Thiago Libório Romanelli

Material flow determination through agricultural machinery management

The approach of material embodiment in agricultural production systems is important because it determines the convergence of inputs (indirectly, the natural resources) to the field. Additionally, material flow is the basis for both environmental (energy analysis, emergy synthesis, life-cycle analysis and carbon inventories) and economical analyses. Since different materials cannot compose a single index, generally these flows are not shown, making comparisons among approaches difficult. Another aspect that makes comparisons difficult is the definition of the boundary of the studied system. If these boundaries differ, results will also be different, hiding actual distinctions among systems. The present study aims to suggest an arrangement of existing models to determine material flow in agricultural production systems. The following steps were considered: i) the adoption of a diagram language to represent the analyzed system; ii) determination of the material flow for directly applied inputs; iii) determination of the material flow for indirectly applied inputs, which included: determination of the effective field capacity; fuel consumption; machinery depreciation; and labor. Data on fuel consumption were compared with the models presented. The best model applied was a fixed parameter based on engine power (0.163 L kW-1 h-1). The determination of the material flow for maize silage production presented similar results as those obtained in regional databases.

Energy balance methodology and modeling of supplementary forage production for cattle in Brazil

A pecuaria e a principal fonte de proteina no Brasil, e sofre pela estacionalidade das chuvas, necessitando-se da suplementacao alimentar. Para amenizar tais problemas surgem tecnicas visando o aumento da produtividade, porem demandando mais energia. O balanco energetico e uma importante ferramenta para avaliar a eficiencia com que um sistema de producao utiliza os insumos, pois relaciona os fluxos de energia de entrada (input) e a energia disponibilizada pelo sistema (output). No entanto, nao ha uma metodologia padrao para tal analise, e ainda analisar diferentes opcoes nao e uma tarefa facil, pela complexidade de sistemas agricolas e pelas interacoes de suas variaveis. Sendo assim, o presente trabalho objetivou propor uma metodologia de determinacao do balanco energetico, que desse suporte ao desenvolvimento de um modelo em planilha eletronica. Este foi utilizado para avaliar dois sistemas: um de producao de silagem de milho (Zea mays L.) e um de silagem emurchecida de Tifton 85 (Cynodon spp.). A silagem de milho apresentou balancos energeticos bruto de 14,08 e a emurchecida 0,98, ja para o balanco de energia digestivel foram 9,12 e 0,99, respectivamente. As adubacoes demandaram 73,4% do total de energia na silagem de milho e a irrigacao 99,7% na emurchecida. A analise de sensibilidade indicou produtividade e teor de materia seca como variaveis criticas do balanco energetico para a silagem de milho. Na emurchecida tal analise nao indicou variavel alguma. Reducoes da concentracao do fertilizante e uso de irrigacao foram as melhores alternativas para o milho e o Tifton 85, respectivamente.

Capacity of the mechanical harvesting process of sugar cane billets

The mechanized harvest of sugar cane (Saccharum officinarum L.) in Brazil is an irreversible trend and it comes with a great concern about the quality of the cane delivered to the industry. A key component to quality is the billet length which affects the processing of raw material, cane deterioration, invisible losses and load density of transport vehicles. Thus, due to the importance of the billet standard in quality and cost of raw material, this study aimed to evaluate if the mechanized harvesting of sugar cane can supply the quality requirements for the crushing process, regarding the billet length. A plot with burnt sugar cane (3.2 ha) and another one with green sugar cane (8.0 ha) were selected to be harvested by two (2) self-propelled sugar cane harvesters. For each harvested 0.4 ha a sample from each infield wagon was collected. The sample was composed by ten billets. The variability in burnt sugar cane was higher than in green sugar cane, and both harvesters did not present the capacity of keeping the billets with similar lengths when operating either in burnt or green conditions.

Energy performance of a production system of eucalyptus

O contexto da racionalizacao dos sistemas de producao, a insercao de parâmetros nao-economicos na tomada de decisao e a magnitude do cultivo de eucalipto, no Estado de Sao Paulo, Brasil, nortearam este estudo, cujo objetivo foi estabelecer os fluxos e o desempenho das transformacoes energeticas de um sistema de producao de eucalipto. O sistema avaliado apresentou tres alternativas de manejo de acidez do solo: calcario, cinzas e biossolido. Os indicadores utilizados foram o retorno de energia sobre energia investida, intensidade e balanco energeticos, que representam, respectivamente, a taxa de retorno de energia obtida, a energia contida na biomassa e a energia obtida por area. Para o cenario basico, calcario, o retorno de energia sobre energia investida foi de 58,5 MJ MJ-1, a intensidade energetica da biomassa 124,7 MJ m-3 e o balanco de energia foi 2120,7 GJ ha-1. A energia demandada foi maior com cinzas (5,2%) e biossolido (57,2%). Os principais insumos foram, em ordem decrescente: combustivel, fertilizantes, herbicida e calcario. A colheita e a principal operacao (56,7%), seguida da subsolagem. O combustivel gasto na colheita mais fertilizantes e calcario correspondem a 79,6% da energia necessaria. A sensibilidade do sistema mostrou que o material de controle de acidez do solo causa maiores efeitos na demanda de energia (ate +57,4%) que os cenarios sugeridos (-5,3% com acrescimo da eficiencia de campo).

