区县域尺度土壤全氮的空间分布格局分析

Spatial distribution patterns of soil total nitrogen at a county scale

以赤峰市敖汉旗为研究对象,以实测数据为基础,采用地统计学与典范对应分析相结合的方法研究县域尺度土壤全氮的空间分布格局及其影响因素。结果表明:0-100 cm深度土壤全氮含量在0.43-0.68 g/kg范围变化,土壤全氮平均含量随着土壤深度的增加而降低,其水平分布均呈现为南高北低的分布特征,低值区集中呈片状分布在研究区的东北部,高值区呈岛状分散于研究区的南部区域。各层土壤全氮均属于中等强度的空间相关性,随着土壤深度的增加,随机因素对全氮空间变异的影响作用逐渐减弱,其空间最大自相关距离也随着土壤深度的增加而逐渐减小。各环境因素对土壤全氮含量的影响程度由高到低表现为海拔>NDVI>粘粒含量>土壤容重>坡度,土壤粘粒和NDVI与表层土壤的相关性更高,海拔对60 cm以下土壤全氮的影响更加显著。

The spatial variability and distribution patterns of total nitrogen content in 0-100 cm deep soil were analyzed to determine the dominant factors affecting the spatial variability of total nitrogen content in different soil depths in Aohan County. The analyses were based on soil survey data, geostatistics, and canonical correspondence analysis. The results showed that the variation range of total nitrogen content was 0.43--0.68 g/kg in 0-100 cm soil depths, and the total nitrogen content decreased gradually with increasing soil depth. Obvious differences between North and South were found. A moderate spatial correlation of total nitrogen was found in 0-100 cm soil depths. With increasing soil depth, the spatial variability caused by random factors gradually decreased, and the spatial autocorrelation distance of total nitrogen decreased gradually. The effects of environmental factors on soil total nitrogen content from high to low were as follows: elevation > normalized difference vegetation index(NDVI) > clay content > soil bulk density > slope, in which soil clay and NDVI had higher correlations with surface soil, and elevation had a more significant effect on soil total nitrogen below 60 cm soil depths.