Introduction
The particles that make up soil are categorized into three groups by size – sand, silt, and clay. Particles of clay are the smallest and those of sand the largest. A mix of the three makes up the majority of soils. Soil texture is a function of the proportions of sand, silt, and clay. For instance, sand, slit, and clay are almost equally distributed in a clay loam texture soil. The weathering process is what causes these textural differences.
Task
Students will identify the texture of soil (sand, silt, or clay) by feeling it with their hands.
Students will determine the texture of a soil sample by assessing its ability to form a ball and ribbon under specific moisture conditions.
Process
Feel Test
Gather the following materials.
A small amount of different soil samples (sand, silt, clay)
Water (in a spray bottle or small containers)
Paper towels
A plastic tray or bowl for each student
Step 1: Add a small amount of water to their soil sample. It should be moist, but not soggy. This will help them better feel the texture.
Step 2: Take a small handful of the soil and rub it between their fingers. Focus on how it feels: Is it gritty, smooth, or sticky?
Step 3: Identify the Texture:
Sand: If the soil feels gritty and doesn’t stick together, it is likely sandy soil.
Silt: If the soil feels smooth and soft, it is likely silty soil.
Clay: If the soil feels sticky and smooth, it is likely clay soil.
Step 4: Label the texture of each soil sample based on their observations.
Ball and Ribbon Test
Materials Needed:
A small amount of soil sample
Water
Your hands
Ruler
Step 1: Collect a small amount of soil.
Step 2: Add water to the soil and mix it until it’s damp but not too wet.
Step 3: Take the moist soil and roll it in your hands to form a ball.
Pay attention to how the soil feels when rolling it into a ball:
Sandy soil: The ball will fall apart easily.
Clayey soil: The ball will stay together firmly.
Loamy soil: The ball will hold together, but it may break slightly when squeezed.
Step 4: Once you’ve formed the ball, squeeze it between your thumb and forefinger to create a ribbon. Try to slowly pull the soil apart while pressing your thumb on the top and forefinger on the bottom.
Sandy soil: It will not form a ribbon, or it will be very short and crumble easily.
Loamy soil: The ribbon will be short (1–2 inches) and break easily.
Clayey soil: The ribbon will be long, smooth, and may not break easily.
Step 5: Measure the soil using the ruler.
Step 6: Determine the type of soil based on the result.
A video taken from https://www.youtube.com/watch?v=GWZwbVJCNec&t=39s will give visual instruction on how to conduct a ribbon test.
Evaluation
- Evaluate students based on their ability to correctly identify and classify the soil types.
- Check their recorded observations to see if they include accurate descriptions that match the expected characteristics of each soil type.
- After performing the ball and ribbon tests, students should be asked to classify the soil sample they tested based on their observations. Write a short report summarizing their experiment and explaining how the ball and ribbon tests helped them determine the soil texture.
Conclusion
Plant growth, water retention, and erosion are all directly impacted by soil texture. Sandy soil may not hold enough water or nutrients for plants because it drains quickly. Although it can be prone to compaction, silt offers a good balance between water retention and nutrient availability. Although clay soil is good at retaining water and nutrients, it can get soggy and make it difficult for roots to grow. Gardeners, farmers, and land managers can make better decisions regarding soil management, irrigation, and erosion control by having a better understanding of the properties of various soil textures.
Credits
McGrath, E. R. (2015). Determining Soil Texture by Feel. Retrieved from UKnowledge: https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1139&context=anr…
Soil Basics. (n.d.). Retrieved from Soil Science Society of America: https://www.soils.org/about-soils/basics/
Teacher Page
The objective of this activity is to help students identify and classify soil texture (sand, silt, clay, and loam) through a hands-on "feel test." In order to determine the relative amounts of sand, silt, and clay in the soil, students will use their sense of touch to explore the physical characteristics of various soil samples. The purpose of this activity is to increase their understanding of how environmental factors and plant growth are impacted by soil texture.