Water is an essential input for agricultural success, but farmers cannot always rely on nature to deliver optimal amounts at the right time every season.
Farmers in Iowa have gone to great lengths to manage how much water is on and in their fields, as is evidenced by more than a century of use of drain tile systems and other practices designed to get water off the land during critical planting and germination periods. This focus on removing water has been the norm, but recent changes in weather patterns combined with greater awareness and focus on water quality has some farmers taking another look at handling drainage water — and when it make sense, recycling it.
"The concept of recycling water that has been drained off fields is not necessarily new, but some coincidental factors are beginning to heighten interest, particularly among those already using irrigation systems," says Matthew Helmers, director of the Iowa Nutrient Research Center and dean's professor in the Iowa State University College of Agriculture and Life Sciences. "Several years of drought conditions in parts of Iowa, combined with greater focus on nitrogen losses from farm fields, is getting farmers looking at new practices that can improve crop performance and downstream water quality."
POND CONSTRUCTION: This photo shows the construction of the drainage pond on Mark Schleisman's farm in Calhoun County. Schleisman constructed the reservoir pond to store the water from a 24-inch tile drain in spring 2021 in collaboration with the Iowa Department of Agriculture and Land Stewardship, Iowa Soybean Association and Iowa State University.
Helmers joined a water and agriculture experts nationwide on the Transforming Drainage team to study the idea of drainage water recycling, and produce educational materials and best practices for farmers across the Midwest.
The team has published a primary resource for those interested in learning more about this topic. "Questions and Answers About Drainage Water Recycling for the Midwest" is available for free download. The report offers this definition and benefits statement: “Drainage water recycling is the practice of capturing excess water drained from fields, storing the drained water in a pond, a reservoir, or a drainage ditch, and using the stored water to irrigate crops when there is a water deficit. Relative to conventional drainage, drainage water recycling has two major benefits: (1) increased crop yield and (2) improved downstream water quality.”
"Of course, this practice does require investment in one of several different systems for irrigation. But like tile, once installed, the systems are expected to last many years," Helmers continues.
Costs may include pond construction; conveyance and pumping systems; an irrigation system, such as sprinklers, pivots or subsurface delivery; as well as labor and design. Some costs may be offset by flood mitigation, water quality and other funding programs.
Yield improvement and cleaner water
Maximizing yield while managing input costs is the best path to profitability for most farms. Implementing drainage water recycling can help by providing the farmer with greater control over the timing and quantity of water applied to fields. Drainage water, collected primarily in the springtime, is stored and pumped back to the field when desired.
The advantage of storing water containing dissolved nitrate in a recycling reservoir is that those same nutrients are applied back to the fields at times when they can benefit cash crops — with no additional input cost. And water that does flow into waterways from the reservoir has reduced nitrate levels, providing cleaner water flowing downstream.
An Iowa case study
Mark Schleisman operates a farm in Calhoun County, Iowa, in the Raccoon River watershed. He is recognized by farmers and conservationists across Iowa as an innovator and first mover when it comes to conservation practices and working to minimize nutrient loss.
"We've been ratcheting up to help reduce nitrate loss for the last 10 years," Schleisman says. "Cover crops are a primary practice across our acres, and after learning more about edge-of-field practices and working with the Iowa Soybean Association, we installed four bioreactors and a saturated buffer to capture nitrate before it gets to the river."
Much of the land on Schleisman's farm is hilly; so when looking at a water recycling system, it was clear that subsurface backflow through the tile system was not practical. Opting for a new irrigation pivot and construction of a reservoir pond to store the water from a 24-inch tile drain, Schleisman installed the system in spring 2021 in collaboration with the Iowa Department of Agriculture and Land Stewardship, Iowa Soybean Association and Iowa State University.
"We are starting with our seed popcorn fields, looking for improved yields through more controlled water management and sidedress application of nitrate returned to the field with the water," Schleisman says. "We will be testing the water and looking to find optimal application rates both preplanting and throughout the season."
Schleisman anticipates an immediate return on his investment through lower water costs, looking to use the reservoir as the sole water source for these fields. He is also looking forward to additional savings on fertilizer.
As a farmer who has made a concerted commitment to conservation and improving water quality, Schleisman is eager to share the outcomes of this project in hopes that others will consider making the investment in helping to keep nutrients out of the water and in the fields.
"Of all the different conservation and nutrient loss prevention practices I've looked at or tried, this is the one that has the clearest potential to return something to the farmer. Drainage water recycling is not just doing what's right, but doing something that also makes us some money."
To learn more about drainage water recycling, visit transformingdrainage.org.
Staudt is a conservation outreach specialist with Iowa Learning Farms and director of Water Rocks.