Comparison Between Organic and Conventional Rice Productions in Soil Nutrient Balance

Rice production in Wanzai County of Jiangxi Province was selected as a case for study. Questionnaires were issued to and collected from organic and conventional farmers on agricultural production for comparison and analysis of soil building methods and nutrient input, output and balance of the rice-soil system relative to farming mode. Results show that the proportion of organic farmers who build their soils by applying organic manure and growing green manure crops is significantly higher (P＜0.01) than that of the conventional farmers, and the proportion of organic farmers who adopt interplanting and straw incorporation are is also significantly higher (P＜0.05)than that of the conventional farmers.In terms of nutrient management, both organic and conventional rice production systems had nitrogen surplus, which reached 57.8 kg/hm2 and 36.3kg•hm² , respectively, or 21.7% and 7.6%, respectively, in surplus rate. The two also had phosphorus surplus, too, which reached 35.4 kg•hm² and 64.7 kg•hm², respectively, or 147.5% and 217.9%, respectively, in surplus rate, much higher than the permissible surplus and deficit rates in P budgeting. Compared to conventional farmers, organic farmers are ready to build up their soil by adopting ecological farming practices, but which may alsowould lead to higher N and P surpluses, thus posing certain environmental risk .