Preparation method of high-energy forage grass taking straw as raw material

The invention discloses a preparation method of high-energy forage grass taking straw as a raw material. According to the preparation method disclosed by the invention, twice pretreatment is carried out on crop straw, a supermolecular structure of microfiber is remarkably broken, and cell walls of all tissues are broken to the maximum, so that follow-up lignin removing is facilitated; twice steamexplosion treatment is carried out on the crop straw, so that the lignin removing ability is remarkably improved, the lignin removing rate of the crop straw is up to 95 percent or above, cellulose cells of the crop straw are torn, the cell walls are loosen, the whole structure of coarse fiber in the crop straw and the structure of a molecular chain are changed, and cellulose molecules are fractured, so that the high-energy forage grass is beneficial for being absorbed and digested by cattle and sheep; the crop straw is subjected to twice steam explosion treatment, and the digestibility of thecattle and sheep on the cr