Effects of Chemical Fertilizer and Organic Manure on Rice Yield and Soil Fertility

【Objective】 The objective of this study was to probe the effects of chemical and organic fertilizers on rice yield, soil organic matter and soil nutrients. 【Method】 Field investigation and soil sample analysis methods were adopted on a long-term experiment in Qiyang, Station, Hunan province, China. 【Result】 The combined use of chemical and organic fertilizers was an optimum way for high yield and improvement of soil fertility. Application of both chemical and organic fertilizers significantly increased soil organic matter, and application of organic fertilizers increased soil organic matter by 48% compared with the chemical fertilizer. Organic fertilizers made a great contribution to improvement of soil total nitrogen and hydrolysable nitrogen than chemical fertilizer N, but less contribution to soil total P and available P than that of chemical fertilizer phosphorus. The organic fertilizer increased soil total N by 30% and hydrolysable N by 16% while the chemical P fertilizer increased 30% more total P and 115% more available P than did the organic fertilizer. 【Conclusion】 Combined use of chemical fertilizer and manure is important for high yield of rice and improvement of soil fertility.