Title: Nutrient Runoff Experiment

Overview

In Kansas, most of the runoff that drains into rivers and streams comes from agricultural land. Cropland and pastures generally contain large amounts of fertilizers and manure, as well as harmful pesticides and herbicides.

Stormwater runoff is called non-point source pollution and includes water that runs over lawns, driveways, agricultural fields, and roads during a rainstorm. This runoff does not get treated in water-treatment plants, instead running untreated into rivers and streams. In the US, non-point source pollutants are the most difficult to control and are the leading cause of water pollution.

In contrast, point source pollutants are those that drain into a river from a location such as a pipe or a ditch. These carry water from businesses, residencies, factories, power plants, sewage treatment plants, and combined stormwater and sewage outfalls.

Phosphorous is a nutrient that is found naturally in water bodies. It forms the building blocks for important biological processes in all aquatic organisms. When nutrients like phosphorous rise to abnormally high levels, the balance of the water ecosystem is disturbed. For example, when high levels of nutrients such as nitrogen and phosphorous are carried by stormwater runoff to a water body, organisms such as green algae take these nutrients and grow out of proportion. When the algae decay, they use oxygen available in the water and animals such as fishes that use oxygen to breathe die. We can also be affected by high nutrients since traces of a chemical produced by algae called geosmin may remain present in the water even after it is treated and make our drinking water taste or smell earthy or musty.

Pollution from stormwater runoff can be reduced in two ways. First, when you apply fertilizers to agricultural fields or lawns, be careful not to apply more than is needed. Second, avoid applying fertilizer right before a storm. When fertilizer is applied before a storm, plants do not have time to use it and the fertilizer left in the soil can be washed off with the rain. When this happens the phosphorous level in the water increases. Being careful about the way fertilizers are applied to agricultural land and residential lawns could greatly reduce the nutrient input to streams, rivers and lakes.

Grades: High School

Learning Objective

To demonstrate the effects of being careless when applying fertilizer to agricultural land and/or residential lawns. 

Kansas Grade Level Expectations – Standards/Benchmarks 

Indicators: 

1. identify the various uses of soil and water in Kansas. 

2. identify the risks and benefits that agriculture, petroleum production, manufacturing, energy production, human communities, and other economic development activities can have on soil and water in Kansas. 

3. describe the problems that Kansans face in regard to solid and hazardous waste disposal. 

4. describe the problems that Kansans face in regard to urban growth. 

5. identify the reasons that acquisition of private land for public use is an issue in Kansas. List the arguments for all sides of the issue. 

Indicators: 

1. connect questions with appropriate means of inquiry, including scientific investigations, historical inquiry, and social science observation and research. 

2. use sampling techniques. 

3. apply observation and measurement skills in field situations. 

4. gather information from a variety of sources. 

5. create models and simulations. 

6. differentiate between causes and effects and identify when causality is uncertain.

Materials:

• Standard metal paint tray 
• Standard metal paint tray liners 
• Fine door mesh 
• Sod 
• Osmocote fertilizer

NOTE: Try not using any product that turns water a different color. For example, Miracle Grow turns the water blue, which interferes with the phosphate test results.

• Hammer, glass bottle or rolling pin
• Aluminum foil 
• Exacto knife and scissors 
• Measuring cup 
• Phosphorous test kit (CHEMets phosphate testing kit: sample cup with lid, A-8500 activator solution, ampoule, comparison tubes, and comparator tube for low concentrations) 
• pH test strips 
• Goggles
• Measuring tape
• Turkey baster
• Watering can
• 1 tile
• ~5mls of car or mowing machine oil
• Timer

Standard Metal Paint Tray	Standard Metal Paint Tray Liners	Fine Mesh	Sod
Hammer and Foil	Measuring Cup	pH and Nitrogen Test*	Phosphorous Test*

*NOTE: To order a phosphorous and pH test click here

Method:

1-Use the scissors to cut a piece of mesh that covers the inside area of the tray liners. 
2-Bend approximately 3 inches of one side of the mesh.

3-Place the liner on the metal paint tray .

4-Place the mesh piece on the liner with the bend end towards the bottom part of the tray (the part that is not raised- where the paint would collect). 

5-Fold the surrounding upper part of the mesh around the raised part of the set up.

 

6-Turn the sod so that the soil and roots are facing upwards. Use the measuring tape to measure a 6”x10” piece. Safely use the exacto knife to cut the piece, this process might require you to run the knife several times through the same cut before the piece of sod is released.

NOTE: To maintain the remaining sod in good state, place in a site where no significant amount of grass grows and water it every day. If you are keeping the sod for a significant period, it may damage the grass underneath it. If it is not possible to place the sod in this type of area, place on a piece of plastic and water regularly.

7-Place the 6”x10” piece of sod on the mesh, making sure that one of the pad’s sides rests against the bent side of the mesh.

8-Cut an ~8”x10” piece of aluminum foil and fold it in half two times

9-Place 3 fertilizer pellets inside the foil “booklet” and crush the pellets with a hammer until you obtain a fine powder

NOTE: It is necessary to crush the pellets since Osmocote is time-released and we desire the fertilizer to be readily available

10-Sprinkle the fertilizer on top of the piece of sod making sure to cover evenly the whole area

 

 

Measure 2 cups of tap water and pour it on the piece of sod making sure to cover the whole area. Wait 2-3 minutes.

NOTE: Small pieces of soil will come out with the water; bigger pieces will be trapped by the mesh.

Use the turkey baster to collect the water from the bottom of the tray. Try avoiding large amounts of soil that filtered through the mesh. Transfer it to the measuring cup and compare this quantity to the initial quantity (2 cups). The difference between these two quantities is the amount of water that was absorbed by the piece of sod. 

Wait 2-3 minutes and conduct the phosphorous and pH test. Nutrient levels will be high simulating what would happen if fertilizer was applied right before a storm

 

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Now see what happens after the grass has time to absorb the fertilizer before it "rains"

Repeat steps 1-10 using a new liner and new grass and wait 1-2 hours until you add water (repeat step 11) 

Use the turkey baster to collect the water from the bottom of the tray. Transfer it to the measuring cup and compare this quantity to the initial quantity (2 cups). The difference between these two quantities is the amount of water that was absorbed by the piece of sod. 

Conduct the phosphorous and pH tests again. Test whether the nutrient levels are higher or lower in comparison to the first trial. Did the grass absorb the fertilizer? Do you think there will be more or less of it available to runoff during a storm?

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Effects of runoff on pavement:

To demonstrate the effects of runoff on pavement, use a new liner and place a ceramic floor tile upside down where the piece of sod would go.  

Drip ~5 ml of motor oil on the upper part of the tile. 

Wait 2-3 minutes and apply 2 cups of tap water with a watering can to the tile .

Use the turkey baster to collect the water from the bottom of the tray.

Transfer it to the measuring cup and compare this quantity to the initial quantity (2 cups).

The difference between these two quantities is the amount of water that was absorbed by the concrete .

Obtain a new tile and place it upside down on a new liner. 

Drip ~5 mls of motor oil on the upper part of the tile. 

Wait 1-2 hours and apply 2 cups of tap water with a watering can to the tile. 

Use the turkey baster to collect the water on the bottom of the tray.

Transfer it to the measuring cup and compare this quantity to the initial quantity (2 cups).

The difference between these two quantities is the amount of water that was absorbed by the concrete.

NOTE: The difference between the water absorbed and the initial quantity of water applied (2 cups) should NOT differ significantly because the tile is a non-permeable surface