渍害田地下排水设计指标的研究
Present Status and Prospect of Study on the Subsurface Drainage Criteria
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摘要: 在降水集中的湿润平原地区,由于地下水位过高,引起土壤过湿,作物受到渍害威胁。为了提高作物产量需要修建排水系统,降低地下水位。在采用稳定流方法进行排水设计时,常以允许最小地下水埋深和相应排水系数作为设计指标,在用非稳定流方法设计时,多根据一次降水后允许的地下水位降速作为排水设计指标。随着计算机的发展,地下水动态计算日益方便,在作物产量与地下水动态关系的基础上,提出了采用作物生长期或生长阶段地下水动态作为指标的多种形式,如累积超标深度SEWx、抑制天数指标SDI、累积减产指标CRI等。对渍害田排水设计指标的研究现状及展望进行了论述。Abstract: Due to high standing of water table in plain areas with concentrated rainfall the crops often suffer from waterlogging,with the aim of increasing crop production it is required to construct drainage systems for water table control.In this paper the present status and prospect of study of drainage indexes and criteria used in subsurface drainage design,such as minimum permissible water table depth,the designed rate of water table drawdown after a rainfall event,the cumulative excess water depth SEWx in the growth period of crops,the stress day index SDI and the cumulative yield reduction index CRI etc are reviewed.