The impact of deforestation on soil degradation in Eastern Africa
Central Africa is home to the second largest tropical forest on Earth. Along the steep topography of the East African Rift system, deforestation causes extreme soil erosion and loss of fertile topsoil. The rate of erosion, degree of soil degradation after deforestation on hillslopes, and the stabilization of plant nutrients and carbon in colluvia are still largely unknown. Moreover, the impact of the underlying rock mineralogy on the availability of nutrients for plant and minerals for carbon stabilization is not well understood.
Understanding these processes is hampered by the large gap in soil data for the region. Fast, accurate, and affordable methods, such as soil mid-infrared spectroscopy, are needed to analyze soil carbon and soil fertility properties and fill this data gap.
My research project aims to
i) establish a soil infrared library for central Africa to allow for the generation of large and detailed soil datasets,
ii) determine how long East African hillslope soils retain their fertile topsoils following deforestation, and
iii) ascertain whether plant nutrients and carbon are lost for plants and buried in deep layers of deposition sites.
With these results, we aim to improve our knowledge of how soil fertility can be maintained to reduce the need for agricultural expansion into forests and to better understand carbon stabilization processes and climate change mitigation potential of these highly erosive environments.
Impressions of field work
(Laura Summerauer) Rwenzori foothills near Fort Portal in Western Uganda
(Laura Summerauer) Soil core drilling in a colluvia, South Kivu, Democratic Republic of Congo
(Laura Summerauer) Colluvia sampled near Fort Portal in Western Uganda
(Laura Summerauer)
References
Summerauer, L., Baumann, P., Ramirez-Lopez, L., Barthel, M., Bauters, M., Bukombe, B., Reichenbach, M., Boeckx, P., Kearsley, E., Van Oost, K., Vanlauwe, B., Chiragaga, D., Heri-Kazi, A. B., Moonen, P., Sila, A., Shepherd, K., Bazirake Mujinya, B., Van Ranst, E., Baert, G., Doetterl, S., and Six, J.: The central African soil spectral library: a new soil infrared repository and a geographical prediction analysis, SOIL, 7, 693–715, external page https://doi.org/10.5194/soil-7-693-2021, 2021.
Laura Summerauer. (2022). laura-summerauer/ssl-central-africa: Data and codes to reproduce manuscript results (v.1.1). Zenodo. external page https://doi.org/10.5281/zenodo.6786666