Biochar is a carbon rich material, produced through the thermal conversion of a wide range of feedstocks at elevated temperatures and under oxygen-deprived conditions¹. Considering its positive physical and chemical effects on soil properties, and due to its extensive pore structure, large surface area, and high adsorption capacity, significant research has been conducted on biochar use as controlled-release fertilizers (CRFs)^2,3. In the present work vineyard pruning’s were used to produce different biochars: (1) at industrial ovens from Ibero Massa Florestal (BIMF); (2) using a flow of CO₂ (BCO₂) in a laboratorial furnace; (3) and by pre-treating milled vineyard pruning’s with AlCl₃ and MgCl₂ solutions, and afterwards pyrolyzing in a laboratorial furnace. Following, the biochars capacity to adsorb nitrogen (N), phosphorous (P) and potassium (K) in function of the pH was investigated. The most promising biochar and most adequate pH value for N and P adsorption were selected for further optimizations, namely effect of adsorbent dosage, kinetic assays and adsorption isotherms. In contrast, K adsorption results across all biochars and pH values were not favourable, so no further optimizations were pursued. Langmuir model showed the best fit for the adsorption isotherms and the maximum Langmuir adsorption capacities corresponded to 10.4 mg N/g biochar for BIMF biochar and 12.7 mg P/g biochar for BMgCl₂. These results suggest that vineyard pruning’s, presently considered an undervalued residue, could be used for the production of an economically valuable product, following the principles of circular economy. Additionally, this study also suggests that CRFs prepared from vineyard pruning’s and possibly from other cellulosic agro-industrial residues could be used as a substitute for conventional fertilizers, which are associated with many environmental issues.