Sc. Geiger et al., VARIABILITY IN THE GROWTH OF FAIDHERBIA-ALBIDA - THE SOILS CONNECTION, Soil Science Society of America journal, 58(1), 1994, pp. 227-231
Variability in the growth of Faidherbia albida (Del.) A. Chev. (syn. A
cacia albida [Del.1) in the Sahelian zone of West Africa is a common o
bservation. The ''albida effect'' has been attributed to the ameliorat
ion of soil chemical, physical, and microbiological properties by the
direct action of the tree, resulting in enhanced crop production benea
th the mature canopy. Crop yields within fields without F. albida can
also be highly variable within short distances. A study was conducted
to observe the association between the variability in soil properties
and the variable growth of young (2-yr-old) F. albida trees planted at
the ICRISAT Sabelian Center located near Niamey, Niger. The results o
f this study indicate that the variability in F. albida growth is caus
ed, in large part, by variability in soil properties across relatively
short distances. Good growth sites had higher clay contents and base
saturations, and lower exchangeable acidity than poor growth sites wit
hin the field. The tallest trees in the field were associated with the
proximity to abondoned termite mounds and other microhigh sites. Seed
lings planted on sheet-eroded sites caused by runoff from microtopogra
phical high sites within the field grew poorly. The variability in F.
albida growth in plantations within Niger is hypothesized to be due, i
n part, to preexisting soil conditions. These results also suggest tha
t the albida effect might be partially caused by these preexisting ''i
slands of fertility''. This site-determined variable growth of F. albi
da could be exploited with proper seedling placement strategies.