Tutorial

Step #1: Gather Materials

The first step of every good experiment is collecting the necessary materials. Most of the supplies required for the Soil Science Lab project can be found in your home or at your local dollar store. If you need help finding any of the materials, check our Bill of Materials for links to other vendors.

Step #2: Collect Soil

Find a location outside to capture your soil sample. This can be in your backyard, your school field, a park, or any other spot with a nice patch of dirt. Make sure to record the coordinates and environmental conditions of your collection site in a notebook or directly into our database entry form. Take pictures to document your experiment for future reference (and for fun!).

1. Locate a spot to collect a soil sample
2. Record the coordinates (latitude and longitude) of your location. Use Google Maps or a similar tool to find this information.
3. Collect a soil sample approximately 6 inches deep and about 0.5 kilograms (~1 lb)
4. Store the soil sample in a container to transport back to your home or school lab
5. Record the following information in your lab notebook or in our database
• Weather conditions
• Humidity levels
• Date and time of day
• Air pollution levels (use EPA site)
6. Take a minute to try and identify what kind of soil you have collected. Common soil types include sandy, silty, clay-rich, loamy, peaty, and saline soils.

Step #3: Test Soil

Now that you have an idea for the type of soil at your collection site, let's look at its other properties. For this project, we're interested in the soil pH and its organic matter content. The pH tells us how acidic (or alkaline) the soil is. This factor influences the chemical reactions in the soil and as a result, the organisms living in it. Plants, for example, may have a hard time taking up nutrients if the soil is acidic enough to damage their roots. Soil organic matter represents the fraction of soil comprising of plant and animal detritus (the ecological term for remains). This measure can tell us how much biological activity is going on in the soil.

Test Soil pH

1. Place 3 teaspoons (12.6g) of soil in a clean container
2. Pour in distilled water until moist
3. Agitate the mixture well to form a soil slurry
4. Insert a pH test strip into the mixture. Acidic soil is indicated by red-yellow colors, while basic soil is indicated by green-blue colors.

If you don't have a pH strip, don't worry! You can get a sense for the soil pH using some baking soda and vinegar. Follow the instructions in Aidyl's video below.

Testing soil organic matter accurately usually requires laboratory equipment. For this citizen science project, this step is optional and should only be performed with appropriate laboratory equipment, ventilation, and adult supervision.

Optional: Observing Soil Organic Matter

1. Measure approximately 100 g of soil.
2. Allow the soil to air dry completely.
3. Record observations about soil color, texture, smell, moisture, roots, and visible organic material.
4. If you are working in a properly equipped laboratory, instructors may demonstrate a professional “loss on ignition” method used by soil scientists to estimate organic matter content.

Step #4: Prepare observation dishes

Before you extract nematodes from your soil, prepare clean Petri dishes or shallow clear containers to hold your sample. These dishes will be used for observing nematodes under a Foldscope or microscope. They do not need to be sterile for this citizen science activity.

1. With adult supervision, heat 240 mL of distilled water until hot but not vigorously boiling.
2. Dissolve 20 g of gelatin and 20 g of sugar into the hot water. Remove from heat.
3. Once the solution is cool enough to handle safely, pour it into a Petri dish or shallow clear container until it is about 2/3 full.
4. Allow the gelatin mixture to cool to room temperature and harden.

Step #5: Isolate the nematodes

Now we're ready to extract the nematodes. Using a simple filter and funnel apparatus, we will allow our nematodes to crawl their way out of the soil by themselves.

1. Create a funnel apparatus by fitting tubing onto the stem of a funnel, then closing the end of the tube with a binder clip or clamp.
2. Line the funnel with a coffee filter or paper towel.
3. Place a small amount of moist soil into the lined funnel.
4. Add enough distilled water so the soil is moist, and the lower part of the filter is in contact with water, but avoid flooding the soil completely.
5. Let the setup sit for several hours or overnight. Active nematodes may move out of the soil and collect in the water at the bottom of the tubing.
6. Open the clamp and collect a few drops of water onto a Petri dish or clear observation dish.
7. Use a Foldscope or microscope to look for nematodes and other microscopic soil organisms. Record notes, sketches, photos, or videos of what you observe.

Step #6: Upload your data!

We're not done yet! Contribute your observations to our community database so that others can see what you found. The database enables you to compare soil and nematode observations from your area with observations from around the world to better understand how factors like climate, human encroachment, and natural disasters are impacting the environment. After you've uploaded your observations, spend some time thinking about how you can analyze the observations in our database to learn more about the world around you.

1. Using the link provided to you by your teacher, or upon completing our New Participant Sign Up, visit our database and complete the form. Make sure to leave any comments or questions you have regarding this procedure, gathering materials, or navigating the database. Your feedback will help us improve our project for future citizen scientists!
2. Make sure to visit our site periodically to collect the latest data drop, an aggregate of the soil and nematode data uploaded by citizen scientists around the world. You can use this data to conduct your own research into any number of topics, including:
• Climate change
• Drivers of soil quality
• Nematode biodiversity