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What is an agroecosystem?
• Biophysical and socioeconomic components
• Boundaries and hierarchies• Structure and function• History and legacy
Agroecosystem checklist (1) (Brookfield et al., 2002)
• Management: field types and edges; site and field surface preparation; soil and water conservation; soil fertility maintenance; planting materials; cropping patterns and rotations; weeds and weeding, pests and diseases; crop harvesting, processing, and storage; livestock; woodlots; fallow areas; wild areas
Agroecosystem checklist (2) (Brookfield et al., 2002)
• Biophysical structure and processes: physical features at landscape and field levels; soil characteristics; soil erosion, degradation, and enhancement; microclimates
Agroecosystem checklist (3) (Brookfield et al., 2002)
• Organization: land tenure; farmer gender; land ownership history; crop and tree ownership; land-use history; land-use intentions; types of livestock; off-farm employment; food security; water supplies; fuel supplies; labor supplies; transportation networks; marketing; decision-making processes
How do trees and other perennials fit into agroecosystems?
Agroecosystems are often studied as part of an effort
to change them
The Evolution of Farming Systems Research (Hart, 2000)• Scale of target systems: from crop
populations to whole farms to communities and watersheds
• System performance criteria: from production to stability to sustainability
• Targeted beneficiaries: from ‘small farmers’ to men and women to future generations
• Relationships: recognition of hierarchies
Sustainability in the Context of Farming Systems Research
(Hart, 2000)• A group of production technologies (e.g.
cover crops)• Maintenance of the natural resource base
upon which production depends• A measure of intergenerational equity
Participatory Rural Appraisal
• ‘Empowering rather than extractive’• Outsiders as facilitators rather than
investigators• Information owned, analyzed, and used by
local people rather than outsiders• Often conducted by NGOs rather than
universities and government agencies
Prototyping Integrated and Ecological Arable Farming Systems
(Vereijken, 1997)• Establish a hierarchy of objectives• Transform objectives into quantifiable
performance parameters• Design and test prototypes that link
socioeconomic and biophysical objectives with multi-faceted farming methods
• Place prototypes on pilot farms• Refine and adapt prototypes• Disseminate prototypes to other farms
Components of a farm’s ‘identity card’ (Vereijken, 1997)
• Abiotic environmental characteristics (soil, water, and air quality)
• Non-agricultural species diversity (ecological infrastructure)
• Food supply (quality and quantity)• Health and safety (including pesticide
impacts)• Income and profit (farm and regional levels)
Farming methods for I/EAFS• Multifunctional crop rotation• Nutrient balance• Ecological infrastructure: restoration
and maintenance of landscape elements
• Farm structural optimization (land, labor, capital goods, technologies)
Principles of Agroeocosystem Analysis (Conway, 1986)
• It isn’t necessary to know everything about an agroecosystem in order to produce a realistic and useful analysis (‘optimal ignorance’).
• Understanding the behavior and important properties of an agroecosystem requires knowledge of only a few key functional relationships.
• Producing significant improvements in the performance of an agroecosystem requires changes in only a few key management decisions.
• Identification and understanding of these key relationships and decisions requires a limited number of key questions are defined and answered.
Tractors and water buffaloes in Sri Lanka
(Senanayake, 1984; Conway, 1986)
• Land area for rice vs. land for wallows and non-crop vegetation
• Protein sources: buffalo milk, fish• Refugia for fish, snakes, lizards• Bund-boring crabs• Rats• Mosquitoes and malaria
Agroecosystem Analysis: Tools (Conway, 1986)
• Diagrammatic history of the site, including major events• Maps and transects showing important features, including topography,
soils, land use, problems, opportunities• Seasonal calendars for climate, crop sequences, livestock, non-farm
activities, labor requirements, capital requirements, income, monthly prices
• Long-term graphs showing prices, yields, acreages, population trends (births, deaths, emigration, immigration)
• Bar diagrams showing sources of farm income, expenses on different types of production inputs, etc.
• Flow diagrams showing production and marketing chains, flows of income
• Decision trees depicting choice points, key factors• Venn diagrams depicting overlapping institutions affecting decision-
making
A tentative plan (I)1. Develop awareness of ecological,
agronomic, and socio-economic components
2. Identify information needs and form information gathering groups
3. Identify tools for organizing and presenting information
4. Meet with farmers at ISU and/or on farm5. Assemble information, by groups
A tentative plan (II)6. Present information to classmates at debriefing
following farm visits7. ‘Triangulate’ to determine accuracy of information8. Assemble conceptual models of farms as natural
resource/human activity systems: system boundaries, components, interactions, feedbacks, control points
9. Identify key questions, hypotheses, and possible changes
10. Assess impacts of proposed changes: ecological, agronomic, socioeconomic
Some focal areas• Natural resources: soils, water sources and drainage, water
quality, non-cultivated species, agricultural and non-agricultural land use
• Crop and livestock systems: species, synergies and conflicts, economics, nutrient dynamics, pest management systems, calendars, buildings and machinery, product identity, target markets
• Family: structure, gender issues, needs, goals, constraints, decision processes, values, off-farm jobs, land tenure, credit and debt, assets
• Local community: neighbors, medical and educational services, social network, labor sources
• Private and producer organizations: inputs, marketing channels, consultants, financing, information
• Government: subsidies, quality assurance, regulations, information
• Local and regional history and future trajectories
Tasks• Identify information gathering groups• Specify preferences for groups• Develop questions and framework for
interviews and on-farm surveys