TERRE HAUTE — Earth Day typically features community cleanups, and discussions of air and water pollution. All deserve the attention.
But what about the actual earth, as in the dirt, soil, good old terra firma under our feet?
Most of us barely pay attention to the ground, unless we spot a molehill in the lawn or plant a garden. Farmers notice the dirt. It’s a source of their livelihood. For several decades, conservation farm practices have grown across the United States and beyond, primarily because methods such as “no-till” farming and “cover crops” keep the soil — as well as the water and air — healthier.
In a no-till field, the farmer doesn’t plow under the residue from the previous season’s crop. The earth is disturbed as little as possible, only for the planting of seeds and the injection of fertilizers. For example, a no-till farmer plants soybean seeds into a field still covered with stalks and roots left over from last fall’s corn harvest. The environment benefits in multiple ways. Soil erodes less in heavy rains, according to the U.S. Department of Agriculture’s Natural Resources Conservation Service, decreasing runoff of chemicals into streams and groundwater.
The microorganisms in dirt rejuvenate. A three-year Purdue University study found that no-till fields release smaller amounts of greenhouse gases — such as nitrous oxide — than conventionally plowed crops, and slow the breakdown of fertilizers, thus reducing the amounts needed.
Likewise, cover crops involve the planting of grasses, legumes or small grains in the offseason, between harvest and planting of corn and soybeans. The idea is to improve the soil, and protect it from wind and water erosion.
No-tilling and cover crops give something back to the soil.
That dirt is far more than a dead clump of damp dust. A teaspoon of soil packs more individual organisms than the number of humans living on the planet, the NRCS points out. The microbe population strengthens when the residual plant materials left through no-till and cover crops break down.
“We’re referring to those as another form of livestock the farmer needs to manage,” said Eddy Adams, district conservationist for the NRCS in Vigo County.
Denny Bell understands that viewpoint firsthand. The 54-year-old Purdue grad has farmed 2,000 acres of corn and soybeans in Vigo County since the early 1990s, using no-till methods.
Bell started with no-till because he had limited resources.
“Really, a tractor and a planter, and you’re in business,” he said, grinning at the memory of his lean beginnings.
The results aren’t simply altruistic. No-till farming has a profit, which, of course, is a necessity in the complex agricultural economy. As the soil improves, its productivity does, too. “I think I’m getting equal to higher yields with a lot less fuel, a lot less equipment, and a lot less labor,” Bell said last week. “Those are huge things. Long-term, I should be able to use less fertilizer.”
The adoption of no-till has been gradual in the United States. A column by University of Illinois graduate Mike Wilson on FarmFutures.com — an ag business website — pointed out that the South American country of Brazil has 75 percent of its crops planted through no-till, while less than half of U.S. crops are planted no-till. USDA research shows that 35.5 percent of U.S. cropland committed to the eight major crops — barley, corn, cotton, oats, rice, sorghum, soybeans and wheat — is done through no-till.
In Indiana, 70 percent of beans and 19.2 percent of corn was planted no-till, according to the USDA’s most-recent stats, 2005-06. Meanwhile, Indiana led the nation in the number of acres of cover crops in 2011. In Vigo County, some farmers plant deep-rooted veggies for cover crops, such as turnips and radishes, Adams said, in addition to rye grasses and clover.
No-till hasn’t grown as quickly in Vigo County. About 10,000 acres of the 150,000 total farmland acres in the county are managed through no-till, Adams said. He hopes to see that number increase as farmers become familiar with advantages of rebuilding the soil base. Full-time no-till farmers can offer evidence, and those people, Adams said, are “constantly trying to incorporate a different way of doing what they’ve been use to doing.”
Bell farms the same soil his grandfather once tilled in conventional fashion.
“I think Grandpa’d be liking what he sees here,” Bell said, gazing over the horizon in one of his fields. “God’s not making any more soil. So how are we going to take care of that organic matter?”