Impact of Eucalyptus camaldulensis plantation on an alluvial soil in south eastern Botswana

Abstract

This paper examines the impact of a 33‐year plantation of Eucalyptus camaldulensis on an alluvial soil in Gaborone, south eastern Botswana, by comparing the soil under the plantation with similar soil under an adjoining native savanna woodland dominated by Acacia karoo. Soil clay content was significantly higher in the plantation soil in both the 0–10 cm and 10–20 cm layers. There were no significant differences between soil under the two ecosystems with respect to the levels of organic matter, exchangeable potassium and available phosphorus. Despite the higher clay contents of the plantation soil, exchangeable calcium and magnesium and pH were higher in soil under the native woodland. This suggests that E. camaldulensis immobilizes soil nutrients faster and that plantation nutrient cycles are less efficient than in the native Acacia woodland. Consequently, soil nutrient deficiency will limit plantation productivity after the first few rotations. It is important to adopt tree harvesting techniques that reduce drain on soil nutrients at the end of a plantation rotation.

Keywords:

• Botswana
• Eucalyptus camaldulensis
• Acacia karoo
• Soil nutrients
• Savanna

Acknowledgement

The authors would like to express their profound gratitude to Mr R. Rabalone and Ms Veronica Ngole, of the University of Botswana, for analyzing the soils and to Mr Maina, also of the University of Botswana, for assistance in field sampling of soil.

Notes

* Corresponding author.

Additional information

Notes on contributors

A.O. AWETO *

* Corresponding author.