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.

Composite fouling, arising from microbial and inorganic interactions, compromises the reliability of reclaimed-water distribution systems. We evaluated permanent magnetic fields (PMF; 300–800 mT) and electromagnetic fields (EMF; AC and pulsed DC) in a full-scale reclaimed-water distribution loop. Under the tested conditions, EMF—particularly pulsed DC—reduced total foulant mass by up to 51.7% ( p < 0.05) and was associated with lower biofilm biomass, mineral scaling, and particulate accumulation. 16S rRNA profiling indicated co-occurring declines in community diversity and simpler co-occurrence networks under EMF. X-ray diffraction indicated a relative enrichment of aragonite (vs. calcite) and decreases in dolomite and quartz within deposits across all magnetic-field treatments. Field-induced oxidative conditions and interfacial changes were consistent with processes that may hinder microbial attachment and crystal nucleation. Collectively, the results suggest that EMF can outperform PMF for composite-fouling control in reclaimed-water systems and motivate optimization of field strength and waveform and validation across additional water qualities and hydraulics.