Abstract: Land Use Change Impacts on Soil Carbon Stocks in Two Forest Reserves in Southwest Nigeria. (ASA, CSSA and SSSA International Annual Meetings (2016))

241-9 Land Use Change Impacts on Soil Carbon Stocks in Two Forest Reserves in Southwest Nigeria.

Tuesday, November 8, 2016: 2:00 PM

Phoenix Convention Center North, Room 128 B

Shade John Akinsete, Department of Environmental Health Sciences, University of Ibadan, Ibadan, NIGERIA, David Pelster, Livestock System and Environment, International Livestock Research Institute, Nairobi, Kenya and Labode Popoola, Department of Forest Resources Management, University of Ibadan, Ibadan, Nigeria

Audio File Recorded Presentation

Abstract:

Abstract

Inadequate available soil organic carbon (SOC) information from different land uses from Africa has limited the assessment and monitoring of soil C storage, contributions to atmospheric greenhouse gases and plausible climate change mitigation strategies from the continent. We quantified SOC (concentrations; fractions; and stocks) under different land uses and the impact of land use change on surface and deep C stocks which has been poorly addressed. Two soil taxonomic orders (Alfisol and Inceptisol) were sampled in southwest Nigeria at five soil depths (0-5; 5-15; 15-30; 30-60; 60-100 cm) under natural forest (NF), teak plantation (TP) and arable land (AL) in Onigambari (7°07′51.5″ to 7°10′14.5″ N; 3°51′38.1″ to 3°52′35.9″ E) and Omo (6°48′48.2″ to 6°50′31.6″ N; 4°21′26.9″ to 4°24′28.2″ E) forest reserves, in Oyo and Ogun States, respectively.

SOC stocks (Mg ha^-1) for land use:soil order combinations held in the upper 5, 30 (IPCC reference soil depth) and 100 cm, respectively at Onigambari were: NF_ALFISOL: 32.57, 14.40 and 13.35; TP_ALFISOL: 9.44, 8.02 and 7.18; AL_ALFISOL: 11.03, 10.81 and 10.38 and NF_INCEPTISOL: 13.43, 12.67 and 13.51; TP_INCEPTISOL: 17.79; 6.93 and 5.55; AL_INCEPTISOL: 15.02, 11.57 and 11.96. At Omo, SOC stocks were: NF_ALFISOL: 20.86, 15.10 and 20.86; TP_ALFISOL: 11.37, 11.70 and 16.40; AL_ALFISOL: 10.27, 11.04; 17.69 and NF_INCEPTISOL: 14.47, 16.18 and 23.36; TP_INCEPTISOL: 11.19, 13.60 and 13.90; AL_INCEPTISOL: 11.43, 8.34 and 8.88. Acid hydrolysable C (AHC) and non-hydrolysable C (NHC) fractions contributed 25 – 79% and 21 – 75%, respectively to total SOC across depths and land uses.

Findings from this study revealed soil carbon stocks losses, particularly in teak plantation with reference to natural forest. Also, current soil carbon stocks were lower than IPCC₂₀₀₆Guidelines for the study area. This information will guide all stakeholders on appropriate future land use planning and climate change mitigation strategies.

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