Utilizing cover crops helps growers accomplish the five principles of soil health

Published on April 4, 2020

“The five principles of soil health are a combination of ideas on how to keep soil healthy,” states Natural Resources Conservation Service Rangeland Health Specialist Ethan Walker, during the March 27 episode of Kansas State University’s Agriculture Today podcast. 

            Walker then points out cover crops can make a contribution to each of these five principles. 

Soil armor

            “The first principle is soil armor,” says Walker. “Soils have residues which act as armor and are important for regulating soil temperature and battling erosion. Just like we have skin, soil has residue to protect it.” 

            In addition to minimizing erosion and managing soil temperature, soil residue also decreases plant pressure, according to Walker. 

            “If growers don’t have enough residue, they might add a cover crop to reduce the next year’s weed pressure,” he says.

            When considering cover crops to increase soil armor, Walker says growers need to be specific about their cover crop selection. 

            “It all comes down to the carbon-nitrogen (C:N) ratio,” he says. “If a grower wants a longer-lasting residue, they want to pick a cover crop with a higher C:N ratio so it takes longer to break down.” 

            Walker notes in this situation, growers should choose cereal rye or oats as their cover crop. They should not choose legumes or clovers because they have a low C:N ratio. 

Minimizing soil disturbance

            According to Walker, the second principle of soil health is minimizing soil disturbance. 

            “This isn’t just a physical disturbance such as tillage. It is also biological and chemical disturbances as well,” Walker says. “We can actually disrupt our soil ecosystems by adding too many chemicals such as fertilizer or pesticide.”

            However, Walker notes cover crops can help growers minimize soil disturbances.

            “It all comes back to our soil armor and reducing weed pressure,” he explains. “If we are adding soil residue and lowering weed pressure by utilizing cover crops, we will have lower chemical costs and less need to till, which will save us money in the long run.” 

Plant diversity

            The third principle of soil health Walker lists is plant diversity.

            He explains a monoculture crop rotation will typically result in a monoculture soil ecosystem, which may result in pest pressure, especially from nematodes. 

            “By adding diversity to our crop rotation, we get a diverse compound excreted from the cover crops we use, which invites other hosts and predators and controls the predator-prey relationship in the soil. This can control nematode and other pest problems,” Walker says. 

            “This doesn’t mean growers should add a single cover crop. They should have a grass-hay, legume and brassica cover crop in their rotation, at least,” he adds. 

            As an example Walker points out a typical corn-bean rotation has very little diversity.

            “Obviously, adding winter wheat into the rotation helps with the diversity, which most producers do,” he says. “But maybe they should switch it up a little and throw in a summer crop like sunflowers or canola. Mixing up the rotation is very beneficial.” 

Continual live plant root interaction

            According to Walker, the fourth principle of soil health is continual live plant root interaction, which he notes has a lot to do with carbon movement in the soil. 

            “We have to feed all of the microbiology in our soil, and carbon is their main food source,” Walker explains. “If we have a field in fallow, those organisms aren’t getting food, and they have the potential to die out. By adding a root system for those organisms to feed on carbon, we keep our soil ecosystem functioning.”

            Walker notes cover crops are incredibly important for this principle.

            “Substituting cover crops for a dormant rotation is really beneficial,” he states. “Instead of having a fallow period in between crops where a lot of the microbiology in the ground will slow or stop completely, cover crops provide continuous live plant root interactions to feed our soil ecosystems.” 

Livestock integration

            The fifth and final principle of soil health is to integrate livestock, according to Walker. 

            “First and foremost, this is a good economical decision for our pocketbooks, because while our field is fallow, we can get some extra income by grazing a cover crop,” he says. 

            Walker also notes integrating livestock improves the nutrient cycle because as livestock graze the cover crop, they recycle the nutrients back into the ground.  He explains these nutrients are also more readily available for plants to utilize. 

A good recipe

            “By putting all of these principles together and utilizing cover crops, we have a good recipe to improve soil health,” states Walker. 

            He continues, “By using this recipe, inputs will start to decrease, yields will potentially increase and growers will see an increase in profitability due to lower input costs.” 

            Hannah Bugas is the assistant editor for the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.