Theme 33: Technology Transfer and Education
Description
Municipal biosolids (sewage sludge) are the by-products of wastewater treatment plants and their production, worldwide, has steadily increased over the past years. Florida is one of the fastest growing states in the USA. Biosolids are readily and increasingly available throughout the state. Pasture fertilization has been shown to increase biomass and quality of bahiagrass (Paspalum notatum Flugge) dramatically in Florida sandy soils. Nevertheless, with low cattle prices, ranchers are forced to reduce fertilizers inputs. Biosolids contain considerable amounts of nutrients, especially nitrogen (N), phosphorus (P), sulphur (S), calcium (Ca), and micronutrients, and are inexpensive when compared with commercial fertilizers. Nevertheless, the concern remains that metals contained in these residuals accumulate in the tissues, in levels that would result be harmful to animals consuming the forage. This study investigated effects of seven rates of municipal biosolids applied to bahiagrass pasture on trace metal concentration in the forage. Iron (Fe), copper (Cu), cadmium (Cd), lead (Pb), and nickel (Ni) concentrations were determined in the tissue sampled at various dates after initial biosolids application. Metal concentrations were increased with increasing rates of biosolids, especially with the highest rate, in the first harvest date, but decreased with successive harvests. By the fourth harvest, Cd, Pb and Ni were hardly detected in forage. The increases verified in plant metal contents were not substantial enough to yield concerns regarding animal consumption, even with the higher rates of biosolids.
Included in
Application of Municipal Biosolids to Bahiagrass Pasture: Trace Metals in Harvested Forage
Municipal biosolids (sewage sludge) are the by-products of wastewater treatment plants and their production, worldwide, has steadily increased over the past years. Florida is one of the fastest growing states in the USA. Biosolids are readily and increasingly available throughout the state. Pasture fertilization has been shown to increase biomass and quality of bahiagrass (Paspalum notatum Flugge) dramatically in Florida sandy soils. Nevertheless, with low cattle prices, ranchers are forced to reduce fertilizers inputs. Biosolids contain considerable amounts of nutrients, especially nitrogen (N), phosphorus (P), sulphur (S), calcium (Ca), and micronutrients, and are inexpensive when compared with commercial fertilizers. Nevertheless, the concern remains that metals contained in these residuals accumulate in the tissues, in levels that would result be harmful to animals consuming the forage. This study investigated effects of seven rates of municipal biosolids applied to bahiagrass pasture on trace metal concentration in the forage. Iron (Fe), copper (Cu), cadmium (Cd), lead (Pb), and nickel (Ni) concentrations were determined in the tissue sampled at various dates after initial biosolids application. Metal concentrations were increased with increasing rates of biosolids, especially with the highest rate, in the first harvest date, but decreased with successive harvests. By the fourth harvest, Cd, Pb and Ni were hardly detected in forage. The increases verified in plant metal contents were not substantial enough to yield concerns regarding animal consumption, even with the higher rates of biosolids.
