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降雨有效利用量是指能够参与一定深度土层水分活动和提供作物生理生态需水的降水量,包括小雨和大雨两部分,有效雨量是进行农业规划、灌区设计、作物配置、分配水量和拟定灌溉制度的重要参数。影响降雨有效利用的因素很多,除降雨强度、过程、分布外,还与气候、土壤、作物、地形、地下水及土壤水分等条件有关,现根据生产实践和观测资料加以分析。(一)小雨量的有效利用50年代曾以小于5 mm 降雨作为无效雨量,近年又以小于3mm 为无效量。但从生产实践中观察看出:1.小雨量对作物生育有明显作用。作物生长期间,当土壤水分不足时,天气晴朗,作物则发生萎蔫;遇到阴天,作物萎蔫缓解;倘有微雨,作物则恢复生机。说明微小
Effective use of rainfall refers to the ability to participate in a certain depth of soil water activity and provide crop physiological and ecological water requirements of precipitation, including light rain and heavy rain two parts, the effective rainfall is carried out agricultural planning, irrigation design, crop allocation, allocation of water and irrigation System of important parameters. There are many factors that affect the effective utilization of rainfall. In addition to rainfall intensity, process and distribution, it is also related to climate, soil, crops, topography, groundwater and soil moisture, and is now analyzed based on production practices and observations. (A) Effective Use of Light Rainfall Less than 5 mm of rainfall was used as an ineffective rainfall in the 1950s and less than 3 mm in recent years. However, we can see from the production practice that: 1. The rainfall has a significant effect on crop growth. During the crop’s growing season, when the soil moisture is not enough, the weather is sunny and the crop wilting. When it encounters overcast weather, the crop wilts to relieve the wilting effect. If there is light rain, the crop will regain its vitality. Description tiny