不同质地土壤的水分特征曲线参数分析

Analysis of parameters on soil water characteristic curves of different soil texture

对常用的土壤水分特征曲线模型进行了比选,选取Van Genuchten模型的4个参数进行了拟合计算,得到重壤土、中壤土、轻壤土、紧砂土和粗砂等5种不同质地土壤的水分特征曲线,分析了土壤水分特征曲线及参数的变化规律:粗砂的水分特征曲线变化最陡直,紧砂土、轻壤土、中壤土和重壤土的水分特征曲线变化较平缓;曲线的形状系数n随着粒径变大、物理性粘粒含量的减小而变大;重质粘性土壤α值较小,轻质土α值较大。

Comparisons of the common used models for soil water characteristic curves were made, and the best model was selected. Soil water characteristic curve for five different texture soils of heavy loam, medium loam, light loam, tight sand and rough sand was successfully sim- ulated with Van Genuchten equation. The variation tendency of soil water characteristic curve and its parameters were analyzed： water characteristic curve for rough sand changed sharply, but gently for tight sand, and light loam, and medium loam and heavy loam soils~ curve shape factor n become bigger as the particle sizes increased and the content of physical clay particle reduced~ alpha values for heavy clayed soil were found smaller larger for light soil.