菌膜发生的原因，一是袋栽平菇时袋料发菌不充分便进行覆土，致使菌丝在地表进行第二次营养生长而形成菌膜：二是栽培料的配方不合理，含氮量过多，碳氮比失调。三是所覆盖的土壤氮元素含量过高，或另外又添加了尿素。四是覆土土质粘重、板结。五是出菇期温度过高，温差小，或 The causes of bacterial membrane, first bagging mushrooms when the bags of germs will not cover the soil, resulting in the mycelium in the surface of the second vegetative growth and the formation of bacteria membrane: Second, unreasonable cultivation of the formula formulations, nitrogen Excessive amount of carbon and nitrogen imbalance. Third, the soil nitrogen content is too high, or in addition to add urea. Fourth, clay soil sticky, plate knot. Fifth, fruiting period temperature is too high, the temperature difference is small, or