Legumes are members of the plant family, Fabaceae, and include common crops such as peas, soybeans, alfalfa, and clovers.
The Land Institute is developing human edible perennial grain legumes and perennial legume ground covers as nitrogen-fixing companions in polycultures with other perennial grains.
- Legumes produce highly nutritious, high-protein seeds for human and animal consumption and high-quality forage for livestock.
- Through a symbiotic relationship with rhizobia bacteria, legumes convert atmospheric nitrogen into plant useable forms through nitrogen fixation. Legume nitrogen fixation is a sustainable strategy for decreasing synthetic nitrogen fertilizer inputs for grain production. The Land Institute is currently experimenting with intercropping Kernza® with legumes to help provide nitrogen for the grain.
- A potential new use for perennial legumes is as a living mulch in annual, agroforestry, and perennial grain cropping systems where they have demonstrated effectiveness for suppressing weeds, reducing soil erosion and nitrate leaching, and providing nitrogen credits for companion cash crops.
- With more than 20,000 legume species in the world and only around 15 pulse (grain) and 40 forage legumes traded globally, there is great opportunity to develop new perennial grain and companion legume crops. We have identified a short list of candidates using ideas from the pipeline strategy for grain crop domestication and some of the legume specific criteria our program has developed.
At The Land Institute, we are working with legumes in two major ways.
Perennial Grain Legumes: Temperate adapted perennial grain legumes, though currently non-existent, would be uniquely situated as crop plants able to provide relief from reliance on synthetic nitrogen while supplying stable yields of highly nutritious seeds in low-input agricultural systems. We are currently evaluating some native perennials such as lupins and some non-natives (alfalfa, sainfoin, etc.) as possible new grain legumes.
Companion Legumes: We are also exploring various temperate-adapted wild and cultivated forage legumes as continuous living cover companion species (intercrops) with other Land Institute perennial grains. We are particularly interested in alfalfa, kura clover, and some Astragalus species that fit our criteria for perennial legumes: facilitate biological nitrogen fixation and nitrogen-transfer in perennial polyculture cropping systems.
Learn about other perennial crops under development at The Land Institute.
The first trials in spring 2017 explored alfalfa and lupin as a potential new grain legumes and kura clover as a perennial companion legume. Since then the team has continued to work closely with the Perennial Agriculture Project Global Inventory (PAPGI) team to identify other perennial legume candidates for domestication. Today the team is expanding breeding and agronomic research studying intermediate wheatgrass intercrops with legumes and studying sainfoin as a perennial grain legume candidate. We are working closely with the PAPGI team to identify promising perennial legume species and to develop criteria for evaluating their agronomic potential as perennial crop plants using the pipeline strategy for domestication as a guide.
- Expand agronomic knowledge about dual-purpose intermediate wheatgrass + legume intercropping systems (i.e. row spacing, harvest timing, nitrogen balance) that produce grain for humans and forage for livestock.
- Design breeding strategies for improving the compatibility of perennial legumes, specifically alfalfa and kura clover, in intercrops with intermediate wheatgrass.
- Develop a long-term, collaborative domestication strategy to improve sainfoin seed yield and nutritional quality through a combination of breeding, agronomy, food science, and commercialization efforts.
- North Carolina State University, Plants for Human Health Institute, Kannapolis, North Carolina
- Saint Louis University and Missouri Botanical Garden, St. Louis, Missouri
- University of Nebraska, Lincoln, Nebraska
- University of Wisconsin, Madison, Wisconsin
- University of Minnesota, St. Paul, Minnesota
- Cornell University, Ithaca, New York
- Makaneyyat Project, Ramallah, Palestine
- National Laboratory of Genomics for Biodiversity, LANGEBIO, Irapuato, Mexico
A Deeper Dive
A Closer Look at Nitrogen
Nitrogen is a key player in producing chlorophyll, the pigment that absorbs sunlight for basic photosynthesis needs. Legumes continue to supply approximately 13% of the annual global agricultural nitrogen requirements, with synthetic inorganic nitrogen fertilizers fulfilling the vast majority of the remaining nitrogen requirements.
Legumes symbiosis with root-nodule bacteria (rhizobia) enables them to supply more than 100 Tg of biologically-available nitrogen to natural and agroecosystems each year through biological nitrogen fixation (BNF). This process, BNF, has been called the most fundamental biological process on earth aside from photosynthesis because nitrogen is the critical limiting element for plant growth. Availability of sufficient nitrogen to crop plants is essential for producing high-quality, protein rich, plant-based foods, and the entire nutritional nitrogen requirement for humans is obtained directly or indirectly from plants. Increasing the use of legumes for BNF supports the idea of ecological intensification by using ecological processes rather than external inputs for crop production.
Related Scientific Publications
Perennial groundcovers: an emerging technology for soil conservation and the sustainable intensification of agriculture
Integrating perennial groundcovers (PGC) — sometimes referred to as living mulches or perennial cover crops — into annual cash-crop systems could address root causes of bare-soil practices that lead to…