Correction of Bulk Density and Sampling Method Biases Using Soil Mass per Unit Area

This study compared linear depth from the soil surface vs. equivalent sample mass for interpreting soil water content and concentration data. Our first experiment sampled soils that differed only in surface bulk density. A second experiment compared different soil sampling tools. In both cases, analysis by mass instead of depth corrected water content discrepancies caused by bulk density or sample compaction differences. In a third experiment, samples collected from an on-farm test resulted in many significant differences in soil moisture between tillage practices for linear depth data that did not exist when analyzed using equivalent sample mass. When it is important to avoid confounding bulk density, depth from the surface, or sampling method with quantitative measurements, sampling by mass instead of volume is more accurate and precise than many quantitative methods currently in use, and represents an important advance in our ability to make comparative measurements across time, treatments, locations, and equipment.