By Brooke Hatfield
University of
Georgia
For years, gypsum wallboards have been carted from construction
sites to the landfill. But now scientists say they can be used
to
improve lawns.
“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 used
To 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.
