AGRICULTURAL SOLID WASTES

The U. S. Department of Agriculture’s 1938 Yearbook of Agriculture contains these statements: “One billion tons of manure, the annual product of livestock on American farms, is capable of producing $3,000,000,000 worth of increase in crops. The potential value of this agricultural resource is three times that of the nation’s wheat crop and equivalent to $440 for each of the country’s 6,800,000 farm operators.” Since then, animal wastes have been transformed from a definite asset to a liability. By 1965, the disposal of animal excreta had become a serious problem (American Chemical Society, 1969). At any given time, an estimated 11 million cattle were on feedlots, the capacities of which ranged from 1000 to 50,000 head.

The problem has become much more severe today. Application of animal wastes to land is one of the most economical choices for disposal as well as providing fertilizing benefits. However, the utilization of livestock and poultry manures as waste biomass resources for energy applications could help mitigate pollution and at the same time open new markets. This possibility is examined here. Agricultural crop residues are included in the assessment.