Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/2/2005
Publication Date: 12/20/2006
Citation: Smith, M.C., Massey, J.H., Johnson, A., Thomas, J., Tacker, P.L., Vories, E.D., Lancaster, S., Andrews, A., Ampim, P. 2006. Multiple-inlet plus intermittent rice irrigation reduces water use while maintaining acceptable yields. Proceedings 31st Rice Technical Working Group, p. 135. (CD-ROM)
Technical Abstract: Research was conducted in 2004 and 2005 to determine the potential for water savings using multiple-inlet irrigation plus intermittent flooding compared to continuously flooded rice. Experiments were conducted at five farms ranging from the southern-most Mississippi Delta to the northeast corner of Arkansas. The control field at each location was continuously flooded using the grower’s traditional practices. The experimental field used multiple-inlet irrigation plus intermittent flooding, whereby the flood was established at the appropriate time using 15-in diameter disposable plastic pipe to deliver water to each paddy simultaneously. After two weeks of continuous flooding, the experimental field was allowed to dry until about half of each paddy had exposed soil. At this point, the field was reflooded to an average depth of 3 to 4 in. This cycle was repeated on a 5- to 9-day interval throughout the growing season. Rain gauges and flow-meters recorded all water inputs. Water-depth loggers recorded flood depth every 10 min in at least 4 paddies within each field. Flagleaf samples were collected at the booting stage and analyzed for nutrient content. Weed, insect, and disease control was excellent at all locations and unaffected by water management. Flagleaf samples averaged 3.1 and 3.7% nitrogen in 2004 and 2005, respectively, and were not affected by water management. Averaged over locations and years, rice yielded 165 bu/A and was unaffected by water management. Intermittently flooded rice used 24 in water compared to 32 in with continuously flooded rice. A rice irrigation model was developed using the water depth logger data. The model was run using twenty-five-year historical daily rainfall measurement from 4 Mississippi locations and 5 Arkansas locations. The model predicted intermittently flooded rice to consume 22 in irrigation and continuously flooded rice to consume 34 in irrigation.