Desempenho energético de uma produção de eucalipto

Maximizing yields is opposed to the goal of minimizing the use of inputs. In the context of system rationalization, the addition of non-economic parameters in the decision making and the magnitude of eucalyptus plantation in Sao Paulo State, Brazil led to this study. The objective was to establish the flows and to evaluate the performance of energy transformations on eucalyptus production. The evaluated system presented three alternatives of soil acidity management: lime, ash and sludge application. The applied indicators were energy return on investment, energy intensity and energy balance, which meant, respectively, the return over energy investment, the energy content of biomass and the energy obtained per area. For the basic scenario, lime, EROI was 58.5 MJ MJ-1, energy intensity was 124.7 MJ m-3, and the energy balance was 2120.7 GJ ha-1. The required energy was larger when ash (5.2%) and sludge (57.2%) were used. The main inputs were, in order, fuel, fertilizers, herbicide and lime. Harvesting was the main operation (56.7%), followed by subsoiling. Fuel in harvesting, fertilizers and lime summed 79.6% of the total energy. The sensitivity of the system showed that the material used to control soil acidity had more effect on the energy demand (up to +57.4%) than the suggested scenarios (-5.3% when the field efficiency was increased).O contexto da racionalização dos sistemas de produção, a inserção de parâmetros não-econômicos na tomada de decisão e a magnitude do cultivo de eucalipto, no Estado de São Paulo, Brasil, nortearam este estudo, cujo objetivo foi estabelecer os fluxos e o desempenho das transformações energéticas de um sistema de produção de eucalipto. O sistema avaliado apresentou três alternativas de manejo de acidez do solo: calcário, cinzas e biossólido. Os indicadores utilizados foram o retorno de energia sobre energia investida, intensidade e balanço energéticos, que representam, respectivamente, a taxa de retorno de energia obtida, a energia contida na biomassa e a energia obtida por área. Para o cenário básico, calcário, o retorno de energia sobre energia investida foi de 58,5 MJ MJ-1, a intensidade energética da biomassa 124,7 MJ m-3 e o balanço de energia foi 2120,7 GJ ha-1. A energia demandada foi maior com cinzas (5,2%) e biossólido (57,2%). Os principais insumos foram, em ordem decrescente: combustível, fertilizantes, herbicida e calcário. A colheita é a principal operação (56,7%), seguida da subsolagem. O combustível gasto na colheita mais fertilizantes e calcário correspondem a 79,6% da energia necessária. A sensibilidade do sistema mostrou que o material de controle de acidez do solo causa maiores efeitos na demanda de energia (até +57,4%) que os cenários sugeridos (-5,3% com acréscimo da eficiência de campo).Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Conceptual Framework to Integrate Economic Drivers of Decision Making for Technology Adoption in Agriculture

This study evaluates how much technology adoption could cost in a variety of crop-production scenarios. Cost-reduction simulations consider scenarios of higher input use efficiency such as reducing the usage of diesel, labor, irrigation, fertilizer, herbicide, and seed, among others. The scenarios aim to increase yields by integrating the effect of each input-reduction on the total operating costs. Agricultural production estimates for Nebraska in the US indicates that a technology that saves 1% of diesel is cost-effective, costing between USD 0.15/ha and USD 0.32/ha (for corn). Improvements on input use efficiency should be prioritized to incentivize technology development and adoption. This study balances input costs and crop production, allowing the identification of adoption cost thresholds tailored to specific farming scenarios. It also enabled interpretations regarding optimal scenarios for technology adoption. In addition, this study indicates that irrigated systems foster the adoption of technologies more than in dryland cropping systems

Water, Energy, and Carbon Footprints of Bioethanol from the U.S. and Brazil

Driven by biofuel policies, which aim to reduce greenhouse gas (GHG) emissions and increase domestic energy supply, global production and consumption of bioethanol have doubled between 2007 and 2016, with rapid growth in corn-based bioethanol in the U.S. and sugar cane-based bioethanol in Brazil. Advances in crop yields, energy use efficiency in fertilizer production, biomass-to-ethanol conversion rates, and energy efficiency in ethanol production have improved the energy balance and GHG emission reduction potential of bioethanol. In the current study, the water, energy, and carbon footprints of bioethanol from corn in the U.S. and sugar cane in Brazil were assessed. The results show that U.S. corn bioethanol has a smaller water footprint (541 L water/L bioethanol) than Brazilian sugar cane bioethanol (1115 L water/L bioethanol). Brazilian sugar cane bioethanol has, however, a better energy balance (17.7 MJ/L bioethanol) and smaller carbon footprint (38.5 g CO2e/MJ) than U.S. bioethanol, which has an energy balance of 11.2 MJ/L bioethanol and carbon footprint of 44.9 g CO2e/MJ. The results show regional differences in the three footprints and highlight the need to take these differences into consideration to understand the implications of biofuel production for local water resources, net energy production, and climate change mitigation

