Westover: Soil health management mimics management of cattle rumen
With much overlap in the realm of ranching and farming, Montana State University Extension Educator Elin Westover notes that, while many ranchers are farmers and vice versa, producers do not see themselves as experts in both aspects of their operation.
“Similarities in the biological systems of each field mean similar approaches can be used to maximize production in soils and livestock,” Westover says. “Soil functions as a plant’s stomach, similar to the role of the rumen in cattle and sheep.”
Westover further explains that microorganisms, including bacteria, fungi and protozoa, populate both systems, and the health of the system depends on the health of the microorganisms.
“Health and productivity of rangeland and crops, as well as cattle and sheep, can be attained by feeding and managing microorganisms and their environment,” she says.
Who eats first?
In obtaining healthy systems, Westover says, “Rumen microorganisms must eat first, which, in turn, will feed the animal.”
When feed enters the rumen, she explains that microorganisms break it down into useable nutrients, which are then used as energy for the animal.
“For example, rumen microorganisms break down carbohydrates for their use, and volatile fatty acids are an end product,” she says. “In turn, volatile fatty acids are used as an energy source for the host animal.”
As in the rumen, microorganisms in the soil break down material before plants can access the energy available.
“Organic forms of nutrients, such as nitrogen, phosphorus and sulfur are present in the soil, either as crop residues or manure, and must undergo a mineralization process before the nutrients become plant-available,” Westover notes.
Messing with bugs
In the rumen, contents are partitioned based on their density, and specific microorganisms are associated with each layer.
“If rumen contents were vigorously stirred into one homogenous mixture, the animal would not perform normally,” says Westover. “The microorganisms’ environment would be completely disturbed, and it would take time for their environment to be re-established.”
Similarly, soils operate in the same way.
“Management tools, such as tillage, fertilizer and pesticide application and livestock, can be used to improve soil productivity and can be detrimental to soil health if not practiced correctly,” she emphasized.
Improper use of management tools can disrupt soil microbes and force them to readjust to establish a new equilibrium.
“For example, in the short term, tillage helps microorganisms break down organic matter, but in the long term, this loss of organic matter will hurt soil health and crop yield,” Westover says.
In the same idea, Westover notes that because microorganisms require time to adjust to new environments, diet changes should occur slowly – over a period of roughly seven days.
“Livestock producers are encouraged to change rations gradually, by introducing a new roughage or concentrate sources to livestock incrementally,” she comments.
Slow, incremental introduction of new feeds allow bacteria, fungi and protozoa to adapt to the new foods.
Westover continues, “Likewise, change in soil quality and health will not improve overnight. Time is required for microorganism populations to build to a beneficial level.”
When looking at ruminant and soil health, a proper balance of nutrients is essential, particularly carbon and nitrogen.
“The ‘bugs’ use the nitrogen and carbon from protein to grow, and their waste provides a portion of the essential amino acids the animal needs,” explains Westover. “If there is a shortage of carbon, nitrogen cannot be utilized and is excreted by the animal.”
At the same time, nitrogen deficiencies result in reduced microorganism activity.
“The carbon to nitrogen ratio is critical in balancing the breakdown of organic matter in a slow-release fashion,” she says. “If the ratio is too high, organic matter is degraded too slowly, and the nutrients do not cycle quickly enough between the soil, plant and microbes.”
An excess of organic matter can also result in lack of nitrogen availability to plants.
A low ratio of carbon to nitrogen means that nutrients cycle too quickly and plants do not have access to essential nutrients. Soil oxygen may also be depleted.
“Additionally, when degradation of organic matter is occurring too quickly, soil becomes vulnerable to wind and water erosion, and there is increased evaporation,” she says.
When looking at managing both cattle and soil, Westover comments that producers can utilize a similar scientific foundation.
“Managing the soil as microbial habitat is critical to the functioning capacity of the soil, just as managing the rumen as microbial habitat is critical to the health of a cow or sheep.”
This is part one of a two-part article. In the second part, Westover looks at creating the ideal environment, establishing diversity and looking at the biology of organisms to manage soils.