Reactive nitrogen emissions from crop and livestock farming in India

The rapid increase in anthropogenic nitrogen emissions to the atmosphere is matter of concern for the environment, as these may lead to photochemical air pollution, reduced visibility, eutrophication of surface waters, changes in biodiversity, acid rain, stratospheric ozone depletion, and global warming. In this study, ambient emissions of reactive nitrogen (ammonia and nitrous oxide) from animal and crop farming are analyzed for the base year 2003. This objective was achieved by the systematic development of a spatially resolved emissions inventory on a Geographic Information System (GIS) platform. Emissions of ammonia (NH3) and nitrous oxide (N2O) were estimated: (i) from livestock; 1705 Gg/yr and 214 Gg yr−1 and (ii) fertilizer applications; 2697 Gg yr−1 and 326 Gg yr−1. These estimated emissions were compared and contrasted with global, U.S., and European emissions of reactive nitrogen; emissions from India were second only to China. From the spatially resolved emission inventory, it was observed that the state of Uttar Pradesh has the highest NH3 emission (522 Gg yr−1) followed by the state of Maharashtra (425 Gg yr−1) both from animal and crop farming. Similarly the State of Uttar Pradesh has the highest N2O emission (70 Gg yr−1) followed by the state of Maharashtra (47 Gg yr−1).

► Agricultural operations emit significant amounts of reactive nitrogen compounds.
► Estimating nitrogen compounds emissions in India from agricultural sources.
► Comparison of agricultural nitrogen compounds emissions in India with global, U.S., and European emissions.
► Suggestions for developing an appropriate regulatory framework to control these emissions.