Evaluation of a descision support system for variable rate irrigration in humid region

Authors: Sui, Ruixiu; Oshaughnessy, Susan; Evett, Steven - Steve; ANDRADE, M - Former ARS Employee; Baggard, Jonnie

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/6/2020
Publication Date: 10/14/2020
Citation: Sui, R., Oshaughnessy, S.A., Evett, S.R., Andrade, M.A., Baggard, J.L. 2020. Evaluation of a descision support system for variable rate irrigration in humid region. Transactions of the ASABE. 63(5):1207-1215. https://doi.org/10.13031/trans.13904.
DOI: https://doi.org/10.13031/trans.13904

Interpretive Summary: Soil properties and plant characteristics can vary considerably within a single field resulting in variability of water need for plant to reach its yield potential. Variable rate irrigation (VRI) technology can site-specifically apply irrigation water at variable rates within a single field to account for the temporal and spatial variability in soil and plant characteristics. Researches on development of new tools for VRI management and evaluation of the impact of VRI management on water productivity are needed. USDA ARS Scientists at Sustainable Water Management Research Unit at Stoneville, MS collaborated with USDA ARS Scientists at Bushland, TX conducted a field study for two years testing a new decision support system (DSS) for VRI in the Mississippi Delta. Test results indicated use of this DSS reduced irrigation water use and increased irrigation water productivity. There is great potential for this system being used for VRI in humid regions.

Technical Abstract: Use of variable rate irrigation (VRI) technology has the potential to improve irrigation water use efficiency (IWUE). VRI hardware is commercially available and could possibly be implemented in any center pivot irrigation system. However, practical methods and algorithms for creating VRI prescriptions have become the bottleneck in accelerating the adoption of VRI. An Irrigation Scheduling Supervisory Control and Data Acquisition (ISSCADA) system for VRI was evaluated for two years in a humid region in the Mississippi Delta. The ISSCADA system was used to manage irrigation in soybeans for two seasons. In field practice, the ISSCADA scanned the field for canopy temperature and remotely collected soil water data from time domain reflectometers and weather data from a nearby weather station. The ISSCADA system automatically generated VRI prescription maps. The maps were modified to include plots managed using soil electrical conductivity (EC)-based VRI prescriptions. Test results indicated there was no difference in crop yield between EC-based VRI and ISSCADA-based VRI management. However, ISSCADA-based VRI management reduced irrigation water use and increased irrigation water productivity in comparison with the EC-based VRI. There is great potential for the ISSCADA being used for VRI in humid regions.