Farming for Sustainability: Understanding Tillage

Have you ever seen a vintage photo or illustration of a farmer laboring in the field with an ox-drawn plow? It would take a farmer with one ox about one day to plow a single acre!

Fortunately, farm equipment has progressed—as have farming practices. Today’s farmers use a variety of tillage implements and strategies, depending on their specific situation.

Brad Ruden, agronomy tech services manager at Agtegra Cooperative says, “Growers are trying to get the most productivity they can out of their soils. It may mean no-till in some areas. It may mean focused tillage or full tillage in others.”

Today, farmers most often use implements such as field cultivators, discs or vertical tillage implements. This type of equipment shifts the top layers of the soil but doesn’t disturb the soil structure below.

Why till?

In the past, tillage was used to bury weeds and create a smooth, black seedbed in preparation for planting. “With our current technologies we can easily plant in a no-till situation,” Ruden says.

Tillage plays a significant role in certain areas of the state. While South Dakota farmers have traditionally focused on keeping moisture in the soil, those in the southeastern part of the state can be challenged with too much moisture—especially in years like this one.

“Farmers today use tillage to break down the crop residue that’s left in the field from the previous season, and cycle it back into the soil,” Ruden says. “Sometimes residue can be negative because it can keep soils very, very cold in the spring.”

Ruden explains that tillage does help dry out the soil, but not without risk. “Tillage would be desirable to help these soils to warm up. But it’s easy to compact soils with heavy equipment, and that’s more likely to happen when soils are wet.”

Why no-till?

According to Ruden, the most common tillage production practice in South Dakota is no-till.

After harvest, farmers simply leave the cornstalks or soybean plants in the field to decompose. This builds the soil’s organic matter and nutrients.

No-till also maximizes the soil’s ability to absorb water.

“In much of our state, water management really is the critical limiting factor in crop production,” says Ruden. “It’s the fact that we just simply can’t get enough moisture to these plants, regardless of anything else we do, to be able to maximize our yield potential.”

Some of the tillage practices of the past actually harmed the soil. “We never really understood soil structure well enough to know what all those aggressive tillage methods like plowing did to our soil structure,” Ruden says.

“More recently, we’ve realized that we were creating what we would call a tillage layer in that field, where we were compacting a layer of soil at the bottom of that plow level. So then we would create a very, very dense layer of soil in there. Our crops’ roots simply couldn’t penetrate through that.”

Farmers don’t want to restrict root growth. “That’s where the no tillage situation came in. But then we have to manage the things we’re creating as well, like residue,” says Ruden.

Why strip-till?

Fortunately, tillage isn’t an all-or-nothing farming practice. There’s an entire spectrum of options, including minimum or conservation tillage and focused tillage.

“We also do strip-tillage in some areas,” Ruden says. “We apply fertilizer in a very narrow band. And then we’re tilling that band of soil in the fall of the year to allow that particular soil to be able to warm up in the spring and provide us a nice planting bed.”

With strip-till, farmers still realize many of the benefits of no-till. The rest of the field cycles residue and absorbs moisture.

Focused tillage is another option. According to Ruden, farmers will till specific areas for weed control when other weed management strategies aren’t working.

Striking a balance

Tillage works hand-in-hand with other farming practices, such as crop rotation, cover crops and focusing on soil health.

Many farmers adjust these practices from one year to another to maximize sustainability and productivity.

“Finding the right balance is part of the art of agriculture,” says Ruden. “And that’s why having that partnership between a grower and an agronomist and finding the right balance of things to do on that farm is so important.”

“But I think our growers do it better than anybody in the world,” he adds. “That’s what we’re all about.”

If you have questions about farming practices, please contact South Dakota Corn at 605-334-0100.

Tillage video footage provided by Great Plains Manufacturing.

