LAND USE AND SLOPE POSITION EFFECT ON THE HYDROLOGICAL PROPERTIES OF SANDY LOAM SOILS OF KOUPENDRI CATCHMENT, NORTH-WEST OF BENIN

Abstract

Background. Land use and landscape characteristics influence soil hydrological properties and catchment hydrology. Objective. To investigate the effect of land use and slope positions on soil hydrological properties. Methodology. The study was done in Koupendri catchment, northwest Benin. The experimental design was a 2x2 factorial scheme replicated ten times. The study considered two land use types and two slope positions. The soil texture was sandy loam with high gravel (50-71%) and low organic carbon (11-18.4 g/kg) contents. Results. The Ksat in-situ and steady state infiltration were significantly (p<0.05) influenced by land use. Higher Ksat values of 5.33-11.96 cm/h and steady state infiltration (13.53 cm/h) were obtained under fallow shrub-grassland (FSG) compared to 2.21-3.04 cm/h and 3.58 cm/h respectively under tilled maize-beans (MBT). At both daily and 30-minute timescales, the maximum in-situ soil moistures were 0.270cm3/cm3 and 0.393cm3/cm3, respectively under FSG compared to 0.221cm3/cm3 and 0.202cm3/cm3 recorded under MBT. The coefficient of variation (CV) of the soil hydrological properties was low (<10%) for BD and porosity, moderate (<30%) for 14 θi"> , 14θf"> , and Ksat in-situ and very high (>50%) for Ksat-Lab. Conclusion. Land use significantly influenced soil hydrological properties