Accelerated soil erosion in Central Tanzania during the last few hundred years

Abstract

The Irangi Hills of Kondoa District in central Tanzania are severely affected by soil erosion. Exceptionally large gullies dissect the slopes and in many locations badlands have developed. Through analysis of a 3.6 m sediment record from the small Lake Haubi, reconstruction of the erosion and sedimentation sequences are attempted. A sediment chronology has been established based on analysis of 210Pb and 137Cs, which dates the record to the beginning of the 19th century. The formation of the present lake took place around the turn of the century and was possibly initiated by accumulation of erosion products at the outlet of the basin. The first phase of gully incision must have taken place before the 19th century. It is not known what initiated and triggered the processes, although it is likely that clearing of land for cultivation, grazing and charcoal burning in precolonial times have played a decisive role.