Combined Effects of Water and Nitrogen on Growth, Biomass, and Quality of Spinach (Spinacia oleraceaLinn.)

Water scarcity and nitrate contamination have caused considerable attention to environmental matters. Water and nitrogen interactions have critical impacts on their use efficiency, plant growth, and quality. In a field experiment, a combination of three water treatments and three nitrogen rates was applied to determine their interactive effects on the growth of spinach. Soil water supply that was too low [W3N1 (the combination of water treatment 3 and nitrogen treatment 1), W3N2] could cause an increase in nitrate content. Oxalate contents would increase when water and nitrogen were either inadequate (W3N0, W3N1) or too high (W2N2). The most profit from spinach was obtained in plots that received water treatment 2 and nitrogen fertilizer 78 kg N ha−1. However, considering nitrogen treatments could affect the nitrate and oxalic acid, application of water treatment 2 and 39 kg N ha−1 nitrogen fertilizer could get better spinach quality.