ABSTRACT
The annual production of manures from livestock on farms in the United States exceeds about 2.3 billion wet tons (over 350 million dry tons). The production of farm manures far exceeds that of sewage sludge (estimated to be about 26 billion dry tons annually) by a ratio of about 14 to 1 and is enough to provide nutrients to produce crops on 115 million acres of farmland if it were fully utilized. Most of the farm manure that is recovered for use in farming comes from livestock and poultry grown in confinement. However, about two-thirds of farm manures are excreted on pastures. Only a small fraction of the potential value of farm manures actually is realized, for much of the manure is wastefully and inefficiently handled. Handling of the large quantities of manure presents major problems to dairy, livestock, and poultry farmers in the United States. These farmers often do not have adequate areas of land on which manures can be applied. In some cases, land is overloaded with manures, but more often, wasteful methods of handling lead to large losses of nutrients and organic matter from manures.
