室内干湿培养对磷肥在热带土壤中的转化和有效性的影响

Effects of the Indoor Dry-wet Incubation on Transformation and Availability of Phosphate Fertilizers in Tropical Soils

对海南岛6种类型土壤不同施磷量的室内干湿培养和应用土壤无机磷分级方法，研究水溶性磷肥在热带上壤中的转化和有效性。结果表明：施磷处理经室内干湿培养8a，磷在土壤中的转化速率低于盆栽作物条件，特别是土壤O－p在培养前后变化很微。其中土壤有效P以年均4．5％的幅度下降，Al－p和Fe－p分别以年均2．1％和1．7％的幅度下降，而Ca－p和O－p则分别以年均1．2％和0．2％的幅度增长。土壤有效磷的变化趋势与Al－p、Fe－p相一致，而与Ca－p和O－p相反，说明磷肥在土壤中转化形成的Al－p和Fe－p为活性态P，是热带上镶有效磷的主要形态。

Transformation and availability of water so1uble phosphate fertilizers in tropical soils have been investigated by indoor dry-wet incubation and soil inorganic phosphorous classification on six types of soil supplied with different quantities of phosphate fertilizers. The resu1ts showed that the treatments of phosphate fertilizer application under 8years dry-wet incubation had lower rates of P inversion in the soils than those under pot -raised crops,especial1y,the change of O -p in the soils,which was very tiny from the beginning to the end of the incubation. The available P decreased at an average rate of 1- 5% per year,and the Al-p and Fe -p were reduced at respective average rates of 2. 1% and 1. 7% per year,whereas the Ca-p and O-p increased by 1. 2% and 0. 2%per year respectively. The change of the available-p in the soils is consistent with those of Al-p and Fe-p,but contrary to those of Ca-p and O-p. This demonstrated that the Al-p and Fe-p transformed from phosphate fertilizers in the soils were in the form of active P and the main forms of the available -p in the tropical soils.