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200 bushels on 12 inches
A year in which the area is experiencing record drought certainly isn’t the time to cut back on irrigation. But that hasn’t stopped Harold Grall from trying to reach his ultimate goal of 200 bushels of corn on 12 inches of irrigation water.
With 4,500 to 5,000 acres of continuous corn under nearly 20 center pivots north of Dumas, Texas, even Grall admits it’s a lofty goal – especially when current yields average around 230 bushels per acre on nearly twice as much water.
“The 12/200 initiative was started in 2010 by the North Plains Water District,” says Grall, who is the junior director of the district. “That came in response to a directive from the state of Texas to predict how much water we would have left in 50 years. Of course, that also set into motion pumping allocations, which have been steadily decreasing every few years.
“We started four years ago with a 24-inch allocation,” he continues, “And 2011 was the first year for an 18-inch quota. The next step down will be 16 inches.”
Grall doesn’t know if and when the allocation will drop to 12 inches, but he and some of his neighbors want to be ready.
“Instead of just using legislation, let’s use education and prove what we can do with less water, which will help people feel better about cutbacks,” he says, noting that he and about eight other farmers have initiated a program to maintain production with less water.
Here are five water-conserving practices Grall has already initiated:
• Nearly 18 years ago, he began switching from ridge-tilling to his current strip-tilling, including the cotton that is often rotated with wheat on the pivot corners.
“We try to maintain as much residue as possible to reduce evaporation from the heat and wind. That, in itself, has made as much difference as anything,” he says.
• Plant populations that were once derived from around 32,000 seeds per acre have been decreased to 22,000 to 24,000 plants per acre.
“That didn’t happen all at once,” he says. “It’s changed over several years of seeing how plant populations affected yields and water use, and by looking for the best balance.”
• At least one moisture probe is located in each field to measure moisture levels in the root zone down to 60 inches. Rented from AquaSpy on a subscription basis, the units transmit field data from each unit directly to Grall’s computer or mobile phone.
“We can actually see the moisture levels decrease as the plant matures,” he says. “The probes measure moisture every 4 inches, so we can also follow the roots down and tell when they hit the next moisture zone.”
• Early irrigations are delayed as late as possible to force roots to penetrate deeper into the soil profile. Too much water too early causes roots to spread out, while excess moisture moves past the root zone.
•While it isn’t a normal practice, Grall says he delayed corn planting on his demonstration plot until the first week of June in hopes that every day of delay would be that much closer to a rainfall. In most years, though, he plants corn in April and early May.
“It’s not just a matter of conserving water to meet allocations,” Grall says. “It costs at least $5 per acre for every inch of water we apply, with the price going up a little more every year.”