Detection of carbon content changes after biochar application on agricultural field experiment using both method walkley-black and thermogravimetry

Introduction new methods for analysing samples is associated with comparison with standard methods. Thennogravimetry (TG) works on principle of monitoring thenual mass losses (TML) of samples in depended on temperature or on time during heating up, e.g. Determination of SOC content at 550 degrees C in muffle furnace during several hours. More detailed analyses of TML dynamics can provide more accurate and reliable data. Here are presented results of SOC content determined by TG (TML320-330 which correspondent temperature between 320 to 330 degrees C) compared with results determined by standard method (Walkley-Black. WB) on the samples from field experiment with biochar addition (0, 15, 30, 45 dm) in combination with mineral and organic fertilizer. The soil samples were sampled in 2 depths (0-0.1 and 0.1-0.2 m) in autumn 2016. The results determined by TG show significant underestimation of SOC content comparison with WB method. Biochar addition records TG at higher temperatures (for our samples by TML around 400 to 550 degrees C for both fertilizer management).