The balancing act required to manage precious irrigation water resources, and to insure that plants receive enough to reach yield goals without wasting or spending too much money on pumping, gets ever more precarious for Southwest farmers.
Many have converted irrigation systems — furrow to pivot; pivot to LESA or LEPA; pivot to subsurface drip — and are continually upgrading nozzles, application timing, crop selection, and tillage to improve efficiency.
At the Texas Plant Protection Association annual conference at Bryan, discussions centered on new wrinkles available to manage water more efficiently.
Mike DeFrank, Jain Irrigation, says monitoring moisture demand and scheduling applications are essential factors in using water to maximize profitability, and tells about two systems he says could help Southwest farmers use water better.
“PureSense is a monitoring and software system that gives producers visibility of irrigation and chemigation, as well as other environmental and irrigation system inputs. This allows them to manage their crops as acreages and distances expand.”
MORE TIMELY USAGE
He says PureSense helps reduce input costs by using water and fertilizer in a more timely manner. Software allows producers to include weather station data and crop soil moisture in various management approaches to maximize crop yield, irrigation efficiency, and plant and soil health.
The system includes field configurations to determine best approaches. “Some fields could have eight or nine different requirements for nitrogen and other inputs, depending on the crop,” he says. “The system can monitor anything, including irrigation system valves.” Producers get scheduling reports to help make irrigation timing decisions.
GeneSys, a new sprinkler, is “self-contained, self-powered by solar energy, and has two-way communication capabilities that allow growers to use variable rate precision technology to apply irrigation and chemigation to their crops,” DeFrank says. Growers can customize sprinkler revolution speed, droplet size, and wetting pattern diameter.
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Field tests will continue in 2016. The sprinkler system allows producers to manage fields according to specific zone needs, and considers farmer input such as soil type, crop, fertility requirements, field sensor data, and imaging data.
The system responds to nutritional needs, DeFrank says. “Each sprinkler is controlled independently, so producers can write a prescription for any part of a field and for any practice.”
Danny Sosebee, Netafim USA, says a new offering, a precision mobile drip irrigation (PMDI) system, offers the lower installation cost of pivot irrigation with the efficiency of subsurface drip.
A MORE EFFICIENT SYSTEM
“Drip irrigation is the most efficient irrigation system,” he says. “It is also the most expensive to install.” PDMI uses a drag hose with emitters similar to those used in drip irrigation tape, installed onto a center pivot irrigation unit. “It’s a pressure-compensated drip line that’s designed for each pivot, according to flow,” Sosebee says. “PMDI takes advantage of the mechanical components and ease of installation of a center pivot, along with the crop benefits of drip, including higher water use efficiency and maximum fertigation and chemigation advantages.” He says water use efficiency is improved by 28 percent to 33 percent over traditional pivot units.
The hose is 50 mil black or orange tubing. Emitters are placed every 6 inches along the tube. The tube applies water precisely on top of the soil. Tubing can be attached to either a high water line or a low line.
The system may be used as either a traditional pivot system or as a PMDI with the tubing attached, Sosebee says. “Producers may need sprinklers to germinate seed, and they may need special equipment to fertigate and chemigate.”
The tube follows the pivot down circular rows. “It works best on flat ground — you don’t want to pull the hose across peaked beds. Emitters deliver water and nutrients to targeted areas, with improved infiltration rate. With low impact, we see little soil compaction.
“PMDI is not for everyone,” he says. “Farmers with wells of 100 gallons to 400 gallon per minute capacity are good candidates. It can provide 20 percent to 50 percent water savings. We think growers may see better yields with the same amount of water.”
Some producers may need filtration systems for the PMDI systems. “And they may need to treat water for algae,” Sosebee says. “The system will last about five years — not as long as subsurface drip irrigation.”
Farmers may qualify for Natural Resources Conservation Service funding through the Environmental Quality Incentive Program (EQIP), he says.