FLUXOS DE ENERGIA RADIANTE EM CULTIVOS DE AMORA-PRETA ‘TUPY’

Abstract

The objective of this study was to determine the albedo and characterize the interference of winter pruning times on the partitioning of radiation fluxes in ‘Tupy’ blackberry crops. The experiment was conducted in a commercial orchard in the municipality of Morro Redondo, RS, Brazil, with pruning performed on July 18 (early), August 10 (conventional) and September 1 (late), 2016.  The stages of the phenological cycle with the highest accumulation of global solar radiation and net radiation were those from green berry to pink berry and from floral bud to open flower. From emergence to fruit maturity , the crops showed regularity in the amount of global solar radiation received, totaling 1392.1 MJ m^-2 (early), 1327 MJ m^-2 (conventional) and 1408.7 MJ m^-2 (late). On a cloudy day, the net shortwave radiation on blackberry cultivation followed the same reduction in global solar radiation, 85%, compared to the sunny day, while for the net longwave radiation this reduction was equal to 50% (conventional and early pruning) and to 60% (late). The albedo of ‘Tupy’ blackberry ranged from 0.22 to 0.23 and the net radiation on the crop represented 54% to 59% of the global solar radiation.