低分子量有机酸对石灰性潮土磷吸附与解吸的影响

采用磷的平衡吸附与解吸方法，模拟缺磷胁迫条件下植物根系分泌的有机酸种类和数量，研究了草酸、柠檬酸、苹果酸、酒石酸、乙酸5种有机酸对石灰性潮土磷吸附的影响，并以作用能力较强的草酸为代表，研究了有机酸对石灰性潮土磷吸附和解吸的影响。结果表明：（1）中性条件下供试有机酸均能不同程度的降低石灰性潮土对磷的吸附，作用强弱依次为草酸、柠檬酸＞苹果酸、酒石酸＞乙酸。（2）有机酸使土壤对磷吸附的降低效应随着有机酸浓度和有机酸与磷浓度比的增加而增加。（3）石灰性潮土在草酸体系中所吸附的磷容易被中性盐解吸，有机酸对土壤吸附磷的解吸有一定的促进作用。

Influence of low-molecular weight organic acids on phosphorus adsorption-desorption by calcareous Chao soil

Simulating the types and the concentrations of organic acids that plant roots excreted under phosphorus stress, the effects of oxalic, citric, malic, tartaric and acetic acid on phosphorus adsorption desorption by calcareous Chao soil have been investigated by equilibrium adsorption desorption method. Because the ability of oxalic is the strongest,so the influence of oxalic on desorption of P adsorbed by soil has been investigated.The results showed: (1) in the neutral condition , all these organic acids could reduce phosphorus adsorption by the soil, and the extent of reduction is closely correlated with the kinds of organic acids. The ability of organic acids to reduce phosphorus adsorption in calcareous Chao soil is in the order of oxalic, citric > malic, tartaric > acetic acid.(2) the extent of reduction increased with increasing concentration of organic acids and the concentration ratio of organic acids and phosphate. (3) the phosphate adsorbed by soil in the presence of oxalic acid was easy to be desorbed by neutral salt, and the organic acids could obviously strengthen the desorption of phosphate.