DENSIDADE DO SOLO NO AMBIENTE SOLO-SEMENTE E VELOCIDADE DE EMERGÊNCIA EM SISTEMA DE

SUMMARY : SOIL DENSITY IN THE SOIL-SEED ENVIRONMENT ANDEMERGENCE SPEED IN MAIZE PLANTING SYSTEM The microenvironment near the seed is directly affected by the type of mechanism offurrow opening and the soil compacting element. This study was therefore carried out toevaluate the soil density close to the seed in a no-till system using computerized tomography.The experiment was set up in a split-plot design in which the plots consisted of three soilwater contents (0.22; 0.28; and 0.34 kg kg -1 ), and the subplots of two mechanisms for furrowopening (stub runner and double disk-type). The sub-subplots consisted of two compactingelement types (rubber and plain) in a maize crop. The experiment was in a randomizedblock design with three replications. Some undisturbed soil samples corresponding to aplanting spot in the planting row were removed to establish tomographies with millimetricalresolution for the determination of soil density. The maximum, minimum and average soildensities were determined at the point where the seed had been placed in the undisturbedblock. The results showed that the treatments had no significant influence on the values ofemergence speed index, or on the minimum density measured by the tomograph. Thedouble-disk mechanism led to higher values of densities measured by tomography, bothmean and maximum, as well as lower emergence. The use of a rubber compacting elementresulted in lower seed pressure a greater contact area with the soil. Computerizedtomography appeared to be an adequate and efficient method to determine soil density inthe seed area.Index terms: computerized tomography, no-till planting, furrowers, compaction, maizecultivation, germination.