Soil Lab
Materials Materials for this lab are:
Spray Bottles
3 Plastic Cups
Rulers
Wax Marker
Soil Analysis Card
Bag of Sand
Bag of Clay
Soil Sample
Tap Water
4 Plastic Cylinders
4 Plastic Vials
4 Plastic Cups
Cheesecloth
Rubber Bands
60cc plastic medicine cups
humus
scissors
balance
Clock with Second Hand
Twist Ties
Variables:
· Independent Variable: The soil used in the various tests.
· Dependent Variable: The composition, pH, and the permeability of the different types of soil.
· Controlled Variable: pH strip used, set up for permeability test
· Control: Topsoil & Sand
· Experimental: The soil collected
Pre-lab Questions 1. Define the following:
a. Porosity: The space for air or liquid within a soil
b. Permeability: Ability of water to flow through a substance
c. Water holding capacity: Ability of the soil to hold water (inversely related to porosity)
d. Solution: Molecules dissolved in a solvent
e. Suspension: Particles transported in water
2. What industries would find it important to know the structure of the soil? Construction and Agriculture
3. Using what you know about North Carolina now, would large scale use of septic tanks work well? For the most part no
Procedure Determining Soil Texture
1. You will be assigned a specific soil to test. Put samples of clay, sand and your soil into cups and take them to your workstation. Fill a spray bottle with tap water. Follow the directions to classify the type of soil you have.
Determination of Permeability
1. Suspend the wet columns about 1 inch above a graduated cylinder.
2. Put 50mL of water into a cup. Designate one member as the timekeeper and one as the recorder. When everyone is ready, pour the water onto the wet sand. The timer should time how long it takes until the first drop of water comes out of the bottom of the column. Set up a data table to record this information. Watch the column until there is not more water standing above the sand and no more dripping through the column. Record this time as well.
3. Repeat with the remaining wet columns. If the percolation through the column is slow, record the start time and set up another column. You will have to keep an eye on the slow columns so that you won’t miss the first drop of the final one.
4. As you finish with a column clean out the column and prepare fresh columns of sand , clay, humus, and soil as in the previous portion. Repeat the procedure with each of the fresh columns.
5. Record all times.
Data Table Problem: Which type of soil will have the greatest permeability?
Hypothesis: Pebbles because they don't really stick together as well as other soils.
Data table:
Spray Bottles
3 Plastic Cups
Rulers
Wax Marker
Soil Analysis Card
Bag of Sand
Bag of Clay
Soil Sample
Tap Water
4 Plastic Cylinders
4 Plastic Vials
4 Plastic Cups
Cheesecloth
Rubber Bands
60cc plastic medicine cups
humus
scissors
balance
Clock with Second Hand
Twist Ties
Variables:
· Independent Variable: The soil used in the various tests.
· Dependent Variable: The composition, pH, and the permeability of the different types of soil.
· Controlled Variable: pH strip used, set up for permeability test
· Control: Topsoil & Sand
· Experimental: The soil collected
Pre-lab Questions 1. Define the following:
a. Porosity: The space for air or liquid within a soil
b. Permeability: Ability of water to flow through a substance
c. Water holding capacity: Ability of the soil to hold water (inversely related to porosity)
d. Solution: Molecules dissolved in a solvent
e. Suspension: Particles transported in water
2. What industries would find it important to know the structure of the soil? Construction and Agriculture
3. Using what you know about North Carolina now, would large scale use of septic tanks work well? For the most part no
Procedure Determining Soil Texture
1. You will be assigned a specific soil to test. Put samples of clay, sand and your soil into cups and take them to your workstation. Fill a spray bottle with tap water. Follow the directions to classify the type of soil you have.
Determination of Permeability
1. Suspend the wet columns about 1 inch above a graduated cylinder.
2. Put 50mL of water into a cup. Designate one member as the timekeeper and one as the recorder. When everyone is ready, pour the water onto the wet sand. The timer should time how long it takes until the first drop of water comes out of the bottom of the column. Set up a data table to record this information. Watch the column until there is not more water standing above the sand and no more dripping through the column. Record this time as well.
3. Repeat with the remaining wet columns. If the percolation through the column is slow, record the start time and set up another column. You will have to keep an eye on the slow columns so that you won’t miss the first drop of the final one.
4. As you finish with a column clean out the column and prepare fresh columns of sand , clay, humus, and soil as in the previous portion. Repeat the procedure with each of the fresh columns.
5. Record all times.
Data Table Problem: Which type of soil will have the greatest permeability?
Hypothesis: Pebbles because they don't really stick together as well as other soils.
