STABILIZING CATTLE FEEDLOT SOIL WITH FLUIDIZED-BED COMBUSTOR ASH

Many cattle feedlots are operated on bare soil because it is expensive to cover the entire lot with concrete. During heavy rainfalls, feedlo ts built on clay-rich soils often become muddy as their soils lose str ength. These soils cannot support the weight of animals or equipment. As a result, the animals' rate of gain suffers, and feedlot management becomes difficult. Fluidized Bed Combustor (FBC) ash from the Iowa St ate University Physical Plant was used to produce a significant increa se in soil strength on a cattle feedlot near Nevada, Iowa. FBC ash is the residue from burning high-sulfur coal in fluidized bed combustors. Limestone (calcium carbonate) enters the combustor with the coal as a sorbent to reduce sulfur dioxide emissions. FBC ash is considered a ' 'nuisance'' waste, and the cost for disposal exceeds US$20 per metric ton. Stabilizing cattle feedlot soil with FBC ash represents a recover y of resources because the ash, when combined with clay soil and water has cementious properties Research was conducted with three objective s: (1) to determine whether FBC ash can be used to increase the streng th of feedlot soil when applied at a level of quality control attainab le by using ordinary agricultural tillage equipment; (2) to compare fe edlot soil stabilized with FBC ash to non-stabilized feedlot soil in b oth laboratory and field tests; and (3) to develop a low-cost alternat ive to paving a feedlot with concrete. Field results from a feedlot tr eated with FBC ash show that soil strength was improved 200% to 300% w hen compared with an adjacent untreated feedlot.