长期施肥对红壤性水稻土磷素积累与形态分异的影响

通过红壤性水稻土19a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A1-P和Ca

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

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 A1-P (11.87%) and Ca10-P (8.01L%). And Ca2-P is comparatively Iow. Caa-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＞A1-P＞Fe-P＞O-P＞Ca10-P, while the contribution to the rice P nutrition is Fe-P＞O-P＞A1-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.