Comparison of dry combustion and Walkley-Black methods for the determination of organic carbon distribution in soil profiles
1942
Hutton, C.E. | Simonson, R.W.
The recoveries of carbon by the Walkley-Black method are compared with data previously obtained by a dry combustion method for the principal horizons of 12 soils representing six Great Soil Groups. Variations in recovery of carbonrange from 53 to 79% in the separate horizons of some profiles, and they reach the same order of magnitude when the same horizons in widely different soils are compared. The smallest deviations occur when data for one horizon in a number of profiles belonging to a single Great Soil Group are compared. It would appear, therefore, that approximate values for organic carbon can be obtained by means of the Walkley-Black method, but the variations in recovery are often large enough to obscure important differences between the various horizons in the same profile or similar horizons in different profiles. The deviations in recovery of carbon are considered too large to permit the general use of the more rapid procedure for the study of carbon distribution in soil profiles.
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