COLUMBUS, Ohio -- As Ohio farmers harvest their corn and soybeans during what is turning out to be the wettest fall in at least three years, they are being encouraged to keep in mind the one thing that could negatively impact next year's crops: soil compaction.
Randall Reeder, an Ohio State University Extension agricultural engineer, said that heavy farm equipment, such as tractors, combines and grain carts, driven on wet or saturated soils increases the risk for soil compaction. Compaction destroys the soil structure and leaves ruts, increasing spring planting problems and potentially contributing to poor plant performance.
"Compacted soils reduce root growth, making it harder for roots to reach deep into the soil. They also reduce the ability for rainfall to penetrate the soil," said Reeder, who also holds a partial research appointment with the Ohio Agricultural Research and Development Center. "A compacted surface layer often seals off any chance of water being absorbed into the soil, and it just moves as run-off, causing erosion."
Not only does soil compaction prevent a fruitful spring planting, but it also affects plant performance and impacts yields.
Sixteen years of Ohio State research on Hoytville silty clay loam showed that through compaction from a 20-ton per axle load, at least 10 percent of potential crop yield was being left in the field, adding up to thousands of dollars in lost profits for large-farm growers.
Growers can help minimize some of the issues surrounding compacted soils with the following tips to help reduce compaction during harvest:
• Run tires at the correct pressure for the load. "Many farm tires are overinflated, which reduces the tire footprint, increasing compaction," said Reeder. "Many farmers can easily reduce tire pressure and it won't cost them anything." Over-inflation also reduces traction.
• Remove excess weights that make machinery heavier than it has to be.
• Practice controlled traffic, a method whereby all farm equipment is the same width and traffic is confined to specific paths year after year. "Wet soils show the value of the system, and with auto-steering systems more available today, the opportunities for controlled traffic are much greater than they were a few years ago," said Reeder. "Auto steering systems also make it easier for farmers to make the transition into continuous no-till."
• Use continuous no-till, with strip-till for corn. "Farmers till the ground to break up compacted soil, but if they are in a controlled traffic situation, harmful compaction is minimized, so there is no need for tillage," said Reeder. Continuous no-till provides a myriad of benefits in crop production from improved soil quality, to reduced soil erosion, to increased yields. "No-till soils have a more solid structure than tilled soils. Good no-till soils create their own natural channels for root growth and water permeation, from old root systems to earthworm burrows," said Reeder.
• Don't fill the grain cart to capacity. "The grain cart is usually the heaviest piece of equipment in the field, followed by the combine and tractors," said Reeder. On wet soils, try to empty the cart more often so it's never more than about half full. Where possible, keep the cart at the end of the field.
• Try to empty the combine before the grain tank is full.
• Add more tires, or switch to bigger tires or rubber tracks. The more rubber that comes into contact with the ground, the less pressure on the soil.
• Consider improving surface and subsurface drainage. A good drainage system helps the soil dry out faster, reducing the potential for soil compaction.
"Some of these practices may slow down a farmer during harvest, but they are good points to keep in mind that could lead to better soil structure and minimize any damage to next year's yields," said Reeder.