Otimização do uso da água e de nutrientes na produção e no manejo da cercosporiose do cafeeiro

Abstract

Brown eye spot (BES) is a major coffee disease caused by the fungi Cercospora coffeicola. Factors like water stress and nutritional imbalance may contribute to the disease progress. Recently, the demand for agronomical technics which can minimize the damage caused by BES is growing. Consequently, the improvement of crop yields in a sustainable system. Thus, the aim of this study was to evaluate the effect of different soil coverings, fertilizes and soil conditioners to manage BES in Mundo Novo 379-19 coffee cultivar, susceptible to this disease. The factors studied were arranged in a 3x2x5 factorial scheme, totalizing 30 treatments, allocated in split-split plot arrangements. The experiment was arranged in a randomized block desing with three replicates. The plots were composed by the soil coverings, poliethylene film, Urochloa decumbens and no-covering. The subplots were composed by conventional and controlled-release fertilizer. The sub-subplots were composed by conditioners, organic compound, coffee husk, agricultural gypsum, hydrorretentor polymer and witness. In the next step, leaf and berry BES, total leaf area, soil moisture, plant growth, leaf area index, soil fertility and yields were evaluated. The data obtained were submitted to variance analysis and Scott-Knott test 5% probability. The results from BES medium incidence, total leaf area and soil humidity were plotted in progress curves, together with medium weather variables. Signal grass and soil conditioners, organic compost and coffee husk, promoted higher soil moisture and improved soil chemical attributes, reducing leaf and fruit BES and defoliation. Despite the high soil moisture in the polyethylene film and increase in vegetative growth, this soil covering provided a higher incidence and severity of BES in fruit, leaf and lower foliage. Controlled-release fertilizer, even without significant reduction of BES, allowed improvements in vegetative growth and foliage. The agricultural gypsum, even with high productivity, caused nutritional imbalances and possible nutrient leaching, contributing to the increase of BES and causing reduction of 72 to 81% in the leaf area index of coffee crop.