Geostatistical Analysis of Horizontal Distribution of Soil Organic Matter in Guangdong, China

The spatial distributions of soil organic matter (SOM) in three horizontal soils in Guangdong, China, were surveyed and analyzed using geostatisitic and GIS. A total of 260 soil profiles data followed an approximately lognormal distribution. The soil organic matter geometric mean concentration of 2.76% in surface soils is higher than that in global soils. From A-to C- horizon soil organic matter geometric mean concentrations had a decreasing tendency of 2.76%, 0.96% to 0.66%. The ordinary kriging estimates of organic matter concentration were mapped. It showed higher local concentration around northern mount area. Soil organic matter distribution was mainly dependent on vegetation residues, anthropogenic inputs and bedrock properties. The anthropogenic impact is distinguished in local areas such as some big cities areas in B-horizon and C-horizon, where the soil organic matter concentration is higher than other area. The results showed a strong gradient of stock of soil organic matter around the northern mount area in A-horizon over 4%.