Abstract

Assessment of soil erosion risk is important to formulate effective soil conservation plans for sustainable development. Information from remote sensing techniques can help decision makers prepare resource map accurately in less time and cost. GIS assists in linking those maps with other information related to geographic location and helps modeling, analyzing and solving complex problems. The objective of this study was to assess the potential of Morgan, Morgan and Finney (MMF) Model (Morgan et al., 1984) in predicting soil erosion in an agrarian Ekiti environment with highly dissected hilly and rolling terrain in southwestern Nigeria. Soil loss prediction by MMF approach involve factor maps from kinetic energy of rainfall, topsoil rooting depth, percentage rainfall contri-buting to permanent interception and stream flow, crop cover management factor, ratio of actual to potential evapotranspiration, soil moisture storage capacity. These were used to generate output maps like volume of overland flow, rate of soil detachment by raindrop impact and transport capacity of overland flow. Annual soil loss estimation was calculated by comparing two maps of soil detachment rate and transport capacity and taking the minimum value from them. Results showed that MMF model could predict erosion risks effectively in the highly dissected hilly and rolling landscape of Ekiti environ. Erosion was low in the area in spite of the landscape. The highest soil loss was 1.275 kgm^-2 yr^-1 from rock hill with slope greater than 15%. The lowest was 0.942 kgm^-2 yr^-1 at low lands covered with riparian forest. The average estimated annual soil loss of the study area was 1.112 kgm^-2, which is less than tolerable standard of 1 kg 1233 m^-2 yr^-1. The MMF model shows that the current land-use/cover in Ekiti environs is sustainable because erosion risk is below the critical level.

Key words: Soil erosion, MMF model, land use, hilly landscape, Nigeria.