Agriculture & Food, Volume 9, 2021

Abstract: Biochar, which can be used for improving soil fertility, is a carbon rich, heterogeneous, and chemically complex material. It is known that biochar ab/adsorbs nutrients, but there is still a lack of knowledge regarding these effects. To investigate the ability of biochar to adhere nitrogen an in-vitro experiment was conducted. Different inorganic (ammonium, nitrate, and ammonium nitrate) and organic 15N sources (urea; valine, phenylalanine, isoleucine, and glutamic acid; also yeast protein as a high molecular weight compound) were added to Pyro-biochar and to HTC-biochar to estimate retention after 15 and 30 days, and also to examine the effect of washing on 15N. The 15N in-vitro retention (%) of 15N-inorganic and 15N-organic substances at Pyro-BC and HTC-BC, at days 15 and 30, was less than 10% for both biochar’s. This amount could substance specific clearly reduced by washing. The high molecular weight 15N yeast protein adhered to 30% for HTC-biochar, which was 3-fold higher than for Pyro-biochar. Therefore, the manufacturing process of the two biochar’s had a significant impact on in-vitro retention. The functional groups, and therefore Van-der-Waals-interactions, chemical reaction, the affiliation of amino acids and the molecular size of compounds, such as yeast protein, can affect the 15N retention of these substances.