By now, the drought problems out West have caught the attention of producers across America. Even in Missouri, water deficiencies have caused farmers to look to irrigation, but many are unaware they could be losing a lot of water through some systems.
A new idea that has helped some producers in dryer states is subsurface irrigation. In Missouri, some have adopted efficient tile drainage systems, but the installation of drip irrigation hasn’t become a regular management strategy. Research Agronomist Kelly Nelson looks to change that with a study just getting its feet wet at Greenley Research Center in northeast Missouri.
At the center operated by the College of Agriculture, Food and Natural Resources (CAFNR) at the University of Missouri researchers will install subsurface drip irrigation to see how it effects crops and help control water loss.
The study will compare yields of corn and soybeans from the drip systems to non-irrigated plots and conventional overhead sprinklers. Research also will benefit farmers to know more about proper installation of the equipment, system design, pump and filtration requirements and possibility of injection systems such as fertilizer and other fertility applications.
“We want to find the best ways for you to install these systems,” said Nelson at Greenley’s Field Day on Aug. 5. “That may involve finding a dozen ways not to successfully install and use this system, but that’s the kind of research we like to do here. Research that benefits the farmer.”
Subsurface drip also could be used for providing water to crops on irregularly shaped fields and hillier slops. The area at Greenley being studied has 4 percent grade or more and the drip will be installed on the contour.
“This research is important to determine the production benefits, water use benefits and opportunities for subsurface drip irrigation,” said Nelson.
If You Build It, Yields Will Come
Lines will be installed at 5-, 7.5-, 10- and 15-feet spacing in the research plot. Water will be feed through a pressurized system from the nearby 18-acre lake with main water lines to feed water to the drip lines.
As the water is fed from the lake, a disc filter will ensure clean water. A 3-inch line will supply water to each supply line and a flush line will help water flow and allow the system to empty out if needed.
The drip lines will be dug no more than 2 feet into the soil to ensure protection from rodents and to stay above the impermeable claypan and attached to the feeder lines. Every 24 inches a regulator will be added to help control pressure of around 15 P.S.I. that will allow water to filter into the soil.
“The distance of how long these lines can run will mainly depend on your slope,” said Nelson. “We also may need to space these lines out even further based on lateral water flow. Most studies have shown 5 feet is the best spacing, but we really want to know if that’s best for different slopes or soil types.”
In other studies, subsurface drainage and integrated water management systems have been shown to increase yields. Techniques such as tile drainage and drip installed on flat, poorly drained soils have seen soybeans produce 9 to 14 bushels more per acre and corn yields can be increased 25 to 55 bushels per acre. On slopes up to 3 percent, corn and cotton yields in Georgia have increased 45 percent with drip lines on 6 feet spacing compared to non-irrigated fields.
“You also can see a reduction in the amount of water you need,” said Kelly. “Subsurface drip can reduce water use by 25 percent compared to sprinkler irrigation. You also are using smaller amounts of water that can be applied more regularly to avoid crop stress. Instead of mimicking a couple inches weekly, you can add even less than an inch more frequently.”
With subsurface drip irrigation, producers can see up to 95 percent water efficiency. With center-pivot irrigation growers are able to achieve 80 percent efficiency. Furrow irrigators reach only 50 percent efficiency, meaning half of the water is lost to evaporation.
“There is concern about the installation costs, but our research will help determine the economics of these systems,” said Nelson. “You can expect about $1,200 an acre on costs. Research has shown those lines will need to be in for about 10 years before you recoup your costs.”
On highly erodible soils, good surface drainage reduces the impact of excessive water on crop production. However, providing adequate water in a limited water supply environment could provide tremendous returns and production stability on Missouri soils.
“It’s exciting to have cutting-edge research available for people,” added Dana Harder, superintendent at Greenley Research Cener. “This research is all about new ways we can operate more efficiently.”
“We have to keep conservation more in our minds if we want to keep continuing production in the long run, said Nelson. “The goal isn’t to necessarily use less water, but to get more production with the water that is available and waste less.”
For more information about Greenley Research Center, visit their new website at http://greenley.cafnr.org/. Greenley is one of CAFNR’s Agricultural Research Centers located throughout Missouri that host educational workshops. Visit http://cafnr.org/events/ for more events located across the Show-Me State.
To download press-quality photos from Nelson’s talk, visit CAFNR’s Flickr site at http://bit.ly/GreenleyDrip. For photos of Greenley Research Center, visit http://bit.ly/GreenleyPhotos. Images from the 2014 Greenley Field Day can be found at http://bit.ly/Greenley14.