1. Farming as an ecological system and as an economic system

2. Farming as an ecological system

3. Manipulated ecosystem (Farming) Inputs from the physical environment Solar energy / temperature Rainfall / moisture Topography / relief Soil Plant nutrients Inputs from the human environment Labour Cultural values Transport Planting materials Technology Government influence Capital / equipment Agricultural productsMarketCash Waste products Agricultural systems Biotic Abotic Biotic

4. Components of an ecosystem

5. Three major principles of ecosystem Nutrient cycling Energy flow Structure

6. Ecosystem - Nutrient Cycle

7. Ecosystem - Energy flow Source: Law (2004)

8. Ecosystem Nutrient cycling, energy flow and structure

9. Ecological system Manipulated ecosystem For yields (desired products) Provide the most favourable conditions for the plants and animals he wishes to produce.

10. Agro-ecosystem VS natural ecosystem Natural ecosystemAgro-ecosystem InputsPhysical inputs The SUN Physical + Human inputs Disposal of outputsReturn to the ecosystemFor sale Roles of manIndirectly affect the inputControl the inputs and processes Nutrient cycling/ Flow of energy ContinuousInterrupted with energy subsidy in various form i.e. Chemical fertilizer Crop/ Livestock selection and species diversity Higher biodiversity  Larger number of species Lower biodiversity  Monoculture/ Polyculture StabilityStableUnstable

11. Ecological system – Energy Flow Energy efficiency Energy Yield Ratio=energy output / energy input The higher the energy yield ratio, the more the efficient the ecological system

12. Energy efficiency Source of EnergyExampleEnergy Yield Ratio High Energy system Solar energy Vast inputs of fossil fuels Farms in USA, Western Europe…. 0.38:1 Low Medium Energy system Energy input from the sun, wind & use of animals Wet rice cultivation in Asia 4:1 Medium Low Energy System Solar energy mostlyShifting cultivation in SE Asia, Pastoral nomads 16:1 High

13. Ecological system – Nutrient Cycle Natural Agricultural system Nutrients circulate within the ecosystem Removed entirely by prolonged cropping without compensating fertilizer input Nutrients are replaced again and again from different parts of ecosystem Heavily subsidized by input of chemical fertilizers Unavailable or accumulate to toxic level

14. Ecological system - Stability NaturalAgricultural system  Solar energy drive energy flow and nutrients cycle  Complex ecological linkages  Large biodiversity  self-maintained and stable  solar energy + human energy inputs  Energy flow and nutrients cycle  Fewer crops and animals or even monoculture  maintained by human effort  unstable

15. Farming as an economic system

16. Economic system Inputs as capital and human effort –Investment (inputs) Form of money Form of labour Outputs as financial gain Farmers need to make decision about –How much to invest and; –What aspects they are going to invest.

17. Economic system – decision making Key questions –What to produce? –How much to produce? –How to produce? –How much to invest? –What to lease? –How much to lease? –Where and how to buy? –Where and how to sell?

18. Economic system – decision making Result of decision by farmers –land use, cropping, use of biological inputs, total outputs and farming method and pattern…… Final goal  profit satisfaction or maximization?

19. Economic system – decision making Reasons: –Imperfect information –Lack of capital –Social customs may work against improvement –Personal characteristics Farmers are satisfiers Farmers may be conservative and consider a low degree of risk Farmers don’t want the extra work and they want to have more leisure time.

20. Decisions result in action which may result in land use patterns, wealth or poverty Wealth  economic surplus  innovation Poverty  stagnation

21. Economic system – decision making Papua New Guinea –Subsistence economy –Farmers –Minimum investment (human and cultural inputs) –For tribal or village consumption –Localize –Response to natural conditions Australia –Commercial economy –Entrepreneurs –Heavy investment (human and cultural inputs) –For sale (foodstuff, industry, urban) –Globalize –Response to markets

22. Shifting cultivation  primitive  only a small patch of forest is cleared  fallow period allow the forest to regenerate and fertility of the land to be restored  Poses little threat to ecosystem