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The effects of catena positions on greenhouse gas emissions along a seasonal wetland (dambo) transect in tropical Zimbabwe
- Nyamadzawo, George, Wuta, Menas, Nyamangara, Justice, Rees, Robert M, Smith, Jeffry L.
- Archiv für Acker- und Pflanzenbau und Bodenkunde 2015 v.61 no.2 pp. 203-221
- carbon dioxide, greenhouse gas emissions, greenhouse gases, highlands, methane, methane production, nitrous oxide, seasonal wetlands, Zimbabwe
- Wetlands are major natural sources of greenhouse gases (GHGs). In central and southern Africa, one of the most extensive wetlands are dambos (seasonal wetlands) which occupy 20–25% of land area. However, there are very little data on GHG methane (CH₄), carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions from dambos, and this study presents the first estimates from dambos in Zimbabwe. The objective was to evaluate the effects of catena positions; upland, dambo mid-slope and dambo bottom, on GHG emissions along an undisturbed dambo transect. Methane emissions were −0.3, 29.5 and −1.3 mg m⁻² hr⁻¹, N₂O emission were 40.1, 3.9 and 5.5 µg m² hr⁻¹, while CO₂ emissions were 2648.9, 896.2 and 590.1 mg m⁻² hr⁻¹ for upland, mid-slope and bottom catena, respectively. Our results showed that uplands were important sources of N₂O and CO₂, and a sink for CH₄, while the dambo mid-slope position was a major source of CH₄, but a weak source of CO₂ and N₂O. Dambo bottom catena was weak source GHGs. Overall, dambos were major sources of CH₄ and weak sources of N₂O and CO₂.We concluded that, depending on catenal position, dambos can be major or minor sources of GHGs.