Recycling of organic wastes as a fertiliser is of present interest from the point of view of recycling and utilisation of renewable resources. It is a cheap way of waste disposal and offers agriculture organic matter to improve soil fertility and minerals at low prices. However, wastes from modem industries very often do not fit into a modem agriculture with high yields and sensitive crop rotations.
Contamination with heavy metals and other xenobiotic compounds makes landspreading of many waste undesirable and even unacceptable.
The most severe competitor for the industry producing chemical fertilisers is animal manure. Of old the natural alternative for chemical fertilisers.