The Effect of Various Water Management Strategies on Rice Yield, NUE, and Soil Chemical Properties on a Sharkey Clay Soil.

Water management strategies in rice production can influence grain and milling yield, nitrogen use efficiency (NUE) of the plant, soil chemical properties, and input costs such as pesticide use and water quantity. Multiple water treatments were evaluated for six popular southern US varieties and conducted on Sharkey clay (Chromic Epiaquerts). Treatments were randomized complete block within each irrigation scheme. The four irrigation schemes were: Continuous flooding in the drill-seeded, delayed flood cultural system; flush irrigated(flush weekly, but make sure aerobic conditions persist); Intermittent flood irrigation; and typical irrigation practices for straighthead reduction. Grain yield was measured from each of the six entries grown under the different water management regimes. Inputs were recorded for water usage, fertilizer, and pesticides(i.e., herbicides, fungicides, insecticides) for each water management scheme to determine a cost of production for these selected inputs. pH, Oxidation/Reduction Potential(ORP), temperature, rain, and humidity data was collected throughout the study. Greenhouse gas samples were taken every week throughout the growing season and were analyzed by LSU. Water input was decreased by 25% in the intermittent scheme when compared to continuous flood while maintaining the same yield. The flush irrigated treatment saw a dramatic yield loss, as well as shorter plant height, less biomass, and less NUE for all varieties within the treatment. Our data suggest that water management directly effects rice grain yeild, physiological properties, soil chemical properties, and production inputs such as water use and pesticide costs.