关中平原台塬区土壤养分空间格局研究——以西安市长安区为例

Study on Spatial Distribution Pattern of Soil Nutrients in Guanzhong Plain——A Case Study in Chang'an District of Xi'an City

为研究关中平原台塬区土壤养分的空间分布情况,加强精准农业施肥管理,针对陕西省西安市长安区836.69km2范围内的土壤养分元素进行空间格局研究。通过GPS定位选取研究区内3 231个土壤采样点,测定了土壤样品的有机质、碱解氮、有效磷、速效钾以及pH值,并利用地统计法对其空间变异结构及格局现状进行研究。结果表明:土壤养分元素的变异系数范围为0.09～0.84,其变异程度依次为有效磷>速效钾>碱解氮>有机质>pH值;土壤有机质、碱解氮、有效磷、速效钾及pH值的变异函数曲线均符合指数模型;在空间结构上,土壤有效磷和有机质属于弱相关性,速效钾和碱解氮为中等强度相关性,pH值具有强烈的空间相关性;采用Kriging插值方法,可直观得到研究区域的土壤养分空间格局情况。

In order to increase the efficiency of applied fertilizers of precision agriculture and reveal spatial distribution characteristics of soil nutrients in Guanzhong Plain,a total of 3 231 points for soil sampling were selected in the area of 836.69 km2 in Chang＇an District of Xi＇an,Shaanxi Province.The soil nutrient indices including available phosphorous（AP）,available potassium（AK）,available nitrogen（AN）,soil pH and organic matter（SOM） were analyzed with classic statistics and geostatistics method.The results indicated that the variability coefficients of soil nutrients ranged from 0.09 to 0.84 and the order of the variation degree was AP〉AK〉AN〉SOM〉pH.The semi-variograms of SOM,AN,AP,AK and pH were best described by exponential model.Those soil properties had different spatial correlations respectively,pH had the significant spatial correlation,AK and AN had the moderate spatial correlation,and AP and SOM had the weak spatial correlation.Spatial distribution pattern of soil nutrients in the study area could be obtained by using Kriging interpolation.