Evaluation of Soil Losses by Wind Erosion under Different Soil and Residue Management Practices in
Niger, West Africa
C. Bielders, K. Michels, and J.L. Rajot
Abstract
In spite of the general recognition that wind erosion is a major land degradation
process in the Sahel, little quantitative information is available for that region on soil
losses by wind erosion under different management practices. An on-farm field experiment
was therefore setup in order to assess the effect of two types of residue management and
ridging on soil loss and millet productivity. Millet stover at a rate of 2 t ha-1
was either broadcast or placed in strips 30 cm wide. Both ridges and residue strips were
oriented perpendicular to the most erosive winds. Mass balance calculations based on
incoming and outgoing soil fluxes measured with BSNE sand traps indicated soil losses of
at least 36.1 t ha-1 on bare plots over a two year period. Strip residue plots
trapped at least 30.6 t soil ha-1 over the same period. Broadcast residue
trapped 66% less sediment than banded residue. Ridging reduced soil losses by an average
of 41% over two years compared to the bare control. On bare plots, millet yields declined
from 328 to 78 kg grain ha-1 in two years, whereas on strip residue plots
yields remained stable at around 500 kg grain ha-1. Wind erosion is a major
hazard in the Sahelian zone. Millet stover mulches at a rate of 2 t ha-1 can be
used effectively to prevent soil erosion. |
