Nitrogen Uptake and Growth of Irrigated Rice as Affected by Nitrogen Rates

Abstract

Rice fertilized with 50, 100 and 150 kg of N/ha produced 5.0, 6.9 and 7.8 t/ha, respectively, of dry rough rice. Maximum uptake of N was 90, 124, and 148 kg/ha at the respective rates. At the rate of 100 kg of N/ha, uptake of N by the entire rice plant, including roots, was about 20 kg/ha during the first 4 weeks, 60 kg/ha during the following 2 weeks, and 40 kg/ha during the remainder of the cropping period. The N levels had no residual effects on a subsequent rice crop. About 66% of the first 50 kg/ha increment of N applied and 50% of the second increment were recovered in the rice plants in this experiment conducted in lysimeter tanks, with no losses by leaching.