Nitrogen atmospheric deposition driven by seasonal processes in a Brazilian region with agricultural background

Abstract

Understanding the seasonal patterns and in uencing factors of nitrogen atmospheric deposition is essential to evaluate human impacts on the air quality and nitrogen biogeochemical cycle. However, evaluation of the nitrogen deposition ux, especially in South America agricultural regions, has not been fully investigated. In this paper, we quanti ed the atmospheric wet deposition uxes of total dissolved nitrogen (TDN), dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN), in a region with agricultural and livestock predominance in the Southern Minas Gerais region, Brazil, from May 2018 to April 2019. Deposition uxes of nitrogen species in the wet season (October -March) were on average 4.8 fold higher than dry season, which revealed signi cant seasonal variations driven largely by the seasonality of rainfall and agricultural operations. We also found high NO 3 − /NH 4 + ratios (average = 8.25), with higher values in dry season (NO 3 − /NH 4 + = 12.8) in comparison with wet season (NO 3 − /NH 4 + = 4.48), which revealed a higher relative contribution of NO x emissions from tra c sources in dry season. We also estimated the in uence of atmospheric deposition of inorganic nitrogen (N-DIN) on environmental ecosystems, being 2.01 kgNha − 1 yr − 1 with potential risk of acidi cation and eutrophication of 30%.Therefore, attention should be paid to the role of wet atmospheric deposition of nitrogen as a source of nitrogen environmental pollution in agricultural regions.