Farmers have been able to maintain high crop production levels with farming practices that use intensive tillage, monocolture or 2-year rotations, and high fertilizer and pesticide inputs. However, such farming practices may result in soil erosion, reduced soil organic matter, deteriorating soil structure, reduced water infiltration, increased compaction, weed infestations, and severe plant pathogen problems.

Grain after grain, without special protection is more vulnerable to soil erosion than it would be in legume-based cropping systems. The increased soil erosion resulting from widespread use of monocultures has led to the development of conservation tillage techniques.

Farmers looking for new ways to reduce production costs. Throughout the United States, individual farmers have recognized that heavy purchases of off-farm inputs can put them in a less competitive economic position. For instance the greatest energy requirement for no-till corn production is for N fertilizer, representing about two-thirds of the total fossil fuel energy required. Unfortunately, the rising costs of synthetic chemicals has spurred a need to use these inputs more efficiently, or find substitutes, to ensure that US agriculture remains competitive in overseas markets. Farmers can use legumes in crop rotations with grains, as green manure for grains as winter cover, as an intercrop, as a trap crop, and as a renovator for unproductive pastures and range.

Many of the spring seeded early crops are developing quickly and some of the winter wheat will be harvested in the next few weeks. Spring wheat will follow shortly after that. The relative early harvest this year will provide some opportunities to seed a cover crop, anticipating that there will be some rain events in the coming weeks.

Legumes in rotations will fix nitrogen from the atmosphere into the soil. The amount of nitrogen fixed depends on the legume and the management system. Dry matter accumulation for well-adapted legumes seeded in the spring can range as high as 4 tons/acre, but more commonly ranges from 2 to 3 tons/acre.

Inclusion of forage or grain legumes in cropping systems often has a beneficial effect on the growth or yield of succeeding crops by providing N and through such non-N effects as reduced soil erosion; control of weeds, insects, or pathogens; or improved soil structure and soil moisture.