长期施肥对红壤性水稻土磷素积累与形态分异的影响

Effects of Long-Term Fertilization on the Accumulation And Forms of Phosphorus in Paddy Soil Derived from Red Earth

通过红壤性水稻土19 a肥料长期定位试验，结果表明，不施磷处理的土壤磷素处于耗竭状态，耕层土壤全磷含量持续下降，但耕层以下土层的全磷尚未耗损；连年施磷的土壤耕层全磷含量提高，提高的幅度呈现明显量级关系。在本试验条件下，土壤中各组分无机磷含量以Fe-P和O-P为主体，各占土壤无机磷总量的44.63%和31.27%；其次是Al-P和Ca10-P，分别占11.87%和8.01%，Ca2-P占3.52%；Ca8-P只有当土壤无机磷达到一定丰度和供磷强度时才存在，对水稻磷素营养的贡献无实际意义。各组分无机磷对水稻的有效性以Ca2-P>Al-P>Fe-P>O-P>Ca10-P；而对水稻磷素营养的贡献则以Fe-P>O-P>Al-P>Ca2-P>Ca10-P；长期耗磷或施磷、土壤各组分无机磷减少或增加量的排列顺序与土壤中各组分无机磷相对含量的顺序一致，从而保持红壤性水稻土无机磷组分相对含量的稳定。化学磷肥与有机肥配合施用，可以降低积累态磷转化为O-P和Ca10-P的比率。

：Based on the long-term fertilizer experiment（19 years）in paddy soil derived from red earth, the methods proposed by Jiang & Gu（1989）are adopted to study the effects of long-term fertilization on the accumulation and loss of the soil phosphorus and on the forms of soil inorganic phosphorus in paddy soil. The results show that the soil total P contents take place greater change, under different fertilizer program. In the treatments of no P application, the contents of total P in surface soil continually decrease, and the amount of P lost are accordant with the biological yield of rice, but P is no less in below surface soil, up to now. While the contents of total P increase in the continual P application treatment, and the amount of P accumulated in the treatments of high application rate of P is higher than that in the treatments of low application rate of P. Fe-P and O-P are the main forms in the inorganic P in soil, accounting for 44.63% and 31.27% of total inorganic P, respectively. The next are Al-P（11.87%）and Ca10-P （8.01%）. And Ca2-P is comparatively low. Ca8-P exists only when the content of P and the P supplying intensity are high, so it is not significant for the rice P nutrition. The availability of various forms of inorganic P is Ca2-P>Al-P>Fe-P>O-P>Ca10-P, while the contribution to the rice P nutrition is Fe-P>O-P>Al-P>Ca2-P>Ca10-P. The amount order of various forms of inorganic P lost or accumulated is accordant with that of the relative contents of various forms of inorganic P, keeping the stable of the relative contents of various forms of inorganic P in paddy soil. In the case of combined application of P with manure, the percentage of accumulative P transforming to O-P and Ca10-P is low.