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Every drop counts
Irrigators turn to technology to make every gallon of water count toward yield.
The rest of agriculture could learn a lesson about efficiency from irrigators. They have been challenged to make ends meet going as far back to the 1970s oil embargo that caused their pumping costs to double in one year.
Fuel costs are still a concern. But today's challenge is the huge restrictions in the amount of water irrigators can apply to crops. In some locations of the High Plains, farmers have been cut back to withdrawing as little as 10 to 12 inches of water a year. That would be similar to being restricted to applying no more than 30 pounds of nitrogen on corn a year while trying to raise a 200-bushel crop.
So how are irrigators making water ends meet? By turning to technology. That explains why Roric Paulman's office looks like a NASA control center. With two large computer monitors lined up across his desk, Paulman can monitor every aspect of the 40 wells and center-pivot irrigation systems on his Sutherland, Nebraska, operation. Moreover, he has as much as or more weather data at his fingertips than the local TV station.
In Paulman's area, he says, “We rely on supplemental water to produce a crop.” He notes that the average annual rainfall is somewhere around 20 inches. “Water has become one of the primary inputs as far as cost is concerned. We figure it has the potential to cost $7 to $8 per inch per acre for irrigation,” he says.
But cost is only part of the issue. Equally important is conservation of the resource, as well as preservation of the aquifer and the rural economy, says Paulman, who is also vice president of the Nebraska Water Balance Alliance.
He has turned his farm into a showcase for new irrigation conservation technology. By working with stakeholders like the University of Nebraska, his area's natural resource district office, the local electric cooperatives, and various irrigation, seed and machinery companies, Paulman has already tested and implemented a variety of tools and techniques.
“It's estimated that the use of moisture sensors alone has the potential to save a producer about 2 inches of water, primarily at the first and last waterings,” he says. “That represents a savings of up to $16 per acre. However, if you multiply that 2 inches across all the irrigated acres in the Twin Platte NRD (his natural resource district), that's about 56,000 acre-feet of water that we could keep in the aquifer.
“Part of our goal, beyond finding ways to reduce water use, is to deliver producer models that other farmers can apply,” he adds. “About seven years ago, they designated this area of the Platte River Basin as overappropriated. As a result, the state has increasingly looked at groundwater to carry the burden of offsets.”
One way to do that, Paulman explains, was to require water meters at pumps and cut producers to 10 to 12 inches per year (or 60 inches over five years) and let producers manage their way out of that, depending upon the crop.
“The meters are a valuable tool,” he says. “But they really don't address a management strategy or help a rural area from an economic standpoint.”
Telemetry also at work
Since Paulman Farms is spread over a radius of approximately 26 miles, he insists one of the most valuable of the new technologies has been the soil moisture sensors that utilize telemetry and GPRS-based communication to relay information. For comparison, Paulman has soil moisture management units from all three of the main suppliers: AquaCheck, AquaSpy, and Crop Sense from John Deere Water.
Plus, he has them installed in various quantities within a pivot circle, as well as in grass, dryland wheat, and CRP acres as a means of comparison.
“Watermark sensors have been around for a while and still provide benefits. But this capacitance-based, continuous-logging technology that has emerged really has the potential to save water and money,” Paulman says.
At the same time, Paulman has begun relying on a network of five weather stations and 20 rain gauges spread across his operation to provide environmental data. In addition to rain events, each weather station also collects and charts 13 other weather-related assessments, including wind speed and direction, relative humidity, temperature, and even rain intensity, which can be a hint to whether the rain soaked in or ran off.
“If I'm sitting here in the office and see that it's raining 20 miles away, I can immediately shut off those units using remote-control features like Valley Tracker,” he says. “I can always run over there the next day and read the rain gauges in that area and decide whether to start the pivots up again.”
Like Paulman, Great Bend, Kansan Roger Brining has turned to technology to reduce water use.
Several years ago he invested $16,000 for a technology package that included moisture sensors. These were positioned in seven locations on his operation. The sensors will determine soil moisture conditions and then transmit detailed information to his office computer.
Brining also invested in a sub-surface drip irrigation system in an experiment to reduce water usage. This drip tape was buried at different depths to suit soil conditions.
For example, one field has the drip irrigation tape buried 16 inches underground on 60-inch centers. The soil moisture sensors in that field record moisture percentages at 8, 24, and 36 inches.
“We wanted to see if I could bring up corn yields in a soil (sandy type) that doesn't hold moisture well,” Brining says. “My other approach if that doesn't help will be to change strategy. I'll lower my yield goals and reduce seeding and fertilizer rates in that one area of the field to target a yield I can actually get.”
Ultimately, Brining's goal is to get the most bushels per unit of water.
“I'm not sure I'd be farming if I couldn't recognize the potential for reducing costs and increasing productivity with technology,” he says.