C2g: Fertilisers and Crop Yeild:
Fertilisers are chemicals that give plants essential chemical elements needed for growth. They:
- make crops grow faster and bigger
- increase the crop yield
As world populations rise, fertilisers can increase food supplies.
It can also cause problems such as the death of problems such as the death of animals in waterways, which is known as eutrophication.
Eutrophication: the growth and decay of aquatic plants e.g algae, due to increases levels of nutrients in the water (caused by fertilisers) which results in oxygen levels dropping so that fish die out.
The 3 main essential elements found in fertilisers are nitrogen (N), phosphorus (P) and potassium (K). Urea can also be used.
Fertilisers MUST be soluble in water so that they can be taken in by the roots of plants.
HT: Fertilisers increase crop yield by:
- replacing essential elements in the soil that have been previously been used up.
- providing nitrogen as soluble nitrates which are…