Hay quality is determined by what species are involved, the amount of leaf material in comparison to stem material, the time the forage was harvested, and the amount of weathering and handling the material has undergone. Ensilage is made by anaerobic fermentation of undried forage or the stalks of corn, sorghum, etc. Ensilage is usually rich in water. During fermentation, the acid content rises and preserves the plant material. Most of the cultivated forage crops are from Europe or Asia.
Most forage crops are perennials, but others are annuals.
Table lists some of the major forage grasses. Many of the same things apply to forage legumes. They also fix nitrogen. Table of forage legumes on pg. Many of the legume forage crops are also excellent bee plants as well.