Biochar and it's characterisations.

NMR provides a powerful tool for studies of compositions of Biochars. However, the usual NMR procedures used for humic and SOM studies do not meet specific requirements for Biochars because pyrogenic materials present strong local magnetic susceptibility heterogeneities. Our data show that uses of CSA-filter and TOSS techniques make the pulse sequences very sensitive to imperfections in the pulses. We will show how we have used Variable Amplitude CP - (VACP)/MAS spectra and composite pulses in the CSA-filter and TOSS pulse sequences. In that way the component functionalities in a humic acid (HA) from a Terra Preta soil were successfully determined. Other techniques will be discussed