Nutrients required by plants

1. Importance of Nutrients in Soil

• Fertilisers are needed due to:
  • Population growth → More food is required.
  • Decreasing agricultural land → Less land must produce more food.
• Plants absorb nutrients from the soil, but these nutrients must be replenished using fertilisers.

2. Types of Nutrients Required by Plants

Category	Nutrient Type	Examples	Source	Availability
Primary Nutrients	Carbon $(C)$ Hydrogen $(H)$ $**Oxygen**$(O)$	Air and water	From $CO₂$ in air and $H₂O$ from soil	Sufficient
Macro Nutrients	Nitrogen $(N)$ Phosphorus $(P)$ Potassium $(K)$	Fertilisers	Absorbed from soil	Depletes over time (requires fertilisers)
Secondary Nutrients	Calcium $(Ca)$ Magnesium $(Mg)$ Sulphur $(S)$	Soil minerals	Absorbed through roots	Sufficient
Micro Nutrients (Trace Elements)	Copper $(Cu)$ Iron $(Fe)$ Manganese $(Mn)$ Zinc $(Zn)$	Soil	Absorbed through roots	Sufficient

3. Key Definitions

• Promote: Help or encourage a process.
• Essential Nutrient: A nutrient needed by plants to grow.
• Inorganic Compound: A non-living substance (e.g., minerals in fertilisers).
• Mineral: A natural, solid inorganic substance found in soil.
• Sufficient: Enough to meet plant needs.

4. Interesting Facts

• Bone meal is made from ground-up animal bones.
• Blood meal is dried animal blood, rich in nitrogen.
• Granite meal is powdered granite rock, used as a soil amendment.

5. Key Takeaways

• Primary nutrients come from air and water, while macro and micro nutrients come from soil.
• Nitrogen, phosphorus, and potassium are the most important fertiliser nutrients.
• Fertilisers help maintain soil fertility and ensure healthy plant growth.