Faculty Advisor

Liam Heneghan and Margaret Workman


In this microcosm study we examined the decomposition of horse manure in three substrates: potting soil, wood mulch, and sand. Microcosms consisted of a sample of horse manure placed in a small leachable chamber, containing one of the three substrates. Mulch promoted the greatest mass loss. Leachate collected by irrigating each microcosm with distilled water was used to germinate radish seeds. Only the leachate from microcosms in which manure decomposed in potting soil promoted greater radish radicle growth compared to the controls in which no manure was placed. The implications of these results for the design of a soil-based decomposing system – specifically “The BioShaft,” designed by Domenico D'Alessandro – are discussed.