Excessive use of fertiliser and the environment

1.1 Groundwater Contamination

• Leaching: Fertilisers dissolve in water and seep into the ground, contaminating underground water sources.

1.2 Soil Acidification

• Overuse of fertilisers lowers soil $pH$, making the soil acidic.
• Many plants struggle to grow in acidic soil, reducing crop yield.

1.3 Invasive Plant Growth

• Excess nutrients encourage rapid growth of invasive plant species.
• Indigenous (native) plants die because they cannot compete for nutrients and space.

1.4 Eutrophication (Nutrient Pollution in Water)

• Fertilisers washed into rivers and dams cause excessive plant and algae growth.
• Algae die and decompose, leading to:
  • Bacteria feeding on algae and using oxygen.
  • Oxygen depletion, causing fish and other aquatic life to die.

1.5 Harmful Effects on Humans

• High nitrate levels in drinking water reduce haemoglobin's ability to carry oxygen, leading to blue baby syndrome in infants.

2. Eutrophication: Causes, Effects, and Solutions

Cause	Effect	Solution
Waste from farms & industries enters rivers and groundwater.	Algal bloom (rapid algae growth).	Strict waste control to prevent pollution.
Excessive use of fertilisers.	Algae die → Bacteria use up oxygen.	Test soil before fertiliser use to apply only the correct amount.
Animal waste (urea, ammonia) in water sources.	Oxygen levels drop → Fish and aquatic life die.	Control animal waste in feeding and milking areas.
Loss of indigenous plants.	Erosion increases as soil becomes unstable.	Plant indigenous vegetation along rivers to reduce erosion.
Disruptions in ecosystems.	Bird and insect species leave affected areas.	Protect natural wetlands that filter out excess nutrients.

3. Key Takeaways

• Overuse of fertilisers harms the soil, water, and ecosystems.
• Eutrophication leads to dead zones in water, killing aquatic life.
• Sustainable fertiliser use and proper waste management can reduce environmental damage.