Interacciones competitivas enter Coffea arabica y arboles maderables de rapido crecimiento en Pérez Zeledon, Costa Rica

In young, 2 - 4 year old Coffea arabica associations, tree stem diameter, crown projection and shade level were higher for the fast-growing timber species (Terminalia ivorensis) than for Eucalyptus deglupta. Coffee plants under timber tree shade received less light and transpired less than those under the service tree (Erythrina poeppigiana). This latter treatment resembled the full sun treatment due to wider tree spacing and two pollardings per year. Coffee berry production was higher under E. deglupta than in the two other associations. There was a horizontal partitioning of coffee and timber tree fine roots (diameter < 2.0 mm), and C. arabica was the stronger competitor. Lower soil moisture content and relative air humidity, and higher air temperatures and vapor pressure deficit values in the dry season (February - March) resulted in a decrease of water consumption by coffee and trees (especially E. deglupta and T. ivorensis). Coffee transpiration was increased by a vegetative growth spurt (March - April) and high evapotranspiration demand due to high solar radiation during these months. The combined transpiration of coffee and associated trees was higher than that of coffee in full sun in both dry and rainy periods. E. deglupta was the more promising coffee timber shade tree under the trial conditions (without major water limitations). (Résumé d'auteur