Data table:
Questions 1. The break down of the parts of your soil is shown in the soil triangle. Use the soil triangle to decide what type of soil the following are.
- 10% Clay, 60% Sand, and 30% Silt: Sandy Loam
- 60% Clay, 20% Sand, and 20% Silt: Clay
- 20% Clay, 20% Sand, and 60% Silt: Silt Loam
- 20% Clay, 40% Sand, and 40% Silt: Loam
2. Considering all the samples analyzed by your class in the first three parts, do you find any relationship between texture and consistence? Yes. Sandy soil is a very grainy texture and it doesn't mold when dampened. Clay has plastic like texture that gets very sticky and is easily molded when dampened. Silt has a much smoother texture than sand, but retains some of clay's characteristics in its ability to mold.
3. How might the consistence of soil affect the growth of plants? Think about wet and dry conditions. The consistence of soil affects the growth of plants by determining how much moisture is able to reach the plants roots. Soil that has a consistency of primarily clay and will not be able to distribute an adequate amount of water to the plant. Clay has a very high water holding capacity and an extremely slow permeability, this signifies that the water would get absorbed in the clay and never reach the roots of the plant, thus not allowing it to grow. Sand and silt are much better suited to growing plants as more water can flow through the soil at a faster rate reaching the roots. In dry conditions, it is even more crucial for plants to receive adequate water. The consistency needs to be able to supply the plant with water by having an acceptable permeability.
4. Observe the other groups results for the water holding capacity. Was the capacity the same for all the soil sampled? No. The water holding capacity of the clay was by far the largest. It only allowed 7 out of the fifty milliliters that was poured into the soil to escape. The sand had the second largest, allowing 19 mL of the total 50 mL to be released. The topsoil had the least water holding capacity and the water very quickly flowed through the soil releasing 26 mL.
5. What characteristic of soil is most important in determining water holding capacity? The composition of the soil is the most important in determining the water holding capacity. Clay generally has a much higher water holding capacity than that of silt or sand because the particle size of the clay is much smaller allowing much less water to escape. Sand, in comparison, has very large particles which creates space that the water very easily flows out of.
6. Imagine a sloping field of very sandy soil and a sloping field of soil with a very high clay content, each with an identical drainage ditch at the bottom. In a prolonged heavy downpour, do you think one ditch will be more likely to flood then the other? Why? I think the sandy soil would be much less likely to flood than the clay soil. This is primarily because of the sandy soil’s permeability. Water flows much faster through sandy soil than it does through clay soil. The water would flow into the sandy soil and into the earth, thus, flooding more slowly. The clay soil would accumulate water much faster as the water would take much longer to flow through the soil.
7. If you have two fields of crops, one in which the soil was mostly sand and the other mostly clay, which would you have to water most often and why? You would have to water the sandy soil most often. The sandy soil has a much lower water holding capacity than the clay soil. The sandy soil, therefore, wouldn’t hold as much water than the clay soil would so you’d need to water the clay soil more often to be sure the plants get a sufficient amount of water. This isn’t as much of a problem in the clay soil because the clay naturally holds more water.
8. Use the information you have collected about the local soil samples and suggest how this would affect agriculture and building in the area.
Based on the information, the local soil in the area is primarily clay based. Agriculture has both positives and negatives to having clay soil. The primary positive to having clay soil is that it holds moisture very well; however, the nature of clay makes roots very hard to grow and also causes very slow draining. The soil is also very slow to rise in temperature in the spring. Building a foundation on the soil has both its positives and negatives as well. An advantage is that it is relatively cheap compared to other common foundation material; however, water leakage and damage as well as pressure buildups are common issues that can plague construction.
Conclusion
My hypothesis was correct. Pebbles had the highest permeability since they don't bind together as other soils do.
This experiment’s results were pretty accurate. However, a source of error that i found was the test to determine the soil’s composition. The chart was not as descriptive as it could have been, which, in return, made determining the composition easy to commit a mistake and come to the wrong conclusion about the soil composition. This was also the only test to determine soil composition so the composition may not be entirely accurate. When recording the permeability, only one trial was done. Having multiple trials and taking an average would have ensured the lab in giving a more accurate permeability result.
This lab has many applications to the real world,mainly in agriculture and construction. Knowing the soil composition of the ground allows agriculture to be more successful. This lab proved that certain soil compositions retain more water than others, for example, clay retains much more water than sandy soil. This is helpful to the fact of knowing how much water to give a plant because of the soil it is in. Being able to know the soil’s composition allows the agriculture industry and home gardeners to grow plants at a higher success rate. Knowing the soil is also crucial in construction. Construction companies rely on knowing what type of soil they are building on as it could mean the difference between a safe and an unsafe building.
