半干旱农牧交错区土壤养分空间变异特征分析——以内蒙古伊金霍洛旗为例

本文以伊金霍洛旗为研究区,通过GIS平台对土壤养分中的有机质、全氮、速效钾的空间插值方法进行了比较并得到了最优插值图。然后分析了该旗土壤养分的空间分布规律,为该地区的农业生产布局和生态环境建设提供了依据。通过比较后认为,在该地区有机质的空间插值用反距离权重法为好,而全氮和速效钾的空间插值以克吕格法的指数模型和高斯模型为好。地统计学分析结果表明:有机质、全氮和速效钾的变程分别为11853m,8932.2m和732.99m,全氮和速效钾具有中等空间相关性,而有机质空间相关性较弱。有机质含量普遍偏低,在91%的面积中有机质含量低于10g/kg,其相对高值区呈离散分布,可能与隐域植被的分布有关。全氮含量与有机质含量分布相似,在70%的面积中低于0.75g/kg,而速效钾含量中等,介于102.04-103.31mg/kg之间。在三个不同的景观亚区中,乌审凹地亚区的土壤养分状况较好,黄土丘陵亚区养分状况最差,毛乌素沙地亚区介于它们之间。

Spatial Variability Analysis on Soil Nutrients in Semi - Arid Agro - Pastoral Transition Area——A Case Study in EjinHolo Banner, Inner Mongolia

Ejin Holo Banner in the west of the Inner Mongolia Autonomous Region,China,is a typical semi-arid agro-pastoral transition area.In this paper,a case study on comparing different methods of interpolation and finding the best prediction map were carried on in Ejin Holo Banner based on the application of GIS.Then the spatial variation of soil nutrients was analyzed because it was the foundation of planning agricultural position and environmental reconstruction.Comparing the prediction values with actual values, Inverse Distance Weighted for soil organic matter(O.M),exponential model of Ordinary Kriging for total nitrogen(Total.N) and Gauss model of Ordinary Kriging for soil available K(Avail K) was respectively the best method for their interpolations.Geo-statistical analysis showed that the spatial autocorrelation ranges of O.M,Total.N and Avail.K were 11853m,8932.2m and 732.99m.And the ratio of nugget and sill indicated that the spatial autocorrelation of Total.N and Avail.K was medium.However,the spatial autocorrelation of O.M was weak.The prediction map of O.M showed that its content was low(<10g/kg) in 90% of areas,and the areas with relative high value were scattered,the cause of which was related with peculiar topography.The distributions of total nitrogen and soil organic matter were analogical.The content of Total.N was low(<0.75g/kg) in 70% areas,but the content of Avail.K was universal medium(102.04-103.31mg/kg).In three subregions,the order on the situation of soil nutrient was Wushen Lowland subregion >Mu Us Sandland subregion >Loess Hill subregion.