Disaggregated N2O emission factors in China based on cropping parameters create a robust approach to the IPCC Tier 2 methodology. (December 2015)

• Record Type: Journal Article
• Authors: Shepherd, Anita; Yan, Xiaoyuan; Nayak, Dali; Newbold, Jamie; Moran, Dominic; Dhanoa, Mewa Singh; Goulding, Keith; Smith, Pete; Cardenas, Laura M.
• Is Part Of: Atmospheric environment. Volume 122(2015)
• Page Start: 272
• Page End: 281
• Publication Date: 2015-12
• Subjects: China -- Nitrous oxide -- Emission factor -- Greenhouse gas -- Fertilizer -- Agriculture; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2015.09.054
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: China accounts for a third of global nitrogen fertilizer consumption. Under an International Panel on Climate Change (IPCC) Tier 2 assessment, emission factors (EFs) are developed for the major crop types using country-specific data. IPCC advises a separate calculation for the direct nitrous oxide (N2 O) emissions of rice cultivation from that of cropland and the consideration of the water regime used for irrigation. In this paper we combine these requirements in two independent analyses, using different data quality acceptance thresholds, to determine the influential parameters on emissions with which to disaggregate and create N2 O EFs. Across China, the N2 O EF for lowland horticulture was slightly higher (between 0.74% and 1.26% of fertilizer applied) than that for upland crops (values ranging between 0.40% and 1.54%), and significantly higher than for rice (values ranging between 0.29% and 0.66% on temporarily drained soils, and between 0.15% and 0.37% on un-drained soils). Higher EFs for rice were associated with longer periods of drained soil and the use of compound fertilizer; lower emissions were associated with the use of urea or acid soils. Higher EFs for upland crops were associated with clay soil, compound fertilizer or maize crops; lower EFs were associated with sandy soil and the use of urea. Variation in emissions for lowland vegetable crops was closely associated with crop type. The two independent analyses in this study produced consistent disaggregated N2 O EFs for rice and mixed crops, showing that the use of influential cropping parameters can produce robust EFs for China. Highlights: Disaggregated nitrous oxide emission factors create a more robust IPCC Tier 2 approach. Influential cropping factors give consistent emission factors for Chinese agriculture. Consistency in emission factors transcended method type, data quality and datasets.