First, the good news: Every U.S. farmer feeds 166 people. U.S. corn yields have tripled since 1960. U.S. wheat and soybean yields have doubled in that time frame. Worldwide, the “Green Revolution” of the 1960s and 1970s fueled by famed crops breeder Norman Borlaug saved millions of people from starvation, due to high-yielding and disease-resistant wheat varieties.
“It’s a great story,” says Rattan Lai, an Ohio State University soil scientist and 2020 World Food Prize winner.
That was then, though. “Great challenges lie ahead,” says Lai. Rattan told those attending this week’s Soil Management Summit in Mankato, Minnesota, that a new Green Revolution based on soil resilience is now needed. That’s because:
Still, agriculture holds a solution in its soil.
“Soil is life,” says Rattan. “There is no soil without life, and no life without soil. We don’t need more land. We need to better use what we have.”
To combat nutrient leaching and soil erosion and decomposition, the following tools can act to sequester carbon and combat greenhouse gas emissions:
- Biochar
- Compost
- Cover crops
- Root biomass
- Crop residues
Systems that pay farmers for carbon sequestration and preventing greenhouse gas emissions are also necessary, he adds. “Farmers who are the greatest stewards of natural resources must be rewarded,” he says. Many companies are now doing that, he adds.
Control Erosion
Farmers who aim to sequester carbon, though, first need the soils to do it. That’s why nixing erosion is key, says Jodi DeJong Hughes, a University of Minnesota Extension educator. There’s good news on this front. “Erosion in the U.S. has dropped 25% in the past 40 years due to conservation practices,” she says. “But the erosion rate is still 10 to 15 times higher than the amount we can replenish it [soil]. So, we keep trying more and more conservation practices to drive that number down.”
A critical part of this is keeping ground covered from fall to spring after the cash crop is harvested, she says. Sometimes, there’s luck involved with winter erosion protection. “If you have snow cover, there is less erosion going on,” she says. Without snow, though, unprotected land lies at the mercy of wind that can create massive soil loss through erosion. “Last year (2020) on December 23, we had a major event with no snow cover and 60 to 70 mph winds,” she says.
It doesn’t get any easier on the rainfall front. Higher intensity rainfall erodes soils and drowns plants. Denitrification in saturated soils can result in losses of 2 to 4 pounds of nitrogen per acre per day, she adds.
“We are also experiencing more prolonged droughty periods,” she says. “So, if we get rain, we need to get it the soil, and we can do it with soil health practices. We need to keep our soils covered with living crop residue.”
If you’re concerned about spending oodles of money to revamp your machinery line to do this, relax. Changes can be gradual. “It doesn’t need to be 100%,” she says. “Devising a way to cover ground at 50% can also protect soil.”
For example, a shift to less aggressive points or shanks on a chisel plow can cut soil disturbance, she adds.
Make it Personal
There are plenty of agronomic reasons to switch to soil health practices like less tillage. Still, science doesn’t always key change. Emotions do.
DeJong-Hughes notes that favorite farm memories — ranging from fishing with a grandparent in a local pond or river or a family having a field dinner at the end of a pickup during harvest — can all be connected to soil health. Without soil health, a pond may fill up with sediment and host algal blooms. Maintaining and increasing crop yields and saving soil through soil health practices can also make it possible for families to pass the farm onto the next generation.
“Whether we know it or not, all those things are associated with soil health,” says DeJong-Hughes.