ECOLOGICAL PRINCIPLES IN FARM DESIGN: farming in ”nature’s image”

ECOLOGICAL PRINCIPLES IN FARM DESIGN

RELEVANT LITERATURE Gliessman S 2004 Agroecology and agroecosystems. In: Agroecosystems Analysis, D. Rickerl and C. Francis, editors. American Society of Agronomy, Madison, Wisconsin, USA. 43: 19–29 [book used in summer travel class, Iowa State U] Gliessman S 1998 Agroecology: ecological processes in sustainable agriculture. Lewis Publishers, Boca Raton, Florida; also London, New York, Washington [most popular US text] Gliessman S 2007 Agroecology: the ecology of sustainable food systems. Lewis Publishers, CRC Press, Boca Raton, Florida; also London, New York, Washington [new edition of same text] Soule J And J Piper 1991 Farming in nature’s image: an ecological approach to agriculture. Island Press, Washington, DC [original book on Land Institute research and perspective] ECOLOGICAL PRINCIPLES IN FARM DESIGN

WHY PAY ATTENTION TO ECOLOGICAL PRINCIPLES? ecological structures and functions are building block on which economic and social sustainability depend ECOLOGICAL PRINCIPLES IN FARM DESIGN Agroecosystem context and foundation Socio-economic Natural resources Agroecosystem structure and function Socio-economic components Ecological components Indicators of sustainability Socio-economic parameters Ecological parameters Conditions of sustainability (Adapted from Gliessmann 1998)

KNOWLEDGE BASE Natural ecosystems Reference systems for understanding generic ecological structures and functions: generalizable principles ecological basis for sustainability in a particular location: each farm is unique Traditional (local or indigenous) ecosystems having passed the test of time Examples of sustainable co-evolution of human culture and its local environment ECOLOGICAL PRINCIPLES IN FARM DESIGN

ECOSYSTEM a functional system of complementary relations between living organisms and their environment, delimited by arbitrarily chosen boundaries, which in space and time appears to maintain a steady yet dynamic equilibrium (Odum 1996; Gliessman 1998) ECOLOGICAL PRINCIPLES IN FARM DESIGN

ECOLOGICAL PRINCIPLES OF NATURAL ECOSYSTEMS: ENERGY Flows as a result of complex sets of trophic interactions Certain amounts are dissipated at different stages along the food chain [10:1 ratio across trophic levels] Greatest amount moving along the detritus pathway (Odum, 1971) Energy sources in natural ecosystems are renewable ECOLOGICAL PRINCIPLES IN FARM DESIGN

ECOLOGICAL PRINCIPLES OF NATURAL ECOSYSTEMS .....NUTRIENTS Small inputs through hydrobiogeochemical processes; e.g., precipitation N2 fixation weathering of minerals Internal circulation through complex sets of interconnected cycles Most often bound in organic matter (Borman and Likens 1967) Biological components are very important flow rate regulators, e.g., decomposers mycorrhiza plants In mature (climax) ecosystems, there are minimal losses, which are in balance with the small inputs ECOLOGICAL PRINCIPLES IN FARM DESIGN

...NUTRIENTS: Spatial relationships of the trophic pyramid ECOLOGICAL PRINCIPLES IN FARM DESIGN Plants Animals Humans Early agriculture (till 18th – mid-19th Century) Urbanising agriculture (till mid-20th century) Industrial agriculture (since mid-20th century) (From Magdoff et al. 1997) {Magdoff,}

ECOLOGICAL PRINCIPLES OF NATURAL ECOSYSTEMS.....DIVERSITY Succession through time tends toward establishment of the most complex structure and function biologically possible within the limits set by the environment Diversification of trophic interactions niches Maximum exploitation of available resources and niches Control of population levels of the various organisms A degree of resistance to all but very damaging perturbations, i.e., fluctuation around a dynamic equilibrium, the fluctuations often causing increased diversity and productivity ECOLOGICAL PRINCIPLES IN FARM DESIGN

.....DIVERSITY ECOLOGICAL PRINCIPLES IN FARM DESIGN

SUMMARY: ECOLOGICAL PRINCIPLES How did physical & biological structure relate to the functions you observed on project farms? What were the major energy sources on your project farms? What were major losses of energy? List and describe principle nutrient sources on your project farms. List also major nutrient losses. What elements and functions of natural ecosystems were operating on project farms? What were the major types of biodiversity observed on the farms you visited? ECOLOGICAL PRINCIPLES IN FARM DESIGN

SUMMARY: MORE QUESTIONS--ECOLOGICAL PRINCIPLES How would you apply ecological structure and function to design a diverse agroecosystem with crops & animals? What strategies would you employ to increase efficiency of energy use and minimize loss from the farm? In what ways could you increase nutrient cycling and thus reduce productions costs on the farm? What parallels do you see between the role of a keystone predator in the natural ecosystem and the role of people in agroecosystems? ECOLOGICAL PRINCIPLES IN FARM DESIGN