soil organic matter (+11.7%), and microbial biomass carbon (+41.1%). Leguminous cover crops outperformed non-legumes in enhancing nitrogen availability, reflecting biological nitrogen fixation. Mixed-species cover crop mixtures showed superior benefits over monocultures, likely due to complementary effects on nutrient cycling and soil structure. Soil texture and initial soil organic carbon significantly moderated these outcomes. Furthermore, although overall soil pH remained stable, cover cropping exhibited a clear buffering effect, tending to regulate soil pH toward neutrality. Meta-regression analyses revealed a diminishing positive effect on total nitrogen (TN), available potassium (AK), and microbial biomass carbon (MBC) with an extended duration of cover cropping, suggesting potential saturation effects. These results underscore the context-dependent efficacy of cover cropping as a strategy for soil quality enhancement. Optimizing cover crop implementation should integrate the consideration of inherent soil characteristics, baseline fertility, and species composition to maximize agroecosystem resilience and sustainability.

Optimizing farmers’ crop production management is an effective strategy to synergize yields, resource utilization, and environmental conservation. However, the mechanisms by which agronomic management in the North China Plain (NCP) determines the wheat yield, water use efficiency (WUE), and physiological performance remain largely unexplored. To address this knowledge gap, a field experiment was conducted from 2022 to 2024 to investigate the effects of conventional farmer practices (CK) and a Integrated High-Yield and Efficiency Cultivation Management (HHL) strategy incorporating pre-sowing soil moisture creation, optimized tillage, fertilization, and irrigation on the yield, water consumption characteristics, leaf photosynthetic physiology, and root traits. The results demonstrated that HHL significantly enhanced the root morphology in winter wheat compared to CK. Specifically, HHL increased the net photosynthetic rate (Pn), chlorophyll content, and leaf area index (LAI) at the flowering stage by 20.5%, 8.8%, and 11.1%, respectively, thereby boosting dry matter accumulation by 40.3% and yields by 10.9%. Furthermore, HHL reduced soil water evaporation by 12.1% and the total water consumption by 112.1 mm, while improving the WUE by 25.4% and nitrogen fertilizer partial productivity by 38.7%, alongside a 12.5% increase in economic benefits. Through rigorous field experimentation, this study elucidates the potential of HHL in water conservation, yield enhancement, and comprehensive benefit improvement, offering an effective cultivation paradigm for the wheat production systems in the NCP. The findings indicate that this management strategy exhibits superior water-saving and yield-enhancing effects, with promising prospects for widespread adoption and application.

Growing green manure, as a sustainable agricultural practice, is widely recognized for its role in improving soil structure and enhancing soil quality. However, despite the significant benefits of green manure, research on how its application specifically influences soil organic carbon content remains insufficient, especially in the context of complex and ever-changing agricultural management models and ecological environments. In this study, 59 papers published from January 1980 to May 2024 were collected, and a database containing 299 groups of comprehensive effects of green manure planting on soil organic carbon content and crop yield, as well as its key regulatory factors, through a meta-analysis system. The research is mainly conducted through several key elements types of green manure, planting seasons, fallow periods of food crops, soil types, climate types, and planting years. The results show that compared with not growing green manure on fallow land, the cultivation of green manure significantly increased the soil organic carbon content (by 6.98%) and the yield of the next staple food crop (by 10.36%). In different planting seasons, both summer and winter planting of green manure can effectively increase the soil organic carbon (SOC) content and crop yield. Among them, the application effect during the fallow period of wheat and rice is particularly significant, while during the fallow period of maize, only the SOC content increases significantly. From the perspective of green manure types, both the single species of leguminous and the mixed species with cruciferous have shown good effects. The research also found that under soil types such as loam and clay loam, as well as climatic conditions like temperate continental climate, temperate monsoon climate, and subtropical monsoon climate, the effect of green manure planting on the increase of SOC and yield is more significant. In addition, the planting years are also an important influencing factor. Green manure planting for ≤3 a or >5 a can significantly improve the SOC content and crop yield. These findings provide important theoretical support for the scientific application and promotion of green manure in China.

Construction of a multifactor barrier evaluation system and classification of barrier types for arable land on the northern Huang-Huai-Hai Plain

Parameter optimization and experiment of the negative pressure precision seed-metering device for wheat