黄土丘陵沟壑区土壤微量元素空间变异特征及其影响因素

以安塞县为研究区,运用地统计学和GIS技术相结合的方法研究了黄土丘陵沟壑区土壤中有效态Fe、Mn、Cu和Zn的空间变异特征及其影响因素。结果表明:四种微量元素的变异系数在14.81%～22.49%之间,都属于中等变异性;块金效应值在11.76%～46.94%之间,Zn的空间相关性较强,Fe、Mn和Cu的空间相关性中等;各微量元素含量在空间分布上呈现出由北部和南部向中部递减的趋势。土壤类型对Mn和Cu的含量有显著影响,灰褐土中Mn和Cu的含量高于黄绵土。相对高程与Fe、Mn和Zn呈极显著负相关;坡度与Mn和Cu呈显著或极显著负相关;地形起伏度与Fe和Cu呈显著或极显著负相关。有机质、碱解氮、有效磷和速效钾与Cu呈显著或极显著负相关,与Zn呈极显著正相关;速效钾与Fe和Mn呈极显著正相关;pH值与各微量元素均呈显著或极显著负相关。

Spatial variability and controlling factors of soil trace elements in hilly and gully area of the Loess Plateau

With Ansai County as the study area,geostatistics combined with geographical information system(GIS) technique were applied to analyze the spatial variability and controlling factors of soil available Fe,Mn,Cu and Zn in hilly and gully area of the Loess Plateau.The result indicated that: the variation coefficient of these soil trace elements was between 14.81% and 22.49%,and every trace element had medium variability;The nugget effect value was between 11.76% and 46.94%,and the spatial correlation of Zn was highly dependent,while Fe,Mn and Cu were moderately dependent;The spatial distribution of the content of each trace element showed a diminishing trend from north and south to the central area.The soil type remarkably influenced the contents of Mn and Cu,indicating that their contents in gray-cinnamon soils were higher than those of loessial soils.The relative elevation(Hr) had highly significant negative correlation with Fe,Mn and Zn;Gradient(β) had significant or highly significant negative correlation with Mn and Cu;Roughness of terrain(QFD) had significant or highly significant negative correlation with Fe and Cu.Organic matter,available nitrogen,available phosphorus and available potassium had significant or highly significant negative correlation with Cu and highly significant positive correlation with Zn;Available potassium had highly significant positive correlation with Fe and Mn;pH had significant or highly significant negative correlation with each soil trace element.This study provided basis and reference for reasonable fertilization and soil environmental protection in this area.