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为探明小流域土壤养分特性空间变异规律及其与环境因子的关系,以非均匀取样方法测定了黄土高原水蚀风蚀交错带小流域土壤表层(0～10、10～20、20～40cm)的硝态氮和铵态氮,采用经典统计和地统计学方法分析了其空间分布特征及变异结构。结果表明:土地利用空间配置成混合利用结构拦截和减少径流侵蚀,形成了土壤矿质氮坡面斑块镶嵌格局。小流域内硝态氮和铵态氮呈中等的空间变异和自相关性,其变异性由土壤系统内部因素包括土壤质地、矿物、成土过程、地形特征和人类活动造成的外部因素包括施肥和耕作等共同控制。建立了土壤矿质氮多元回归预测模型,各回归模型的自变量不同,表明不同土层硝态氮和铵态氮的变异受不同环境因子控制。分析认为合理配置土地利用形成斑块状结构和增加养分投入可以改善研究区土壤质量。
In order to find out the spatial variation of soil nutrient characteristics and its relationship with environmental factors in a watershed, the heterogeneous sampling method was used to determine the soil surface (0-10, 10-20, 20-40 cm) in the watershed of the wind-water erosion crisscross region on the Loess Plateau Nitrate nitrogen and ammonium nitrogen, the spatial distribution and variation structure were analyzed by classical statistics and geostatistics methods. The results show that the land use space is configured to intercept and mix with the structure to reduce the runoff erosion and form the mosaic pattern of soil mineral nitrogen slope. Nitrate and ammonium nitrogen in small watershed showed medium spatial variability and autocorrelation. The variability was caused by internal factors in soil system including soil texture, mineralogy, soil forming process, topographical features and human activities including fertilization and Tillage and other common control. The multivariate regression model of soil mineral nitrogen was established. The independent variables of the regression models were different, indicating that the variation of nitrate nitrogen and ammonium nitrogen in different soil layers was controlled by different environmental factors. The analysis shows that the rational allocation of land use to form a patchy structure and increase nutrient input can improve soil quality in the study area.