SYMPOSIA PAPER Published: 01 January 1970

Suggested Method of Test for Organic Matter Content of Soils by Redox Titration


This method is applicable to the rapid approximation of the amount of organic matter found in soils. Since the precise effect of organic matter content on any of the engineering properties of soils is not generally known, this test is intended to guide the engineer by evaluating the relative amount of organic matter present. It is not a precise determination. The method is based on the oxidation of carbon and inherent in the calculation is an assumption that organic carbon multiplied by 1.72 equals organic matter. Thus the more accurate, but also more complicated and more time-consuming wet combustion method for organic carbon could be used, with the carbon content multiplied by 1.72 to approximately yield organic matter. Actually, the ratio of carbon in soil to organic matter ranges from 1.7 to 2.0. The organic matter measured in most cases will be derived from decayed animal and vegetable matter.

Author Information

Rankin, WL
Rankin Testing Laboratory, Omaha, Nebr
Price: $25.00
Contact Sales
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Developed by Committee: D18
Pages: 286–287
DOI: 10.1520/STP38518S
ISBN-EB: 978-0-8031-5570-1
ISBN-13: 978-0-8031-0051-0