Productivity of 'Robusta' coffee trees in response to different pruning systems in an acid upland soil

Pruning of coffee trees is one of the most important cultural practices vital to stimulating the production of new wood, intensifying the formation of flowers and fruit buds while keeping the tree at a manageable size to facilitate easy harvesting. The experiment aimed to evaluate yield increase and the profitability of rejuvenating 22-year-old 'Robusta' coffee trees in a plantation in an upland agroecosystem of Claveria, Misamis Oriental, Philippines. The study was laid out in a simple RCBD with five treatments which were replicated three times with eight trees per treatment per replication. Pruning was done by cutting all old stems at about 40 cm from ground level. The treatments were imposed as follows: PS0 AS - all water sprouts allowed to grow; PS1 2Sdb - two vigorous water sprouts allowed to grow and maintained at approximately 1.5 m height; PS2 4Sdb - four vigorous water sprouts were maintained at 1.5 m height; PS3 2S - two vigorous water sprouts were allowed to grow to their full height; and PS4 4S - four vigorous water sprouts were allowed to grow to their full height. Allowing all water sprouts to grow (PS0 AS) had significantly greater responses when compared with the other pruning treatments. Rejuvenation using the PS0 AS and PS3 2S pruning systems can be considered as a suitable mechanism for reviving and extending the productive life of old coffee trees. Return on investment (ROI) analysis after the fourth year of pruning showed that the PS0 AS treatment, followed by PS3 2S treatment, gave the highest values which were associated with greater profitability.