Tuesday, April 30, 2013

Decomposing with Cotton Strips...the beginner's guide!

Simple cotton strips can be used as a surrogate for other organic matter (leaves etc.) in the study of decomposition.  Decomposition is measured by the loss of tensile strength in the buried strip!

Positioning Your Strips
             It is important that the strips are randomly placed in your garden. To ensure this take a small object (stick etc.) and toss it "blind" over your shoulder into your plot!  This will be your "central point. (see diagram)
           The strips will be positioned around this central point.  They should be arranged as a triangle with each point about the distance of your foot (assuming it is an average foot!) with the central point occupying the center of the triangle. (see diagram)

Inserting the strips into the soil.  NB For this you will need a garden spade
       The strips are placed into the soil vertically.  When they are properly placed the top (marked with a label) will be uppermost and will stick out of the surface. (See photos).  BEFORE placing them in the soil a slot for each strip should be opened up with the spade.  Push spade into the soil to the approximately 9 inches.  Move the spade back and forward a little to ensure that the strip will go in effortlessly.

      Remove the space and lay the strip along the length of the space.  The label (plastic tape) will be towards the top of the spade (closest to the handle).  Wrap the very end of the strip (where it is marked with a blue line) around the tip of the spade.

      Reinsert the spade with the strip into the soil.

   Carefully withdraw the spade leaving the strip into the ground.

     Tamp around the edges of the ground close to the strip to ensure there is good contact between the soil and the strip.

     You are done with this strip!  Repeat steps 3-7 for the remains strips (completing the triangle).

Last Step: The Control Strips
        This is a vital last step.  Pick a point close by to the other strip and repeat steps 3-7 with each of the 2 control strips but this time as soon as you are done remove the control strips.
          When removing the strip ensure that they come out with minimal effort.  If necessary loosen the soil with a trowel, taking care not to damage the strips.

     Store the controls in a place where they remain dry until returning all strips at the end of the experiment.  

Removing the Strips
       The strips should remain in place for 28 days (4 weeks).
      To remove the strips loosen the soil around each strip with a trowel (or comparable garden tool) making sure that you do not damage the strip. 
      When the soil is loose gently ease the strip out of the ground.
       Place all strips into the self-addressed envelope that we have provided (along with the control strips) and returned them immediately.

DePaul Environmental Science Student, Alexandra Patrickus, proudly holding a Cotton Strip.

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