| To study different the way of using straw and soil management modes, soil's physical and chemical properties, microbial quantities ,enzyme activities , fertilization, yield and relations among them are studied, whose results show:1. In surface soil among different treatment, the content of total N.P.K,available N. P.K and organic are highest under MG (no-tillage high standing-stubbles) treatment, followed by M(clean no-tillage) and then by FZ(mowing and burying straw), and it is lowest under F (clean tillage) treatment. The peak of soil total N and available N appear in neating stage. There have the same trend of fluctuation of total P and available P in rice vigrous growth stage , the content of which is low in booting stage and mature stage. The content of total P.K, available P.K under no-tillage conditon is higher than the content of which under tillage, there is no notable differences under no-tillage treatment. Soil organs matter were improved by straw back to soil. The content of total N.P.K,available N.P.K and organic are the highest under FZ treatment in deep soil, there is no significantly different and law between MG and M.2. Traw returning increased the quantity of soil bacteria,fungi and actinomycetes, and bacteria> actinomycetes >fungi. In surface soil, soil bacteria,fungi and actino -mycete had the same trend of change, MG>M>FZ>F, fiber decomposition rate have the trend of change, MG>FZ>M>F. The quantity of bacteria is lower in other stage than that of the former test except in booting stage, the quantity of fungi is always lower than former test, actinomycete has lower the number than former test except booting and maturing stage. Gether with the soil layer's deepening, the quantities of the three major microbes are reducing,appearing a tendency of deeper soil layer, lower quantity of microbe. The number of microbes of FZ treatment is the most in deep soil. |
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