LIVINGSTON COUNTY, Mo.—An increased use of agricultural drainage tile is one reason a 2025 deadline to reduce nitrate and phosphorus entering the Gulf of Mexico by 20% is unlikely.
Drainage tile, a system farmers use to drain water from croplands, is also a contributor to the historic loss of up to about 100 million acres of wetlands in the U.S., researchers say.
This hidden underground pipe system stretches over more than 50 million acres in the U.S., with about 84% of those acres in the upper Midwest. It has become essential to modern agriculture, but it brings devastating environmental consequences.
About 98% of drainage tile in the nation is located in watersheds with excess nitrate and phosphorus levels. Tile changes the natural movement of water, serving as a conduit for pollution that is flushed quickly into nearby waterways.
Drainage tile is the “main delivery mechanism for nitrates from farm fields to the stream network,” Chris Jones, a retired hydrologist from the University of Iowa, said.
Before tiles existed, a raindrop might take decades to reach a stream network, Jones explained. “Now it’s hours or days.”
And researchers and agriculture industry experts say the problem is only getting worse. As climate change drives wetter weather in the Midwest and farmers push for greater productivity, many observers agree that drainage tile use is increasing.
Yet in many states, tile goes unmonitored and unregulated. Since tiles are considered a nonpoint source of pollution, which comes from places like farms where water isn’t tested, they also fall outside the reach of the Clean Water Act.
‘Bottom Line Is We Have to Make Money’
For many farmers, the math is simple. Tile costs about $1,850 to $3,700 per acre, an up-front investment that can increase annual crop yields by 5% to 25%.
Tile installers bury a system of connected drain pipes under farm fields to transport water to an outlet or ditch. The drains suck excess water out of the soil, giving plants room to breathe and allowing farmers to work their fields sooner.
For AG & Water
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