Tile drainage 101

Underneath 50 million-plus acres across the nation are miles of tile quietly keeping fields in prime condition for growing crops.

Soils that tend to hold water longer, flat land that can’t shed water, and fields that have spots prone to saturation are suited to tile drainage. Depending on the issue, this practice enables the soil to act more uniformly.

Keegan Kult, executive director of the Ag Drainage Management Coalition, explains the basics of tile drainage and how you might create additional value by layering conservation strategies onto existing tile systems.

How it works

The tile is plastic tubing with perforations, buried between 3 and 5 feet deep. The perforations pull water that isn’t bound to the soil. Not only does that alleviate the saturation, but the oxygen in the water gets incorporated into the soil as it passes through.

Kult says that historically, farmers would tile only out to the identified wet spots in the field and add branches around to better drain the area.

“Now, we’re shifting more toward pattern tile drainage that has more uniformity with drain spacings and lateral tile lines anywhere from 40 to 80 feet,” he explains.

The 3- to 4-inch lateral lines feed into a main line that is 6 to 10 inches in diameter. That delivers water to a larger-scale county tile system, a surface ditch, or outlets to a stream.

Benefits to farmers

“The biggest incentive to install tile is yield,” Kult says. “It depends where a farmer starts out, but yield increases of 15% to 25% can be achieved with properly installed tile systems.”

There are several factors that contribute to a yield increase:

1. Access to fields. As we’ve seen before, weather doesn’t always cooperate during the crunch time of planting season. If it’s a wet spring and the window to get out into the fields is short, then drier soils mean you can actually get planting done.
2. Improved soil conditions and uniformity. Kult says drier soils are less likely to be compacted than wet. Compaction is often a long-term issue for affected farmland.
3. Consistently completed fieldwork. “Farmers might go out to a new part of the field and have to come back to finish it off if the field is too wet. With tiling taking care of the soil, you have better chances of doing it all in one go rather than having to wait for a section of the field to dry out.”

In addition, tiling allows farmers to shift gears and implement soil health practices.

“A lot of times, if a farmer has invested in a tile drainage system, we will hear that they switch to no-till management,” Kult says.

When tillage passes are used to help dry out a field to get the seedbed ready, tiling can serve the same purpose.

Kult says he has also seen benefits to cover crop establishment in fields that are tiled and less saturated. With a good foundation, they’ll grow better and have a more vigorous stand.

“That gives farmers the confidence to manage a cover crop when they need to in the spring to get their primary crop in place,” he says.

How to determine value

Many resources exist to help calculate cost and expected yield returns.

Kult recommends these tools as you get started:

• The “tools” option at transformingdrainage.org is great to help make decisions about site selection on controlled drainage/drainage water management: https://transformingdrainage.org/
• The price calculator and drainage design tools from Michigan State University: https://dsiweb.cse.msu.edu/demo/DrainSpacingCalculator/
• Ag Drainage Management Coalition, which Kult directs, has many useful resources as well: https://admcoalition.com/

Asking questions like “how much drainage do you need?” will inform the type of system needed. Work with contractors to create a plan and ensure it will work for your goals.

How tile is installed and maintained

One of the first steps to take if you’re looking into tiling, is to check on a wetland determination with your local Natural Resources Conservation Service staff.

While some farmers may consider installing drainage tile themselves, local contractors are available and are the best professionals to work with to ensure success.

To make long-term maintenance easier on you, Kult recommends making sure your main tile line is adequately designed to collect water from the laterals.

“It does get a little bit pricey when you’re installing the larger pipe, but it doesn’t do you any good to have a nice field of laterals and then an undersized main because that means it’s going to restrict water,” he says.

Check regularly for tile blowouts and sinkholes in the field, which may indicate cracked tile that needs repair. It may also indicate the tile is clogged with plant material. He also says to check the outlets if your tiling is directed into a drainage ditch or stream. Don’t allow them to submerge or fill with sediment.

Take the next step

Once tiling is in place, you have more options to add conservation and soil health practices on your land.

“When you’re thinking about designing a new system, that’s also the time to think about additional drainage practices that complement tiling,” Kult says.

In fields, that could be controlled drainage, which allows you to control the amount of water stored to use throughout the year.

“In Illinois and Indiana, there is a lot of drainage in the winter months and obviously we don't need to be draining water at that time because crops aren’t in the fields. Instead, we can be holding that water back,” he explains.

On the flip side of that, if there is a wet spring, controlled drainage lets you keep the water back to make available during summer.

In addition to the focus on soil health and greenhouse gas emissions reductions, it’s important to consider water management.

“In the Iowa Farm in Real Life Poll from Iowa State University last year, one question concerned how farmers deal with climate mitigation and change. The second-most popular practice was to upgrade existing tile drainage systems or install new ones to deal with risk,” Kult says. “We need to do as much as we can to help farmers realize that there are options available with tile drainage systems. These can improve the conservation side of things and production.”