Nitrogen production is the key benefit of growing legume cover crops. Legumes have a symbiotic relationship with rhizobia that take gaseous nitrogen from the air and feed this back to the plants; the reason why legume cover crops are said to “fix” a certain amount of nitrogen in the soil. This natural system is less expensive than the energy-intensive manufacturing and application of inorganic nitrogen fertilizers. Legumes are well-known for their superior quality as forage. Palatable and easily digestible, legumes provide higher levels of crude protein and are less fibrous than grasses resulting in faster digestion and increased intake of nutrients by both livestock and wildlife.

Brassicas represent a smaller group of broadleaf plants belonging to the mustard family. This group includes cabbage, collards, mustard, kale, radish, turnip, and rapeseed. While brassicas provide excellent disease suppression, they are not a mychorrizal fungi host and should be used in mixes with a grass specie. Brassicas are generally small-seeded and require a very low seeding rate.