苗儿山土壤的矿物组成

苗儿山海拔2142m,年降水量较高,植被繁茂,土壤母岩主要为花岗岩,局部杂有砂页岩、千枚岩和板岩。从山脚到山顶,依次分布着成土过程由强到弱的山地红壤、山地黄壤、山地黄棕壤和山地灌丛草甸土。其相应的粘粒矿物为2:1型矿物逐渐增加,高岭石不断减少。所有土壤都出现埃洛石和三水铝石,后者在剖面中有由下往上减少的倾向。14A过渡矿物多分布在山的中部消下土壤中。混层矿物出现普遍。 花岗岩发育土壤原生产矿物的风化指数,从山脚到山顶逐渐变小。本文还讨论了三水铝石的转化条件,并对土壤富铝化与土壤风化、红壤化的关系提出初步看法。

THE MINERAL COMPOSITION OF SOIL IN MIAOER MOUNTAIN

Miaoer mountain,the altitude of which is 2142 meters,is covered with dense vegetation due to abundant annual rainfall.The soils in that mountain developed mainly from granite and partly from arenaceous shale,phyllite and slate in some areas.The genetic process of soil in Miaoer mountain gets weaker with increase in altitude.The vertical sequence of soils from the mountain foot to the summit is in the order of mountain red earth,mountain yellow earth,mountain yellow-brown earth and mountain shrubby meadow soil.Corresponding to the vertical sequence ofthe soils,the quantity of 2:1 type mineral increases and that of kaolinite decreases gradually.Halloysite and gibbsite exist in all soil profiles and the latter tends to increase with the increase of depth.14A intergradient mineral is found mainly in the soils at about a little below the middle of the mountain where a mixed layer of mineral commonly occurs.The weathering index of the primary mineral in the soil developed from granite gets less with the increase in altitude.The conditions for the transformation of gibbsite are dealt with in this paper,and the relation among soil allitization,soil weathering and red earthening is also presented.