The Poultry Industry is the economic backbone of the south-central region of Puerto Rico. However, as in other poultry production regions, concern has risen regarding its potentially damaging impact on the environment. Eutrophication of rivers and lakes, induced by excessive soil nutrient runoff, has forced regulatory agencies to closely evaluate manure disposal practices. To ascertain the impact of years of manure applications on the nutritional status of soils, a number of samples from 9 farms of the poultry zone of Puerto Rico were evaluated. The farms were selected among those with the highest bird population and represent sites differing widely in ecosystem composition. Available phosphorus (P) was determined (Olsen method) in those samples. Sixty six percent of the samples analyzed contained Ρ levels in excess of what is considered adequate to support crop growth. Measured levels ranged from undetectable values up to 900 mg/Kg P. The Ρ index, was employed in an effort to identify areas of concern. All farms studied had zones where nutrient runoff could constitute a threat to the quality of the surrounding water bodies.