1. Soil Nutrients Water Sun Air Energy Carbon, Oxygen Humans Labor: Collecting Processing Useful plant Useless plant Foraging Ecosystem Nutrients Fibers Drugs Decorations Etc.

2. Soil Nutrients Water Sun Air Energy Carbon, Oxygen Humans Labor: Clearing Burning Planting Fencing Weeding Harvesting Pest Control Storage Etc. Useful plant Useless plant Shifting Agricultural Ecosystem Nutrients Fibers Drugs Decorations Etc.

3. Fallow area Nutrients Water Sun Air Energy Carbon, Oxygen Humans Labor: Clearing Burning Planting Fencing Weeding Harvesting Pest Control Storage Etc. Useful plants Useless plant Shifting Agricultural Ecosystem Nutrients Fibers Drugs Decorations Etc. Farmed area Decomposition Ashes Less recently farmed More recently farmed

4. Sun Air Energy Carbon, Oxygen Humans Labor energy: Plowing Harrowing Planting Fencing Weeding Harvesting Pest Control Storage Etc. Useful plants (crops) Intensive Agricultural Ecosystem Nutrients Fibers Drugs Decorations Etc. FARMLAND Nutrients Water source Irrigation Animals Traction energy Manure (nutrients) Labor energy

5. Sun energy: Plowing Harrowing, Planting Fencing, Weeding Harvesting, Pest Control, Storage, etc. Industrial Monocrop Agricultural Ecosystem FARMLAND Air Energy Carbon, Oxygen Humans Single crops Nutrients Water source Irrigation Fossil Fuel Machinery Fertilizer Nutrients $ -cides Exchange Value Consumer goods

6. Agricultural Intensification Foraging Shifting Agriculture Intensive Agriculture Energy Input per unit of land Energy output per unit of land Net energy/ land Output/input ratio Poplation density Surplus

7. Agricultural Intensification