Phosphorus status of soils from the poultry zone in Puerto Rico

Abstract

The poultry industry is the economic backbone of the south central region of Puerto Rico. However, as in other poultry production regions in the U.S., concern has risen regarding its potentially damaging impact on the environment. Eutrophication of rivers and lakes, induced by excessive nutrient runoff, has forced regulatory agencies to closely evaluate manure disposal practices. Thus, the need is critical for environmentally sound management practices in poultry producing areas. The impact of years of manure applications on the nutritional status of soils was ascertained by evaluating a number of samples from nine poultry farms of Puerto Rico. The farms were selected among those with the highest bird populations. Sixty-seven percent of the samples analyzed contained phosphorus levels (Olsen) in excess of what is considered adequate to support crop growth. Fifty-six percent of these exceeded levels considered by some states as critical for water quality purposes. Measured levels ranged from undetectable values up to 900 mg/kg P.  A diagnostic tool known as the P index was used in an effort to identify areas of concern. According to this criterion, all farms studied had zones where nutrient runoff could threaten the quality of the surrounding water bodies.