In this lab, students will test two different soil samples, one from a natural environment and the other from a location impacted by humans, for their water-holding capacity, organic matter content, pH level, and nutrient content (nitrogen, phosphorus, and potassium).
At the end of this investigation, students will be able to determine that soil from a natural environment is ideal for plant growth as it is able to hold more water, has more organic matter, and has optimal pH and nutrient levels.
Soil components, human impact on soil, soil nutrients and pH level, water-holding capacity of soil, natural environment, organic matter, chemical fertilizers.
Pre-Lab: 40 minutes
Lab: 75 minutes
Post-Lab (questions): 40 minutes
- Abiotic and biotic factors interact within an ecosystem.
- People have positive and negative effects on the environment, both locally and globally.
B2. Investigate air, soil, and water quality in natural and disturbed environments, using appropriate technology.
B3. Demonstrate an understanding of some of the ways in which human activities affect the environment and how the impact of those activities is measured and monitored.
B2.2 Plan and conduct an inquiry, using appropriate technology, to compare soil quality in natural and disturbed environments (e.g., compare the phosphorous content, pH, organic matter content, water content, water-holding capacity, nutrient content, porosity, and/or bulk density of soil from a forest or meadow and soil from a garden or farmer’s field that has been treated with chemical fertilizer).
B3.1 Identify the basic components of soil, water, and air, and describe some of the effects of human activity on soil, water, and air quality (e.g., the effects of industrial or vehicle emissions on air quality; of chemical spills on soil quality; of chlorination on water quality).
- Soil is a mixture of organic matter, minerals, air, and water.
- Organic matter is plant and animal tissues along with bacteria and fungi.
- Humus helps soil hold water and helps provide plants with the necessary nitrogen, phosphorus, potassium they require.
- The darker the soil the more organic matter it contains.
- High level of organic matter in soil is beneficial because it has greater water-holding capacity and recycles more nutrients.
- Using chemical fertilizers instead of manure for a long period of time will reduce the organic matter in the soil.
- Using synthetic pesticides instead of natural pest control methods can make pests and weeds resistant to these pesticides.
- The optimal pH range for most plants is between 6.5 and 7.
Prior Skill Sets:
Students need to be able to make predictions and observations before conducting this lab as well as be familiar with the lab investigation process. Students also need to be able to complete all tables provided in the hand-outs neatly and accurately as well as work collaboratively with group members to complete all key aspect of this lab.
All soil content lessons need to have been delivered in the classroom and students need to have excellent knowledge of soil components, optimal pH and nutrient levels for plant growth, the importance of organic matter, and ways humans impact soil.
Materials and Equipment:
- Soil test kit (can be purchased at local stores like Canadian Tire, Home Depot, or Amazon.ca)
- 2 glass jars with tight-fitting lids (2 per pair of students)
- 2 funnels
- 2 filter papers
- 2 graduated cylinders (100mL)
- 1 tablespoon
- masking tape and pencil
- 2 medium sized ziplock bags
- Safety glasses
All soil content needs to be disposed of carefully in the organic waste bin that the teacher will provide. Students need to wear their safety glasses when using the soil test kits.
Instructional Planning and Delivery:
In this lab students will be testing two different soil samples, one from a natural environment (forest), and the other from a location impacted by humans (garden).
Tip: Visit a local natural environment to obtain your forest soil sample. Examples of local natural environments include Humber Arboretum, Etobicoke Valley Park, and Altona Forest.
Students will investigate the amount of organic matter and water-holding capability of both the forest soil sample and the garden soil sample. Furthermore, students will be testing the pH, nitrogen, phosphorous, and potassium levels of these two soils.
Hint: Forest soil is not treated with chemical fertilizers or pesticides while garden soil is.
Students will observe and note the characteristics of each soil sample before conducting their investigation. They will also make predictions on the results of their investigation using the knowledge of soil they have acquired in-class as well as from observing the samples.
Students will complete the hand-out entitled “Pre-Lab - Testing Soil Quality” (see attachment)
Tip: To encourage discussion, students will be working in groups (2-4 is suggested). Teacher will hand-out a sample of forest soil and a sample of garden soil to each group. These samples will be in labeled ziplock bags and will be used later by the groups to conduct their investigation.
