Micro-scale Spatial Variance of Soil Fertility Indices in the Rubber PlantationI: 0～20 cm Soil Layer

The objective of this study was to explore the micro-scale spatial variance of soil fertility indices in the rubber plantation.168 soils were sampled by 0.5 m×1 m grid within a 84 m2 region.Soil fertility indices selected included total N,available P,available K,soil organic matter and pH.Geostatistics method was used to analyze the data.Results showed that the semi-variance of the total N,available P,available K,soil organic matter and pH could be simulated by the exponential model.The ranges for total N,available P,available K,soil organic matter and pH were 1.44 m,1.65 m,3.36 m,1.20 m and 1.74 m.The geostatic analysis showed these soil indices were strongly heterogeneity.The distributions of soil fertility indices were obviously different.Contour maps of total N,available P,soil organic matter showed as a island of fertility.Area of the island of total N was the biggest,soil organic matter was in the following,available P was the smallest.The contour maps of available K showed relatively uniformity,which may be related to the parent material of the soil.