Research On How Soil Phosphorous Pool Changes In Long Term Fertilization And Its Impact On Rice Yielding And Quality

Phosphorous is not only the macroelement for crop growing, but also the cause of eutrophication, which has been placed as the priority of nutrient recycling in farmland ecosystem. Based on the experiment of long-term-fertiliztion in Suzhou Agricultural Sciences Institute, This article aimed to establish a qualitative or quantitative relationship between soil P and rice physio-ecology, by analyzing the differences of soil P pool and its action on the growing trait of rice.1. Whether or how to apply P fertilizer has an appreciable impact on soil P pool. Treatments with a long term P fertilizer, have their soil P pool notably more abundant than those without, with each part of inorganic P higher. Especially, they can provide more available P, including Ca2-P and Al-P. Treatments of CPK、CNPK、CNP have respectively33.94、19.15、19.67times of Ca2-P as much as Check (CO), and28.85、21.64、17.63times of Al-P, while there were no oblivious difference among treatments without P fertilizer. Slowly available Fe-P and Ca8-P are also higher in soil with P fertilizer, especially for the treatment of CPK, as well as potential Ca10-P and Oc-P. But the percentage of potential P in inorganic P has declined. Content of total P in soil has reduced even in treatments with P fertilizer, which reduced little. Treatments without P fertilizer had their total P less than50%of30years ago, and available P dropped to less than25%.2. P fertilizer can bring forward the heading stage of rice, and enrich chlorophyll of leaf blade, and increase the ratio of tillering. CNPK increased its production42.25% than CNK, and CNP15.13%more than CN. Otherwise P can increase the ratio of unpolished rice, and induce the ratio of polished rice. It also decreased chalky kernel percentage, increased chalky area, while decreased protein content and increased amylase.3. Rice starch accumulated quickly at first and slowed down in the later period, staying in a relatively stable state. At the beginning of grain grouting, there was a linear correlation between panicle P and starch. In the middle of grouting, Ca2-P also correlated linearly with panicle sugar.