The benefits of organic matter to soils and crops are well established. However, few commercial growers add organic matter because of lack of availability and costs of handling. As the need to reduce the amount of wastes added to landfills increases, many municipalities and private companies are beginning to produce large amounts of compost from organic wastes from cities and farms. Availability of large amounts of locally made composts can enable even large growers to consider compost use as a part of their operations. Growers considering use of a particular compost should know something about its origin and production methods.
Feedstocks are the materials used to produce compost.
If all recyclable materials are removed, this feedstock contains mainly paper, fabrics, and food wastes. If it is not sorted, materials such as batteries, household chemicals, and construction debris can add heavy metals or other undesirable components. It is usually a good source of nitrogen and phosphorus. Biosolids from residential communities generally do not contain high levels of heavy metals. In areas where industry is contributing to the liquid waste stream, the metals may be a problem if pollution control laws are not enforced.