Get the dirt on soil.

As we honor World Soil Day 2020 on December 5, we must continue efforts to keep soil alive by protecting its biodiversity because healthy soil is the very foundation of productive, sustainable agriculture.

You may think of farming as crops that grow above the ground, but none of that happens without what goes on below…in the soil itself. This life-sustaining substance is so much more than just dirt.

Healthy Soils = Healthy Planet

Soil is where farmers start and end their crop cycles. Without proper care to maintain healthy, fertile soils, the land will no longer be able to produce crops, and our entire existence on this planet is at risk. Soil that’s alive and healthy can keep us alive and healthy!

As our global population continues to grow, our farmers are asked to produce more from every acre of land, and do so in a cost-effective way that ensures a safe, affordable food supply. To achieve higher yields every year, they must be scientists and soil doctors who truly understand and respect what’s under their boots and the tires of their farm equipment.

 

Life Underground

Without getting too deep into the science of dirt, soil organic matter contains both living micro-organisms and dead components of fresh residue and humus, per the Ohio State University Extension.

According to the Food and Agriculture Organization of the United Nations (FAO), soil biodiversity relies on an entire underground community to feed and protect plants. In the past year, we shared some of this information about the necessary work of worms, beetles, microscopic bacteria and fungi found in healthy soil.

Organic matter acts like a sponge to hold more water. Every 1% increase in organic matter results in as much as 25,000 gallons of water-holding capacity per acre (NRCS).

Well-maintained soil can more-easily endure the extremes of volatile weather from flooding to drought. Healthy soil forms clumps of granules called aggregates that help prevent erosion and improve water infiltration instead of run-off.

The end goal is to prevent the release of carbon from the soil, which happens when the ground is tilled. Unfortunately, the more carbon that’s added to the atmosphere causes climate concerns that affect us all.

 

 

Soil Healthcare

When it comes to soil healthcare, most management practices fall into three categories: what’s on top of the ground, what’s in the ground, and what you do to the ground.

The crops that are planted in the soil can build, maintain, or reduce organic matter. Rotating between crops, such as planting corn one year then soybeans the next, is also helpful for biodiversity.

After harvest, some farmers choose to plant high-carbon cover crops that can actually feed the soil more carbon, while cover crop roots provide a continual food source for microbes. Farmers can also add livestock to graze those cover crops, saving on other costs for feed and fertilizer.

One of the more obvious soil healthcare concepts is to reduce soil disturbance by choosing no-till or reduced-till farming practices. Instead of using plows and disks to turn over the entire field’s soil, farmers can plant seed into a narrow slot without moving much soil. In fact, they can even seed right into existing crop residue.

This goes hand-in-hand with another key concept of leaving more residue or “cover” on top of the surface to help prevent topsoil erosion, catch snow for moisture, and reduce surface run-off.

Regenerative Agriculture

“Regenerative Agriculture” describes farming and grazing practices that, among other benefits, reverse climate change by rebuilding soil organic matter and restoring degraded soil biodiversity – resulting in both carbon drawdown and improving the water cycle. (RegenerationInternational.org)

American Farmland Trust’s research shows that adoption of cover crops and no-till as regeneration practices on 70% of America’s cropland is equivalent to removing 53 million cars from the road.

Thankfully, South Dakota farmers now choose no-till practices on over 50% of their total acres, and more than 900,000 acres of cover crops were planted in this state last year (NRCS 2019). According to the 2019 CSI, 20 counties, mostly in the central part of the state, have more than 75% of their cropland under no-till systems.

Stewards of the Land

By managing for optimal soil health, farmers can partner with the land – not against it – to minimize erosion and run-off, maximize water infiltration, improve fertility, save money on costly inputs, and ultimately, improve the livelihood of their land.

To grow a corn crop in South Dakota, farmers have to manage many aspects from weather to water, as well as weeds, disease, and pests that threaten their crop yields. The soil is another major factor they must manage to succeed.

Having a healthy soil isn’t just for the sake of this season’s yields though. Sustainability through soil health is a long-term solution for profitability. Achieving and maintaining healthy soils are necessary to ensure future generations can continue to benefit from the soil’s ability to produce a crop.

 

 

As a closing thought to mark World Soil Day 2020: “Soil health is difficult to build, hard to maintain and easy to destroy,” shares Dan Forgey (shown at right) of Cronin Farms in Gettysburg, a long-time soil-health advocate, 2016 Leopold Award winner, 2017 SD Corn Excellence in Ag award winner, and no-till farmer since 1993. Forgey was a featured speaker at the Fall 2020 National Cover Crop Summit.

To learn more about soil health and World Soil Day, visit the United Nations’ website.

  • 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.