Direct measurement of organic carbon content in soils by the Leco CR‐12 carbon analyzer

A straightforward procedure is described for soil organic carbon (C) measurement in soil samples that may contain carbonates by using the Leco CR‐12 Carbon Analyzer. At a temperature of 840°C, a measured oxygen flow of 3.6 L min‐1, lancing flow of 1.0 L min‐1, soil organic C content can be directly measured on 0.20 to 0.40 g of samples, which have previously been ground to pass 40‐mesh sieve, for most medium‐ and fine‐textured soils. The organic C is combusted and measured within 2 min. A larger sample size of up to 2.5 g is suggested for sandy soils of low organic C content.