Many persons have recently discovered soil biology at hand of simple demonstration tests – a “popular” one being “soil my undies”, where a pair of briefs are buried randomly in soil and unearthed a little later to see to what extent the cotton fabric has decomposed. Other variants have emerged that are as equally interesting as difficult to interpret including a teabag test with rooibos tea leaves that are recovered semi-intact in the bag at a later point in time and dried and weighed. There’s a margin of error in these tests due to fine soil particles that adhere to the material, but it serves to enable semi-quantitation.
An approach introduced by Woods End is to use distinct classes of materials – to observe visually how they survive soil treatment. One is cough-sticks (hardwood) which are buried and recovered to count (and weigh) the remainder of the material. The results of examining differing soil orders across the USA for wood decay are seen in the image below, showing huge differences depending on what type of soil a stick is buried in.