AMMONIA EMISSIONS FROM THE AGRICULTURE SECTOR OF ARGENTINA IN A CONTEXT OF CHANGING TECHNOLOGIES AND PRACTICES

Abstract:

Agriculture is a key sector of the Argentinean economy, accounting for 6 to 8 5% of the GDP in the last ten years. Argentina switched in the 90´s from an articulated co-evolution between extensive livestock and crop farming, with annual rotation of crops and livestock, to intensive decoupled practices. Under these new production schemes, ecosystems were supplied with more nutrients, generating increasing levels of wastes. Other changes have also occurred, associated with the shift of the agricultural frontier and the consequent reduction in the cattle stock. In addition, changes related to climate through the strong increase in rainfall in the 80s and 90s in the west Pampas, helped to boost agricultural development. The agriculture sector accounts for practically all NH₃ emissions in Argentina, however no inventory has been thus far available. To bridge this gap and particularly to have accurate input information to run coupled atmospheric chemistry models for secondary inorganic aerosols, we estimated 2000-2012 NH₃ emissions, both at national and spatially disaggregated levels. Of particular interest for us was also temporal disaggregation as crops growing and temperature exhibit strong seasonal variability. As no NH₃ inventory was available we also estimated related N₂O emissions to verify our estimates with those of national GHG emission inventory (NEI). National NH₃ emissions in 2012 amounted to 309.9 Gg, use of fertilizers accounted for 43.6%, manure management 18,9%, manure in pasture 36,0% and agricultural waste burning 1.5%. Our N₂O estimates are in good agreement with the GHG-NEI. NH₃ estimates in the EDGAR database for 2008 are 84.0% higher than ours for this year, and exhibit more significant differences per category, namely 113,6% higher for use of fertilizers and about 500% higher for agricultural waste burning. Urea dominates national NH₃ emissions, accounting for 32,8% of the total and its use for wheat and corn crops dominates the trend.