Direct and Residual Effects of Land-Applied Sweet Corn Processing Wastes on Nitrate Loss to Groundwater

Introduction: Production of sweet corn for processing in the Midwest is concentrated in Wisconsin, Minnesota, and Illinois with these three states accounting for over 60% of the 1991 national production of about 3.3 million tons. The economic contributions of this industry benefits urban and agricultural communities throughout the region. A major problem facing the sweet corn industry is the management of waste materials in a manner consistent with sustained profitably and environmental protection. The residues generated in sweet corn processing are bulky, heavy, expensive to handle, and cause environmental problems unless they are properly managed. Approximately two-thirds of the weight of harvested corn entering a processing plant must be removed as a waste material. This material consists mainly of husks, cobs, and other plant residues generated in canned or frozen sweet corn processing. Based on 1991 Wisconsin, Minnesota, and Illinois sweet corn production, approximately 1.3 million tons of waste materials must be managed annually. Traditionally, much of this residue has been stored in silage stacks and distributed to farmers during the winter months as livestock feed. For various reasons including reduced demand for sweet corn silage, seepage of acidic high BOD effluent from the stacks, odors, and regulatory actions against processing companies regarding surface water contamination, there is increasing interest in returning the residue to agricultural land immediately after processing. Continuation of the traditional stacking process now requires increasingly complex and expensive effluent containment and monitoring facilities. Very little information is currently available to determine appropriate land application rates for sweet corn processing residues or to indicate the environmental and agronomic effects of various residue application strategies.