Erosion Lab
Collaborators:
Melissa Daria
Tor Ruddy
Wisam Salah
Enny Dlaleye
Samantha Maldonado
Austin Dowler
Laura Sales
Seth Newberry
Introduction:
Plant life, and their roots, have been proven to limit soil erosion in ecosystems. In the Hubber Brook experiment, conducted by Hubbard Bormann in 1971, the loss of water and nutrients from uncut forests were compared to that of stripped forest. The results concluded that deforestation increased the level of overall erosion and nutrient loss in the forests, as well as increased water turbidity in downhill streams. It also stressed the importance of riparian areas, which are defined as the ecosystems along bodies of water such as streams. These riparian areas have been proven to be crucial in maintaining stream and forest health. The goal of our lab was to model a similar experiment in the class room, in order to judge whether or not the presence of grass in soil would delimit the amount of soil erosion caused by water. These findings could be easily applied to both environmental inquiries on deforestation as well as simply understanding lawn health.
Problem: How does the growth of grass affect erosion caused by water?
Hypothesis: If there is more grass present in the environment, then there would be less soil erosion by water.
Parts of experiments:
Control: Sample 1 (soil with no grass)
Experimental: Sample 2 (soil with grass)
Dependent: Soil erosion
Independent: Plant growth present
Materials:
Methods:
Data:
Melissa Daria
Tor Ruddy
Wisam Salah
Enny Dlaleye
Samantha Maldonado
Austin Dowler
Laura Sales
Seth Newberry
Introduction:
Plant life, and their roots, have been proven to limit soil erosion in ecosystems. In the Hubber Brook experiment, conducted by Hubbard Bormann in 1971, the loss of water and nutrients from uncut forests were compared to that of stripped forest. The results concluded that deforestation increased the level of overall erosion and nutrient loss in the forests, as well as increased water turbidity in downhill streams. It also stressed the importance of riparian areas, which are defined as the ecosystems along bodies of water such as streams. These riparian areas have been proven to be crucial in maintaining stream and forest health. The goal of our lab was to model a similar experiment in the class room, in order to judge whether or not the presence of grass in soil would delimit the amount of soil erosion caused by water. These findings could be easily applied to both environmental inquiries on deforestation as well as simply understanding lawn health.
Problem: How does the growth of grass affect erosion caused by water?
Hypothesis: If there is more grass present in the environment, then there would be less soil erosion by water.
Parts of experiments:
Control: Sample 1 (soil with no grass)
Experimental: Sample 2 (soil with grass)
Dependent: Soil erosion
Independent: Plant growth present
Materials:
- 2 empty beakers
- 4 filled beakers (200 mL) of water
- 2 samples in emptied litre bottles - Sample A: Soil
- - Sample B: Soil with grass grown
- Counter/table with viable inclined surface
Methods:
- Place the two samples at even inclines on an available surface. Ensure that the bottom of the bottle is tilted upwards, and the nozzle is at a lower incline. Place the two empty beakers under the two nozzles.
- Pour 200 mL of water into each sample, pouring from the bottom of the bottle, so the water runs downward towards the nozzle.
- Observe the contents of the empty beakers below the nozzles.
Data:
Data Analysis:
Following the experiment, several factors were observed, some of which were unexpected prior to the lab. The contents of the beaker under sample A, which contained only soil, consisted of 40 ml of water. This was out of the 200 mL poured in. Additionally, we observed the overall water quality, and described it as having moderate turbidity. There were large particles of mulch and debris, as well as some contents of loam. Sample B's beaker, in contrast, contained 55 mL of the original 200 mL. The water quality was observed as having high turbidity, with a large loam content on top of, and suspended in the water. Sample B contained the grass of the two samples. These findings lead us to question our hypothesis, as the data presented that sample A, without grass, experienced less soil erosion.
