WATER-SOLUBLE ORGANIC MATTER IN SOIL UNDER CHINESE FIR AND MASSON PINE FOREST

Abstract

In order to understand the behavior of water soluble organic matter (WSOM) in soil under different types of forest, soil samples from twenty sites were sampled and analyzed for each forest in the area of Huzhou, China. Each sample was extracted with both cool water (25°C) and hot water (100°C). Without exception, hot water soluble organic carbon (HWSOC) was more than cool water soluble organic carbon (CWSOC). Chinese fir forest soil contained 1.49 times more CWSOC and 1.34 times more HWSOC than did the masson pine forest soil. The CWSOC and HWSOC in soil under Chinese fir forest account for 1.11% and 1.60% of total soil organic carbon (TSOC), and 0.70% and 1.19% under masson pine forest soil, respectively. CWSOC under Chinese fir forest was closely related to SOM and microbial biomass carbon (MBC) (correlation coefficients were 0.474* and 0.482* respectively), HWSOC, however, has little to do with SOM, MBC and soil enzymatic activities. HWSOC under masson pine forest was generally associated with SOM, MBC and sucrase, urease and protease (correlation coefficients were 0.511*, 0.510*, 0.541*, 0.418*, 0.356, respectively), but CWSOC was only closely related to sucrase (0.560*) and protease (0.581* *). It is concluded that higher amount of WSOC under Chinese fir forest is not good for soil chemical and biological properties.