采用取土烘干称重和负压计测读相结合的方法 ,测定无水层时轻壤土和高沙土区稻田根层土壤含水率的消退过程 ,并与相应的地下水埋深建立相关关系 ,其间大致呈幕函数的变化规律。运用该关系曲线 ,即可按土壤含水率占饱和含水量的百分比推算确定稻田灌水下限的地下水埋深指标。大面积推广水稻节水灌溉技术时 ,灌水下限指标就用地下水埋深表示 ,实际操作将比较简单 ,适应当前农村的管理水平 The combination of soil drying weight and negative pressure measurement was adopted to determine the subsidence of soil water content in the root layer of light-loam soil and high-sandy soil layer under the condition of no water layer, and to establish the correlation with the corresponding groundwater depth, In the meantime, the change of the curtain function is roughly the same. Using this relationship curve, we can calculate the groundwater depth index for determining the lower irrigation limit of paddy field according to the percentage of soil moisture content as the percentage of saturated water content. Large-scale promotion of rice water-saving irrigation technology, the minimum irrigation targets on the groundwater depth indicators that the actual operation will be relatively simple to adapt to the current level of rural management