BG Biogeosciences BG Biogeosciences 1726-4189 Copernicus Publications Göttingen, Germany 10.5194/bg-10-4179-2013 Nitrous oxide emissions from soil of an African rain forest in Ghana Castaldi S. 1 2 Bertolini T. 2 Valente A. 1 Chiti T. 2 Valentini R. https://orcid.org/0000-0002-6756-5634 2 3 DISAFRI, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy EuroMediterranean Centre for Climate Change, via Augusto Imperatore 16, 73100, Lecce, Italy Department for Innovation in Biological, Agro-food and Forest Systems, University of Tuscia, via S. Camillo de Lellis, 01100 Viterbo, Italy 22 06 2013 10 6 4179 4187 Copyright: © 2013 S. Castaldi et al. 2013 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://bg.copernicus.org/articles/10/4179/2013/bg-10-4179-2013.html The full text article is available as a PDF file from https://bg.copernicus.org/articles/10/4179/2013/bg-10-4179-2013.pdf

Recent atmospheric studies have evidenced the imprint of large N<sub>2</sub>O sources in tropical/subtropical lands. This source might be attributed to agricultural areas as well as to natural humid ecosystems. The uncertainty related to both sources is very high, due to the scarcity of data and low frequency of sampling in tropical studies, especially for the African continent. The principal objective of this work was to quantify the annual budget of N<sub>2</sub>O emissions in an African tropical rain forest. Soil N<sub>2</sub>O emissions were measured over 19 months in Ghana, National Park of Ankasa, in uphill and downhill areas, for a total of 119 days of observation. The calculated annual average emission was 2.33 &plusmn; 0.20 kg N-N<sub>2</sub>O ha<sup>−1</sup> yr<sup>−1</sup>, taking into account the proportion of uphill vs. downhill areas, the latter being characterized by lower N<sub>2</sub>O emissions. N<sub>2</sub>O fluxes peaked between June and August and were significantly correlated with soil respiration on a daily and monthly basis. No clear correlation was found in the uphill area between N<sub>2</sub>O fluxes and soil water content or rain, whereas in the downhill area soil water content concurred with soil respiration in determining N<sub>2</sub>O flux variability. The N<sub>2</sub>O source strength calculated in this study is very close to those reported for the other two available studies in African rain forests and to the estimated mean derived from worldwide studies in humid tropical forests (2.81 &plusmn; 2.02 kg N-N<sub>2</sub>O ha<sup>−1</sup> yr<sup>−1</sup>).

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