Alcir José Modolo

Furrow depth, soil disturbance area and draft force of a seeder-fertilizer at different seeding speeds

Este trabalho teve por objetivo avaliar a profundidade de sulco, area de solo mobilizada e a forca de tracao solicitada por uma semeadora-adubadora de precisao em sistema de plantio direto na cultura do milho, em razao da velocidade de deslocamento. O delineamento experimental foi em blocos ao acaso, com quatro repeticoes em arranjo fatorial 4 x 3, com 12 tratamentos, constituidos de quatro velocidades de deslocamento, obtidas pelos escalonamentos de marchas e de tres rotacoes do motor do trator. Durante a semeadura, monitoraram-se a velocidade de operacao, a rotacao do motor e a forca de tracao na barra. Apos a semeadura, foram avaliadas a profundidade do sulco e a area mobilizada de solo. Os resultados mostraram que: a profundidade do sulco foi influenciada pelo aumento na velocidade de operacao; a area mobilizada de solo aumentou em 41 % com a elevacao da velocidade de operacao; o requerimento de forca na barra de tracao, media, por linha de semeadura e por area mobilizada de solo diminuiu com o aumento da velocidade; e a forca media na barra de tracao por profundidade do sulco aumentou com o incremento da velocidade de operacao.

Efeito da compactação do solo sobre a emergência de plântulas de soja em sistema plantio direto

Objetivou-se no presente trabalho, estudar os efeitos da combinacao entre teores de agua do solo e cargas aplicadas pela roda compactadora da semeadora-adubadora sobre a emergencia de plântulas de soja, em sistema plantio direto. A resistencia mecânica do solo a penetracao foi determinada quinze dias apos a semeadura. O indice de velocidade de emergencia foi determinado pela contagem das plântulas, sendo realizada diariamente ate que o numero de plântulas emergidas se apresentasse constante por tres dias consecutivos. O maior indice de velocidade de emergencia (IVE) ocorreu no teor de agua igual a 0,33 kg kg-1 e na carga de 86,21 N. A carga maxima de 140 N, aplicada pela roda compactadora sobre a semente, causou encrostamento superficial do solo, retardando a emergencia das plântulas.

Demanda energética de uma semeadora-adubadora em diferentes velocidades de deslocamento e rotações do motor

The operating speed of the tractor influences various aspects, including fuel consumption, operational capacity and sowing quality. This study aimed to assess the energy needs of a tractor-planter when sowing maize in a no-tillage system, according to its travel speed and the rotation speed of the motor shaft. The 12 treatments consisted of four travel speeds, obtained by staggering the gears, and three tractor-engine rotation speeds. During sowing, the speed of operation, engine speed, the traction force and hourly consumption of fuel were monitored. The results showed that the average power requirement on the drawbar per seeding row, groove depth, and worked area, increased with an increase in the operating speeds of the mechanism. Hourly fuel consumption went up with the increase in operating and engine-rotation speeds, being lowest at a speed of 1,500 rpm.

Força de tração e potência de uma semeadora em duas velocidades de deslocamento e duas profundidades de deposição de sementes

Traction and power required by a seed drill with 14 holes was evaluated in the oat (Avena strigosa L) seeding. The experiment was carried out in a Haplortox, in an area with mean slope of 0.03 m m-1. The experimental design consisted of four treatments (two seed deposition depths and two displacement speeds) with four repetitions, totaling sixteen experimental plots of 4 x 50 m (200 m2), in no tillage system on corn crop residue. It was concluded that the increase of the seeding depth of 1.97 cm to 2.68 cm, the draft requirement increased from 3.78 to 5.51 kN. The speed increase from 5.24 to 7.09 km h-1, caused an increase of 6,90% in the traction force of the drawbar.

Manejos de cobertura vegetal e velocidades de operação em condições de semeadura e produtividade de milho

The objective of this study was to evaluate quality parameters of sowing and the development and yield of maize sown in no tillage system under different vegetation managements and operating speeds of the seeder in the southwest region of the S tate of Parana. A split-plot design was used, where the plots were the vegetation management of the oat (oat latticed, rolled, chopped and desiccated) and split plot the operation speeds (4.5 and 7.0 km h-1), in a randomized block design with four replications. The spacing between plants, uniformity distribution of seed, sowing depth, rate of emergence, plant stand, soil area mobilized and yield of the crop were evaluated. The tabulated data were analysed by F test at 0.05 level of probability and in case of significance, the means were compared by Tukey test at 0.05 probability level. It was concluded that the best seed distribution was observed at lower speed and the mean productivity of the crop was not affected by treatments. The management of vegetation was not effective in improving conditions for sowing.

