DFG (Germany): Land use impact on hydro-biogeochemical fluxes and processes in tropical catchments of Kenya
DFG (Germany): Land use impact on hydro-biogeochemical fluxes and processes in tropical catchments of Kenya
Long term field measurements are required to investigate the effects of land use change on large scales and over extended periods of time. To achieve this, we installed four fully automatic measurement systems with UV hyperspectral sensors in the South West Mau, an area of tropical montane forests in the highlands of Kenya. They provide long-term data to quantify and compare hydro-biogeochemical dynamics (discharge, nitrate, turbidity, total and dissolved organic carbon) in catchments with natural forest, smallholder agriculture and commercial tea plantations. Measurements at the outlet of each subcatchment give a good indication of the effect land use on stream flow patterns and hydro-biogeochemical dynamics during dry and wet seasons. Within the DFG project, three different approaches were used to gain more knowledge on the influence of land use on hydro-biogeochemical processes in the South West Mau: |
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Suzanne R. Jacobs, Lutz Breuer, Klaus Butterbach-Bahl, David E. Pelster, Mariana C. Rufino (2017). Land use affects total dissolved nitrogen and nitrate concentrations in tropical montane streams in Kenya. Science of The Total Environment, Volumes 603–604, Pages 519-532. URL: https://www.sciencedirect.com/science/article/pii/S0048969717315048 |
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2018). Using high-resolution data to assess land use impact on nitrate dynamics in East African Tropical Montane Catchments. Water Resources Research, 54, 1812– 1830. URL: agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017WR021592 | , , , , , & (
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The activities in the South West Mau are not limited to the results presented here. Infiltration measurements and analysis of soil physical and hydraulic properties of samples collected from more than 100 sites in the study area revealed that conversion of natural forest led to significant soil degradation and reduced infiltration rates. More work is carried out with regard to soil erosion, estimating sediment export and understanding the sources of sediments in stream water, which are a problem in the smallholder catchment in particular. Other ongoing activities include characterisation of the smallholder farming systems and their related nitrogen inputs and exports to complete a nitrogen balance for the dominant land use types in the South West Mau. The monitoring activities are still ongoing to create a long-term high quality dataset on hydrology and stream water chemistry in tropical montane streams to advance our understanding of land use and climate influences on hydro-biogeochemical processes. |
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