Effects of Different Treatments of Fertilization and Irrigation on the N-utilization Rate and Water Productivity of Rice

[Objective] The aim was to provide scientific basis for reasonable N-fertilizer application and irrigation in paddy field. [Method] The change law of N-utilization rate and water productivity of rice was studied through fertilization and irrigation experiments. [Result] The determination results of difference method indicated that the N-utilization rates of the 2 N-fertilization levels had no significant difference; under the same irrigation model,the N-utilization rates of water-saving irrigation were higher than that of flooding irrigation in the N-fertilization treatments of 30%base fertilizer + 30%tillering fertilizer + 30%jointing fertilizer + 10%heading fertilizer and 50%base fertilizer + 50%jointing fertilizer. The determination results of isotope dilution method indicated that the N-utilization rate of water saving irrigation was higher than that of flooding irrigation. The irrigation amounts of whole growth period of different fertilization treatments had no significant difference,but that of different irrigation models had significant difference. The water productivity of rice was increased along with the increase of fertilization amount. The results of variance analysis indicated that the water productivities of rice under different fertilization models had no significant difference,but that under different irrigation models had extremely significant difference. [Conclusion] Both reasonable fertilization and water-saving irrigation could enhance the N-utilization rate and water productivity of rice significantly.