Auteur: Velarde-Guillén J., Jiménez-Calderón J.D., Martínez-Fernández A. and Vicente F.
Jaar van uitgifte: 2015
The emission of methane by dairy cows, as enteric and manure fermentation, is the main source of greenhouse gas (GHG) emission in the dairy sector. The second most important GHG is the N2O emission as a result of nitrogen addition to the soil. An empirical model was used to predict the methane production by dairy cows feeding on two diets based on maize silage grown with organic (MSF) or conventional (ChF) fertilization (IPCC Tier 2) and the emission of N2O by both types of fertilization (IPCC Tier 1). The results were converted to carbon dioxide equivalent (CO2eq) using the Global Warming Potential of 25 and 296 for CH4 and N2O respectively. More than 70% of GHG emissions were due to enteric fermentation. Milk production did not show differences between treatments; however, a 10% higher production of CO2eq kg‑1 of milk was observed in ChF than MSF. The difference observed was due to the diet and not to the type of fertilization, because there were no differences between both soil managements. The results demonstrate that it is possible to reduce GHG emissions with the use of manure and slurry as fertilizers, without affecting milk production.