Colheita, beneficiamento e tratamento de sementes de soja visando alta qualidade

Abstract

The production of high quality seeds represents one of the main factors for the success of the soybean crop, however, this is dependent on all stages of the seed production system, from sowing, cultural practices, climatic conditions, harvesting techniques, seed conditioning, storage conditions and treatment. An effective quality control is required with technologies that provide efficient production. Thus, three experiments were conducted, involving factors since harvesting, seed conditioning, until soybean seeds treatment. The first experiment, aimed to evaluate the incidence of mechanical damages, moisture damages and the physiological and sanitary quality of soybean seeds harvested with different methodologies and water contents. Seeds harvesting with 13% of water content causes higher incidences of mechanical damage and deterioration by moisture in the seeds, regardless method is used. The severity of these damages is intensified with storage. At mechanically harvested seeds, with the axial threshing system, at 19% of humidity, it is observed better quality in relation to seeds harvested with 13%. Harvest delay from 19% to 13% favors the fungal incidence, mainly of Fusarium spp. The incidence of mechanical and moisture damages depreciated the seed physiological quality and favored the incidence of fungi. The second experiment aimed to evaluate the incidence of mechanical damages and the physiological quality throughout the seed conditioning as a function of the size of the soybean seeds. It was verified, in an industrial conditioning, higher incidences of mechanical damage and lower physiological quality in larger seeds. Lots with higher apparent specific mass present higher physiological quality. Difference of 3% in specific mass analyzes between soybean seeds from the upper and lower sections of the densimetric table is an adjustment that stratifies in terms of physiological quality. The density table is efficient in separating seeds with mechanical damage and different levels of vigor and germination. The size of seeds does not affect the incidence of deterioration by moisture and the density table is not efficient to reduce this defect in the lot. At the third experiment aimed to evaluate the influence of soybean seed treatment technologies, machines and processes with industrial and On Farm treaters, about the occurrence of mechanical damage and the functional quality of the treatment. Soybean seed treatment in industrial batch or continuous flow treatment machine, with no difference between these technologies, ensures better seed coverage, greater dose assertiveness, lower dust-off and lower incidence of mechanical damage in relation to the application technology OnFarm. Digital processing of high-resolution images is efficient for quantification of soybean seed coating by phytosanitary products. Seed coverage is directly related to dose assertiveness.