Conclusion:
Our lab's findings were contrary to our group's original hypothesis, which stated that if there is more grass present in the environment, then there would be less soil erosion by water. Rather than there being less erosion in sample B containing grass, there appeared more soil in the water runoff than that of sample A, without grass. It would then lead us to conclude that the absence of grass leads to less erosion. However, we know from the Hubbard Brook experiments, and generally accepted environmental theories, that this statement is false. Therefore several questions, as well as problems with the lab, were raised following the experiment. For example, water was poured directly from the top of the samples, which did not accurately simulate rain, which would have been evenly dirstubuted throughout the environment and may have been a factor in the problematic results of the experiment. Another such problem was the different soils of the two samples. The sample (A) containing the grass had far more loam than that of the more mulch-heavy sample A. Not only would this explain why the grass grew in sample B and failed to germinate in A, but it would also suggest that the more loose, loamy soil was more easily eroded by the water, despite the presence of the grass. In addition, the topic of riparian areas was brought up when the group observed that although there was plenty of grass present in the sample, the area near the end of the bottle (which would simulate a downhill stream outlet) lacked grass. In the environment, when this area by the stream, or riparian area, lacks its plant life, we know that runoff increases dramatically and pollutes the stream with the soil and its nutrients. This would further explain the higher turbidity of sample B. Given more time in the class, this lab would work better when more grass is cultivated evenly throughout the sample, and the soil contents of the samples is more consistent.
Citations
National Management Measures to Protect and Restore Wetlands and Riparian Areas for the Abatement of Nonpoint Source Pollution. N.p.: EPA, July 2005. PDF.
"Hubbard Brook." Hubbard Brook. National Science Foundation, n.d. Web. 20 Mar. 2015.
Following the experiment, several factors were observed, some of which were unexpected prior to the lab. The contents of the beaker under sample A, which contained only soil, consisted of 40 ml of water. This was out of the 200 mL poured in. Additionally, we observed the overall water quality, and described it as having moderate turbidity. There were large particles of mulch and debris, as well as some contents of loam. Sample B's beaker, in contrast, contained 55 mL of the original 200 mL. The water quality was observed as having high turbidity, with a large loam content on top of, and suspended in the water. Sample B contained the grass of the two samples. These findings lead us to question our hypothesis, as the data presented that sample A, without grass, experienced less soil erosion.
Conclusion:
Our lab's findings were contrary to our group's original hypothesis, which stated that if there is more grass present in the environment, then there would be less soil erosion by water. Rather than there being less erosion in sample B containing grass, there appeared more soil in the water runoff than that of sample A, without grass. It would then lead us to conclude that the absence of grass leads to less erosion. However, we know from the Hubbard Brook experiments, and generally accepted environmental theories, that this statement is false. Therefore several questions, as well as problems with the lab, were raised following the experiment. For example, water was poured directly from the top of the samples, which did not accurately simulate rain, which would have been evenly dirstubuted throughout the environment and may have been a factor in the problematic results of the experiment. Another such problem was the different soils of the two samples. The sample (A) containing the grass had far more loam than that of the more mulch-heavy sample A. Not only would this explain why the grass grew in sample B and failed to germinate in A, but it would also suggest that the more loose, loamy soil was more easily eroded by the water, despite the presence of the grass. In addition, the topic of riparian areas was brought up when the group observed that although there was plenty of grass present in the sample, the area near the end of the bottle (which would simulate a downhill stream outlet) lacked grass. In the environment, when this area by the stream, or riparian area, lacks its plant life, we know that runoff increases dramatically and pollutes the stream with the soil and its nutrients. This would further explain the higher turbidity of sample B. Given more time in the class, this lab would work better when more grass is cultivated evenly throughout the sample, and the soil contents of the samples is more consistent.
Citations
National Management Measures to Protect and Restore Wetlands and Riparian Areas for the Abatement of Nonpoint Source Pollution. N.p.: EPA, July 2005. PDF.
"Hubbard Brook." Hubbard Brook. National Science Foundation, n.d. Web. 20 Mar. 2015.