The soil block test: Potential for improving our understanding of the role of soil source on performance

The soil block test is widely used in North America for evaluating the decay resistance of various wood-based materials. One drawback of this test is that soils from different sources may result in variable wood weight losses. Developing more definitive screening criteria for soils would help select soils that would be most appropriate for use in these procedures. Soils from seven different sources were characterized for soil texture, pH, water holding capacity, C:N ratio, bulk density and then used in soil block tests against two white rot and two brown rot fungi. While there were substantial differences in soil characteristics, none of the parameters were correlated with wood weight loss. The results illustrate the difficulty in predicting fungal behavior in laboratory tests based upon soil characteristics.