Effects of working depth and wheel slip on fuel consumption of selected tillage implements

Rising fossil fuel prices are leading to an increasing awareness of energy efficiency in plant production.  Tillage in particular can consume large amounts of fuel.  For four tillage implements (reversible mouldboard plough, short disc harrow, universal-cultivator, subsoiler), this study quantifies the effect of different working depths on fuel consumption, wheel slip, field capacity and specific energy consumption.  A four-wheel drive tractor (92 kW) was equipped with a data-acquisition system for engine speed, vehicle speed, wheel speed and fuel consumption.  Fuel consumption was measured in the fuel system with an integrated high-precision flow-meter.  The results show that the area-specific fuel consumption increased linearly with working depth for both the mouldboard plough and the short disc harrow, but disproportionately for the subsoiler.  Wheel slip was found to increase fuel consumption and decrease field capacity performance at all depths.  The influence of the engine speed was shown in a separate experiment with a universal-cultivator.  Increasing the engine speed from 1,513 r min-1 to 2,042 r min-1 results in an increase of 80% for the fuel consumption rate (L/h) and 35% for the area-specific fuel consumption (L/ha).  Future measurement of drawbar pull will allow a more detailed analysis of the energy efficiency losses at the engine, the transmission, and at the wheel/soil interface.   Keywords: fuel consumption, wheel slip, mouldboard plough, subsoiler, universal-cultivator, short disc harro

Consequences from Land Use and Indirect/Direct Land Use Change for CO2 Emissions Related to Agricultural Commodities

Increasing demand for food, feed, and fuels adds pressure on ecosystems through land use and land use change (LULUC), with greenhouse gas emissions among the most significant environmental impacts. Large regional variation in LULUC and indirect driving forces may not be adequately addressed by a one-size-fits-all approach that assigns equal LULUC emissions per unit of area, and by a focus on direct d(LU) LUC impacts only. Hence, our method integrates effects from international agricultural commodity trade as indirect emissions (iLULUC) of the demand of food and feed. In most countries, the majority of foods and feedstuffs (70% of global calories) are produced for the domestic market and the rest is exported and contributes to a hypothetical global pool of iLULUC emissions. Total LULUC emissions are calculated for individual countries, accounting for LULUC from increased domestic agricultural production for domestic consumption and for emissions imported from the global market’s iLULUC pool. Furthermore, we estimate consumption-based emission factors for specific product groups per country. Results show that vegetable oils, oil crops, and cereals account for the majority of global LULUC emissions and iLULUC results derived with the presented method cannot be compared directly to dLULUC results; however, their orders of magnitude are similar

Environmental hot spot analysis in agricultural lifecycle assessments – three case studies

Present-day agricultural technology is facing the challenge of limiting the environmental impacts of agricultural production – such as greenhouse gas emissions and demand for additional land – while meeting growing demands for agricultural products. Using the well-established method of life-cycle assessment (LCA), potential environmental impacts of agricultural production chains can be quantified and analyzed. This study presents three case studies of how the method can pinpoint environmental hot spots at different levels of agricultural production systems. The first case study centers on the tractor as the key source of transportation and traction in modern agriculture. A common Austrian tractor model was investigated over its life-cycle, using primary data from a manufacturer and measured load profiles for field work. In all but one of the impact categories studied, potential impacts were dominated by the operation phase of the tractor’s life-cycle (mainly due to diesel fuel consumption), with 84.4-99.6% of total impacts. The production phase (raw materials and final assembly) caused between 0.4% and 12.1% of impacts, while disposal of the tractor was below 1.9% in all impact categories. The second case study shifts the focus to an entire production chain for a common biogas feedstock, maize silage. System boundaries incorporate the effect of auxiliary materials such as fertilizer and pesticides manufacturing and application. The operation of machinery in the silage production chain was found to be critical to its environmental impact. For the climate change indicator GWP100 (global warming potential, 100-year reference period), emissions from tractor operation accounted for 15 g CO2-eq per kg silage (64% of total GWP100), followed by field emissions during fertilizer (biogas digestate) application with 6 g CO2-eq per kg silage (24% of total GWP100). At a larger system scale that includes a silage-fed biogas plant with electricity generated by a biogas engine, silage cultivation operations are no longer the largest contributor; the most important contributor (49.8%) is methane slip from the exhaust of the biogas engine. In the third case study, the biogas plant model is energy system in an Alpine municipality of Western Austria is expanded to include a hypothetical system that uses mainly hay from currently unused alpine grassland in a local biogas plant. Here, the relative environmental impacts depend strongly on the fossil fuels that are assumed to be displaced by the local biogas plant; methane slip emissions from the exhaust dominate the impact of the hypothetical local biogas scenario. Taken together, the case studies demonstrate the potential and limitations of LCA as a technique to support decisions of agricultural stakeholders at a variety of scales. Choosing the proper system scale is key to a successful application of this method

Market development and consequences on end-of-life management of photovoltaic implementation in Europe

