Erosion Lab
Riley Austin
11/15/2013
Background: Soil erosion is the washing away of soil by the flow of water. This occurs due to
deforestation, over grazing and over farming. In this lab we had to test the effects of soil erosion
against different surfaces of land. Using three empty plastic soda bottles we cut them in half and
put soil, pebbles and grass in each one. We tested the permeability of each bottle by pouring
water at one side of the bottle and letting it flow through and land in a measurement cup. We
then recorded how much soil and water was collected into the measurement cup into our data
table. Also mentioning other factors such as the quality of the water and timing it took to get to
the measuring cup.
Problem: How does grass effect the movement of water in an ecosystem?
Hypothesis: I believe the grass would retain the most water of the three bottles due to the root
structures cause by the grass.
Groups:
Control: Bottle of soil Independent: soil, grass, pebbles dependent: permeability of each bottle
experimental: the grass and pebbles bottles
Materials:
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2 liter bottles, cut in half
Potting soil
Grass seed
Water
Pebbles, gravel or leaf litter
Procedure:
Sowing the seeds
1. Put your soil in an empty litter bottle that has been cut in half.
2. Spread grass seeds throughout the soil.
3. Make sure to water the grass seed every 3-4 days and give it direct sunlight.
Testing the effects
1. When the grass has grown 2-4 inches fill two more empty 2L bottles with soil.
2. Cover one with a top cover of pebbles and leave the other one alone as a control.
3. Line the three bottles up on top of an elevated surface. Place an empty beaker underneath
each bottle.
4. Prepare 4 graduated cylinders with 300 mL of water in each.
5. Have a student start a timer and say “GO.” When the timer says go, all 3 graduated
cylinders should be poured onto the soil bottles.
Erosion Lab
Riley Austin
11/15/2013
6. Record the time, amount, and color of the water discharge in the table below. Then,
answer the questions.
Data:
Bottle
Water collected (mL)
Time for water to
stop flowing (sec)
With Grass
With Groundcover
With soil only
0
0
220
0
0
1:41 sec
Qualitative
Observations (color,
density, etc).
no
no
Black/poor quality
Conclusion questions
1. Describe the difference in the water collected from each of the 3 bottles.
The bottle that consisted of grass and pebbles didn’t have any water flow through
it. The bottle that consisted of only soil did have water flow through it.
2. Using your data to support your answer, after deforestation, what would be most
effective: planting grass seed, leaving rotting material behind, or leaving bare soil?
Support your answer.
I believe that planting grass seeds is the best way to go due to the roots structures
allowing the soil to hold more water which prevents things like run off and soil erosion.
3. Which setting would allow the greatest chance of water filtration (for cleaning pollutants,
etc)? Explain your answer.
The grass would be the greatest chance of water filtration just because they are
able to hold more water in general and help filter out some of the bad pollutants in water.
Since there’s more water being held there’s less run off. Since there is less run off there
less pollutants getting into our drinking water.
4. Describe how this lab could be done on a larger scale to test the effects over a longer
period of time. Give a complete. You could look at larger areas that just have soil, grass
and pebbles and test the permeability of the soil after a rain fall.
Analysis:
What I learned from this experiment is that grass and soil has the greatest water capacity
and soil itself has the greatest permeability. Due to clear cutting and run off issues, we should
solve them by planting grass seeds into the soil so that it can prevent these issues from occurring.
General Analysis:
Erosion Lab
Riley Austin
11/15/2013
According to Reuters.com soil erosion does have an impact on global warming. The
chemicals in the soil being passed through the water runoff and evaporation into the atmosphere,
creating warmer climates and more ocean acidification.
Citation: http://www.reuters.com/article/2012/02/13/us-unep-soil-idUSTRE81C13J20120213
Erosion Lab
Riley Austin
11/15/2013
Erosion Lab
Riley Austin
11/15/2013