Desempenho agronômico da soja : influência da velocidade de semeadura e do tratamento químico e biológico das sementes

Abstract

Brazil has consolidated itself among the main grain producers in the world, through the application of technologies capable of optimizing increasingly sustainable production, through the rational use of inputs. Seed treatment is a technique widely used in the Brazilian soybean crop, largely with chemical fungicides and more recently biological products, aiming to protect the seeds in the soil soon after sowing, an operation that deserves attention, because when performed improperly, as in high speed travel, can compromise the distribution of seeds, harming the emergence and establishment of the crop. In view of this, the objective of this work was to evaluate the effectiveness of the treatment of soybean seeds with the use of chemical and biological fungicide in the sanitary and physiological quality, as well as in the development, productive potential and quality of the soybean seed when sowing is carried out in different speeds. The experiment was carried out in three stages, initially, the sanitary and physiological quality of soybean seeds of the cultivar NA 5909 RR was evaluated when receiving different fungicides, adopting a completely randomized design. In the second stage, the sowing of these seeds was carried out at different displacement speeds (3,5; 5,0; 6,5; 8,0 km h-1 ), in a bi-factorial scheme in sub-divided plots (3 products x 4 speeds), with four replications, using a biological fungicide, a chemical fungicide and a control without product. In this stage, the quality of seed distribution, initial development and yield components of the crop were evaluated. Finally, in the third stage, the seeds produced were taken to the laboratory for analysis of their quality, following the experimental design of the previous stage. Data were submitted to analysis of variance and, when significant, the effects of seed treatments were compared by Tukey's test, while regression analysis was performed for the averages of the effect of displacement speeds. It was possible to observe the effect of the products applied to the seeds on their development potential, with beneficial effects of both fungicides on pathogen control and initial development. It is recommended that during the sowing operation, the displacement speed is less than 6.0 km h-1 , due to better results in the distribution and establishment of the plants, reflecting in the productive potential of the soybean fields, even without substantially affecting the quality of the seeds produced, considering that they presented good results of physiological quality in the tests carried out.