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The production of plants and animals for food ultimately depends on the factors that control plant growth:

• light availability
• available nutrients
• water in the soil
• competition with other plants

The area available to grow crops is limited. Simply growing more crops is not the answer. Increasing food production can only achieved by improving efficiency. This may be achieved by adopting one or more of the following practices:

• Control of limiting factors. For example, if growing crops in an area short on minerals, these can be provided by the use of fertilisers.
• Planting strains of crops that have a higher yield.
• Removing competition from weeds and diseases by using pesticides, fungicides and herbicides.
• Developing pest-resistant crops.

Production of livestock is less efficient than growing crops. About 90 per cent of energy is lost between trophic levels, so raising animals for meat requires much more energy per unit area than growing crops. As well as this it is very water intensive.

However, livestock production is often possible in habitats unsuitable for growing crops.

People should be encouraged to eat more vegetables and cut down on meat to protect our food security and be more sustainable.