Loss‐on‐Ignition in the Determination of Pools of Organic Carbon in Soils of Forests and Afforested Arable Fields

Abstract

Loss‐on‐ignition (LOI) and concentration of organic carbon (Cc) were determined on pristine forest soils and soils from afforested arable fields. The objectives were to investigate the relation between the Cc of soil estimated indirectly from LOI and true Cc from dry combustion (C_LECO) and further to evaluate how the applied analytical method affects the carbon pool estimates. According to results, LOI was a good indicator of Cc in the organic layer. As regards mineral soil, however, C_LECO/LOI ratio significantly decreased with increasing depth, and the ratio changed differently in soils underlying forest sites as opposed to the soils from former fields. The results indicate that estimation of carbon pools from conversion factors would lead to considerable bias and that direct measurement of Cc is preferable to the use of any Cc/LOI ratio. The results also emphasize the need for elimination of carbonate carbon when measuring Cc from the soil of arable fields.

Keywords:

• Arable land
• carbonate carbon
• carbon pool estimation