Regularidade de distribuição de sementes e de fertilizantes em semeadoras para plantio direto.

Abstract

This study aimed at assessing direct drills available in the Brazilian market as to their uniform distribution of seeds and fertilizers. The tests were carried out under two speeds of seeding during 1993 and 1994 on corn stubble in the winter evaluations and on rolled oats in the summer evaluations. An experimental design of blocks at randomwith split plots was used, in which the main plots were the seeders and the subplots the speeds of seeding, with three replicates. Concerning the regular distribution of seeds, the performance of the machines differed significantly (P < 0.01) both for wheat and soybeans seeders. For the wheat crop the seeders equipped with helical channeled rotor performed better than the remaining machines and simi-larly among themselves. For the soybean crop a seeder equipped with cell horizon-tal disc performed outstandingly. The best regular distribution of fertilizers was foundin the drills with a helical channeled rotor and endless screw both for wheat and soybean. The speed of seeding had a significant effect on fertilizer distribution only, reducing the flow as speed was in - creased.