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Agroecology: Applying Ecological Principles to Agriculture


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The presentation begins with a history of agriculture and then outlines conventional practices and the associated emergent challenges. The value of applying ecological principles to conventional agriculture is discussed with supporting evidence from various studies. The application of ecological principles is explored in the context of agricultural sustainability.

Agroecology: Applying Ecological Principles to Agriculture

  1. 1. Caroline WrobelES8912 – Applied Ecology March 7th, 2012
  2. 2. History of Agriculture Ancient Egypt
  3. 3. History of Agriculture Ploughing on a bonanza farm
  4. 4. Changes in AgricultureTable 1. One hundred years of structural change in U.S. agriculture. 1900 1930 1945 1970 2000 Number of farms 5.7 6.3 5.9 2.9 2.1 (millions) Average size of farm 146 151 195 376 441 (acres) Average number of 5.1 4.5 4.6 2.7 1.3 commodities produced per farm Farm share of 39 25 17 5 1 population (%) Rural share of 60 44 36 26 21 population (%) (Dimitri & Effland, 2005)
  5. 5. Figure 1. World food production from 1960 to 2000measured as the sum of cereals, grains, and root crops.(Tilman, 1999)
  6. 6. % of land area Figure 2. Percentage of global land area that is used for agriculture.
  7. 7. Impacts• Reduction in biodiversity • 30,000 edible plant species • 20 species in current food load • 3 species account for more than 50%• Decreased soil fertility• Eutrophication• Soil erosion• Impaired soil biota• Salinization• Loss of important species• Encroachment on surrounding ecosystems
  8. 8. Case Study: Kesterson Reservoir, San Joaquin Valley, California
  9. 9. Agroecology: The integrative study of the ecology of the entire food system, encompassing ecological, social and environmental dimensions (Francis et al., 2003) OR The application of ecological concepts and principles to the design and management of sustainable agroecosystems (Altieri, 2004)
  10. 10. Agroecology in Action BiodiversityFigure 3. A biodiversity experiment at the Cedar Creek Ecosystem ScienceReserve (a) demonstrates the relationship between the number of plantedspecies and ecosystem stability (b) or species stability (c).(Tilman et al., 2006)
  11. 11. Agroecology in Action BiodiversityFigure 4. Number of studies that show organic farming having a positive(green bar), negative (red bar) or no effect (number in white circle) onbiodiversity of various animal and plant groups in comparison to non-organic farm management. Summary of 95 scientific publications.(Hole et al., 2005)
  12. 12. Capacity of organic conversionTrait-based ecologyLevels of biodiversityAdditional food crops
  13. 13. Agroecology in Action Pest Management  Integrated Pest Management (IPM)
  14. 14. How to make it easier to followImpacts of particular biocontrolagentsDetailed impacts of pestsEcological data needed inframework
  15. 15. Agroecology in Action Soil Management
  16. 16. Agroecology in Action Soil Management  Integrated Soil Management (ISM) Soil Tillage & Conservation Management Crop Water Management Management Integrated Soil Management Land Use Nutrient Management Management
  17. 17. Agroecology in Action Soil Management  Integrated Soil Management (ISM) Techniques Minimum tillage Cover cropping Slope barriers Microbial inocula and biocontrol Maintenance of organic and inorganic nutrients Bioremediation Mulching and manuring
  18. 18. Decomposer ecologyOrganisms and ecosystemfunctionProductivity of soil biota
  19. 19. • Mosaic plots • Green manures• Fallow areas• Polycultures
  20. 20. References• Altieri, M. (2004). Linking ecologists and traditional farmers in the search for sustainable agriculture. Frontiers in Ecology and the Environment, 2(1): 35-42.• Brussaard, L., Caron, P., Campbell, B., Lipper, L., Mainka, S., Rabbinge, R., et al. (2010). Reconciling biodiversity conservation and food security: scientific challenges for a new agriculture. Current Opinion in Environmental Sustainability, 2: 34-42.• Chen, L., Lee, D., Song, Z., Suh, H., & Lu, B. (2004). Gene Flow from Cultivated Rice (Oryza sativa) to its Weedy and Wild Relatives. Annals of Botany, 93(1): 67-73.• Dale, V., & Polasky, S. (2007). Measures of the effects of agricultural practices on ecosystem services. Ecological Economics, 64(2): 286-296.• De Clerck-Floate, R., & Bourchier, R. (2000). Ecological Principles of Biological Control: From Population Theory to Wedd Biocontrol Practice. Proceedings of the X International Symposium on Biological Control of Weeds (pp. 517-520). Bozeman, MT: Montana State University.