The material embodiment in agricultural production systems is important because it determines the convergence of\r\ninputs (indirectly, the natural resources) into the crop. Besides this, the material flows are the basis for any environmental\r\n(energy analysis, emergy evaluation, life-cycle analysis and carbon inventories) and economical analyses. Since different\r\nmaterials cannot compose a single index, generally these flows are not shown and this fact makes comparisons difficult to be\r\ndone. Another aspect that makes comparisons more difficult is the establishment of the studied system�s boundary. If they\r\ndiffer, results will be different, disguising actual distinctions among systems. This study aimed to apply a methodology in\r\norder to determine material flows in agricultural production systems. A secondary goal is to show that machinery\r\nmanagement can propitiate less material convergence into the crop. A diagram language to represent the analyzed system was\r\nadopted in order to establish the systems� limit. The determination of the material flows of indirectly applied inputs (fuel\r\nconsumption; the machinery depreciation; and labor) included the determination of the effective field capacity, since the latter\r\naggregates efficiency and is able to make data related to time to be related to area. Data of fuel consumption were compared\r\nwith the models presented (the most accurate for the surveyed system was presented by Molin and Milan, 2002). The material\r\nembodiment of a maize silage production system was determined and compared with regional data, presenting similar data.\r\nFor this system and a haylage (Tifton 85) production system the embodiment was calculated for different aspects (area, yield\r\nand qualitative aspects) in order to show the importance of establishing the limit of study and indicators. A comparison\r\napproaching the efficiency was also done, the variables considered were farm size, machinery use and labor requirement,\r\nefficiency increased more than the area increase.
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