Aerobic microbial decomposition and transformation of organic materials. It is usually achieved by regular turning and aeration of a stored organic product in piles with a geometry that can favour aeration. With this transformation, the chemical composition, particularly the C to N ratio comes closer to values needed for the net release of N once the product is land-applied. Concomitantly, the product may become less bulky due to the loss of water and also more manageable due to homogenisation. Additional benefits of composting involve the decrease in the initial phyto-toxicity of organic materials used, reduction in weed and pest infestation, and potential biocontrol effects.