Saline-alkali soil is a major threat to global food security. Phosphorus (P) fertilizer is essential for crop growth and yield production. Nevertheless, the optimal phosphate fertilizer application rates for summer maize under coastal saline–alkali soil are still unclear. A field experiment with five phosphate application rates (0, 45, 90, 135, and 180 kg ha⁻¹, referred to as T1, T2, T3, T4, and T5, respectively) was conducted during the 2018–2020 summer maize seasons study the effects of phosphate rates on the grain yield, biomass, and nitrogen (N), P and potassium (K) accumulation, and N, P, and K physiological efficiency (denoted as NPE, PPE and KPE, respectively). Results showed that P application notably improved maize grain and biomass yield, the total uptake of N, P, K, and NPE and KPE across three seasons. As the P addition increased to 135 kg ha⁻¹, the grain yield achieved a maximum of 7168.4 kg ha⁻¹, with an average NPE of 2.15 kg kg⁻¹, PPE of 0.19 kg kg⁻¹, and KPE of 1.49 kg kg⁻¹. However, PPE continuously decreased with the input of phosphate. P application rates exceeding 135 kg ha⁻¹ were not considered effective due to a decline in grain yield, nutrient uptake, and NPE. Furthermore, the effect of the planting season was significant on the total uptake of N and K, and the use efficiency of N, P, and K. TOPSIS revealed that a phosphate application rate of 90–135 kg ka⁻¹ was the optimal pattern for maize production. These results may give a theoretical basis for the phosphate management of maize production in saline–alkali soil.

Water scarcity is the most significant constraint for grain production in the North China Plain (NCP). Water-saving irrigation technology is a valuable tool for addressing the NCP’s water scarcity. Drip irrigation is considered as one of the most water-saving irrigation technologies. However, drip irrigation is not now commonly used in NCP field grain crops (particularly maize). Fertilizers are accurately administered to summer-maize root soil by recycling the drip-irrigation system of winter wheat. To increase the water and fertilizer-use efficiency of summer-maize fields, the coupling body of root-zone soil water and fertilizer for summer maize was thoroughly adjusted using a combination of emitter flow rate, irrigation quota, and fertilizer frequency. In this experiment, a split plot design with randomized blocks was employed. The primary plot was emitter flow rate (0.8 and 2.7 L/h), the subplot was irrigation water quota (120 and 150 m³/hm², 1 hm² = 10,000 m²), and the final plot was fertigation frequency (7, 14, and 28 days). The grain yield, water-use efficiency and fertilizer-use efficiency of summer maize were measured in this study. The results showed that grain yield and water-use efficiency (WUE) of the small-flow drip-irrigation treatment (emitter flow rate < 1 L/h) were significantly higher than the large-flow treatment (emitter flow rate > 1 L/h); the rates of grain yield increase were 8.2% and 13.3% and WUE were 3.5% and 8.0%, respectively. A higher irrigation quota can increase the yield of summer maize. The maximum yield and WUE were observed at the fertigation frequency of 7 days under small-flow drip-irrigation conditions. All comparisons and analyses showed that small-flow drip irrigation combined with high fertigation frequency could obtain higher yield and WUE in the NCP. This study proposes a new way to improve water and fertilizer utilization efficiency to achieve the goal of “increasing grain yield by fertilizing” and “adjusting the quality by fertilizing”, from the perspective of winter wheat–summer maize no-tillage annual rotation planting.

Enhancing crop productivity on alkali soils is essential for food security; however, excessive fertilizer use can lead to soil salinization. Wheat, as a key staple crop, requires an appropriate nitrogen-to-phosphorus fertilization ratio to optimize its yield, yet the ideal ratio remains unclear. In this study, alongside the application of potassium and organic fertilizers, we investigated varying nitrogen application rates (100 kg/ha, 180 kg/ha) and phosphorus application rates (40 kg/ha, 80 kg/ha, 120 kg/ha). The results revealed that, under consistent nitrogen application conditions, when phosphorus application increased from 40 kg/ha to 80 kg/ha and 120 kg/ha, average yield increased by 13.6–25.1% and 0.1–12.6%, respectively. In contrast, under the same phosphorus application conditions, increasing nitrogen application from 100 kg/ha to 180 kg/ha resulted in a 2.6–17.6% increase in average yield. Among the factors considered, biomass emerged as the most significant determinant of yield (Standardized Path Coefficient (SPC) = 0.84), with key influences on biomass including soil alkali-hydrolyzable nitrogen, phosphorus uptake, and potassium uptake. The optimal fertilization strategy for wheat production on alkali soils was found to be 180 kg/ha of nitrogen and 80 kg/ha of phosphorus. These findings provide a theoretical foundation for optimizing fertilizer management in wheat cultivation on alkali soils.

Choosing the proper fertilizer regime for a crop in a given location remains challenging to increase yield, profitability, environmental growth protection, and sustainability. However, the nutrient demand characteristics of cotton in the North China Plain are different at various growth stages. Therefore, we choose the local superior cotton variety (Lumian 532) with high yield as the material, in the present study, we assessed the cotton yield, biomass accumulation and distribution, nitrogen absorption and utilization efficiency, and other parameters by setting four nitrogen allocation ratios (3:5:2, 0:10:0, 3:7:0, and 0:7:3) when the nitrogen application rates were 0, 150, 220, and 300 kg hm⁻². The results showed that when the nitrogen application rate was 300 kg hm⁻², the growth index, biomass, nitrogen content, and yield of Lumian 532 were the highest, while the nitrogen partial productivity (12.2 and 12.8) was the lowest. When the nitrogen application rate was 220 kg hm⁻² and the nitrogen allocation ratio was 3:5:2, the agronomic nitrogen use efficiency (3.2 and 3.5) and nitrogen physiological (24.8 and 25.0) was achieved. When the nitrogen application rate was 150 kg hm⁻², the nitrogen partial productivity (20.6 and 20.9) was the highest. In conclusion, the biomass accumulation and distribution, nitrogen use efficiency, yield, and yield composition of Lumian 532 could be effectively regulated by appropriate nitrogen application rate and nitrogen allocation ratio. Therefore, to optimize the yield and improve the nitrogen use efficiency, the optimal nitrogen application rate of Lumian 532 was 220 kg hm⁻², and the optimal nitrogen allocation ratio was 3:5:2 in the North China Plain. The results provided practical basis for nutrient demand, cotton yield and ecological protection in different growth stages of cotton in North China Plain.

The fundamental solution to the problem of emitter clogging is to explore the optimal structure design of emitter and improve its anti-clogging ability. The research objective was to select the optimal structural form of the emitter flow path in drip irrigation systems using inferior water sources, which can provide theoretical support for improving the anti-clogging ability of the emitter itself and designing new emitter products. The selection of the flow path structure of the emitter has not been conducted on the basis of determining the appropriate simulation model with the condition of complex water quality. Therefore, the appropriate internal fluid movement model of the emitter was determined, the hydraulic performance and anti-clogging performance of the five nationally and internationally representative flow path structures were comprehensively evaluated, and finally the optimal structure of the emitter flow path was determined. The research results indicated that RNG k - ε model was the most suitable to simulate the flow field in the emitter by comprehensive analysis of the gap between simulated values and the measured values, the calculation accuracy and computational efficiency. The fractal flow path was relatively optimal for hydraulic performance and for anti-clogging performance. This study can provide theoretical support for improving the anti-clogging ability of the emitter itself and the design of the new emitter product.