The efficient application of nitrogen fertilizers is of paramount importance in the agricultural industry. Urease inhibitor is one of the technologies utilized to increase the efficiency of fertilizers� application Allicin has been identified as potential urease bio-inhibitor but their application is deterred by its high volatility nature and thus necessitates the encapsulation process using an appropriate wall material to overcome the limitation. The main objective of this work is to study the slow release behavior and the inhibition effect of allicin incorporated in a chitosan/starch based biopolymer. The synthesized biopolymers were subjected to Fourier Transforms Infrared Spectroscopy (FTIR) analysis and the existence of molecular interactions between starch and chitosan cross linked by glutaraldehyde were observed. Synthesized biopolymers were evaluated for swelling behavior in distilled water. The slow nitrogen release behavior on soil of the biopolymers urea fertilizer with and without allicin were evaluated using UV-Visible Spectroscopy analysis. The results show that Chitosan/Starch/Urea/Allicin biopolymer displays slower nitrogen nutrient release behavior in soil than the biopolymer without allicin after 7 days of application. This demonstrate the efficient incorporation of allicin as urease inhibitor in a biopolymer to further extend the nutrient release of urea fertilizers for long-term plants. © 2019 Elsevier Ltd. All rights reserved.