Agroforestry for the densely populated Tanzanian highlands

This study examined the physical environmental conditions and the existing land use in the highland areas (> 1500m) and lower slopes (< 1500m) of the west Usambara Mountains, and on slopes of Kilimanjaro and Meru, with the objective of evaluating and characterizing a role for agroforestry.The already high and rapidly increasing human population coupled with shortage of land is the main justification for integrating the production of agricultural crops, livestock and fuelwood. The existing farming systems and the extent of the problem of shortage of land (farm size) are the determinants of the choice of promising agroforestry interventions to solve general problems of soil erosion, degradation of land, and shortages of fuelwood and fodder.In the west Usambara Mountains where, maize-beans-vegetable crop farming dominates agriculture, macrocontour strips and alley cropping, combined with conscious mulching on croplands, are suggested for soil conservation and provision of fuelwood and fodder. Woodlots and tree groves established with suitable species in unused or derelict sites can effectively complement fuelwood supply from croplands and grazing lands.With adequate mulching and use of farmyard manure the banana-coffee home garden agroforestry system on the slopes of Kilimanjaro and Meru is effective for soil conservation but, additional tree planting is unrealistic in the banana-coffee system. To decrease excessive pressure on the land and over utilization of the remaining trees, resettlement of landless people in less densely populated areas must be the obvious answer.In the dry livestock production areas, mainly on the western and northern slopes of Mount Meru, overstocking in combination with fire damage to vegetation is the main cause of severe soil erosion (by water and wind). Destocking in the area is an essential pre-requisite, this together with increased tree (as multipurpose woodlots, tree groves in degraded sites and shelterbelts and deferred/rotational grazing) are essential for improved fodder and fuelwood production and soil conservation. The current communal ownership of land, and semi-permanent production, need be refined to promote adoption of the recommended interventions.Complementary sharing of agroforestry research work amongst the existing research institutions that can contribute to agroforestry development in the study area is needed.