Modelagem da alocação de biomassa em cafeeiros em resposta à variabilidade climática

Abstract

Coffee plant is subject to climatic adversities throughout the year, which can affect the development and productivity of the crop. The instability in the amount and distribution of rainfall and the greater occurrence of periods of drought are the most worrying cases for the coffee production in Brazil. Although there is great uncertainty about how each producing region can be affected, it is possible to predict some responses in the typical patterns of carbon allocation and secondary growth of coffee trees. In this work, we sought to assess the influence of climatic conditions in the secondary growth of coffee plants under field conditions, as well as see how the allocation is affected at different levels (leaves, fruit and stems) in the face of environmental variations. The work was conducted in the regions of Lavras and Varginha, Minas Gerais, using the Coffea arabica L. specie, cultivars Mundo Novo and Arara, evaluated in the 2010-2017 period; employing the analysis of the structure of plant growth rings through dendrochronological methods to determine the radial annual growth rate of trees and correlate them with the climatic characteristics of the region, using a statistical correlation analysis of Pearson. A quadratic polynomial model was adjusted to describe the relationship between radial increment and the main climate variables (precipitation and temperature), and the logistic regression model to describe the relationship between the increment in height and radial increment. With the results it can be concluded that in the period and regions evaluated, the increase in minimum temperature was the factor that had the greatest influence on the increase in the annual secondary growth rate of coffee trees. A better data set is needed to establish a direct relationship between secondary growth and carbon allocation, which allows for the evaluation of changes in the allocation patterns in coffee trees at different levels in years with climatic changes.