城郊耕层土壤养分的空间变异特征

Spatial Variability of Soil Nutrients in Guangzhou Suburb

以广州郊区岑村为例，采用GIS与地统计学相结合的方法对城郊耕层土壤（0—20cm）的有机质、全N、全P和全K4种土壤养分要素的空间变异特征进行了分析。结果表明：有机质、全N和全K变异函数曲线的最优理论模型为指数模型；全P为球状模型。几种土壤养分具有很强的空间相关性，异质性特征。各土壤养分由随机因素引起的空间变异占空间总变异的比例小，其值分别为9.90％、8．80％、0．26％和17．10％。说明受母质、地形、土壤类型等自然的结构性因素影响较大。土壤特性的相关距变化范围为139．00—750．00m。该成果可为城郊农业的定位施肥、灌溉以及其它的农田精细管理提供依据。

Spatial variability of nutrients in the surface layer （0- 20cm） of suburb soils from Cencun in Guangzhou was studied using GIS, GPS technique and geostatistical analysis. The result showed that Semivariograms of soil organic matter, total N and total potassium （K） were well fitted by an exponential model, while semivariogram of total phosphorus（P） was fitted by a spherical model. The ratios of random variance （nugget） to total variance were low. These values were 9.90% for soil organic matter, 8.80% for total N, 0.26% for total K and 17. 10% for total P respectively. It was found that spatial heterogeneity of all soil nutrients was great, because the spatial variabilities of all soil nutrients were primarily controUed by structural factors of parent material, relief and soil types. And the range of soil properties correlation distance was 139.00 -750.00m. All these results could serve as a basis for precision fertilization, irrigation and management in suburb farms.