Olsen P评估植物有效磷的有效性和土壤P吸附参数及它们间的关系

Assessing the feasibility of Olsen P and P sorption parameters in acidic soil and their relationship

为了查明Olsen法(碳酸氢钠提取态磷)是否适用于酸性土壤有效磷的测定,土壤P吸附参数及它们之间的关系,利用同质地不同磷含量酸性土壤提供了这方面的信息。结果表明,Olsen法适用于酸性土壤植物有效磷的测定,Olsen P与植物磷吸收量表现出极显著相关。磷最大吸附量(Qm)与磷吸附强度(K)显著负相关。土壤缓冲容量随取样次数增加逐步减少,第3次取样时,土壤缓冲容量高磷处理(P3)>中磷处理(P2)>低磷处理(P1)>无磷处理(P0),说明随着生长时间增加,作物从土壤带走磷量增加,含磷量低的土壤磷缓冲容量随之降低。Olsen P与Qm,K均无显著相关,但土壤磷吸附饱和度、Olsen P均证实,实验用土壤目前不会因增加施磷量而引发环境问题。磷吸附参数与Olsen P从环境和农业生产需求两方面说明了土壤磷素丰缺状况。

The aim of this study was to assess the feasibility of bicarbonate-extractable P （Olsen P） on detecting plant available P in acid soil and analyze phosphorus （P） sorption characteristics in soil and their relationships with Olsen P. Results showed that plant available P could be estimated by Olsen P in this acid soil and an extremely sig- nificant correlation between Olsen P and plant available P was observed. Phosphorous sorption was characterized by Langmuir equation summarized by three sorption parameters： P sorption maximum （Qm）, P sorption strength （K）, and P saturation degree. P adsorption maximum （Qm） had a significant negative correlation with P sorption strength （K）. The soil P buffer capacity decreased over time. At the third soil sampling time, P buffer capacity was the highest with the highest P rate （P3） followed by the second P rate （P2）, the lowest P rate （P1）, and P0 （no P adding） in the 75th day sampling soils. This suggested that adsorption of P by crops may decrease soil buffer capacity due to a lower P content than other soils. Qm and K were not significantly correlated to Olsen P. However, P saturation degree and Olsen P confirmed that an increase of P application could not cause environmental issues. P status in soil can be characterized by P adsorption parameters and Olsen P.