Issue link: https://www.e-digitaleditions.com/i/1159340
12 A L M O N D O R C H A R D 2 0 2 5 G O A L S WATER USE Continued from Page 11 THE IMPORTANCE OF DISTRIBUTION UNIFORMITY Contributed by Jim Anshutz, AgH 2 O Drip/micro-irrigation is currently used on over 3 million acres in California, a large portion of which are nut crops. While drip/micro-irrigation systems have the potential for efficient application of water and fertilizers, many of the existing systems are operating well below their intended capabilities. Most systems are well- designed, use equipment of the highest quality and are "time tested" in the field — yet they continue to underperform. Less than optimum performance of these systems, therefore, is typically due to one or more of the following: Plugged emission devices due to lack of chemical treatment of the irrigation water and/or insufficient system maintenance, System pressure variations due to lack of proper control of system pressures throughout the distribution network, Degradation of the above-ground system components, other than the emission devices, such as pumps, filters, pressure regulating or sustaining valves, air vents and irrigation block control valves, Improper scheduling of the timing and duration of irrigations to replace water extracted by the crop from the effective root zone. That's where the importance of distribution uniformity (DU) comes in. DU is important because it provides a measurement of how evenly water is distributed across the orchard. To determine an irrigation system's DU, growers should receive a complete irrigation system evaluation, including a DU and system component performance test. The evaluation must be performed by a trained technician who cannot only determine the DU and the current system component performance, but who can also recommend solutions to improve any reduced performance. Evaluations lead to more efficiencies Many growers believe that the cost of a complete irrigation system evaluation and the proposed solutions to improve the overall performance cannot be justified. However, with increasing water costs, water availability concerns due to regulation or lack of supply, and rising energy and fertilizer costs, growers would be remiss not to take a closer look at the costs for improving overall system performance. Realizing that every field differs based on location, water supply, soils, climate, irrigation system design, etc., the accompanying graph and analysis This is a limited, simple economic justification of improving the drip/ micro-irrigation system efficiency performance from an existing DU to a minimum new system DU of 90%. A complete irrigation evaluation of a grower's unique system should be performed by a certified professional to ensure a complete, true return on investment calculation. Return on Investment in Years 2 3 4 5 $1,800 $1,600 $1,400 $1,200 $1,000 $800 $600 $400 $200 $ 70% DU 75% DU 80% DU 85% DU Jim Anshutz Owner and Founder AgH 2 O