水耕年限对黄棕壤发育的水稻土的表面化学性质的影响

Effects of Cultivation Periods on Surface Chemical Properties of Paddy Soils Derived from Yellow Brown Soil

利用采自江苏省农业科学院果园的旱地黄棕壤(对照)和由黄棕壤发育水耕20年和60年的水稻土,研究了土壤黏粒和粉粒的矿物组成,胶体和土体的化学性质随水耕年限的变化。粉粒的X-射线衍射图谱表明,3种供试土壤发育母质相似,胶体的矿物组成随水耕年限的变化不大。动电电位和表面负电荷的测定结果也表明,胶体表面化学性质未发生明显变化。随水耕年限增加,土壤黏粒含量降低,导致土体性质发生明显变化,土壤CEC和结构电荷量随水耕年限增加显著减少。

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.