N2O emissions due to nitrogen fertilizer applications in two regions of sugarcane cultivation in Brazil

Abstract

Among the main greenhouse gases (CO _2 , CH _4 and N _2 O), N _2 O has the highest global warming potential. N _2 O emission is mainly connected to agricultural activities, increasing as nitrogen concentrations increase in the soil with nitrogen fertilizer application. We evaluated N _2 O emissions due to application of increasing doses of ammonium nitrate and urea in two sugarcane fields in the mid-southern region of Brazil: Piracicaba (São Paulo state) and Goianésia (Goiás state). In Piracicaba, N _2 O emissions exponentially increased with increasing N doses and were similar for urea and ammonium nitrate up to a dose of 107.9 kg ha ^−1 of N. From there on, emissions exponentially increased for ammonium nitrate, whereas for urea they stabilized. In Goianésia, N _2 O emissions were lower, although the behavior was similar to that at the Piracicaba site. Ammonium nitrate emissions increased linearly with N dose and urea emissions were adjusted to a quadratic equation with a maximum amount of 113.9 kg N ha ^−1 . This first effort to measure fertilizer induced emissions in Brazilian sugarcane production not only helps to elucidate the behavior of N _2 O emissions promoted by different N sources frequently used in Brazilian sugarcane fields but also can be useful for future Brazilian ethanol carbon footprint studies.

Keywords

• greenhouse gases
• ammonium nitrate
• urea
• global warming
• ethanol