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Of Cows and Climate

CALS researchers are leading a far-reaching effort to gather information about greenhouse gases related to dairy—and to give farmers and other industry professionals the tools they need to reduce them.

Measuring the efficiency of protein use allows farmers to finely tune feed mixtures and reduce the amount of nitrogen in the manure. “If we get farmers to reduce the crude protein in the diet, we can reduce on a statewide average ammonia emissions by 30 percent and nitrous oxide emissions by 8 percent,” explains Powell. The tannins may further bind up the nitrogen, yielding even greater reductions, but those experiments are just starting.

Other research will assess how dietary changes affect milk production, the manure in the digester and soil resiliency. How does long-term management and crop rotation affect soil properties such as water retention and carbon storage? It was all complicated enough before adding greenhouse gases to the equation.

“We only control a handful of variables in any one study,” explains Ruark. His specialty is nitrogen cycling, but he’s spent much of the last year learning to speak the many different languages of this transdisciplinary project.

“I was trying to get engineers to talk to dairy nutritionists, and getting physicists to talk to education specialists, getting these diverse people in the same room. We don’t necessarily understand each other completely, but we’re moving forward,” Ruark says happily. “Breaking down the silos, having that direct interaction. It’s a unique experience for everybody involved.”