Effect of Different Fertilization Methods on Nitrogen Utilization and Balance under Rice-Wheat Rotation System

In this paper,the effects of different three treatments of CK,traditional fertilization(TF) and optimum fertilization(OF) on the system productivity,nitrogen utilization and balance under rice-wheat rotation system in Chengdu plain of Sichuan were studied in field trials.The results showed that optimal fertilization could improve yield of wheat and rice and system productivity significantly which were 15.04 %,20.35 % and 18.37 % more than that of TF,respectively.Optimal fertilization could promote the absorption and utilization of nitrogen for crop grain and the increase efficiency of fertilization use.Under the optimal fertilization condition,the nitrogen use efficiency of wheat was 28.19 %,while that of rice was 48.89 %,which was 11.29 % and 9.06 % more than that of TF.Under the condition of rice-wheat rotation,the soil nitrogen surplus of TF and OF was 82.89 and 95.34 kg/hm2,while the soil nitrogen deficit of no fertilization treatment was-89.04 kg/hm2.Nitrogen loss was the main form of the fate of nitrogen fertilizer in soil-plant system and optimal fertilization could decrease nitrogen loss significantly in wheat season.