Effects of late nitrogen fertilizer application on head rice yield, protein content, and grain quality of rice

Rice yields of 10 and 6 t/ha can be achieved in the humid tropics during the dry and wet seasons, respectively, At these high yield levels, late nitrogen (N) fertilizer application at flowering at lire International Rice Research Institute (IRRI) farm often results Tn increased rough rice yield of IR cultivars and is accompanied by higher milled rice protein and increased total and head-milled rice contents. The combined effects of N application al flowering resulted in a 30-60% increase in head-rice protein yield in three field experiments. In general, milled rice translucency improved, but Kett whiteness decreased with late N fertilizer application. Brown-rice weight was not affected by late N application. In most cases, there was a significant positive correlation between head rice content, milled rice protein, and translucency. Thus, when crop management seeks to achieve yields that approach yield potential levels, late N fertilizer application provides an option to improve milling and nutritional quality of rice grain.