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采用土柱模拟试验,研究了柠檬酸、草酸和乙酸在持续淋溶条件下土壤磷的动态释放特征及淋溶前后无机磷组分的变化情况。结果表明:相同浓度条件下三种有机酸对供试土壤磷的活化能力大小顺序为:柠檬酸>乙酸>草酸,且不同有机酸淋溶过程中磷的释放特征各不相同。乙酸的最大释磷量及释磷率虽不及其它有机酸处理,但表现出了较好的持续活化能力。持续淋溶条件下,三种有机酸均能显著地活化土壤无机磷,其中柠檬酸和乙酸处理对无机磷的活化效果较好,草酸相对较弱,且有机酸的淋溶使土壤磷素形态构成发生变化;柠檬酸和乙酸作用下各形态无机磷变化率大小顺序为:Ca-P>Fe-P>Al-P>O-P;草酸处理下变化率顺序为:Ca-P>Al-P>O-P>Fe-P,说明三种有机酸对Ca-P的活化最为明显,其次为Fe-P或Al-P,而O-P在淋溶前后变化很小。
Soil column simulation was used to study the dynamic characteristics of soil phosphorus release and the changes of inorganic phosphorus fractions before and after leaching with citric acid, oxalic acid and acetic acid under continuous leaching conditions. The results showed that the order of activation of three kinds of organic acids under the same concentration of soil organic acids was: citric acid> acetic acid> oxalic acid, and the phosphorus release characteristics of different organic acids leaching were different. Although the maximum amount of phosphorus released and the rate of phosphorus release of acetic acid is not as good as that of other organic acids, it shows a good sustained activation ability. Under the condition of continuous leaching, all three kinds of organic acids could significantly activate inorganic phosphorus in soil, of which citric acid and acetic acid activated inorganic phosphorus better, oxalic acid was relatively weaker, and the leaching of organic acid made soil phosphorus form The order of change of inorganic phosphorus under the action of citric acid and acetic acid was Ca-P> Fe-P> Al-P> OP. The order of change was Ca-P> Al-P> OP> Fe-P, indicating that three kinds of organic acids have the most obvious Ca-P activation, followed by Fe-P or Al-P, while OP changes little before and after leaching.