1. This appendix consists of two sections. Section 1 describes the 

 basic procedure for digging a soli pit and examining for hydrlc soil Indica- 

 tors. Section 2 is a list of hydrlc soils of the United States. 



Section 1 - Procedures for Digging a Soil Pit and Examining 

 for Hydrlc Soil Indicators 



Digging a soil pit 



2. Apply the following procedure: Circumscribe a 1-ft-dlam area, pref- 

 erably with a tile spade (sharpshooter) . Extend the blade vertically down- 

 ward, cut all roots to the depth of the blade, and lift the soil from the 

 hole. This should provide approximately 16 inches of the soil profile for 

 examination. Note: Observations are usually made immediately below the 

 A-horizon or 10 inches (whichever is shallower) . In many cases, a soil auger 

 or probe can be used Instead of a spade. If so, remove successive cores until 

 16 inches of the soil profile have been removed. Place successive cores in 

 the same sequence as removed from the hole. Note: An auger or probe cannot 

 be effectively used when the soil profile is loose, rocky y or contains a large 

 volume of water (e.g. peraquic moisture regime). 



Examining the soil 



3. Examine the soil for hydrlc soils indicators (paragraphs A4 

 and/or 45 of main text (for sandy soils)). Note: It may not be necessary to 

 conduct a classical characterization (e.g. texture, structure, etc.) of the 

 soil. Consider the hydrlc soil Indicators in the following sequence (Note: 

 THE SOIL EXAMINATION CAN BE TERMINATED WEEN A POSITIVE HYDEIC SOIL INDICATOR 

 IS FOUND) : 



Nonsandy soils . 



a. Determine whether an organic soil is present (see paragraph 44 

 of the main text). If so, the soil is hydrlc. 



b. Determine whether the soil has a histlc epipedon (see 

 paragraph 44 of the main text) . Record the thickness of the 

 histlc epipedon on DATA FORM 1. 



£. Determine whether sulfldic materials are present by smelling 



the soil. The presence of a "rotten egg" odor is indicative of 

 hydrogen sulfide, which forms only under extreme reducing con- 

 ditions associated with prolonged inundation/soil saturation. 



d. Determine whether the soil has an aquic or peraquic moisture 



regime (see paragraph 44 of the main text). If so, the soil is 

 hydrlc. 



D2 



