不同植被下黏质红壤水分特征曲线研究  

Water Characteristic Curves of the Clayey Red Soil Under Different Vegetation Types

作　　者：于元芬 郭明先 孟飞 宋婧[1] 林丽蓉[1] YU Yuan-fen;GUO Ming-xian;MENG Fei;SONG Jing;LIN Li-rong(College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China)

机构地区：[1]华中农业大学资源与环境学院,武汉430070

出　　处：《节水灌溉》2020年第9期69-74,共6页Water Saving Irrigation

基　　金：国家自然科学基金项目(41601220)。

摘　　要：为分析不同植被下黏质红壤的持水、释水及孔隙特性,用离心机法测定了鄂南一个典型红壤坡地的8种植被地块(3种树龄的杉树、茶树、红叶石楠、无患子、油菜、桂花树)4个深度(20、40、60、90 cm)的土壤水分特征曲线,进而计算了土壤不同孔隙度,用Van Genuchten模型(VG模型)拟合水分特征曲线数据,同时获得土壤比水容量曲线。结果表明:①VG模型能够较好地拟合黏质红壤的水分特征曲线,决定系数R2在0.9814~0.9994之间;②土壤持水能力的变化主要出现在低于500 kPa的土壤水吸力范围内,土壤释水过程大多发生在低吸力范围内(0~500 kPa)。试验坡地的土壤总孔隙度是40.4~47.0,其中毛管孔隙度约为39.2,而有效孔隙度仅为15.0左右,因此土壤水分有效性整体较差;③持水能力最好的是茶树、大杉树和小杉树3个地块,多数地块的表层土壤较深层土壤有更好的排水能力,但深层土壤的持水能力强于表层土壤。研究坡地的土壤虽然属于同一种类型土壤,但不同植被、不同深度的土壤持水能力、释水特性及水分有效性存在一定差异,在分析红壤坡地水分动态分布规律时应考虑在内。In order to investigate the soil water retention,water release and pore characteristics of the clayey red soil under different vegetation types,centrifuge technique was used to measure the soil water characteristic curves(SWCCs)of the soils collected on a typical clayey red soil slope in southern Hubei province.Soil sampling was conducted at four soil depths(20,40,60 and 90 cm)in eight plots separately under three different tree ages of Chinafir,tea plant,photinia glabra,soapberry,rape,osmanthus.Different types of porosities of the soil were calculated based on the SWCCs.The Van Genuchten model(VG model)was used to fit the measured SWCCs data and then the soil specific water capacity curves were obtained.The results show that:①The VG model can well fit the soil water characteristic curve of the clayey red soil,and the determination coefficient R2 is between 0.9814 and 0.9994;②The changes of soil water-holding capacity mainly occur in the range of soil water suction below 500 kPa,and the processes of soil water release mostly appear in the range of low suction(from 0 to 500 kPa).The total soil porosities of the experimental slopes are from 40.4%to 47.0%,with a mean capillary porosities of 39.2%and a mean effective porosity of 15%.Therefore,the overall soil water availability is poor;③Lands under tea plant,old Chinafir(10 years of tree age)and young Chinafir(5 years of tree age)have the best water-holding capacity.The surface soils in most plots have better drainage capacity than those in deep soils,but the water-holding capacities in deep soils are stronger than those of surface soil.Differences in soil water-holding capacities,water release characteristics and water availabilities occur at various depths under different vegetations in the study sloping land.This phenomenon should be taken into account when analyzing the soil water dynamics in the clayey red soil sloping land.

关 键 词：红壤 Van Genuchten模型 水分特征曲线 比水容量 孔隙度 

分 类 号：S152.7[农业科学—土壤学] TV93[农业科学—农业基础科学]