Storage conditions and animal source influence the dominant bacterial community composition in animal manure

The aim of this study was to determine the impact of storage, animal diet, and animal source on the bacterial community composition of manure. The differences among bacterial community structures in fresh manure from cows on two different diets, cow manure stored in a deep pit for about one month, and fresh pig manure were compared. A molecular approach consisting of terminal restriction fragment length polymorphism (T-RFLP), in combination with sequence information from clone libraries, facilitated the identification of specific dominant bacterial populations that varied significantly among manures from different sources and treatments. One such population, represented by TRF 157, the most dominant peak of the bacterial community from stored manure, was identified as a Spirochaeta sp. Interestingly, this peak was absent in the fresh manure communities. The prevailing species in the fresh manure bacterial communities were distinct from those in manure from the storage pit, indicating a major shift in bacterial community composition induced by storage conditions. Moreover, distinct differences in bacterial communities were observed among animal source, but not animal feed. Manure storage is consequently an important parameter to consider when handling fertilizers, in order to obtain an optimal soil microbial ecosystem functioning.