Why food production needs to increase
The human population is growing rapidly, increasing the demand for food. Arable land is limited, so farmers must produce more food from the same area. This is achieved through intensive farming methods that maximise yield per unit area.
However, intensive farming can cause environmental problems including soil degradation, water pollution, loss of biodiversity and habitat destruction. Balancing food production with environmental protection is a key challenge.
Fertilisers
Fertilisers provide essential mineral ions that plants need for growth: nitrates (for amino acids and proteins), phosphates (for DNA and cell membranes) and potassium (for enzyme function). Adding fertilisers replaces minerals removed from the soil when crops are harvested.
Overuse of fertilisers can cause eutrophication if excess minerals are washed into waterways by rain (leaching). Organic fertilisers (manure, compost) release minerals slowly and improve soil structure but are less concentrated than artificial (inorganic) fertilisers.
Pesticides and biological control
Pesticides are chemicals that kill organisms that damage crops. Herbicides kill weeds that compete with crops for light, water and minerals. Insecticides kill insect pests that eat or damage crops. Fungicides kill fungi that cause plant diseases.
Biological control uses natural predators, parasites or diseases to control pest populations instead of chemicals. For example, introducing ladybirds to control aphid populations on crops. Advantages include no chemical pollution and the control is self-sustaining. Disadvantages include: the introduced species may not eat only the target pest, it may become a pest itself, and it is slower and less predictable than chemical control.
Other methods to increase yield
Selective breeding produces crop varieties with higher yield, disease resistance or drought tolerance. Greenhouses allow controlled conditions (light, temperature, CO2) to maximise photosynthesis rates. Irrigation provides water in dry areas.
Monoculture (growing one crop over a large area) is efficient for planting and harvesting but reduces biodiversity and makes the crop vulnerable to a single disease. Crop rotation (growing different crops in successive years) helps maintain soil fertility and break disease cycles.