To reduce input costs in production agriculture, the practice
of using biosolids (treated sewage sludge) as a fertilizer in place
of mineral fertilizer (MF) for row crops and hay production has
become more common. Inappropriate use of MF or biosolids could,
however, have negative consequences. After these amendments
have been applied to land, sediment and nutrients (and bacteria
from biosolids) may be transported by rainfall runoff into surface
waters and contribute to nonpoint-source pollution.
Because of the variability in nutrient and bacteria levels among
manures and biosolids, their application is the subject of state and
federal regulation that aims to reduce risks to humans and the
environment from pathogens or excessive nutrient enrichment.