Abstract:
Declining soil fertility is one of the major problems facing producers of field crops in
most dryland areas of Sub-Saharan Africa. In response to the declining soil fertility, extensive
participatory research has been undertaken by the World Agroforestry (ICRAF) and smallholder
farmers in Dodoma region, Tanzania. The research has, amongst others, led to the development of
Gliricidia agroforestry technology. The positive impact of Gliricidia intercropping on crop yields has
been established. However, information on farmers’ willingness and ability to adopt the Gliricidia
agroforestry technology on their farms is limited. This study predicts the adoption of Gliricidia
agroforestry and conventional mineral fertilizer use technology. Focus Group Discussions (FGDs)
were conducted with groups of farmers, purposively selected based on five sets of criteria: (i) at least
2 years of experience in either trying or using Gliricidia agroforestry technology, (ii) at least 1 year of
experience in either trying or using the mineral fertilizer technology (iii) at least 10 years of living
in the study villages, (iv) the age of 18 years and above, and (v) sex. The Adoption and Diffusion
Outcome Prediction Tool (ADOPT) was used to predict the peak adoption levels and the respective
time in years. A sensitivity analysis was conducted to assess the effect of change in adoption variables
on predicted peak adoption levels and time to peak adoption. The results revealed variations in peak
adoption levels with Gliricidia agroforestry technology exhibiting the highest peak of 67.6% in 12
years, and that the most influential variable to the peak adoption is the upfront cost of investing in
Gliricidia agroforestry and fertilizer technologies. However, in Gliricidia agroforestry technology
most production costs are incurred in the first year of project establishment but impact the long term
biophysical and economic benefits. Moreover, farmers practicing agroforestry technology accrue
environmental benefits, such as soil erosion control. Based on the results, it is plausible to argue that
Gliricidia agroforestry technology has a high adoption potential and its adoption is influenced by
investment costs. We recommend two actions to attract smallholder farmers investing in agroforestry
technologies. First, enhancing farmers’ access to inputs at affordable prices. Second, raising farmers’
awareness of the long-term environmental benefits of Gliricidia agroforestry technology.
