Predicted soil organic carbon stocks and changes in Kenya between 1990 and 2030
2007
Kamoni, P.T. | Gicheru, P.T.(Kenya Agricultural Research Institute, Nairobi (Kenya). National Agricultural Research Laboratories) | Wokabi, S.M(Kenya Agricultural Research Institute, Nairobi (Kenya). National Agricultural Research Laboratories) | Easter, M.(The National Resource Ecology Laboratory, Colorado state University, Fort Collins) | Milne, E.(The Met Office, Hadley Centre for climate prediction and Research, Fizroy Road) | Coleman, K.(The Agriculture and the Environment Division, Rothamsted Research, Harpenden, Herts) | Falloon, P.(The Met Office, Hadley Centre for climate prediction and Research, Fizroy Road) | Paustian, K.(The National Resource Ecology Laboratory, Colorado state University, Fort Collins)
Under the United Nations Framework Convention on Climate Change (UNFCCC), Non-Annex 1 countries such as Kenya are obliged to report green house gas (GHG) emissions from all sources where possible, including those from soils as a result of changes in land use or land management. At present, the convention encourages countries to estimate emissions using the most advanced methods possible, given the country circumstances and resources. Estimates of soil organic carbon (SOC) stocks and changes were made for Kenya using the Global Environment Facility Soil Organic Carbon (GEFSOC) Modelling System. The tool conducts analysis using three methods: (1) the Century general ecosystem model; (2) the RothC soil C decomposition model; and (3) the Intergovernmental Panel on Climate Change (IPCC) method for assessing soil C at regional scales. The required datasets included: land use history, monthly mean precipitation, monthly mean minimum and maximum temperatures for all the' agro-climatic zones of Kenya and historical vegetation cover. Soil C stocks of 1.4-2.0 Pg (0-20 em), compared well with a Soil and Terrain(SOTER) based approach that estimated rv 1.8-2.0 Pg (0-30 em). In 199048% of the country had SOC stocks of 18 t C ha -I and 20% of the country had SOC stocks of 18-30 t C ha -I, whereas in 2000 56% of the country had SOC stocks of 18 t C ha-I and 31 % ofthe country had SOC stocks of 18-30 t C ha-I. Conversion of natural vegetation to annual crops led to the greatest soil C losses. Simulations suggest that soil C losses remain substantial throughout the modelling period of 1990-2030. All three methods involved in the GEFSOC System estimated that there would be a net loss of soil C between 2000 and 2030 in Kenya. The decline was more marked with RothC than with Century or the IPCC method. In non-hydric soils the SOC change rates were more pronounced in high sandy soils compared to high clay soils in most land use systems
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