Desempenho de sulcadores no desenvolvimento e produtividade da soja em solo submetido a diferentes níveis de compactação

On the national scene, soybean crop occupies a prominent position in cultivated area and volume production, being cultivated largely in the no tillage system. This system, due to the intense traffic of machines and implements on its surface has caused soil compaction problems, which has caused the yield loss of crops. In order to minimize this effect the seeder-drill uses the systems to opening the furrow by shank or the double disc type. The use of the shank has become commonplace for allowing the disruption of the compacted surface layer, however requires greater energy demand and may cause excessive tillage in areas where there is not observed high levels of compaction. Thus, this study aimed to evaluate the effects of furrowers mechanisms and levels of soil compacting on traction requirement by a seeder-drill and on the growing and productivity of soybean in an Oxisol texture clay, in a two growing seasons. The experimental design consisted of randomized blocks with split plots with the main plots composed of four levels of soil compaction (N0 – no tillage without additional compaction, N1, N2 and N3 – no tillage subjected to compaction through two, four and six passes with tractor, respectively) corresponding to densities of soil 1.16, 1.20, 1.22 and 1.26 g cm-3, and subplots by two furrowers mechanisms (shank and double disc) with four replicates. To evaluate the average, maximum and specific traction force requested by the seeder-drill, was used a load cell, with capacity of 50 kN and sensitivity of 2 mV V-1, coupled between the tractor and seeder-drill, whose data are stored in a datalogger system model CR800 of Campbell Scientific. In addition, were evaluated the bulk density, soil mechanical resistance to penetration, sowing depth, depth and groove width, soil area mobilized, emergence speed index, emergence operation, final plant stand, stem diameter, plant height, average number of seeds per pod, weight of 1,000 seeds, number of pods per plant and crop productivity. Data were subjected to analysis of variance, the mean of furrowers were compared by Tukey test (p≤0.05), while for the factor soil compaction, polynomial regression analysis was adopted, selected models by the criterion of greater R2 and significance (p≤0.05) of equation parameters. Regardless of the crop season, penetration resistance increase as soil compaction levels up to around 0.20 m deep, and bulk density influenced the sowing quality parameters, however, did not affect the crop yield. In the first season, there was a higher productivity with the use of the shank type. In the second crop season, the shank demanded greater energetic requirement with the increase of bulk density and opposite situation with the double disc. The locking of sowing lines allow better performance of the shank to break the compacted layer.

Agriculture, Environmental Incentive Payments, and Water Quality in the Chesapeake Bay

Nonpoint sources (NPS) pollution from agriculture is the leading source of water quality impairment in U.S. rivers and streams, and a major contributor to lakes, wetlands, estuaries and coastal waters (U.S. EPA 2016). Using data from a survey of farmers in Maryland, this dissertation examines the effects of a cost sharing policy designed to encourage adoption of conservation practices that reduce NPS pollution in the Chesapeake Bay watershed. This watershed is the site of the largest Total Maximum Daily Load (TMDL) implemented to date, making it an important setting in the U.S. for water quality policy. I study two main questions related to the reduction of NPS pollution from agriculture. First, I examine the issue of additionality of cost sharing payments by estimating the direct effect of cover crop cost sharing on the acres of cover crops, and the indirect effect of cover crop cost sharing on the acres of two other practices: conservation tillage and contour/strip cropping. A two-stage simultaneous equation approach is used to correct for voluntary self-selection into cost sharing programs and account for substitution effects among conservation practices. Quasi-random Halton sequences are employed to solve the system of equations for conservation practice acreage and to minimize the computational burden involved. By considering patterns of agronomic complementarity or substitution among conservation practices (Blum et al., 1997; USDA SARE, 2012), this analysis estimates water quality impacts of the crowding-in or crowding-out of private investment in conservation due to public incentive payments. Second, I connect the econometric behavioral results with model parameters from the EPA’s Chesapeake Bay Program to conduct a policy simulation on water quality effects. I expand the econometric model to also consider the potential loss of vegetative cover due to cropland incentive payments, or slippage (Lichtenberg and Smith-Ramirez, 2011). Econometric results are linked with the Chesapeake Bay Program watershed model to estimate the change in abatement levels and costs for nitrogen, phosphorus and sediment under various behavioral scenarios. Finally, I use inverse sampling weights to derive statewide abatement quantities and costs for each of these pollutants, comparing these with TMDL targets for agriculture in Maryland.

