By Brooke Hatfield
University of Georgia
"The idea was, can we use (gypsum wallboards) to improve the soil?" said Julia Gaskin, an extension service land applications specialist with the University of Georgia College of Agricultural and Environmental Sciences.
"Wallboard is largely gypsum (calcium sulfate) with paper backing," Gaskin said. "Some states no longer allow it in landfills because mixing gypsum with organic matter, in the right amount of moisture, creates bacteria that produces sulfide."
Sulfide produces a rotten-egg smell. The mix can also be potentially explosive.
Piles of Sheetrock"Wallboard produces the second-highest amount of trash produced in residential construction," Gaskin said.
Wood tops wallboard, but it can be processed in environmentally useful ways. "They could use it as mulch, or send it off to be burned ... as fuel," Gaskin said.
The new recommendations could pave the way to gypsum wallboard, also known by the trade name "Sheetrock," being used popularly in a similar, environmentally friendly way.
Gaskin and her team have determined that gypsum wallboards can be used as a means of preventing soil crusting in clay soils, which would reduce runoff and erosion. The wallboard can also be used to reduce aluminum toxicity, which can prevent roots from implanting themselves deeply into soil.
Up until now, there haven't been guidelines for using ground scrap wallboard. With financial help from the Pollution Prevention Division of the Georgia Department of Natural Resources, that has changed.
Research-based guidelines"The guidelines were based on the extensive amount of work done in Georgia on agricultural gypsum," Gaskin said. "This includes the peach and alfalfa studies done by (UGA) Drs. (Malcolm) Sumner and (William) Miller."
Test plots applied with gypsum generally either had a small increase in yield or a normal yield. Peaches and alfalfa responded especially well to the gypsum.
"Generally, crop response to ground scrap wallboard is similar to agricultural gypsum," Gaskin said.
The gypsum didn't hurt crops unless large amounts were applied. "You can always overdo things," Gaskin said, "but if you do things properly, it can have a good effect."
The recommendations are based on, among other things, geographic location and soil makeup.
How it's usedTo use gypsum wallboards, they must be separated from other site debris. They then need to be ground. After this, they can be turned into the soil during landscaping.
"This may be something that can help homeowners, too," Gaskin said.
Wallboard from older houses isn't suitable, because it may have come into contact with lead paint or wallpaper. And most commercial contractors use Type X wallboard, which is 1 percent fiberglass. There are no recommendations now that advocate using Type X wallboard as a complement to the soil.
The wallboard recommendations have been approved by the EPD. The next step, Gaskin said, is to alert the building community to the potentially beneficial reuse.
"It may reduce costs," Gaskin said.
Gaskin worked with Clint Waltz, a UGA Extension Service turf specialist; Miller, a UGA professor of crop and soil sciences; and UGA horticulturists Mel Garber, Tim Smalley and Gary Wade.
(Brooke Hatfield is a student writer with the University of Georgia College of Agricultural and Environmental Sciences.)