Advertisement

Energy Analysis of Organic and Conventional Agricultural Systems

  • Göte Bertilsson
  • Holger Kirchmann
  • Lars Bergström

Abstract

Energy parameters of a Swedish long-term field experiment comparing organic and conventional agricultural systems were evaluated. There is great potential for misinterpretation of system comparisons as a result of choice of data and how energy data are expressed. For example, reported yields based on single crops and not the whole rotation can result in significantly different interpretations. Energy use per unit yield was lower in organic crop and animal production than in the corresponding conventional system, as previously found in other studies. This is due to the exclusion of N fertiliser, the largest energy input in conventional cropping systems. Energy use per unit yield expresses system efficiency, but the term is insufficient to evaluate the energy characteristics of agricultural systems. Calculation of the most important energy component, net energy production per unit area, showed that conventional systems produced far more energy per hectare than organic systems. The energy productivity (output/input ratio), i.e. the energy return on inputs, was at least six in both types of agriculture, revealing the highly positive energy balance of crop production in general. Lower yields in the organic systems, and consequently lower energy production per unit area, mean that more land is required to produce the same amount of energy. This greater land requirement in organic production must be considered in energy balances. When the same area of land is available for organic and conventional crop production, the latter allows for complementary bio-energy production and can produce all the energy required for farming, such as fuels, N fertilisers, etc., in the form of ethanol. In a complete energy balance, options such as combustion, gasification or use as fodder of protein residues from ethanol production must also be taken into account. There is a common belief that the high fossil fuel requirement in N fertiliser production is non-sustainable. This is a misconception, since the use of N fertilisers provides a net energy gain. If N fertilisers were to be completely replaced by biological N2 fixation, net energy production would be significantly lower. In addition, N fertiliser production can be based on renewable energy sources such as bio-fuels produced by gasification. Conventional crop production is thus energetically fully sustainable. Energy analyses of agricultural systems presented in this chapter illustrate that published data may require recalculation in relation to the background, prevailing trends and boundary conditions, and subsequent re-interpretation. New perspectives on energy use must also be considered.

