鄂湘两省山地土壤粘粒矿物的研究──Ⅲ．神农架自然保护区北坡土壤的粘粒矿物与表面化学特性

STUDIES ON CLAY MINERALS OF MOUNTAIN SOILS IN HUBEI AND HUNAN PROVINCES──Ⅲ.CLAY MINERALS AND SURFACE CHEMICAL CHARACTERISTICS OF SOILS ON NORTH SLOPE OF SHENNONGJIA NATURAL CONSERVATION AREA

本文研究结果表明：（１）神农架垂直带土壤矿物的风化脱硅作用较弱，粘土矿物以２：１型矿物为主，１：１型高岭含量很少。（２）随海拔升高，矿物的淋溶脱钾和层间羟基铝化作用增强，低海拔土壤的２：１型矿物以水云母为主，高海拔土壤以１．４ｎｍ矿物为主，其中１．４ｎｍ过渡矿物相对增多。（３）土壤的络合态铁、铝和非晶形铁，铝含量随海拔升高明显增大。（４）土壤的可变电荷量，阴离子交换量，交换性酸和铝饱和度等均随海拔升高而提高，非晶形铁，铝对土壤表面化学特性的影响增大。根据土壤粘粒矿物的固相组成和该区的生物气候条件，分析讨论了神农架山地土壤粘粒矿物的风化与成土作用特点。

In the five types of soils on the north slope of the Shennongjia Natural Conservation area, 2:1 type clay mineral was predominant,and there were few kaolinites. There existed a weak desilicification in the soils.For the yellow-brown soil and mountain yellow-borwn soil, the main clay mineral was hydromica,and there was a certain amount of vermiculite, as well as a few 1.4nm intergrade minerals and kaolinites.In the mountain brown soil, mountain dark brown soil and mountain brown coniferous forest soil,1.4nm minerals(being mostly 1.4nm intergrade mineral) were the major clay minerals,arid there were certain amounts of hydromica and chlorite and a few kaolinites or vermiculites. For soils examined,the higher the sampling site,the stronger the eluvial depotassification process of clay mineral in soil was.The contents of various noncrystalline iron, aluminum oxide,increased obviously with increasing altitude in the area. The enrichment of noncrystalline iron and aluminum in case of higher altitude, which could play a main role in influencing the surface properties of soils,resulted mainly from the leaching losses of base and silica under the conditions of low temperature,high moisture and the complex or chelation eluviation of organic acid.