Energie-Umweltmanagemen

Reevaluation of energy use in wheat production in the United States

Energy budgets for agricultural production can be used as building blocks for life‐cycle assessments that include agricultural products, and can also serve as a first step toward identifying crop production processes that benefit most from increased efficiency. A general trend toward increased energy efficiency in U.S. agriculture has been reported. For wheat cultivation, in particular, this study updates cradle‐to‐gate process analyses produced in the seventies and eighties. Input quantities were obtained from official U.S. statistics and other sources and multiplied by calculated or recently published energy coefficients. The total energy input into the production of a kilogram of average U.S. wheat grain is estimated to range from 3.1 to 4.9 MJ/kg, with a best estimate at 3.9 MJ/kg. The dominant contribution is energy embodied in nitrogen fertilizer at 47% of the total energy input, followed by diesel fuel (25%), and smaller contributions such as energy embodied in seed grain, gasoline, electricity, and phosphorus fertilizer. This distribution is reflected in the energy carrier mix, with natural gas dominating (57%), followed by diesel fuel (30%). High variability in energy coefficients masks potential gains in total energy efficiency as compared to earlier, similar U.S. studies. Estimates from an input‐output model for several input processes agree well with process analysis results, but the model's application can be limited by aggregation issues: Total energy inputs for generic food grain production were lower than wheat fertilizer inputs alone, possibly due to aggregation of diverse products into the food grain sector

Comparative thermodynamic analysis of an improved ORC process with integrated injection of process fluid

In contrast to water-steam Rankine cycles, the ORC process uses organic working fluids. For working fluids of the dry class, a recuperator heat exchanger is frequently installed to increase the cycle efficiency. This paper analyses an improved ORC process with these features: A liquid working fluid stream is injected into the vapour flow between the high-pressure and the medium-pressure stage of the turbine. Furthermore, the recuperator is replaced by a spray condenser. The main objective is to increase efficiency with moderate changes in the process layout. A thermodynamic comparison of the improved process with a state-of-the-art ORC process is carried out by simulations and optimisations. A significant efficiency gain for the improved ORC process is obtained by a combination of the aforementioned features, mainly because of an increase of the mass flow in the economiser of the vapour generator (better heat utilization) and a corresponding mass flow in the medium stage of the turbine (additional power production). As a use case, waste heat utilization from clinker cooler at a temperature level of 275 °C was simulated. The improved process would lead to a significant increase in the overall net efficiency by up to 14%, compared to a state-of-the-art ORC process.Energie-Umweltmanagemen

Precision Grassland Farming - An overview of research and technology

Lecture Notes in Informatics (LNI), Proceedings - Series of the Gesellschaft fur Informatik (GI)Precision Farming ist im Ackerbau ein weithin geläufiger Begriff. Firmen und Forschungseinrichtungen veröffentlichen regelmäßig (informations-)technologische Neuheiten. Trotz des großen Potentials hinsichtlich Ressourceneinsparung und der Überwachung des Bestands, ist festzustellen, dass Precision Farming Applikationen im Grünland bisher kaum zur Anwendung kommen. Der Beitrag soll ein Überblick über bereits vorhandene Precision Farming Anwendungen im Grünland geben, wobei die vollständige Ernteprozesskette hinsichtlich vorhandener Präzisionstechnologie beschrieben wird. Es ist festzustellen, dass vor allem Maschinen, welche sowohl im Ackerbau, als auch im Grünland genutzt werden können, einen hohen Grad der Technisierung hinsichtlich Precision Farming aufweisen. Geräte, welche jedoch ausschließlich im Grünland genutzt werden, weisen nur geringe Tendenzen in diesem Bereich auf. Häufig wurden diese lediglich zu Forschungszwecken entwickelt und kaum in die Praxis überführt. Künftig sind Forschungen, vor allem, um Bröckelverluste zu minimieren, durchzuführen

Effects of working depth and wheel slip on fuel consumption of selected tillage implements

Rising fossil fuel prices are leading to an increasing awareness of energy efficiency in plant production. Tillage in particular can consume large amounts of fuel. For four tillage implements (reversible mouldboard plough, short disc harrow, universal-cultivator, subsoiler), this study quantifies the effect of different working depths on fuel consumption, wheel slip, field capacity and specific energy consumption. A four-wheel drive tractor (92 kW) was equipped with a data-acquisition system for engine speed, vehicle speed, wheel speed and fuel consumption. Fuel consumption was measured in the fuel system with an integrated high-precision flow-meter. The results show that the area-specific fuel consumption increased linearly with working depth for both the mouldboard plough and the short disc harrow, but disproportionately for the subsoiler. Wheel slip was found to increase fuel consumption and decrease field capacity performance at all depths. The influence of the engine speed was shown in a separate experiment with a universal-cultivator. Increasing the engine speed from 1,513 r min-1 to 2,042 r min-1 results in an increase of 80% for the fuel consumption rate (L/h) and 35% for the area-specific fuel consumption (L/ha). Future measurement of drawbar pull will allow a more detailed analysis of the energy efficiency losses at the engine, the transmission, and at the wheel/soil interface