The increased emissions of greenhouse gases have motivated researches about capture and sequestration of C. The use of biochar in soils is an efficient way to maintain the C in the biochar stabilized and benefit the crop yield. The objective of this research was to characterize charcoals collected at different places.It was determined: total and organic C contents; elementary analysis by calcination; characterization of the samples by X-ray diffractometry, absorption spectroscopy and scanning electron microscopy. The samples in contact with soil showedhigher TOC contents, while total C contents were higher in the charcoals without contact with soil. The pH-H2O values of charcoal samples in contact with soil ranged between 4,42-7,24, average 6,8, while pH-KCl values ranged between 2,91-6,88, average 4,68. All samples presented low nutrient contents. In the samples of charcoal in contact with soil,kaolinite, quartz, graphite and gibbsitewere detected.The main functional groups identified were O-H, C=O, C=C and C-O. In the SEM of thesamples 1 and 2,wood structures were less evident and there was influence of the soil components and organisms in these charcoals.
Biochar; Carbon sequestration; Reactivity
