Precision Irrigation Guide for Center Pivots Elisa Flint, Matt Yost, Troy Peters, Clara Anderson, Burdette Barker, and Neil Hansen
Highlights •
•
• •
Variable rate irrigation (VRI) can improve water use efficiency and produce water savings in some conditions. Speed and zone control VRI systems are available to fit different budgets and the variability within the field. Options for creating prescription maps are addressed. Advantages and disadvantages of VRI are discussed.
Introduction Precision irrigation is a process involving technology and specialized equipment to improve the efficiency and effectiveness of agriculture irrigation management. This management process is beneficial in allocating water based on spatial variability throughout fields and can sometimes conserve water and improve crop quality. Many field characteristics like topography, yield, and soil properties contribute to the spatial variations in irrigation needs throughout fields. Variable rate irrigation (VRI) for center pivots is a large part of precision irrigation as it can section out a field into zones or sectors to apply different irrigation rates based on the water needs of those specific areas.
Depending on the characteristics of a field, different approaches may be valuable for developing irrigation prescription maps. These approaches can range from using simple and accessible data to more costly but potentially very valuable data collection. A VRI system can be a beneficial management tool for improving irrigation efficiency with an understanding of the tools, time, and equipment needed for successful operation. In this fact sheet, we discuss the various VRI options for center pivots, when they might reduce water use and energy, produce higher crop yields, and when it might be unreasonable to expect these kinds of benefits.
What Is VRI? VRI is a technology used on agricultural irrigation systems to vary the water application rate and/or speed of the irrigation to cater to the different needs throughout a field. When fields have varying soil properties, topographical features, or crop density, a VRI system can provide the correct amount of irrigation to each area. This technology has been used with the goal of improving water and crop water productivity primarily on center pivot irrigation systems (O’Shaughnessy et al., 2019). VRI can be implemented by either speed or zone control.
1