IHSS&IWA26 / BRNO / CZECHIA / 23–28 August 2026 BOOK OF ABSTRACTS 136 Soil Organic Matter, Caustobiolites, and Biochar Thursday, 27 August 2026 / Hall B increased BR in the same way as HC and stimulated specific enzyme activities. Arylsulfatase showed a positive, dosedependent response irrespective of irrigation regime, indicating stimulation of S cycling processes in soil. Under WD, FDA hydrolysis increased at an HS dose equivalent to 20 t ha⁻¹ HC compared to CTR. The remaining enzyme activities were unaffected. These preliminary results indicate that HS may partially account for the stimulation of microbial activity by HC observed in other experiments[3], pointing to mechanisms beyond simple nutrient supply. The findings support the hypothesis that specific bioactive fractions within HC may contribute soil microbial functioning, potentially influencing plant performance. Our results demonstrate further that aside the impact of BC and HC on soil chemistry, additional mechanisms exist that so far have been largely underrated. They evidences that the nature of their organic fraction can play a crucial role in regulating both soilbiochemical processes and even plant response. References 1. Garcia-Rodriguez, A.F.; Moreno-Racero, F.J.; Garcia de Castro Barragan, J.M.; ColmeneroFlores, J.M.; Greggio, N.; Knicker, H.; Rosales, M.A. HORTICULTURAE 2022, 8, doi:10.3390/ horticulturae8121214. 2. Garcia-Rodriguez, A.F.; Moreno-Racero, F.J.; Álvarez, R.; Colmenero-Flores, J.M.; Knicker, H.; Rosales, M.A. Plant Soil 2026, 518, 299–317, doi:10.1007/s11104-025-07997-0. 3. Moreno-Racero, F.J.; Velasco-Molina, M.; LópezNúñez, R.; Knicker, H. Hydrochar as a Modulator of Soil Microbial Activity and Soil Biochemical Processes. Preprints 2026, doi:10.3390/ agronomy16090917 Acknowledgement This work was supported by the Black to the Future Project, (EIT-21217), the Marie Skłodowska-Curie Grant (No 895613), the Junta de Andalucía and the European Regional Development Fund through SequestCarb (PY20_01065), the PhD scholarship (PREDOC_00339) and the Spanish National Research Council (JAE Intro-ICU). The IHSS is thanked for the Travel Award (IHSS-TRA-2025-6) that supported a research stay of F.J. MorenoRacero at the University of O’Higgins.
RkJQdWJsaXNoZXIy NDA4Mjc=