一、农田排水系统的作用农田排水工程是降低过高的地下水位和防治或改良土壤盐碱化的重要措施。对于盐碱土地区来说,其主要任务是:排除土壤中过量的对作物生长有害的水及盐分,加速地下水的降落过程及脱盐过程,把地下水位控制在某一适宜的深度,以保证作物的正常生长及防止土壤返盐。对于低洼沼泽地区来说,其主要任务是:降低过高的地下水位,以控制在某一适宜的地下水位深度;在规定的时间内,使地下水位下降到某一容许高程;在入渗作用下,保证地下水位不超过最大上升高度。以上这些要求,即为设计明沟或暗管沟深、沟距的依据。二、农田排水系统的设计指标 First, the role of farmland drainage system Farmland drainage project is to reduce excessive groundwater levels and prevention or improvement of soil salinization an important measure. For the saline-alkali soil area, its main tasks are: to eliminate excess soil water and salt harmful to crop growth, accelerate the groundwater descent process and desalination process, the groundwater level control in a suitable depth to ensure that the crop Normal growth and prevent the soil back to salt. For low-lying marshy areas, the main tasks are: to reduce the excessively high groundwater level to control the depth of a suitable groundwater level; to reduce the groundwater level to a certain allowable elevation within a specified time; Under, to ensure that the groundwater level does not exceed the maximum increase in height. These requirements above, that is, the design of open ditch or hidden ditch deep, the basis of the gap. Second, farmland drainage system design indicators