Calling it a “quiet crisis” in 2018, Ohio State University professor of soil science Rattan Lal said soil loss is a major issue that has been affecting farmers around the world for centuries.
“The best practices are to not plow, keep the ground covered with residue and grow a cover crop in the off-season,” Lal said. “It could be a cash crop or a cover crop. Many of our good farmers are doing it.”
But it goes beyond individual farmers. Lal said his goal is to see these conservation tactics better incentivized through policy. He said a plan that would offer around $16 per acre to farmers who are actively participating in conservation practices would offset losses and improve soil health and water quality.
“If society benefits from farmers doing no-till with a cover crop and the farmer has to suffer 5-10% less yield, society should be willing to compensate them for doing things that will improve water quality, decrease the emission of greenhouse gasses and reduce global warming,” Lal said.
He gets his $16 figure from an article he wrote in 2014 for the Soil and Water Conservation Society. He details different factors balancing the need for food production and the desires of the Obama administration at the time to reduce U.S. carbon emissions. One aspect of policy discussed was how the U.S. has a Clean Water Act and a Clean Air Act, but no healthy soil act.
“We can never have clean air and clean water without healthy soil,” Lal said. “... It is a three-legged stool: air, water and soil. Right now we have a two-legged stool and that’s when we have a problem.”
Lal said some farmers in the Midwest could do a better job with adapting continuous no-till practices. But he said some farmers go no-till for a year before they chisel-till the next year, which he would like to see reduced.
Mahdi Al-Kaisi, an Iowa State University Extension soil and water specialist, said some farmers use tillage and nitrogen applications to increase residue decomposition, but that might be counterproductive from a financial and environmental perspective.
“Environmentally, both tillage and this fall N application are not very sustainable practices,” Al-Kaisi said. “Tillage can contribute to soil health and water quality deterioration by increasing soil erosion potential, sediment loss and water quality degradation, and fall N applications result in water quality risks.”
Al-Kaisi said the applications can also be costly with materials, time, labor and equipment required.
In an Extension article, Al-Kaisi wrote about a three-year study of three different tillage systems (deep tillage, strip-tillage and no-till) that showed there wasn’t much difference in the residue breakdown in these systems.
However, during testing Lal has found about 15% of carbon matter added actually stays in the ground after a year. That means additional cover crops, having a good rotation, building a bioreactor or even looking into agroforestry are possible options to explore to maximize the amount of carbon that sticks in the soil.
“Most of the knowledge is known,” Lal said. “It’s a question of translating that knowledge into action. And that action requires a policy.”