Keywords

Bio-fuel production Cropping systems Energy budgets Energy parameters Energy use 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Andrén, O., Kätterer, T., and Kirchmann, H., 2008, How will conversion to organic cereal production affect carbon stocks in Swedish agricultural soils? in: Organic Crop Production – Ambitions and Limitations, H. Kirchmann and L. Bergström, eds., Springer, Dordrecht, The Netherlands.Google Scholar
  2. Balwinder, P.S., and Fluck, R.C., 1993, Energy productivity of a production system: Analysis and measurement, Agric. Syst. 43: 415–437.CrossRefGoogle Scholar
  3. Baumann, H., and Tillman, A.-M., 2004, The Hitch-Hiker’s Guide to LCA, Studentlitteratur, Lund, Sweden, 543p.Google Scholar
  4. Bergström, L., Bowman, B.T., and Sims, J.T., 2005, Definition of sustainable and unsustainable issues in nutrient management of modern agriculture, Soil Use Manage. 21: 76–81.Google Scholar
  5. Bertilsson, G., 1993, Environmental consequences of different farming systems using good agricultural practices, International Fertiliser Society, Proceedings No. 332, York, UK.Google Scholar
  6. Brentrup, F., Küsters, J., Lammel, J., and Kuhlmann, H., 2004a, Environmental impact assessment of agricultural production systems using the Life Cycle Assessment (LCA) methodology. I. Theoretical concept of a LCA method tailored to crop production, Eur. J. Agron. 20: 247–264.CrossRefGoogle Scholar
  7. Brentrup, F., Küsters, J., Lammel, J., Barraclough, P., and Kuhlmann, H., 2004b, Environmental impact assessment of agricultural production systems using the Life Cycle Assessment (LCA) methodology. II. The application to N fertiliser use in winter wheat production systems, Eur. J. Agron. 20: 265–279.CrossRefGoogle Scholar
  8. Bonny, S., 1993, Is agriculture using more and more energy? A French case study, Agric. Syst. 43: 51–66.CrossRefGoogle Scholar
  9. Carlgren, K., and Mattsson, L., 2001, Swedish soil fertility experiments, Acta Agric. Scand. (Section B) 51: 29–78.Google Scholar
  10. Casey, J.W., and Holden, N.M., 2006, Greenhouse gas emissions from conventional agri-environmental scheme and organic Irish suckler-beef units, J. Environ. Qual. 35: 231–239.PubMedCrossRefGoogle Scholar
  11. Cederberg, C., and Mattsson, B., 2000, Life cycle assessment of milk production – a comparison of conventional and organic farming, J. Clean. Prod. 8: 49–60.CrossRefGoogle Scholar
  12. Cleveland, C.J., 1995, The direct and indirect use of fossil fuels and electricity in USA agriculture, 1910–1990, Agric. Ecosyst. Environ. 55: 111–121.CrossRefGoogle Scholar
  13. Connor, D., and Mingues, I., 2006, Looking at biofuels and bioenergy (Letters), Science 312: 1743.PubMedGoogle Scholar
  14. Corré, W., Schröder, J., and Verhagen, J., 2003, Energy use in conventional and organic farming systems, Proceedings No. 511, International Fertiliser Society, York, UK.Google Scholar
  15. Dalgaard, T., Halberg, N., and Porter, J., 2001, A model for fossil energy use in Danish agriculture used to compare organic and conventional farming, Agric. Ecosyst. Environ. 87: 51–65.CrossRefGoogle Scholar
  16. Eckert, H., Breitschuh, G., and Sauerbeck, D., 1999, Kriterien umweltverträglicher Landbewirtschaftung (KUL) – ein Verfahren zur ökologischen Bewertung von Landwirtschaftsbetrieben, Agribiol. Res. 52: 57–76 (In German).Google Scholar
  17. Finkbeiner, M., Inaba, A., Tan, R.B.H., Christiansen, K., and Klüppel, H.-G., 2006, The new international standards for life cycle assessment: ISO 14040 and ISO 14044, Int. J. LCA 11: 80–85.Google Scholar
  18. Fluck, R.C., 1992, Energy in World Agriculture, Elsevier, Amsterdam, The Netherlands, 367p.Google Scholar
  19. Hirst, E., 1974, Food-related energy requirements, Science 184: 134–138.PubMedCrossRefGoogle Scholar
  20. Horne, R.E., Mortimer, N.D., and Elsayed, M.A., 2003, Energy and carbon balances of biofuels production: Biodiesel and bioethanol, Proceedings No. 510. International Fertiliser Society, York, UK.Google Scholar
  21. Hülsbergen, K.-J., and Kalk, W.-D., 2001, Energy balances in different agricultural systems – can they be improved? Proceedings No. 476, International Fertiliser Society, York, UK.Google Scholar
