ABSTRACT Operational speed influences the soil preparation quality, the first established according to the working set performance and its traction capacity. The experiment's objective is to determine the influence of working speed on energy and operational performance of an agricultural tractor with Full-Powershift transmission when performing a harrowing operation. We conducted the experiment using lines, in a randomized block design. It had four operational soil preparation speeds, with seven repetitions, totaling 28 experimental units. We measured the following parameters per worked area: slipping, engine rotation, specific and per hour fuel consumption, strength, power, and yield on the drawbar and operating speed. Additionally, we analyzed soil profilometry parameters concerning the mobilized area and working thickness. We also evaluated the variance of the collected data and, when significant, submitted it to a regression test. The data showed that higher operating speeds result in greater operational performance and reduction of the energy demand of the mechanized set under study. In addition, this increase doesn't have a beneficial effect on grid fluctuation, not affecting the quality of soil preparation.

ABSTRACT The objective of this study was to determine the effect of the longitudinal distance between a cutting disc and a fertilizer furrow opener on the operational performance of the furrow opener working at different forward speeds during soil mobilization. The soil in the experimental area was classified as Typic Hapludalf with a loam soil texture. The experiment involved 24 treatment combinations in a 2 × 3 × 4 factorial scheme. These combinations were formed by the interaction of the following factors: furrow opening mechanisms, longitudinal distance from the center of the cutting mechanism to center of the furrow opener, and forward speeds. The effects of the tools on the soil mobilization variables were characterized in three phases: analysis of the natural profile and elevation and mobilization of the soil using a microprofilometer. A statistical analysis of variance was performed on the acquired data and the significance of the factors was verified using an F test. The furrow opener factor significantly substantially influenced all variables, whereas the distance significantly modified only the soil swelling and elevated soil area, with a reduction of approximately 30% in this variable when separating the mechanisms by an additional meter. Likewise, for a hoe furrow opener, the speed significantly influenced only the maximum depth of the furrow. Hence, we recommend the installation of fertilizer furrow openers close to the cutting mechanisms to increase the quality of the furrows produced in seeding operations using the direct planting system.

RESUMO A correta distribuição longitudinal das sementes pela máquina semeadora é uma das características que mais contribuem para a obtenção de estande adequado de plantas e para a boa produtividade das culturas. Objetivou-se, neste trabalho, avaliar a distribuição longitudinal de sementes de milho por diferentes tipos de tubos condutores, combinados com um dosador de disco alveolado horizontal e um pneumático, variando-se a densidade de semeadura. O experimento foi conduzido em laboratório utilizando uma bancada de ensaio de dosadores de sementes. Os tratamentos consistiram da combinação de dois dosadores, seis tubos condutores e quatro velocidades periféricas do disco dosador, correspondentes às densidades de 60, 70, 80 e 90 mil sementes de milho por hectare e foram organizados em um esquema trifatorial, com quatro repetições. Ao aumentar a densidade de semeadura para uma mesma velocidade de deslocamento, houve redução do percentual de espaçamentos aceitáveis este efeito mais acentuado quando utilizados tubos condutores com pequeno diâmetro e perfil reto.

ABSTRACT The correct longitudinal distribution of seeds by the seeder machine is one of the features that most contributes to obtain an adequate plant stand and good crop yield. The objective of this study was to evaluate the longitudinal distribution of corn seeds by seed conductor tube types, combined with a horizontal perforated disc and a pneumatic meter, altering the seeding density rate. The experiment was conducted in a laboratory using a seed meter test bench. Treatments were a combination of two seed meters, six conductor tubes and four peripheral speeds for the meter disc, corresponding to densities of 60, 70, 80 and 90 thousand corn seeds per hectare and were organized in a three-factor scheme with four repetitions. By increasing the seeding rate into the same ground speed, there was a reduction in the percentage of acceptable spacing, this effect being more pronounced when conductor tubes with a small diameter and straight profile were used.

O objetivo foi avaliar o desempenho operacional quanto ao requerimento de tração, consumo energético e eficiência de trabalho de associações entre elementos de corte dos resíduos culturais e de rompedores do solo, em função da velocidade de deslocamento. Este trabalho foi realizado em propriedade agrícola situada no município de Santa Maria (RS), em solo classificado como Argissolo Vermelho e textura francoarenosa. O experimento foi composto por 24 combinações de tratamentos, em um esquema fatorial de 2x3x4. Estes foram obtidos pela interação dos fatores sulcadores (haste e disco), discos de corte (sem disco, liso e ondulado) e velocidades (1,11; 1,67; 2,22 e 2,78 m s-1). Os dados de desempenho do trator foram adquiridos com a utilização de instrumentação eletrônica. As associações entre sulcador e disco apresentaram melhor desempenho nas velocidades de 1,11 e 1,67 m s-1 por exigirem menor força de tração e consumo de combustível. Além disso, o uso de discos permitiu uma redução da ampliação da força de tração quando a velocidade passou de 1,11 para 2,78 m s-1. A haste exigiu maior demanda de tração do que os discos desencontrados, e ambos, ao serem combinados com os discos de corte, tiveram suas demandas aumentadas. Outrossim, a mobilização do solo não foi influenciada pela velocidade.

