Water content and land use history controlling soil CO2 respiration and carbon stock in savanna soil and groundnut fields in semi-arid Senegal

• Published in: Geografisk tidsskrift Vol. 103; no. 2; pp. 47 - 56
• Main Authors: Elberling, Bo, Fensholt, Rasmus, Larsen, L., Petersen, A-I. S., Sandholt, Inge
• Format: Journal Article
• Language: English
• Published: København Taylor & Francis Group 01.01.2003; Kongelige danske geografiske selskab
• Subjects: Bgi / Prodig; Biogeography; Ecosystems and biological productivity; effluxes; groundnut cultivation; land use; Physical geography; Senegal; Soil respiration; West Africa; Senegal; Carbon cycle; Peanut; Biogeochemistry; Soil properties; Ecosystem; Carbon dioxide; Soil water; Cultivated land; Land use; Savanna
• ISSN: 0016-7223; 1903-2471
• DOI: 10.1080/00167223.2003.10649491

Decomposition of soil organic carbon (SOC) regulates the partitioning between soil C-stock and release of CO 2 to the atmosphere and is vital for soil fertility. Agricultural expansion followed by decreasing amounts of SOC and soil fertility is a problem mainly seen in tropical agro-ecosystems where fertilizers are in short supply. This paper focuses on factors influencing temporal trends in soil respiration measured as CO 2 effluxes in grass savanna compared with groundnut (Arachis hypogaea L.) fields in the semi-arid part of Senegal in West Africa. Based on laboratory experiments, soil CO 2 production has been expressed as a function of temperature and soil water content by fit equations. Field measurements included soil CO 2 effluxes, soil temperatures and water contents. Effluxes in grass savanna and groundnut fields during the dry season were negligible, while effluxes during the rainy season were about 3-8 μmol CO 2 m −2 s −1 , decreasing to less than 1 μmol by the end of the growing season. Annual soil CO 2 production was simulated to be in the range of 31-38 mol C m −2 . Furthermore, a controlled water addition experiment revealed the importance of rain during the dry season for the overall turnover of soil organic matter.