All life on earth is either contained in or springs forth from the soil. In natural systems, when water is available and sunlight shines on photosynthetic green leaves, the soil and the air provide all else that is required for plant growth.
The vast American prairie evolved and adapted to the presence of large herds of grazing animals that stayed closely bunched. These herds moved about freely when influenced by predation, weather, food, water and the urge to get away from their own fouling of the ground with manure and urine and the subsequent fly hatch that was going to occur.
These large animals were accompanied by smaller animals that may also have grazed but did so differently; they tended to be nibblers and browsers. Other creatures in the ecosystem included the vultures and scavengers, along with birds and insects, all of which had a role in maintaining healthy soil and vigorous plant growth.
In that situation, the prairie soils had high organic matter. When farmers plowed and uncovered the soil, the organic matter dropped to a fraction of what it used to be. When ranchers began to enclose and graze their domestic livestock in pastures or ranges continuously or in the same season each year, organic matter also diminished – perhaps not as much as with farming – but there was still a loss of soil health and vitality. We’ve all heard the pioneers’ stories of stirrup-high grass being grazed by millions of bison.
Today’s farmers are abandoning their old tillage methods in favor of strip-till, ridge-till and no-till. These changes were instituted initially as a way to reduce machine usage and save money, but farmers came to realize that the soil quality is improved when crop residues are left on the land to act as cover and to gradually return to the soil by natural biological processes.
Animals may graze some of the residue, and leave manure and urine as they do. As they graze, the animals also trample some of the old plant material into the soil, which speeds the decaying process to further enrich the soil.
Birds may pick through the manure to get bugs, worms and other nutrients, and then leave their own droppings, which become food for something else. Little creatures from the soil (and there are many) emerge to eat their share of the crop residues and the animal droppings, doing their part to move nutrients back to the soil.
Some of the soil microbes get nourishment from the roots of plants and, in exchange, nourish the plants. Creatures are reproducing and dying all the time, and the dead become food for other creatures or the plants. The complexity is amazing and not totally comprehensible.
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By our presence, humans, farming and domestic livestock have assumed a role in what the soil becomes. We can influence biological and ecological processes – which really tie together as one process – to degrade, maintain or improve the health and productivity of the soil.
Mother Nature hates monocultures and bare ground. That’s why weeds will invade any area of bare soil, whether it is degraded rangeland or the bare ground between rows of farm crops. In a balanced healthy ecosystem, there is much biodiversity; and whenever there is moisture, sunlight and appropriate temperature, new green plant material is growing while old decaying plant material is being returned to the soil.
Many farmers and ranchers are learning that the most important thing they can do for the soil is to keep it covered. By doing this, wind and water erosion are greatly reduced, water infiltration is improved, as is water-holding capacity; and those improvements continue to build if we keep the soil covered. In addition, soil temperature is less variable – it doesn’t get as hot in the summer or as cold in the winter. This produces a micro-climate conducive to soil microbial activity and new seedling survivability. Plus, evaporation is reduced.
That’s why you hear and read more today about mob grazing. The basic idea in mob grazing is for the animals to graze a third to half of the forage, trample another third to two-thirds, and leave a small standing residual with long rest periods between grazing exposures. The trampled portion, plus the manure and urine deposited on the soil by the grazing animals, feeds the soil and speeds up the mineral cycle.
The practice of the various forms of high-intensity, low-frequency grazing varies widely to fit the circumstances. Some farmers lengthen their crop rotations by adding cover crops to always keep the soil covered, and reduce and reverse soil compaction. Others utilize livestock to graze crop residues and cover crops; and some even add a full year of grazable cover crops to their rotation. Still others are adding 2-4 years of alfalfa or pasture in the rotation.
Many of the farmers who integrate livestock into their farming operations feel the practice brings back some of the important influences under which the soils originally evolved and developed. There are many relatively new ideas being tried with the object of utilizing water more efficiently, cut machine and fuel cost and, most importantly, improve the soil.
As ranchers, we spend our lifetime focused on the animals or the crops that we harvest to feed those animals. I’ll admit that for many years I paid much more attention to animals and crops, and their immediate performance and yield, than anything else. Thanks to some excellent teachers and mentors, along with good farmers and ranchers I know, I came to understand that taking care of the soil must come first if we want to be truly sustainable – economically, ecologically and socially. Then, yes, we can and should pay attention to the crops and the animals; and, with an ever-improving soil, they will yield a bigger harvest.
Burke Teichert, consultant on strategic planning for ranches, is retired as vice president and general manager of Deseret. He can be reached at [email protected]
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