Qualidade da semeadura da soja em função da velocidade e do sistema de distribuição

Abstract

Soybean is a species that plasticity, that is, is able to adjust the different conditions to which it is exposed, and these environmental or management by morphological changes and yield components. Present study aimed to evaluate the influence of sowing speed and distribution seed systems (with distribution of honeycomb horizontal disk and pneumatic) at seeding quality. Cv soybean seeds were used Brasmax Ponta IPRO (BMX 7166 RSF IPRO) belonging to maturity group 6.6, having preferential seeding period for the region from October 25 to December 10. To pull the seeder honeycomb disk, was used tractor John Deere Model 8320R ™, the year 2011 with 320 horsepower. For the seeder with pneumatic delivery system, we used the 8335R Tractor John Deere ™, 2014, with 335 horsepower. Five different speeds of seeding were used, which were: 4, 5, 6, 8 and 10 km h-1. The evaluations were: field emergence, distribution uniformity, dominated plants, grain yield, mass of thousand seeds (mms), uniformity test (retention sieve). The resulting data were submitted to variance analysis and when significant at 5%, the mean seeders were compared using the Tukey test and speeds represented by orthogonal polynomials. It follows that Pneumatic seeder resulted in lower seedling emergence 4 and 5 km h-1 for the disc planter honeycomb horizontal.A speed influence the coefficient of variation of spacings so that with increasing speed seeding, increased uniformity of the spacing between plantas. Both planters does not effect satisfactorily the distribution of seeds, with only 10% of plants from sowing with disc and 15% of plants sowm by pneumatic sowing are at the desired spacing.