荒漠草原区土壤养分空间变异及评价

Spatial Variability and Evaluation of Soil Nutrients in Desert Savanes

采用经典统计学和地统计学相结合的方法,结合GIS技术,分析了宁夏红寺堡孙家滩园区（0～20 cm）土层土壤养分的空间变异特征,并运用普通克里格（Kriging）进行最优插值,制作了土壤碱解氮（AN）、速效钾（AK）、速效磷（AP）、全氮（TN）、全磷（TP）、有机质（OM）及pH的空间分布图.研究表明,速效磷变异系数最大为82％,pH变异系数最小为4％,变异系数由大到小依次为速效磷＞全磷＞全氮＞速效钾＞碱解氮＞有机质＞pH.各土壤养分都具有良好的半方差结构,pH、速效钾、全磷和有机质符合球状模型,碱解氮和速效磷符合线性模型,而全氮符合指数模型.在空间自相关范围上,全氮最大为37 750m,全磷最小为1 340 m.采用Kriging最优内插法对未测点进行了估值,绘制了等值线图,各种土样养分都在一定程度上受地形、土壤类型、土地利用方式、施肥等因素的影响,且均表现出明显不同的分布规律,土壤综合肥力水平较低.该研究揭示了孙家滩园区土壤养分的空间分布规律,对于实施精准农业和草地的可持续利用具有积极意义.

Using the methods combining traditional statistics and geostatistics together with GIS technology, the spatial vari- ability characteristics of the nutrients of the 0 - 20 cm soil at Sunjiatan park in Hongsipu in Ningxia were analyzed. The space distribution map of the soil alkali-hydrolysable nitrogen （AN）, available potassium （AK）, available phosphorus （AP）, to- tal nitrogen fiN）, total phosphorus （TP）, organic matter （OM） and the pH were made out by using Kriging for optimal interpolation. The results show that the coefficient of variation of the soil available phosphorus was the maximum about 82%, the variation coefficient of pH was minimum, namely 4%. The order of the variation coefficients is as follow from big to small： available p〉total p〉total nitrogen〉available potassium〉alkaline hydrolysis nitrogen〉organic matter〉pH. The various soil nutrients have good semi-variance structure, The pH, available potassium, total phosphorus and organic matter are in line with the spherical model, and the alkaline hydrolysis nitrogen and available phosphorus conforms to the linear model and the total nitrogen is in accordance with exponential model. As for the range of spatial autocorrelation, the total nitrogen is maximum, 37750 m and the total phosphorus is the minimum, 1340 m. The values of the no measuring points were esti- mated by using the Kriging optimal interpolation method and the contour map were draw. The nutrients of all kinds of soil are affected by the terrain, soil type, the way of land utilization and fertilization to some extent and they all show obvious different distribution. The comprehensive soil fertility level was low. The study reveals the law of the spatial distribution of the nutrient of the soil at Sunjiatan park and it has a positive significance to the implementation of the precision agriculture and the sustainable utilization of zrassland.