Building healthy, productive, resilient soils was the topic of two events last week featuring nationally known USDA NRCS Soil Scientist Jay Fuhrer.
Fuhrer spent a day in Viroqua with Youth Initiative High School (YIHS) students on Friday, May 19 teaching about building healthy soils. The YIHS students then provided a delicious dinner to the 40 participants attending an evening presentation by Fuhrer at the Ark in Viroqua.
On Saturday, May 20, about 50 local farmers and friends gathered in the Mt. Sterling Village Hall to listen to Fuhrer talk about his work.
Fuhrer conducts his research on the Menoken Farm in Bismarck, North Dakota. In his presentation, Fuhrer shared an image of a Bakken oil train travelling alongside his field of cover crops.
The soil scientist pointed out the contrast between “old sunshine oil” and “new sunshine oil.” He urged farmers not to neglect the opportunity to reap the benefits of the new sunshine oil through green, growing plants.
The area, where Fuhrer farms, was once dominated by what is widely considered to be one of the best natural soil-building systems on the planet—the prairie.
The 300,000 acres of native prairie remaining in North Dakota are home to 75-125 species of plants per acre, with 7 to 8 percent soil organic matter.
This multispecies, perennial landscape provides a stark contrast to the monoculture annual landscape that has replaced it. The latter typically being home to just one plant species.
“In our cultivated fields, we see 50 percent less soil organic matter than in the native prairies,” Fuhrer noted. “This means there is a huge carbon gap in our cultivated soils, and we have tremendous storage capacity for greenhouse gases which are useful in soil building, but harmful when released into the air and water.”
Where the soil food web used to receive sugars in the form of carbon exudates from a diversity of perennial plants harvesting sunlight and carbon dioxide, it now receives them from only one annual plant at a time.
“Growing a monoculture puts soil life on a restricted diet,” Fuhrer explained.
Fuhrer pointed to a new area of study in agriculture known as ‘bio-mimicry,’ an approach to innovation that seeks sustainable solutions by emulating nature’s time-tested patterns and strategies. His agricultural research on the Menoken Farm is focused on soil restoration, by mimicking the native prairie of the region.
“Carbon is the currency of exchange in the soil, just like the dollar is in our economy,” Fuhrer said. “Building healthy soils with good (water) infiltration, a strong structure, and ample nutrients requires finding ways to capture and retain carbon to feed the soil microbiology.”
Fuhrer responded to a common objection about the additional costs associated with planting cover crops.
“Does it cost money to plant cover crops – yes,” Fuhrer acknowledged. “But the thing to remember is, it also costs money not to (plant cover crops).”
He stressed that farmers had gotten into trouble thinking only about the front end of cropping, and ignoring the back end.
“We have to figure out how to treat the problems, and not just the symptoms,” Fuhrer said.
Soils are alive. It is often said that a handful of soil has more living organisms than there are people on Earth. Soils are the stomach of the planet, consuming, digesting, and cycling nutrients and organisms.
Soil health is defined by Fuhrer as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals and humans.
In his research, Fuhrer’s basic premise is that we can start to mimic the original plant community by using diverse crop rotations. Such rotations provide more biodiversity, benefiting the soil food web. This in turn improves rainfall infiltration and nutrient cycling, while reducing disease and pests.
“Diverse crop rotations are important to the long-term sustainability of our soils and to food security.”
The five principles Fuhrer puts forward in his prescription for building healthy soils are Soil Armor, Minimizing Disturbance, Plant Diversity, Continual Live Plant/Root, and Livestock Integration.
Soil building essential
Fuhrer told event participants that farmers in his area had approached him, reporting they were now farming 15 percent fewer acres than in previous years due to salinity (salt) in the soils.
“We’re in an extraction business,” Fuhrer said. “It’s only so long that we can take before we have to start putting something back.”
“I used to think building soil was important, now I view it as essential,” he told the event participants.
Fuhrer explained that a third of the product of the field is in seeds, a third in the above-ground plant growth, and a third in the root structure of the plant.
“We can take the seeds, but we need to put the other two-thirds back into the soil if we want our soils to continue to produce the yields that will sustain our farming businesses into the future.”
Fuhrer urged farmers to leave post harvest debris on the field as “armor.” Armoring a field not only helps to reduce compaction by building the soil biology and air spaces, but also by protecting it against rainfall, a major source of compaction.
He has also found that the best way to deal with the aboveground third is to allow animals to graze the most nutritious top half of the forage, and then allow their hooves to trample the remaining half.
The roots should be allowed to remain in the soil, re-growing. They will then continue to re-harvest the remaining nutrients in the field and return them into the system as food for the soil biology.
“When you take the top half and leave the roots to continue to grow, you maximize the amount of carbon going back into the system,” Fuhrer said. “When the plant is disturbed, it dumps its root mass and starts the whole process over, removing even more of the residual inorganic nutrients.”
Fuhrer explained that only about half of the urea sprayed on a field is actually used by the plant. Without a cover crop, those nutrients are either excreted by the soils back into the air or they simply wash off into the surface waters.
“Farmers are decreasing their wealth by failing to keep the carbon in their farm system, and the end result is lower yields, algae blooms, and dead zones like the one in the Gulf of Mexico,” Fuhrer said.
Cover your stuff
“Cover your stuff and plant green” will be Fuhrer’s slogan as he continues and expands his efforts.
Fuhrer told event participants “we have to grow our water out, not till it out.” He said that sub soiling is just using the mechanism that created the problem to try and fix it.
Living plants transform carbon into soil organic matter, and build soil aggregates. Plants take CO2 out of the atmosphere, transform it into carbon and feed the soil food web. The roots of the plants build soil aggregates. Soil aggregates create air spaces, fighting compaction and increasing infiltration.
Farmers have two major opportunities for cover crops and carbon capture one in the spring and the other in the fall. However, they also have another opportunity during the growing season itself. Fuhrer has been experimenting with interplanting cover crops in between the cash crop during the growing season, and planting into an existing cover crop.
The soil scientist pointed out that it is actually easier to get out into the field, when there is green plant material in the spring. He also debunked the common myth that the soil won’t warm for planting if there is a green cover.
“Exactly the opposite is true,” he said. “When you have green cover, the soil warms both from above and below.”
“It’s easy to open things up to drill in the seed, but getting the soil to close around the seed planting into green growing plant cover is the challenge,” Fuhrer said.
Fuhrer explained that getting the soil to close becomes easier over time as your soils improve. He has been experimenting on his farm with different weighting of the equipment to optimize planting into green cover.
He works with Paul Jasa, an Extension Research Engineer, at the University of Nebraska at Lincoln. Jasa is an expert at weighting of planting equipment, and can be reached at 402-472-6715, or at email@example.com.