Broiler phosphorus intake versus broiler phosphorus output in the United States: nutrition or soil science?

Abstract

Phosphorus (P) is receiving considerable attention with regard to poultry litter in the United States. Litter, a combination of bedding material and excreta, contains valuable nutrients and has been historically applied as fertilizer on pasture and row crop lands. Compared to commercial fertilizers, broiler litter has a low nitrogen to phosphorus ratio. Poultry litter application rates have been based on the nitrogen needs of crops resulting in a gradual build-up of P in the soil. Phosphorus runoff into nearby water bodies can be detrimental to aquatic life. Proper management of litter is critical to maintaining the farmer's environmental stewardship. Many researchers are investigating best management practices to alleviate potential problems related to over application of P. However, gaps exist among the researchers due to their specialty and training.Communication across groups (nutritionists verses soil scientists) is the key for making progress. For example, the agronomist's plan for utilization of litter should coincide with the nutritionist's specifications for P requirements. This article identifies some of the more commonly used terms that define the forms of P in an effort to unite the different perspectives. The purpose is to convey the complexity of the existing efforts for P analysis, identifying factors that influence changes in chemical forms such as dietary P level, P source and characteristics, the use of dietary phytase in rearing conditions, subsequent litter handling, and conditions of litter application. The end result should create a “cause and effect” type thinking among the groups working on the broiler industry P issues.