Workshop speaker outlines considerations for revegetation on disturbed sitesWritten by Natasha Wheeler
Douglas – “Every part of the state is different. The soils change, the climate changes, the economics change, regulations change, and personalities change,” remarked Brenda Schladweiler of BKS Environmental Associates, Inc.
Schladweiler spoke about preparing reclamation sites for revegetation at a reclamation workshop, hosted by University of Wyoming (UW) Reclamation and Restoration Center and UW Extension.
“It’s hard to come up with a silver bullet for any given site,” she said.
Topsoil, for example, varies in composition from site to site, but it also varies by definition.
“There is a strict definition in the taxonomy world – the strictly soil science world,” Schladweiler noted.
But in the practical world of reclamation sites, topsoil and subsoil are often mixed together.
“A bentonite mine probably salvages topsoil separate from subsoil, but they may be the only mines in the state that do that because they have high clay to deal with. The difference between 40 percent clay in the topsoil and 60 percent in the subsoil is huge,” she explained.
Coalmines, on the other hand, don’t often have a practical reason to separate the two, and oil pad sites may or may not find it beneficial, depending on the location.
“Minimize the amount of soil handling,” Schladweiler suggested. “If we know we aren’t going to re-disturb that site, we can put the soil back on it and do interim reclamation. But, in some ways, I would rather see a bigger stock pile if we are going to re-handle that topsoil two or three times.”
Avoiding wet and frozen soils can also promote soil health for revegetation to be more successful.
“Also, used tracked equipment if possible. Rubber-tire equipment will compact the soil,” she added.
Erosion control is another important factor to consider at a reclamation site that will eventually be revegetated.
“If we windrow topsoil, or at least rip it in rows or tracks, we’re going to minimize both wind and water erosion, depending on which way we put it on the landscape,” commented Schladweiler.
Especially in sandy soil areas, like much of Wyoming, high winds can move large amounts of soil, sandblasting seedlings or exposing roots that have not yet grown deep enough to reach moisture and stabilize the ground.
“I think imprinting is a great option in certain parts of the state or in certain areas,” Schladweiler continued.
Imprinting is also known as pitting and consists of digging shallow holes that can trap snow and water.
“This is really important in the Bighorn Basin where they only get around six inches of precipitation,” she said.
Rock berms can also be used for erosion control because they create a windbreak and catch snow.
“Anything in the landscape that catches snowfall is so important in this area,” Schladweiler commented.
In the planning stages, she suggests looking at the landscape and recording which areas collect snow or moisture.
“Mother Nature is going to give us a good indication of where or what types of things might help,” she explained.
Schladweiler also discussed interim vegetation, giving native plants a chance to establish and grow. For example, Russian thistle can be used to protect new plants.
“In that first growing season, all we have to do is kick up a Russian thistle with our boot, and we will see lots of baby grasses underneath,” stated Schladweiler. “It captures moisture and prevents grazing.”
The key, she added, is to keep the thistles from getting too big. Mowing them, for example, prevents them from blowing away and spreading seeds across the landscape. Eventually, the plants will crowd each other out, and native plants will be able to take over.
“About the third growing season in this country, Russian thistle will go away,” predicted Schladweiler.
Soil nutrients and microbial activity were also covered by Schladweiler, who suggested getting soil tests and keeping the soil fertile for microscopic organisms.
“Know what kinds of soils we have before we salvage them. A little bit of planning goes a long way,” she remarked.
Planning is helpful for establishing a good seedbed as well. Seed size, soil moisture and soil type will all affect how a seedbed should be prepared.
“Are we in clay? Are we in sand? Do we have loam?” Schladweiler questioned. “What kind of equipment do we have? Are soil amendments needed? Is this the right time of year for moisture conditions?”
Seed mix components and application procedures will change, depending on the many different factors of each location.
Once vegetation begins to grow, the new plants also need to be protected.
“Restrict human activity,” Schladweiler said. “Also restrict livestock and wildlife activities where possible.”
One suggestion she made was to keep the ground pitted to reduce vehicle traffic, since the uneven ground makes for a rough ride in the pickup.
“Signs are important,” added Schladwelier.
Marking defined areas for reclamation and areas where traffic should be directed can prevent excessive disturbance across the site.
“Many agencies are going to want close disturbance monitoring,” she stated.