鄂西北山区耕层土壤全氮空间变异及自相关分析

Spatial variability and autocorrelation analysis of topsoil total nitrogen in mountainous areas of northwestern Hubei province

土壤全氮含量(STN)与耕地质量密切相关,掌握STN的空间分布特征对增强区域STN的精准管理及耕地质量提升具有重要意义。根据鄂西北山区十堰市701个耕层土壤样点数据,采用地统计学方法结合Moran’s I指数进行空间自相关分析,探讨十堰市STN的空间自相关类型及其空间分布格局。结果表明:研究区STN的平均含量分别为1.118 mg/kg,变异系数为49.374%,变程为321600 m,具有中等强度的空间自相关。空间变异受结构因素影响较大,在0°(N-S)方向的空间变异最为剧烈。STN含量整体上呈现从南向北逐渐递减的分布格局。全局自相关表明研究区STN存在较强的空间正相关特征,且不同方向存在差异;随着距离的增大,STN呈现负相关特征,分布存在空间孤立。局部空间自相关系数为0.3576,主要类型为L-L型和H-H型,空间集聚特征明显。

Soil total nitrogen is closely related to cultivated land quality.To master the spatial distribution characteristics of soil total nitrogen is of great significance for enhancing the accurate management of regional soil total nitrogen and improving cultivated land quality.Based on the data of 701 topsoil samples in Shiyan city,northwest Hubei province,the spatial autocorrelation of soil total nitrogen was analyzed by geostatistical method and Moran’s I index,and the spatial autocorrelation type and distribution pattern of soil total nitrogen in Shiyan city were discussed.The results show that the average content of STN in the study area is 1.118 mg/kg,with a coefficient of variation of 49.374%and a range of 321600 m,showing moderate spatial autocorrelation.Spatial variation is greatly influenced by structural factors,with the most severe spatial variation occurring in the 0°(N-S)direction.The overall distribution pattern of STN content is gradually decreasing from south to north.Global autocorrelation indicates that the STN in the study area has strong spatial positive correlation characteristics,and there are differences in different directions.As the distance increases,STN exhibits negative correlation and spatial isolation in distribution.The local spatial autocorrelation coefficient is 0.3576,and the main types are L-L and H-H,with obvious spatial clustering characteristics.