Organic matter determined by loss on ignition and potassium dichromate method

Soil organic matter content is one of the main issues of European soils and agriculture in general. Various methods are used to determine the organic matter. Most common approach is determining organic carbon from which organic matter is calculated as for example in wet combustion method by potassium dichromate and sulfuric acid. More robust, but easy-to-use method is loss on ignition (LOI) where soil is burned in muffled oven and the organic matter is determined from the weight loss. The aim of our research was to compare most commonly used method for determination of OM (potassium dichromate method) with LOI method on six different locations in Croatia, Serbia and Bosnia and Herzegovina. Our results showed good correlation between two different methods, although results of LOI method were somewhat lower from the potassium dichromate method. Our findings imply that correction factor used to convert LOI data into organic matter data should be adjusted for each location based on soil properties. However, good correlation suggests that values of one method can be easily predicted by regression analysis using the data from the second method.