针对草地、保护地、菜地和茶园4种不同土地利用方式的土壤进行了4个压力水头(-9、-6、-3和0 cm)、2个不同盘径的圆盘入渗试验。结果表明,在本试验条件下,不同盘径的圆盘入渗仪测定结果差异不显著,小盘径圆盘更适合用于野外测定土壤水力特征参数。随着水头的减小,4种土地利用方式的土壤稳定入渗率和土壤非饱和导水率呈不同程度的减小。4种土地利用方式土壤的水力学性质差异显著,根据实测资料确定了不同负水头下的土壤饱和导水率和Gardner指数模型参数α,土地利用方式对土壤导水率和Gardner指数模型参数α均有显著影响。不同土地利用方式下土壤大、小孔隙对水流的贡献率影响显著,中等孔隙1、中等孔隙2对水流贡献率影响不显著。茶园和草地各级土壤孔隙对水流的贡献率随孔隙尺寸减小而降低,而菜地和保护地小孔隙(孔隙半径0-0.1 mm)对水流的贡献率为最高。
Based on the infiltration experiments using two size-disc infihrometers, the characteristics of the soil hydraulic properties at four different pressure heads ( - 9, - 6, - 3, and 0 cm) were analyzed under four land uses. The results showed that the infiltration rates were not obviously different tested by infiltrometers with different diameter discs. The infiltrometer with small disc was more suitable for the field determination of soil hydraulic properties. With the decreasing of the pressure head, steady infiltration rates of the 4 soils decreased to different extents. Soil hydraulic conductivity and Gardner were determined according to the experimental data at different negative water pressure heads, which were obviously different with land uses. Land use had significant effects on the contributions of macropores and micropores to flow. The contribution of each class pore to flow was reduced with the decrease of the pore size under tea garden and grass land. However, the contributions of micropores ( 〈0. 1 mm) to flow were kept the highest level in vegetable field and protected field. The result could provide references for estimating hydraulic parameters of soils in hilly area of South China.