Geomorphological and human environmental dynamics during the last 4000 years in Northern Ethiopia (Tigray)

Abstract

This paper aims to present the role of geomorphological and geoarchaeological techniques in the understanding of soil degradation, through time and space. In the case of the Axum-Adwa area, located at the province of the Tigray, the stratigraphic analysis of several infilled valleys, enabled the characterisation, for the last five millennia of degradation episodes, where there was an increase of sediment yield from the slopes into the valleys, and stability phases. Although climate can be pointed out as the main long-term driving factor of environmental change in the area, human actions play an important role in environmental degradation, particularly in a region with a long established agriculture background. The analysis of natural and human environments through time and space, enables therefore the identification, on one hand of the bio-physical variables controlling soil erosion processes, and on the other the possible socio-economic causes that may have led to soil degradation (e.g. land tenure, farming practices). Regarding the latter, and in particular for the last 100 years record, the information gathered through the use of geomorphological and geoarchaeological approaches, can and should be complemented by the one concerning farmer’s perception of those processes and possible triggering factors.