Organic Fertility Management Methods for building fertility in the soil without using chemical fertilizers are well-established. Applying animal manure is one of the oldest agricultural practices known. Composting the manure before it is applied kills bacteria, reduces odor, and minimizes nitrate release. Other sources of organic nutrients are fish emulsions, natural phosphates, bone meal, cottonseed meal, and seaweed. Growing a legume in rotation with other crops is a very important fertility-building practice.
Legumes host rhizobial bacteria that form nodules on the plant roots.
A crop grown for the purpose of being plowed back in is called a green manure. Austrian winter pea is one legume that is being studied for use as a green manure in the Great Plains. The 1990 Farm Bill included legislation entitled the Organic Foods Production Act of 1990 that will eventually establish national standards for organic production. Though guidelines have not yet been issued, they are expected to be in place for 1997. Other certifying agencies are chapters or branches of larger organizations.