Agroecology and Agroecosystems By Stephen R. Gliessman

1. Agroecology and AgroecosystemsBy Stephen R. Gliessman Jeremy Nelson

2. Intro • Agriculture • more than an economic activity to maximize production and profit • Environmental and social components too • Sustainability as a means to balance the interactions • Agroecology as a way to achieve sustainability

3. Agroecology • Agriculture as a stream, individual farms are points along it • Upstream impacts on farms • Labor availability and cost • Market access for goods produced • Legislative policies – water & pesticide use, animal care • Downstream effects of farms • Soil erosion and groundwater depletion • Pollution of water, air, soil, food

4. Agroecology cont. • Ecosystems: • Functional system of relations between organisms and environment • Maintain relative equillibrium; thus sustainable • Agroecosystems work to balance biological, physical, chemical, ecological, cultural interactions • To achieve andsustain yields • Created through human manipulation of an environment for agproduction

5. Agroecosystems cont. • Created through human manipulation of an environment for agproduction • Changes key aspects of the natural ecosystem; called emergent qualities • 4 key qualities • Energy flow • Nutrient cycling • Population regulation • Dynamic equilibrium

6. Application • Indigenous farm systems are sustainable agroecosystems • Example of how cultures and local environments coevolved to balance all the needs of people • Ecological, technological, soio-economic • Illustrates importance of… • Intimate knowledge of local ecology • Perceiving the farm as part of a much larger system

8. Conclusion • Agricultural systems cannot be regarded solely as production driven by economic forces • Nor can we disregard interrelations of agriculture and ecosystems • “By properly selecting and understanding the ‘upstream’ inputs into agriculture, we can be assured that what we send ‘downstream’ will promote a sustainable future” (Gliessman 2004: 113)