新疆北疆荒漠草地土壤容重空间分布格局及其影响因素

针对我国荒漠草地土壤容重清查数据库严重缺失问题,以新疆北疆426个荒漠草地野外实测数据为对象,结合气象数据及“3S”技术,探讨土壤容重空间变异特征及其主要影响因素。结果表明:0~100cm各土层土壤容重变化范围为0.66~2.17g/cm 3,平均值为1.45g/cm 3,砾砂质、盐土、沙质、土质、砾石质荒漠亚类土壤容重均值依次为1.46、1.31、1.55、1.34、1.54g/cm 3。土壤容重随土层深度增加均呈增加趋势,表现出幂函数关系。荒漠土壤容重变异系数为10.06%~20.81%,呈现中等变异强度,其中砾砂质、砾石质和沙质荒漠土壤容重显著高于盐土与土质荒漠,且在空间分布上自东北向西南呈现降低趋势。荒漠草地土壤容重与经度、纬度、海拔、年均降水量、≥10℃年均积温、年均气温均极显著相关,且主成分分析将6个生态因子指标转化为3个复合指标,累计贡献率达到79.42%,其中年均降水量、≥10℃年均积温是北疆荒漠草地土壤容重空间变异的主要影响因子。

Spatial Distribution Pattern and Impact Factors of Soil Bulk Density in Desert Grassland of Northern Xinjiang

The spatial variation characteristics of soil bulk density and their impact factors were explored using meteorological data and“3S”technology based on a field survey of desert grassland(426 positions)in northern Xinjiang.The results showed that the bulk density variation of soil layer(0~100cm)was between 0.66 and 2.17g/cm 3 with an average value of 1.45g/cm 3.The average soil bulk density of gravel,saline,sandy,soil,and gravel desert subtype was 1.46,1.31,1.55,1.34 and 1.54g/cm 3,respectively.The soil bulk density was increased with the increasing soil depth.The bulk density variable coefficient of desert soil was between 10.06%and 20.81%.The bulk density of gravel sandy,gravel and sandy desert soil was significantly higher than that of saline soil and soil desert,and the spatial distribution showed a decreasing trend from northeast to southwest.The soil bulk density of desert grassland was significantly related to longitude,latitude,altitude,annual average precipitation,≥10℃annual accumulated temperature and annual average temperature,in which the annual precipitation and≥10℃annual accumulated temperature were the main impact factors.