Legumes are uses in pure stands (monocultures) and in mixtures with grasses.  Legumes may be harvested (mechanically or by grazing animals), left on the soil, or incorporated into the soil.  Cover crops, left on or tilled into the soil, are used to protect soil from erosion, improve tilth, and increase nitrogen available to subsequent crops.

Legumes generally do not require N fertilizer because of their symbiotic relationship with Rhizobium bacteria. The two organisms together extract atmospheric nitrogen and convert it to a plant-available form within root systems of legumes. Legumes, when properly inoculated, can fix significant amounts of nitrogen. The amount varies among species, sites, seasons and years and ranges from as little as 20 to more than 300 pounds N/acre.

It is possible to establish legumes without the N-fixing bacteria, but forage yield and quality will be similar to grasses. Nitrogen fertilizer must be applied for high yield and quality, and the economic advantage of using legumes is lost.

In fields where legumes have been used in the past, the Rhizobia may persist for several years. However, when initially establishing legumes, the proper type of bacteria (inoculant) must be introduced into the forage system. This is known as inoculation. Inoculation of seed should occur before planting and may be accomplished in several ways.

• A sticking agent may be applied to the seed, then adding peat-based inoculant. The sticking agent may be a commercial preparation sold by the inoculant manufacturer. Coating seed with a 10% sugar solution can also be effective.
• Some inoculants come with a clay that helps the bacteria adhere to seeds.
• Some seed vendors sell seed that is already inoculated.

Inoculants contain live bacteria and should be used prior to the expiration date shown on the container.  Preinoculanted seed should be sown before the expiration date shown on the inoculant tag on the seed bag.  Inoculated seed should not be stored in a location where the seed will be subjected to high temperatures for a lengthy period of time nor should the seed be mixed with fertilizer. Both practices can be lethal to the bacteria. Once a field has a successful stand of a legume species, bacteria may remain viable in the soil for two to five years. If present in sufficient quantities, a subsequent planting of the same legume may not require reinoculation. The most consistent method, however, is to inoculate legume seed with the proper Rhizobia each time the seed is planted regardless of history.