亏缺灌溉西瓜营养生长期适宜滴灌频率研究

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

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。

In order to obtain an optimal irrigation frequency for watermelon at vegetative period under mulcheddrip irrigation and deficit irrigation condition in plastic greenhouse, and provide theoretical guidance for thereasonable irrigation of watermelon in arid and semi- arid area in northwest of China, the author adopted‘Nongkeda NO.11＇as test material and 0.4 times of pan evaporation（0.4 Ep） as deficit irrigation amount, 3irrigation 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. Effectsof different frequency treatments under mulched drip irrigation on root zone soil water content, plant growthand related physiological indexes of watermelon were studied. The results showed that the root zone soilmoisture of 0-20 cm soil layer under T2 treatment condition was the optimum condition for vegetative periodgrowth, and the level of chlorophyll content, net photosynthetic rate and leaf water use efficiency of T2 weresuperior to that of other treatments, assimilation capacity of photosynthetic was strong, meanwhile, thewatermelon leaves of T2 could maintain an appropriate level of leaf cell sap concentration and intracellularwater metabolism. As a whole, under T2 intermediate frequency irrigation treatment, the watermelon plant grew well and the plant was robust at watermelon vegetative period, which had more advantages against adversitystress in early spring. Comprehensively considering soil moisture distribution, physiological and growth index,T2 irrigation frequency of once every 4 days under deficit irrigation condition was the optimum irrigationfrequency for watermelon growth at vegetative period in plastic greenhouse at early spring in northwest ofChina. This research could provide reference for the improvement of deficit irrigation water use efficiency atwatermelon vegetative period.