The Variable Rate Irrigation Management Challenge

Author(s):  
James Lowenberg-DeBoer

The potential for variable rate irrigation (VRI) is an approach to making better use of scarce water. Intuitively it makes sense to apply irrigation water when and where it will provide the most benefit, but implementing that simple insight is complicated because water control is costly. Experience with mechanically movable sprinklers suggests that current VRI technology can allocate water accurately in time and space, but knowledge of how to profitably manage such systems is lacking. The variable rate fertilizer experience suggests that farmers, public sector researchers, and the irrigation equipment industry should collaborate in on-farm trials that would determine profitable management with current technology and the improvements needed to make VRI standard practice for irrigators. Simultaneous with the on-farm analysis of VRI profitability on sprinkler irrigation in the industrialized countries, research should start on adapting VRI technology to smallholder farmers in the developing world.

2019 ◽  
Vol 35 (6) ◽  
pp. 837-852 ◽  
Author(s):  
Susan A O’Shaughnessy ◽  
Steven R. Evett ◽  
Paul D. Colaizzi ◽  
Manuel A Andrade ◽  
Thomas H. Marek ◽  
...  

Abstract. Variable rate irrigation (VRI) sprinklers on mechanical move irrigation systems (center pivot or lateral move) have been commercially available since 2004. Although the number of VRI, zone or individual sprinkler, systems adopted to date is lower than expected there is a continued interest to harness this technology, especially when climate variability, regulatory nutrient management, water conservation policies, and declining water for agriculture compound the challenges involved for irrigated crop production. This article reviews the potential advantages and potential disadvantages of VRI technology for moving sprinklers, provides updated examples on such aspects, suggests a protocol for designing and implementing VRI technology and reports on the recent advancements. The advantages of VRI technology are demonstrated in the areas of agronomic improvement, greater economic returns, environmental protection and risk management, while the main drawbacks to VRI technology include the complexity to successfully implement the technology and the lack of evidence that it assures better performance in net profit or water savings. Although advances have been made in VRI technologies, its penetration into the market will continue to depend on tangible and perceived benefits by producers. Keywords: Center pivots, Crop water use efficiency, Irrigation, Management zones, Moving sprinkler irrigation systems, Precision irrigation, Sensor based systems.


2010 ◽  
Author(s):  
Allen L Thompson ◽  
Kenneth A Sudduth ◽  
Joseph C Henggeler ◽  
Earl D Vories ◽  
Andrew D Rackers

2015 ◽  
Vol 33 (3) ◽  
pp. 167-175 ◽  
Author(s):  
K. C. Stone ◽  
P. J. Bauer ◽  
W. J. Busscher ◽  
J. A. Millen ◽  
D. E. Evans ◽  
...  

2019 ◽  
Vol 35 (6) ◽  
pp. 881-888
Author(s):  
Kenneth C Stone ◽  
Philip J Bauer ◽  
Gilbert C Sigua

Abstract. Site-specific variable-rate irrigation (VRI) systems can be used to spatially manage irrigation within sub-field-sized zones and optimize spatial water use efficiency. 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 with uniform irrigation management to maintain soil water holding capacity above 50% depletion using two irrigation scenarios: 1) a standard 12.5 mm irrigation per application; and 2) an application to refill the soil profile to field capacity. A 21-year simulation study was carried out on a selected field with varying degrees of soil and topographic variability. The simulated field had 12 soil mapping units with water holding capacities in the top 0.30-m ranging from 42 to 70 mm. The 21-year simulation covering all weather conditions for each soil produced only two significantly different irrigation management zones for scenario 1, and for scenario 2 only one management zone. However, when the 21-year period was divided into periods with different ratios of rainfall to reference evapotranspiration, the simulations identified 1 to 5 management zones with significantly different irrigation requirements. These results indicate that variable rate irrigation system design and management should not be solely based on long term average weather conditions. Years with differing weather conditions should be used for potentially identifying management zones for VRI systems. Irrigation application depths between management zones ranged from 17 to 38 mm. However, when the actual soil areas of the study field were utilized to calculate the total volume of irrigation water applied, it resulted in an increase in water usage in the 2 and 4 management zones ranging from -1.2% to 5.8%. Water usage with VRI over uniform irrigation was greater by -1.6% to 6.8% in the 12.5 mm irrigations and by -1.2% to 2.2% for the field capacity irrigations Keywords: Management zones, Precision farming, Variable-rate irrigation, Water conservation.


2010 ◽  
Author(s):  
Kenneth C Stone ◽  
Philip J Bauer ◽  
Warren J Busscher ◽  
Joseph A Millen ◽  
Dean E Evans ◽  
...  

2021 ◽  
Vol 24 (s1) ◽  
pp. 8-11
Author(s):  
Andrea Szabó ◽  
János Tamás ◽  
Attila Nagy

Abstract Nowadays, the development of irrigation is increasingly recognized as a necessary factor in agriculture, primarily because of global warming. Depending on the field conditions, the most commonly used method is sprinkler irrigation. The spray uniformity of sprinklers installed on the field irrigation equipment can be characterized by the Christiansen-uniformity coefficient (CUc%) and the distribution uniformity coefficient (DU%). Our investigations were carried out on the lateral moving irrigation equipment of University of Debrecen, Institutes for Agricultural Research and Educational Farm and Nyírbátor’s company in Hungary in 2019. Variable rate irrigation (VRI) is used in Nyírbátor. In contrast, the VRI has given positive results, making an irrigation equipment with the VRI a safer and more uniform method than a conventional linear irrigation equipment.


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