C2G - Why Do We Need Fertilisers Flashcards
What happens if plants don’t get enough of the 3 essential elements ?
Their growth and life processes are affected
What are the three essential elements in fertilisers ?
Nitrogen
Phosphorus
Potassium
Why could elements be missing from the soil ?
They may have been used up by a previous crop
What do fertilisers do in terms of the elements ?
Replace missing ones
What do fertilisers increase ?
The crop yield
What must happen before the plant takes in the fertiliser ?
Dissolve in water
What’s an advantage of fertilisers ?
More crops to help feed to increasing world population
Disadvantage of fertilisers ?
Risk of killing aquatic life and polluting our waters
What part does rain water play in the process of eutrophication ?
It washes excess fertilisers off the fields into rivers and streams
When fertilisers are washed into streams what happens ?
The level of nitrates and phosphates in the water increases
What happens to the algae in the waters ?
It uses the nutrients to multiply rapidly creating an algae bloom
Why is an algae bloom bad ?
It blocks off light to river plants below
Why do river plants below algae die ?
Can’t access sunlight to photosynthesise
What do the aerobic bacteria do ?
Feed on the dead plants and multiply
What happens as the bacteria multiply ?
They use up all the oxygen
