RESUMO:O objetivo foi avaliar o desempenho operacional quanto ao requerimento de tração, consumo energético e eficiência de trabalho de associações entre eleme ntos 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 comb inados com os discos de corte, tiveram suas demandas aumentadas. Outrossim, a mobilização do solo não foi influenciada pela velocidade. PALAVRAS-CHAVE:Semeadora-adubadora, Relação máquina-solo, Ensaio de máquinas agrícolas, Haste sulcadora, Discos duplos desencontrados, Mecanismo de corte. OPERATING PERFORMANCE OF FURROWERS AND CUTTING DISKS ASSOCIATION FOR NO-TILLAGE SYSTEM ABSTRACT:The objective was to evaluate tractor operating performance regarding traction application, energy consumption and work ing efficiency in association of crop residue cutting implements and soil breakers as the travelling speed. Experiment was performed at a farm in Sa nta 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.

The present study evaluated the effect of different associations between coulters and fertilizer furrow openers on soil disturbance, furrow depth and width, according to forward speed. The study was conducted on a farm in Santa Maria (Brazil/RS), in soil classified as sandy loam Ultisol. The experiment consisted of 24 combinations of treatments with three replications in a 2×3×4 factorial experiment. The combinations were formed by the interaction of the factors including: two types of furrow openers (hoe and double-disc), three types of coulters (no-coulter, smooth and offset fluted) and four levels of forward speed (1.11, 1.67, 2.22 and 2.78 m/s). Soil elevation and soil disturbance area profiles were obtained with the use of a micro profilometer, and disturbance values were calculated with the aid of computer software program Auto Cad. The disturbance area was not affected by speed; it was greater when using the hoe opener, and in association with the offset fluted coulter. Speed was inversely proportional to the depth of the furrows made by the hoe opener. Furthermore, the hoe caused the greatest furrow width (0.26 m) in comparison with the double-disc (0.24 m). The use of different coulters associated with furrow openers increased this variable (0.23 m for the no-coulter condition, 0.25 m with smooth and 0.26 m with offset fluted). The use of coulters combined with furrow openers reduces soil swelling, in approximately 8% for the smooth and 20% for the offset fluted.

A B S T R A C TThe 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.

R E S U M OO 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.Mathematical models for selection of helical fertilizer metering mechanism with different fertilizer discharge A B S T R A C TThis 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. Palavras-chave:semeadora adubadora taxa de aplicação de fertilizantes mecanização agrícola

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