GONCALVES, Rodrigo; VELOSO, Abel; SIMOES, Maria Paula    HORTA, Carmo. Soil organic matter evaluation using two different methods in peach orchards from the Beira Inteior - Portuguese centre region. []. , 45, 4, pp.341-350.   01--2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28466.

Soil organic matter (OM) quantification is of great importance to evaluate soil fertility and its capacity for carbon storage. Walkley-Black (WB) and loss on ignition (LOI) are two of the most common methods for OM quantification. WB method has been used to quantify the readily oxidizable OM. The main objective of this study was to evaluate the adequacy of these two methods for OM quantification in soils from the Portuguese inland centre region. A total of 49 soil samples (0-30 cm) were used. In LOI method, the samples were incinerated at 450ºC for 16 h and then at 800ºC for 4 h. Low weight losses were found when the samples obtained from the LOI method were incinerated at 800ºC for 4 h. Despite the higher values obtained from the LOI method, a good correlation was found between that method and the WB method (R 2 =0,636, P<0,001). The difference between the values obtained from the two methods indicates the more stable fraction of OM in soil which contributes to the long-term C storage.

: organic matter; carbon storage; Walkley-Black; loss of weight on ignition.

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