ABSTRACT
En Tibacuy, Cundinamarca, Colombia, se encuentran culti- vos de café, tanto a pleno sol como con diferentes coberturas arbóreas y de plátano (Musa AAB); sin embargo, no se han realizado investigaciones que estudien las interacciones entre el dosel de sombra y el cultivo. Esta investigación, se centró en evaluar la respuesta ecofisiológica de plantas de cafeto cv. Castillo en sistemas agroforestales (SAF), con tres niveles de sombra: baja, de 0 a 20%; media, 21 a 47% y alta, de 48 a 70%. Se seleccionaron cinco fincas por condición de sombra, con cafetales de 4 a 6 años. En cada predio, se estableció una parcela de 1.000m², en la que se realizaron tres muestreos en el 2015: periodo lluvioso-enero, época de transición-junio y época seca-julio. En cada parcela, se se- leccionaron tres plantas de café representativas y en cada planta tres hojas, una por estrato vertical: bajo, medio y alto. Se midió la radiación fotosintéticamente activa incidente (RAFAi), conductancia estomática, transpiración y asimila- ción neta de carbono, con un sistema de fotosíntesis porta- ble CIRAS-3. Los resultados indican que niveles de sombra entre 48 y 70% afectaron negativamente la fotosíntesis de las plantas de café, mientras que con niveles de sombra, hasta de 47%, se obtiene una eficiencia fotosintética similar a plantas de café a pleno sol. Estos resultados son importantes para las decisiones de establecimiento y de manejo de sistemas productivos de café, principalmente, las relacionadas con el dosel de sombra.
Coffee crops under full sun and different tree covers and plantain (Musa AAB) are located in Tibacuy, Cundinamarca, Colombia; however, no studies about interactions between canopy layer and the crop have been carried out. This research is focused in evaluating the ecophysiological performance of coffee bushes cv. Castillo in agroforestry systems (AFS) under three conditions of tree and plantain (Musa AAB) shade: low shade, 0-20%, medium shade, 21-47% and high shade, 48-70%. Five farms by type of shade with coffee plantations in production, aged between 4 and 6 years were selected. In each place, a sampling plot of 1000m² was established in which three recordings were taken in 2015: rainy season, January, transition period, June, and dry season, July. In each sampling plot, three representative coffee plants were selected, which were representative and in each plant, three leaves were selected: one by vertical strata: low, medium and high. The incident radiation photosynthetically active (PARi), stomatal conductance, transpiration and net assimilation of CO2 were measured with a portable photosynthesis system CIRAS 3. The results show that high levels of shade between 48 and 70% negatively affected the photosynthesis rates of coffee plants; whereas with medium levels of shade up to 47% a similar photosynthetic efficiency than plants under full sun was obtained. These results are important inputs to consider in taking decisions for the establishment and management of coffee production systems regarding shade canopy.