A. Mando et L. Stroosnijder, The biological and physical role of mulch in the rehabilitation of crustedsoil in the Sahel, SOIL USE M, 15(2), 1999, pp. 123-127
During three consecutive years (1993 - 1995) a split-plot design with three
replications was used to study the biological and physical role of mulch i
n the improvement of crusted soil water balance and its productivity in the
north of Burkina Faso. The main treatment was the use of an insecticide, t
o obtain plots with and without soil fauna (SF and NSF). The subsidiary tre
atment consisted of four mulch types randomly applied on subplots. These we
re straw of Pennisetum pedicellatum applied at 3 t ha(-1), woody material o
f Pterocarpus lucens applied at 6 t ha(-1) and composite (woody material an
d straw) treatments applied at 4 t ha(-1). In addition there was a control,
with no mulch (bare plot). Data on soil faunal activity runoff, sediment a
ccumulation from wind blown soil, vegetation cover and vegetation dry matte
r yield were collected on all plots.
The biological activity (mainly termites) in mulched plots was the key elem
ent in the efficacy of mulching to rehabilitate crusted soil. Water infiltr
ation and dry matter yield were statistically lower on NSF plots than on SF
plots and runoff and dry matter yield were not different from the values o
btained on bare plots. A significant correlation was found between runoff,
all vegetation data and termite-voids. Sediment accumulation due to the phy
sical barrier of the mulch was not found to be a significant factor in the
improvement of vegetation performance and the reduction of runoff.