中卫市压砂地土壤有机质空间变异特点研究

Spatial Variability of Soil Organic Matter in Gravel-mulched Land of Zhongwei City

通过野外采集土样,获取研究区不同空间尺度的有机质数据,运用经典统计学、地统计学结合GIS的方法,分析中卫市压砂地土壤有机质的空间变异特点。统计分析表明:区域尺度土壤有机质含量为1.64~14.66 g kg^(-1),田间尺度土壤有机质含量为2.73~6.17 g kg^(-1),均属中等程度变异。中卫市压砂地土壤整体处于缺乏水平(<1.0%),地统计结果表明:区域尺度土壤有机质有中等的空间自相关性,其中,接近中下水平(1.0%~1.5%)的区域位于沙坡头区的西南部,向四周逐渐降低。在沙坡头区的中部、海原县的东北部形成了两个有机质极缺的地区(<0.6%)。而处于缺乏水平(0.6%~1.0%)的区域分布范围最广,主要分布在中宁县的东北和西南部,沙坡头的东部以及海原县的中部和西北部。田间尺度的土壤有机质有强烈的空间自相关性,分布相对比较均匀,在其西部偏低,偏高值地区分布零散,无规律。

Soil organic matter（SOM） had important significance to soil physical function, chemical action and biological function. It was useful to investigate the basic condition of SOM, comprehensively and scientifically understand the evolution rule of soil fertility, and ensure sustainability using in gravel-sand mulched fields. This paper collected the data at different spatial scales from gravel-mulched fields and analyzed the data using the general statistics and geostatistics combined with GIS methods. The statistic analysis results showed that the content of SOM was 1.64- 14.66 g kg^-1at regional scale and was 2.73- 6.17 g kg^-1at field scale. And their variation belonged to moderate level. As a whole, SOM content belonged to deficient level（ 〈1.0%） in Zhongwei City. Geostatistical analysis results showed that SOM at large scale had moderate spatial autocorrelation. The SOM belonged to lower-middle level（1.0%- 1.5%） was mainly distributed in the southwest of Shapotou District. SOM content gradually decreased around.And the lowest level（〈 0.6%） was in the middle of Shapotou District and the northeast of Haiyuan County and the lower level（0.6%- 1.0%） was the most widely distributed in the northeast and southwest of Zhongning County, the east of Shapotou District and the middle and northwest of Haiyuan County. The SOM distribution at field scale had the characteristics of very strong spatial autocorrelation and relatively uniform distribution. The lower value was mainly found in the west region and the higher value distribution was scattered and had no rules.