Evaluation of Variable Rate Irrigation in Humid Region

摘要

Variable rate irrigation (VPJ) is a new irrigation method in irrigation industry. VRI technologies allow producers to site-specifically apply irrigation water at variable rates within a field to adjust the temporal and spatial variability in soil andplant characteristics. Adoption of VRI has the potential to improve water use efficiency. VRI method was evaluated in soybean and corn in Mississippi Delta. Soil apparent electrical conductivity (EC) was used to delineate VRI management zones and createVRI prescription maps. Irrigation was scheduled using soil moisture content measured by soil moisture sensors. Crop yields and irrigation water productivity in VRI treatment was compared to that in the uniform rate irrigation (URI) treatment. Results demonstrated that the VRI saved 25% irrigation water in soybean and 21% in corn. Irrigation water productivity (WP) of VRI in soybean was 31% higher than the URI. WP of the VRI in corn was 27% higher than the URI. VRI management was superior to the URI in terms of irrigation water use efficiency. Soil EC coupled with soil physical properties could be used to establish irrigation management zones for VRI practice.