Influência da velocidade de deslocamento na semeadura do milho, utilizando uma semeadora-adubadora, adaptada as condições de solos de várzea no estado do Rio Grande do Sul

Abstract

The objective of this work was to evaluate the influence of five different displacement speeds at sowing on maize crops, using a fertilizer-seeder adapted to down land conditions at Rio Grande do Sul state. The experiment was conducted in an experimental area located in a private farm (Agropecuária Busatto) at the city of Itaqui-RS, dusing the period of august september of 2013. The experimental was conduted in a randomized block with four replications and five treatments, each one of the treatments correspond to the respective displacement speeds of 2; 4; 6; 8 and 10 km h-¹. The seeder-fertilizer used was a "Hyper Plus ridge seeder" that has a kit compounded by 3 moldboard plows, responsible for the formation of micro ridges between the sowing lines. To pull the seeder, a John Deere 7575 tractor powered by a 103 KW engine was used. Variable enideraled factors were the seed deposition depth, uniformity and longitudinal distribution of the seeds considering the acceptable spacing between plants, multiple seed spreading and flawed row levels, level of exposed seeds, furrow depth between the micro ridges and the operational capacity of the mechanized set. The data obtained was submitted to ANOVA test, the rates compared by Tukey test with a 5% error probability and regression analysis was used to identify the tendency of the variables in relation to the increase of the displacement speed. According to the results, a variation of 16 mm from the highest to the lowest speeds was observed respectively in relation to the seed deposition depth, the uniformity and longitudinal distribution of the seeds. Analyzing the obtained results, it is possible to affirm that the micro ridger seeder-fertilizer, has achieved a great performance at the speed of 2 km h-¹, good performance for the speeds of 4 and 6 km h-¹ and regular at the speeds of 8 and 10 km h-¹. As the displacement speed increases, a rise of 2.042%, in addition to the multiple seed spreading and 3.069% to flawed row spacing were observed. For the level of exposed seeds, the speed of 10 km h-¹, showed the highest rates. The furrow depth between the ridges showed a 25.35 mm difference between the lowest and highest displacement speeds. The operational capacity showed an increase of 0.47 ha h-¹, for each speed increase. Therefore evaluation of the tractor/seeder set performance conclusive that the displacement speed has influence on the performance of the micro ridger seeder-fertilizer for maize sowing in down land conditions. The proper speed for the operation at such conditions is 6 km h-¹.