BRANDON — Tile drainage may be the best solution to managing saturated soils, but the cost is prohibitive for many producers.
However, a low-cost mechanical mole boring temporary tunnels may serve the same purpose.
Imagine a torpedo-shaped four-inch diameter slug of iron being pulled through your field at a depth of two or three feet.
The depth and grade angle is GPS RTK controlled to make the mole passages carry water to the edge of your field. It’s a simple drainage device that’s been employed throughout the world for decades, according to mole manufacturer Hugh Hunt, who had his torpedo at Manitoba AgDays.
“The Europeans have had these for over a century. They call it a mole plow,” says Hunt, explaining that it works similar to tile drainage, but at a fraction of the cost. He adds that it only works in heavy clay soils and the cylindrical sub-surface water channels are temporary.
“We’ve taken that European concept and re-engineered it to work with our 500 horsepower tractors. We’ve set it up with RTK so we get very precise grade control. We do a topographical map and a drainage prescription map for a field, exactly like you would for tile drainage.”
The mole machine pulls a four-inch bullet, the depth of which is controlled by the hydraulic cylinders. Precise depth instructions to the hydraulic cylinders comes from the RTK system. It is also LIDAR compatible.
Hunt says the bullet follows along behind the single opener. The official engineering term for the bullet is expander because it expands the clay by forcing it outward to form the round tunnel.
“In Europe, the tunnels last eight to 10 years. We don’t know for sure yet how long the tunnels will last in North America because it’s a new idea here. We may have to go back in after five years to run it again, but you already have your RTK prescription map. That won’t change. So the cost isn’t great.”
He says deeper tunnels last longer. The bullet can bore accurate water passages down to a depth of five feet. Some European farmers use their mole to make tunnels which hook up to larger permanent drain tiles at field edge.
The mole is being developed and will be manufactured by Dave’s Machine in Oak Bluff, Man. Hunt farms at Hallock, Minnesota, and owns the Hunt Seed Company. The mole he had at AgDays was a prototype. He wants to do more testing before going into production with the final design. The initial target market will be the Red River Valley because it has tight clay soil and extreme excess water conditions There’s no indication yet what the price will be.