Introduction: High-yield and high-quality production of silage maize in cold regions is crucial for ensuring the sustainable development of livestock industry.Methods: This study first conducted an experiment to select the optimized silage maize varieties and densities using a split-plot design. The tested maize varieties were Xuntian 3171, Xuntian 16, Xunqing 858, and Fengtian 12, with each variety planted at densities of 67,500, 79,500, and 90,000 plants ha^-1. Following the variety and density selection, another experiment on optimizing nitrogen management for silage maize was carried out using a completely randomized design: no nitrogen fertilizer (T1), applying urea-N 320 kg ha^-1 (T2), applying urea-N 240 kg ha^-1 (T3), applying polymer-coated urea-N 240 kg N ha^-1 (T4), and ratios of polymer-coated urea-N to urea-N at 9:1 (T5), 8:2 (T6), 7:3 (T7), and 6:4 (T8). T5-T8 all applied 240 kg N ha^-1. The yield and quality of silage maize, nitrogen use efficiency and balance, and economic benefits were evaluated.Results: Results showed that Xunqing 858 had significantly higher plant height (8.7%-22.6% taller than the other three varieties) and leaf area (30.9% larger than Xuntian 3171), resulting in yield 11.5%-51.6% higher than the other three varieties. All varieties achieved maximum yields at a planting density of 79,500 plants ha^-1. Integrated management strategy 7 (T7: Xunqing 858, 79,500 plants ha^-1, polymer-coated urea-N to urea-N ratio of 7:3) achieved the highest yield of 73.1 t ha^-1, a 6.1%-58.1% increase over other treatments. This strategy also produced the highest crude protein (11.1%) and starch (19.1%) contents, and the lowest neutral detergent fiber content (50.6%), with economic benefits improved by 10.3%-97.8% compared to other strategies. Additionally, T7 improved nitrogen use efficiency by 15.4%-94.5%, reduced soil nitrate leaching by 4.4%-36.5%, and decreased nitrogen surplus by 7.0%-46.6%.Conclusion and discussion: Comprehensive analysis revealed that the integrated management strategy 7 significantly improved silage maize yield and quality in cold regions while enhancing nitrogen use efficiency and reducing the risk of nitrate leaching, aligning with green agriculture development requirements. These findings will provide vital theoretical insights and practical guidance for high-yield and high-quality silage maize production in cold regions worldwide.

Sustainable intensification of protected vegetable crops entails increasing yield while reducing environmental impact and labor input. To explore a comprehensive strategy for high yielding, highly efficient and high quality production of greenhouse tomato (Solanum lycopersicum L.), an integrated crop-nitrogen management (ICNM) strategy was compared to farmers’ traditional management (TM) in a field experiment in a solar greenhouse. A split-plot block design was used. The main factor was the management strategy of ICNM and TM. The secondary factor was four different basal fertilizer treatments, being a control (CK; 0 kg N ha⁻¹), carbon-based urea (BU; 100 kg N ha⁻¹), controlled release urea (CU; 100 kg N ha⁻¹), and conventional compound fertilizer (CF; 100 kg N ha⁻¹). An additional 200 kg N ha⁻¹ through drip irrigation as topdressing was used. Tomato fruit yield, N uptake, and N partial productivity with ICNM were significantly higher than with TM, increasing by 32.1%, 39.7%, and 31.1%, respectively. The proportion of fine roots was increased in ICNM, and the average diameter of roots decreased by 10.7% compared to TM. There was a significant negative correlation between mean root diameter and N uptake. In conclusion, the ICNM strategy was beneficial to form a good root system configuration, promote the development of shoot biological potential, increase tomato yield, maintain fruit quality, increase N uptake, and reduce environmental risks.

This study evaluated the effects of water–fertilizer coupling on the water and fertilizer use efficiency, yield, and quality of fresh common beans (Phaseolus vulgaris L.) in high-latitude and high-altitude regions. For field water-saving, in 2022, six treatments were established, with irrigation rates of 100% FC (W1), 90% FC (W2), 80% FC (W3), 70% FC (W4), 60% FC (W5), and 50% FC (W6). Based on the experiment in 2022, a two-factor experiment (irrigation and fertilizer application rate) was implemented in 2023, and three fertilizer (N−P₂O₅−K₂O) gradients were established: F1 (260−192−255 kg/ha), F2 (195−144−192 kg/ha), and F3 (131−97−127 kg/ha). Based on 2022, three irrigation rates were established at percentages of FC: W7 (100% FC), W8 (80% FC), and W9 (60% FC). Experiments in both years revealed a quadratic relationship (parabola equation) between yield and the rates of both irrigation and fertilization. Excessive fertilization did not consistently enhance yield, and reduced fertilizer application resulted in higher fertilizer partial factor productivity (PFP). Both years of experiments indicated that maintaining soil moisture at 80%~90% field capacity (FC) significantly improved fresh pod yield and water use efficiency (WUE) compared to other treatments. Under the same fertilizer level, reduced irrigation increased key fresh pod quality indicators, such as single-pod weight and soluble sugar content. In contrast, across varying fertilizer rates, these same indicators showed a positive correlation with the amount of fertilizer applied. Vitamin C (VC), soluble protein (SP), soluble solids content (SSC), and nitrate content (NC) reached their highest levels under high fertilizer treatment (N−P₂O₅−K₂O: 260−192−255 kg/ha). Based on the differential comprehensive evaluation models, the study concluded that maintaining soil moisture at 80%~90% FC and applying fertilizer between N−P₂O₅−K₂O: 195−144−192 kg/ha and N−P₂O₅−K₂O: 260−192−255 kg/ha was the optimal strategy. This approach can alleviate the water scarcity pressure in high-latitude and high-altitude regions, and facilitate the selection of common bean management practices that maintain yield while improving quality and PFP, thereby offering theoretical and practical guidance for adapting water–fertilizer regimes to local climatic conditions.