By Janet Raloff
From Minneapolis, at the Second International Conference on Pharmaceuticals and Endocrine Disrupting Chemicals in Water.
Livestock naturally excrete large amounts of estrogen and testosterone, hormones that can harm crops and wildlife when farmers use manure as fertilizer (SN: 7/15/95, p. 44). A study now shows that farmers can rid chicken manure of much of this unwanted hormonal baggage by composting the wastes.
Heldur Hakk of the Agriculture Department’s Biosciences Research Laboratory in Fargo, N.D., and his colleagues collected manure from egg-laying chickens and mixed it with hay, straw, decomposing leaves, and some starter compost. Then, they added water and heaped the mix atop impermeable pads in long compost piles. Periodically, they turned the compost to maximize the bacteria-driven degradation, which generates heat.