Alfalfa is the fourth most widely grown crop in the United States, and a primary livestock feed source.
The estimated value of the domestic alfalfa grown annually is $11.7 billion from the 26 million acres of the crop grown each year. It is a highly nutritive feedstuff, typically offering 15-22% crude protein and significant amounts of 10 different vitamins. In addition to livestock and poultry, aquaculture has recently embraced alfalfa’s high nutrient content as a new source of fish food.
But USDA researchers say alfalfa’s greatest importance may not be the exceptional nutrition it provides, but its importance to the environment. Scientists at the Agricultural Research Service’s (ARS) Northern Great Plains Research Laboratory in Mandan, ND, have been studying the effects of alfalfa on carbon balance.
The multi-year study revealed that hayed alfalfa is more efficient than perennial grasses in taking up carbon under variable growing conditions.
“This attribute is important for producers, as it shows alfalfa can be a stable source of forage when conditions get tough,” said Mark Liebig, research soil scientist at the ARS lab. “The study also showed that alfalfa can limit the amount of carbon lost from cropland when included in rotation, so that’s good for the environment.”
The research team found alfalfa logged consistently higher levels of carbon flux compared to grassland. Carbon flux is the exchange of carbon between one place and another – in this case, between the atmosphere and either an alfalfa field or grass pasture.
“The greater carbon fluxes in the alfalfa field equated to more carbon being taken up from the atmosphere, essentially acting as a sink for carbon dioxide,” Liebig explained. “From a climate mitigation standpoint, that’s a good thing.”
