Abstract:

Using geostatistical and GIS methods,a case study on Dengxia catchment of hilly area in southern Jiangsu Province was conducted to examine the spatial variability characteristics of soil nutrients in the topsoil(0~20 cm).The indicators of soil nutrients included the pH,total nitrogen(TN),total phosphorus(TP)and available potassium(AK).The results showed:（1）The spatial variability of soil nutrients at the studied area was significant difference,and the variance coefficients followed the order of as total phosphorus>available potassium>total nitrogen>pH.The theoretical semivariogram model of pH was linear model,but TN,TP and AK of which all were exponential model.(2)The spatial distribution of pH and AK also was higher in the north part than that in the southeast,but there were several high value centers existing in the middle and south part just as small block,and they fluctuated acutely.The distribution of TN presented obviously beltshape and was higher in the north than in the southeast,with several lowest value centers embedding in the middle and south part of the area.But the distribution of TP was higher in the middle part than that in the north and southeast part,with several high centers embedding in the middle part.These results provide theoretical foundation for soil nutrients management and vegetation restoration in the studied area.

Key words: catchment/GIS/soil nutrients/spatial variability/hilly area in southern Jiangsu Province