Beneficiamento de sementes de soja na mesa de gravidade: qualidade das frações e do repasse

Abstract

The objective of the present work was to verify the physical and physiological quality of soybean seeds after the treatment at the gravity table and to determine the characteristics of the transfer fraction after passing through the gravity table again. A batch of seeds, cultivar BMX Potencia RR, from the Abelardo Luz field was used. The seeds were harvested from March 2012, pre-cleaned, dried and stored in a big bag with a humidity of 13.2% to date In August. Initially, the seeds were benefited in air machine and sieves, spiral separator, classifier, gravity table (Rota rectangular, model RT 80 with capacity of 3.2 tons / hour). Samples were collected dividing the terminal axis of the discharge into 10 equal parts of width 10 cm each, which were the treatments denominated fractions 1 to 10, with 1 being the highest part and 10 being the lowest part of the discharge zone. After the collection, the medial parts of the table (fractions 5 to 7) were separated that formed the fraction to be transferred by the table dividing the axis of discharge of the seeds in 10 equal parts of 10 cm each, constituting the denominated treatments of fractions 11 to 20. Samples were collected following a similar procedure from the first 10 fractions. The seeds were submitted to the following evaluations: germination, accelerated aging, tetrazolium, thousand seed weight and mechanical damage. It is concluded that: a) the gravity table allows the separation of soybean seeds into classes in terms of physical and physiological quality; B) the fractions of higher physical and physiological quality represent 80% of the seed lot when benefited at the gravity table; C) the physical and physiological quality of the transfer fraction on the gravity table represents on average 10% of the lot and allows a recovery of up to 80%; D) it is possible to significantly decrease the percentage of soybean seeds with mechanical damage at the lowest positions of the discharge shaft of the gravity table.