Coal Burning Byproduct Gives Ol’ Bossy a Leg Up on Mud

Flyash could offer dairy farmers a low-cost material for paving feedlot areas where deep mud can mire hefty cows and sap energy for producing milk. That’s the conclusion of Agricultural Research Service and collaborating scientists who studied the ash’s safety and durability. ARS is the U.S. Department of Agriculture’s chief research agency.

A byproduct of burning coal to generate electricity, flyash is normally trucked off to landfills at a cost to electric utility companies. About 32 percent of the 60 million-plus tons generated annually is used for construction and other applications, such as neutralizing acidic soils in crop fields.

Now it’s also available to dairy farmers in parts of New York and California as a cheap, barnyard paving resource. It dries just as hard as concrete, but costs $6 per square yard versus $75.

Studies by ARS soil scientist Bill Stout, geologist Tom Nicheson and two commercial collaborators--Air Products and Chemicals’ Gerry Thompson, and Black Rivers Co-Gen Partners’ Paul Cunningham--helped expedite regulatory approval from the two states.

One study, conducted in 1995-96 on a Harrisburg, Pa., dairy farm, examined the environmental impact of spreading 33 tons of recycled flyash onto a 900-square-foot feedlot. Another feedlot was left bare.

Lab analysis revealed some leaching of elements like calcium and heavy metals beneath the ash. But the levels were well within EPA limits, according to Stout at ARS’ Pasture Systems and Watershed Management Research Lab in University Park, Pa.

Another benefit of paving, besides keeping cows above the mud: better containment of nutrient-rich manure, which can otherwise get tramped into soggy soils. On some San Joaquin Valley, Calif., dairy farms, flyash paving has helped curb hairy footwort, a viral disease, and mastitis, a costly udder infection.

A more detailed story is in Agricultural Researchmagazine’s January issue, and on the Web at:

http://www.ars.usda.gov/is/AR/archive/jan99/pave0199.htm

Scientific contact: Bill Stout, ARS Pasture Systems and Watershed Management, University Park, Pa., phone (814) 863-0947, fax (814) 863-0935, [email protected], or Thomas Nickeson, (717) 724-5451.