Reduction of frost damage to coffee trees under agroforestry systems

Abstract

Frosts affect coffee production in Brazil, with effects on commodity prices around the world. Agroforestry systems are strategies to reduce the effects of frost on coffee trees. To date, this study has evaluated the largest number of tree species in coffee tree AFSs in Brazil in the same experiment. The objective was to identify tree species that can protect coffee trees against frost damage in agroforestry systems. The study was conducted in Londrina, Paraná, Brazil. Each treatment consisted of coffee trees associated with one of the following tree species: Moringa oleifera, Croton floribundus, Trema micrantha, Gliricidia sepium, Senna macranthera, Heliocarpus popayanensis, and Mimosa scabrella, as well as a control of coffee trees in monoculture. The experimental area was affected by frost that damaged the coffee plants fifteen months after planting. Immediately thereafter, the dendrometric characteristics of the trees were evaluated. After 30 days, the defoliation and mortality of the trees were evaluated. The phytometric characteristics of the coffee trees were evaluated 12 months after the frosts. Six of the seven tree species were evaluated for the first time for their ability to protect coffee trees against frost. Even at an early stage of development, T. micrantha and H. popayanensis provided increased protection of coffee trees, reducing the defoliation and mortality of coffee trees. The main protective factor was the canopy area of these species, which provided a high rate of tree cover. The development of coffee trees after frosts was favoured by the shading of the species, with the exception of M. scabrella. The AFSs with T. micrantha and H. popayanensis constitute an alternative that allows the mitigation of frost damage to coffee plants in regions prone to this climatic stress, reducing defoliation and mortality.