亏缺灌溉西瓜营养生长期适宜滴灌频率研究

为了探求膜下亏缺灌溉条件下大棚西瓜营养生长期的最佳滴灌频率，为西北干旱半干旱地区设施西瓜合理灌溉提供理论指导，笔者以‘农科大11 号’西瓜为试材，以室内蒸发皿水面蒸发量的0.4 倍为亏缺灌水量，试验共设置T1、T2、T3 共3 个灌水频率处理，分别为每2 天灌1 次水（高频）、每4 天灌1 次水（中频）和每6 天灌1 次水（低频），研究了滴灌频率对西瓜营养生长期根区土壤含水量、植株生长以及相关生理指标的影响。试验结果表明：T2 下根区0~20 cm土层的土壤水分条件最适宜营养生长期的生长，植株叶绿素含量、净光合速率和叶片水分利用效率达到最高，光合同化能力强，且西瓜叶片能够保持适宜的细胞汁液浓度和细胞水分代谢水平。整体而言，T2 西瓜营养生长期长势较好，植株健壮，抗逆性更强，有利于抵抗早春大棚各种逆境胁迫。综合考虑土壤水分分布、生理及生长指标，T2 即每4 天灌1 次水是西北地区早春大棚西瓜营养生长期亏缺灌溉条件下最佳灌溉频率。该研究可为提高西瓜营养生长期亏缺灌溉水分利用效率提供参考依据。

Research on Suitable Drip Irrigation Frequency Under Deficit Irrigation at Watermelon Vegetative Period

Objective]The research was aimed at obtaining an optimalSirrigationSfrequency for watermelonSat seedling stage under mulched drip irrigationSand deficit irrigation condition inSplastic greenhouse, and provided theoretical guidance forSreasonable irrigation of watermelon in arid and semi-arid area inSnorthwest of China. Method] It adopted Nongkeda NO.11 watermelon as test material and 0.4Ep of evaporation pan indoor as deficit irrigation amount, 3 irrigation frequency treatments were designed, which were T1 (high frequency) of once every 2 days, T2 (intermediate frequency ) of once every 4 days and T3 (low frequency ) of once every 6 days, respectively, and finally the effects of different frequency treatments under mulched drip irrigation on root zone soil water content, plant growth and related physiological indexes of watermelon were studied. SResult] The results showed that the root zoneSsoil moisture of 0~20 cm soil layer under T2 treatment condition was optimum forSthe growth of watermelon seedling, and the level of chlorophyll content, net photosynthetic rate, assimilation capacity of photosynthetic and leaf water use efficiency of T2 was superior to other treatments,meanwhile,the watermelon leaves of T2 can maintain an appropriate level of leafScell sap concentrationSand intracellular water metabolism. As a whole, under intermediate frequency irrigation treatment at watermelon seedling stage (T2), the watermelon seedling grew well and the plant was robust, and which have more advantages against adversity stress in early spring. Conclusion] ComprehensivelySconsidered soil moistureSdistribution, physiological index andSgrowth index, T2, that is, water irrigation frequency of once every 4 days under deficit irrigation condition, is the optimum irrigationSfrequency for watermelon at seedling stageSin plastic greenhouse at early spring in northwest of China.