Alfalfa is the most diverse, mostly wild herbaceous plants. Alfalfa produced in China, there are three main: the first is alfalfa, stem length of about six inches, upright, purple flowers pods turn curved. The second is yellow alfalfa, the stem is not upright, prostrate on the ground, yellow flowers, leaf-shaped like a sickle. These two are produced in the northern provinces. The third is wild alfalfa, commonly known as grass head, also known as golden cauliflower, stems lying on the ground, each fine stems, on the three leaflets, China's lower reaches of the Yangtze River, there are wild and planted as food. Generally, horses eat alfalfa. Alfalfa is a perennial leguminous forage grass and the most planted forage species in the country and the world. Because of its wide adaptability, high yield, good quality and other advantages, known as the "king of pasture", the name. Alfalfa stem and leaves are tender and fresh, regardless of green fodder, silage, modulation of green hay, processing of grass powder, used in combination feed or mixed feed, all kinds of livestock and poultry are the most preferred food, but also pig and poultry industry preferred green fodder. Alfalfa is native to Iran, is the most widely distributed cultivated pasture grass in the world, has been cultivated in China for more than two thousand years, the main production areas in the northwest, north China, northeast, Jiangsu and Huaihe River Basin, according to incomplete statistics, the world's alfalfa planting area of about 12,333,333 hectares. Alfalfa has a strong resistance to adversity and a wide range of adaptability, and it can grow in many types of climatic and soil environments. It prefers dry, warm, sunny and less rainy climate and high, dry, loose, well-drained and calcium-rich soil. The optimum temperature is 25 to 30 ℃; annual rainfall of 400 to 800 millimeters of good growth, cross 1000 millimeters will grow poorly. Annual rainfall of 400 millimeters or less, need to have irrigation conditions to grow vigorously. Summer rainy hot and humid weather is the most unfavorable. Alfalfa has a high transpiration coefficient and requires a lot of water for growth. Each composition of 1 gram of dry matter requires about 800 grams of water, but the most taboo water, if continuous flooding 1 ~ 2 days will be a large number of death. The life span of alfalfa is generally 5-10 years, in the annual rainfall of 250-800 millimeters, frost-free period of 100 days or more can be planted in the region. Neutral soil is preferred. pH 6-7.5 is preferred, 6.7-7.0 is best. Adult plants up to 1-1.5 meters high.