长江中上游地区土壤崩解速率特征分析

Soil Disintegration Rate in the Upper and Middle Reaches of the Yangtze River

为分析长江中上游地区土壤崩解速率随土壤类型、剖面深度变化特征以及崩解速率的地域分异规律和主要影响因素,采用静水崩解法测定不同类型土壤的崩解速率,并对土样进行室内理化分析。结果表明:崩解速率随土壤类型不同由快至慢依次为砂质红壤、砂质黄壤、褐土、壤质黄壤、石灰土、紫色土、棕壤、壤质红壤;土壤崩解速率在垂直剖面上的变化趋势可分为递减型、递增型、凸峰型、凹谷型4种类型;陕南地区和湘东赣南山地丘陵区崩解速率最快,嘉陵江上游地区土壤崩解速率次之,丹江口库区、三峡库区、四川盆地和云贵高原等地土壤崩解速率较慢;影响长江中上游地区土壤崩解速率的主要因素是>0.25 mm的风干土水稳性团粒含量和有机质含量。

The aim of this research is to exploring the variation of soil disintegration rate with soil type and depth profile,as well as the regional heterogeneity of soil disintegration rate and its main impact factors in the upper and middle reaches of the Yangtze River.Hydrostatic disintegrating method was employed to test the disintegration rate of different types of soils and indoor physical and chemical analysis were carried out on the soil specimens.Results reveal that：the disintegration rate of sandy red soil is the largest,followed by sandy yellow soil,cinnamon soil, loam yellow soil,lime soil,purple soil,brown soil and loam red soil.The curves of disintegration rate variation a-long the vertical section can be classified into four types：descending,increasing,protruding and concave.The soil disintegration rate in the southern area of Shaanxi province and the mountainous and hilly areas in east Hunan and south Jiangxi are the highest,followed by the upper reaches of Jialing River,and the soil disintegration rate in Dan-jiangkou reservoir area,Three Gorges Reservoir area,Sichuan Basin and the Yunnan-Guizhou Plateau are relatively low.The water-stable aggregate content and organic content in weathered soil （〉0.25 mm）are the main factors affecting the soil disintegration rate.