Students will then share their observations and predictions with the class.
In this lab students are going to investigate the water-holding capacity, organic matter content, pH, nitrogen, phosphorous, and potassium levels of each of soil sample. They will be doing so in the order stated.
- Set up two graduated cylinders with a funnel in each and a folded filter paper.
Hint: Watch the following video https://www.youtube.com/watch?v=Ond_-SsiWE8
- Label each graduated cylinder using masking tape. One will be labeled forest soil and the other will be labeled garden soil.
- Place a filter paper in each of the funnels.
Hint: Watch the following video for filter paper folding instructions https://www.youtube.com/watch?v=Ond_-SsiWE8
- Add 2 tablespoons of forest soil to the filter paper in the graduated cylinder labeled forest soil and 2 tablespoons of garden soil to the filter paper in the graduated cylinder labeled garden soil.
Tip: Groups will be using the soil from the ziplock bags given to them during the Pre-lab exercises.
- Add 100 mL of water to the forest soil and time with a stopwatch how long it takes for the water to go through and record your observations in the table on the hand-out entitled “Lab: Testing Soil Quality”. Do the same for the garden soil.
Organic Matter Content
- Obtain two glass jars with lids
- Label one jar with forest soil and the other with garden soil.
- Fill halfway the jar labeled forest soil with forest soil. Do the same with the jar labeled garden soil.
- Add water leaving only approximately 1” (2.5 cm) of space at the top.
- Tighten jars with lid and shake vigorously for about 30 seconds.
Tip: Shake jars longer if clumps are present in the sample.
- Observe the different layers in the two samples.
Hint: The floating layer at the top will be the organic matter.
Tip: For best results let the jar sit undisturbed for about 24 hours.
- Compare the amount of organic matter in the two jars and record the observations in the table on the hand-out entitled “Lab: Testing Soil Quality”.
pH and Nutrient Test
Following the instructions of selected soil test kit, complete pH, nitrogen, phosphorus, and potassium test. Instructions may vary depending on the kit purchased. Groups will record their results in the table on the hand-out entitled “Lab: Testing Soil Quality”.
Tip: Watch the following video to get a general idea on how to use a soil test kit: https://www.youtube.com/watch?v=qcH9aYIbgF4
Related Background Resources:
Craven, Kirsten, Craven, Meaghan, & Shields, Tom (2010). Environmental Science Interactions. Ontario: Edvantage Interactive.
The Ecology Center. (2017, February 6). Soil Testing: The Jar Method.
See attached hand-out entitled “Rubric: Testing Soil Quality”.
Students can go on a field-trip to a local natural environment prior to engaging in this lab to collect the natural environment soil samples.
Hint: Examples of local natural environments include Humber Arboretum, Etobicoke Valley Park, and Altona Forest.
- Lab report writing skills can be incorporated into this lab by asking students to write a formal lab report to interpret their observations and results. A lesson to teach the different sections of a lab report would be required. The hand-out entitled “Lab: Testing Soil Quality” would not be given to students as they would be asked to produce their own table to record their results.
- After completing this lab, students can research simple scientific articles using websites such as www.sciencedaily.com that relate how human activity is altering soil composition. They then can summarize their finds in a creative and visual way and present it to the class.
Tip: Students can use technology tools, such as PowToon and Prezi, to summarize their article.
Hint: This article is a good example “Human activity affecting microbes in soil”. https://www.sciencedaily.com/releases/2015/09/150923134442.htm
- Students can conduct a soil problem activity where the teacher will provide students with a defective soil sample and students will have to select tests to use to determine its quality. Once finished, students will brainstorm ideas on how to enhance the soil to make it ideal for crop growth and apply these to their soil sample. Once their soil is ready, students will grow specific vegetables (corn, tomatoes, and beans) in the soil. See the hand-out entitled “Growing Vegetables: Fact Sheet” below for information on how to grow these vegetables.
Tip: Provide students with a copy of the hand-out entitled “Growing Vegetables: Fact Sheet”.