Impact of tree management on coffee and common bean productivity in smallholder agroforestry systems in Uganda

Abstract

In this study, we hypothesized that tree canopy pruning would positively influence the relative growth performance and productivity of coffee (Coffea arabica L.) and common beans (Phaseolus vulgaris L.) growing under Cordia africana and Albizia coriaria trees. The trees were subjected to a 50% pruning regime at a 6-month interval over a period of 20 months (July 2018 - February 2020), and common beans were introduced following local planting seasons. Yields of parchment coffee were highest under pruned Albizia (949 kg/ha). Unshaded coffee produced the least yield at 402 kg/ha and 422 kg/ha in the Albizia and Cordia sites respectively. While the highest common beans yields (708 kg/ha) were obtained from open field sites, beans that were planted under unpruned Cordia gave the least yield of 420 kg/ha. Unlike coffee, there was a significant variation in yield of common beans across the different management options (P<0.05). The results show that agroforestry tree canopy pruning is an important on-farm management decision for controlling competition while prolonging the period of intercropping in intensive farming systems. Farmers should deliberately prune agroforestry shade trees to minimize the negative effects of dense shading.