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Mimicking Native Prairie Keys Soils for the Jorgensen Land and Cattle Company
If you want to find the cornerstone of the 12,000 cropland acres no-tilled by the Jorgensen Land and Cattle Company, look no further than the farm’s 7,000 acres of native grass pastures.
“Those native prairie soils will teach you more about what Mother Nature does than any symposium, any soils professor, any university,” says Bryan Jorgensen, who manages the farm’s crop production component with his son, Nick, near Ideal in south-central South Dakota. “You can learn so much from them.”
Plunging a spade into native prairie reveals system that thrived for centuries before European settlers tilled it. These undisturbed and crumbly soils:
- Oozed with rich carbon and organic matter levels that helped store moisture and nutrients.
- Supported a thriving microbe community that helped plants absorb nutrients.
- Formed soil armor from surface vegetation that kept soil macropores open. When torrential rainfall occurred, these macropores enabled water to infiltrate the soil rather than run off or pool on the surface. This surface blanket also curbed wind and water erosion and helped retain scant moisture during drought.
Granted, farmers can’t do what Mother Nature did. They can come close, though. In 2015, The Jorgensen family’s commitment to soil health was recognized when the farm was honored with a Leopold Conservation Award. This honor recognizes outstanding voluntary conservation by private landowners.
How to Build Soil Health
The Jorgensens started no-tilling in 1990. “The key thing in building soil health is not tilling it up,” says Jorgensen. “No-till is a huge, huge part of building soil health.”
No-till was just the start, though. The native prairie sported an array of grasses, forbs, and native flowers that protected against erosion while nurturing soil life. A crop rotation can mimic this native vegetation through a mix of grass and broadleaf crops.
Corn is one of the Jorgensen’s largest crop, as it’s planted on around 2,500 acres for grain and earlage.
“After corn, we plant grain or forage sorghum,” says Jorgensen. “Milo (grain sorghum) is a good warm-season crop. It’s less expensive for us to grow milo, and it makes good high-moisture feed when we harvest it at 28% moisture.”
Oats, spring wheat, field peas, or soybeans often follow sorghum. Alfalfa also is used to break up rotations on certain fields for four to five years before a grain or oilseed crop is once again planted.
“We also have 1,000 or so acres of tame grass (for hay), such as intermediate wheatgrass and crested wheatgrass, that we rotate on poorer soils,” Jorgensen says. These soils, which tend to have drainage issues, are kept in tame grass as long as it takes them to be rehabilitated.
Winter Wheat Keys Cover Crops
Forty years ago, winter wheat-fallow was the predominant rotation in central and western South Dakota. Fortunately, the 2 to 4 inches of precipitation saved by no-till nixed the need for a fallow year in many cases. The 2,500 acres of winter wheat the Jorgensens grow for certified seed also help pave the way for a third soil health tool: cover crops.
Cover crops also can be aerially seeded or seeded in soybeans or corn, but stand establishment is sketchy.
It’s easier with winter wheat. The Jorgensens drill cover crops following midsummer winter wheat harvest. Normally, this gives the cover crop ample time to germinate and to grow prior to a fall killing frost.
“Anytime there are not living roots – such as after wheat harvest – is when you want a cover crop,” says Jorgensen. “If that live root system is not there, all the soil biology goes dormant.”
Drought can deter midsummer seedings. “Sometimes, we will have 3- to 4-inch cracks in the soil,” he says. “It is tough to get a good stand of cover crop because it is too dry to germinate the seed. So sometimes, we have to rely on fall rains to get late germination in the fall.”
Cover Crop Mixes
Cover crops have different attributes. Some like barley scavenge excess nitrogen (N). Some brassicas like turnips soak up excess water and shatter compaction. Others like oats form arbuscular mycorrhizal fungi associations.
“That’s one microbe that’s catching much attention,” says Jorgensen.
Research from USDA scientists Mike Lehman, Wendy Taheri, and Shannon Osborne shows these fungi – present in nearly all cover crops except brassicas like radishes and turnips – can acquire phosphorus (P) and other nutrients from the soil. That’s been borne out in the Jorgensens’ fertility strategy where P applications have been drastically decreased since 1995.
“In my opinion, adding excessive amounts of phosphorous to our soils, especially on higher pH soils like ours, is a poor investment,” says Jorgensen. “Phosphorous is readily tied up in soils, and only microbial activity and time can make it plant-available. We prefer to use sources that are applied with the seed and are readily available. The only P we add is 11 pounds per acre on most all crops in a starter orthophosphate form. We have pulled samples from cover crop soils where the level of available P was three times that of soils with no cover crops. That tells me cover crops sustain many forms of biological life to help the soil.”
To boost nutrient efficiency, the Jorgensens also boost stream band N and sulfur besides the seed with both the corn planter and air seeder. This method lowers overall applications by 30% to 50% and boosts nutrient availability to plants vs. spreading larger concentrations on the soil surface.
Cover Crop Cocktail Complications
Normally, the Jorgensens include a mix of grasses, legumes, and brassicas in their cover crop mix. These cover crop cocktails bring benefits, but they also are more complicated to manage. That’s particularly true when it comes to balancing carbon (C) and nitrogen (N) in the soil. Soil C provides food for soil microbes. These bacteria and fungi release the ammonium that adds N for a cash crop.
Ideally, soil microbes thrive at a 24:1 C:N ratio (24 parts C to 1 part N). Some cover crops, though, can throw this out of whack. For example, straw from a rye cover crop has an 82:1 C:N ratio. Soil microbes that tie up N could potentially create a soil N deficit until some microbes die and release N via mineralization.
This level can be brought down, though, by adding a hairy vetch cover crop with a C:N ratio of 11:1. Microbes will consume the vetch and leave the excess N in the soil for soil microbes to devour.
“There are many variables to consider for cover crops,” says Jorgensen. There are good tools on the internet to help you do this.
Here’s one excellent web tool the Jorgensens use that’s established by USDA-ARS for determining cover crop mixes.
Cattle form the heart of the Jorgensens’ farm, started in 1909 by Martin Jorgensen, Sr. When performance testing was just a gleam in the eyes of most cattle producers, his son, Martin Jr., pioneered this tool for tapping superior cattle genetics in the 1950s. He started a line-breeding program that is now one of the most line-bred Angus herds in the country. Today, the 93-year-old Martin Jr., and his wife, Mary, have turned over the cattle reins to their son, Greg, and his son, Cody.
An outgrowth of this has been a program where the farm leases almost 3,500 bulls annually. This growing program enables cattle producers to tap the Jorgensens’ cattle genetics without having to care for bulls year round.
Cattle also link to no-till, diverse rotations, and cover crops in forming a sustainable system. Incorporating livestock into the mix is akin to when buffalo grazed the native prairie.
“This is the perfect scenario, with no-till and cover crops building up soil structure and cattle completing the (nutrient) cycle by consuming the crop residues and spreading their own manure,” Jorgensen says.
“We have to have them in feedlots eventually, but at certain times of the year, animals can be on the hoof and do the work themselves. Cover crops are best used by grazing in late fall to early winter. “If you can’t graze, consider flattening the residue to aid in decomposition,” he says.
Cover crops also aid the farm’s hunting enterprise that’s run by Cody Jorgensen.
“Pheasants and deer love cover crops,” says Jorgensen. "The spring when we don’t have cover crops, pheasants nest in winter wheat in our part of the world.”
Bryan Jorgensen is featured in Successful Farming magazine's "10 Successful Farmers" article on page 22 in the June/July issue.