Introduction My experiment is a test into which soil retains/absorbs the most water. This idea was prompted by an earlier project this year. It was a very interesting topic and I wanted to continue my research further. It is a pretty simple project, but it has a very important meaning and much in-depth research and hard work. I hope you enjoy my presentation!
Problem Which kind of soil retains the best, when water is poured through it?
Research Permeability is the ability of water to flow through a soil is referred to as the soil's permeability There is 4 types of soil: Clay, Humus, Sand, and Gravel Soil is made up of 4 mail components: Water, Air, Mineral Particles, and Organic Matter. (Organic Matter is made up of 3 main parts: Roots, Humus, and Organisms) Weathering causes layers in soil. There can be up to 5 layers in soil: O, A, B, C, and R horizons Soil texture is based on the size of the particles in the soil. Pore space is the void space between particles of soil Pore space helps determine permeability
Research (C0ntinued) Rocks can also be permeable Permeable rocks are vulnerable to weathering & erosion Clay usually has the least permeability rate because of it’s very little pore spaces Mid to high permeability rates are the best for plant growth Soil with very little pore space is not good for plant growth if the plant roots cannot fit through the pore space Soil with no plant life is susceptible to erosion Sand and clay have the smallest particles. Humus and clay retain water the best usually
Hypothesis If I pour water through four different kinds of soil, thenHumus will retain the most water because Humus has very tiny pore space
Materials 4 Rubbermaid 2 Liter containers 1 roll of GardenPlus burlap Scissors 1 roll of Bounty paper towels 1000 ml of Humus 1000 ml of Clay 1000 ml of Sand 1000 ml of Gravel 2 measuring cups 2000 ml of water 4 Office Depot rubberbands
Procedures 1. Cut four strips of the burlap. 2. Fold the burlap to fit the four 2 Liter containers. 3. Place the burlap on the containers and secure it with a rubber band. 4. Place the containers on a paper towel, incase of spills. 5. Then measure out 1000 ml of sand, humus, clay, and gravel. 6. Carefully, pour the soil on the burlap covered containers. 7. Measure out 2000 ml of water. 8. Pour 500 ml on each soil type. 9. Take the soil and burlap off the containers after the water has stopped dripping. 10. Record the results. 11. Repeat 3 more times.
Variables Controlled Variables- In my experiment I have very many controlled variables:
The amount of water pored through the soil (500 ml)
The amount of soil per container (1000 ml)
The size of the containers (2 Liters)
The amount of burlap used (42 cm. by 30 cm.)
The size of the rubber bands (10 cm.)
Without these variables this would be an inaccurate experiment.
Independent Variable The independent variable (the variable I changed) was the soil. Instead of having one soil I had four soil types. This enhanced my experiment because without the independent variable my experiment would really only be an activity.
Dependent Variable If I change the soil types then the results will differ. This will happen because each soil has a different permeability rate based on the amount of pore space between particles.
Results Humus: 306, 297,301 ml. Clay:456, 432, 466 ml. Sand: 387,341, 352 ml. Gravel: 500,500,500 Ml of water left over Type of Soil
Conclusion Overall the project was a success. I am glad I got a “clear-cut winner”. My hypothesis was correct, Humus retains the most water. Humus retained a full 59 more milliliters of water than the 2nd place sand. This project was very simple and easy and had great results. I think everything in my experiment was to the fullest accuracy level possible. I think I might change the burlap, though it worked it fine, a very fine mesh might be more reliable. I am curious to know if the clay hap been compacted tighter, would it have retained more water. Before doing this project I barely knew what permeability was, or that different soils had different permeability rates. Now I know many facts and examples of permeability.
Conclusion on the results The results were all pretty realistic. The averages on each soil type were: Humus: 301 Clay: 451 Sand: 360 Gravel: 500 Total Average in ml I think the reason gravel did the worst is because it had the largest pore space. With such large pore space it couldn’t absorb any water. I think the opposite happened for the Humus. Types of soil
Bibliography "Managing Soil Tilth: Texture, Structure and Pore Space." Colorado State University Extension. N.p., n.d. Web. 20 Apr. 2011. <http://www.ext.colostate.edu/mg/gardennotes/213.html>. (All the light blue note facts) "ftp://ftp.fao.org/fi/CDrom/FAO." ftp://ftp.fao.org/fi/CDrom/FAO. N.p., n.d. Web. 12 Apr. 2011. <ftp://ftp.fao.org/fi/CDrom/FAO_Training/FAO_Training/General/x6706e/x6706e09.htm >. (All the green note facts) "http://http://cmex.ihmc.us/da." http://http://cmex.ihmc.us/da. N.p., n.d. Web. 12 Apr. 2011. <http://cmex.ihmc.us/data/catalog/AncientGroundwater/poreSpace.html >. (All the Orange note facts)
Closing I hope you enjoyed my project, By: Tommy Hayes