LAND SUITABILITY FOR CROP DIVERSIFICATION AND YIELD POTENTIAL OF A DRAINED SWAMP AREA IN NW-TANZANIA

To meet the increasing demand for food, land use planning in NW-Tanzan ia recently focuses on swampy valley bottoms which are considered to h ave the highest production potential. Land development also aims at cr op diversification for nutrition improvement and self-sufficiency, Loc ally drainage projects are required to enable dry-season crop producti on. The pilot project data of the Bigombo Valley Development Project a re used to calculate the actual and potential lowland suitability acco rding to the parameter method suggested by SYS et al. (1991 AND 1993) for 9 different food crops. Local food crop priorities disagree strong ly with the climatic suitability. Landscape and soil suitability is ca lculated for three different soil wetness levels. The potential land s uitability for all crops is only marginal at the sub-optimal wetness l evel but moderate to very suitable at the optimum drainage level. When fully reclaimed, this land is very suitable for potatoes, beans and s oybeans while moderately suitable for onions, green peppers, cabbage, tomatoes, sweet potatoes and maize. The quantitative assessment of fiv e food crops according to the FAO-AEZ method (FAO 1979) confirms their suitability ranking except for potatoes. By relating the estimated fi gures to yield data for maize, the magnitude of the management factor is assessed, being similarly crucial for the crop production potential as soil wetness conditions.