Day and night, a huge contraption prowls the grounds at Frank Volleman's dairy in Central Texas. It has a 3,000-gallon tank, a heavy-duty vacuum pump and hoses and, underneath, adjustable blades that scrape the surface as it passes along.
In function it is something like a Zamboni, but one that has crossed over to the dark side. This is no hockey rink, and it's not loose ice being scraped up. It's cow manure.
Lots of cow manure. A typical lactating Holstein produces about 150 pounds of waste - by weight, about two-thirds wet feces, one-third urine - each day. Mr. Volleman has 3,000 lactating Holsteins and another 1,000 that are temporarily "dry." Do the math: his Wildcat Dairy produces about 200 million pounds of manure every year.
Proper handling of this material is one of the most important tasks faced by a dairy operator, or by a cattle feedlot owner, hog producer or other farmer with large numbers of livestock. Manure has to be handled in an environmentally acceptable way and at an acceptable cost. In most cases, that means using it, fresh or composted, as fertilizer. "It's a great resource, if used properly," said Saqib Mukhtar, an associate professor of biological and agricultural engineering at Texas A & M University and an expert on what is politely called manure management.
But as the increasing incidence of environmental and health problems linked to agriculture makes clear, when manure is mismanaged the nutrients in it can foul streams, lakes and aquifers; the pathogens in it can contaminate food products; and the gases it produces, including ammonia, methane and bad-smelling volatile compounds, can upset neighbors and pollute the atmosphere.
Even with best practices, manure can cause environmental headaches. So researchers are working on ways to improve its handling, to modify the nutrients in it and to develop alternative uses.
Mr. Volleman, who came to Texas from his native Luxembourg 16 years ago, takes pride in his operation, which produces about 25,000 gallons of milk a day. "It's all about keeping it clean, keeping it comfortable and producing high quality milk," he said, adding that what is good for his cows is good for him. "They're writing my paycheck."
Down on the Farm, an Endless Cycle of Animal Waste
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Down on the Farm, an Endless Cycle of Waste
By Henry Fountain
NYT, December 28, 2009
Straight to the Source