Desenvolvimento inicial e produtividade da cultura do milho no sistema de integração lavoura-pecuária

A integracao lavoura-pecuaria pode ser definida como o sistema que integra duas atividades, visando a maximizar racionalmente o uso da terra e a minimizar os custos de producao. Objetivou-se, com este trabalho, avaliar os efeitos de diferentes alturas remanescentes de pastagem e de mecanismos sulcadores sobre o desenvolvimento inicial e a produtividade da cultura do milho semeado em sequencia. Os tratamentos foram compostos pela combinacao de quatro intensidades de pastagem (0,05; 0,15; 0,30 m e sem pastejo) e de dois mecanismos sulcadores (haste e disco), utilizados na semeadura pos-pastejo. Apos a semeadura, foram avaliados a profundidade de deposicao das sementes, o indice de velocidade de emergencia de plântulas, o estande final de plantas, a altura inicial e de insercao de espigas e o rendimento de graos. As diferentes intensidades de pastagem influenciaram significativamente a profundidade de deposicao de sementes, a altura inicial de plantas e de insercao da primeira espiga e a produtividade, sendo que a altura de pasto remanescente de 0,05 m apresentou os menores valores de profundidade de deposicao de sementes, quando comparada com os demais niveis. Os diferentes mecanismos sulcadores influenciaram apenas a profundidade de deposicao de sementes.

Efeito de cargas aplicadas e profundidades de semeadura no desenvolvimento da cultura do feijão em sistema plantio direto

Dentre os fatores primordiais para a germinacao estao a umidade, a temperatura e a aeracao do solo. E importante citar que esses fatores sao diretamente influenciados pelo estado de compactacao do solo ao redor da semente. Objetivou-se, neste trabalho, estudar os efeitos da combinacao entre profundidades de semeadura e cargas aplicadas pela roda compactadora da semeadora-adubadora sobre o desenvolvimento da cultura do feijao, em sistema plantio direto. Foi utilizado o esquema fatorial no delineamento em blocos ao acaso, composto por doze tratamentos (tres profundidades de semeadura e quatro niveis de cargas aplicadas pela roda compactadora) e quatro repeticoes. Os resultados mostraram que a profundidade de semeadura influenciou, significativamente, o indice de velocidade de emergencia, os estandes inicial e final de plantas e o rendimento da cultura. As diferentes cargas aplicadas pela roda compactadora nao influenciaram significativamente as variaveis avaliadas.

Manejos de cobertura, mecanismos sulcadores e velocidades de operação sobre a semeadura direta da cultura do milho

Abstract The stubble covering left over represents the biggest difference of the direct seeding cultivation, providing improvement on biological, chemical and physical soil conditions. Nevertheless, the dry matter remaining may difficult the seeding process, demanding additional management of covering. The aim of this study was to evaluate the development and yield of corn cultivation submitted to different methods of stubble management, furrowing machinery and working speed. A block outlining was used at random with sub-divided lots consisting of 16 treatments and four repetitions, totalizing 64 experimental unities. The treatments consisted of a combination between four stubble managements (harrowed, rolled, grinded and desiccated stubble), two furrowing machines (double disc and furrowing shank) and two seeding velocities (4.5 e 7.0 km h -1 ). Deposition depth was evaluated, as well as mobilized soil area, eeding distribution, initial plant stand, rows per corn spike, grain per row, weight of thousand grains and crop yield. The data were submitted to the analysis of variance and since there were sig-nificant differences, the averages were compared by the Tukey test, at 5% of significance. The working speed of 7.0 km h

DISTRIBUIÇÃO E PROBABILIDADE DE OCORRÊNCIA DE PRECIPITAÇÃO EM CÁCERES (MT)

Rainfall is an important meteorological element, and the knowledge on its historical records is relevant for monitoring the impacts caused by its prolonged excess or lack. This study aimed to evaluate the monthly and annual rainfall variability and the probability for its occurrence, by using the incomplete Gamma distribution model, for the rainfall data from Caceres, Mato Grosso State, Brazil. A series of 26 years data, provided by the National Institute of Meteorology, which supports a station in Caceres, was used. The annual rainfall amounts showed great variability, with minimum of 972.9 mm, in 1985, and maximum of 1,624.1 mm, in 1998. The monthly data pointed out two well defined seasons: the dry season (May to September) and the rainy one (October to April). The lowest monthly averages occurred in June, July, and August, with 16.59 mm, 17.90 mm, and 20.09 mm, respectively. The estimates for the ? parameter ranged from 0.9, in June and August, to 13.4, in March. The ? parameter ranged from 13.2, in March, to 33.1, in January. The highest rainfall probability takes place from December to March, while June, July, and August show the lowest rainfall probability.

Semeadura de milho com dois mecanismos sulcadores sob diferentes intensidades de pastejo

Crop-livestock integration can be defined as a system that integrates both activities in order to maximize rational land use and minimize production costs. The work aimed to evaluate the sowing of maize with two furrowers mechanisms in a grazing area under different managements on integrated crop-livestock system. The experiment was carried out in a randomized block design with four replicates. The treatments consisted by four combination of grazing intensities (0.25-0.05; 0.30-0.10; 0.35-0.15 m and ungrazed, respectively to the pasture height at the entry and exit of animals from the paddocks) and two furrowers mechanisms (shoe and double disc). Bulk density and soil macroporosity were evaluated post graze, as well as sowing depth, area of mobilized soil, plant stand and corn yield. Areas with highest grazing intensity provided a significant increase in bulk density. The area of mobilized soil was 0.0071 and 0.0103 m2 for the double disc and rod, respectively, having the rod presented greater sowing depth. For the furrower mechanism of double disc type, the yield decreased linearly with the increase of grazing intensity, and the same was mitigated when the rod was used.