Productivity of coffee plantations is threatened by both climate change and decreasing revenues of coffee growers. Using shade trees might protect against temperature variability, erosion and excessive radiation but there may be trade-offs in productivity and quality. While impacts of shade trees on arabica (Coffea arabica) have been reviewed, a global synthesis on robusta (Coffea canephora) coffee is lacking. We assessed how shade affects robusta growth and productivity, and what are the interactions and trade-offs. We conducted a systematic literature search in Web of Science and CAB Abstracts on 16 December 2019. Thirty papers fulfilled our inclusion criteria of being experimental studies on the impact of overstory trees with approximately half being from Brazil or India. Shade improved robusta tree growth and yield with some contrasting effects on physicochemical and biochemical properties. Shade (> 30%) was associated with reduced beverage quality. Significant interactions between shade and location, rainfall level and robusta clone were found. Among the clones tested, 06V, C153, LB1, GG229 and JM2 showed a higher productivity and growth (from + 17 to + 280%) under moderate shade (41–65%). This is the first meta-analysis of the effects of shade on robusta coffee. By synthesizing data from different studies, we highlight for the first time that the effect of shade on robusta coffee depends on tree age. Shade had positive impacts on older robusta trees (mean of 16 years), while the impact of shade on younger trees was either insignificant or negative. We highlight the importance of both clone type and tree ages. Research gaps included a lack of knowledge on the effects of shade with respect to coffee and shade tree age as well as interactive effects. More in-depth studies are needed to understand the mechanisms of how shade trees affect robusta coffee.

En esta investigación se evaluaron los cambios físicos y químicos que ocurren durante el crecimiento y maduración de la fruta llamada pitahaya. Utilizando la tabla de color de pitahaya amarilla (NTC-3554), se colectaron frutos en los seis estados de madurez (0 verde oscuro a 6 completamente amarillo) para evaluar el peso del fruto; mientras que para las variables porcentaje de pulpa y cáscara, firmeza de la pulpa (N), sólidos solubles (ºBrix), pH, acidez (%) y la evaluación sensorial de sabor y apariencia, se tomaron frutos solamente en dos estados (0 y 6). El porcentaje de cáscara disminuyó de 55.93 a 33.40 %; mientras que el de pulpa aumentó de 44.07 a 66.60 % entre el estado 0 y 6, respectivamente. El fruto al llegar al estado 6 presentó menor firmeza de pulpa (6.20 N), acidez titulable (0.14 %), y mayor contenido de sólidos solubles (20.74 ºBrix) y pH (4.86). Por otro lado, la prueba sensorial en los estados 0 y 6 fueron aceptados por el consumidor debido al alto contenido de grados Brix presentados en ambos estados.

Agroforestry systems have become an alternative that promotes the conservation of natural resources and the sustainable production of fruit crops in the Ecuadorian Amazon. However, it is required to demonstrate the benefit of the companion species that make up these production systems. The objective of this research was to determine how the legume species within an agroforestry system influence the yield of yellow dragon fruit (pitahaya), carbon sequestration and nutritional contribution. The experiment was carried out in Palora (province of Morona Santiago) and organized in a randomized complete block design with three replications. The treatments were two agroforestry arrangements and the monoculture as a control treatment. Erythrina poeppigiana, Gliricidia sepium and Flemingia macrophylla were used in the agroforestry arrangements for the contribution of biomass. Results showed that during the five years of study, pitahaya yield was influenced by the quality of the leaf litter (biomass) incorporated in to the fruit crop. Biomass from E. poeppigiana and F. macrophylla as companion crops contributed a greater amount of Ca and Mg, increased C sequestration and crop yield. The results suggest that the use of legume species in agroforestry systems positively affects pitahaya productivity, enabling sustainable agriculture in the Ecuadorian Amazon.

An application of a balanced nutrition will improve the soil as well as enhance the yield of naranjilla (Solanum quitoense Lam.) grown in the Ecuadorian Amazon. A field experiment was carried out in Palora, 16 de Agosto (Morona Santiago province) and Fátima (Pastaza province) to find which variables are related with the yield of the naranjilla crop and the yield response when the crop receives complete nutrition with N, P, K, Ca, Mg, and S plus lime and with the omission of each of these nutrients. A Random Complete Block Design with three replications was used in the three environments. The naranjilla crop had higher yields (18.14 Mg ha−1) in the complete treatments (N, P, K, Ca, Mg, and S) and without S and Mg, consequently, these two last nutrients did not limit the production. When N, P, K, and Ca were not applied, the yields fell to 14.62 Mg ha−1. The main environmental effect showed that Palora had the highest fruit yields (19.73 Mg ha−1), followed by 16 de Agosto (13.57 Mg ha−1) and finally Fátima with 11.04 (Mg ha−1). These preliminary results showed that with the treatments without S (18.55 Mg ha−1), without Mg (18.42 Mg ha−1) and complete (17.46 Mg ha−1) the highest yields were obtained, consequently, the production was not affected by the absence of these elements; the opposite happened when N, P, K, and Ca were not present.

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