Material flow determination through agricultural machinery management

Abstract

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. Key words: LCA, material embodiment, environmental management, mechanization Determinação de fluxo de materiais por meio do gerenciamento de máquinas agrícolasRESUMO: A abordagem da incorporação material em sistemas agrícolas é importante, pois determina a convergência de insumos (indiretamente, de recursos naturais) no campo. Além disso, os fluxos de materiais são a base para quaisquer análises ambientais (análises de energia, síntese de emergia, ciclo de vida e inventários de carbono) e econômicas. Uma vez que diferentes materiais não podem compor um único índice, geralmente esses fluxos não são mostrados. Isso dificulta comparações entre análises. Outro aspecto que contribui para isso é a definição dos limites dos sistemas estudados. Se eles diferirem os resultados serão diferentes, disfarçando as distinções reais entre eles. O presente estudo visa sugerir um arranjo de modelos existentes para a determinação dos fluxos de energia e materiais em sistemas agrícolas. Os seguintes passos foram considerados: i) a adoção de uma linguagem de diagramação para representar o sistema analisado; ii) a determinação do fluxo de materiais dos insumos diretamente aplicados; iii) a determinação do fluxo de materiais dos insumos indiretamente aplicados, que envolve a capacidade de campo operacional dos sistemas mecanizados, o consumo de combustível, a depreciação de maquinário e a mão-de-obra. Dados de consumo de combustível foram comparados com os modelos apresentados. O melhor modelo aplicado foi o fixado em função da potência do motor (0,163 L kW -1 h -1

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

“…Odum developed the Energy Language System (ROMANELLI & MILAN, 2010a), which brings the advantage of determining the boundaries of the studied system, i.e., the flows that cross the boundaries and that are quantified are previously shown to the readers. In this language, there are symbols for storage (e.g., soil in agriculture), producers (plants), consumers (animals), transactions (money versus goods/service), interaction (e.g., mechanization is an interaction of labor, machinery depreciation, fuel consumption and the input applied), heat sink which represents entropy generation (only applied when using the language to represent energy flows), constant force source (rain, wind), flow limited source (sunlight due to the refraction in the atmosphere).…”

“…For instance if there is a worker helping two tractor-implement set, its labor flow may be considered as 0.5 man in addition to the labor of the tractor driver. The determination of these material flows were done according to ROMANELLI & MILAN (2010a).…”

“…So, it can be compared to the economic and yield optimums. Material flow is the basis of cost determination, since every single input multiplied by their price determines cost and also, most of the methodologies used to environmentally assess production systems are based on material flows (ROMANELLI & MILAN, 2010a), such as energy analyses (CHAVANNE & FRANGI, 2008;PIMENTEL & PATZEK, 2005;. The evaluation of how production systems demand and supply energy is vital (ROMANELLI & MILAN, 2005).…”

Impact of Irrigation and Nitrogen Fertilization on the Energy Balance and Energy Return on Investment of Jatropha Production

“…Machinery and equipment mass depreciation were determined by equation 3 (ROMANELLI; MILAN, 2010), considering a tractor with 3,940 kg, 55 kW of gross engine power and 1,200 h of lifespan. The lifespan for the sprayer was considered 2,000 h and 1,500 h for the manual grass mower used in the weed control.…”

Energy demand in citrus production under varied operational efficiency values

“…and indirect ones (machinery, labor, fuel) within crop production system. For direct inputs, mechanized operation efficiency plays a vital role in material intensity (ROMANELLI & MILAN, 2010b). Energy analysis is also used to identify benefits that new techniques may infer into agricultural system management.…”