Approximately 65 million tons of perennial legume and grass hay crops are produced annually on about 30 million acres of the Great Plains in the United States and Canada. Within the United States, this includes 24 million tons of alfalfa hay produced on 9 million acres and 26 million tons of grass hay produced on the remaining 14 million acres. Variations in length of growing season, soil fertility, available water, and plant species produce wide variations in the yield of hay crops in the Great Plains. Depending on the year, an additional 15 to 20 million tons of hay baled from crop aftermath and annual grass crops could be added to the total. Sixty-five million tons of stacked hay would extend 27,357 miles (10 percent more than the distance around the equator), if packaged as large rectangular bales (1,800 pounds) and loaded on standard forty-eight-foot semitrailers at the rate of twenty-four bales per trailer!
Alfalfa hay production ranges from five harvests (10 tons per acre) on intensively managed, irrigated stands in the Southern Great Plains to only one harvest (1.5 tons per acre) from dryland stands in the higher elevations and latitudes of the north. An improved, cool season perennial grass such as Timothy may yield as much as 5 tons per acre from one harvest with intensive fertilization and irrigation in the northern latitudes. Average yield of native grass hay in the Central Great Plains, harvested once per season, is less than a ton per acre, but yield could be double or greater with above-average precipitation. In the Southern Plains, intensively managed stands of an improved, warm season perennial grass (i.e. Bermuda grass) may yield 5 to 7 tons per acre in one growing season. Because of its bulk and relative ubiquitous occurrence, most hay is consumed locally, except when adverse conditions, such as drought, necessitate shipments from surplus to deficit areas.
Alan Gray University of Wyoming
More, Kenneth, and Michael Collins, eds. Forages. Ames: Iowa State University Press, 1995.