Vongkhamchanh B, Inthapanya S and Preston T R 2015: Methane production in an in vitro rumen fermentation is reduced when the carbohydrate substrate is fresh rather than ensiled or dried cassava root, and when biochar is added to the substrate. Livestock Research for Rural Development. Volume 27, Article #208. Retrieved , from http://www.lrrd.org/lrrd27/10/bobb27208.html