2019 Nebraska Water Productivity Report

Nebraska’s agricultural production is diverse and vast, ranking the state fourth in total value of agricultural products in the U.S. The state is a national leader in terms of agricultural production: it is the third largest producer of corn and second largest in cattle production. Nebraska is also the second largest producer of ethanol and distillers’ grains. The production and use of these three commodities are highly interlinked. Corn is a major input in livestock feed and the ethanol industry. Ethanol plants then produce distillers’ grains as a co-product that is also used as livestock feed, thus forming what the Nebraska Corn Board refers to as “Nebraska’s Golden Triangle.” The main objective of the current report is to assess the water productivity of crops and livestock products, and the water, energy and carbon footprint of ethanol produced from corn. The findings show that: • The observed shift to more efficient irrigation systems (eg. changing from gravity to center pivot systems) and setting regulatory limits on pumping for irrigation has helped to reduce the field level irrigation application depth in three Natural Resources Districts (NRDs): Central Platte, Lower Niobrara, and Tri-Basin. The irrigation application rate in the three NRDs studied has dropped on average 20% for cornfields and 8% for soybean fields between 2004 and 2013. • The yield and modeled water productivity (WP) of both irrigated and rainfed corn decreases from eastern to western Nebraska. The drop in irrigated corn yield in western Nebraska is due to a shorter growth season in the west compared to eastern part of the state due to altitude • The modeled water productivity of the two major crops, corn and soybeans, has increased over the years. Between 1990 and 2014, the average WP of corn and soybeans has increased 1.7 and 1.8 times, respectively. These increases closely follow the increase in the crop yields in Nebraska. • There are WP gaps for corn and soybeans that, if targeted investments and improvements are feasible, will help reduce pressure on water resources. • Livestock production (swine and cattle, and eggs) has increased considerably between 1960 and 2016. The increase in livestock production has been accompanied by an increase in animal feed demand. The rate of feed demand has risen more slowly than the rate of increased production, due to increases in livestock productivity. • From 1960 to 2016, the WP of livestock products (beef, pork, chicken meat, turkey meat, milk, and eggs) increased considerably, from 1.8 times for beef to 5.1 times for milk. • Setting benchmarks, estimating the WP gaps, and identifying the critical factors affecting WP are potential future areas of research and investment to enhance the WP of livestock products. • Bioethanol from Nebraska’s corn produces roughly two times more energy output for every unit of fossil fuel input and reduces greenhouse gas (GHG) emission by 53% relative to gasoline

Conceptual Framework to Integrate Economic Drivers of Decision Making for Technology Adoption in Agriculture

This study evaluates how much technology adoption could cost in a variety of crop-production scenarios. Cost-reduction simulations consider scenarios of higher input use efficiency such as reducing the usage of diesel, labor, irrigation, fertilizer, herbicide, and seed, among others. The scenarios aim to increase yields by integrating the effect of each input-reduction on the total operating costs. Agricultural production estimates for Nebraska in the US indicates that a technology that saves 1% of diesel is cost-effective, costing between USD 0.15/ha and USD 0.32/ha (for corn). Improvements on input use efficiency should be prioritized to incentivize technology development and adoption. This study balances input costs and crop production, allowing the identification of adoption cost thresholds tailored to specific farming scenarios. It also enabled interpretations regarding optimal scenarios for technology adoption. In addition, this study indicates that irrigated systems foster the adoption of technologies more than in dryland cropping systems

Energy-Based Evaluations on Eucalyptus Biomass Production

Dependence on finite resources brings economic, social, and environmental concerns. Planted forests are a biomass alternative to the exploitation of natural forests. In the exploitation of the planted forests, planning and management are key to achieve success, so in forestry operations, both economic and noneconomic factors must be considered. This study aimed to compare eucalyptus biomass production through energy embodiment of anthropogenic inputs and resource embodiment including environmental contribution (emergy) for the commercial forest in the Sao Paulo, Brazil. Energy analyses and emergy synthesis were accomplished for the eucalyptus production cycles. It was determined that emergy synthesis of eucalyptus production and sensibility analysis for three scenarios to adjust soil acidity (lime, ash, and sludge). For both, energy analysis and emergy synthesis, harvesting presented the highest input demand. Results show the differences between energy analysis and emergy synthesis are in the conceptual underpinnings and accounting procedures. Both evaluations present similar trends and differ in the magnitude of the participation of an input due to its origin. For instance, inputs extracted from ores, which represent environmental contribution, are more relevant for emergy synthesis. On the other hand, inputs from industrial processes are more important for energy analysis