More on Forage Crops: Grasses and Legumes What are legumes? Grain legumes/pulse crops are members of family Leguminoseae (pea and bean family). Growth is indeterminate (will flower until a stress [drought/frost/desiccation] stops growth). Clover, alfalfa and trefoil are legumes commonly seeded for reasons other than for seeds. In the graphic, a farmer is mowing a crop of alfalfa which he will leave to dry in the field before bailing. Legumes are a source of protein (feed) and nitrogen (soil fertility). Nitrogen (N) fixation is the most important feature of the legume family; forage legumes have the ability to fix nitrogen and return it to the soil. They are used in various crop rotations to maintain or to increase soil fertility. However, forage legumes need phosphorus for their own growth. Unless this is supplied, growth will decrease after two or three years if stands or fields are allowed to continue. They also need more moisture than grasses and their deep roots can deplete soil moisture quickly. Depletion of phosphorus and moisture around individual plants can thin out fields, so their uses as hay fields or pastures have time limits for efficient production. What are Grasses? Members of the grass family (Gramineae) produce large edible grains either for human or livestock consumption. The grain or seed is an edible fruit, consisting of the endosperm and the embryo (or germ). The endosperm is stored food and makes up the majority of the seed. Grains are rich in carbohydrates and contain substantial amounts of protein, as well as some fat and vitamins. Characteristics of Legumes and Grasses   Grasses Legumes leaf structure leaves arranged in two opposite rows on the stem with a single leaf at each joint alternate leaves (with stipule) on stem veins of leaf run parallel to the length of leaf veins branch off a central vein (middle of the leaf) from petiole leaves are long, narrow and can be flat, folded or rolled leaves are rounded or oval in shape and grouped in threes or arranged in series on either side of the petiole flower small, not usually bright color brightly colored with five sepals and five petals pollination via wind pollination via insects root structure fibrous root system tap root system can have underground stems (rhizomes) which allow plant to spread; if no rhizomes, are called bunch grasses may have rhizomes; inoculated seed can fix atmospheric nitrogen stem structure round, jointed (and sometimes hollow) stem (nodes and internodes) branched stems seed structure one cotyledon (monocotyledon)on seed two cotyledons (dicotyledon) seed head is usually a panicle or a spike seeds enclosed in pods other characteristics growing point at or below surface of soil; protected from grazing and can regrow; can begin growth early in the season higher protein content than grasses; some types can cause bloat in livestock