Knife Aeration to Reduce Concentrations of Sex Hormones in Surface Runoff from Pastures Fertilized with Broiler Litter

Abstract

Broiler litter contains the naturally-excreted hormones testosterone and 17-β estradiol, which can contaminate surface runoff when litter is applied to pastures. This study was conducted to evaluate the effect of knife aeration of pastures receiving broiler litter on hormone concentrations in surface runoff. Six 0.8-ha paddocks on tall fescue and bermudagrass were fertilized with 5 Mg ha1 in March and November 2008, and in March 2009. Three paddocks were aerated immediately after application and three paddocks were left non-aerated as controls. Surface runoff samples were collected with automated samplers and analyzed for the sex hormones with GC/MS. Knife aeration reduced concentrations of hormones in surface runoff occurring soon after litter application and aeration. These results suggest that knife aeration may be a useful management practice to reduce contamination of surface waters with sex hormones derived from broiler litter.