|Stone, Kenneth - Ken|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/4/2013
Publication Date: 11/4/2013
Citation: Stone, K.C., Bauer, P.J., Millen, J.A. 2013. Evaluation of potential water conservation using site-specific irrigation. In: Proceedings of the 2013 Irrigation Show and Education Confernece, November 4-8, 2013, Austin, Texas. 2013 CDROM.
Technical Abstract: With the advent of site-specific variable-rate irrigation (VRI) systems, irrigation can be spatially managed within sub-field-sized zones. Spatial irrigation management can optimize spatial water use efficiency and may conserve water. Spatial VRI systems are currently being managed by consultants who use either the farmer’s familiarity with the field or some other measure of field variability, such as soil maps or soil electrical conductivity. The goal of the research is to provide farmers and consultants a tool to evaluate the potential benefits of implementing VRI. The specific objective of this research is to evaluate the potential water savings using VRI management compared to uniform irrigation management. The 20-year simulation study was carried out on selected fields with varying degrees of soil and topographic variability. The simulated field had 12 soil mapping units with a 65% difference in soil water holding capacity. The 20-year simulation covering all weather conditions for each soil produced only 2 significantly different irrigation management zones. However, when the 20-year period was divided into periods with different ratios of evapotranspiration to rainfall, the simulations identified 5 to 6 management zoned with significantly different irrigation requirements. These results indicate that variable rate irrigation system systems design and management should not be based on long term average weather conditions. Using years with differing weather conditions should be used for potentially identifying management zones for VRI systems. Compared to uniform irrigation management, managing irrigation using multiple management zones saved between 21 and 42 mm of irrigation for specific zones.