Understanding N2O Emissions in African Ecosystems: Assessments from a Semi-Arid Savanna Grassland in Senegal and Sub-Tropical Agricultural Fields in Kenya
Authors:Bigaignon, LaurentDelon, ClaireNdiaye, OusmaneGaly-Lacaux, CorinneSerca, DominiqueGuerin, FredericTallec, TiphaineMerbold, LutzTagesson, TorbernFensholt, RasmusAndre, SylvainGalliau, Sylvain
Source:SUSTAINABILITY
Volume:12
Published:2020
Document Type:Article
Abstract:This study is based on the analysis of field-measured nitrous oxide (N2O) emissions from a Sahelian semi-arid grassland site in Senegal (Dahra), tropical humid agricultural plots in Kenya (Mbita region) and simulations using a 1D model designed for semi arid ecosystems in Dahra. This study aims at improving present knowledge and inventories of N2O emissions from the African continent. N2O emissions were larger at the agricultural sites in the Mbita region (range: 0.0 +/- 0.0 to 42.1 +/- 10.7 ngN m(-2) s(-1)) than at the Dahra site (range: 0.3 +/- 0 to 7.4 +/- 6.5 ngN m(-2) s(-1)). Soil water and nitrate (NO3-) contents appeared to be the most important drivers of N2O emissions in Dahra at the seasonal scale in both regions. The seasonal pattern of modelled N2O emissions is well represented, though the model performed better during the rainy season than between the rainy and dry seasons. This study highlighted that the water-filled pore space threshold recognised as a trigger for N2O emissions should be reconsidered for semi-arid ecosystems. Based on both measurements and simulated results, an annual N2O budget was estimated for African savanna/grassland and agricultural land ranging between 0.17-0.26 and 1.15-1.20 TgN per year, respectively.
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Reprint Address:Bigaignon, L; Delon, C (corresponding author), Univ Toulouse, Lab Aerol, UPS, CNRS, F-31013 Toulouse 6, France.; Bigaignon, L (corresponding author), Univ Toulouse, Ctr Etud Spatiales BIOsphere, CNES, UPS,IRD,CNRS, F-31013 Toulouse 6, France.
Addresses:[Bigaignon, Laurent; Delon, Claire; Galy-Lacaux, Corinne; Serca, Dominique; Andre, Sylvain; Galliau, Sylvain] Univ Toulouse, Lab Aerol, UPS, CNRS, F-31013 Toulouse 6, France. [Bigaignon, Laurent; Tallec, Tiphaine] Univ Toulouse, Ctr Etud Spatiales BIOsphere, CNES, UPS,IRD,CNRS, F-31013 Toulouse 6, France. [Ndiaye, Ousmane] Inst Senegalais Rech Agr, Ctr Rech Zootech, BP 3120, Dakar, Senegal. [Guerin, Frederic] Univ Toulouse, Geosci Environm Toulouse, CNRS, UPS,IRD,CNES, F-31013 Toulouse 6, France. [Merbold, Lutz] Int Livestock Res Inst, Mazingira Ctr, Nairobi 30709, Kenya. [Merbold, Lutz] Agroscope, Res Div Agroecol & Environm, Reckenholzstr 191, CH-8046 Zurich, Switzerland. [Tagesson, Torbern] Lund Univ, Dept Phys Geog & Ecosyst Sci, Box 117, S-22100 Lund, Sweden. [Tagesson, Torbern; Fensholt, Rasmus] Univ Copenhagen, Dept Geosci & Nat Resource Management, DK-1165 Copenhagen, Denmark.
E-mail Addresses:bigaignon.laurent@gmail.com; claire.delon@aero.obs-mip.fr; fisco42000@yahoo.fr; corinne.galy-lacaux@aero.obs-mip.fr; dominique.serca@aero.obs-mip.fr; frederic.guerin@ird.fr; tiphaine.tallec@cesbio.cnes.fr; l.merbold@cgiar.org; torbern.tagesson@ign.ku.dk; rf@geo.ku.dk; sylvain.andre1996@gmail.com; sylv.galliau@gmail.com