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
Why do many fish die as a result of eutrophication ?
The aerobic bacteria uses up their oxygen
What fertilisers can ammonia make ?
Ammonium sulphate
Ammonium nitrate
What method is used to make fertilisers ?
Titration
Step 1 of making a fertiliser is ?
Fill a buttered with an acid
What must you do with the alkali during the making of a fertiliser ?
Measure some using a measuring cylinder and add it to the conical flask
What else do you add to the conical flask ?
Indicator
After you’ve added indicator what should you do?
Allow the acid to run from the bursts into the alkali until the indicator says its been neutralised
What do you need to do to get solid crystals ?
Gently evaporate the solution until only a little bit is left and leave it to crystallise
