Erosion Lab

 

Collaborator: Habiba Fofana

Introduction: Erosion is the gradual destruction of something. There are four causes of erosion. Water, wind, humans, and glacial. Moving water is a major agent in erosion. Soil erosion is one form of soil degradation along with soil compaction, low organic matter, loss of soil structure, poor internal drainage, salinization, and soil acidity problems. These other forms of soil degradation, which are also very serious, usually contribute to accelerated soil erosion. Soil erosion is a naturally occurring process on all land. A important agent of soil erosion, water, contributes a significant amount of soil loss each year. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an unnatural rate causing serious loss of topsoil. The loss of soil from farmland can be seen in reduced crop production potential, lower surface water quality and damaged drainage networks. Sand, sandy loam and loam textured soils tend to be less erodible than silt, very fine sand, and certain clay textured soils. 

Problem: How does grass and other ecosystem environments effect the movement of water in an ecosystem?

Hypothesis:

1. If grass is used as the pseudo- environment for an ecosystem, then water will move through it in 30 sec.

2. If mulch is used as the pseudo-environment for an ecosystem , then water will move through it in 20 sec.

3. If rocks are used as the pesudo-environment for an ecosystem, then water will move through it in 10 sec.

 

Parts of the Experiment:

Control group: Grass

Experimental group: Mulch and rocks

Independent variable: Grass, mulch, rocks

Dependent Variable: How long it took.

Controlled Variables: How much water was poured in

 

Materials:

-2 liter bottles, cut in half

-Potting soil

-Grass seed

-Water

-Mulch

-Rocks

 

Procedures:

Sowing the seeds

• Place soil in an empty 2L bottle that has been cut in half (see picture above).  Spread grass seed evenly throughout the soil.

• Water grass seed every 3-4 days and allow it to sit near a source of sunlight or under a plant grow lamp.

Testing the effect

• When the grass has grown 2-4 inches in height, you are ready to test the effects.

• Fill two more empty 2L bottles with soil.  Cover one with a top cover of your choice (gravel, pebbles, or leaf litter) and leave the other one alone as a control.

• Line the three bottles up on top of an elevated surface.  Place an empty beaker underneath the mouth of each bottle.

• Prepare 4 graduated cylinders with 100 mL of water in each.

• 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.

• Record the time, amount, and color of the water discharge in the table below.  Then, answer the questions.

 

Data:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Data Analysis: 

For each variable, 200ml of water was poured in. We tested grass and rocks first. The bottles they were in were sitting on bins and they were propped up by a marker. The water in the grass and rocks stopped flowing out at 23 seconds. Almost 100ml of water had poured out of the rocks, but only .5ml had poured out of the grass. We then tested the mulch. We thought the experiment would go better if we supplemented the marker with a glue bottle. The water poured into the mulch stopped flowing out at 24 seconds and only 25ml had poured out. This means that the grass had subsequently absorbed nearly 195ml of water, the rocks had absorbed half and that the mulch had absorbed 175ml of the water that was poured in.

 

 

Conclusion:

The hypothesis stated that water would flow through the grass in 30 seconds, the mulch in 20 seconds and the rocks in just 10 seconds. The hypothesis was incorrect. Due to human error, the bottle was not propped up enough, so the water in the grass and rocks stopped flowing out at the same time, 23 seconds. The mulch experiment was not rectified completely, so the water in the mulch stopped flowing out prematurely too, at 24 seconds. The runoff of all three variables looked to be about the same: dirty and brown. This might be caused because of the conditon of the water that was used to conduct the experiment. Rocks allowed the most water to pass though, so in the real world; rocks would be detrimental to farming. Rocks would increase the rate of water flow, therefore increasing the level of soil erosion. Soil loss seems to be of grave significance when pertaining to the fields of agriculture. If a farmer wanted to decrease his annual amount of soil loss due to erosion caused by water; he shoud invest in stopping it with grass or something akin to the thick soil that accompanies the growth of grass. If someone working in the field of agriculture has experienced deforestation, their best solution would be to plant grass seeds because that would absorb most of the water that would pass through. If one wanted to test this on a bigger scale, they would have to position all three variables each in front of a patch of crops that are growing, and control how much water goes through. Then we could see the effects in real time.

 

Citations:

"Soil Erosion: Causes and Effects." Soil Erosion Causes and Effects: (n.d.): n. pag. Envirothon. Web. 6 Nov. 2014.

 

"Solving Drainage and Erosion Problems: A Guide for Homeowners - Fairfax County, Virginia." Solving Drainage and Erosion Problems: A Guide for Homeowners - Fairfax County, Virginia. N.p., n.d. Web. 08 Nov. 2014.