- 10% Clay, 60% Sand, and 30% Silt: Sandy Loam
- 60% Clay, 20% Sand, and 20% Silt: Clay
- 20% Clay, 20% Sand, and 60% Silt: Silt Loam
- 20% Clay, 40% Sand, and 40% Silt: Loam
2. Considering all the samples analyzed by your class in the first three parts, do you find any relationship between texture and consistence? Yes. Sandy soil is a very grainy texture and it doesn't mold when dampened. Clay has plastic like texture that gets very sticky and is easily molded when dampened. Silt has a much smoother texture than sand, but retains some of clay's characteristics in its ability to mold.
3. How might the consistence of soil affect the growth of plants? Think about wet and dry conditions. The consistence of soil affects the growth of plants by determining how much moisture is able to reach the plants roots. Soil that has a consistency of primarily clay and will not be able to distribute an adequate amount of water to the plant. Clay has a very high water holding capacity and an extremely slow permeability, this signifies that the water would get absorbed in the clay and never reach the roots of the plant, thus not allowing it to grow. Sand and silt are much better suited to growing plants as more water can flow through the soil at a faster rate reaching the roots. In dry conditions, it is even more crucial for plants to receive adequate water. The consistency needs to be able to supply the plant with water by having an acceptable permeability.
4. Observe the other groups results for the water holding capacity. Was the capacity the same for all the soil sampled? No. The water holding capacity of the clay was by far the largest. It only allowed 7 out of the fifty milliliters that was poured into the soil to escape. The sand had the second largest, allowing 19 mL of the total 50 mL to be released. The topsoil had the least water holding capacity and the water very quickly flowed through the soil releasing 26 mL.
5. What characteristic of soil is most important in determining water holding capacity? The composition of the soil is the most important in determining the water holding capacity. Clay generally has a much higher water holding capacity than that of silt or sand because the particle size of the clay is much smaller allowing much less water to escape. Sand, in comparison, has very large particles which creates space that the water very easily flows out of.
6. Imagine a sloping field of very sandy soil and a sloping field of soil with a very high clay content, each with an identical drainage ditch at the bottom. In a prolonged heavy downpour, do you think one ditch will be more likely to flood then the other? Why? I think the sandy soil would be much less likely to flood than the clay soil. This is primarily because of the sandy soil’s permeability. Water flows much faster through sandy soil than it does through clay soil. The water would flow into the sandy soil and into the earth, thus, flooding more slowly. The clay soil would accumulate water much faster as the water would take much longer to flow through the soil.
7. If you have two fields of crops, one in which the soil was mostly sand and the other mostly clay, which would you have to water most often and why? You would have to water the sandy soil most often. The sandy soil has a much lower water holding capacity than the clay soil. The sandy soil, therefore, wouldn’t hold as much water than the clay soil would so you’d need to water the clay soil more often to be sure the plants get a sufficient amount of water. This isn’t as much of a problem in the clay soil because the clay naturally holds more water.
8. Use the information you have collected about the local soil samples and suggest how this would affect agriculture and building in the area.
Based on the information, the local soil in the area is primarily clay based. Agriculture has both positives and negatives to having clay soil. The primary positive to having clay soil is that it holds moisture very well; however, the nature of clay makes roots very hard to grow and also causes very slow draining. The soil is also very slow to rise in temperature in the spring. Building a foundation on the soil has both its positives and negatives as well. An advantage is that it is relatively cheap compared to other common foundation material; however, water leakage and damage as well as pressure buildups are common issues that can plague construction.
Conclusion
My hypothesis was correct. Pebbles had the highest permeability since they don't bind together as other soils do.
This experiment’s results were pretty accurate. However, a source of error that i found was the test to determine the soil’s composition. The chart was not as descriptive as it could have been, which, in return, made determining the composition easy to commit a mistake and come to the wrong conclusion about the soil composition. This was also the only test to determine soil composition so the composition may not be entirely accurate. When recording the permeability, only one trial was done. Having multiple trials and taking an average would have ensured the lab in giving a more accurate permeability result.
This lab has many applications to the real world,mainly in agriculture and construction. Knowing the soil composition of the ground allows agriculture to be more successful. This lab proved that certain soil compositions retain more water than others, for example, clay retains much more water than sandy soil. This is helpful to the fact of knowing how much water to give a plant because of the soil it is in. Being able to know the soil’s composition allows the agriculture industry and home gardeners to grow plants at a higher success rate. Knowing the soil is also crucial in construction. Construction companies rely on knowing what type of soil they are building on as it could mean the difference between a safe and an unsafe building.