Managing rangeland with an eye to soil health was focus of several sessions during the recent 2019 Nebraska Grazing Conference in Kearney, Neb. Speakers discussed tools producers could use to assess rangeland health and then covered management techniques that could help diversify their grazing systems.
Patrick Shaver, who recently retired from the USDA’s Natural Resources Conservation Service (NRCS) and is now teaching in the Animal and Rangeland Sciences Department at Oregon State University, shared his experiences with the publication, “Interpreting Indicators of Rangeland Health.” He noted the booklet has undergone several updates since it was first released in 1994.
The publication was the result of an interagency committee established to incorporate the concepts and new science of the Nation’s Research Council (NRC) publication, which uses 17 indicators to assess rangeland health.
“The qualitative assessment is an assessment you can make on your land of what ecological processes work on your ground,” Shaver said. “The three main indicators of soil health are: Soil and site stability, hydrologic function and biotic integrity.”
Biological and physical components of an ecosystem will vary from site to site and over time, with disturbance a natural and necessary part of all ecosystems, he noted.
“Healthy systems generally resist disturbances and are resilient or able to recover from disturbances, but again these will vary over time,” he said.
By contrast, degraded systems are often highly resistant to change, Shaver added.
To show how the assessment works, he pointed to a case study of a gravelly site in Chihuahua Desert in Mexico. The site had nearly continuous grass cover, small bare gaps, low shrub density, no rills, pedestals or terracettes, high soil aggregate stability and was well developed. But disturbances such as overgrazing, a summer drought, water rills and a lack of fire caused an increase in bare ground, loss of soil surface horizon, adding to a low water holding capacity, meant there was no grass establishment.
“With no action the process of degradation means you may never recover from the losses,” he said.
Counteracting the increase in bare ground with grazing management factors of intensity, frequency and timing is one management technique that can reverse cover losses.
One thing all plants need is water, Shaver noted. Using the first letters to form an acronym, he discussed ways to manage water when it falls on rangeland.
“W — increase infiltration of the water,” Shaver began. “Air — we can manage air by increasing leaf surface to get more carbon dioxide. Temperature — we can insulate the plant crown to increase vegetation. Energy — sunlight we can increase leaf surface to enhance chlorophyll development. Raw materials — again we need to increase infiltration to access nutrients.”
Shaver noted there is a new version of “Interpreting Indicators of Rangeland Health” coming out next year.
“Version 4 was released in 2005 and Version 5 went to the printers last week for 2020,” he said.
Soil in the Sandhills
Dana Larsen, who recently retired from the NRCS and now works for her family’s ranch, Broken Heart Livestock at Thedford, Neb., shared her experiences during the session, “Managing a Sandhills ranch with an eye to soil health.”
“For the last 30 years I thought I was talking about soil health,” Larsen said. “One of the most significant things that came out of this is if we are talking about soil health, where do we put the thermometer?”
The Larsens have leased the Thedford area ranch since 2015 from the Dave and Loretta Hamilton family. The ranch covers Thomas and Cherry counties and includes 60 pastures, where the average size is a section. Together with her husband, two sons and interns, Larsen said they manage 1,100 mother cows and 350 yearlings.
Managing a ranch with an eye to soil health includes three points, Larsen said:
- Knowledge and understanding of the fundamental ecological processes of the grazing land
- Integrate soil health into goal-based, adaptive management after assessing and monitoring grazing lands to evaluate management action and climate influences
- Identify existing or build new partnerships on grazing lands soil health to enhance the technical capacities of students, land managers and natural resource professionals and practiced through laboratory networks.
“Drought is a big issue we deal with, as it can cause profound changes in soil health,” Larsen noted. “We have to refocus grazing management when that occurs. Sandhills soils are young. Soil samples are important, but shouldn’t be the sole basis for evaluation, it is also important to understand hydrologic cycles and other factors.”
She noted their lease requires documentation, and an inventory of their pastures was key to integrating soil health into goal-based, adaptive management.
“We know what our bare ground is and that it is less than 10 percent of our pastures,” Larsen explained. “One thing we do have are gullies and our goal is to reduce those. We also work to control invasive plants such as leafy spurge and Eastern red cedar. We carry loppers in our pickups and ATVs to attack the cedar wherever we see it.”
