南方典型土壤水力特征差异性分析

为探究南方地区典型土壤水力性质的差异,采用压力膜法、定水头渗透法和一维水平土柱吸渗法对粘性潮土、沙性潮土、红壤、水稻土和紫色土5种南方典型土壤的水动力学参数进行室内测定,对比分析了各土壤水力特征的差异及其产生的原因。结果表明:土壤质地和粘粒含量是影响土壤水力特征的主要因素;粘性潮土、沙性潮土属于级配良好土,而红壤、紫色土、水稻土属于级配不良土,粘性潮土、沙性潮土、红壤、紫色土、水稻土饱和导水率依次增大,分别为1.75×10~(-3),3.15×10~(-3),4.77×10~(-3),11.02×10~(-3),11.87×10~(-3) cm/min;相对水稻土和沙性潮土而言,其他3种试验土持水性较高。土壤有效水含量为沙性潮土粘性潮土水稻土紫色土红壤,其有效水孔隙体积分别占其总孔隙体积的48%,29%,27%,18%和17%。非饱和条件下,沙性潮土和红壤中的水分运动速率较快,远高于粘性潮土中的水分运动速率,约为其6.8倍。土壤质地、颗粒级配、粘粒和有机质含量不同是造成土壤水力特性差异的因素,其中土壤质地和颗粒级配为南方典型土壤水力特性差异的主要影响因素。

Difference Analysis of Hydraulic Characteristics of Typical Soils in South China

Soil hydraulic properties are important factors affecting hydrologic processes on soil surface and efficiency of irrigation and drainage.The aim of this study was to explore the differences in soil hydraulic properties in South China.The pressure membrane method,the constant head seepage method,one-dimensional horizontal soil column were used to measure the hydrodynamic parameters of five typical soils (clay fluvoaquic soil,sandy fluvo-aquic soil,red soil,paddy soil,and purple soil) in South China.The differences in soil hydraulic characteristics and the reasons for the differences were compared and analyzed.The results were as follows:Soil texture and clay content were the major factors affecting soil hydraulic characteristics.Because the clay fluvo-aquic soil and sandy fluvo-aquic soil were well graded soil,while red soil,purple soil,and paddy soil were poorly graded soil,the saturated hydraulic conductivity followed the order of clay fluvoaquic soil＞sandy fluvo-aquic soil＞red soil＞purple soil＞paddy soil,being 1.75 × 10 3 cm/min,3.15 × 10-3 cm/min,4.77 × 10-3 cm/min,11.02 × 10-3 cm/min and 11.87 × 10-3 cm/min,respectively.The water holding capacity of the sandy fluvo-aquic soil,red soil,and purple soil were higher than that of the paddy soil and sandy fluvo-aquic soil.The available water content followed the order of sandy fluvo-aquic soil＞clay fluvoaquic soil＞paddy soil＞purple soil＞red soil,the effective water pore volume accounted for 48％,29％,27％,18％ and 17％ of the total pore volume,respectively.Under the unsaturated condition,the water movement speed of the sandy fluvo-aquic soil and red soil were much higher than that of the clay fluvo-aquic soil,which was 6.8 times of that of the clay fluvo-aquic soil.Soil texture,particle size distribution,clay and organic matter content were factors contributing to the differences in the hydraulic properties of typical soils in South China,and soil texture and particle size distribution were the main influential factors.