Methane emission factors from cattle manure in Mexico

Factors responsible for methane emission from cattle manure representing di verse climates, systems and functions of cattle production are presented. T hese factors were obtained by means of an experimental methodology develope d for this project. It was considered that the temperature, moisture, handl ing of manure and the animals' feed ration affect methane production. Dryin g conditions and fermentation of manure in cool, temperate and warm climate s were simulated in the laboratory. Cattle manure was obtained from animals in intensive, semi-intensive and extensive production systems; for dairy, non-dairy and double purpose cattle production functions. Also handling of manure in dry lot, pasture and solid storage was considered. Results sugges t that the dominant factor in methane emissions is the feed ration, followe d by fermentation temperature and the excreta moisture content. The emissio n factors obtained in this work are at least a factor of five smaller than those proposed in the revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories for countries like Mexico. (C) 2001 Elsevier Science Ltd. A ll rights reserved.