Moto-mecanização no perímetro irrigado no Vale do Rio São Francisco: estudo do caso do Projeto Bebedouro.

O trabalho avalia a intensidade e modo de utilizacao dos tratores no Projeto Bebedouro da CODEVASF, baseado nos dados fornecidos pela CAMPIB (Cooperativa Agricola Mista do Projeto de Irrigacao do Bebedouro Ltda.) e de um produtor (Fazenda Delta Agropecuaria Ltda.) da regiao. Foram analisados os dados de tres anos (1980, 1981 e 1982) de 15 tratores da CAMPIB e de dois anos (1980 e 1981) de um trator da Fazenda Delta. A maior utilizacao dos tratores no Projeto e feita para operacoes do preparo do solo (aracao e gradagem) variando de 70% a 80% das horas produtivas no caso da CAMPIB e 58% no caso da Fazenda Delta, tendo uso anual em ambos os casos na faixa de 1.000-1.400 horas por trator. As outras operacoes realizadas usando tratores sao transporte, trilhagem e sistematizacao da terra no caso da CAMPIB, e transporte e aplicacao do calcario e adubo, no caso da Fazenda Delta. A media anual dos dias de trabalho dos tratores da CAMPIB variam de 117 a 141, e a media dos dias de trabalho por mes e por unidade de trator varia de 9,7 a 11,8 dias. No projeto, alem de tratores, a travao animal e utilizada principa.lmente para operacoes de sulcamente e cobertura do adubo, portanto, o resto das operacoes e realizado manualmente. O custo de operacoes realizadas utilizando tratores varia de 15% a 46% do custo total da mecanizacao dependente das culturas, tendo a media geral do rendimento das varias operacoes (utilizando trator) 0,31 ha/h (aracao), 0,58 ha/h (gradagem), 0,55 ha/h (sulcamento, 11,7 sacos (60 kg)/h (...).

Balanço energético da produção de feno da forrageira "massai" para criação de equídeos

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2016.

The Amplifier - v. 15, no. 7

In this issue...Liberal Art Degree, Climbing Club, Caterpillar Tractor Company, Gary Lee Knudson, Wilhelm's Flower Shop, Marcus Daly, Baseball, Du Pont Research

Effect of Pavement-Vehicle Interaction on Highway Fuel Consumption and Emission

Vehicle fuel consumption and emission are two important effectiveness measurements of sustainable transportation development. Pavement plays an essential role in goals of fuel economy improvement and greenhouse gas (GHG) emission reduction. The main objective of this dissertation study is to experimentally investigate the effect of pavement-vehicle interaction (PVI) on vehicle fuel consumption under highway driving conditions. The goal is to provide a better understanding on the role of pavement in the green transportation initiates. Four study phases are carried out. The first phase involves a preliminary field investigation to detect the fuel consumption differences between paired flexible-rigid pavement sections with repeat measurements. The second phase continues the field investigation by a more detailed and comprehensive experimental design and independently investigates the effect of pavement type on vehicle fuel consumption. The third study phase calibrates the HDM-IV fuel consumption model with data collected in the second field phase. The purpose is to understand how pavement deflection affects vehicle fuel consumption from a mechanistic approach. The last phase applies the calibrated HDM-IV model to Florida’s interstate network and estimates the total annual fuel consumption and CO2 emissions on different scenarios. The potential annual fuel savings and emission reductions are derived based on the estimation results. Statistical results from the two field studies both show fuel savings on rigid pavement compared to flexible pavement with the test conditions specified. The savings derived from the first phase are 2.50% for the passenger car at 112km/h, and 4.04% for 18-wheel tractor-trailer at 93km/h. The savings resulted from the second phase are 2.25% and 2.22% for passenger car at 93km/h and 112km/h, and 3.57% and 3.15% for the 6-wheel medium-duty truck at 89km/h and 105km/h. All savings are statistically significant at 95% Confidence Level (C.L.). From the calibrated HDM-IV model, one unit of pavement deflection (1mm) on flexible pavement can cause an excess fuel consumption by 0.234-0.311 L/100km for the passenger car and by 1.123-1.277 L/100km for the truck. The effect is more evident at lower highway speed than at higher highway speed. From the network level estimation, approximately 40 million gallons of fuel (combined gasoline and diesel) and 0.39 million tons of CO2 emission can be saved/reduced annually if all Florida’s interstate flexible pavement are converted to rigid pavement with the same roughness levels. Moreover, each 1-mile of flexible-rigid conversion can result in a reduction of 29 thousand gallons of fuel and 258 tons of CO2 emission yearly.

