Soil Fertility

Soil fertility is the soil’s ability to consistently support plant growth and high yields by providing all necessary plant nutrients in the correct proportions.

Success Criteria

• Investigate differences between fertile and infertile soils.
• State ways of maintaining soil fertility.

Differences Between Fertile and Infertile Soils

• Fertile Soil:

  • Contains all essential plant nutrients.
  • Has appropriate depth for the crop.
  • Is well aerated.
  • Is well-drained.
  • Is free from soil-borne diseases.

• Infertile Soil:

  • Lacks one or more essential plant nutrients.
  • Is shallow for the crop.
  • Is poorly aerated.
  • Is poorly drained.

Factors Contributing to Soil Fertility

• Soil Depth: Deep soil supports root growth and development.
• Aeration: Well-aerated soils promote root growth and microbial activity.
• Drainage Ability: Good drainage allows air into the soil; poor drainage can suffocate roots.
• Freedom from Pests and Diseases: Healthy soil is free from disease-causing organisms like nematodes, fungi, and bacteria.
• Right Soil pH: A neutral pH (around 7.5) is ideal as most essential nutrients are available and plants grow well.

How Soil Fertility is Lost

• Soil Erosion: Removes fertile topsoil.
• Leaching: Washes away plant nutrients.
• Hard Soil Pan Development: Interferes with water drainage.
• Crop Removal: Depletes nutrients from the field.
• Very Low or High Soil pH: Affects nutrient availability.

Ways of Maintaining Soil Fertility

• Applying Fertilizers:
  • Organic and inorganic fertilizers replace lost nutrients.
  • Organic matter improves soil structure and controls acidity.
  • Lime fertilizers (CAN) reduce soil acidity.
• Proper Soil Drainage: Ensures adequate soil water for plants.
• Practicing Crop Rotation:
  • Disrupts pest build-up.
  • Helps bring back leached nutrients by including deep-rooted crops.
  • Controls soil erosion when cover crops are used.
• Controlling Soil pH: Maintain pH within the range of 5.5 to 7.5 for optimal crop growth.
• Timely Weed Control:
  • Weeds absorb plant nutrients.
  • Weeds harbor pests and disease-causing organisms.
• Controlling Soil Erosion: Prevents the removal of fertile topsoil and the loss of plant nutrients.