Field Indicators of Hydric Soils

Patuxent Wildlife Refuge and Beltsville Agricultural Research Center


The scepter of the wetland frog.


Steve Harman of the Baltimore District of the U.S. Army Corps of Engineers was the lead organizer of the two-day hydric soils class.


Lenore Vasilas discuses terminology, technical standards, methodology and monitoring documentation.


The installation of a monitoring well, consisting of digging the hole with an auger, then installing the piezometer PVC tubing, and automated Onset HOBO well reader data loggers.  The pre-slotted PVC piping is made from a company out of Georgetown, DE.  Lenore showed us her method of installation using auger, sand and pelletized bentonite mixed with soil near the surface, then sloping away from the well tubing.


Kevin checks-out the University of Maryland, Martin Rabenhorst IRIS Tube.


The pink of an A-A-Dip test.


Yes, we are standing on a PEM1A/B wetland.

Remember its pore linings now, not oxidized rhysopheres.  Important redoxomorphic features may include mottles being splotches on ped faces, color contrast, accumulation or depletion, soft masses and concretions, plaques on roots, coated grains on sand being a hydric indicator, whereas non-coated sands will stay white and may not be considered hydric.

Many of the Maryland floodplains are flashy, with flooding being rather frequent and brief, and most having evidence of post colonial deposition.  We saw test pits with post colonial soils (bottomland) over former wetlands, piedmont soils in the coastal plain and adjacent upland soils from former tobacco farming.

Did you know that soil surveys can have up to a 1.4-acre “fudge-factor” (margin of error) and the soil lines on mapping are between 35 and 75-feet wide!  If soil can be mapped at 1.4-acres in size or larger, then it will.


PDF Attachment:  Protocol for Using and Interpreting IRIS Tubes, M. Rabenhorst, 2008.   Protocol_IRIS_Tubes

PDF Attachment:  Using IRIS Tubes for Monitoring Reduced Conditions in Soils, J. Berkowitz, 2009.   tnwrap09-1