Factors influencing the economic viability of three agroforestry systems in Eastern and Southern Africa

Abstract

The economic viability of agroforestry systems depends on endogenous and exogenous biophysical and socio-economic factors. Understanding of such factors helps to delineate recommendation domain areas as well as to identify modifications in such factors in order to improve the system's viability. Each system has strengths and limitations in terms of its economic viability across the various land-use systems in Eastern and Southern Africa. In this paper, three agroforestry systems—taungya (or shamba), Faidherbia albida mixed intercropping, and hedgerow intercropping—are reviewed in terms of factors influencing their economic viability. The taungya system's economic viability was found to be dependent on conditions where access to land is scarce and where the returns to labour were low. To improve the returns to labour for the farmers participating in the system, a more prominent role of the agricultural activities is suggested, while the Forestry Department's net returns may be improved by changing their objective function from maximizing net timber income per unit area to optimizing total net timber income by using their scarce resources to cover larger areas, sacrificing some timber output per unit area. Alternatively, an increased public awareness of the environmental value of forest areas may generate additional resources to Forestry Departments, which may be used to increase income generating opportunities for the participating farmers. Apart from biophysical conditions required for the Faidherbia albida system, no specific socioeconomic conditions for this existing system were identified except that the tree's role may vary depending on the priorities of the farmer, i.e. food, fuelwood or fodder. A critical factor for the long-term sustainability and potential expansion of the system is the time required to reap the benefits from newly established trees. Therefore, research should be focused on selecting and breeding shorter period species. The hedgerow intercropping system is still in its infancy and mostly tried under research station conditions. To identify exogenous biophysical factors which may influence the biological response of the system, it is proposed that a more indepth synthesis of existing research is conducted to identify such factors. Particular attention should be paid to responses under low rainfall conditions and/or acidic soil conditions. Government policy on prices of inputs such as fertilizers, seed(lings) and food crops were identified as major exogenous socioeconomic factors affecting the economic viability of the system. Key endogenous factors which would affect its economic viability are the management capability of farmers, labour costs for establishing and maintaining the system, as well as the costs of seeds or seedlings. Because cost of establishment is influenced by the establishment method, choice of species and the hedgerow arrangement, it is proposed that more research is focused on the effect of these factors on cost as well as crop yields.