ISSUES CONCERNING THE DETERMINATION OF ORGANIC CARBON IN SOILS THROUGH COMBUSTION PUBLISHED

Lavinia MOLDOVAN, Marilena MĂRGHITAŞ, Mihaela MIHAI, C. TOADER
In agrochemical methodology for the determination of the determination of the organic-C content, an implicitly the humus content, several procedures have been acknowledged. These procedures involve dry or wet combustion, followed by a titrimetrical, or rather a gravimetrical dosage of the humified organic matter. Based on the capacity for dry or wet combustion (employing acid oxidizing mixtures) it is thus obvious to come to differentiated results in methods (procedures) related to the humus (organic-C) quantity and quality, to the level of evolution-humification and destruction of the organic matter. These differences may be caused by the fertilizing organic resources (wich are to be found in the soil and prove active during the process of the humification). The paper and determinations conducted on different soils, in terms of humus supply and agrochemical treatments, regularly show that differences appear in favor of the results obtained through dry combustion, with a more energetic oxidizing-destruction in soils that are well-supplied with organic-C. In these cases, the mentioned fraction is more stable as a consequence of superficial nitrogen bioaccumulation. In soil samples containing humus in a predominantly pozitive evolution and also humic fractions (of the organic-C) in stabilization (destruction and synthesis), the determined values are variable and are not always subject to clear differention rules.Therefore, out of the organic-C values determined throgh dry, respectively wet combustion, the establishment of certain correlations appears necessary for the interpretation of the global carbon cycle . The purpose of this research resides in setting an interpretation methid that would certify the comparison of methods obtained in determining organic carbon (dry and wet combustion). In this respect, the interpretation at hand shows varied and comparable possibilities in assessing average and long-term evolution of organic-C soil reserves.
carbon, humus, dry combustion
Presentation: oral

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