Silica modified copper-based alginate/chitosan hybrid hydrogel to control soil fumigant release, reduce emission and enhance bioactivity

Soil fumigant has been extensively used for excellent efficacy on soil-borne diseases. However, rapid emission and insufficient effective duration typically limit its application. In this study, hybrid silica/polysaccharide hydrogel was proposed (SIL/Cu/DMDS) by emulsion-gelation method to encapsulate dimethyl disulfide (DMDS). The orthogonal study was used to optimize the preparation parameters for LC and EE of SIL/Cu/DMDS, which was 10.39 % and 71.05 %, respectively. Compared with silica, the time for 90 % of the total emissions was extended by 4.36 times. The hydrogel possessed a longer persistent duration and the degradation half-life of DMDS was 3.47 times greater than that of silica alone. Moreover, the electrostatic interaction between abundant groups of polysaccharide hydrogel bestowed DMDS with pH-triggered release behavior. Additionally, SIL/Cu/DMDS had excellent water holding and water retention capacity. The bioactivity of the hydrogel was 58.1 % higher than that of DMDS TC due to the strong synergistic effect between DMDS and the carriers (chitosan and Cu2+), and showed obvious biosafety to cucumber seeds. This study seeks to provide a potential approach to develop hybrid polysaccharide hydrogel to control soil fumigants release, reduce emission and enhance bioactivity in plant protection.