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Super-Sized Equipment Not Suited for Highly Erodible Ground

by Jason Johnson, Public Affairs Specialist, USDA-Natural Resources Conservation Service

A northwest Iowa farmer plants up and down the hill on the highly erodible loess hills.Iowa’s soil and water conservation advocates are asking farmers to match machinery size with their conservation needs when farming Iowa’s steep slopes. Large, wide equipment is often difficult to maneuver around many of Iowa’s traditional conservation practices, causing many farmers to reduce or eliminate conservation where it is most needed.

Dr. Mark Hanna, Extension agricultural engineer at Iowa State University, says farmers need to consider what is best long-term for the land they farm. “In sloping areas that benefit from contouring, it is often not practical to use wide equipment used in flatter areas,” he said. “Tighter turns nearer the top of slopes can minimize the capacity effects of equipment that is too wide.”

For decades, Iowa farmers have been planting crops along the contour, instead of up and down slopes, and implementing other erosion control measures on their farms to help reduce the risk of soil erosion and prevent crops from washing away. But, as farmers work more acres and upgrade to larger equipment to improve efficiencies, conservation methods and structures, like grassed waterways and terraces, are all too often perceived as production obstacles rather than necessary tools to protect the environment and long-term sustainability.

Erosion causes soil to degrade over time, which can substantially decrease the soil’s productivity. This stems from reduced topsoil depth, organic matter, and nutrient availability. Unproductive soil can also lead to an increase in inputs, costing the farmer money long-term and increasing the risk of nutrient runoff or leaching.

Use Smaller Planters
LuAnn Rolling, district conservationist with USDA’s Natural Resources Conservation Service (NRCS) in Allamakee County, says that although 24- to 48-row planters may be useful in central Iowa or other flat areas across Iowa, they don’t make as much sense in areas like northeast Iowa.

Rolling believes that a 12- or 16-row planter on steeper slopes is the maximum ─ with many slopes even too steep for these to help maintain conservation practices. “It takes about 60 feet to turn big equipment,” she said. “Grassed headlands (field borders) are now either gone or there is just a narrow strip of grass with 24 or 48 rows up and down the hill beside them.”

Rolling says farmers are also taking older terraces out altogether because 24-row planters and larger require about 60 feet per pass. She says many older terraces have about 90 feet of farmable space between them. “Larger planters can’t operate on older front slope lengths,” said Rolling. “Farmers are planting north-south or east-west because their equipment is too big to make those turns.”

Shut Off Sprayers Around Waterways
Jim Lahn, NRCS district conservationist in Plymouth County, says large farm equipment is becoming an excuse for not maintaining or even installing conservation practices. “On a daily basis, I hear farmers say they won’t install grassed waterways because the 90-foot or 120-foot spray booms almost always result in the herbicide killing the water way vegetation,” he said.

Lahn says farmers don’t necessarily need to downsize their spray booms to accommodate waterways. “If the farmer maps the waterway boundary using GPS, they can add that layer to the on-board computer data for the sprayer and the sprayer will automatically shut off over the grassed waterway, and not kill the vegetation,” he said.

Large equipment is also a problem for grassed waterways in northeast Iowa, says Rolling. “Our hills are very steep and often irregular with grassed waterways,” she said. “The larger equipment can’t maneuver to properly shut off at the waterway, so they are running up and down along the waterways, leaving tire tracks which wash all year long.”

Rhett Schildroth, senior product manager for Kinze Manufacturing, Inc., says waterways can easily be managed with auto-section control when planting. “Additionally, for farmers who plant the bulk of their fields with a 24-row planter, one option is to go back in with a 6- or 8-row planter to fill in the ends and corners,” he said. “This allows them to maximize both productivity and conservation.”

Is Big Machinery Efficient On Slopes?
NRCS Soil Conservationist Jacob Groth questions whether larger equipment is more efficient for farmers on hilly ground. “The time farmers spend maneuvering around obstacles, such as terraces, and turning to plant point rows decreases any efficiency gained with larger equipment,” he said.

Groth says there are farmers making smart management decisions, with conservation in mind. “Some producers are keeping a 12-row or smaller planter to plant fields not suited for their larger equipment,” he said. “Others are experimenting with different hitches for equipment and GPS configurations with auto steer to keep the planter between the rows on the contour.”

Larger equipment is to blame in some cases for farmers quitting no-till on steep slopes, choosing to till the soil because they slide down the slope enough to miss their target seedbed. “This sliding hurts the stand and ultimately the yield in no-till situations,” said Groth.

For more information about the benefits of conservation, visit your local NRCS office located at the USDA Service Center in your county.


Why are conservation practices important?
Since the Dust Bowl in the 1930s, farmers have been implementing conservation on their land to reduce soil erosion. Since then, many soil conservation practices have shown to improve soil health, which stabilizes the soil and aid in production. Conservation practices also improve water and air quality, promote biological diversity, and help attract wildlife.

Farmers using large equipment often struggle to navigate these conservation practices on hilly ground:

  • Contouring is preparing the soil, planting and cultivating crops around a hill rather than up down the hill. Crop rows run around the slope, nearly level. The rows form small dams to slow runoff.
  • Terraces reduce erosion by intercepting runoff on slopes, transforming a hillside into a series of shorter slopes.
  • Grassed waterways reduce gully erosion using grass channels to convey water to a stable outlet at a non-erosive velocity.
  • Field borders are bands of vegetation around perimeter of a field that provide a turning area for farm equipment. They eliminate the planting of end rows up and down hills.

To learn more about standards for these and other conservation practices, visit the Iowa NRCS website at and click on “Iowa Conservation Practice Standards.”