 When you think about the bottom line of your irrigation system, many questions come to mind. What is the cost to install the system? Where can I save money? When will I see a return on my investment? However, these are just the initial costs. Many people think this is the bottom line and don’t see the bigger picture of how small savings up front might impact your energy costs, loss of water and nursery crop yield over time.System selection depends on the nursery crop, topography of the site, water supply and desired profitability. There are many low-pressure sprinkler system options today requiring less energy and fuel that provide significant long term savings. In addition, these more efficient systems may qualify for financial incentives and rebates. A well-designed, installed and managed system is necessary for efficient water management. It is best to ask for the help of a certified irrigation designer. Application efficiency Irrigation application efficiency is defined as the amount of water applied that is in the root-zone and available for plant use. Irrigation system capabilities, plant water requirements, container plant spacing, container media water holding capacity, as well as the uniformity of irrigation water application impact the application efficiency. Distribution pattern or distribution uniformity (DU) is a measure of how uniformly water is applied to an area irrigated with overhead sprinklers. If the sprinkler system does not apply water uniformly, often the irrigation duration is increased, sometimes excessively to compensate for drier areas. This results in excess water applied in part of the irrigated area and leaches nutrients from containers. Uniformity is impacted by droplet size. Droplets must be large enough to resist wind drift and evaporation and small enough to be gentle on the crop. Pressure fluctuations effect sprinkler flow, droplet size and wetted diameter. In a 15 psi applicator, a variation of 1 psi can mean a 3.3 percent difference in flow, which causes the over- and under-watering of unregulated systems. The use of in-line pressure regulators helps maintain consistent outlet pressure regardless of variations. Sprinkler choices There are so many sprinkler choices to consider. Software is available to analyze various performance specifications before you buy to assure you have a design that meets the requirements for your specific installation. You should base the decision on performance and not price. When done correctly, system design produces a successful yield. With new software technologies available today comes the responsibility to use resources wisely. Water and energy savings are not only desirable, but mandatory. The focus on the initial cost of installation is no longer the bottom line. The real bottom line is in what can be saved—water, energy, soil quality—added to your increased crop yield from proper system design. Copy provided by Senninger Irrigation, which designs and manufacturers sprinklers, spray nozzles and pressure regulators for ag, nursery, greenhouse and land application of effluent; www.senninger.com. |
Explore the July 2011 Issue
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