Investigating Soil Effects on Outcomes of a Standardized Soil–Block Test

Abstract

Soil physical and chemical properties play important roles in mass loss during soil–block tests but the relationship between soil properties and the decay caused by brown-rot and white-rot fungi remains unclear. The objective of this study was to investigate the soil effects on the decay resistance of pine (Pinus spp.) and poplar (Liriodendron tulipifera L.) blocks. The properties of soil from nine different sources (six from Idaho, one from Mississippi, one from Wisconsin, and one from Oregon) were characterized for soil texture, sieved bulk density, water-holding capacity, pH, organic matter, and carbon and nitrogen concentrations. The moisture content and mass loss of decayed wood samples after 8 weeks of fungal exposure were measured. At the end of the study, block moisture ranged from 30 to 200 percent and mass loss ranged from 20 to 60 percent. Despite using a range of soils, there were no direct correlations between soil properties and wood-block moisture content or mass loss. Moreover, among all the soil properties examined, no significant effect of a single soil property on wood-block moisture content and mass loss was measured. Instead, the combined effects of soil physical and chemical properties may interact to govern the decay of wood blocks in the laboratory soil–block test.