寻乌县耕地土壤全氮含量空间变异特征及其影响因素

Spatial Variation and Its Influencing Factors of Soil Nitrogen in Cultivated Land of Xunwu County

以寻乌县耕地质量与产能评价试点项目采集的耕地表层土壤(0~20 cm)数据为例,采用地统计分析和回归分析等方法,对该区域耕地土壤全氮的空间变异特征及其影响因素进行研究和分析。统计结果表明,寻乌县耕地表层(0~20 cm)土壤全氮含量在0.42 g kg^(-1)~2.25 g kg^(-1)之间,均值为1.21 g kg^(-1),变异系数为26.88%,处于中等程度的空间变异;从半方差分析的结果来看,块金效应为62.50%,表明随机性因素对研究区土壤全氮的影响程度要大于结构性因素;从空间分布来看,寻乌县土壤全氮的分布总体上呈现出北低南高的趋势,且大致呈条带状和块状分布,全氮含量较高的耕地分布较为零散,且面积不大,而含量较低的耕地主要分布在中部及北部部分地区。回归分析表明,成土母质对土壤全氮有着极显著的影响(P<0.01),土壤类型、耕地利用方式对土壤全氮的影响均达到了显著水平(P<0.05);地形因素对土壤全氮含量的独立解释能力最高,为7.3%,是影响寻乌县耕地土壤全氮含量空间变异的主要因素。

Soil data of cultivated land were collected from the project of cultivated land quality and productivity evaluation supported by the Natural Resources Department of Xunwu County, and the spatial variability of soil total nitrogen(TN) was analyzed by the methods of semi-variance analysis, ordinary Kriging and regression analysis. This study also analyzed the impact factors on the spatial variation of soil TN. The statistical results showed that the TN contents of soils(0-20 cm) in Xunwu County were 0.42-2.25 g kg^(-1), with a mean value of 1.21 g kg^(-1) and a coefficient of variation of 26.88%, which was moderately spatially variable. From the results of semi-variance analysis, the nugget effect was 62.50%, indicating that soil TN in the study area was more affected by random factors than by structural factors. The contents of soil TN were generally lower in the north and higher in the south of Xunwu County, and showed roughly the strip-like and patchy distribution. The area with high contents of TN was scattered and small, and that with low contents of TN were mainly distributed in the central and the north of Xunwu County. The regression analysis of various factors showed that soil parent material had a significant effect(P < 0.01) on soil TN. The effects of soil type and land use on soil TN were significantly different(P < 0.05), and topographic factor had the highest explanatory capacity for soil TN, which was 7.3%. So topography was the main factor affecting the spatial variation of soil TN in the cultivated land of Xunwu County.