地中仪地膜棉灌溉试验特征分析

利用不同地下水埋深的地中仪进行地膜棉的灌溉试验，分析了地膜棉不同生育期时蒸发、入渗的变化特征：受地膜棉的蒸腾作用，灌溉入渗量随其日耗水量增加而显著减少；棉花根系吸水影响深度与其日耗水强度成指数关系，其根系吸水最大影响深度为2．76m；棉花根系利用地下水量随埋深增加而减小，棉田最佳的灌水湿润深度应小于1．0m，当灌水湿润深度超过1．5m时，其根系不能更多利用地下水，即可认为是深层入渗。

Analysis on Irrigation Characteristic of Cotton under Film through Lysimeter

Using lysimeter, through irrigation experiment for cotton under film in different groundwater depth, the variation charac teristic of evaporation and infiltration of cotton under fihn in different growth period was analyzed in this paper. The result showed that because the influence of transpiration of cotton, the infiltration amount of irrigation water decreased remarkably with the in crease of water consumption of cotton. The influence depth of cotton roots absorbing water had an exponential relationship with the intensity of cotton consuming water, and the maximal depth was 2. 76m. The amount of groundwater utilized by cotton decreased with the increase of groundwater depth. The best wetting depth of irrigation water must be less than 1 m. If the wetting depth of irrigation water was more than 1.5 m, cotton roots could not utilize the water and it could be regarded as infiltration lost.