By: Melisa Goss
How do farmers and ranchers make a living when they can’t predict how much rain is going to fall to grow their crops?
It’s a question Tanse Herrmann, State Rangeland Soil Health Specialist with the Natural Resources Conservation Service (NRCS), posed to a group of about 50 at the 2022 South Dakota Rural Women in Ag conference Oct. 7.
Drought is inevitable, but there are things that landowners can do to protect the health of their soil no matter the moisture level.
“I don’t care if it’s a backyard garden, in your yard, a 10,000 acre pasture, or a 1,000 acre field. If we’re going to enhance or even simply maintain soil health and function, we have to follow these five basic principles,” the self-proclaimed “soil health geek,” stated.
The five steps are: armor the soil, minimize disturbance, enhance diversity, incorporate living roots and introduce livestock.
Armor the soil
While sun and rain are vital for plants to grow, too much of a good thing can be damaging.
Protecting the soil from the impacts of the intensity of the sun and impact of a raindrop is important for keeping it healthy. As a general rule, soil should be covered whenever possible. You can plant cover crops as part of both grazing and cropland operations. Plant cover crops, use organic mulch and leave plant residue on the ground.
This particularly comes into play in the heat of the summer. Soil, just like humans, starts to get uncomfortable when the mercury climbs over a certain threshold.
“As we hit 95, all of us begin to feel uncomfortable. I start to sweat, start to look for shade and something to drink. Soil biology and plant roots are much the same way,” Herrmann said.
When soil temperatures reach 100 degrees, vital microbes begin to die. While some of them can dig themselves deeper into cooler soil, many of them are not able to be mobile and won’t survive the heat.
Soil temps can reach up to 120 to 130 degrees on a hot July or August day.
Residue or shade from a canopy can go a long way to keep the soil temperatures down and the microbes happy and healthy.
While some disturbance is unavoidable, minimizing disturbance events such as tilling and over grazing builds healthier soils.
Tillage is the primary culprit when it comes to disturbance, to the point that Herrmann encouraged landowners to “stop the bleeding,” meaning tilling essentially bleeds the soil dry of key microbes and nutrients.
A rototiller, disc or chisel fractures earthworm tunnels and root channels, which increases what’s called “bulk density.” Increased bulk density means the water spaces in the soil have decreased in size.
This can lead to what Herrmann referred to as a worst-case scenario where the soil has a flour-like consistency, and water cannot easily penetrate the soil, leading to run off.
Discussing grazing, Herrmann paused and rephrased the topic at hand saying “optimize disturbance” might be a better turn of phrase. Grazing is technically disturbing the soil, but it is also important for soil health.
Timely rotation is key to ensure the ground is neither undergrazed nor overgrazed.
“If you can see the cow turds, you’ve overgrazed,” Herrmann said.
Enhance diversity, incorporate living roots
Adding diversity can break disease cycles, stimulate plant growth, and provide habitat for pollinators and organisms living in the soil. Simple ways to boost diversity is to plant diverse cover crops, utilize a variety of crop rotations and integrate livestock.
Herrmann also encouraged incorporating living roots for as much of the year as possible.
The most biologically active part of the soil is right next to plant roots. Living roots reduce soil erosion and provide food for organisms like earthworms and microbes that cycle the nutrients that plants need.
“We have to have plants in order to have active soil biology,” he said.
Reducing fallow, planting cover crops and diversifying crop rotations are all beneficial.
Some of the native plants found in South Dakota have root systems that extend 15 or 20 feet deep. These roots provide a pathway for water and nutrients to flow up and down the soil profile.
Herrmann said about half of a plant’s roots slough off every year, dying and then regrowing the following season. The portions of the root systems that die become a pipeline for water into the soil.
Likewise, maintaining adequate rest periods between grazing rotations is important in order to let the roots replenish themselves underground.
“So, these types of plants in the landscape along with diversity are incredibly important for our agricultural systems here,” Herrmann said.
Whether considering crop land or gardens, incorporating livestock is crucial to soil health.
The term livestock can be used fairly loosely, Herrmann said.
“Livestock can be honeybees. It can be poultry. It can be llamas or camels, I don’t care,” he said. “We need to recycle plant materials through the body of an animal to enhance the natural processes that break down plant materials into something that is more available for fertility.”
Herrmann noted that many South Dakotans raise cattle.
“Get those cattle out there. They’ve got four feet. Let them work,” he said.
However, maintaining stocking rates is also important. Herrmann likened it to a checking account, stating that withdrawals can’t exceed deposits. He encouraged adaptive management, meaning plants are ready to be grazed for the appropriate amount of time at the correct degree of utilization along with a long recovery period.
Herrmann said that grazing between 40 and 50% leaves enough above ground material to aid root growth. Essentially, the plants will keep growing roots while recovering from the grazing because there is ample green leafing that will continue to capture sunlight and photosynthesize.
Grazing over 50% can lead the plants to stop growing roots.
Grazing is not only beneficial to the soil, but is also beneficial for livestock. Fall and winter grazing of cover crops and crop residue can boost livestock’s nutritional intake. Cattle instinctively know what they want and need. They will automatically choose to graze on the plants that will meet those needs.
Herrmann said he understands that changing operational modes can be daunting. However, a few key components of incorporating soil health practices is to be committed, be patient and be an observer, he said.
Change is not going to happen overnight, and producers don’t have to feel alone.
South Dakota has a very diverse landscape with over 800 different types of soil, according to the South Dakota Soil Health Coalition.
That’s why the South Dakota Conservation Mentor Network was organized. The network connects producers who help each other by sharing their experiences. Mentors will help guide producers through their specific management questions and needs.
The service is free and is available to anyone. To get connected, interested parties should contact their local NRCS representative, the South Dakota Grassland Coalition (SDGC) or the South Dakota Soil Health Coalition (SDSHC).