What 'yield' means and why farmers manage it (spec 5.1)
Yield is the amount of crop harvested; faster, healthier growth means a bigger yield.
Yield means the amount of useful crop a farmer harvests β for example the mass of tomatoes picked from a field or the number of lettuces grown in a season. Farmers naturally want to get the highest yield they can from their land.
The key idea of this whole topic is simple: a plant grows by photosynthesis, the process that makes glucose (food) using light, carbon dioxide and water. The faster a plant photosynthesises and the more minerals it has, the more it grows β and the more it grows, the higher the yield.
So to increase yield, farmers try to give crops the best possible conditions for photosynthesis and growth:
- enough light
- a warm enough temperature
- plenty of carbon dioxide
- enough water
- the right mineral ions in the soil
Two main methods are tested in this topic: growing crops inside glasshouses and polythene tunnels (which control the conditions), and adding fertilisers (which supply mineral ions).
Exam tip. When a question asks how a method increases yield, always connect it back to more photosynthesis β more growth β higher yield.
- Yield = the amount of useful crop harvested.
- More photosynthesis + more minerals β more growth β higher yield.
- Farmers manage light, temperature, COβ, water and minerals.
See the full worked example for managing the yield of crops β