不同施肥条件土壤胡敏酸级分变异及性质的研究

VARIATIONS AND PROPERTIES OF SOIL HUMIC ACID FRACTIONS UNDER DIFFERENT FERTILIZATION CONDITION

摘要:

以17年长期定位试验土壤为材料,在研究土壤有机质氧化稳定性基础上,采用酒精沉淀分级方法,对不同施肥处理土壤胡敏酸的级分及光学性质进行了研究,并对胡敏酸及其级分的类型进行了划分。结果表明长期施用有机肥(堆肥及秸秆),土壤有机质含量明显增加,有机质的氧化稳定系数降低,土壤胡敏酸组成分布中心向高浓度酒精析出的级分偏移,颗粒小的级分比例增大;土壤胡敏酸的E₄、E₆值减小,E₄/E₆增大。而单施化肥则有相反趋势。土耕层土壤胡敏酸是由A、P和R_p三种类型级分所构成的混合物。施有机肥处理土壤胡敏酸以P型为主,R_p型也占有很大比例。不施肥或长期单施化肥处理则以A型为主。土壤胡敏酸的类型与其主要级分的类型保持一致。

Abstract:

Soil samples from a long-term spot experiment (17 years) with different treatments were used for studying the oxidation stability of soil organic matter and humic acid fractions by the alcohol precipitation technique, and the optical properties of humic acid and its fractions. Types of humic acid and its fractions were also classified. With applying organic materials (compost or corn straw) for a long time, soil organic matter content increased obviously, its oxidation stabilily decreased; the distribution center of soil humic acid fractions moved to the fraction precipitated by alcohol with a high concentration, and the proportion of fractions with a smaller partical size rose; E₄ and E₆ values of humic acid decreased and E₄/E₆ increased. Application of chemical fertilizer resulted in a contrary result.