Efecto de la sombra arbórea sobre indicadores productivos en un Sistema Agroforestal (SAF) con café en el cantón Santa Ana de la provincia de Manabí

Abstract

The experiment was carried out on a farm in the Santa Ana canton, south-central region of the province of Manabí, Ecuador, located in a mountainous area, at about 300 meters above sea level. Coffee (Coffea arabica, sp) production is carried out in a context of peasant family agriculture, using an agroforestry system with coffee trees of the Sarchimor variety planted at 1.6 x 2.0 m, interspersed with tree species typical of the dry forest (70 trees including forest and fruit species), with manual weed control, without fertilization or irrigation, and without phytosanitary control or shade regulation. In this scenario, and during an experimental period of 343 days (03/08/2022 - 07/07/2023), some phenological variables and indicators of chlorophyll content in leaves (SPAD Units) were compared in 35 coffee trees maintained in 3 levels of shade (S1: 10 - 30%; S2: 31 - 50%; S3: 51 - 60%) and a control at full sun exposure S0. It is concluded that the effects of shade on the growth of branches and SPAD units were not clearly convincing, although the effects of shade on the decrease in trunk diameter (D) and bush height (H) were clearly convincing. These effects were not modified by time (T), but the latter factor did influence total lower stratum branches at any shade level, which decreased in number with each measurement. These results are attributed to the insufficient production of photoassimilates under shade conditions, which is manifested first in roots and trunk to preserve the growth of the branches, and finally that of the fruits, whose number was higher in those exposed to shade levels equal to or higher than 50%.