长期定位施肥对棕壤无机磷形态及其有效性的影响：Ⅱ肥料中的磷向各形态无机磷的转化及其有效性

研究了棕壤中磷肥和有机肥带入的磷向土壤各形态无机磷的转化情况及其有效性。结果表明：在棕壤中存在着钙磷体系的有效性转化，Ca10-P在棕壤中难以积累；施肥增加的土壤无机磷的增量以形成Fe-P和Al-P为主，约占60％－78％；而形成Ca8-P和Ca2-P的比率则是有机肥的转化率明显高于磷肥；在棕壤中，Fe-P是作物吸收的重要磷源，Ca8-P的作用介于Fe-P和Al-P之间，Ca2-P虽也是棕壤中速效磷源，但对作物吸磷贡献不大。

Effects of Long-termFertilization Experiment on the Inorganic Phosphorus Forms in Brown Soil and ItsAvailability

The form transformation of inorganic-P added by fertilization and its availability were studied in this paper. It showed that it was difficult for Ca10-P to accumulate in Brown Soil owing to the shift of Ca10- P availability. The increment in soil inorganic-P mainly shifted to Fe-P and Al- P which totally shared 60-78 percent. However, the increment ratio of Ca8 - P and Ca2 - P were evidently different between phosphate fertilizer and oiganie fertilizer and the organic fertilizer showed a larger proportion. Fe-P was a important form of inorganic-P to crops, and the role of Ca8-P was among Fe-P and Al-P. however Ca2-P contributed little to crop uptake.