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通过两年的田间试验,研究了滴水量和滴水频率对膜下滴灌棉田土壤水分分布及棉花水分利用效率的影响.结果表明:从整个生育期来看,当滴水量(375mm)相同时,高频滴灌(每3天1次)处理0～20cm土层含水率较高而深层土壤湿润不够;低频滴灌(每10天1次)处理有利于水分的下渗和侧渗,深层土壤含水率较高,但水分补给不及时,表层土壤偏低;总体上中频滴灌(每7天1次)处理有利于水分在土壤剖面中的均匀分配.当滴水频率相同时,滴水量越大,土壤含水率越高,40cm以下土层含水率也越高.不同处理的棉田耗水规律基本一致,苗期较低,平均不高于1.7mm.d-1,蕾期开始上升至花铃期达到最高,日均耗水量可达8.7mm.d-1,吐絮期回落到1.0mm.d-1左右.总耗水量与降水和滴水量密切相关,而与滴水频率无关;滴水频率对棉花水分利用效率无显著影响,但水分利用效率随滴水量的增大而显著降低.少量滴灌(300mm)虽然可以获得较高的水分利用效率,但减产严重,过量滴灌(450mm)无显著增产效应,水分浪费严重.在当地棉田自然条件下,采用中量(375mm)+中低频(每7天或10天1次)的滴灌模式为宜.
After two years of field experiments, the effect of drip irrigation and drip irrigation frequency on soil water distribution and cotton water use efficiency was studied. The results showed that when the drip irrigation (375 mm) was the same Frequency drip irrigation (once every 3 days) treatment 0 ~ 20cm soil moisture content is higher and the deep soil moisture is not enough; low-frequency drip irrigation (once every 10 days) is conducive to water infiltration and lateral infiltration, deep soil moisture content than High, but the water supply is not timely, the surface soil is low; Generally, medium frequency drip irrigation (once every 7 days) is conducive to the uniform distribution of water in the soil profile.When the dripping frequency is the same, the greater the drip capacity, the soil moisture content The higher the water content of soil under 40cm, the water consumption law of cotton fields under different treatment is basically the same, the seedling stage is low, the average is not higher than 1.7mm.d-1, the bud stage begins to rise to reach the highest, The daily average water consumption was up to 8.7mm.d-1, and the boll opening time was down to about 1.0mm.d-1. The total water consumption was closely related to precipitation and drip irrigation, but not to the drip irrigation frequency. The drip irrigation frequency had no significant effect on the water use efficiency of cotton However, water use efficiency decreased significantly with the increase of dripping water Irrigated area (300mm) could obtain high water use efficiency, but the yield was severely reduced. No significant stimulation effect was produced by excessive drip irrigation (450mm), and the water was wasted seriously.Under the natural conditions of local cotton fields, 7 days or 10 days 1) drip irrigation mode is appropriate.