Effect of long-term located organic-inorganic fertilizer application on rice yield and soil fertility in red soil area of China.

【Objective】The effects of organic manure application on rice yield and soil fertility in double-rice cropping region in south China were evaluated synthetically.【Method】Successive 25-year field experiments were conducted in south Jiangxi of China.Five different treatments with mixed chemical and organic fertilizers,no fertilization(CK),N,P and K chemical fertilizers only(NPK),70% chemical fertilizers and 30% organic manure(70F+30M),50% chemical fertilizers and 50% organic manure(50F+50M),and 30% chemical fertilizers and 70% organic manure(30F+70M) with their replications were examined.Each N,P and K application rate was the same in all the treatments(except no fertilization in CK).Crop-rice yield and soil fertility in each treatment were measured for comparison.【Result】During the twenty-five years plantation,organic manure application combined with chemical fertilizers treatments were 65.4%-71.5%(P0.05) higher than CK,and 3.9%-7.8%(P0.05) higher than NPK treatment in yield.Rice yield of 30F+70M treatment was the highest in all treatments,reached 12 346.90 kg·hm-2.The difference between 30F+70M and NPK treatments in yield was widening with each passing year,the same as the 30F+70M and 70F+30M treatments.No fertilization for a long time result in soil fertility degeneration,there was a significant increase of soil fertility with a long-time balanced fertilization,and organic manure application combined with chemical fertilizers showed the most obvious increase of soil fertility relatively.【Conclusion】In red soil area,the function and stability of organic manure application combined with chemical fertilizers on rice yield was the best among all treatments in this study.The rice yield and soil fertility could be improved under the condition of high-quantity level of the organic fertilizer with chemical fertilizers.