Beneath the green-velvet hillsides of Palouse wheat lies frightening evidence that farmers are slowly burying their most crucial asset - the topsoil.
In a dramatic demonstration Wednesday before 1,500 farmers attending Monsanto’s Fields of Tomorrow tour, soil scientist Alan Busacca unearthed proof that farmers are not just eroding their hilltops, but are covering the topsoil with tons of clay subsoil, effectively burying future production of grain that feeds the world.
“There’s been a real impact on soil productivity,” the Washington State University researcher said. “In the past, we’ve kept ahead of it with plant breeding, nutrition management and disease control. But this has glossed over the effects of soil erosion.”
Busacca’s discovery was an endorsement for advocates of no-till farming - the growing practice of drilling, or seeding, crops directly into stubble to reduce erosion and passes across a field. He said that was one of the few ways to arrest soil erosion on cropland.
The demonstration also showed the potential tragedy of converting hilltops and slopes idled under the 10-year Conservation Reserve Program contracts back into cropland, as many farmers are expected to do this year.
“Ten years isn’t enough time to bring back significant amounts of organic material,” Busacca said. “It takes hundreds of years.”
Cutting a 5-foot deep, 200-foot long trench along the side of hill near the Palouse Empire Fairgrounds, Busacca pulled back the skin of the earth like a surgeon searching for a suspected cancer.
As expected, the top of the hill was bald with clay subsoil - the result of a century of plowing, rainfall and gravity carrying layers of topsoil down hill. Tons of rich, black topsoil were deposited at the bottom, where crops could grow successfully for generations.
But along the middle slope, where farmers had expected to see a gradual change in the depth of the topsoil, were the “ribs of a dead animal,” Busacca said. Clay from the top of the hill had pushed through and over the topsoil, burying the organic material that plant roots need to produce healthy crops.
“So that’s my trouble,” whistled one grower as he and hundreds of others reverentially peered into this dirt grave of poor farming practices.
In a later interview, Busacca said farmers working steep Palouse slopes may have lost 20 percent to 40 percent in crop yields because of erosion. For a wheat crop, that could be worth $100 an acre.
“It’s a tribute to farmers that they’ve maintained the yields they’ve had, but the debate is whether they can keep it up,” Busacca said.
“We knew erosion was a problem, but even I was surprised by this,” he said pointing at the trench. “Erosion is slow and deceiving and it happens in the face of the lush fields which we see around us.”