Periodicidade de crescimento do cafeeiro (Coffea arabica l.) em diferentes tensões de irrigação em duas densidades de plantio

Abstract

Brazilian coffee farmers are constantly in need of increasing their profits to survive to a market that is becoming even more competitive. The periodicity of coffee tree vegetative growth is associated with a number of factors, such as: temperature, photoperiod and irradiance, water and nutrients supply, and reproductive growth. If temperature is favorable, coffee tree growth may be affected by water supply. The need of new research studies providing scientific grounds for adequate coffee tree irrigation management was the motivation for this study, that was intended to analyze, at two planting densities (2500 plants.ha-1 e 10000 plants.ha-1), vegetative growth evolution of coffee tree (Rubi MG-1192) submitted to different irrigation trigger tensions (20, 60, 100, 140 kPa and without irrigation). For the crop first four years (2001 to 2005), vegetative growths observed at drought and rainy periods were compared. Evaluated growth parameters were: plant height, canopy diameter and number of primary plagiotropic branches. For both planting densities, as indicated by all evaluated growth parameters, irrigation provides higher vegetative growth. During dry periods, plant submitted to low irrigation trigger tension values (20 and 60 kPa) presented higher growth than plants submitted to higher irrigation trigger tension values. During rainy periods, there were no differences among vegetative growth of plants submitted to different irrigation criteria. This fact indicates that during rainy periods irrigation criteria based on soil water trigger tension values higher than 60 kPa are recommended, because they save more water and energy. Higher growth rates in plant height, and canopy diameter were observed during rainy periods and. For the 2500 plants.ha-1 treatment, higher growth rate in plagiotropic branche number was observed during dry periods. For the 1000 plants.ha-1 treatment, there were no differences on plagiotropic branches number growth rate during dry and rainy periods.