Nitrogen Rates in Single and Split Applications and Yield of Flooded Rice

Abstract

Yields of rough rice increased from 3,830 to 7,950 kg/ha when N rates were increased from 0 to 224 kg/ha in one application. Rice yields increased from 3,830 to 8,210 kg/ha when N rates were increased from 0 to 112 kg/ha, used in two applications. Yields were not increased further by heavier applications of N. The N rates from the single applications did not affect yields of a subsequently planted rice crop that received no N fertilizer. The split applications, however, did increase yields of the following crop. In another experiment, applications of more than 112 kg of N/ha sharply increased damage by blast, when the fungus was not controlled by spraying, and limited yield response to N applications.