Farmers, ranchers taking after bison when it comes to keeping soil healthy
April 6, 2017
The bison may be long gone from the prairies, but their grazing habits are being replicated on ranches across the Great Plains.
When millions of bison moved from place to place, their grazing habits forced plant life on the prairies to grow and thrive.
And now that the buffalo are gone, ranchers and farmers are copying their habits.
It's all in the name of soil health, and if the soil is healthy, there's a good chance the pastures, meadows and fields are healthy.
Ranchers and farmers can do a variety of things to improve the health of their soil, said Dave Olilla, South Dakota sheep extension field specialist and rancher from Newell, S.D.
Grazing is a good place to start. The old rule, Olilla said, is "you graze half the forage and leave half of it." Grazing forces the plant to grow more roots, which leaves a stronger, healthier plant. "Those prairie plants evolved with a grazing animal on top of them," Olilla said. "They respond and do better if they're grazed. Not overgrazed, but grazed."
There are a number of ways to take half the forage production and leave half, Olilla said, but the most common is "once-through" grazing: cattle or sheep graze an area till it's half-gone, then they are moved off that pasture. That grass is then given a "rest" time. After you've taken off half, you never go back to it that year, Olilla said.
"It rests for the rest of the year," he said.
"What we're trying to do is emulate the migration of the buffalo," he said.
The animals would graze an area intensely then move on, not to return for months, or even until the next year.
Depending on a rancher's resources and time, some producers fence off an area, graze it intensely, then move cattle or sheep to the next area. That's not a common practice where ranchers have a couple-thousand acres of grass, but it works for those producers who have the time and resources for fencing and herding, Olilla said.
Many of the plants west of the Missouri in S.D. are cool season plants, including the three common ones: green needle grass, western wheatgrass, and sedges, and they make an appearance in early spring, so once-through grazing works well in West River. "Most of our production is determined by the middle of June," Olilla said. "We know what we have for grazing forage material for the rest of the year, based on what has grown by then. By middle June, they've grown and produced seed and then they start to shut down and grow dormant." Depending on the ranch, Olilla estimated that about eighty percent of the plant composition in western South Dakota is cool season grasses.
Grazing half and leaving half also leaves plant residue, which catches snow, decomposes and becomes cover. Having plants — dead and alive — cover the ground holds moisture, lessens erosion as raindrops hit residue instead of dirt and cools the soil. "When we get into our 100-degree days," Olilla said, "the soil remains cooler when it's covered and the roots continue to function. If you have bare ground and it gets to 120 degrees at the surface level, they shut down."
Ranchers who use the "once-through" gazing plan can switch up when that pasture is grazed each year. If a pasture is the first one cattle or sheep are turned out to one year, maybe the following year it should be deferred and be the last one grazed. The advantage to that, Olilla said, is allowing the early cool season plants to go to seed, and providing plant diversity. Wild onions, wild celery, and many early growing forbs (also known as broadleafs) will produce seed right away, but if they are grazed, they won't.
Another method is twice-through grazing, which is used by producers in south central and southwest South Dakota who have more warm season grasses. Flash grazing is also an option: in early spring, ranchers put stock on grass and take them off quickly, taking less than half of the forage. As some of the early cool season grasses are popping up, livestock grazes them and are pulled off that pasture. Usually there is enough early spring moisture so the plants grow back quickly.
Yet another method is managed intensive grazing. Livestock is in one area for a day then moved, not to return for a year. This method requires more labor in moving stock, and is a newer practice, used to improve grazing efficiency.
"People are trying to get more out of their rangelands but at the same time improve rangeland health," Olilla said.
Some ranchers move stock three times within a day, to new grass, even in open winters. It's designed to reduce or eliminate the need to feed hay.
"What would you rather be doing? Looking at the back of a cow (while moving them) or putting up hay?" Olilla said. "The goal of ranchers is to not feed hay all year, and prior to this year, some of them did well with our open winters."
Ground put into production, which is usually forage in western S.D., doesn't get the care that it often needs. Hay, grass, alfalfa, silage, and other forages are harvested and hauled off the field, with very little residue left. Minerals are also depleted.
"You're degrading your hay land, and mining those minerals but not putting them back," Olilla said.
