Impact of fruit phenology on water use in Robusta coffee systems in central Uganda

Abstract

Understanding the role played by agro- forestry systems in improving water use efficiency (WUE) in coffee is a fundamental issue that could help promote sustainable agriculture. This study determined water use of Robusta coffee at various phenological stages under Albizia coriaria shade tree and open sun coffee systems. A randomized complete block design (RCBD) was set up in the two systems; A. coriaria coffee system (ACS) and Open sun coffee system (COSS) having three coffee clones. Water use by coffee and shade trees was measured using sap flow meters. In addition, days from inflorescence emergence to ripening and berry size from yellow berries to ripening were also measured. An ANOVA was used to ascertain differences in water use and berry growth duration. The results showed that Robusta coffee water use per phenological stage was clone and system dependent. COSS significantly (p < 0.001) used more water per day (1.43 l/day) compared to coffee under ACS (0.62 l/day), representing a 40% difference in daily water use between the two coffee systems. The fruit phenological stages under ACS required a longer duration (397.78 days) compared to COSS (350.94 days). A significant impact of the coffee system and clone on coffee water use was observed, potentially indicating reduced demand for water under A. coriaria compared to open sun coffee.