用土柱淋溶实验研究水杨酸对酸性土壤铝迁移的影响

选择2种可变电荷土壤和1种酸性恒电荷土壤用土柱淋溶实验研究了水杨酸对土壤铝迁移的影响。结果表明，不同土壤由于矿物组成的差异，它们对有机酸的吸附容量有很大的不同，因此有机酸对不同土壤中铝的迁移有不同的影响。富铁土游离氧化铁的含量低于铁铝土，它对有机酸的吸附量也低于铁铝土的，因此在淋溶实验初期，有机酸对铝迁移的影响较小，在淋溶实验后期，由于土壤对有机酸的吸附达饱和状态，有机酸对铝的迁移表现出很强的促进作用，特别在有机酸初始浓度较高的情况下。铁铝土含有大量铁、铝氧化物，对有机酸有很高的吸附容量，有机酸对这类土壤铝迁移的影响很小。淋溶土对有机酸的吸附量很小，当有机酸的初始浓度较高时，淋溶实验开始后不久，有机酸就对铝的迁移表现出明显的促进作用。实验结果还表明，铝的迁移还与体系pH有关，低pH条件有利于土壤铝的溶解和迁移。

STUDY ON EFFECT OF SALICYLIC ACID ON MIGRATION OF ALUMINUM IN ACID SOILS WITH LEACHING EXPERIMENT

Two variable charge soils and one acid constant charge soil were chosen to investigate the effect of salicylic acid on migration of A1 with leaching experiment. The results showed that the different soils had different adsorption capacity for salicylic acid due to the difference in soil mineral compositions, and thus the effect of salicylic acid on the migration of A1 in different soils was different. The Ferralosols with high content of free iron oxides has the great adsorption capacity for salicylic acid and thus small promotion of the acid on migration of A1 was observed in this soil. The content of free iron oxides in Ferrosols was lower than that in Ferralosols, the adsorption capacity for salicylic acid in the former was also smaller than that in the latter. Therefore at the earlier stage of leaching experiment, the effect of salicylic acid on migration of A1 was small, but the great promotion was observed in the soil at the latter stage of leaching experiment, especially at high initial concentration of salicylic acid. The Argosols has small adsorption capacity for salicylic acid, the organic acid showed obvious promotion on A1 migration in the soil at high initial concentration of the acid after the start of leaching experiment. The results also indicated that the migration of AI was also related to the pH of soil systems. Low pH promoted the dissolution of A1 and the migration of A1 in soils as well.