Geosphere: Soil Respiration

Record the CO₂ released from various samples of soil, as soil respiration progresses. Compare data collected from different sites and identify differences in respiration rates for each soil sample.

Lab Summary:

In this exploration, students will use a carbon dioxide (CO₂) gas sensor to measure the carbon dioxide (CO₂) generated in diverse soil samples. Since CO₂ is a colorless and odorless gas, it is difficult to detect using our senses. The carbon dioxide (CO₂) gas sensor is a detection device that allows students to measure the CO₂ produced and determine a respiration rate from living, respiring organisms.

This activity will help students understand that soil is a living entity by exposing the biological attributes of soil. One way of studying soil life is by estimating the number of organisms (biomass) in a sample. Another approach to analyzing biological activity is the indirect measurement of CO₂ production from respiring organisms in the soil.

These data contribute to an understanding of the "soil life", without requiring the tedious classification of the organisms involved. Both direct and indirect methods can yield information regarding soil fertility, which is lucrative information for the agricultural industry.

Download free labs:

(student versions)

Computer-based lab (PDF, 600 KB)

Xplorer GLX-based lab (PDF, 80 KB)

Method:

Use a Carbon Dioxide (CO₂) Gas Sensor to measure the carbon dioxide (CO₂) generated in diverse soil samples.

Here's What You Need:

Required for computer-based lab:

(See lab download for Xplorer GLX-based lab requirements, which may differ)

Probeware

• PASPORT CO2 Gas Sensor (PS-2110)
• Xplorer GLX Graphing Datalogger (PS-2002)
  (or alternate PASPORT interface -- see other options)

Other Materials

• Wash Bottle and Waste Container
• Measuring Spoons
• Trowel or Digging Tool
• Protective Gear
• Soil samples
• Sealable plastic bags
• Permanent marking pen
• Pen or pencil

Lab Manual:

The computer-based activity is included in Explorations in Earth and Environmental Science (PS-2809). The Xplorer GLX-based lab is included in Earth and Environmental Science with the Xplorer GLX (PS-2821A). Both manuals are complete with Teacher Information pages, student instructions and handouts, and sample data.

For your convenience, we offer bundles which provide the probeware for the activities in the manual. For more, please see:
Computer-based Earth and Environmental Science Lab Manual and Bundles
Xplorer GLX-based Earth and Environmental Science Lab Manual and Bundles