Terrestrial food production systems
Big idea: Agriculture is a human-managed ecosystem designed to maximize food production. We manipulate energy flows and nutrient cycles to channel more productivity into food for humans — but this has environmental costs.
Agriculture as a system
Agricultural systems have inputs, outputs, stores, and flows — just like natural ecosystems, but heavily modified by humans.
Inputs
- Solar energy
- Seeds / livestock
- Fertilizers (N, P, K)
- Pesticides / herbicides
- Water (irrigation)
- Fossil fuels (machinery)
- Labour
Outputs
- Food (crops, meat, dairy)
- Animal feed
- Biofuels
- Waste (manure, crop residues)
- Pollution (runoff, emissions)
- Soil erosion
Types of terrestrial food production
- Crop farming — cereals (wheat, rice, maize), vegetables, fruits
- Livestock farming — cattle, pigs, sheep, poultry
- Mixed farming — crops and livestock together
- Agroforestry — trees integrated with crops/livestock
- Plantation agriculture — large-scale monocultures (palm oil, rubber)
Agriculture accounts for ~70% of global freshwater use, ~30% of global land area, and ~25% of greenhouse gas emissions. It is the largest human impact on the planet!
IB-style question — a food production system's inputs & outputs
Outline the main inputs and outputs of a commercial cereal (e.g. wheat) farming system. [4]
How the marks are earned
- Inputs
• seeds, fertilisers, pesticides, irrigation water
• machinery, fuel, labour - Outputs
• grain (food) + straw (by-product)
• unwanted: nutrient runoff, greenhouse gas emissions
Final answer
Include at least one unwanted output — examiners expect you to show the system has negative outputs too.