Integrated Toposequence Analysis at the confluence zone of the River Ebonyi headwater catchment (south eastern Nigeria)

An integrated survey along a continuum of two representative toposequences, crossing fluvial and interfluvial landscapes downstream of the confluence of two perennial rivers of the upper reaches of the River Ebonyi catchment resulted in a methodology for characterising toposequences and for identifying priorities for land evaluation. The so-called Integrated Toposequence Analysis (ITA) merges conventional biophysical surveying and participatory research techniques along toposequences and sets a framework for developing relational databases for land resource mapping at village and catchment scale. Relationships between physiographic position, soil characteristics, vegetation and land use demonstrate the physical and human influences affecting the current land status along the catenae. Indigenous appraisal of soil characteristics and productivity provides insight in current land use strategies at farm level, whereas, analysis from standard biophysical methods demonstrates the constraints to present land use trends. Results indicate the limited scope for further agricultural intensification on the upland interfluve areas with the present farming system practices, and show the increasing pressure to exploit the fluvial wetlands.