Semi-dry silage, also known as low-yield silage. It combines the advantages of hay and general silage: low water content, high dry matter content (about 1 times more than normal silage), less nutrient loss, reduced handling costs, and reduced management costs. Therefore, it has been widely used in foreign countries such as the United States, the former Soviet Union, Canada, and Japan. (A) The basic principle of semi-dry silage When the raw material is dried to reduce the moisture content to 40% to 50%, the plant cytoplasm reaches a water potential of -55.72 to -60.79 bar. In this state, certain microorganisms, such as spoilage organisms, and D The life activity of acid bacteria and even lactic acid bacteria is close to the physiological drought state, and their growth and reproduction are inhibited. Therefore, during silage, microbial fermentation is weak and the protein is not decomposed. Of course, there are also some microorganisms, such as molds, which have a strong ability to utilize the water in the nutrient matrix (water potential in the nutrient matrix is ​​as high as -253.29 to -303.95 bar to prevent the mold from using moisture and nutrients therein). However, under anaerobic conditions, it cannot move. Therefore, semi-dry silage still requires highly sealed anaerobic conditions. (II) Method for measuring and measuring water content of semi-dry silage 1. Preparation method of semi-dry silage After silage is harvested, it is rapidly air-dried in situ. When the moisture content reaches 45% to 55%, it is shortened, filled and simultaneously compacted. , seal, prevent air permeability. 2. The appropriate moisture content of the semi-dry silage can be determined by weighing it during the drying process. The weight R of the 100kg silage raw material after drying should be: R=100 where: R—weight per kg of silage material 100kg dried to the required moisture content (kg). W—initial moisture content (%) per 100 kg weight of the silage. X—Moisture content (%) required per 100kg weight of silage silage. For example, the harvested fresh grass has a water content of 80%, and the semi-dry silage requires a water content of 50%. Substituting the formula, R=100=40 (kg), weigh 100kg of freshly harvested alfalfa fresh grass and dry it. The weight is measured periodically. When the weight of the crucible falls to 40kg, the water content of the crucible at this time is 50%.