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Subject: Soil Science × Author: Gaur, Divya × End date: 2019 × Start date: 2019 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Comparison of methods of organic carbon determination in Soils of Haryana
    (CCSHAU, 2019) Gaur, Divya; Dev Raj
    A study on “Comparison of methods of organic carbon determination in soils of Haryana” was conducted during 2018-19 in Department of Soil Science, CCSHAU, Hisar. For this study 80 surface and 80 subsurface samples were collected from 4 soil orders Entisol, Inceptisol, Aridisol and Alfisol of Haryana. After analysing basic properties, three methods of soil organic carbon determination viz: Walkley Black method, Colorimetric method and Dry combustion (CHNS analyser) were used for determining the organic carbon content in soil and their per cent recovery and correction factors were find out. The pH of these samples was found in alkaline range and EC varied from 0.40dS m-1 to 1.25dSm-1. Highest Sand and calcium carbonate content were observed in Aridisol while Silt and Clay content found highest in Alfisol. Available nutrients (N, P, K and S) showed high positive correlation with OC content and clay content of soil. The OC content and available nutrients were found highest in surface samples of Alfisol while lowest in Aridisol. Very labile and labile fractions of OC represented major fraction in Aridisol while recalcitrant fraction of OC found highest in Alfisol. A higher OC content was measured by dry combustion method compared to wet oxidation methods in all the samples collected from different orders. The per cent recovery of OC content in soil by Walkley Black and Colorimetric method follows the order: Aridisol>Entisol>Inceptisol>Alfisol. The Correction factor for Walkley Black method for surface samples of Entisol, Inceptisol, Aridisol and Alfisol was found 1.52, 1.59, 1.22 and 1.67, respectively while for subsurface samples of these orders correction factor was slightly higher i.e. 1.54, 1.63, 1.25 and 1.69, respectively. Colorimetric methods shows the values of OC content close to dry combustion method and hence the correction factor is slightly less i.e. 1.16, 1.19, 1.06 and 1.31 for surface and 1.18, 1.22, 1.08 and 1.34 for subsurface samples of Entisol, Inceptisol, Aridisol and Alfisol, respectively. It can be concluded from this study that the above correction factors can be used for determining the accurate amount of OC content in soil in soil testing laboratories of Haryana state for making precise recommendation of nitrogenous fertilizers.