SREL Reprint #2772

Distribution and Bioavailability of Trace Elements in Livestock and Poultry Manure By-Products

Nanthi S. Bolan1, Domy C. Adriano2, and Santiago Mahimairaja3

1Institute of Natural Resources, Massey University, Palmerston North, New Zealand
2Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina, USA
3Institute of Natural Resources, Massey University, Palmerston North, New Zealand

Abstract: Intensive confined livestock and poultry production systems generate large quantities of manure by-products, which have the potential for being recycled on arable land. Protecting the quality of the environment is a major consideration when developing management practices to effectively use manure by-products as a nutrient resource and soil conditioner in agricultural production system. To date, most of the environmental problems associated with land application of manure by-products have centered on the contamination of groundwater and/or surface water with two major nutrients, nitrogen (N) and phosphorus (P). With increasing use of trace elements (metal is substituted for trace elements for brevity throughout the text) as nutritional supplement in the form of feed additive in intensive animal production industries, manure application has emerged as an important source of certain metals (e.g., As, Cu, and Zn) input in soils. Unlike application of sewage sludge, where application rate is limited based on allowable metal loadings, regulations governing livestock and poultry manure by-products are generaly based on total N and/or P loading. Both sewage sludge and manure by-products are applied on land to primarily benefit from their N and/or P content but without regard to metals in the latter. The danger lies in accumulation of manure-borne metals since they vertually don't degrade with the potential of eventually becoming phytotoxic. In order to reduce the risk of offsite contamination, it is prudent to propose that land application guidelines for manure by-products be developed that consider their total composition rather than just only specific compenent (i.e. N and/or P). The present review aims to examine the impact of increased usage of certain metals, especially As, Cu, and Zn, in livestock and poultry production on the quality of manure by-products. The beneficial effects of these metals in manure addition to overcome the deficiency of these metals in soils and the detrimental effects of manure-borne metals on plant growth and microbial functions are also examined. The practical implications of manure-borne metals on environmental comtamination are discussed in relation to management guidelines for the safe and beneficial use of manure by-products in agricultural soils.

Key Words: animal manure, bioavailability, biotoxicity, manure, threshold level

SREL Reprint #2772

Bolan, N., D. Adriano, and S. Mahimairaja. 2004. Distribution and bioavailability of trace elements in livestock and poultry manure by-products. Critical Reviews in Environmental Science and Technology 34:291-338.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).