  • Twenty years ago, U.S. farmers were feeding an average of 85 people each. Today that number has jumped to 155.
  • Over the last 20 years, U.S. corn production grew 80 percent, while:
    • Land use decreased by 37 percent.
    • Soil loss decreased by 69 percent.
    • Energy use decreased by 37 percent.
    • Emissions per bushel decreased 30 percent.
  • Growers raise 70 percent more corn per pound of fertilizer than 35 years ago.
  • Farmers today grow five times more corn than they did in the 1930s.
  • The average yield per acre has grown from 24 bushels in 1931 to 164 today. Contest winners have averaged over 600 bushels per acre.
  • Reduced tillage prevents erosion. Its adoption in South Dakota has increased from less than five percent in 1985 to 35 percent in 2010.
  • One acre of corn removes eight tons of greenhouse gases.
  • Thanks to ongoing innovations in seed, equipment and fertilizer technology, the amount of emissions per bushel generated to produce corn fell 30 percent in the last 20 years.
  • Farmers use Global Positioning System (GPS) technology to guide equipment so overlapping doesn’t occur.

Scientists have proven that corn grown in South Dakota actually adds carbon to the soil by virtue of the unique Northern Plains climate and increased use of minimum tillage practices by farmers.

  • Over the 25 years of the study, South Dakota corn average yields have increased at a rate of 2.29 bushels per acre per year.
  • Higher yields mean more crop residue left behind. The increased amount of residue has a significant impact in building soil carbon.
  • Our cooler Northern Plains climate plays a key role in the equation due to mineralization, a process by which organic matter and humus break down in the soil. When there are cooler temperatures, the mineralization rates are lower.
  • No-tillage adoption in South Dakota has increased from less than five percent in 1985 to 35 percent in 2010. Minimum and no-tillage production means there is more residue left behind in cornfields. Those practices also mean fewer trips across a field, resulting in even greater environmental benefits.

South Dakota farmers are protecting natural resources.

  • Advances in seed science, machinery and precision farming tools help farmers grow more with simplified weed control and reduced chemical applications.
  • One acre of corn removes eight tons of harmful greenhouse gas, more than what is produced by your car annually.
  • Because of innovative fertilizer application methods and frequent soil testing, American farmers grow 87 percent more corn per ounce of fertilizer.
  • Planting cover crops and/or moving to longer crop rotations allows farmers to naturally manage soil fertility, quality, water, weeds and pests – and improve farm habitat for wildlife.

Reduced tillage conserves soil.

  • Reduced or no-till planting conserves soil and water and reduces soil erosion and fuel usage.
  • No-tillage adoption in South Dakota has increased from less than five percent in 1985 to 35 percent in 2010.
  • Reduced tillage and other farm management practices have decreased soil erosion by 37 percent in 20 years.

South Dakota farmers protect water quality.

  • Farmers work hard to protect streams, ponds, rivers, lakes and wetlands. By keeping water edges in their natural state, we help control runoff and erosion and allow water insects, animals and fish to thrive.
  • Cover cropping helps reduce soil erosion.
  • Natural vegetation “filter strips” intercept and trap pollutants and soil from fields before they reach waterways.
  • Furrow alignment reduces the amount of runoff from rain or irrigation.
  • Diversion channels send runoff to safe areas and prevent excessive erosion.
  • Buffer strips and grass waterways in ditches capture sediments or nutrients and prevent erosion.

Drain tiling in a field is similar to drainage around your home — diverting water where it is not wanted. It’s a way to manage excess water and to keep nutrients in the fields. Tiling helps with:

  • Reducing storm water runoff and downstream flooding through absorption.
  • Reducing water damage to public roads.
  • Decreasing crop loss due to drowning.
  • Increasing soil surface temperatures, which helps seeds germinate.
  • Allowing plant roots to grow deeper into the soil so they can absorb more nutrients.
  • Providing enough oxygen for plant roots to mature properly.
  • Increasing the number of days available for planting and harvesting crops.
  • Improving soil structure by avoiding soil compaction and structural damage.
  • Promoting energy-conserving farming practices such as no-till and conservation tillage.
  • Reducing loss of sediment and nutrients.
  • Allowing for more efficient use of resources.