N ₂ O 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.

Enhanced-Efficiency Fertilizers in Nitrous Oxide Emissions from Urea Applied to Sugarcane

“…This value is close to the default value of 1% of the N applied used by the IPCC (IPCC, 2006) but lower than those of other field studies with sugarcane (Allen et al, 2010;Carmo et al, 2013;Denmead et al, 2010;Signor et al, 2013;Weier et al, 1998). Carmo et al (2013) found an emission factor of 0.7% of N applied as urea in sugarcane fields in Brazil, but the fertilizer emission factor increased to 3% when vinasse and harvest trash were present.…”

“…However, when vinasse, a residue of ethanol production, was applied, the N fertilizer emission factor increased to 3%. In two other regions in Brazil, Signor et al (2013) reported higher losses of N 2 O in sugarcane fields than those reported by Carmo et al (2013).…”

“…2). Other researchers also showed greater N 2 O emissions in the first weeks after N fertilizer application, attributing this effect to increased N availability for nitrification and denitrification processes and favorable environmental conditions for N 2 O emissions such as rainfall, high soil moisture, temperature, and available C ( Jumadi et al, 2008;Linzmeier et al, 2001;Menéndez et al, 2006;Signor et al, 2013;Weitz et al, 2001;Zaman et al, 2008).…”

Global metaanalysis of the nonlinear response of soil nitrous oxide (N 2 O) emissions to fertilizer nitrogen

“…However, results from a growing number of field experiments with multiple N fertilizer rates indicate that emissions of N 2 O respond in an exponentially increasing manner to increasing N inputs across a range of fertilizer formulations, climates, and soil types (e.g., refs. [13][14][15][16], suggesting that EFs are not constant but increase monotonically with N additions.…”

Sugarcane residue management impact soil greenhouse gas

“…The influence of management practices on GHG emissions associated with sugarcane production has been the focus of numerous studies comparing conventional to reduced tillage (Packer et al, 2015), increasing soil organic matter , fertilizer applications (Signor;Cerri;Conant, 2013) and crop rotations (Oliveira Bordonal et al, 2013). The current studies that have examined alterations in the GHG balances have used life-cycle approaches.…”