Composting usually plays an important role in organic fertilizer production, because it is a process of eliminating harmful substances in manure. In this process, it is necessary to control the moisture content at 40%-60%. Because when the water content of manure is higher than 60%, excessive water will affect the transport of oxygen and reduce the composting effect of manure. When the moisture content is lower than 40%, microorganism activity will decrease. So it cannot generate enough heat to kill harmful substances in animal manure. In general, the water content of fresh manure is 70%-90%, which is far higher than 60%. So before composting, you need to dry manure first.