Evaluation of the surface affinity of water in three biochars using fast field cycling NMR relaxometry

Many soil functions depend on the interaction of water with soil. The affinity of water for soils can be altered by applying soil amendments like stone meal, manure, or biochar (a carbonaceous material obtained by pyrolysis of biomasses). In fact, the addition of hydrophobic biochar to soil may increase soil repellency, reduce water-adsorbing capacity, inhibit microbial activity, alter soil filter, buffer, storage, and transformation functions. For this reason, it is of paramount importance to monitor water affinity for biochar surface (also referred to as 'wettability') in order to better address its applications in soil systems. In this study, we propose the use of fast field cycling NMR …