Estimation of nitrous oxide, nitric oxide and ammonia emissions from croplands in East, Southeast and South Asia

Abstract

Agricultural activities have greatly altered the global nitrogen (N) cycle and produced nitrogenous gases of environmental significance. More than half of all chemical N fertilizer produced globally is used in crop production in East, Southeast and South Asia, where rice is central to nutrition. Emissions of nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3) from croplands in this region were estimated by considering background emission and emissions resulting from N added to croplands, including chemical N, animal manure, biologically fixed N and N in crop residues returned to fields. Background emission fluxes of N2O and NO from croplands were estimated to be 1.22 and 0.57 kg N ha−1 yr−1, respectively. Separate fertilizer‐induced emission factors were estimated for upland fields and rice fields. Total N2O emission from croplands in the study region was estimated to be 1.19 Tg N yr−1, with 43% contributed by background emissions. The average fertilizer‐induced N2O emission, however, accounts for only 0.93% of the applied N, which is less than the default IPCC value of 1.25%, because of the low emission factor from paddy fields. Total NO emission was 591 Gg N yr−1 in the study region, with 40% from background emissions. The average fertilizer‐induced NO emission factor was 0.48%. Total NH3 emission was estimated to be 11.8 Tg N yr−1. The use of urea and ammonium bicarbonate and the cultivation of rice led to a high average NH3 loss rate from chemical N fertilizer in the study region. Emissions were displayed at a 0.5° × 0.5° resolution with the use of a global landuse database.

Satellite constraint for emissions of nitrogen oxides from anthropogenic, lightning and soil sources over East China on a high-resolution grid

“…Zhao and Y. Wang, personal communication, 2011). Soil emissions derived from the inverse modeling also differ from the bottom-up estimates (Yienger and Levy, 1995;Yan et al, 2003Yan et al, , 2005Hudman et al, 2012;Steinkamp and Lawrence, 2011); in particular, they are 50-300 % larger than the Yienger and Levy (1995) estimate. According to Jaeglé et al (2005) and Wang et al (2007), soil emissions may be as large as 40-50 % of anthropogenic emissions in summer for East Asia in 2000 and for East China in 1997-2000, respectively, with significant implications for the global biogeochemical cycling of nitrogen.…”

A global model study of the impact of land-use change in Borneo on atmospheric composition

“…The PALMX scenario includes NO x emissions from industrial processing and fertilisation of oil palm over Borneo, in addition to the larger oil palm isoprene emissions in PALM. NO x emissions from fertilised soils were based on OP3 observations of N 2 O and parameterisations of ratios of NO and N 2 O from croplands in SE Asia (Yan et al, 2003). They total 0.8 Mg(NO 2 ) km −2 yr −1 and were emitted as annual pulse emissions decaying linearly over a twomonth period following fertiliser application to a background flux of 0.05 kg(NO 2 ) km −2 yr −1 .…”

The impact of local surface changes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land-use change and air quality

“…All integrations were forced with meteorological analyses from 2008. NO x emissions from fertilized soils were based on OP3 observations of N 2 O, as well as parametrizations of ratios of NO and N 2 O from croplands in South East Asia [51]. The emissions totalled 0.8 Mg(NO 2 ) km 22 yr -1 and were emitted as annual pulse emissions decaying linearly over a two month period following fertilizer application to a background flux of 0.05 kg(NO 2 ) km 22 yr -1 .…”