Most plant species sown for pastures belong to one of two plant groups; the legumes and the grasses. Legumes are plants with flowers like the sweet pea and produce their seeds in pods. Compared to grasses which have long slender leaves, legumes have compound leaves with three or more broad, rounded leaflets. Most legumes have tap roots which are able to obtain water from deeper in the soil than the roots of grasses.
Legumes are a unique plant family – plants which house their seeds in double seamed pods (clovers, peas, beans, lentils, lupins, soybeans, peanuts etc.). Economically important legumes have a special relationship with soil bacteria which transform nitrogen from air into nitrogen that can be used by plants and animals. Pasture legumes and grain legumes (pulses) nourish the soil as well as the animals which eat them.
Legumes have long been recognized as a valuable component of wildlife habitat. Legumes are utilized by many different wildlife species and provide essential cover for different life stages of wildlife. Some legumes, such as partridge pea and lespedeza, are an important food source for upland birds. Not only do legumes directly benefit wildlife, but the indirect benefits are there as well. Legume's short and long range benefits to the soil are very important, considering that all living things are dependent on the fertility of the soil for their own well-being.
Nitrogen is needed by all plants for growth. Legumes living together withnitrogen-fixing bacteria, called rhizobia, have the ability to transform atmospheric nitrogen into nitrogen in the soil for the plants to use. Legumes alsoprovide organic matter to the soil as well as providing cover to reduce soil erosion.
There are a large number of legumes that are valuable to wildlife and these can be divided into those that are native to this country and those that are introduced.
Legumes are highly valued because they are rich in protein and yield well without being fertilized with nitrogen. This is because legumes are able to form a mutually beneficial relationship with Rhizobia bacteria. In this association, the bacteria, which live in nodules or swellings on the legume roots, are able to fix atmospheric nitrogen and make it available to their host plant.