Metal Distribution and Sorption on Soil Aggregate Fractions from a Poultry Litter Applied Soil.

Understanding the distribution and factors affecting sorption of metals on to soil aggregate fractions in manure amended soils is important in evaluating the risk of metal run-off and leaching in agricultural soils. Metals bound to fine soil fractions is believed to have some impacts on water quality since the fine soil fraction is preferentially transported to surface water through run-off and wind erosion. Long-term application of poultry litter is expected to result in build up of certain trace and toxic heavy metals in agricultural soils. We have investigated the metal distribution in surface soil aggregate fractions from a long-term poultry litter applied Alabama Hartsells soil utilizing a sequential metal fractionation process. Some variations in metal distribution were observed in different size aggregate fractions. In addition, potential factors affecting Pb accumulation in fine soil particles in this soil was investigated using sorption experiments. This study indicates that Pb sorption onto fine soil particles may depend on particle size and amount of phosphate present on the surface.