Agroecology: Principles and Practices


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A presentation written by Miguel Altieri, Professor of Agroecology at the University of California, Berkeley in the Department of Environmental Science, Policy and Management, with the participation of Angela Hilmi. You can choose to download the short or the long version; both of them are in Power Point format and available in English, French, Spanish and Portuguese download at

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Agroecology: Principles and Practices

  1. 1. AGROECOLOGY Principles and Practices (Long version) By Miguel Altieri With the participation of Angela Hilmi Design Francesca Lucci
  2. 2. Modern Practices - Interventionist paradigm - Therapeutic approach - Specialization/ - High import/ centralization high export System/ Community Erodes inherent pillar strengths Inherent Strengths of System
  3. 3. WATER CONTAMINATION Pesticides; Nittrates; Phosphates, Bacteria Dead Zones AIR EMISSIONS Methane; Ammonia; Notrous Oxide Carbon Dioxide SOIL LOSSES Erosion; Loss of organic matter and Carbon dioxide Above the cost of Food at the Checkout Counter DISAPPEARING WETLANDS Draining and Tilling; Dewatered Rivers; Impact on Species BIODIVERSITY LOSS Wildlife and habitat; Hedgerow and woodland loss; Bee colony decline; Vanishing Crops and Breeds HUMAN HEALTH Pesticides; Asthma; Bacteria and viral diseases; Antibiotic resistance; Mad Cow and E.Coli; Bbesity
  4. 4. Intensive agricutlure replaces ecological services Fertilizers Soils Crop genetic Commercial varieties in and species monoculture diversity Nutrient GroundWater water cycling pumping Climate Pest Honey Pesticides Pollination bees control Mechanization Domestic animals Feed lots AGRICULTURE Meat, grains, vegetables, fruits, seeds, fibers, fuels EXTERNALITIES: eutrophication, pollution; salinization; soil erosion and compaction, greenhouse Healthy ecosystems gas emissions, biodiversity loss, human health issues Monoculture landscapes Farmscapes, recreation, biodiversity
  5. 5. DFS: restoring ecological services in farms PLOT FIELD Polyculture; Plants and Animals Insectary Strips NUTRIENTS Crop Rotation/ Cover Crop WATER LANDSCAPE Crop Border/ Buffer Strips SOILS Riparian Corridors PEST CONTROL Nature Reserves POLLINATION
  6. 6. Ecology Anthropology Sociology Ethnoecology AGROECOLOGY Biological Control Ecological economics Basic agricultural sciences Principles Specific technological forms Traditional Farmers’ knowledge Participatory research in farmers’ fields
  7. 7. AGROECOLOGY  integrates natural and social processes joining political ecology, ecological economics and ethnoecology among the hybrid disciplines;  uses a holistic approach therefore it has long been considered as a transdiscipline as it integrates the advances and methods of several other fields of knowledge around the concept of the agroecosystem viewed as a socio-ecological system;  is not neutral and is self-reflexive, giving rise to a critique of the conventional agricultural paradigm;  recognizes and values local wisdom and traditions, creating a dialogue with local actors via participatory research that leads to a constant creation of new knowledge;  adopts a long-term vision that sharply contrasts with the short-term and atomistic view of conventional agronomy; and  is a science that carries an ecological and social ethics with a research agenda of creating nature friendly and socially just production systems.
  8. 8. THE HIDDEN CONNECTIONS Principles of Ecology Networks At all scales of nature, we find living systems nesting within other living systems – networks within networks. Their boundaries are not boundaries of separation but boundaries of identity. All living systems communicate with one another and share resources across their boundaries. Cycles All living organisms must feed on continual flows of matter and energy from their environment to stay alive, and all living organisms continually produce waste. However, and ecosystem generates no net waste, one species’ waste being another species’ food. Thus, matter cycles continually through the web of life. Solar energy Solar energy, transformed into chemical energy by the photosynthesis of green plants, drives the ecological cycles. Partnership The exchange of energy and resources in an ecosystem are sustained by pervasive co-operation. Life did not take over the planet by combat but by co-operation, partnership, and networking. Diversity Ecosystems achieve stability and resilience through the richness and complexity of their ecological webs. The greater their diversity, the more resilient they will be. Dynamic Balance An ecosystem is a flexible, ever-fluctuating network. Its flexibility is a consequence of multiple feedback loops that keep the system in a state of dynamic balance. No single variable is maximized; all variables fluctuate around their optimal values.
  9. 9. Agroecological principles underlying productivity, sustainability and resiliency of agroecosystems  Spatial and temporal genetic and species diversity at farm and landcape level  Crop and animal integration  Biologically active organic matter rich soils  Hi biomass recycling rates and tight nutrient cycles  Optimization of the use of space (agroecological redesign)
  10. 10. Agroecosystem Processes to Optimize • Organic matter accumulation and nutrient cycling • Soil biological activity • Natural control mechanisms (disease suppression, biocontrol of insects, weed interference) • Resource conservation and regeneration (soil, water, germplasm, etc) • General enhancement of agrobiodiversity