The objective was to evaluate tractor operating performance regarding traction application, energy consumption and working efficiency in association of crop residue cutting implements and soil breakers as the travelling speed. Experiment was performed at a farm in Santa Maria (RS), Brazil. Local soil was classified as Red Ultisol with sandy loam texture. The experiment consisted of 24 treatment combinations in a 2x3x4 factorial scheme. The combinations were composed by interactions furrowers (furrow opener fixed and rotary), cutting disks (without disk, plain disk, and undulating disk) and travelling speeds (1.11, 1.67, 2.22 and 2.78 m s-1). Tractor performance data were acquired through electronic instrumentation. Furrower and cutting disk association had improved performance at speeds of 1.11 and 1.67 m s-1 for requiring less traction and fuel consumption. Furthermore, disks reduced required traction at speed range of 1.11 to 2.78 m s-1. On the other hand, furrow opener device demanded higher tractions than mismatched disks; and both of them combined with cutting disks had increased demand too. Likewise, soil mobilization soil was not influenced by speed.

O presente trabalho teve por objetivo desenvolver uma ferramenta capaz de expressar matematicamente a taxa de aplicação de fertilizante em função do tipo de dosador, inclinação longitudinal, inclinação transversal e velocidade de acionamento do dosador. Foram utilizados três dosadores helicoidais com dispositivos de descarga por gravidade, transbordo transversal e transbordo lateral e adotado o delineamento composto central rotacional, com três variáveis independentes. A partir dos modelos ajustados constatou-se que os dispositivos de descarga apresentam diferentes implicações em relação aos efeitos de inclinações longitudinais e transversais de operação. O dosador com descarga por gravidade demonstrou maior sensibilidade quanto aos efeitos das inclinações de operação e o dosador com descarga por transbordo lateral demonstrou menor sensibilidade. A análise de regressão demonstrou que todos os modelos foram significativos, sendo encontrados baixos erros relativos e absolutos dos dados previstos pelos modelos.

This study aimed to develop a tool capable of expressing mathematically the rate of fertilizer application depending on the type of distributor, longitudinal slope, cross slope and driving speed of distributor. Three helical distributors with gravity discharge, transverse discharge through overflow and side discharge through overflow were used. The central composite rotational design with three independent variables was adopted. From the adjusted models it was found that the discharge devices have different implications for the effects of longitudinal and transversal slopes of operation. The distributor with gravity discharge showed greater sensitivity to the effects of slopes and the distributor side discharge through overflow showed lower sensitivity. Regression analysis showed that all models were significant, and found low relative and absolute errors of the data predicted by the models.

A redução das janelas de semeadura e a intensificação da produção no sistema de semeadura direta impulsionaram o aumento na frequência de utilização de máquinas, provocando compactação pelo tráfego. A compactação, além de prejudicar o desenvolvimento das raízes das plantas, aumenta a demanda de potência dos implementos justificando a utilização de escarificadores para a descompactação do solo. Avaliou-se o desempenho de dois escarificadores (Haste + ponteira), sendo um comercial e um experimental, com vistas a entender a operação de escarificação quando adaptada ao sistema de semeadura direta, utilizando como parâmetros variáveis energéticas e de solo. O elemento descompactador experimental teve um desempenho superior ao comercial nas principais variáveis estudadas, tais como consumo de combustível, potência e força de tração. Quando à frente dos elementos descompactadores o disco de corte não alterou a força de tração mas reduziu o consumo de combustível e a potência. O aumento da velocidade proporcionou incremento da força de tração, potência e consumo de combustível.

Reduction in sowing period and intensification of production in no-tillage system, promoted an increase in the frequency of the use of machines and implements, causing compaction of soil due to traffic. The compaction, in addition to affecting the development of plant roots, increases the power demand of the implements, justifying the use of chisel plows for soil decompactation. The performance of two chisel plows (Shank + tip), one commercial and one experimental, was evaluated to understand the chiseling (scarification) operation adapted to no-tillage system and compare two chisel plows, using as parameters such as energy and soil variables. The experimental decompactation element performed better in comparison to commercial, in key variables, such as fuel consumption, power and traction force. When installed ahead of descompactation elements the cutting disc did not alter the traction force and reduced the fuel consumption and power. The increase in the speed provided an increase in traction force, power and fuel consumption.