Rough Rice and Milling Yields as Affected by Nitrogen, Harvest Moisture, and Cultivar

Abstract

Improvements in rice (Oryza sativa L.) production in the mid‐south United States have been made through advances in N management, harvest strategies, and cultivar selection. Efficient fertilizer‐N management is important for producing large yields. Harvest moisture content (HMC) affects grain quality [i.e., milled rice yield (MRY) and head rice yield (HRY)], as harvesting above or below optimum HMC results in decreased milling yields. Research was conducted from 2011 to 2013 investigating rough rice and milling yields as affected by fertilizer‐N application (0, 45, 90, 135, and 180 kg N ha−1), HMC (high, medium, and low), and cultivar (‘Cheniere’, ‘CLXL745’, and ‘Wells’). Maximum rough rice yields of 8916, 10,263, and 9353 kg ha−1 were calculated at N rates of 135, 149, and 146 kg N ha−1 for Cheniere, CLXL745, and Wells, respectively. At N rates to achieve maximum rough rice yield, MRY and HRY were 98 to 99.9% of the maximum milling yield within a cultivar‐HMC combination, excluding Wells harvested at low HMC. Within a cultivar–HMC combination, HRYs were <1 to 25% points greater at the maximum HRY–producing N rate than the minimum. Nitrogen rates needed to maximize rough rice yield and harvesting at high and medium HMC lead to near‐maximum HRYs; however, harvest at low N rates and HMC reduced HRY, particularly for CLXL745 and Wells. Further research focused on other hybrid and pure‐line rice cultivars will ensure that the current data are consistent for a wide range of cultivars.