The synergistic effect of magnetoelectric water drip irrigation and foliar zinc application on the yield, quality and water use efficiency of spinach

• Magnetoelectric activated water drip irrigation effectively improved soil environment. • Drip irrigation and foliar fertilizer optimized water and nutrient utilization. • Magnetoelectric activated water combined with 0.2 % foliar zinc promoted spinach yield. • Water use efficiency is a key factor affecting the yield and quality of spinach. The vegetable cultivation industry offers high added value and short-cycle returns, with market demand exhibiting a continuous upward trend that far exceeds that of traditional grain crops. However, low water use efficiency and the deficiency of soil micronutrients have become critical constraints to improving vegetable yield and quality. Among these, zinc, as a key micronutrient for vegetables, directly influences plant growth and development, yield formation, and quality enhancement. This study focuses on spinach and aims to investigate the synergistic effects and underlying mechanisms of different irrigation methods and foliar zinc application concentrations on the physiological growth and water-nitrogen use efficiency of spinach under magnetoelectric water irrigation. The objective is to provide a theoretical basis and practical guidance for efficient vegetable cultivation and water-fertilizer management. The experiment was designed with two irrigation methods—drip irrigation (D) and border Irrigation (M)—and five foliar zinc application concentrations (based on the mass fraction relative to irrigation water): 0 % (Zn1), 0.05 % (Zn2), 0.1 % (Zn3), 0.15 % (Zn4), and 0.2 % (Zn5). The control group (CK) utilized conventional irrigation water with two zinc concentration levels: 0 % (Zn1) and 0.1 % (Zn3). The results showed that the DI-Zn5 treatment achieved the best overall response in spinach. Compared with other treatments, spinach under DI-Zn5 exhibited increases in aboveground fresh weight by 8.89 %-142.92 %, plant height by 0.57 %-97.04 %, net photosynthetic rate by 9.49 %-154.91 %, total nitrogen content by 10.41 %-60.93 %, total carbon content by 0.36 %-46.40 %, total zinc content by 3.75 %-117.15 %, water use efficiency by 10.69 %-360.52 %, nitrogen partial factor productivity by 9.79 %-201.64 %, soluble sugar content by 1.82 %-37.27 %, and soluble protein content by 1.26 %-31.25 %. These results indicate that the synergistic application of magnetoelectric water drip irrigation and foliar zinc fertilization enhances soil physicochemical properties, thereby improving the efficiency of resource element utilization within the crop environment. Notably, water use efficiency was a key factor affecting the yield and quality of spinach. Therefore, implementing drip irrigation combined with 0.2 % foliar zinc application under magnetoelectric water irrigation conditions constitutes the optimal water-fertilizer regime for spinach. This approach significantly promotes spinach growth and development, improves yield and quality, and provides scientific evidence and methodological support for enhancing irrigation efficiency, optimizing the synergistic effect of water and fertilizer, and achieving efficient resource allocation and sustainable agricultural development.