Characterization of pore size distributions within soils by mercury intrusion and water-release methods

I measured and interpreted soil pore size distributions for undisturbed, oven-dried peds using mercury intrusion porosimetry. The pore size distributions were compared with those calculated from moisture release data. A correlation between water retention difference by water-release methods and water storage pore volumes (50 to 0.5 μ) by mercury intrusion was established with an R²= 0.58 over a variety of soil texture and bulk density ranges. Most of the variation occurred for soil samples high in either sand or clay. In addition, root-restricting class limits were developed based on volume of root size pores (200 to 10 μ) within oven-dried peds that were large enough to permit root tip and root hair penetration.