一、试验目的 盘锦灌区防盐地下水适宜深度的研究是为辽河下游滨海盐碱土灌区排水设计和实行水旱轮作制中确定轮换年限提供科学依据。这对该地区经营管理上是极为重要的。 关于地下水适宜深度的研究,在国内外研究颇多,一般称为地下水临界深度。据国外文献报导,地下水临界深度的涵义可归纳为三种:一是土壤表层开始积盐的地下水最大埋深称为地下水临界深度;二是允许土壤轻度返盐,但返盐量不致危害作物正常生长 First, the purpose of the experiment Panjin Irrigation Groundwater suitable depth of the study is for the Liaohe River coastal saline soil irrigation drainage design and implementation of crop rotation system to provide a scientific basis for rotation. This is extremely important for the management of the area. Research on the suitable depth of groundwater has been studied many times at home and abroad, commonly referred to as the critical depth of groundwater. According to foreign literature reports, the critical depth of groundwater can be grouped into three types: First, the maximum depth of groundwater that accumulates salt on the surface of the soil is called the critical depth of groundwater; second, the soil is allowed to regurgitate lightly but the amount of salt returned is not harmful to crops Grow normally