Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/1997
Publication Date: N/A
Interpretive Summary: Poultry litter contains several hormones (chemicals manufactured by animals and that in very small quantities regulate critical body functions), including the estrogen 17beta-estradiol, the most potent of the estrogens and the hormone responsible for the development of the female reproductive tract and of female sex characteristics. Estradiol in runoff from pastures sreceiving applications of poultry litter may be detrimental to the health and reproductive capabilities of fish and other animals. This research evaluated the effectiveness of various grass filter (or buffer) lengths for reducing transport of this hormone in runoff. The study indicates that a fescue grass filter length of 3.1 m (20 ft) could reduce transport of estradiol by 79%. Filter lengths of 6.2 and 18.3 m (40 and 60 ft) reduced transport by 90 and 98%. These observations, together with other studies, illustrate the value of grass filter strips for minimizing the impacts of pasture-applied wastes on surface waters.
Technical Abstract: Discharge of hormones contained in poultry litter into the environment may disrupt the health and reproduction of fish and other animals. A runoff study was conducted to evaluate grass filter effectiveness in reducing transport of the estrogen hormone 17beta-estradiol in runoff from pasture-applied poultry litter. The study objectives were to determine the eeffects of source (litter-treated) length and grass filter length on runof concentrations and losses of 17beta-estradiol from poultry litter applied to fescue (Festuca arundinacea Schreber) plots. Litter was applied at 146.4 kg N ha**-1 (130.7 lb ac**-1) to the upslope 6.1, 12.2, and 18.3 m (20, 40, and 60 ft) of 24.4-m (80-ft) long grass strips. The corresponding grass filter lengths were 18.3, 12.2, and 6.1 m (60, 40, and 20 ft), respectively, with the downslope edge of source areas evaluated as a 0-m long filter. Simulated rain was applied at 50 mm h**-1 (2 in h**-1) to produce runoff samples for 17beta-estradiol anaylsis. Runoff concentrations and mass losses were not significantly affected by source length and averaged 3.5 ug L**-1 (ppb) and 1413.4 mg ha**-1 (0.02 oz ac**-1), respectively. Runoff concentrations were reduced by 58, 81, and 94% and mass losses by 79, 90, and 98% by filter lengths of 6.1, 12.2, and 18.3 m (20, 40, and 60 ft), respectively. The data from this research indicates that grass filter strips can effectively reduce runoff transport of 17beta-estradiol from fescue-applied poultry litter.