Basics of Fertilisers
What global factor increases the need for fertilisers?
Rising population
Which type of fertiliser provides exact nutrient ratios—organic or inorganic?
Inorganic fertilisers.
What does a fertiliser label like 15-5-20 represent?
Its N:P:K ratio (Nitrogen : Phosphorus : Potassium).
How do fertilisers contribute to soil degradation?
They acidify soil and reduce beneficial microorganisms.
What are controlled-release fertilisers designed to do?
Release nutrients slowly to reduce runoff and waste.
Explain how fertilisers help support modern farming systems
They replenish nutrients quickly so the same crops can be grown repeatedly.
Compare nutrient release in organic vs inorganic fertilisers.
Organic releases slowly & unpredictably; inorganic releases fast & precisely.
Why is choosing the correct NPK ratio important for crop yield?
Wrong ratios lead to weak plants, poor root systems, or low fruiting.
Explain how nitrate contamination harms human health.
It causes conditions like “blue baby syndrome” in infants.
Explain how the Rhizobium–legume relationship reduces fertiliser dependency.
Bacteria convert atmospheric N₂ into nitrates, naturally enriching the soil.