甘肃河西地区不同储水灌溉和生育期灌溉农田水分特征分析

Analysis of soil water characteristics of farmland under different winter storage irrigation in Hexi Region of Gansu Province

对甘肃河西地区不同储水灌溉和生育期灌溉农田水分特征进行了试验研究。结果表明：在河西地区,冬季储水灌溉定额为180 mm的处理,其生育期剖面的土壤水分较多地分布在140-160 cm,且土壤含水量达到30%以上,容易发生深层渗漏;较小的储水灌溉定额,土壤水分主要分布在0-100 cm范围内,不会引起土壤剖面水分的深层渗漏。冬季储水灌溉定额愈大,春播前农田无效土壤蒸发也愈大。冬季储水灌溉定额相同,生育期灌溉定额大的处理其剖面含水量高,且分布愈深,深层土壤的水分渗漏也愈大。总的灌水定额相同,冬季储水灌溉和生育期灌溉比较,生育期灌溉定额较大的处理,剖面水分的分布主要集中在0-100 cm的土层内,没有出现易发生深层渗漏较高的水分分布。在小麦生育期,总的灌溉定额相同的条件下,冬季储水灌溉定额大的处理,0-200 cm土壤水分有亏缺,冬季储水灌溉定额大或生育期灌溉定额大,农田腾发量也愈大。适中的储水灌溉定额,不仅有利于作物的生长,还有利于灌溉水分利用效率的提高。

The soil water characteristics of farmland under different winter storage irrigation in Hexi Region of Gansu Province were analyzed. The results showed that profile soil water distribution of farmland was mostly in 140- 160 cm layers with the treatment of 180 nmm winter storage irrigation ration, and the soil water content of the layer was above 30 %, easy to occur leakage in the deep soil layer. In the relative small ration of storage irrigation, profile soil water distribution of farmland was mostly in 0 -100 cm layers, unlikely to occur leakage in the deep soil layer. There was large invalidation soil water evaporation with the higher ration of the winter storage irrigation. In same winter storage irrigation ration, the more irrigation ration in wheat growth period, the more soil water content and deeper layer soil water distribution and deeper soil water leakage occur. In same irrigation ration of experimental period, comparatively with winter storage irrigation, the large ration crop period irrigation treatment had a soil water distribution in 0 -100 cm soil layer, and the results also showed no soil water leakage occurrence. In the same total irrigation ration of experimental period, there was a water deficit in 0 -200 cm soil layer with the treatment of large volume shortage irrigation. It had showed that there was a higher evapotranspiration occurrence when having a higher winter storage irrigation ration or larger irrigation ration in growth period. With the appropriate storage irrigation ration, it could not only better crop growth but also increase irrigation water use efficiency.