Yield, Quality, and Water and Fertilizer Partial Productivity of Cucumber as Influenced by the Interaction of Water, Nitrogen, and Magnesium

Abstract

The balanced management of water and nutrient factors is essential for the high-efficiency production of cucumber. The effect of magnesium coupling with water and nitrogen on cucumber was determined using a three-factor and three-level orthogonal rotation combination design experiment, and the yield, quality, and water and fertilizer efficiency of cucumber were studied. Yield was significantly influenced by the single factor of irrigation or nitrogen, with the largest value of 88,412.6 kg/ha under high levels of irrigation and nitrogen input. The increase in magnesium fertilizer has a significant promoting effect on reducing sugar and free amino acids, with results 19.0% and 9.8% higher than that of low magnesium application, respectively. The interaction of irrigation and magnesium alleviated the negative effects of nitrogen deficiency, thereby reducing the risk of nitrate accumulation and improving the partial productivity of nitrogen fertilizer. The interaction of nitrogen and magnesium significantly affected the yield of cucumber, and all the quality indicators except vitamin C and the partial productivity of water and fertilizer. Six indicators from three categories of yield, quality, and efficiency were used to establish the comprehensive evaluation system based on correlation analysis, and yield was assigned the highest combined weight of 0.4023 using game theory. Grey relational analysis model was adopted to evaluate the water and fertilizer treatments, and the optimal applied combination was irrigation of 653.7 m3/hm2, nitrogen fertilizer (CH4N2O) of 1141.9 kg/ha, and magnesium fertilizer (MgSO4.7H2O) of 422.1 kg/ha. This condition comprehensively promoted yield, quality, and efficiency, providing a scientific water and fertilizer management strategy for cucumber production in Northwest China.