Material embodiment and energy flows as efficiency indicators of soybean (Glycine max) production in Brazil

As the requirement for agriculture to be environmentally suitable there is a necessity to adopt indicators and methodologies approaching sustainability. In Brazil, biodiesel addition into diesel is mandatory and soybean oil is its main source. The material embodiment determines the convergence of inputs into the crop. Moreover, the material flows are necessary for any environmental analysis. This study evaluated distinct production scenarios, and also conventional versus GMO crops, through the material embodiment and energy analysis. GMO crops demanded less indirectly applied inputs. The energy balance showed linearity with yield, whereas for EROI, the increases in input and yield were not affected.

Energy flow in castor bean (Ricinus communis L.) production systems

A analise energetica e uma forma de se avaliar a sustentabilidade de um sistema produtivo, apesar de ainda pouco utilizada no setor agropecuario. Inserida neste setor encontra-se a producao da mamoneira (Ricinus communis L.), cultura ainda pouco estudada e que apresenta grande importância para o agronegocio brasileiro. Avaliou-se sob a otica energetica a producao potencial de oleo de mamona em dois sistemas de cultivo: com baixa (Sistema 1) e media (Sistema 2) tecnologias. Foi realizada a quantificacao dos fluxos de materiais empregados nos dois sistemas de producao e conversao destes fatores em unidades de energia. Os fluxos de energia de entrada foram de 3.170,6 MJ ha1 e 10.366 MJ ha1 para os sistemas 1 e 2, respectivamente. O balanco de energia foi de 11.938,2 MJ ha1 no sistema 1 e 16.296,5 MJ ha1 no sistema 2. A lucratividade energetica, retorno em energia sobre energia investida (EROI) do sistema 1 foi de 3,8 e no sistema 2 de 2,6. Apesar de apresentar uma maior demanda energetica e menor EROI, o sistema 2 obteve maior balanco energetico, demonstrando a maior viabilidade deste tipo de cultivo para a cultura da mamoneira.

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.

Energy embodiment in Brazilian agriculture: an overview of 23 crops.

The amount of energy required to produce a commodity or to supply a service varies from one production system to another and consequently giving rise to differing levels of environmental efficiency. Moreover, since energy prices have been continuously increasing over time, this energy amount may be a factor that has economic worth. Biomass production has a variety of end-products such as food, energy, and fiber; thus, taking into account the similarity in end-product of different crops (e.g.: sunflower, peanuts, or soybean for oil) it is possible to evaluate which crops require less energy per functional unit, such as starch, oil, and protein. This information can be used in decision-making about policies for food safety or bioenergy. In this study, 23 crops were evaluated allowing for a comparison in terms of energy embodied per functional unit. Crops were grouped as follows: starch, oil, horticultural, perennial and fiber, to provide for a deeper analysis of alternatives for the groups, and subsidize further studies comparing conventional and alternative production systems such as organic or genetically modified organisms, in terms of energy. The best energy balance observed was whole sugarcane (juice, bagasse and straw) with a surplus of 268 GJ ha−1 yr−1; palm shows the highest energy return on investment with a ratio of approximately 30:1. For carbohydrates and protein production, cassava and soybean, respectively, emerged as the crops offering the greatest energy savings in the production of these functional foods.

Energy demand in citrus production under varied operational efficiency values

Citrus orchards are very important in Brazil, especially in Sao Paulo State, where occupy an area of 600,000 ha approximately. To identify sustainability degree of citrus production system, an energy analysis allows evaluating efficiency of direct and indirect applied inputs. Thus, this study aimed to evaluate citrus production system under energetic point of view, in which invested energy is paid back with citrus production; being compared within three scenarios for operational field efficiency. As result, by sensitivity analysis was determined that fuel was the main energy demander, followed by pesticides and fertilizers. In operational work capacity analysis, all combinations between efficiency (minimum, typical and maximum) and yield levels became positive in the seventh year, except for the combination minimum efficiency and 10 % less yield, positive in the eighth year. The best combination (maximum efficiency and 10 % more yield) has promoted investment payoff around the sixth and seventh year. By this study, it is possible to determine the total energy demand to produce citrus and indentify the applied inputs that need more attention by the decision-makers. Labor and seedlings can be ommited for further studies with citrus, since they were irrelevant. Management of agricultural machinery may pose an important role on decreasing environmental impact of citrus production.

A cost prediction model for machine operation in multi-field production systems

Capacity planning in agricultural field operations needs to give consideration to the operational system design which involves the selection and dimensioning of production components, such as machinery and equipment. Capacity planning models currently onstream are generally based on average norm data and not on specific farm data which may vary from year to year. In this paper a model is presented for predicting the cost of in-field and transport operations for multiple-field and multiple-crop production systems. A case study from a real production system is presented in order to demonstrate the model’s functionalities and its sensitivity to parameters known to be somewhat imprecise. It was shown that the proposed model can provide operation cost predictions for complex cropping systems where labor and machinery are shared between the various operations which can be individually formulated for each individual crop. By so doing, the model can be used as a decision support system at the strategic level of management of agricultural production systems and specifically for the mid-term design process of systems in terms of labor/machinery and crop selection conforming to the criterion of profitability.