A practice that at one time was common is bale grazing: allowing cattle to feed on bales in the field, where they were baled. In Olilla's experience, there is very little waste, and the plants are "recycled." Under some grazing conditions, "Eighty percent of what goes into a cow comes out of the cow," he said. "You're putting organic matter back into the ground." Sheep pass through 85 percent of what they eat, and will graze range plants that are harder to digest. The urine goes into the soil as ammonium nitrate, and in the fecal material as nitrogen. There's also less run-off into waterways because it's not as concentrated. Bale grazing saves on time and money as well: bales don't have to be transported to a bale lot or taken to the corral. Of course, bale grazing doesn't work under extreme weather conditions, such as heavy snow cover and wind exposure, when cattle are brought closer to home so they are easier to feed.
A different approach
On the east side of the river, things are a bit different. But soil health is just as important.
For Dennis Hoyle, a farmer who lives 35 miles west of Aberdeen, S.D., the number one resource for any farmer or rancher is their soil and their land.
Hoyle, a self-described "mad scientist at heart," has been practicing no-till farming — not disturbing the crop ground by turning the soil over — for the past 30 years, and explains soil health like a three-legged stool: infiltration, organic matter, and biology. If all three legs can be improved, then soil health improves as well. Improvement in two of the three legs brings improvement in the third.
Infiltration, the act of water permeating the soil, is best improved by leaving the plant in the soil. If there are no plants to slow or stop water running down a hill, it takes something with it: dirt. And if the ground has been fertilized, the water will take fertilizer with it, possibly degrading water quality.
The second leg on the soil health stool is organic matter. Increasing organic matter in a field is done by leaving crop residue, allowing it to decompose and add organic matter to the soil.
"Every time you turn the soil over, you expose it," Hoyle said. "Now when it rains or the wind blows, it takes something with it." It's not how his father or grandfather farmed, with the technology they had available to them. "The technology my father (Ben Hoyle) and grandfather (Warren Hoyle) used was a mold board plow, which turns the soil upside down."
Raising organic matter in soil helps tremendously in holding water. Hoyle has found studies that show that for a one percent increase in the organic matter in soil, it will allow an acre of land to hold between 16,000 and 20,000 gallons of water per acre.
"It's an advantage," he said. "It's a win-win if I can keep (the rain) where it falls."
The third leg of the stool, biology, consists of the microbes in the soil. The more microbes there are in the soil, the healthier it is. "Somebody referred to biology as the 'herd below the ground,'" Hoyle said. The most recognizable symbol of life in soil is the earthworm, but bacteria and fungi are also present. Worms create tunnels, which allow water to infiltrate the soil, and they digest residue, turning it into worm castings, which are a natural fertilizer. With microbes and worms, "you're making a sponge out of your soil and letting water infiltrate," Hoyle said.
Keeping it covered
Hoyle, who farms the traditional crops of corn, soybeans and wheat, believes strongly in cover crops. They improve infiltration, provide organic matter, and their root system brings nutrients back towards the surface that may be too deep for the regular crop. Plants such as turnips, radishes, sunflowers, and sweet clover are good cover crops.
"Some people call turnips and radishes storage tanks," Hoyle said. "They mine nitrogen and phosphorus out of the deep zone and bring it to where it's useful again." Hoyle plants about ten different cover crops, to get more diversity, because each does something a little bit different to the soil.
Planting cover crops also keeps something living in that soil as long as possible. As soon as wheat is cut, Hoyle plants a cover crop. Soybean and corn harvest is sometimes too late for a second crop. "It's good for soil health to have something alive, a living root as long as possible, throughout the year," until it freezes. "We want roots feeding the biology as long as possible."
Many ranchers and grass managers are already practicing the principles of rangeland health, Olilla said, and Hoyle said he learned the practices from his dad and granddad.
"Grandpa said, take half and leave half (regarding grazing). He taught my dad that, and my dad taught me. It's been an ethic taught to me since I was a little kid, to take care of the land."
Changing isn't easy, either, Olilla said.
"A lot of people continue to do what they do because it's always been done that way. We don't change unless we're moved to change."
He sees finances as an agent of change: ranchers and farmers are more likely to make soil health improvements if there's a monetary gain in it.
It all boils down to making better use of natural resources, while improving the soil and reducing expenses, Olilla said. Raising livestock and crops in the northern Great Plains isn't easy; improving soil health can help.
"We live in a land of extremes," Olilla said. "You play hell trying to raise things out here. You need to listen to mother nature." F