Lecture on Soil Texture

Introduction

• Discussing soil texture and a simple hand test to determine it.
• Soil texture is determined by the ratio of three particle sizes:
  • Sand: Large particles
  • Silt: Smaller particles
  • Clay: Tiny particles
• Texture affects physical traits, particularly water retention.

Water Retention & Soil Types

• Sand: Doesn't hold water well.
• Loam: Holds water well, ideal for plants.
• Clay: Holds a lot of water, sometimes too much for plant availability.

Simple Soil Texture Test

• Tests can be done at home to determine soil texture.

Testing Procedure:

1. Sand Test:

   • Collect a soil sample (e.g., from a desert).
   • Add water; if it runs through quickly, it's sandy.
   • Attempt to roll into a ball: if it crumbles, it's sand.
   • Conclusion: Pure sand will not form a ball.

2. Garden Soil Test:

   • Collect a garden soil sample (e.g., tomatoes garden).
   • Add water, attempt to make a ball: if a ball forms, it's not pure sand.
   • Ribbon Test:
     • Roll the ball between fingers to form a ribbon.
     • If the ribbon is less than 2.5 cm, it's loamy sand or sandy loam.
   • Conclusion: Sample likely sandy loam.

3. Clay Test:

   • Collect another sample suspected to be clay-rich.
   • Add water, notice stickiness (more than previous samples).
   • Forms a ball easily.
   • Ribbon Test:
     • Form a ribbon over 5 cm: classified as clay.
   • Texture Feel Test:
     • If coarse, the sample is a sandy clay.
   • Conclusion: Sample identified as sandy clay.

Summary

• Three different soil textures discussed:
  1. Sand
  2. Sandy Loam
  3. Sandy Clay
• Encouragement to practice soil texture tests at home.
• Future class activities to expand on this.

Questions

• Open invitation for questions on soil texture and testing methods.