黄土高原西北部砂田西瓜集雨补灌效应研究

在黄土高原西北部地区对砂田西瓜的集雨补灌效应进行了研究。试验采用滴灌方式，设0mm(D0)、22．5mm(D1)、45．0mm(D2)和67．5mm(D3)4个灌水量处理。区组内各处理随机排列，四次重复。试验结果表明：在西瓜全生育期，每个处理0～120cm土层的土壤水分含量均呈下降趋势，下降的幅度随着补灌量的增加而减小。全生育期补灌67．5mm的处理土壤含水量最高，比没有补灌的对照处理高2．2％。土壤水分的变化在0～40cm土层比较活跃。其次是40～80cm土层，而80～120cm土层的含水量变化相对比较稳定。对砂田西瓜进行补灌可以提高产量和水分利用效率。补灌45mm和67．5mm的处理比对照分别增产36．3％和45．7％。补灌67．5mm处理的水分利用率最高，为26．7kg／m^3。比对照增加17．0％；该处理的净利润和每单位(m^3)水的净利润也最高，分别达43．677元／hm^2和18．48元／m^3，比不补灌的对照处理高29．9％和15．3％。补灌量对西瓜的含糖量也有影响，补灌量低于45mm，各处理之间含糖量的差异不大，补灌量为67．5mm，西瓜含糖量降低0．44％。补灌对西瓜的产量、含糖量和水分利用率均有影响，砂田西瓜只有补灌量控制在45mm左右，才能既提高产量和水分利用率，又不降低西瓜品质。

Effect of supplemental irrigation with harvested rainwater on w atermelon (Citrullus lanatus) production in gravel-and-plastic mulched fie lds in the Loess Plateau of Northwest China

Trials were conducted to examine the effects and ec onomic feasibility of supplemental drip irrigation on watermelon production in g ravel and plastic mulched fields in the Loess Plateau of northwest China in 20 01. The trial comprised four levels of supplemental drip irrigation: 0mm, 22 5 mm, 45 0 mm and 67 5 mm. The treatments were laid out in two complete randomiz ed blocks with 4 replications. The precipitation during the experiment, which co vered the watermelon growing period was 125 8 mm. The r...