Making collars for LI-COR soil chambers

Follow these guidelines if you want to make your own soil collars. If you construct a collar from a material with a different inside diameter than that of LI-COR soil collars, be sure to recompute the chamber volume and use the new volume in flux calculations.

You can make your own collars if you can acquire suitable pipe. Large soil collars from LI-COR are constructed from thick-walled, 8-inch SDR 35 PVC pipe. This material is widely available in the United States. In other countries, you may need to special order the PVC pipe or find a similar alternative.

To construct a collar, cut a length of pipe to approximately 11.43 cm. Then, use a grinder or coarse file to bevel the bottom edge to a 24° angle. The bevel is optional but does allow for easier insertion of the collar into the soil.

  • Inside Diameter: 20.1 cm ± 0.03 cm
  • Outside Diameter: 21.34 cm
  • Height: 11.43 cm
Large soil collars (20 cm) can be constructed from PVC pipe.