Alabama ahead of curve in soil conservation

In the view of some experts, it represents as big a threat to our environment as global warming — the slow, unrelenting skinning of planet Earth.

“On average, the planet is covered with little more than 3 feet of topsoil — the shallow skin of nutrient-rich matter that sustains most of our food and appears to play a critical role in supporting life on Earth,” writes the Seattle-Post Intelligencer’s Tom Paulson.

Unfortunately, across many parts of the planet, this thin brown layer is becoming even thinner — in Washington state by as much as 1 percent each year, according to David Montgomery, a University of Washington geologist quoted by Paulson.

As a result, growing numbers of farmers in Washington are trying to persuade fellow producers to adopt no-till farming methods, which involve not tilling land between planting, leaving crop residue to reduce erosion.

So why aren’t soil experts in Alabama expressing similar worries? Actually, they are — for farmers in Washington state and other parts of the country, though not as much for farmers in Alabama.

“This is very true of the Palouse in Washington state,” says Charles Mitchell, an Alabama Cooperative Extension System agronomist and Auburn University professor of agronomy and soils who has been involved in soil conservation issues throughout his career.

But it’s a different case entirely in Alabama, where soil concerns pale in comparison to those of Washington state. Why? Partly because Alabama producers got serious about the threat of soil erosion years ago.

In fact, they had no other choice. Indeed, Mitchell is old enough to remember when “the Tennessee River ran red for six months of the year.” Likewise, Lake Martin “always had a reddish hue from the clay silt sediments in the water,” he recalls.

While the fight against soil erosion may have started out as an act of desperation, Alabama producers have made huge strides toward reversing what initially posed a serious threat to farming.

“Maybe it is because we lost so much topsoil during the 19th century and first half of the 20th century that we simply did not have any more topsoil to erode,” Mitchell says.

No-till farming practices adopted within the last few decades at the urging of Extension educators such as Mitchell as well as other land-grant university educators and officials with the Natural Resources and Conservation Service have played a major role. But so have other state and federally sponsored efforts, including reforestation and conservation programs, Mitchell says.

Despite this progress, Mitchell says that environmental threats still loom — one of the biggest being the effects associated with development.

The explosion of concrete and asphalt landscapes within the last few decades impedes the replenishment of groundwater. Instead, rainwater runs off and contributes to downstream flooding.

For those suburban developments with little opportunity for rain to enter the soil, the typical result is compacted subsoil — a hostile environment for growing turfgrass and shrubs, the sorts of plants that “do little to replenish the oxygen that used to be provided by forests, pasturelands and cropland,” Mitchell says.

For these reasons, the biggest challenges in the future will be surface water and groundwater quality and quantity, he says.

Topsoil also will be a major concern, though not in the way it has been in the past, Mitchell says. Rather, it will be on how topsoil will be managed in the future to clean our atmosphere.

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