BugWise

Plywood with grid paper placed on the ground can be used to measure decay rate. Photo: © Australian Museum.

Paper is a product derived from plants. This method uses paper to simulate naturally occurring organic material such as leaf litter. The grid lines allow the observer to more accurately estimate the percentage of the paper that has decayed. When measured as a function of time, this method allows an easy way to track rates of decay at the soil surface.

What you will need

• Plywood cut into 10 cm x 10 cm squares
• Grid paper (1 cm x 1 cm squares) cut into 10 cm x 10 cm squares
• Compass
• Pair of secateurs or small hand trowel
• Bamboo canes (approximately 40 cm long)
• Pencils and data sheets for recording

Method

• Describe your site.
• Combine the plywood and grid-paper and randomly distribute them within the site. Try to avoid large rocks and logs, as the paper must sit flat on the ground.
• Before placing the paper and plywood on the ground first remove the surface litter from an area, approximately 11 cm x 11 cm. Place one of the sheets of paper on the bare soil and cover it with one of the plywood squares. Ensure that the ply is sitting flat on the surface of the soil, tap it lightly to settle it, if required.
• So that you can relocate each of the ply-grid paper bundles, place a bamboo stake flagged with a piece of coloured flagging tape to the north of each point.
• After about eight weeks carefully turn over each piece of ply and record the number of 1 cm x 1 cm grids that have decayed.
• Record your methodology. For example, how many plates you put out.

Tips

When repeating the method, make sure that you choose 'new' random spots within your site. When the method is repeated the results can be charted over time to detect trends.