Increasing yield and nitrogen use efficiency of rice through multiple-split fertilizer application

The low availability of nitrogen (N) is one of the most important limiting factors impeding the increase in rice yield among the various factors. Split N fertilizer applications can play an important role in nutrient management strategy that is productive, profitable and environmentally responsible. In this study, the recoveries and efficiencies of a multiple-split N fertilizer application of were determined using 15N labeled fertilizer, in order to provide science-based foundation for the nitrogen management in sustainable rice production. A lysimeter experiment with five treatments in four replications was set-up T0 (control). T1 (45 kg N ha"- "1), T2 (90 kg N ha"- "1), T3 (135 kg N ha"- "1) and T4 (180 kg N ha"- "1). 15N tracer analysis showed that, on average, only 30% of applied N is recovered by the crop following one time basal application. In contrast, higher fertilizer nitrogen use efficiencies (FNUE) (>50%) were observed following multiple-split N application. The result of FNUE also corroborates with the significant increase in rice grain yield. Many crops, however, have different nutrient requirements, therefore as in all fertilization strategies, it is highly recommended that source, rate, time and place of application should be considered in making split fertilization decisions. (author)