Evaluation of carbon dynamics of calcareous soils amended with biochar under the application of low-voltage electrical chargeEvaluation of carbon dynamics of calcareous soils amended with biochar under the application of low-voltage electrical charge

Abstract

Among the important health parameters in soil, soil organic carbon (SOC), microbial biomass carbon (MBC), microbial respiration (CO2 ), water-soluble carbon (WSC) are the most affected parameters by environmental conditions. In this study, we investigated the effect of low-voltage electrical charged soil (VEC: 0mV - 3.5mV - 7.5mV) with biochar (BC) application on calcic Vertisol soil in terms of soil health parameters under laboratory conditions. At the end, 37-week measurement, the highest amount of soil CO2 -C emission was seen with a low-voltage electrical charged application of BC+7.5mV (12.89 mg CO2 -C kg-1 soil week-1), while the lowest amount was seen with the application of BC+0mV (1.31 mg CO2 -C kg-1 soil week-1). The Fourier transform infrared (FTIR) spectrum that displayed different functional group activities with all the application and the highest increases were observed in the alkyne (C-Br) (547 cm-1) and alkenes (=C-H) (964 cm-1) groups with BC application, while the lowest increases were seen with BC+7.5mV application. Examining the thermogravimetric (TGA) results, the smallest mass loss was observed with the BC+7.5mV application (24.98%), while the highest was with BC+3.5mV (21.41%). The highest breakdown in differential scanning calorimeter (DSC) was observed in BC-applied soil in the volatile C group [(EXO 1 (30- 200 °C)]. Especially in EXO 3 (385-475 °C), a high level of breakdown occurred, which was an indication of recalcitrant carbon groups. This study indicated that low-voltage electrical pulse was inappropriate for evaluation of soil C dynamics including SOC, WSC, MBC, and basal soil respiration.