Alternatives to inorganic fertilisers

1. Organic Fertiliser Alternatives

To reduce environmental harm from inorganic fertilisers, alternative organic fertilisers can be used:

• Bone meal (crushed animal bones).
• Animal manure (livestock waste).
• Natural plant compost (decomposed plant material).
• Bat guano (bat faeces).
• Fish emulsions (liquid fertiliser made from fish).
• Kelp meal (seaweed-based fertiliser).

2. Advantages and Disadvantages of Organic Fertilisers

Advantages	Disadvantages
Slow nutrient release prevents contamination of groundwater.	Not available in large quantities for large-scale farming.
Cost-effective – often free or inexpensive.	Lower nutrient content requires larger amounts to be applied.
Environmentally friendly – decomposes naturally.	Slow release of nutrients may harm plants if nutrients are not available when needed.

3. Sustainable Use of Fertilisers

Farmers must balance fertiliser use to prevent negative environmental effects while ensuring good crop production.

Precautions to Prevent Environmental Harm

• Use fertilisers sparingly – do not overapply.
• Use precision application methods (e.g., computer-controlled fertiliser distribution).
• Redirect water runoff to reservoirs to prevent eutrophication in rivers and dams.

4. Important Industrial Processes in Fertiliser Production

4.1 Industrial Production of Nitric Acid

• Process: Ostwald process.
• Equation: (Production of ammonium nitrate fertiliser from nitric acid.) $HNO_3 + NH_3 \rightarrow NH_4NO_3$

4.2 Industrial Production of Sulphuric Acid

• Process: Contact process.
• Catalyst: Vanadium pentoxide $(V₂O₅).$
• Reaction Type: Exothermic $(ΔH < 0).$
• Fertiliser Formed: Ammonium sulphate $(NH₄)₂SO₄.$

5. Impact of Fertiliser Use

Positive Effects

✅ Increases crop yield → ensures food security.

✅ Creates jobs in fertiliser production and sales.

✅ Boosts economy by improving agricultural productivity.

Negative Effects

❌ Eutrophication from fertiliser runoff into water sources.

❌ Blue baby syndrome from excessive nitrates in drinking water.

❌ Soil pH imbalance, reducing long-term fertility.