衡山土壤的粘粒矿物

衡山的土壤,随着海拔高度的增加,依次分布着成土过程由强到弱的红壤、山地黄壤和山地草甸土.这个规律在粘粒矿物的组成上得到较好的反映.从山脚到山顶高岭石渐减,而三水铝石渐增.埃洛石则普遍存在,但以B,C层为多.风化程度较低的次要矿物如水云母、水黑云母、14(Å)过渡矿物和绿泥石等也是衡山的上部较多.从粘粒矿物组成的特点判断,衡山上部不存在山地黄棕壤,而只有山地黄壤和山地草甸土.衡山上部土壤的三水铝石含量很高,以致粘粒的硅铝率甚小.三水铝石可能是斜长石的直接风化产物.由这种方式产生的富铝化现象,在发生学上有别于热带土壤的富铝化作用.

CLAY MINERALS OF THE SOILS ON HENGSHAN MT.

The genetic process of the soils on Hengshan Mt.in Hunan province are getting stronger with the increase of the altitude,and the vertical sequence of the soils from the mountain foot to the summit is in the order of red earth,mountain yellow earth and mountain meadow soil.This regularity is well reflected in the constituents of the clay minnrale of the soils.It was found that the quantity of kaolinite decreased and that of gibbsite increased with the increase of the altitude.however,hallaysite existed in almost all the soils,especially in layer B and C horizons.The weak-weathered clay minerala such as hydromica,hydrobiotite,and chlorite mainly exist in the soils on upper hart of the mountain.