湖南主要土壤酸沉降敏感性初步研究

通过对湖南省主要土壤类型在模拟酸雨条件的敏感性大小进行研究，根据酸害阈值、酸害变化率等敏感性指标，对土壤敏感性进行比较发现，在酸雨pH值大于4．5时，处于土壤酸雨缓冲范围，而当酸雨pH值低于3．5或3时，土壤的pH值变化相当明显。不同土壤母质对酸雨的敏感性表现为：第四纪红土红壤＞砂岩红壤＞花岗岩红壤＞紫色砂页岩红壤；由于垂直地域分异作用，山地红壤的敏感生较大，其次为山地黄棕壤，山地黄壤为不敏感土壤；另外不同土层的敏感差异不明显，受耕作过的土壤酸缓冲性能明显增强。

A STUDY ON THE SENSITIVITY OF THE SOILS TO ACID PRECIPITATION IN HUNAN PROVINCE

The sensitivity of the soils in Hunan Province to the conditions of simulating acid rain is studied, where the indexes of pH, acid threshold and acid change speed are used. It is found that when pH value of the simulating acid rain is over 4 5,it lies in the buffer scope and the acid threshold and acid change speed change slowly. When pH value of the rain is below 3 5 or 3,the soil pH acid threshold and acid change speed change fast. The order of sensitivity of the soils developing on different parent material is: Quarternary red soil>Sandstone red soil>Granite red soil>Purple sandstone and shale red soil; Due to the effect of vertical zonality, the sensitivity of the mountain red soil is the highest, that of the mountain yellow brown soil the next, and that of the mountain yellow earth the least. The sensitivity of different horizons of soil differs less, and the cultivated land has evident buffer effect.