Resumen

IRIZAR, Alicia; ANDRIULO, Adrián; COSENTINO, Diego  y  AMENDOLA, Catalina. Comparison of two physical fractionation methods for soil organic matter. Cienc. suelo [online]. 2010, vol.28, n.1, pp.115-121. ISSN 1850-2067.

Regression analysis was used to compare particulate organic carbon (COP) and light carbon (Cs) concentrations obtained by size (fraction > 53 µm) and density fractionation (liquor density = 2 g cm^-3) methods, respectively. The soil samples were taken from a long-term experiment located at the EEA-INTA Pergamino comparing four cropping sequences and two tillage systems. Both methods were linearly and positively correlated to depths of 0-5 and 5-10 cm and the y-intercept did not differ from zero, indicating that both methods resulted in a similar estimate for labile C. As the slopes did not different from unity, the differences between the two methods remained constant throughout all the labile range measured. There was no correlation for a depth of 10-20 cm, and Cs concentrations were higher and less variable than those of COP. The liquor density used might explain the obtention of similar or greater amounts of Cs than of COP because of the important contribution of the organomineral complex to the light fraction.

Palabras clave : Particle-size fractionation; Density fractionation; Labile organic matter.

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