中文摘要：

以聚丙烯酰胺（PAM）与磷石膏（PG）为土壤结构改良剂，利用离心机法，测定土壤水分特征曲线，从分析土壤的吸水能力和持水能力的角度出发，研究土壤结构改良剂对土壤水分有效性的影响。研究结果表明，土壤的吸水能力、持水能力与释水能力均表现出与用量密切相关；在使用土壤结构改良剂的情况下，仍然可用van Genuchten方程很准确的模拟土壤吸力与含水率之间的关系，即可作为使用土壤结构改良剂后的土壤水分特征曲线的模拟表达式；在试验的用量范围内，土壤结构改良剂的使用不会影响植物对水分的吸收和利用。

英文摘要：

The mixture of PAM and PG were taken as soil conditioner here. Centrifuge method was used to measure soil water characteristic curve, through analyzing water absorbing ability and water retention ability of soil to inve tigate the influence of soil conditioner on soil water availability. The results show that soil water absorbing ability, water retention ability and water discharging capacity were all related with the dosage of PAM and PG intimately. The relationship between soil suction and soil moisture, that is soil water characteristic curve, was still be simulated by van-Genuchten equation accurately. In the range of PAM dosage, water absorption and utilization of plant will not be influenced by soil conditioner.