Farming as an ecological system and as an economic system

Farming as an ecological system

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 products Market Cash

Waste products

Agricultural systems

Biotic

AboticAbotic

Biotic

Components of an ecosystem

Three major principles of ecosystem

• Nutrient cycling• Energy flow• Structure

Ecosystem - Nutrient Cycle

Ecosystem - Energy flow

Source: Law (2004)

EcosystemNutrient cycling, energy flow and structure

Ecological system• Manipulated ecosystem• For yields (desired products)• Provide the most favourable conditions for the plants and

animals he wishes to produce.

Agro-ecosystem VS natural ecosystem

Natural ecosystem Agro-ecosystem

Inputs Physical inputsThe SUN

Physical + Human inputs

Disposal of outputs Return to the ecosystem For sale

Roles of man Indirectly affect the input Control the inputs and processes

Nutrient cycling/ Flow of energy

Continuous Interrupted with energy subsidy in various formi.e. Chemical fertilizer

Crop/ Livestock selection and species diversity

Higher biodiversity Larger number of species

Lower biodiversity Monoculture/ Polyculture

Stability Stable Unstable

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

Energy efficiency

Source of Energy Example Energy 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 mostly Shifting cultivation in SE Asia, Pastoral nomads

16:1

High

Ecological system – Nutrient CycleNatural 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

Ecological system - StabilityNatural Agricultural 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

Farming as an economic system

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.

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?

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?

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.

• Decisions result in action which may result in land use patterns, wealth or poverty

• Wealth economic surplus innovation • Poverty stagnation

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

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