Emissions of nitrous oxide (N2O) from soil surfaces and their historical changes in East Asia: a model-based assessment

Abstract

This study assessed historical changes in emissions of nitrous oxide (N 2 O), a potent greenhouse gas and stratospheric ozone-depleting substance, from the soils of East Asia to the atmosphere. A process-based terrestrial ecosystem model (VISIT) was used to simulate the nitrogen cycle and associated N 2 O emissions as a function of climate, land use, atmospheric deposition, and agricultural inputs from 1901 to 2016. The mean regional N 2 O emission rate in the 2000s was estimated to be 2.03 Tg N 2 O year −1 (1.29 Tg N year −1 ; approximately one-third from natural ecosystems and twothirds from croplands), more than triple the rate in 1901. A sensitivity analysis suggested that the increase of N 2 O emissions was primarily attributable to the increase of agricultural inputs from fertilizer and manure. The simulated N 2 O emissions showed a clear seasonal cycle and interannual variability, primarily in response to meteorological conditions and nitrogen inputs. The spatial pattern of the simulated N 2 O emissions revealed hot spots in agricultural areas of China, South Korea, and Japan. The average N 2 O emission factor (emission per unit nitrogen input) was estimated to be 1.38%, a value comparable to previous estimates. These biogeochemical modeling results will facilitate identifying ways to mitigate global warming and manage agricultural practices in this region.

Fraction of nitrous oxide production in nitrification and its effect on total soil emission: A meta-analysis and global-scale sensitivity analysis using a process-based model

“…During the simulation period, total N 2 O emission increased from 12.11 Tg N 2 O yr –1 in 1901 to 18.60 Tg N 2 O yr –1 in 2016 as a result of the increase of fertilizer and deposition inputs. See our resent study [32] on the temporal change and its driver of the regional N 2 O emissions.…”

“…This model was selected, because it has an intermediate complexity among the global N 2 O models and gave moderate results in the model intercomparison project [29]. Also, the model was used for a regional evaluation of soil N 2 O emission in East Asia, one of the highly human-influenced regions, demonstrating the credibility for broad-scale applications [32]. Briefly, the model consists of water, carbon, and nitrogen cycling schemes for terrestrial ecosystems and is aimed at assessing atmosphere–ecosystem exchange of greenhouse gases and trace gases.…”

MIROC-INTEG1: A global bio-geochemical land surface model with human water management, crop growth, and land-use change

“…The functions of the natural land ecosystem and their environmental responses are simulated by the sub-model VISIT (Vegetation Integrative SImulator for Trace gases) (Ito 2010;Ito et al, 2018). VISIT is a process-based terrestrial https://doi.org/10.5194/gmd-2019-184 Preprint.…”

A mass spectrometric multiple soil-gas flux measurement system with portable high-resolution mass spectrometer MULTUM coupled to automatic chamber for continuous field observation

“…Soil acts as either a source or sink of various atmospheric gases, including greenhouse gases (GHGs,e.g.,N2O,CO2,and CH4) (e,g., Oertel et al, 2016;Ito et al, 2018), oxygen (O2) (Turcu et al, 2005, Huang et al, 2018, and biogenic volatile organic compounds (BVOCs) (Insam and Seewald, 2010;Peñuelas et al, 2014;Szog s et al, 2017, Mäki et al, 2019. The behaviors of either emitting or absorbing soil gases and their magnitudes are highly variable depending on the soil properties, such as soil biological and physicochemical characteristics in the soil, which are affected by environmental factors such as soil temperature, moisture, nutrients, pH level, rainfalls, etc.…”