祁连山西水林区土壤发生特性及系统分类

Genetic characteristics and taxonomic classification of typical soil types in Xishui forest zone of Qilian Mountains, Northwest China

针对祁连山西水林区分布的4个典型土类(棕钙土、灰褐土、栗钙土及高山草甸土)进行了成土环境调查,通过剖面描述和样品分析明确了其发生特性,并据此检索出了各土类在我国现行土壤系统分类中的归属,为祁连山林区土壤特性的研究和土地资源的调查与评价提供了参考。结果表明:林区各土类土层较浅,具有粗骨性,山地特征明显;有机质累积较强,总体呈现高山草甸土>灰褐土>栗钙土>棕钙土;淋溶强度相对于湿润地区较弱,总体呈现高山草甸土>灰褐土≈栗钙土>棕钙土;风化强度总体较弱,不同土壤类型间差异不大;林区土壤剖面具有2类诊断表层、3类诊断表下层及4类诊断特性;棕钙土属于磐状钙积正常干旱土亚类,灰褐土属于钙积暗沃冷凉淋溶土亚类,栗钙土属于普通简育冷凉淋溶土亚类,高山草甸土属于普通简育湿润均腐土亚类。

An investigation was conducted on the soil-forming environment of four typical soil types （brown calcic soil, grey cinnamon soil, chestnut soil, and alpine meadow soil ） in the Xishui Forest Zone of Qilian Mountains, Northwest China. Through profile description and labo- ratory analysis, the genetic characteristics of the four soil types were studied, and their classifica- tion was identified according to the Keys to Chinese Soil Taxonomy, which could provide refer- ences for the researches of soil properties and the land resources survey and evaluation in the for- est areas of Qilian Mountains. The results showed that most of the sampled soil profiles were shal- low, and had obvious gravel/fragmental composition, with the characteristics of mountain soil. The organic carbon content in the four soil profiles was high due to the accumulation of organic matter. The alpine meadow soil had the highest accumulation of organic carbon, followed by grey cinnamon soil, chestnut soil, and brown calcic soil. The intensity of soil leaching was relatively weak, and soil eluviation was in the order of salpine meadow soil 〉 grey cinnamon soil ≈ chest- nut soil 〉 brown calcic soil. The physical and chemical weathering of the four soils was weaker, and the weathering degree had less difference among the soil types. The four soils had two diag- nostic surface horizons, three diagnostic subsurface horizons, and four types of diagnostic charac- teristics. In the classification system of Chinese Soil Taxonomy, the brown calcic soil was of Pan- Cal-Orthic Aridisols, grey cinnamon soil was of Cal-Mol-Boric Luvisols, chestnut soil was of Typ- Hap-Boric Luvisols, and alpine meadow soil was of Typ-Hap-Udic Isohumisols.