Like livestock, soils requires balanced diet fueled by diversityWritten by Christy Hemken
Fuhrer was present at the early November joint meeting of the Society for Range Management Wyoming Section, the Soil and Water Conservation Society Wyoming Chapter and The Wildlife Society Wyoming Chapter in Cody.
Fuhrer was referring to a region-wide effort to rebuild soils depleted from intensive commercial wheat production.
“We had started into tillage systems with high amounts of summer fallow and season-long grazing on the rangeland,” he explained. “One day we sat down together and asked ourselves how long we could continue to mine the Great Plains. We needed to restore and reclaim, but how do you do that in a production ag system?”
“I started looking at the foundation blocks of soil health and how they relate to cropping/grazing systems using cover crops,” said Fuhrer, bringing up what he called the “three sisters” – corn, beans and squash. “A lot of the Native American systems were based on those three because they all brought something to the table and it was sustainable.”
“We went from low crop diversity – we were wheat people – to high crop diversity with no-till systems, eventually bringing in cover crops,” said Fuhrer. “We went from season-long grazing to pasture grazed less than a week each year. What we’re harvesting now in the Great Plains is sunshine, and there’s a lot more sunlight we can harvest in early-seeded crops.”
The shift began in 2006 when Fuhrer planted cover crops as monocultures and two- to eight-way mixtures. One thing he found was, with a little over one inch of precipitation in the 2006 growing season, an extreme difference between the poly- and monocultures.
“The soil temperatures were extremely different between the poly- and monocultures, and as the summer evolved the monocultures completely dried up, but the eight-way flourished and produced a little over 4,000 pounds of production on a little over one inch of precipitation,” he explained.
Fuhrer said ground cover is key to a healthy system. “When I’m talking ground cover, I’m talking significant,” he said. “It was one of our missing elements. The soil is alive, and like livestock you have to take care of its home and provide a food source.”
He said there’s no such thing as too much ground cover. “There’s no amount of cover you can’t no-till through,” he said. “And you get extremely uniform emergence, which comes from having a uniform cover crop.”
As an example he told of a field mechanically tilled for over 100 years, with the crop residue baled and taken off. The first year a field pea cover crop was planted and rolled down to cover the soil. “No rational person would do that, but he provided a cover the field had never had and you could hear the soil go into shock,” said Fuhrer. “Then we could start to reclaim.”
Following the field peas a mixture of cover crops was brought in. “Where a monoculture struggled we brought in an eight-way cover crop and they’re not competing – they’re helping each other,” he explained.
Fuhrer said his template for managing cropland is native rangeland, which has hundreds of plant species. “Diversity is what drives our systems. We brought those same crop types into cropland – cool season and warm season grasses and both seasons broadleaf plants.”
Following the initial experiments with mixtures in 2006 Fuhrer said 70 to 80 percent of the county moved to no-till systems, with 10 percent direct seeding and 10 percent that he said never will change.
“We went from primarily wheat to all four crop types, and through that a lot of our disease and insect pressures diminished,” he said.
Increasing crop diversity also increases water holding capacity in the soil. “A no-tiller builds soil aggregates, which builds pore space back in, which is what’s degraded with tillage,” said Fuhrer. “That little space is where the extra water is held, and where air can occur and where it all happens.”
Increasing diversity also increases cycling, or the amount of time required to incorporate crop residue into the soil system. Cover crops also help with weed suppression, which reduces inputs.
Regarding livestock, Fuhrer said a cropping system can be brought to a higher level if livestock are brought in. “A lot of good things happen with integration,” he said, in soil nutrients and especially in the way the cover crop’s harvested. “It’s chopping versus grazing, and the cattle have legs. What we’re moving to in North Dakota is bringing the cattle to the land.”
“Crop diversity provides a balanced diet for the soil,” said Fuhrer. “Wheat does not provide a balanced diet – it’s only one food source for the soil biology. Soil organisms are like livestock – they require a balanced diet to attain high performance.”