Desempenho de um sensor ativo de reflectância em função da altura e inclinação do sensor de medição e da aplicação de adubo nitrogenado em cobertura nas culturas de trigo e soja

Abstract

The Precision agriculture aims at rationalizing and applying the amount of inputs surely required in a farm in order to avoid wastes and increase profits for the producer. Thus, it is considered as an excellent alternative to increase yield and reduce the impact on the environment. Since nitrogen is the most input expensive input and the most difficult one to control, its measurement into canopy is generally a goal of applied studies. Among the existing technologies, evaluation of NDVI vegetation index is widely used. In this context, this study aimed at studying both the influence of an active reflectance sensor positioning on reading the normalized difference vegetation index (NDVI) and the impact of an additional application of N. It was observed that the height of such sensor positioning can influence the reading obtained depending on the stage and crop where it such reading is carried out, nevertheless, gradient does not affect directly the reading within the range established in this trial. And for nitrogen application, It was also observed some positive influence on NDVI response and on yield of such area cropped with wheat. In soybean, the influence was observed, with less than 2% gain in productivity.