Subsurface drainage systems are no longer a technology reserved for the vague fields “up north” or a write-off in good growing years or bragging rights for “fancy” farmers.
Tile drainage systems are higher technology and lower input than ever before and they’re being installed in fields much closer to home than you’d think.
During the Stateline Crops Conference, a virtual collaborative effort between University of Missouri and Kansas State University, MU research agronomist Kelly Nelson shared his experiences and research in the field of tile drainage.
“We don’t have a lot of sub-surface drainage in the state of Missouri, although we are seeing an increase in subsurface drainage in Missouri and Kansas,” Nelson said.
Farmer interest in tile drainage is indicated in University of Missouri surveys dating as early as 1914. The technology took off in isolated areas without widespread adoption, potentially due to difficult installation and prohibitive costs.
Nelson said tile drainage has come along way when it comes to land surveying technology and the efficiency of installing drain tile.
“Back in the day it was actually a clay tile and we have progressed to a very efficient corrugated perforated plastic,” Nelson said. “Today, it can be installed very efficiently.”
Types of Tile Drainage
Tile drainage — like any on-farm system — comes in a wide variety of shapes, sizes and costs. There are three primary types of field-level drainage that use a tile-based system.
• Free drainage allows water to flow through the tiles and out of the field 24/7. With free drainage the goal is simply to lower the water table in the soil profile and keep the field from becoming or staying overly saturated.
• Controlled or managed drainage uses a water control structure to hold water in the field when drainage isn’t necessary. It’s a more complex system than free drainage but it increases water retention in the soil profile. Some Missouri soil and water conservation districts offer cost-shares for producers implementing these kinds of systems, so check with a local office.
• Drainage water recycling captures and reutilizes water for irrigation purposes with the added benefit of retaining and reusing excess nutrients and fertilizer.
Subsurface Drainage Layouts
• Interceptor Drains are normally used to drain hillside seeps and are installed parallel to the slope above seepage area.
• Random systems target just the wet areas of the field. • Herringbone systems target low areas of the field or a wet swale.
• Parallel systems are the most common throughout the Midwest and drain the whole field as well as providing controlled drainage and sub irrigation. In layout decisions there is no “one size fits all” approach. Each field comes with its own challenges from topography to soil type, field location and everything in between. Regardless of the type of system, budget-savvy producers will be hoping to achieve their desired layout with as few connections as possible.
“The main thing to keep in mind is the more connections we have, the more connections of these laterals to these main lines, the more the cost,” Nelson said.
In the longrun, Nelson said the key idea behind subsurface drainage is not to make the soil dry, it’s too keep the soil from becoming and staying overly wet.
“With subsurface drainage, the system is designed so we take that soil from saturated conditions down to field capacity,” Nelson said. “I always get questions about if draining the soil takes away so much water the crop won’t grow, but if you have too much water it won’t grow anyway.”
Nelson said the usability of tile drainage systems is not confined to seasons with high rainfall. Throughout much of southern Missouri and Kansas soil temperatures allow water movement all year.
“We see some of our fields have water flow all through the winter months because the soil doesn’t freeze hard enough or deep enough in these areas,” Nelson said.
Typically in the area of Missouri Nelson researches, tile drainage systems are installed anywhere from three to four feet deep and between 20 and 40 feet apart.
If the distance to cover is 40 feet, spacing the tiles closer together at 20 feet allows the field to drain faster. On the flip side, spacing the tiles at 20 feet means more connections and more cost, so identifying goals and developing a field-specific plan are crucial steps for making sure tile drainage is a feasible option for the individual operation.
“We know that some place in Missouri or Kansas, we face challenges with too much water year in and year out,” Nelson said. “The biggest thing is trying to design systems that increase the resiliency of our production systems.”
Two farmers and tile drainage installers shared their experiences with tile drainage, both on their own farms and on the farms of their customers. Rusty Johnson farms and operates Field Max Water Management services in southwest Missouri and has more experience working with local soil types.
“Our consensus for what we’ve seen in Southwest Missouri is that we lose more yield to a cool, wet spring than we do to even dry, droughty weather,” Johnson said. “We’ve installed a lot of pattern tile at 40-foot spacing in the silt-clay soils and we’ve also installed some sub-surface irrigation at 20-foot spacing. Both have their place.”
Johnson conducts some on-farm research in small plots on his own land and has several years worth of findings. He has been installing tile drainage systems since 2014.
“I’ve got a 20 acre field that’s split with 10 acres drained and 10 acres non-drained,” Johnson said. “We see anywhere from about a 20% to 30% corn yield increase in the drained field.”
Personally, Johnson has chosen to space out adopting tile drainage on his own operation to spread the costs out over time.
“What we've done to break up the cost over multiple years is pick out 40 acres, 80 acres,” Johnson said. “We go with whatever fits the worst case scenarios to start with, because obviously we've got spots that are drowning out every year.”
Depending on field yield and commodity prices, the return on investment for tile drainage could come quickly.
“We're going to see a 30 bushel increase on corn — a 30 to 50 bushel on just drainage,” Johnson said. “So if commodity prices are at $4, you're looking at $120 to $200, an acre increase for a system that on 40 foot spacing is going to take you anywhere from probably four to 10 year period to, to pay for itself.”
Fredonia farmer and tile drainage installer Glen Wydell has a background in both production agriculture and excavation which lend long-term experience to his tile drainage projects along the Verdigris River.
“We live in a very rocky area here, and we have some river bottom ground that has no rocks and some upland that can have sandstone or limestone,” Wydell said. “We design our systems to sort of work around rocky areas.”
While Wydell can probe into the rock to address problem areas in the field, some areas aren’t conducive to tile drainage systems. Slab limestone isn’t a big problem and sandstone can be worked with but Wydell said fractured limestone can cause issues.
The pieces get pulled into the pipes and bog down the whole system. Upper tiers of the soil profile can be problematic as well, especially in fields with compaction built up over time.
“When you have compaction on the surface the water is going to pond up, so you need to get that ripped out of there,” Wydell said. “The best way would be with cover crops and in some type of a root plant, like radishes or turnips, to break up your soil on the top and get that water and filtration rate to increase. Because if the water doesn't get to the tile, it's just not going to do you much good.”
For more information on drainage solutions visit transformingdrainage.org.