Production and Vegetative Development of Coffee Tress Grown under Solar Radiation and Fertilization Levels, During Years of High and Low Yield

摘要

The objective of the experiment was to evaluate the effect of the levels of photosynthetically active radiation (PAR) and nutrients on the production and vegetative characteristics of coffee trees in years of high and low yield. The coffee trees werecovered, at the top and sides with shade screens (PAR reduction by 0, 16, 32 and 48%) and fertilized with either 100, 80,60 or 40% of the recommendation from 2001 on. In 2005 and 2006, the following characteristics were determined in per branch basis: number of total nodes, size of the internodes, number of productive nodes, number of leaves and leaf area, besides one leaf area and tree production. Besides these variables, the following characteristics were determined in 2005: specific leaf area, berrymass, number of berries per tree, leaf area per berry, size and uniformity of maturation of the berries. In 2006, a dry branch index was determined. There was not any effect of the fertilization on any characteristics evaluated. With the increment of shading, it was observed an increase in the length of the internodes, leaf area, leaf area per branch and specific leaf area. There was a reduction in the production per tree and number of berries per tree with the increase of shading. The trees under the highest level of shade presented heavier and bigger berries than the trees under full sun. The trees under 48% of shade presented late and uniform maturation. In 2005, the leaf area per berry was higher in more shaded trees. In 2006, these trees presentedfewer dead branches. The conclusions are: full sun condition results in coffee trees with shorter branches, a smaller leaf area per branch and smaller and thicker leaves. Shading favors the formation of fewer berries per tree and results in smaller production, although the berries are bigger and heavier. Coffee trees under high levels of shading present later ripening than the unshaded ones, although both conditions result in uniform berry ripening.