Effects of Water Management Strategies on Total Water Use, Yield, Weed Control and Economic Return in U.S. Rice Production.

Rice growing regions of the Mississippi, Arkansas and Louisiana deltas are experiencing steady decline in the Mississippi Alluvial Aquifer. Depletion of this natural resource combined with regulations for well use make it imperative in finding sustainable alternative methods for U.S. rice production. The objective of this study was to investigate the effects of various water management strategies as they relate to total water use, yield, weed control, and economic return in rice production. Three rice cultivars (Rex, CL151, XL753) were produced on a Sharkey (very fine, smectitic, thermic, Chromic Epiaquerts) clay soil located in Stoneville, MS. Three water management strategies (continuous flood, alternate wetting and drying, furrow irrigated) were investigated. Irrigation timings were managed at different soil water levels (4”,8”,12”,16”) using PVC pipes placed within the soil profile. Total water use for each treatment was determined using McCrometer flow meters. Five fertilization treatments totaling 168 kg N ha-1 were applied at different split intervals (100, 75/25, 50/50, 50/25/25, 25/25/25/25) according to growth stage. Biomass was harvested from 0.9m of row and analyzed for % N content. Conventional and Clearfield herbicides were applied at different growth stages and evaluated for weed control. Rice grain yield was determined at harvest maturity. The effects of three water management strategies on total water use, rice yield, weed control and economic return will be discussed at length.