2021 Volume 1 Issue 2 Pages 1-11
Development of locally-available microbial materials is a high-priority issue for future food production in sustainable agricultural management. In this study, we focused on the horticultural value of horse manure from retired racehorses reared at a local stable in Minami-soma City as a potential composting material applicable for sustainable agriculture in Fukushima Prefecture and performed a bench-top composting experiment. The maturation of the resulting compost was confirmed by the increase of nutritive elements including P, N and K as well as the final C/N ratio of 27.4, which is in the range of the ideal values of mature composts. Microbial composition before and after composting was investigated by 16S rRNA gene sequencing, which showed that the starting material (horse manure) was dominated by bacterial groups affiliated with obligate anaerobic bacterial taxa from equine cecal microbiota , while the mature compost was dominated by bacterial groups of many aerobic or facultative anaerobic taxa, which were likely to be involved in aerobic degradation of organic substrates during the ripening process, indicating that the microbial composition changed significantly during the ripening period. In addition, the germination rate and oxygen consumption after ripening met the generally approved standard, which emphasized that horse manure from retired racehorses can serve as a good microbial material for producing high-quality composts in a space- and time-efficient way compared to other livestock manures. By reference to these results, we plan to build a local platform to produce horse manure composts with scientifically proven values toward the practical implementation.
