Effects of Vetiver (Vetiveria nigritana) on Infiltration Characteristics of Kaolinitic Alfisol of Ibadan, South-Western Nigeria

The importance of erosion in relation to variability of water and soil losses from a parcel of land can be revealed in the measurements of the infiltration characteristics and runoff under a comparable vetiver grass strips and collection tanks within the plots. This experiment is aimed at assessing the variability of runoff and soil loss due to infiltration characteristics of the runoff plots. This study involved three vetiver plots of 20 m interval measured out of six plots (40 m × 3 m each) randomly distributed over a land area of 0.072 ha. The study was conducted on a 6 % slope experimental plot, along Parry Road of the University Ibadan, during the 2007 raining season. The texture of the soil was generally loamy sand. Mean total runoff among the plots was in the trend of no-vetiver plots > vetiver plots (13.50mm > 4.99 mm), the same was true for mean total soil loss (28.78kg/ha > 12.96kg/ha). Variability in the amounts of runoff was moderate in vetiver plots and highly variable in no-vetiver plots (CV = 24 % and 40 % respectively. The correlation between measured soil physical properties and infiltration characteristics with runoff revealed that fine sand content of the soil was negatively related with runoff (r = 0.6450*), but the reverse relationship was true for porosity inferred from soil bulk density and sorptivity of the soil (r = -0.7650*, and -0.8956* respectively).