Ammonia and greenhouse gases emissions from dairy cattle buildings
Résumé
Dairy cattle buildings represent a large portion of agricultural emissions in Europe. French specificity resides in high proportions of dairy buildings including straw- based deep litter. Because little is known about emissions from these systems, the aim of our experiment was to compare gas emissions from two contrasted manure managements in controlled conditions: a tie-stall (TS) producing slurry and a straw-based deep litter (DL) producing farmyard manure. Two groups of three dairy cattle were offered both treatments in a Latin-square design during two periods of six weeks. Mean daily emissions were 78 %, 33 %, 25 % and 85 % higher
for DL compared to TS, respectively, for C-CO2, C-CH4, N-NH3 and N-N2O. These emissions were high compared to the literature, which could be partly due to overestimation of ventilation rates and/or polluted air entering the rooms through gutters. CH4 and N2O emissions from DL increased throughout accumulation time
because of anaerobic conditions. At the end of the experiment, without animals and new fresh manure input, emissions from the litter alone rapidly decreased. These results contribute to a better understanding of emissions from two contrasted housing systems representative of French conditions.