• Dover, M., & Talbot, L. (1987). To feed the earth: agroecology for sustainable development. Washington, DC: World Resources Institute.• Drinkwater, L., & Snapp, S. (2007). Nutrients in Agroecosystems: Rethinking the Management Paradigm. Advances in Agronomy, 92: 163-186.• Ehler, L. (2006). Integrated pest management (IPM): definition, historical development and implementation, and the other IPM. Pest Management Science, 62: 787-789.• Ewel, J. (1999). Natural systems as models for the design of sustainable systems of land use. Agroforestry Systems, 45: 1-21.• Fagan, W., Lewis, M., & van den Driessche, P. (2002). Invasion theory and biological control. Ecology Letters, 5: 148-157.• Fitter, A., Gilligan, C., Hollingworth, K., Kleczkowski, A., Twyman, R., Pitchford, J., et al. (2005). Biodiversity and ecosystem function in soil. Functional Ecology, 19: 369-377.• Francis, C., Lieblein, G., Gliessman, S., Breland, T., Creamer, N., Harwood, R., et al. (2003). Agroecology: The Ecology of Food Systems. Journal of Sustainable Agriculture, 22(3): 99-118.• Gilpin, M., Gall, G., & Woodruff, D. (1992). Ecological Dynamics and Agricultural Landscapes. Agriculture, Ecosystems and Environment, 42: 27-52.• Hajjar, R., Jarvis, D., & Gemmill-Herren, B. (2008). The utility of crop genetic diversity in maintaining ecosystem services. Agriculture, Ecosystems and the Environment, 123: 261-270.• Hobbs, R., & Morton, S. (1999). Moving from descriptive to prescriptive ecology. Agrofrestry Systems, 45: 43-55.• Hole, D., Perkin, A., Wilson, J., Alexander, I., Grice, P., & Evans, A. (2005). Does organic farming benefit biodiversity? Biological Conservation, 112: 113-130.• Jackson, W., & Piper, J. (1989). The Necessary Marriage Between Ecology and Agriculture. Ecology, 70(6): 1091-1093.• Jordan, C. (1995). Conservation: Replacing Quantity with Quality as a Goal for Global Management. Chichester, UK: John Wiley and Sons.• Jorgensen, S., & Nielsen, S. (1996). Application of ecological engineering principles in agriculture. Ecological Engineering, 7: 373-381.• Killham, K. (2011). Integrated soil management - moving towards globally sustainable agriculture. Journal of Agricultural Sciences, 149: 29- 36.• Lefory, E., Hobbs, R., OConnor, M., & Pate, J. (1999). What can agriculture learn from natural ecosystem? Agroforestry Systems, 45: 423-436.• MacRae, S., Hill, B., Henning, J., & Bentley, A. (1990). Policies, programs, regulations to to support the transition to sustainable agriculture in Canada. American Journal of Alternative Agriculture, 5: 76-92.• Main, A. (1999). How much biodiversity is enough? Agroforestry Systems, 45: 23-41.
  21. 21. References• Miller, F. (2008). After 10,000 Years of Agriculture, Whither Agronomy? Agronomy Journal, 100: 1-13.• Natarajan, M., & Wiley, R. (1986). The effects of water stress on yield advantages of intercropping systems. Field Crops Research, 13: 117-131.• Neher, D. (1999). Soil community composition and ecosystem processes. Agroforestry Systems, 45: 159-185.• Nielsen, S. (2007). What has modern ecosystem theory to offer cleaner production, industrial ecology and society? The views of an ecologist. Journal of Cleaner Production, 15: 1639-1653.• Paul, E., & Roberston, G. (1989). Ecology and Agricultural Sciences: A False Dichotomy? Ecology, 70(6): 1594-1597.• Roberston, G., & Swinton, S. (2005). Reconciling agricultural productivity and environmental integrity: a grand challenge for agriculture. Frontiers in Ecology and Environment, 3(1): 38-46.• Robertson, A. (2000). The Gaos Between Ecosystem Ecology and Industrial Agriculture. Ecosystems, 3: 413-418.• Rosset, P. (2000). Cuba: A Successful Case Study of Sustainable Agriculture. In F. Madgoff, J. Foster, & F. (. Buttel, Hungry for Profit: The Agribusiness Threat to Farmers, Food and the Environment (pp. 203-213). New York, NY: Monthly Review Press.• Shi, T. (2002). Ecolgical agriculture in China: briding the gap between rhetoric and practice of sustainability. Ecological Economics, 42: 359-368.• Stirzaker, R. (1999). The problem of irrigated horticulture: matching the biophysical efficiency with the economic efficiency. Agroforestry Systems, 45: 187-202.• Swinton, S., Lupi, F., Robertson, G., & Hamilton, S. (2007). Ecosystem services and agriculture: Cultivating agricultural ecosystems for diverse benefits. Ecological Economics, 64: 245-252.
  22. 22. Ecological Agriculture in ChinaHistorically Modern Reforms Reversion to Past Taoism – harmony Western practices Ecoagriculture – with nature adopted melding of past and present 4000 of years of Major impacts 51 counties have cultivation realized shown favourable improvement Soil fertility 35% of total land maintained experiencing Legal proposal desertification drafted to shut down GE rice
  23. 23. Ecological Agriculture in China