BIOLOGY

Soil Nutrients And Plant Growth

Complete nutrient solution
Solution lacking nitrogen
Solution lacking sulfur
Tap water
Distilled water
Germinated seed
Introduction
Materials
Instructions

For plants to germinate and then grow strongly, they require sufficient water and energy from sunlight. For continued growth and strength, the roots need to take up nutrients from the soil. These nutrients are inputs into the soil system from the weathered rock, washed in by the rain or washed downwards by leaching of the humus. In this experiment, you will find out which nutrients are most important for plants like peas or scarlet runners.

  • Per group:
    • germinated bean seeds
    • 5 test tubes
    • distilled water
    • tap water
  • Complete nutrient solution:
    • 10 g calcium nitrate
    • 2.5 g potassium phosphate
    • 2.5 g magnesium sulfate
    • 2.5 g potassium nitrate
    • 0.5 g of ferric chloride
    • 1 liter distilled water
  • Nutrient solution lacking nitrogen:
    • 10 g calcium chloride (instead of calcium nitrate)
    • 2.5 g potassium phosphate
    • 2.5 g magnesium sulfate
    • 2.5 g potassium nitrate
    • 0.5 g of ferric chloride
    • 1 liter distilled water
  • Nutrient solution lacking sulfur:
    • 10 g calcium chloride (instead of calcium nitrate)
    • 2.5 g potassium phosphate
    • 2.5 g magnesium chloride
    • 2.5 g potassium nitrate
    • 0.5 g of ferric chloride
    • 1 liter distilled water
  1. Choose a beaker and then click the correct test tube to fill.
      A = complete solution
      B = solution lacking nitrogen
      C = solution lacking sulfur
      D = tap water
      E = distilled water
  2. Place a germinated seedling in the top of each filled test tube. The roots should be in the solution.
  3. Place the germinated seedlings in sunlight (click on sun) and leave for four weeks (click on day line).
Analysis
Results
  1. Draw a scale diagram of each plant – including its roots - in these labeled test tubes.
  2. Which solution gave the most and which the least vigorous growth? Suggest reasons.
  3. How did growths in tap and distilled water compare? Give reasons.
  4. Why is it important for an arable farmer (one who raises crops) to know the mineral content of the soil?