Seasonal Dynamics of Surface Soil Bulk Density in a Forested Catchment

Bulk density is a commonly measured property during field investigations of soils. Accurate and reliable bulk density measurements are critical for assessing soil quality as well as for converting mass-based measurements to volume-based values. Our objective was to determine if there are significant seasonal changes to the measured bulk density of surface soil horizons in a forested ecosystem. The frame method was used to measure bulk density at monthly intervals for 12 mo at 10 locations within a forested catchment. The measured bulk density was variable with time for all plots, with the strongest seasonality shown in Oi horizons. Seasonal trends in Oe and A horizons were less pronounced. Particularly for O horizons, it appears to be critical to consider the time of year when collecting bulk density data.