Total Carbon and Nitrogen Deeper in the Soil Profile.

Historically, most soil C and N analyses have been done on shallow soil samples (<50 cm) with some sampling to 1 m.  In many soil profiles there can be substantial C and N below 1m, some of which is part of the coarse soil fraction (gravel and rocks great than 2mm in diameter).  We examined a variety of soils from different USDA soil orders to determine the amount of carbon and nitrogen present at depth and in the coarse fraction.  Up to 35% of C and N could be missed if sampling is not done below 1m.