有机质和游离铁对湘南红壤表面电荷性质的影响

用双氧水破坏土壤有机质和用DCB（连二亚硫酸钠／柠檬酸钠／重碳酸钠）脱铁等方法研究湘南第四纪红粘土及其发育的土壤的表面电荷性质．结果表明：去除土壤有机质．使红壤胶体表面的阴离子交换量（AEC）增加、可变负电荷量（CECV）降低，在多数情况下其永久负电荷量（CECP）增加；脱游离氧化铁使红壤AEC减少、CECp增加，CECV增减不一．笔者认为，这与土壤胶体组分之间的相互作用有关．

Effect of Soil Organic Matter and Free Iron Oxide on Surface Electric Charge Characteristics of Quaternary Red Soils in Southern Hunan

The present paper deals with the contribution of organic matter and hydrous oxides to surface charges of quaternary red soils in southern Hunan. Results of the experiments show that the contribution of organic matter to variable negative charge (CECv) and the contribution of free iron oxide to anion exchange capacity (AEC) of those soils are both positive, while that of organic matter to AEC and that of free iron oxide to permanent negative charge (CECp) of the soil are negative.However, contributions of free iron oxide to CECv of those soils may be positive or negative, which is considered by the auther to be relevant to counteractions of different colloid components of those soils.