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For years, producers have looked for ways to manage the water on their fields.
The Greenley Research Center near Novelty, Mo., has turned to drainage water management in an effort to generate and regulate the amount of water in its fields. Research at Greenley began in 2001 with one drainage site and has seen continued, positive results. This initial research led to additional sites installed in 2009 and 2010.
Drainage water management is designed to keep nutrients in the field and send cleaner water downstream. It also reduces the amount of nitrate that can flow into ditches and streams. Too much nitrate can cause water quality problems.
“There have been several studies throughout the Midwest looking at drainage water management when it came to reducing nitrate loss,” Research Agronomist Kelly Nelson said. “We knew that drainage water management could reduce nitrate loss. We also knew it would be better than just free-flowing drainage.”
Nelson’s findings at Greenley have backed up those studies.
Based on the results, there was more than a 70 percent reduction in nitrate loss and an 80 percent reduction in phosphorus loss compared to the free-flowing drainage control.
Nelson said that Greenley collaborated with several contractors and engineers in 2001 to develop the drainage water management system. He said there were several small details they wanted to get 100 percent right.
“We had a lot of partners in 2001 – and we continue to have a tremendous group of collaborators and partners,” Nelson said. “I made a baseline drawing of what I thought we needed for research purposes, and the contractors made it work. We relied on them to make sure we had a quality installation.”
A handful of questions had to be answered when setting up Greenley’s first system.
“Understanding the soil characteristics – how fast the water moves through that profile – that helps you identify the optimal spacing for the drainage tile,” Nelson said. “Computer models indicated a 20-foot spacing was optimal and that‘s what we went with. We talked about 40-foot as well since most farmers will ask if they could go with a wider spacing since it’s cheaper.
“Also, because we’re on a claypan soil, we have a clay layer of subsoil that doesn’t allow water to move through very quickly. We’re trying to use that clay layer to our advantage when it comes to our drainage water management system.”
Nelson described the drainage water management structure as a box that is buried in the ground. It has different slides, or gates, in it that allows you to adjust the water table in that soil. Those structures are spaced out into water management zones based on the topography of the field. Once installed, Greenley then had more control over the water levels in their selected field.
“We put it in drainage mode, so water flows through it, in the spring to lower the water table,” Nelson said. “We want to get the crop established and get the roots growing down deep. As the crop gets to growing, we may put the slides down to conserve water in the profile. If we get another rain, we can hold that water back. If it is designed correctly and the topography allows, we put water back through the tile lines for sub-irrigation. Once we get into fall, right before harvest, we’ll let the drainage water flow again. Through the winter months, we put the slides down and basically shut off the valve. We allow the water table to get high. A lot of our nitrate loss comes during the winter months. If there is no flow, then we have no nitrate loss.
“Typically, we have a high water table in the fall and spring months due to increased precipitation. That’s usually when water can be most detrimental to crop growth and can cause soil compaction. We looked at putting water back through the system for sub-irrigation purposes because we typically dry out through the summer months. We’re utilizing those control structures to hold water in the field. We’re pumping supplemental water back into the control structures to raise the water table. With this system, we were able to evaluate yields due to drainage or drainage plus sub-irrigation.”
Using the drainage water management system for sub-irrigation also has increased yields in both corn and soybeans.
In corn, there was a 20 percent increase in yield with the drainage-only treatment. Using the drainage plus sub-irrigation, corn yield increased 45 percent.
The soybean yield also has been solid. There was a 20 percent increase in yield with the drainage-only treatment. There was a 25 percent increase in yield with the drainage plus sub-irrigation treatment.
Both of those increases are compared to not using drainage or irrigation.
With steady success in hand, Greenley is looking to expand its management of water on its fields.
Greenley Superintendent Dana Harder said they plan to put in a large-scale drainage water management system in 2017 in collaboration with the Missouri Land Improvement Contractors of America and Natural Resources Conservation Service at the recently donated 240-acre Grace Greenley Farm.
“The Grace Greenley Farm allows us the opportunity to implement drainage water management on a large scale and address some additional research objectives,” Harder said. “We will be creating a significant-sized lake to capture the water that comes off the field and tile lines. We’ll use that water source to sub-irrigate through the tile lines. It’s a closed-loop system.”
Nelson has also lent his expertise to a project through Purdue University. The Transforming Drainage Project provides information about drainage water management in the Midwest.
Greenley is planning drainage presentations for future events as well.