Dairy farms produce a lot of milk, but they also produce a lot of manure – more than one hundred pounds per day per adult cow.

Many farms use large amounts of water to flush animal waste into “manure lagoons” where it breaks down without oxygen. The process releases methane, a potent global warming gas.

But there are ways to handle manure that greatly reduce its methane emissions.

Hughes: “I’ve always just been a scraper.”

Richard Hughes has owned a California dairy farm for decades. He says “dry scraping” involves using a tractor to simply push manure into a pit.

There, a structure called a weeping wall separates the liquid from the solid portions of the manure. The solids are stored dry and exposed to oxygen, which reduces methane emissions.

Though this process requires more labor than some other methods, Hughes says it requires less water and equipment maintenance. Plus, he ends up with nutrient-rich solid and liquid fertilizer that he uses on his fields.

Hughes: “If I don’t feed the soil, I don’t get good grass. If I don’t get good grass, I don’t get a lot of good amount of milk.”

So this relatively low-tech method can help the climate and keep a steady supply of milk flowing to market.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.

Daisy Simmons

Daisy Simmons is a freelance writer and editor with more than 15 years of experience in research-driven storytelling. In addition to contributing to Yale Climate Connections since early 2016, she also...