Comparison of sensor-based irrigation scheduling method and Arkansas irrigation scheduler

Authors: Sui, Ruixiu; Vories, Earl

Submitted to: Irrigation Association Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/8/2018
Publication Date: 12/3/2018
Citation: Sui, R., Vories, E.D. 2018. Comparison of sensor-based irrigation scheduling method and Arkansas irrigation scheduler. Irrigation Show & Education Conference, Dec. 3-7, 2018, Long Beach, CA. pp 1-8. 2018. (Proceedings)

Interpretive Summary: Ongoing depletion and stagnant recharging of the Mississippi River Valley Alluvial Aquifer jeopardize the long-term availability of the aquifer and place irrigated agriculture in the Mid-South on an unsustainable path. It is necessary to seek improved irrigation technologies to increase water use efficiency for sustainable use of water resources. USDA ARS Scientists at Crop Production Systems Research Unit in Stoneville, MS and Cropping Systems and Water Quality Research Unit in Portageville, MO conducted researches on comparison of the sensor-based irrigation scheduling method (SBISM) and the Arkansas Irrigation Scheduler (AIS) in Mississippi Delta. Two-years tests in soybean crops showed the number and time of irrigation events scheduled by the SBISM differed from those predicted by the AIS. A couple of mismatching of the irrigation recommendations between these two approaches occurred at the early and late growing season, which might have been caused by the lack of precision in the AIS crop coefficient functions and very high soil moisture content due to large amounts of precipitation in the late growing season. Results of this study provide useful information for improving the AIS prediction accuracy in irrigation management in the Mid-South.

Technical Abstract: Sensor-based irrigation scheduling methods (SBISM) use sensors to measure soil moisture and schedule irrigation events based on the soil-water status. With rapid development of soil moisture sensors, more producers have become interested in SBISM. Arkansas Irrigation Scheduler (AIS) is a weather-based irrigation scheduling tool and has been adopted in the Mid-South for many years. Field studies were conducted for two years in Mississippi Delta to compare the SBISM with the AIS. Soil moisture sensors were installed in multiple locations of a soybean field. Soil water contents of the field were measured across the growth season. Meanwhile, the AIS was installed in a computer. A weather station near the soybean field was employed to obtain all data required by the AIS. Number and time of the irrigation events triggered by the SBISM were compared with those scheduled by the AIS. Results showed the number and time of irrigation events scheduled using the SBISM were often different from those predicted by the AIS, especially during the 2018 growing season. Both the sensor-based irrigation scheduling method and the AIS could be used as tools for irrigation management in the Mid-South region, but extra attention to the effective portion of rainfall or irrigation would be needed in some years.