Jun. 3, 2013
By: Rachael Freeman Long and Daniel H Putnam; UC Davis
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 10 times a season, averaging about 7 tons per acre per year. It’s a profitable crop these days, with prices for high quality hay frequently reaching $250 per 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 crop for growers, alfalfa is good for our soil. Alfalfa is a perennial flowering plant in the pea family that is planted in the fall and remains in a field for four to six years. The crop requires few inputs, as the plants fix their own nitrogen from Rhizobia bacteria colonizing the roots, with 90 percent coming from atmospheric nitrogen. Free fertilizer from nature! The long alfalfa stand life also gives the soil a chance to rest from frequent field crop rotations, helps provide nitrogen for subsequent crops and improves soil tilth.
Alfalfa is an insectary. Alfalfa also hosts a diversity of insects, many of which are beneficial, such as lady beetles and parasitoid wasps. These in turn help control other types of insect and mite pests in alfalfa and other crops, potentially saving growers money for pest control. One option to further manage crop pests is by strip cutting the alfalfa, a process that leaves some uncut areas during harvest so that alfalfa serves as a trap crop, holding pests that could infest neighboring crops.
Wildlife loves alfalfa. With nearly a million acres of alfalfa grown in California, alfalfa also serves as an important feeding and resting area for many species of birds, such as curlews, white-faced ibis, and Swainson’s hawks, all species of conservation concern. With historic wetlands significantly reduced in our state, alfalfa is second only to rice in terms of its value in providing habitat for wildlife, according to wildlife specialists. Growers often rely on birds foraging in alfalfa to help control rodent pests such as the gophers and voles that thrive in alfalfa fields. As you drive by alfalfa stands, look for flocks of birds that follow the irrigation water, picking off rodents, insects, and earthworms that are pushed out of the soil when fields are flooded.
Alfalfa-ice cream in the making! Markets for alfalfa primarily include the dairy industry, with alfalfa being an important part of a cow’s feed ration, as it provides high protein and energy for high milk production. This is economically important (the dairy industry is worth $7 billion per year) but also important for human nutrition. A California alfalfa field can produce 2,400 gallons of milk per acre. So the next time you have pizza (with cheese), milk on your cereal, or ice cream, thank alfalfa.
Other markets for alfalfa include livestock, such as horses, sheep, goats and beef cows. Most of our hay stays in state, but other significant markets include China, Japan and Saudi Arabia. Alfalfa seed is also an important source of honey and feeding areas for bees.
When you smell the fragrance of newly mown hay, thank the alfalfa grower and the “Queen of Forages” which helps produce milk right here in California. Watch the fields for bird activity and see if you can spot some Swainson’s hawks feeding on rodents and helping alfalfa growers with pest control, or curlews and egrets foraging for prey. But also be grateful for a host of important wildlife and environmental benefits to the landscape that alfalfa provides.
Rachael Freeman Long; County Director, Farm Advisor for Field Crops, Pest Management
Daniel H. Putnam; Extenson Specialist, Agronomist in the AES