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United States Department of Agriculture

Agricultural Research Service

Research Project: OPTIMIZING IRRIGATION MANAGEMENT FOR HUMID CLIMATES

Location: Cropping Systems and Water Quality Research

Title: PERFORMANCE OF A VARIABLE RATE CENTER PIVOT SYSTEM

Authors
item Vories, Earl
item Tacker, Phil - UNIV OF ARKANSAS
item Stephenson, Daniel - UNIV OF ARKANSAS
item Bajwa, Sreekala - UNIV OF ARKANSAS
item Perry, Calvin - UNIV OF GEORGIA

Submitted to: Proceedings of the World Environmental and Water Resources Congress Conference
Publication Type: Proceedings
Publication Acceptance Date: January 29, 2008
Publication Date: May 12, 2008
Citation: Vories, E., P. Tacker, D. Stephenson, S. Bajwa, and C. Perry. 2008. Performance of a variable rate center pivot system. Proc. World Water and Env. Resources Congress. ASCE. (unpaginated CDROM).

Interpretive Summary: US farmers are adopting a precision agriculture approach to many parts of their farming operations, but some of the potential benefits may not be realized if they don't change the way they apply irrigation water. A system for variable-rate (VR) water application was installed on a center pivot irrigation system at the Judd Hill Plantation in northeast Arkansas and the objective of this research is to monitor the system for possible water and energy savings. Although water use was reduced by turning off the large sprinkler on the end of the system, fuel use was not reduced. Future studies are planned to monitor the system as more of the sprinklers are turned off and test for fuel savings. Water and fuel savings will benefit farmers through reduced production costs and everyone else will benefit from protecting aquifers and reducing oil demands.

Technical Abstract: US farmers have access to equipment for variable-rate application of most inputs, but some potential benefits of precision agriculture may be masked by uniform application of irrigation water. A system developed at the University of Georgia for variable-rate (VR) water application was installed on a 400-m long center pivot system at the Judd Hill Plantation in northeast Arkansas. The objective of this research is to monitor the system to determine the potential for water and energy savings. A replicated large-plot study was initiated in 2006 based on soil mapping units. Application rates were 13, 19, and 23 mm. No significant cotton yield differences were observed in 2006, probably due to rainfall at the site in July and August. Instrumentation installed in 2007 showed a slightly lower water flow rate and increased water pressure when the end gun was shut off, but the fuel flow rate did not change. The water flow rate decreased during the study period and an additional sensor will be added to test for changes in the water table depth. Future studies are planned to repeat the large-plot study of 2006, monitor the system under a wider range of operating conditions, and investigate possible variable rate nitrogen application through the irrigation system.

Last Modified: 8/1/2014
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