Variable Rate Irrigation

Problem & Solution
Most center pivot irrigation systems currently in use apply a constant rate of water, yet very few fields are uniform.  A field's inherently variable nature stems from factors such as soil type, topography, multiple crops, drainage ditches and waterways, and other non-cropped areas.  To complicate matters, most fields are irregularly shaped and some even have structures that may be in the pivot path, such as a house or barn. Thus, to optimize crop production and increase water use efficiency, a method is needed for delivering irrigation water in optimal, precise amounts over an entire field.  To provide just such a possible solution, in 1999, the University of Georgia Tifton Campus teamed up with FarmScan from Perth Australia and Holder Ag Consulting in Georgia to develop and commercialize Variable Rate Irrigation or VRI.

What is Variable Rate Irrigation (VRI)?
Variable-rate irrigation is an innovative technology that enables a center pivot irrigation system to optimize irrigation application.   Most fields are not uniform due to natural variations in soil type or topography.  Some farmers manage these individual zones by either not utilizing the more problem areas or by planting multiple crops.  VRI technology allows farmers to easily apply varying rates of irrigation water based on the individual management zones within a field.

How does VRI work?

Our VRI system retrofits onto existing center pivot systems and works by integrating GPS positioning into a control system which cycles individual sprinklers or groups of sprinklers ON and OFF (seconds ON per minute) and varies travel speed to achieve desired rate within management zones.

What are the benefits of VRI?
With VRI farmers can have an increase in crop yield and quality.  The technology can eliminate watering non-crop areas and irrigation-induced runoff thus saving water.  And it can improve the quality of rainfall-induced runoff therefore decreasing stream sediment pollution.

Does my pivot need VRI?
Your center pivot system could benefit from VRI if your field has:

  1.  Overlap areas
  2.  Non-crop areas
  3.  Boggy or extra dry areas
  4.  Varying soil types

As of spring 2008, Farmscan has done 47 VRI installations in the US.

Where can I find out more about VRI?
Advanced Ag Systems Inc

Project Leader: Calvin Perry
Contact Info:
Affiliation: University of Georgia
8207 GA Hwy 37
Camilla, GA 31730
(229) 522-3623

Andrea Milton
Contact Info:
Affiliation: University of Georgia
P.O. Box 748
Tifton, GA 31793
(229) 386-3377

Rick Heard
Contact Info:
Affiliation: Advanced Ag Systems Inc
(913) 660-2954