论文部分内容阅读
灌溉措施的很重要任务是经济而合理地利用灌溉水。减少地面径流、渗漏和地表蒸发,以提高灌溉效益。为了使用保墒灌溉技术措施,必须掌握土壤水量平衡各组成部分的测定方法,其中蒸发量的测定尤为重要。目前测定旬、月蒸发量广泛地利用计算方法,这种方法多属于经验性的,不能认为是十分满意的。水量平衡法测定短时期蒸发量,其困难在于必须精确计算土壤上下层的水分交换和蒸腾。在实践中普遍采用各种类型和大小不同的蒸发器来直接测定蒸发量,但由于蒸发器内土柱与自然土壤隔绝,因而器内土柱的水、热状况与自然土壤有别;特别是在有作物覆
An important task of irrigation measures is the economical and rational use of irrigation water. Reduce surface runoff, seepage and surface evaporation to improve irrigation benefits. In order to use technical measures of soil moisture conservation, it is necessary to know the determination methods of each component of soil water balance, of which the determination of evaporation is especially important. Currently measured ten, monthly evaporation widely used method of calculation, this method is mostly empirical and can not be considered very satisfied. Water balance method to measure short-term evaporation, the difficulty lies in the accurate calculation of soil moisture exchange and transpiration. In practice, various types and sizes of evaporators are commonly used to directly measure the evaporation. However, since the soil columns in the evaporator are isolated from the natural soil, the water and heat conditions in the soil columns in the device are different from the natural soil; in particular, In the crop cover