Environmental Effects of In-House Windrow Composting of Poultry Litter
K. Wagner, M. Brown, L. Gregory, D. Harmel, C. Coufal, T. Gentry
Land application to crop and pasture land is a commonly-applied and effective method of utilizing the resource value of poultry litter. In-house windrow composting of litter is an emerging management practice with the potential to mitigate water quality and nuisance odor concerns associated with land application, but few studies have demonstrated these effects. This project was designed to evaluate and demonstrate the effectiveness of in-house windrow composting to reduce litter bacteria concentrations, improve runoff water quality, and mitigate nuisance odors relative to untreated litter. Results related to bacterial reductions were not definitive due to extremely low Escherichia coli (E. coli) counts in untreated litter prior to performing in-house windrow composting. This is attributed to dry litter conditions. Low litter moisture and less than full heating of the windrowed litter likely led to few differences in litter properties or in runoff water quality being observed. In terms of nuisance odor, human monitors reported higher odorant concentrations from the in-house windrow composted litter site, but they noted that the untreated litter application site had a more offensive “manure” smell than the in-house windrow composted litter site. Analysis of sorbent tube air samples also produced inconclusive results related to odor mitigation. Alternatively, laboratory-based assessment demonstrated that the odor detection threshold was almost twice as high (odors were twice as strong) for untreated litter compared to in-house windrow composted litter. In spite of the low moisture content of litter in this project, in-house windrowing of litter prior to land application exhibits potential to be an effective litter management practice; especially reduction of nuisance odors in the subtropical to semi-arid climate of Central Texas. This potential benefit complements additional benefits such as reduction in food borne pathogens and poultry disease.