This study focused on evaluating the growth and productivity of Coffea arabica var. Esperanza L4A5 in different agroforestry systems in the Caribbean region of Costa Rica, a non-traditional area for coffee cultivation due to its low altitude and challenging climatic conditions. Three tree coverages were investigated, in combination with two types of differentiated fertilization (physical and chemical), comparing the results with full sun coffee plots as a control: (1) Albizia saman, (2) Hymenaea courbaril + Erythrina poeppigiana, and (3) Anacardium excelsum + Erythrina poeppigiana. The results showed that tree associations significantly reduced the mortality of coffee plants and increased both the height and mature cherry production compared to full sun treatments. In particular, the tree coverages associated with chemical and physical fertilization achieved the highest growth and production rates, with A. excelsum + E. poeppigiana and H. courbaril + E. poeppigiana standing out with maximum mature cherry productions of 3.35 t/ha and 3.28 t/ha, respectively. Growth analysis revealed that rapid initial growth, especially under chemical fertilization, is crucial for maximizing productivity, although a rapid slowdown in growth was also observed after reaching the peak. These findings underscore the importance of combining tree coverages with appropriate fertilization strategies to optimize coffee production in agroforestry systems, particularly in low-altitude areas like the Costa Rican Caribbean. This study concludes that agroforestry systems not only improve the resilience of coffee crops to adverse environmental conditions but can also be a viable strategy for increasing productivity in non-conventional regions. This suggests the need for further research to assess the long-term impacts on soil health, biodiversity, and the economic viability of these systems.

This research shows results on spatial changes of fine roots (d < 2.0 mm) in two Coffea arabica- shade tree associations: coffee shaded by a) Abarema idiopoda (timber and nitrogen fixing tree), and b) Terminalia amazonia (timber tree). These associations were submitted to organic and conventional inputs. In order to identify fine root vertical distribution and using soil cores, coffee and shade tree fine roots were quantified to 50 cm depth. A geostatistical approach was used to quantify the scale of spatial heterogeneity (aggregation patterns) of coffee and shade- tree fine root length density (RLD, cm cm-3; 0- 20 cm soil depth). Results about vertical distribution demonstrated that in all the associations the coffee fine roots were concentrated in the upper 20 cm of soil. The significant amount of coffee fine roots in the litter layer demonstrated the importance of including this layer for a real estimation of coffee fine roots in shaded coffee systems. The shade tree fine roots showed marked differences in their vertical distribution and affected the fine root density of coffee plants between 0- 50 cm soil depth; being more abundant when coffee is planted with T. amazonia. The scale of spatial heterogeneity (aggregation patterns) for coffee RLD was longer in the organic plot than in the conventional plot for all of the coffee- tree associations. In the coffee- T. amazonia association, the semivariogram of the coffee RLD under conventional management showed a spatial correlation at a relative short scale (3.5 m); however, in the organic plot, the semivariogram did not show spatial heterogeneity and exhibited a random pattern of coffee RLD at the scale examined. It is concluded that the type of management affects the pattern of spatial aggregation (spatial heterogeneity scale) of C. arabica fine roots. Implying that the ability of coffee roots for the water and nutrient intake change spatially, either vertically or horizontally, depending on the accompanying shade- tree. According to the occupation of the fine roots within the layers of the soil to the depth studied, T. amazonia seems to be the timber species recommended for the establishment of a coffee-based agroforestry system.