Work, class and conflict: a comparative study of three Cork factories, incorporating oral testimony

This dissertation presents a comparative study of three factories in Cork Harbour area, Sunbeam Wolsey (1927-90), Irish Steel (1939-2001) and the Ford Marina Plant (1917-84). All three factories were significant industrial employers in both a domestic (Irish) and a local (Cork) context and are broadly representative of the Irish manufacturing industry that was developed under the policies of tariff protection introduced in the 1930s and gradually phased out between the late 1950s and the mid-1980s. Sunbeam Wolsey was a textile and clothing concern located on the north side of Cork City that possessed a borderline monopoly within its economic sector and was among the largest private employers of female labour in twentieth century Ireland. Irish Steel was the country’s only steel mill, located on Haulbowline island, a brief ferry-ride from the seaside town of Cobh, and was unusual in being one of the few manufacturing concerns operated as a nationalised industry under the auspices of the state. The Ford Marina plant predated the introduction of protectionism by more than a decade and began as the centre of the Ford empire’s tractor manufacturing business, before switching to the production of private motor vehicles for the Irish market in 1932. All three industries were closed or sold off when the state withdrew support, either in the form of tariff protection (Ford, Sunbeam) or direct funding (Irish Steel). While devoting much attention to the three firms, the central concern of this dissertation is not the companies themselves (though the economic history portion of the dissertation is substantial), but the workers they employed, examining the lives of these individuals both as members of the Irish working class, and, more specifically, as employees of the three factories under consideration. The project can be best described as a comparative factory study, comparing and contrasting the three workforces, focusing primarily on industrial relation and the experience of work. This dissertation utilises both documentary evidence and a significant quantity of oral testimony, breaking new ground by making the workplace the central focus of its investigation. The principal aims of the study are: 1. To document the lives of those who worked in these factories, capturing through oral testimony their subjective experiences of social class and factory life, as well as differences among narrators in terms of gender and status. In achieving this aim, the study will provide a broader social context for its detailed analysis of work and industrial relations in each firm. 2. To analyse the three workplaces and determine how and why each developed such distinct systems of industrial relations at the factory level, as well as to compare and contrast these systems. 3. To examine the nature of work in each factory and to determine how work and industrial relations in each firm developed over time, relating these changes both to internal and external factors. Additionally, the project will provide a comparative analysis of these changes.

Avaliação do efeito do corte horizontal da copa, com máquina de podar de discos, em pomares de pera “Rocha

Current pear pruning making use of pneumatic shears still is a very labour intensive operation. The Proder project “Avaliação da poda mecânica em pomares de pera” was designed to contribute to solutions that would reduce the present dependence in labour and therefore to promote a reduction in pruning costs. This paper shows the results of a trial made to evaluate the influence of mechanical topping in manual pruning complement field work and pear yield. Topping was performed using a Reynolds 6DT 3.0m cutting bar with six hydraulic-driven circular disc-saws mounted in the three point tractor linkage system. The field trial was performed in a commercial orchard with 20 years, planted in an array of 4m x 2m with tree lines oriented in North-South direction. Trees were trained as the central leader system. In this trial, in a randomised complete block design with four replications, two treatments are being compared leading to 8 plots with one line of 14 trees per plot. The treatments tests were: T1 - manual pruning performed by workers using pneumatic shears, in each year; T2 - Topping the canopy parallel to the ground, using a discs-saw pruning machine mounted in a front loader of an agricultural tractor, followed by manual pruning complement performed by workers with pneumatic shears. Tree height and width was measured, before and after pruning. Work was timed and pear yields evaluated. Mechanical topping seems to be effective in the control of tree height, which can contribute to increase 14% of work rates on manual pruning complement. No significant differences in pear yield were found between treatments.