  11. 11. Sustainable agricultural systems are conceptualized here as being low in material input (pesticides, inorganic fertilizer, etc.) and high in information input (applied ecological knowledge of the system). High chemical input practices conceal and depreciate the importance of ecological processes occurring in agricultural systems. However, as pesticides, fertilizer, etc. are reduced, greater knowledge of the interaction occurring in agroecosystems is required for success. Furthermore, this knowledge must be applied in a practical manner to maintain agroecosystem productivity.
  12. 12. Input susbstitution vs agroecological approach • Symptoms • Root causes • limiting factors • processes • external inputs • interactions/synergy • maximize yields • stabilization • monoculture • diversification • ususally one product • multiple functions and products
  13. 13. The pillars of agroecosystem health Agroecological Principles Agroecosystem Design “Below ground” “Above ground” Habitat Management, Plant Diversification and enhancement of beneficial fauna Habitat Management Biota Activation and Diversification (Soil Organic Matter Nutrient Management) Crop Health Agroecosystem Health
  14. 14. The ecological role of biodiversity in agroecosystem function and the provision of ecosystem services by diversified farming systems (Lopez-Ridaura et al. 2002)
  15. 15. Rotational-intercropping design to reduce soil-nitrate losses
  16. 16. Biodiversity corridor in Fetzer Vineyard
  17. 17. Crop production Integrated System Animal production
  18. 18. This model shows an integrated barn with spatial and temporal design of crops, pasture, serials and trees. The pasture constitutes the changing phase of the rotation as grazing animals deposit manure improving soil fertility for the annual crops that use the nutrients thus representing the extracting phase of the rotation
  19. 19. An integrative scheme of peasant knowledge of Nature
  20. 20. Indigenous Mexican maize varieties
  21. 21. Features of appropriate technologies for poor farmers  Based on indigenous knowledge and rationale  Economically viable, accessible and based on local resources  Environmental sound, socially and cultural sensitive  Risk averse, adapted to heterogeneous circumstances  Enhance total farm productivity
  22. 22. Agroecological strategies Polycultures Organic amendments Animal integration Green manures Rotations
  23. 23. Finca “Del Medio” – José A. Casimiro Sancti Spíritus
  24. 24. Characteristics of an integrated farm Area (ha) 10 Energy (GJ/ha/yr) 50.6 Protein (kg/ha/yr) 867 People fed by produced energy (Pers/ha/yr) 11 People fed by produced protein (Pers/ha/yr) 34 Energy efficiency 30
  25. 25. Findings from a study of MASIPAG organic farmers in the Philippines  Food security is significantly higher for organic farmers.    Organic farmers have grow 50% more crops thus eating more diverse, nutritious and secure diet.  Organic farms exhibit better soil fertility, less soil erosion, increased tolerance of crops to pests and diseases and climate change  Health outcomes were also substantially better for the organic group.
  26. 26. 1: org.=conven. < l: conven. mayor que org. >1: org. mayor que conven. Casi 300 estudios comparativos de agricultura orgánica/agroecológica y agricultura convencional
  27. 27. Agroecology  is socially activating as its diffusion requires constant farmers participation;  is a culturally acceptable approach as it builds upon traditional knowledge and promotes a dialogue of wisdoms with more western scientific approaches;  promotes economically viable techniques by emphasizing use of indigenous knowledge, agrobiodiversity and local resources, avoiding dependence on external inputs;  is ecologically sound as it does not attempt to modify the ergy and efficiency of existing production systems, but rather tries to optimize their performance promoting diversity and synergies
  28. 28. The Campesino a Campesino Movement • The Campesino a Campesino movement is an extensive grassroots movement in Central America and Mexico. • It is a cultural phenomenon, a broad-based movement with campesinos as the main actors • The Campesino a Campesino movement is an excellent example of how alternative technologies and practices can be disseminated bypassing "official channels". • It is a bottom up, horizontal mechanism for knowledge sharing and technology transfer
  29. 29. Pilars of food sovereignty Agroecological strategies Social movements Land reform Access to land, water, seeds State support Markets, Credit, extensions, Research etc
  30. 30. Agroecology, resilience and the three types of sovereignty to be reached in a rural community.
  31. 31. Hypothetical threshold values established for an agricultural community for each type of sovereignty
  32. 32. Alta Low external inputs, high recylcling rates, crop –livestock integration High inputs, industrial monocultures Low High Eficiency Baja Productivity Agroecosystem Diversity Low external inputs, diversified with low levels of integration Specialized systems with low external inputs Medium-Low Medium Alta Baja
  33. 33. The basic requirements of a Viable and durable agricultural system … The basic requirements of a Viable and durable agricultural system capable of confronting the challenges of the 21st century while carrying out its productive goals within certain threshold established locally or regionally.
  34. 34. Thank you for your attention!