Soils of the Ethiopian Highlands
The first Thompson lab paper in 2023 comes from the intensive field work and modeling undertaken by Liya Weldegebriel in the Lake Tana Basin in Ethiopia - check it out here! https://www.sciencedirect.com/science/article/pii/S0022169422016018#figA.10.
First, some reflection. Liya's work took place in the Lake Tana region in Ethiopia's highlands, an area that abuts the Tigraay region where terrible conflict raged for three years, and where, even 5 months into a peace deal, there is desperate need. Liya would not be able to do this work now, and she has more recently focused her efforts towards understanding and sharing the impacts of the conflict on the people of Ethiopia. We cannot progress towards environmental sustainability during conflict: peace is necessary first.
Even in times of peace, the Ethiopian Highlands face some challenges. The erosion rates there are probably the greatest in the world. The population is increasing, there are new pressures around hydroelectrical production, and loss of forested areas for agriculture risk further destabilising the hillslopes.
One challenge in addressing erosion in the Highlands is that the erosion and runoff generation don't happen in the same way there as in the arid zone of Ethiopia, where most soil and water conservation measures have been developed. Consequently there are risks of perverse outcomes if typical techniques like contour banking are applied without good knowledge of soil and runoff properties. Yet the soils of the region are poorly characterised, and most soil and water planning involves observations of surface soils alone.
Liya undertook detailed soil sampling campaigns and characterised the hydraulic properties of vertical soil profiles from different parts of the hillslope. Then she used that information to explore how well the surface soil properties would predict the saturation dynamics of the soils, and how effective pedotransfer functions were in predicting soil hydraulic properties from texture.
She showed that the complex geomorphic and volcanic history of the area produces unexpected lithological sequences which are exposed in different ways depending on the extent of surface erosion, and developed new approaches to estimate erosion and saturation risk.