When I’m walking in a field with a strip-tiller, we’ll invariably talk about visual indicators that reflect benefits of the practice — increased earthworm populations, mellower soils and better soil texture.
But what is actually going on beneath the soil surface?
This is something veteran strip-tillers Rod and Rick Sommerfield have evaluated since moving from conventional-tillage practices to strip-tilled corn and no-tilled soybeans on their 500-acre operation near Mazeppa, Minn., 14 years ago.
They view conservation tillage as a natural management tool to transition from improving soil tilth through tillage to improving tilth through nature.
“One of our goals is to help farmers understand how we can move beyond conservation agriculture to regenerative agriculture,” Rod says.
In 2012, they started a group known as “Soil Organic Matter Generators” to help farmers embrace the transitional benefits moving from conventional tillage to strip-till and no-till can have on soil health and structure.
As the Sommerfields acknowledge on their website, tillage has addicted productive soils to the need for more tillage to provide space in the soil for air and water to move. Their philosophy is that nature has, and can create, the same space in a more environmentally friendly way.
The key to long-term sustainability, the Sommerfields say, is having bio-diverse, healthy, living soils. This requires farming in way that can generate new soil organic matter.
To test progress on their own farm, they conducted a water infiltration test in spring 2014. The goal of the experiment was to observe how soils with high organic matter resist going into suspension when flooded with water.
The fall prior, they filled a terrarium with soil from a field in a 13-year no-till soybean/strip-till corn rotation. The slope of the field was about 9% and soil tests revealed an increase in organic matter of 2% since 2000.
The terrarium temperature was stabilized at 50 degrees throughout the winter and during that time, visible changes to the soil included worms feeding on a dried hairy vetch cover crop. That helped double the depth of the high-organic matter horizon from 1-2 inches and also increased the topsoil horizon several inches.
“When we poured about 4 gallons of water on top to simulate a heavy rainfall, it filtered through the bottom within a couple minutes and was clear enough to drink,” Rod says. “We didn’t have any runoff, so we know that soil is naturally letting water or nutrients work its way through.”
To hear more from Rod Sommerfield, join us at the 2015 National Strip-Tillage Conference in Iowa City, Iowa, where he will discuss the concept of regenerative agriculture and how this process can help make healthy soils less susceptible to weather extremes.