论文部分内容阅读
目前国内在水利工程的规划设计中,灌区灌溉用水计算,一般是分别计算各种作物在各个生长阶段的净灌溉定额,用净灌溉定额乘作物面积得净灌溉用水量.净灌溉定额是用作物各生长阶段的需水量减有效降水量求得.常规的方法在确定作物各生长阶段的需水量时考虑当时土壤水分条件和蒸散发能力的影响不够,甚至未考虑,因而由此计算出的作物各生长阶段需水量与各年作物的实际蒸散发量有很大差别.作物各生长阶段的需水量是作物散发量和棵间蒸发量的总和(即蒸散发量),而蒸散发量又与作物的供水条件(旱作地可用土壤含水量来代表)及蒸散发能力(受气象条件制约)有密切关系,这两种因素在不同的年份差别很大.根据山东省冶源、石马等灌区的试验资料,冬
At present, in the planning and design of water conservancy projects, the calculation of irrigation water in the irrigation area generally calculates the net irrigation quota of various crops at each growth stage separately, and the net irrigation quota multiplies the net irrigation water consumption by the crop area.The net irrigation quota is calculated as crop The water requirement of each growth stage is reduced by the effective precipitation.The conventional method can not consider the soil moisture condition and evapotranspiration at the time of determining the water demand of each growth stage of the crop, The water demand in each growth stage is greatly different from the actual evapotranspiration of crops in each year. The water demand of crops at each growth stage is the sum of the crop and evapotranspiration (evapotranspiration), while the evapotranspiration Crop water supply conditions (available soil moisture in dry land to represent) and evapotranspiration ability (subject to weather conditions) are closely related, these two factors vary greatly in different years.According to Shandong Province, Irrigation test data, winter