Introduction
Faidherbia albida is an important component of parkland agroforestry
systems in sub-Saharan Africa. In the Sudano-Sahelian zone, variable
numbers of trees are retained by farmers in cropped fields, usually to the
benefit of crops growing underneath. Documentation of this 'albida effect'
is well known to readers of agroforestry literature [3, 5]. 'Islands of fertility',
around mature albida trees are characterized by increased levels of soil
organic matter, cations, and phosphorus.
F. albida occurs naturally over much of the African continent. From the