Abstract:

【Objective】 In order to provide a scientific basis for reusing of straw and organic wastes of straw recycling, an experiment was carried out to study the effects of straw and organic wastes of straw recycling returning on soil fertility, ecologic benefits and economic benefits. 【Method】 Two control treatments with no fertilizers and sole chemical fertilizers and four organic matters treatments (straw, fungus dregs, cattle dung and biogas dregs) were designed to determine the effects of above four organic residues on soil physical and chemical characteristics, CH4 and N2O emission, rice yield, and economic benefits. 【Result】 The results showed that the soil bulk density was decreased and soil porosity and stability of soil aggregate were increased in the four organic waste residues application treatmeats. The content of soil organic matter and available nutrients were also increased in the four organic waste residues application treatments. Therefore, soil fertility was improved after the four organic waste residues applied. Compared with the yield in CK treatment, the yield in treatments with the incorporation of organic waste residues had a decrease in early rice and an increase in late rice, but the differences were not significant. However, the ratio of output and input was significantly increased with organic waste residues application. Organic waste residues incorporation increased CH4 emission and decreased N2O emission significantly. The CH4 emission increased in NPK+S treatment was the most and NPK+FD, NPK+BD were less. With the incorporation of organic residue (6 250-22 500 kg?hm-2), the amount of chemical fertilizer applied was reduced by 10%-20%. Such practice not only conserves the energy but also reduces the environmental pollution potential threat. 【Conclusion】 Considering the production, economic and ecological benefits, it was suggested that the incorporation of fungus dregs and biogas dregs with reduced chemical fertilizer should be adopted in the double crop rice area of south China.

Key words: organic waster, recycle, soil fertility, ecologic benefit, economic benefit