A Multidisciplinary Approach Integrating Emergy Analysis and Process Modeling for Agricultural Systems Sustainable Management—Coffee Farm Validation (original) (raw)
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Ecological Modelling, 2015
By tracking the different flows of emergy (the total amount of solar energy that was directly or indirectly required in a production process) it is possible to account for all environmental work previously involved in generating a resource, product or service. This donor-side perspective for environmental assessment has the advantage over usual economic and energy analysis in the ability to value renewable and nonrenewable environmental resource inputs both from the economy (purchased resources) and from nature (free resources) and compute their values on a common basis. On this basis, this paper presents the use of emergy synthesis on three cropping systems of the Pampa Region (Argentina) with the aim of evaluating the long-term trends (1984-2010) in emergy use and the effect of the adoption of new technologies in the study area. The cropping systems evaluated were wheat/soybean double cropping (W/S); maize (M), and spring soybean (S). Results form the emergy synthesis showed that the cropping systems studied were not only more productive but also more efficient over time. The range of the observed values for the emergy yield ratio (EYR) were 1.77-5.59, proving that the three cropping systems are considerably supported by renewable and locally available resources. The environmental load ratio (ELR) that represents the ratio between non-renewable and renewable resource inputs ranged between 0.3 and 1.43, a significant lower range compared to other extensive cropping systems. However, when inspecting the temporal dynamics of the emergy indicators, M and W/S showed a statistically significant optimum behavior, with the most favorable values just before the use of a more intensive cropping management represented by the use of genetically modified cultivars, the no-tillage adoption and the more frequent use of fertilizers at higher doses. By the time of these adoptions, both the EYR and ELR showed a breakpoint in their temporal dynamic, exhibiting a negative slope during the last years of the time series. Although the observed ranges of the emergy indicators can place these production systems among the most efficient and with the lower environmental impact, the negative trend in the emergy indicators shown in recent years constitutes a risky scenario in terms long-term sustainability.
Emergy analysis was used to analyze three agricultural systems to compare and contrast resource use, productivity, environmental impact, and overall sustainability. Emergy analysis was appropriate for this task because of its ability to transform different types of inputs to a common form (solar energy equivalents) to allow meaningful comparisons across the three systems. The systems analyzed were conventional corn (Zea mays L.) production in Kansas, USA, blackberry (Rubus rubus Watson) production in Ohio, USA, and a Lacandon polycultural rotation system in Chiapas, Mexico. Despite these different systems and diverse inputs, emergy allowed the quantification and comparison of flows for each system on a common basis. This allowed system-level conclusions and demonstrated the utility of emergy analysis when evaluating agricultural systems. The greatest inputs of emergy across the three systems were for fertilization and irrigation of the corn system. These two inputs accounted for 95% of the purchased emergy input to the corn system. The indigenous system was most reliant on renewable resources, and therefore, had the lowest level of environmental loading. The sustainability index for the three systems ranged from 0.06 for the corn system, to 0.65 for the blackberry system, to 115.98 for the indigenous system. The respective energy and emergy yield for each system were 2.6E9 J ha À1 year À1 and 3.57E15 sej ha À1 year À1 for the indigenous system, 3.71E10 J ha À1 year À1 and 8.59E15 sej ha À1 year À1 for the blackberry system, and 1.40E11 J ha À1 year À1 and 1.30E16 sej ha À1 year À1 for the corn system. While the indigenous system has the highest level of sustainability, its energy yield was 14 times less than the blackberry system, and 53 times less than the corn system. The results confirm the need for food production systems with large yields that are more dependent on renewable energies. #
Emergy Analysis and Bookkeeping Accounting of Conventional and Organic Coffee Production in Brazil
… -Advances in Energy Studies." Energy-Ecology …, 2004
Emergy, economic and social analyses were conducted in two different farms located in the northeast of Sao Paulo State, Brazil, that used different systems of coffee production. The farming systems studied work according to two opposing agricultural models: organic and conventional. The comparison between both systems showed that the organic system is capable of improving the economic results in small properties. These improvements were possible because the organic system made a large use of the free natural resources in the agro ecosystem. The use of these natural resources enable farmers to obtain lower costs with material inputs and have better number for permanent employment per area and also promote the recovery of the environment. The emergy analysis was able to discover that organic farm uses more natural resources and this fact allowed more economic benefits.
