Usta, SadıkAşık, Sezin2022-04-292022-04-292008http://hdl.handle.net/20.500.12575/79902In this study, 14 liquid soil conditioners containing humic acid were supplied by various companies and their physical and chemical properties as well as information on functional groups contained by them were found. The results obtained by analyzing these samples were compared with the values for pH, total humic+fulvic acid amount, K2O amount soluble in water and total organic matter amount existing on their labels. Moisture and dry matter amounts, densities, ash amounts and organic carbon values of these samples under study were also determined to discover their features and to evaluate them. Different methods were employed in determining moisture-dry matter weight, organic matter and organic carbon and the evaluation was made among the results. Also, carboxyl and fenolic hydroxyl groups existing in chemical structure of these humic acids and their total acidity values were investigated. According to the results of the analyses, humic acid contents of the samples range between 7.96%-22.04%. As a result, variations were seen between total humic+fulvic acid amount given on labels and those obtained from the analyses. Humic acid contents of five of the samples are below the threshold specified by Agricultural Ministry for soil regulators. Three samples gave results consistent with those given on their labels whereas five samples gave results below those given on their labels. Only one sample has a higher value than that shown on its label. Also, because it was found that the results obtained from the test, which is used in determining samples? organic matter contents in which the sample was subject to dry burning at 550 oC for 3 hours and also is mentioned in regulations, cause troubles, `at 550 oC for 5 hours?, `at 700 oC for 3 hours? and `Walkley-Black? methods were employed. As a result, it was seen that the most reliable results were obtained at 700 oC for 3 hours. In functional group analyses done to determine structures of humic acids, -COOH groups range between 1.11-4.84 meq/g, phenolic-OH groups range between 1.28-7.43 meq/g and total acidity range between 5.46-8.66 meq/g.tr-OHWalkley-BlackmasterThesis