Intensive livestock production generates large quantities
of manure, most of which is applied to limited areas of
land in close proximity to the manure source. Continuous
heavy manuring may pose environmental problems due
to heavy metal accumulation in the soil (Wadman et al.,
1987). Excess application of manure to the soil is one
of the greatest concerns regarding livestock production
(Abdel-Shafy, 1996), since it creates an accumulation of
nutrients, such as phosphorus, zinc and copper, which can
potentially enrich water sources during run-off or through
leaching into ground-water supplies