根系分区交替灌溉条件下水肥供应对番茄有机酸含量的影响

采用分根法，通过盆栽试验，以四元二次回归正交旋转组合设计，研究了根系分区交替灌溉条件下灌水量和氮、磷、钾肥用量对番茄果实中有机酸含量的影响。通过回归分析，建立了番茄有机酸含量与水肥因子的数学模型。结果表明，在其他因子为中间水平时，番茄果实中的有机酸含量，随灌水量增加呈线性减小趋势；随施氮量增加表现为线性增长；随施磷量、施钾量增加呈开口向下抛物线型变化。交互效应表现为，灌水量与施钾量、施氮量与施磷量对番茄有机酸积累有显著的正交互作用。认为增施氮磷肥会增大番茄果实有机酸含量，合理施用钾肥、减小灌水量也促使番茄中有机酸的积累。

Effect of water and fertilizers on organic acid content of tomato under alternate partial root-zone irrigation

Quadratic orthogonal regressive rotation design with four factors was used to investigate the effects of irrigation amount and fertilizer rates of nitrogen, phosphorus and potassium on organic acid content in tomato by pot experiment under alternate partial root-zone irrigation, and the regression model on water and fertilizer and organic acid content in tomato was established. The results showed that, if other factors were at zero codes, the organic acid content in tomato decreased linearly with the increase of irrigation amount, while it increased linearly with the increase of nitrogen ertilizer rate. The relationship between organic acid content and phosphorus fertilizer rate or potassium fertilizer rate showed a changing trend as opening downward parabola. There were positive interaction effects between irrigation amount and potassium fertilizer rate, and between nitrogen fertilizer rate and phosphorus fertilizer rate. It was indicated that increasing the fertilizer rates of nitrogen and phosphorus could raise the organic acid content of tomato effectively; proper application of potassium fertilizer and proper reduction of irrigation water could also improve the accumulation of organic acid in tomato.