COMPARING WET CHEMICAL METHOD FOR DETERMINING SOIL ORGANIC CARBON AND NITROGEN IN PADDY SOILS WITH CNS ANALYZER METHOD

DOI: http://doi.org/10.55706/ijbssr13205

In developing countries like Bangladesh, due to lack of advanced equipment like the Variomax CNS Analyzer, soil organic carbon (SOC) and nitrogen (N) are typically measured using Wet Oxidation and Kjeldahl methods. This study compared these traditional methods with CNS Analyzer results by using 47 soil samples from various AEZs, representing rice-based cropping systems of Bangladesh with diverse soil textures, organic matter, pH, and management.Kjeldahl analysis showed total N ranging from 0.369% (Gorargao) to 0.067% (Brahmaputra), while Wet Oxidation recorded SOC from 3.5% (Sonatola-1) to 0.546% (Tarakanda). Higher N and SOC were found in clay soils, lower in sandy ones. From the correlation study Strong correlations were found between CNS and traditional methods (R² = 0.76** for N, 0.67** for SOC). Paired t-tests showed no significant differences, despite average underestimations of 9.77% (N) and 9.92% (SOC) by traditional methods. Soil texture was a key source of error, with clay content positively correlated with % error in N and SOC (r = 0.43** and 0.34*, respectively).