Performance of Planter Shanks in the Soil Mobilization in No-Tillage System.

In no-tillage system (NTS) the producer must know the ideal tool for each condition that the soil can provide. At the moment of sowing, the function of the planter shank is unpack and disturb the soil, but if the shank is not provide specific geometry for a specific soil condition, this could interfere on the soil opening angle, causing the compaction due the mirroring formation on the walls of the furrow. The aim of this study was to analyze three planter shanks in different working depths, evaluating the area of disturbed soil, the tractor performance and yield components of corn crop. The experiment was conducted in areas of the FCAV, UNESP Univ Estadual Paulista, Jaboticabal city, São Paulo State, Brazil and the experimental soil of this area is classified as typical eutroferric Red Latosol. Was utilized a completely randomized design with factorial scheme 3 x 5 being three shanks (S1, S2 and S3) and five depths, with four replications. The variables analyzed were:  initial and final stand, crop yield, plant dry matter, force and power in the drawbar, fuel consumption, soil mechanic resistance to penetration, longitudinal distribution of seed, average number of the days to seedlings emergence, width and depth of the furrow, disturbed area of the furrow (soil mobilization), specific force and specific power. There was a significant difference between shanks. For the depths there was a crescent regression, wherein when the shanks deepened, they caused an increase in the soil mobilization, consequently the same was the furrow width. According to the results, it is not recommended to work with depths less than 10 cm and neither work with S2.