Environmental Impacts and Services of Forages: A Scoresheet for California.

California forages are diverse systems, from rangeland to irrigated pasture, many types of cash hays, to corn and small grain silage.  Alfalfa remains California’s number one acreage crop, often worth over $1 billion/year.  It has survived economically in a region which include high value crops such as lettuce ($1.5 billion),  tomatoes ($1 billion), grapes ($2.7 billion), and almonds ($2.2 billion). This is largely due to the states expanded dairy industry which now produces more than 20% of the US milk supply, and is the number one agricultural industry in the state at over $5 billion/year.  Western states have grown from producing 15% of the nation’s milk supply in 1975 to 46% currently, with California the major player. Beef and horses are the other key forage consumers, with beef remaining in the top 5 agricultural commodities in the state.  Other forages such as corn silage and small grain forage have expanded in dairy regions, and extensive rangelands, miscellaneous hays and irrigated pasture remain important.   As farmers try to survive economic ups and downs,  issues related to water, the environment, and regulation have taken center stage.  The Endangered Species Act and water transfers to urban areas have impacted water allocations, and concerns about water quality due to off-site movement of pesticides from alfalfa and nitrate contamination of groundwater from dairy wastes have dominated headlines. Water for aquatic habitat (salmon runs and indicator species such as delta smelt and suckerfish) often conflict with agricultural uses, conflicts frequently decided by judges.  Recent data on air quality impacts from dairies and feedlots have implicated cows but also silages, particularly corn and small grain.  Impacts from rangeland include riparian impacts, and the possibility of biological contamination of surface water—factors which also may impact nearby high value vegetable production.  The water supply implications of forages are large, particularly in drought years.  On the positive side, there are a range of environmental services that the livestock-forage system provides.  California dairies absorb huge quantities of what would otherwise have little value, from fermentation by-products and bakery wastes to tomato pumice, cotton seed, and citrus pulp--wastes which would otherwise end up in landfills.  Rangeland systems control wildland vegetation, prone to fires.   Alfalfa provides a wide range of environmental services, saving energy from N2 fixation, absorbing nitrates from groundwater, recycling municipal wastewater, providing carbon sequestration, and preventing soil erosion.  Alfalfa is a significant insectary, providing beneficial insects to neighboring crops, as well as a rotation benefits to high value crops.  Alfalfa fields have been used as mitigation habitat for urban sprawl, and protecting threatened species such as the Swainson’s hawk.  Grain forages and pasture provide habitat for migratory waterfowl and other species.  The wildlife habitat value of alfalfa has been increasingly recognized, as more than a quarter of California’s wildlife uses alfalfa for cover, reproduction, or feeding.   While water supply and quality and air quality concerns for forage and livestock systems remain large challenges for the state,  a range of environmental services argue in favor of forages as an important component of sustainability for California’s complex cropping systems in the future.