ABSTRACT
Agricultural residues are produced in plentiful. Approximately, one kg of residue is produced for each kilogram of grains harvested (Fahey et al., 1991). This ratio of grain/residue translates into an excess of 40 billion ton of crop residue produced each year in the USA and 33 billion ton in Europe and the former Soviet Union (Agricultural Statistics, 1988). Com (Zea mays L.) stover, wheat (Triticum aestivum L.) straw and soybean (Glycine max L.) residues account for more than 75% of the total U.S. farm residues. The annual crops of com, wheat, and soybean produce about 16, 10, and 10 billion ton of residues, respectively, and most of this material is left in the field after grain harvest. In developing countries, these residues are used as a major source of cattle feed. In developed countries, these agricultural residues are not allowed to use as cattle feed because of the presence of various pesticide, herbicide, and insecticide residue. Management of post-harvest residue is a major problem in the USA. Farmers have to manage the residue efficiently in time for subsequent year's crop and also economically to save cost. Farmers in United States usually bum the residues after harvest. Fall is the burning season in the wheat fields of Washington State. To prepare for planting in 1998, farmers burned about 229,000 acres of wheat stubble, an increase over recent years (Tenenbaum, 2000). The fires are used to help control crop diseases and to clear fields before using a relatively new farming technique called minimum tillage, which reduces soil erosion but requires machinery that can get clogged by heavy stubble. Nationally, fires are also used to clear
stubble from grass seed fields in Idaho, rice fields in California, cornfields in Iowa, Illinois, and Nebraska, and sugarcane fields in Florida, and Louisiana.
