September 11, 2003

 

Small Depressions May Need to be Leveled

Red River Valley producers may want to consider checking their shelterbelts to see if they still have their land planers. Growers in the valley have been noticing more and more depressions in their fields. They may not be very large but they do hold water that can cause crop damage, according to Joseph Giles, North Dakota State University soil scientist.

"It’s a naturally occurring problem," Giles says. "The Red River Valley has high clay soils that crack open during dry periods. Soil then falls into the cracks and is trapped there when rain falls and the cracks close. That may not sound like a problem but if it happens in the same area over a 15 to 20 year period, the trapped soil swells enough so that it is forced out and upward creating a small depression."

Years ago, before chisel tillage was recommended, producers would moldboard plow under their residue. Then they would go through the field with a land planer. The planer would effectively even out a field, eliminating the depressions.

"But as residue management farming became popular, producers no longer used the planers because of the plugging caused by the increased surface residue," Giles says. "Many ended up in shelter belts or were cut up to use as a grader for leveling farm yards."

Producers that use field-draining techniques have found that there are too many smaller depressions that won’t drain. "You have to remember that in the Red River Valley it doesn’t take much to cause a depression," Giles says. "All it takes is an inch or two of soil that is raised."

Giles is not advocating going back to plowing under the residue in the fall. He suggests that during crop rotations, when there isn’t a heavy residue left on the field, a land planer be used. "It takes longer than three or four years to build these depressions so when we have a situation where there is very little residue, producers should consider using a land planer," Giles says.

"Some growers have asked about deep-tilling the depressions. That creates a slot, which allows soil to fall to the bottom of the depression. If it rains it will aggravate or advance the development of the depression."

Land planers or levelers have become more sophisticated through the years. Some now use lasers for grade control. "But I think the one in the shelterbelt, if it’s still there, will probably work just fine," Giles says.

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Source: Joseph Giles, (701) 231-7858, joseph.giles@ndsu.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu