陕西省洛川县第3-4层黄土和古土壤水分特征研究

Soil Moisture Characteristics of Third and Fourth Horizons of Loess and Paleosols in Luochuan County of Shaanxi Province

通过对陕西省洛川县第3—4黄土层和第3—4红色古土壤层的原状土进行水分特征曲线、田间持水量等项目的实验测定,分析计算了各层土壤的供水储水性能及有效水分含量。结果表明,洛川第3—4黄土层和第3—4红色古土壤土层的水分特征曲线与Van Genuchten模型非常符合,相关系数R2均达0.99以上,说明采用Van Genuchten模型对这4个土层的水分含量和能量之间的关系进行描述是比较准确的。0～30kPa吸力条件下,第3—4黄土层比第3—4红色古土壤层持水量高,黄土层的供水(释水)性能和储水性能强于古土壤。这4个土层随着吸力的增加,在较低吸力段供水性能和储水性能减弱幅度较大,在较高吸力段减弱幅度较小。黄土层所能容纳的有效水含量、饱和含水量与田间持水量均大于红色古土壤层,黄土层的稳定凋萎湿度一般小于红色古土壤的稳定凋萎湿度。

Based on determination of soil water retention curves and field moisture capacity of intact soil sam- ples of Loess and Paleosols in Luochuan County, Shaanxi Province, the study analyzed the physical soil prop- erties including soil moisture storage, holding capacity and effective moisture content. The results indicate that the water retention curves of soil samples could be described well with Van Genuchten model with the high R2 values（over 0.99）. The water holding capacity of the loess samples were higher than that of the Pal- eosol samples in the range of 0 to 30 kPa, suggesting that loess performs better in water supply and storage. With increasing suction values, water supply and storage reduced with larger amplitude in low suction range and smaller amplitude in high suction range. Loess showed higher available water content, saturated water content and field holding capacity, and lower permanent wilting point than paleosol.