Alfalfa farmers are on their second hay cutting in California’s Central Valley. Lush green fields are swathed with new generation rotary disk mowers that are nearly twice as fast as the conventional sickle mowers, cutting about 150 acres of alfalfa a day. Alfalfa hay fields are cut from four to ten times a season, averaging about seven tons per acre per year. It’s a profitable crop these days, with prices for high quality hay frequently reaching $250/ton.

But in addition to its over $1 billion value to the state of California, alfalfa provides a host of environmental benefits that are frequently overlooked. What are these benefits?

Benefits to the soil. In addition to being an important cash...