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Net global warming potential and greenhouse gas intensity
Author(s) -
Sainju Upendra M.
Publication year - 2020
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.1002/saj2.20152
Subject(s) - greenhouse gas , environmental science , global warming , global warming potential , sink (geography) , nitrous oxide , agriculture , carbon sequestration , soil carbon , soil respiration , environmental engineering , climate change , nitrogen , soil water , soil science , chemistry , ecology , cartography , organic chemistry , biology , geography
Agricultural practices contribute significant levels of greenhouse gas (GHG) emissions. Methods to measure net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of GHG emissions in agroecosystems are still evolving. Sources of GHGs include soil CO 2 , N 2 O, and CH 4 emissions and CO 2 emissions associated with farm operations, N fertilization, and other chemical inputs. Sinks of GHGs include CH 4 uptake, soil C sequestration, and crop residue returned to the soil. This chapter discusses the methods of measuring net GWP and GHGI using two approaches: In the soil organic C (SOC) method, net GWP and GHGI are calculated by using N 2 O and CH 4 emissions (or CH 4 uptake), as well as CO 2 emissions from farm operations, N fertilization, and other chemical inputs as GHG sources and C sequestration rate (ΔSOC) as GHG sink. In the soil respiration method, soil respiration (excluding root respiration) is included as another GHG source, and the previous year's crop residue returned to the soil instead of ΔSOC is included as GHG sink in addition to the above parameters. Advantages and drawbacks of each method of calculating net GWP and GHGI are also discussed.