有机酸对土壤磷吸附的影响

Effect of Organic Acids on Soil Phosphate Absorbing Capacities

以棕红壤为对象，采用等温平衡吸附法，研究了不同有机酸种类和浓度对土壤磷吸附的影响。结果表明：不同种类的有机酸、其功能基（－ＣＯＯＨ，－ＯＨ）数目多的对降低土壤吸磷量的影响大，供试五种有机酸的影响大小顺序为：柠檬酸＞草酸＞酒石酸＞苯甲酸＞乙酸；在同一ｐＨ下，随加入有机酸浓度的升高，土壤吸磷量减少；有机酸与磷的不同加入方式对磷吸附量的影响也不同，先吸附磷后再加入有机酸的吸磷量最大，吸附有机酸后离心弃去有机酸液再加入磷的吸磷量次之，吸附有机酸后再加入磷的吸磷量最小。

It was studied that the effect of different kinds of organic acids and their concentrations on the soil phosphate absorbing capacities by way of isothermal absorption in the brown soil. It concluded that the larger the number of functional group (-COOH, -OH) of organic acids was, the greater the effect on decreasing soil phosphate absorbing capacities, and the affected order was as follows: Lemon acid>oralic acid>tarlaric acid>benzolic acid>acetic acid. Secondly, as concentrations of organic acids increased, the soil phosphate absorbing capacities decreased at the same pH value. And Thirdly, the effect of solutions of organic acids or phosphate added to the soil with different orders on the phosphate absorbing capacities was also different. The decreased order was as the following: the first was by adding phosphate solution before organic acids, the second was by adding phosphate solution after abandoning centrifugal soil organic acids solution, and the third was by putting into phosphate solution after the organic acids absorbed.