Grazing – legumes
Legumes are notable for their ability to fix nitrogen in the soil, reducing the need for the addition of nitrogen fertilizer. Planting legumes such as alfalfa, clover, peas or beans in managed pastures provides increased forage for cattle and other livestock, while also adding carbon to the soil.
The Numbers
Legumes could be planted in pastures across 72 million hectares globally, an area about twice the size of Japan.
Planting legumes in pastures could sequester up to 132 million tonnes of carbon dioxide equivalent per year (MtCO2e/year). That’s comparable to the emissions from 28 million passenger vehicles per year.
The Challenges
Compared to other grazing practices, planting legumes in pastures has a more limited geographic potential, because it only applies to planted pastures that have a relatively low abundance of legumes to start with. However, there are no major challenges to implementing more widespread planting of legumes in pastures.
Moving Forward
In quantifying the benefit of legumes in pastures, native prairies or areas where planted legumes might displace native plants were not included in the study. Yet in many areas, opportunity exists to seed planted pastures with legume species.
This is a low-cost pathway that is ready to implement immediately. In fact, many ranchers have already overseeded their pastures with legumes to improve forage and productivity.
Case study
Spotlight: Improving Pastures in Southern Australia
Legumes are critical to Australian pasture systems, providing feed quality for livestock and increasing pasture yields. Phosphorous is necessary to drive nitrogen fixation by legumes, but many Australian soils are low in phosphorous.
In an effort to improve the productivity and profitability of Australia’s southern pastures, the Australian government recently provided a research grant to Meat & Livestock Australia, a nonprofit organization that delivers research and development services to Australia’s red meat industry.
The project will explore the use and development of pasture legumes that have high yields at low levels of soil phosphorous. Such efforts will help maintain productive, profitable pastures while reducing the need for fertilizer.
Similar research is likely to drive the use of legumes in pastures. Planting legumes will be particularly important in areas with significant overgrazing, including Western Europe, Oceana, the Middle East and North Africa.
