Abstract:

In order to discover the content and spatial variability of purple soil nutrients in southwest China and to make proper fertilization recommendations adapted to the local conditions, the author combined geostatistics with GIS to analyze the spatial variability of soil nutrients in topsoil (0-20 cm) in Tongliang, Chongqing. The results showed that the mean of available N, available P, available K and Organic matter were 105.86 mg/kg, 7.19 mg/kg, 81.31 mg/kg and 22.89 g/kg, respectively, and they were all in middle or low level. Soil pH was mainly around 6.5, which indicated that the soil was acidic. The coefficient of variation of available P was 77.61%, which was the highest among the five nutrients, followed by available K, organic matter and available N, and they all expressed medium variability. While the soil pH was more stable whose coefficient of variation was 17.78%. The spatial interpolation figure indicated that the content of available N was mainly centralized between 114.42-148.39 mg/kg, and the content of available P was lower than 14.35 mg/kg, with the lowest value was 1.00 mg/kg. The distribution of available K showed no regularity and the content of available K in about half of the area was between 60.56-74.82 mg/kg, followed by 79.83-94.09 mg/kg. The content of organic matter was mainly centralized between 15.27-33.77 g/kg and soil pH in most area was between 5.2 to 6.5, which could be another proof to the conclusion that the soil was acidic.