The Variable Rate Irrigation Management Challenge
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.