典型喀斯特峰丛洼地坡面土壤养分空间变异性研究

Spatial variability of soil nutrients on hillslope in typical karst peak-cluster depression areas

采用线形取样,利用地统计学方法研究了典型喀斯特峰丛洼地坡面土壤养分的空间变异特征。结果表明:有机碳、全氮、碱解氮和速效钾具有相似的空间变异结构,其变程变化在212～251 m之间,与坡面不同土地利用方式的空间范围相当。全磷和全钾的变异尺度较小,为141.2 m和120.6 m。受部分耕地施用磷肥影响,速效磷的变异尺度最小,仅为85.1 m。除pH值外,土壤各养分均表现为强烈的空间相关性。有机碳、全氮、碱解氮等养分的空间分布表现出随着海拔高度增加而增大的特征,人类的耕作管理和峰丛洼地特殊的水文地质过程是影响土壤养分空间变异的主要因素。

The geostatistics method was used to determine and quantify spatial variability of surface soil nutrients （0-15 cm） in a typical Karst peak-cluster depression area in northwest of Guangxi province. Using line sampling method （10 m space）, 95 sampling points were fixed in total. Soil organic carbon （SOC）, total nitrogen （TN）, total phosphorus （TP）, total potassium （TK）, available nitrogen （AN）, available phosphorus （AP）, available potassium （AK）, pH value were measured. The results show that SOC, TN, AN and AK have the similar spatial variability structure, and their variability distances varied between 212-251 m, which corresponded to the average range of fields with the same land use types. TP and TK had relatively small variability distances of 141.2 m and 120.6 m, respectively. Due to the application of P-fertilizer, the variability distances of AP is the smallest in the research area. Excepted for pH value, all soil nutrients are strongly spatially dependent. The ordinary Kriging method shows that SOC, TN, AN content increases with the increasing of altitude, which indicate that the spatial pattern of soil nutrients on hillslope in typical Karst peak-cluster depression area is mainly controlled by hydrography conditions and land use types.