Abstract:
Erosion is one of the commonest environmental hazard that
has rendered useless millions of hectares of arable soils in the tropics.
This study was aimed at determining the runoff characteristics of
soils planted with cowpea at different densities.
Treatments were based on three densities: A (Bare soil) which
serves as the control, B (13 stands/rn-) and C (26 stands/rn-). Soil
moisture content was monitored using gravimetric method. Precipitation,
runoff, drainage depths and sediment yields were measured during
the experiment which was replicated twice. Rainfall-sediment yield
model was established for ease of prediction of runoff that could
occur from different precipitations. The water balance equation was
used to compute the evapotranspiration for each plot.
Results indicated that runoff depth was least in Treatment C
(26 stands/m-) and was highest on the bare soil. There were significant
difference in the sediment yield between the bare soil and the soil
planted with 26 stands/rn- of cowpea with the bare soil having the
highest value of sediment yield. Rainfall-sediment yield model show
R2= 0.9665 in bare soil and 0.9085 in well covered soil in the second
experiment respectively, an indication that plant density is a determinant
of the sediment yield from rainfalls at any period or time.
The result of this research work is useful in the prediction of
future runoffs based on the available' storm data for a period.