Engenharia Agrícola, 2015
Three growing systems of Arabica coffee were evaluated under the energy perspective, in the state of Espírito Santo in Brazil. The systems are conventional cultivation (CC), cultivation with good agricultural practices (CGP) and organic farming (OF). It was made a comparison of the energy flows within these three systems to show sustainable levels of each one based on production average data of several family-farming units. Therefore, we analyzed crop yield, total energy efficiency reverse (TEER), energy efficiency of ripe coffee (EERC) and non-renewable energy efficiency (NREE). OF system had values for TEER, EERC and NREE of 3.3 4.7 and 7.9 respectively. Yet CC showed values of 1.8, 1.9 and 1.6 for TEER, EERC and NREE respectively. Furthermore, CGP presented values for TEER, EERC and NREE of 0.7, 1.3 and 1.4 respectively. The highest yield was observed in CGP, reaching an amount of 1794 kg ha-1(17,455 MJ); however, this system expends more energy than it converts. Thus, over those...
Journal of Cleaner Production
Agricultural is essential to feed the human world but it can also degrade the physical world. Therefore, we need widely-accepted metrics to assess how prospective practices influence sustainability. We hypothesized that emergy and energy analyses considered together provide a robust, comprehensive measure of sustainability, and evaluated this hypothesis using findings from two field studies in the semiarid prairie region of Canada: a systems experiment including nine different 3-yr cropping rotation systems and a stubble experiment involving five preceding crop stubbles treatments with three nitrogen (N) addition levels. The grain yield emergy transformities of rotation systems with pulses, ranging from 0.68 to 0.83 Eþ05 sej J À1 , were 32% lower (P < 0.05) than rotations without pulses. Significantly lower grain transformity of durum wheat grown on pulse stubbles than grown on durum wheat stubble were observed for both the systems and stubble experiments, suggested a higher crop production efficiency conferred by previous pulse crops. The emergy sustainability index (ESI) of Fallow-Durum wheat-Pea (F-D-P) rotation (1.94) was 1.3e2.2 times that of other rotations, while the continuous rotations increased ESI from 1.00e1.11 to ESI DQ of 2.00e2.21 by considering the storage increase (DQ) of the system, i.e. soil organic carbon (SOC). The grain yield/energy input ratio (G/I) and energy output/energy input ratio (O/I) for F-D-P rotation (775 g MJ À1 and 12.9, respectively) were significantly (P < 0.05) higher than those of all other rotations for its low energy input, which was obtained at the cost of huge SOC decrease. Modified energy use efficiency indices, G/I DSOC and O/I DSOC , were proposed in the present study to include the effect of SOC change (DSOC) in energy use efficiency by regarding DSOC as energy input where the system depleted SOC and as energy output where SOC accumulated. The G/I DSOC and O/I DSOC ratios for continuous rotations were significantly (P < 0.05) higher than those of other rotations, indicating higher energy use efficiency in continuous rotation systems. Therefore, ESI DQ and O/I DSOC are recommended as sustainability indicators in emergy and energy analysis respectively, and we recommend that emergy and energy analysis should be done and considered together to have a more informative assessment of relative sustainability and efficiency of cropping systems.
Emergy efficiency of land-use systems in the brazilian semi-arid region
Revista Ibero-Americana de Ciências Ambientais, 2020
Emergy analysis is used to evaluate agricultural management systems in order to diagnose their efficiency in using economic and natural resources. In this study, emergy analysis was used to evaluate an agroforestry production model and compare it to the traditional production model used in the semi-arid region of the northeast of Brazil. The agroforestry model comprises three subsystems: agrosilvopastoral (ASP), silvopastoral (SP) and preserved caatinga (CAT). For the traditional model, three subsystems were evaluated: an area under cultivation (AC); an area lying fallow for six years (F6); and an area fallow for nine years (F9). For each model and its respective subsystems, all input and output energy flows were identified. These flows were later quantified and transformed into emergy using their respective transformity values. The emergy performance of the systems and subsystems was evaluated by the indices: transformity (Tr), emergy investment ratio (EIR), emergy yield ratio (EYR...
Emergy evaluation for decision-making in complex multifunctional farming systems
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In a montado farm, commonly found in the South Portugal, human activities benefit from important fluxes of renewable resources. In this study, traditional economic and emergy evaluations are compared to determine their potential contributions to understanding this complex system and applied to a case study of a farm. This allows us to determine how each method values local natural resources and purchased factors of production and services in an empirical context. Results show that the montado farm has a renewable component evaluated at 27% of the total social costs of the system and that the work of natural resources is undervalued in economic budget accounting. Economic evaluation's relative value of purchased factors and services is three and half times higher than their emergy share. We propose that complementing economic budget accounting with emergy accounting provides a benchmark to evaluate the environmental contribution to agricultural and farming systems. In this way, factors external to markets can be evaluated for farming systems, bringing to economic analysis a full evaluation of resources, including the bio-geophysical system's contributions to wealth, enlarging total economic value of resources with a donor perspective enabling a better informed and comprehensive accounting to attain sustainable economic decisions and public policies.