Effect of Nitrogen and Water Management on Panicle Development and Milling Quality of California Rice (Oryza sativa L.)

Nitrogen fertilization and water management are the most important agronomic factors in determining the yield and milling quality of rice. Yet little information is available on the effect of nitrogen and time of drainage on the uniformity of rice grain development on a panicle. The objectives of this study are 1) to evaluate the effect of nitrogen application on the uniformity of grain development on a panicle, and 2) to determine the combined effect of time of drainage and nitrogen application on rice yield and milling quality. Results show that nitrogen has a significant effect on grain filling characteristics. Nitrogen reduces grain filling rate, increases duration of grain filling, increases tiller numbers and decreases grain weight. The time of drainage is critical to the recovery of head rice. Generally speaking, late drainage tends to increase the head rice recovery, and its impact on rice milling quality is increased with an increased rate of nitrogen application.