Use of the Leco Automatic 70‐Second Carbon Analyzer for Total Carbon Analysis of Soils

Studies with surface and subsurface soils containing 0.3–34% organic carbon and with carbonate standards showed that the Leco automatic 70‐second carbon analyzer is satisfactory for determination of total carbon in soils. The Leco procedure evaluated involved high‐temperature combustion of soil with a high‐frequency induction furnace in a stream of purified oxygen and measurement of the carbon dioxide evolved by a thermal‐conductivity technique providing automatic readout of the carbon content of the sample. With all soils analyzed, the results of total carbon analysis by the Leco analyzer agreed closely with, and were as precise as, those obtained by the wet‐combustion method of Allison. Total carbon analysis of soils by the Leco analyzer is very simple and rapid, and a single operator can easily perform more than 150 analyses in a normal working day.