Effects of cultivation periods on surface chemical properties of paddy soils derived from yellow brown soil
水耕年限对黄棕壤发育的水稻土的表面化学性质的影响

The mineralogical and surface chemical properties of two paddy soils and one yellow brown soil and their colloids were investigated to elucidate the effects of water cultivating period on these properties of the soils. The soils were collected from the experimental plots in Jiangsu Academy of Agricultural Sciences. The results showed that there were tiny differences of mineral compositions in silt fractions among three soils, suggesting that the investigated soils developed form homogeneous parent materials. The electrokinetic potential and negative surface charge of soil colloids did not change with the age of rice cultivation significantly, which indicated that the surface chemical properties of colloids were similar for these soils. However, the clay fraction for paddy soils decreased with the age of rice cultivation. Subsequently, the soil properties changed markedly. Both CEC and the values of structural negative surface charge decreased with the age of rice cultivation significantly.