北京市大兴区土壤肥力的空间变异

该文旨在揭示北京市大兴区土壤肥力指标及肥力质量空间变化规律，为土壤培肥管理提供指导。通过实测研究区土壤有机质、全氮、速效磷、速效钾和pH值五个肥力指标的含量，运用地统计学方法和Fuzzy综合评判法对其进行计算分析。结果表明：大兴区5种土壤肥力指标中，有机质、全氮、速效钾、pH值的块金值与基台值的比值C0/(C+C0)分别为0.38、0.25、0.29和0.50，说明它们具有中等的空间相关性；速效磷的C0/(C+C0)达到0.88，说明其具有弱的空间相关性；土壤有机质和全氮含量主要由北向南逐渐降低，速效磷主要从西南向东北方向逐渐降低，速效钾主要由东南向西北方向逐渐降低，pH值主要由南向北逐渐降低；大兴区土壤肥力质量呈现出明显的北高南低的趋势，5个等级地块分别占全区总面积的0.21%、6.35%、20.95%、29.45%和43.04%，Ⅲ类、Ⅳ类、Ⅴ类等地占整个区域面积的93.44%。大兴区土壤肥力总体水平偏低，除了与该地区土壤质地偏砂有关，同时也受到人为管理措施的影响。

Spatial variability of soil fertility in Daxing District of Beijing

The objective of this study was to explore the spatial variability of soil fertility indices and soil fertility quality, and to provide guidance for soil fertilization management. Soil indices selected included soil organic matter, total N, available P, available K and pH value. Geostatistics method and fuzzy comprehensive evaluation method were used to analyze the data. The results showed that the C0/(C+C0) of organic matter, total N, available K and pH value were 0.38, 0.25, 0.29 and 0.50, respectively, which demonstrated moderate spatial dependence. The C0/(C+C0) of available P was 0.88, which demonstrated weak spatial dependence. Soil organic matter and total N decreased from north to south; available P decreased from southwest to northeast; available K decreased from southeast to northwest; pH value decreased from south to north. The fertility quality of Daxing District decreased from north to south. The five categories of fertility quality covered 0.21%, 6.35%, 20.95%, 29.45% and 43.04% of the total area, respectively. The third category, fourth category and fifth category covered 93.44% of the total area. The fertility quality of Daxing District was generally low, which was affected by soil texture and artificial cultivation management.