  22. IFA, 2006, International Fertiliser Association, Statistics, www.fertiliser.org/ifa/statistics/indicators/ind_reserves.asp, Paris. Assessed July 2006.Google Scholar
  23. ISO (International Organization for Standardization), 1997, Environmental management – life cycle assessment – Principles and framework, International Standard ISO 14040, ISO, Geneva, Switzerland.Google Scholar
  24. Ivarson, J., and Gunnarsson, A., 2001, Försök med konventionella och ekologiska odlingsformer 1987–1998, Meddelande från Södra Jordbruksförsöksdistriktet. Nr.53, Swedish University of Agricultural Sciences, Uppsala, Swden, SJFD-M-53-SE, 165p (In Swedish).Google Scholar
  25. Jenssen, T.K., and Kongshaug, G., 2003, Energy consumption and greenhouse gas emissions in fertiliser production, Proceedings No. 509, International Fertiliser Society, York, UK.Google Scholar
  26. Jenssen, T.K., 2004, N2O emissions trading – implications for the European fertiliser industry, Proceedings No. 538, International Fertiliser Society, York, UK.Google Scholar
  27. Jørgensen, U., Dalgaard, T., and Kristensen, E.S., 2005, Biomass energy in organic farming – the potential role of short rotation coppice, Biomass Bioenergy 28: 237–248.Google Scholar
  28. Kirchmann, H., Bergström, L., Kätterer, T., Andrén, O., and Andersson, R., 2008, Can organic crop production feed the world? in: Organic Crop Production – Ambitions and Limitations, H. Kirchmann and L. Bergström, eds., Springer, Dordrecht, The Netherlands.Google Scholar
  29. Lefroy, E., and Rydberg, T., 2003, Emergy evaluation of three cropping systems in southwestern Australia, Ecol. Model. 161: 195–211.CrossRefGoogle Scholar
  30. Mäder, P., Fliesbach, A., Dubois, D., Gunst, L., Fried, P., and Niggli, U., 2002, Soil fertility and biodiversity in organic farming, Science 296: 1694–1697.PubMedCrossRefGoogle Scholar
  31. Martin, J.F, Diemont, S.A.W., Powell, E., Stanton, M., and Levy-Tacher, S., 2006, Emergy evaluation of the performance and sustainability of three agricultural systems with different scales and management, Agric. Ecosyst. Environ. 115: 128–140.CrossRefGoogle Scholar
  32. Odum, H.T., 1996, Environmental Accounting: Emergy and Environmental Decision Making, John Wiley and Sons, New York, USA, 370p.Google Scholar
  33. Pimentel, D., Hurd, L.E., Belloti, A.C., Forster, M.J., Oka, I.N., Sholes, O.O., and Whitman, R.J., 1973, Food production and the energy crisis, Science 182: 443–449.PubMedCrossRefGoogle Scholar
  34. Pimentel, D., 2006, Impacts of organic farming on the efficiency of energy use in agriculture, An organic center state of science review. www.organic-center.org/reportfiles/energy ssr.pdf. Assessed October 2006.Google Scholar
  35. Ramirez, C.A., 2006, Monitoring energy efficiency in the food industry. SenterNovem, www.now.nl. Accessed June 2006.Google Scholar
  36. Ratke, G.-W., Körschens, M., and Diepenbrock, W., 2002, Substance and energy balances in the “static fertilization experiment Bad Lauchstädt”, Archiv für Acker- und Pflanzenbau und Bodenkunde 48: 423–433.Google Scholar
  37. Refsgaard, K., Halberg, N., and Kristensen, E.S., 1998, Energy utilization in crop and dairy production in organic and conventional livestock production systems, Agric. Syst. 57: 599–630.CrossRefGoogle Scholar
  38. Rydberg, T., and Jansén, J., 2002, Comparison of horse and tractor using emergy analysis, Ecol. Model. 19: 13–28.Google Scholar
  39. Törner, L., 1999, Energibalans i ekologisk och anpassad-intgrerad växtodling, Internal Report, Odling i Balans, Sweden (In Swedish).Google Scholar
  40. Uhlin, H.-E., 1998, Why energy productivity is increasing: an I-O analysis of Swedish agriculture, Agric. Ecosyst. Environ. 56: 443–465.Google Scholar
  41. Uhlin, H.-E., 1999, Energy productivity of technological agriculture-lessons from the transition of Swedish agriculture, Agric. Ecosyst. Environ. 73: 63–81.CrossRefGoogle Scholar
  42. Van den Broek, R., Treffers, D-J., Meeusen, M., van Wijk, A., Nieuwlaar, E., and Turkenburg, W., 2001, Green energy or organic food. A life cycle analysis comparing two uses of set aside land, J. Indust. Ecol. 5: 65–87.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Göte Bertilsson
    • 1
  • Holger Kirchmann
  • Lars Bergström
  1. 1.Greengard ABSE-24495 DösjebroSweden

Personalised recommendations