This story also appears in our University of Missouri College of Agriculture, Food and Natural Resources’ Agricultural Research Center Magazine. Stop by your local Research Center to pick up a copy!
For nearly 20 years, the University of Missouri College of Agriculture, Food and Natural Resources’ Greenley Research Center, near Novelty, has worked to help local farmers manage the water on their fields.
Greenley has turned to drainage water management in an effort to 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 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 and the effects on reducing nitrate loss,” said Kelly Nelson, an agronomist at Greenley. “We knew that drainage water management could reduce nitrate loss. We also knew it would be better than just free-flowing drainage, but we didn’t know the extent of the reduction in loss.”
Nelson’s findings at Greenley have backed up those studies.
Based on the results, there was a 70 percent reduction in nitrate loss and an 80 percent reduction in phosphorus loss compared to free-flowing drainage control.
“Water management is critical,” Nelson said. “The biggest thing farmers commonly deal with is too much water in the spring and not enough water in the summer. We wanted to implement systems that not only benefit yield but are environmentally sensitive, too. We have a real opportunity to get these systems designed and implemented with nitrate management in mind.
“A lot of our research is site specific. We have to focus on the soil type – that really governs everything. Water availability is another issue we look at. There is a lot that goes into those decisions.”
Nelson said Greenley collaborated with several partners in 2001 to develop the drainage water management system. He said there are several small details that they wanted to get 100 percent right.
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 the soil – that helps you identify the optimal spacing for the drainage tile and it helps guide the depth for installation,” Nelson said. “Computer models indicated a 20-foot spacing was optimal and that‘s what we started with. We talked about 40-foot spacing as well since most farmers are interested in going 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, which is part of a drainage water capture and recycling system.”
Nelson described the drainage water control structure as a box that is buried in the ground. Inside the box, there are different slides in it that allows you to adjust the water table in the soil. Those structures are placed into water management zones based on the topography of the field. Once installed, there was more control over the water levels in the field.
“The system is placed in drainage mode, so water flows through it, in the spring to lower the water table in the soil profile,” Nelson said. “We want to get the crop established and get the roots growing down deep. As the crop starts to grow, 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, we can 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 compaction can result when soils are worked too wet. We have evaluated putting water back through the system for sub-irrigation purposes because we typically dry out through the summer months. We’re pumping supplemental water back into the control structures to raise the water table. We have been able to evaluate crop yield response to drainage and drainage plus sub-irrigation yields.”
This was the first system of its kind evaluating corn and soybean response in Missouri.
Using the drainage water management system for sub-irrigation has also 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 has also 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.
“There have been a lot of great partnerships which have allowed these projects to come together,” said Dana Harder, superintendent at Greenley. “It was important to have the expertise of the contractors and engineers involved in the development of our system. Some of this was definitely outside of our knowledge base and it was important to make sure the research was practical.”
According to other research conducted at Greenley, when soils are saturated for a prolonged period of time, at the V6 growth stage in particular, there can be a loss of six to 12 bushels per acre per day.
“With drainage water management, we can minimize that loss and have been able to plant earlier at times,” Nelson said. “We know the challenges and the issues, and we know that there are risk aspects. We can do everything right when it comes to crop management, but Mother Nature always rules when it comes to water management unless we can improve water management systems.
“But when you look at drained soils versus soils that are not drained, there’s a night and day a difference.”
Since the establishment of its drainage water management research, the Greenley Research Center has become widely recognized for its excellence in handling water management issues.
The Center has researched a variety of integrated water management systems, including free drainage, controlled drainage, drip irrigation and drainage plus sub-irrigation. With steady success in hand, Greenley is also looking to expand research on management of water on its fields.
A new lake was established in 2017 in collaboration with the Missouri Land Improvement Contractors of America (MoLICA) and the USDA Natural Resources Conservation Service at the recently donated Grace Greenley Farm that will serve as a drainage water capture and recycling site which will build on current research.
“Water that comes off the field will be captured in this lake,” Harder said. “We’ll use that water source through the tile lines to sub-irrigate. It’s a closed-loop system.”
Nelson has also lent his expertise to a project, Transforming Drainage, which includes several states throughout the Midwest. The project provides information about drainage water management as well as drainage water capture and recycling systems in the Midwest.
Greenley is planning drainage presentations for future events as well.
“There’s still a lot more to be done, but when it comes to production, we need to produce more for a growing population – and be sustainable while we do it,” Nelson said. “We think these innovative systems that manage the water on the fields can be a part of that process.”