Development, calibration and application of new analytical methodologies for measuring ammonia and nitrogen oxide emissions from fertilized soil

Abstract

Sugarcane plays a prominent role in Brazil's current economy and has growth projections for the coming years mainly due to the use of biofuel ethanol as an alternative energy source. However, a relevant problem regarding the production of ethanol refers to the possible massive increase in the emissions of reactive nitrogen compounds, such as NH3, NO and NO2 to the atmosphere, due to the use of nitrogen fertilizers in the cultivation process. These compounds may undergo transformations for other gaseous species, such as nitric acid (HNO3), photocatalyses the formation of tropospheric ozone, or even nucleate particles such as ammonium nitrate (NH4NO3) forming fine particulate matter, associated with respiratory health problems in humans. As emissions increase, the rates of deposition of these compounds to the surface also rise, causing a number of environmental problems, such as acidification of aquatic ecosystems, soil weathering and loss of biodiversity. Considering the scarcity of information on NO, NO2 and NH3 emissions from nitrogen fertilizers used in sugarcane crops and their impacts, in this project, passive and active samplers will be developed/adapted for the monitoring of these gases emitted in an agricultural site dedicated to the cultivation of the sugar cane in the Araraquara region during a complete cycle of cultivation of this culture. The climatic and crop management conditions will be evaluated and related to the measured emission flows. Finally, it is intended to estimate the contribution and the effect of these emissions of reactive gases and particles from the monitored agricultural area on the chemical composition of the local atmosphere and also on the dry and wet deposition of chemical species for soil and surface water. (AU)