Padronização de sementes de soja em peneiras de furos redondo e oblongo com variação no fluxo de alimentação

Abstract

In sowing of soybean seeds it is essential to establish a good stand of plants with good distribution and arrangement. To assure the best performance in the planters seeds are graded for size to correct fulfilling of the disc perforations. The objective of the present work was to evaluate the efficiency of grading soybean seeds cultivars CD 204 and CD 206 over round and oblong hole screens of a grader machine Reinke® located at the Agricultural Mix Cooperative Duovizinhense Ltda, Paraná state, with feeding flows of 3,2; 2,7; 1,8 and 1.1 tons per hour in the machine. The seeds were conditioned through an ASC and a gravity table before grading. Round hole screens were 8; 7 and 6 mm and oblong holes 7X19; 6X19 and 5X19 mm. The seeds over screens 8 and 7X19 mm and in the deep blind were discarded. Sampling was done in each pipe for a period of 30 seconds for each screen and each feeding flow in the machine. To evaluate screen efficiency, each sample was passed over three hand screens per one minute to determine the retention percentage. The results showed that soybean seed grading through 7 mm round hole screen was more efficient in the 2,7 tons per hour flow; in the same flow, the efficiency of the 6 mm round hole screen was superior than the 6X19 mm oblong hole; and only grading soybean seeds through the 5X19 oblong hole screen was inside of the tolerance of retention larger seeds of 3%.