青藏高原石膏寒漠土的发生特点  

SOIL-FORMING CHARACTERISTICS OF GYPSIC FRIGID DESERT SOILS EN THE QINGZHANG PLATEAU

作　　者：顾国安[1] 张累德[2] 

机构地区：[1]中国科学院南京土壤研究所 [2]中国科学院新疆生物土壤沙漠研究所

出　　处：《土壤学报》1991年第2期196-201,共6页Acta Pedologica Sinica

基　　金：国家自然科学基金

摘　　要：寒漠土分布于我国青藏高原西北部的高寒荒漠带,它是在冰冻过程制约下形成的荒漠土壤,具有颗粒粗、粉粒和铁在表层(亚表层)聚积、有机质积累少等发生特征。石膏寒漠土除有上述特征外,还有石膏强烈聚积,因此,它通常有三个基本发生层:(1)孔状结皮层,厚度1—4厘米,多孔、呈片状或鳞片状;(2)铁质化紧实层,位于结皮层之下,厚度3—5厘米,游离铁,活性铁和粘粒含量高于上下土层,块状结构;(3)石膏层,厚度10—20厘米,石膏含量12—25%,最高达40%,结晶形态良好。根据寒漠土中具有典型的石膏层这一发生特征,拟划分出石膏寒漠土亚类。Frigid desert soils belong to desert soils formed under freezing conditions which are distributed in the high and cold desert zone of the Northwest Qingzhang plateau with genetic features of coarse particles,silt enrichment,iron accumulated in surface or subsurface horizon and low O. M.content,etc.Besides,gypsum obviously accumulated in gypsic frigid desert soils.In general,there are three basic genetic horizon:1) vesicular crust horizon,with a thickhess of 1——4 cm and many pores, and being plate or squamose-shaped;2) ferric compact horizon under vesicular crust horizon, with a thickhess of 3—5 cm,contents of free iron,active iron and clay being higher than those of its uDper and lower horizons and blocky in structure;and 3) gypsic horizon,with a thickness of 1O—20 cm,gypsum content of 12——25% even 40%somewhere and good crystallization.Thus,gypsic frigid desert soils are classified as a subgroup of frigid desert soils according to the presenge of typical gypsic horizon.

关 键 词：青藏高原 石膏寒漠土 发生特点 

分 类 号：S155.34[农业科学—土壤学]