Trash or Cash Commodity?
Johnny Henderson, mayor of Enterprise, Alabama, says his town generates 20
to 30 tons of yard waste a day and charges property owners $17 a ton to take it
to a landfill. Believing it would be smarter to sell or even give away the yard
waste, Henderson turned to James H. Edwards, Jr., for help.
A soil scientist with ARS National Soil Dynamics Laboratory at Auburn,
Alabama, Edwards has spent the past several years finding ways to use different
combinations of yard waste, paper, poultry litter, and other waste materials to
grow cropsoften with higher yields and at less cost, both environmentally
Two years ago, in response to Hendersons pleas for
help, Edwards started a study of ways to safely apply composted yard waste to
farmland around Enterprise. Many of the soils in the Southeast, as well as in
other parts of the country, are low in organic matter that the yard waste can
Waste materials tend to concentrate in one spota
landfill, chicken farm, wastewater treatment plant, or factory storage area.
Usually these materials have a value so low people have to pay for disposal.
Transporting them farther away to sell where they are needed may not be
Small pellets used as landscape mulch.
But if you blend two or more of these waste materials
together in the right way, the product may have enough value to warrant
shipping. The way Edwards and his ARS colleagues Ron Korcak and Larry Sikora in
Beltsville, Maryland, see it, these products could be natural substitutes for
pesticides, mulches, fertilizers, and other soil amendments needed by farmers,
landscapers, and gardeners.
In their vision, farmers near urban areas would compost various wastes and
charge cities less than landfill fees, while providing compost for city
dwellers. They could also take in waste from other farmers and return it to
them as compost for a fee.
Of course, farmers could also use the compost themselves, reducing the costs
of inputs to their production systems. And if enough value were added, they or
recycling industries could sell the products beyond the region where the wastes
were initially generated.
Composting Gypsum Drywall and Wood Scraps
This month, the U.S. Department of Agriculture is opening a
model composting facility at the 7,000-acre Beltsville Agricultural Research
Center (BARC) near Washington, D.C. It will mainly handle manure and other
wastes such as potting soil and plants. It will also have an area set aside for
research to find out which blends of materials make the best compost. In
addition to farm and yard waste, the BARC scientists will test materials such
as scrap wood and drywall from construction sites, residues washed from cement
trucks, waste from crab processing plants, and ash from coal-fired electric
They will also use the facility to explore whether microbes can be added to
compost that will promote plant growth and aid in preventing plant disease.
Korcak is experimenting with turning the ton of drywall
scraps cut away to finish the inside walls of the average home into a soil
additive that will help grow a new lawn around it.
As one possibility, he and Peter Yost, who is with the National
Homebuilders Research Center in Upper Marlboro, Maryland, see
construction workers using a portable machine to pulverize drywall and wood
scraps on site. These pulverized materials would be mixed with fertilizer into
the topsoil, rather than carted off to a landfill. The Gypsum Association of
Washington, D.C., is funding the drywall part of the project.
Or the drywall and wood scraps could be brought to a central composting
facility for blending with the scraps of other enterprises, adding more value.
Yost sees land application as one of the most promising ways to accommodate
the large volume of drywall trimmed away to make the walls of many homes in
America. Wood and drywall scraps are the two most abundant wastes at
Yost calls drywall scraps a commodity, while Korcak and his colleagues call
their materials resources. Instead of waste or scraps,
they see inexpensive ingredients for commodities that can enrich both soils and
Compost Pellets for Easy Handling
Soon your home fertilizer spreader may be spitting out old newspapers and
telephone booksin pellet form.
Edwards has signed a cooperative research and development agreement with a
recycling firm, Tascon, Inc., of Houston, Texas, to make the pellets and other
products for farm and garden use.
Tascon president Jim Adamoli says he is already selling recycled paper mulch
for flower gardens in both shredded form and as pellets.
The paper can be spread by hand on a flowerbed, like pine bark mulch, or
incorporated into the soil with a home or farm fertilizer dispenser. For use as
a fertilizer, Tascon fortifies the paper with poultry manure, heats the mixture
to 160° F to kill possible pathogens, and then extrudes it as pellets.
Adamoli has his eye on setting up plants in rural areas around the country.
Alabama is one of the states he is considering, because its poultry and
horticultural industries provide natural markets for the recycled paper as
bedding and mulch.
For the past 4 years, Edwards has tested shredded newspaper and telephone
books on corn, soybeans, cotton, tomatoes, collards, and other vegetables. When
mixed in compacted soil, he found the paper loosens the soil and improves
yields of corn, soybeans, and cotton. He has worked with farmers in Texas,
using large pellets as a surface mulch to keep bare soil from blowing away.
[See Trash to Treasure: Recycling Waste Paper, Agricultural
Research, October 1993, pp. 18-21.]
Adamoli makes the pellets in various sizes. But to fit home fertilizer
dispensers, he makes them the size of a fertilizer pellet: 3/16 inch diameter
by 1 inch long. He also plans to break up the pellets for use as livestock
bedding. He and Edwards are testing the bedding in five poultry houses in
The paper pellets form a soft bedding that is easier on a chick's tender
breast and feet than aged sawdust or other bedding material. Farmers report
they like the bedding better and that it does a better job of absorbing urine
and ammonia fumes.
These pellets fluff up when they get wet and absorb 4 to 5 times their
weight in water, Edwards says.
Tascon could contract with poultry houses to sell them fresh bedding and
later buy it back, used, with manure applied by the chickens. Tascon is looking
at making the paper-manure pellets into a potting mix and peat pots
for transplants. Edwards and Tascon personnel are now testing the potting mix
on greenhouse snapdragons, impatiens, pansies, and field ornamentals.
The manure, a nitrogen source, would help the paper waste decompose and turn
into compost. Lawn clippings and other yard and food wastes are candidate
nitrogen sources for decomposition, Edwards says.
However it is applied, the paper-manure mix improves soil quality at least
as much as manure alone, with less of an accompanying risk of nitrate/nitrogen
leaching from the manure to groundwater.
And Edwards experiments are increasingly convincing him that something
in waste paper has herbicidal qualities, controlling weeds such as crabgrass
better than commercial herbicides. That makes the paper peat pots especially
appealing to the horticultural industry. For if the herbicide could be
incorporated into the pot itself, the industry would save the waste and hazard
involved in trying to spray potted plants without hitting the spaces between
Edwards is also finding that the mixture shifts the balance of soil microbes
towards the types that increase plant health and yield and suppress many plant
disease-causing organisms. By Don Comis, ARS.
Fruit Laboratory, 10300 Baltimore Ave., Beltsville, MD 20705-2350; phone
"Trash or Cash Commodity?" was published in the
issue of Agricultural Research magazine.