They also know they have good diversity in their grasses and Larsen noted they want to maintain the sand bluestem, prairie sand reed and needle grass plant communities where they currently exist. In addition, they discuss these goals and objectives regularly.
During the summertime, they try to reduce soil disturbance through the use of ATVs or horses. “If we can make a road disappear, we are reaching our goals,” she said. “The social aspects of management are also considered. We have gone back to roping at brandings.”
This has been a bit of a dilemma because they also want to have low-impact livestock handling, but the trade-offs so far have met their goals, she said.
“We manage with a light to moderate stocking rate and light to moderate utilization at about .45 AU (animal units) per acre,” she said. “Through this, we have about 42 percent utilization of the sand bluestem.”
Management also depends on proper record-keeping.
“We pour over grazing records, cattle body conditions and review those records,” Larsen explained. “We are now using a cell phone app for tracking much of this information.”
How in-depth have they gone?
“We are using 20 years of AUM (animal unit month) records, then also put the precipitation chart over that period,” she said, noting that is why there was a significant AUM drop in 2013 after the 2012 drought.
Good assessment and monitoring tools will help guide trending conditions, Larsen said. They use the Rangeland Health Assessment sheets from the NRCS.
“After a recent review we found lots of little bluestem, but noted we were short on some cool-season grasses that provide soil structure,” she said. “We are starting to use a VGS system — a vegetation geographic information data system. I am now using a tablet to capture data instead of clipboards and pencils” — something that has taken a while to get used to, she noted.
Do the principles of soil health apply to rangeland? According to Larsen, the answer is both yes and no.
“Some disturbance like fire is needed,” she said. “Then there are holistic and integrated approaches to soil health, which are the human dimension. Another way to improve soil health is using partnerships to enhance technical capacity. We experimented with a drone a couple of weeks ago, which holds some promise for improving those trailing and erosion spots around fences.”
Her conclusion for the conference attendees was to encourage them to know the fundamental ecological process of grazing land; integrate soil health into goal-based adaptive management; and use partnerships to enhance technical capacities.
Soil through the years
With soil health now a keystone concept in United States production systems, Virginia Jin with the USDA Agricultural Research Service, Agroecosystem Management Research in Lincoln, Neb., took a historical look at how this evolved.
Jin noted soil is the foundation of civilizations but can also lead to the fall of civilizations.
“When soils are degraded, either through the lack of knowledge or lack of will, disasters can happen,” she said pointing to the fall of ancient Greece, Rome and Egypt. “Plato wrote about the soil loss and impact on the landscape.”
Then there were the soil management failures in America during the 1930s, evidenced in photos not only from Nebraska, but also Alabama, Georgia and the Palouse region in Washington state.
“We had cattle who couldn’t find forage and an explosion of pest invasions like locust and jackrabbits,” she noted
Henry A. Wallace, then a student at Iowa State University, is credited with one of the earlier mentions of the importance of soil health in 1910 when he talked about using manure to build soil humus. Wallace went on to become a United States Secretary of Agriculture under President Roosevelt in 1933.
The 2018 Farm Bill includes cover crops, crop rotations and advanced grazing management as major conservation practices identified for improving agricultural soil health, Jin noted.
“What do these have in common?” she asked. “They increase plant species diversity and by increasing plant diversity, you increase habitat diversity such as soil microorganisms, pollinators and wildlife, decrease chemical controls and increase wildfire/drought recovery.”
The goal is to increase soil organic matter (SOM), which in turn improves soil physical properties such as soil bulk density and water infiltration. According to Jim, SOM also improves soil chemical properties with chemical nutrient density and improves soil biological properties, such as soil microbial biomass and crop productivity or yield.
While there are some benefits of soil health and management practices, Jin noted surveys have shown their effectiveness is highly variable. “It is clear that no single set of conservation practices are likely to produce the “silver-bullet” effect of improving all ecosystem function. Still it provides a useful framework to aid producers in making conservation management decisions,” she concluded.
Barb Bierman Batie can be reached at email@example.com.