Effects of water and fertilizer supply on nitrate content in tomato fruit

【Objective】 The effects of irrigation amounts and fertilizer rates of nitrogen,phosphorus and potassium on nitrate content in tomato were investigated to improve the production of high quality tomato.【Method】 Jinpeng 1 was used as experimental material.Using a pot experiment and quadratic orthogonal regressive rotation design with four factors,a regression model of water and fertilizer mounts and nitrate content in tomato was established.Single and coupling effects of all four experimental factors were studied.【Result】 If other factors were zero codes,nitrate content increased at first and then eventually reduced as the increase of irrigation amount and or K fertilize rate while the nitrate contents constantly increased as the increase of P and N fertilizer rate.The interactions between irrigation amounts and K fertilizer rates and between N and P fertilizer rates were positive,while the interactions were negative between irrigation amounts and P fertilizer rates and between N and K fertilizer rates.【Conclusion】 It was indicated that nitrate content in low irrigation amount decreased when reducing P or with reasonable K fertilizer rate.It was effective to increase nitrate content in tomato by adding P or with reasonable K when N fertilizer rate was reduced.