Pig manure has sufficient amount of nutrients, especially N and P, which are the main limiting nutrients in majority of soil for crop production. However, long-term manure application to agriculture lands will lead to N and P accumulation in soils and an acceleration of soluble N and P transfer into water bodies via runoff (Huang et al. 2011; Li Q et al.
2012). To address this problem, strategies such as composting has been adopted in many countries.
During composting, labile organic compounds are stabilized and converted into products that could be used as organic fertilizer and soil conditioner.