Effects of Inga densiflora on the microclimate of coffee (Coffea arabica L.) and overall biomass under optimal growing conditions in Costa Rica

Abstract

The advantages of associating shade trees in coffee agroforestry systems (AFS) are generally thought to be restricted mostly to poor soil and suboptimal ecological conditions for coffee cultivation whereas their role in optimal conditions remains controversial. Thus, the objective of this study was to investigate, under the optimal coffee cultivation conditions of the Central Valley of Costa Rica, the impact of Inga densiflora, a very common shade tree in Central America, on the microclimate, yield and vegetative development of shaded coffee in comparison to coffee monoculture (MC). Maximum temperature of shaded coffee leaves was reduced by up to 5°C relative to coffee leaf temperature in MC. The minimum air temperature at night was 0.5°C higher in AFS than air temperature in MC demonstrating the buffering effects of shade trees. As judged by the lower relative extractable water (REW) in the deep soil layers during the dry season, water use in AFS was higher than in MC. Nevertheless, competition for water between coffee and associated trees was assumed to be limited as REW in the 0-150 cm soil layer was always higher than 0.3 in shaded coffee compared to 0.4 in monoculture. Coffee production was quite similar in both systems during the establishment of shade trees, however a yield decrease of 30% was observed in AFS compared to MC with a decrease in radiation transmittance to less than 40% during the latter years in the absence of an adequate shade tree pruning. As a result of the high contribution (60%) of shade trees to overall biomass, permanent aerial biomass accumulation in AFS amounted to two times the biomass accumulated in MC after 7 years. Thus provided an adequate pruning, Inga-shaded plantations appeared more advantageous than MC in optimal conditions, especially considering the fact that coffee AFS provides high quality coffee, farmers' revenue diversification and environmental benefits.

The coffee rust crises in Colombia and Central America (2008–2013): impacts, plausible causes and proposed solutions

“…Microclimates in these systems vary widely. Air and leaf temperatures are reduced by shade (by around 6°C compared with full sun in certain cases) whereas relative humidity and leaf wetness are increased (Barradas and Fanjul 1986;Siles et al 2010;Lopez-Bravo et al 2012). In a specific climatic area, very different behaviours of coffee rust at the plot scale are therefore expected.…”

Root distribution and water use in coffee shaded with Tabebuia rosea Bertol. and Simarouba glauca DC. compared to full sun coffee in sub-optimal environmental conditions

“…In optimal conditions for coffee cultivation in Costa Rica no competition for water was found when shaded with Eucalyptus deglupta (Schaller et al 2003) or Inga densiflora (Siles et al 2009). However reports on coffee and tropical timber tree interactions in sub-optimal environmental conditions are few.…”

Modelling the hydrological behaviour of a coffee agroforestry basin in Costa Rica

“…Woody plants and, in particular, agroforestry (AF) systems associating shade trees and perennial crops with deep root systems, are assumed to enhance these HES in comparison to traditional intensive cropping systems (Siles et al, 2010a;Ataroff and Monasterio, 1997;Vaast et al, 2005). Costa Rica is renowned as a promoter of HES by charging water users for the HES they receive from land owners (e.g.…”