If loose grain is moist, the air in the gap under the most surface layer of loose grain is hot and humid, and the cooler fresh air outside the cabin enters the cabin, then the water vapor on the surface layer of loose grain condenses into water drops, and the surface layer of loose grain will become moldy, or even agglomerate into layers. This layer will further block the heat and moisture emission of the lower valley, so ventilation will not improve the situation, and may be harmful.
But it is not to say that ventilation should never be done. When the temperature inside the cabin is more than 2.5℃ higher than that outside the cabin and the relative humidity inside the cabin is much higher than that outside the cabin, ventilation is possible under meteorological permission. The best step is to ventilate slowly first, such as opening the entrance cover and entrance door of the cargo compartment and adopting natural ventilation, and then accelerate the ventilation.