A bio-based pesticide sustained release system constructed from cellulose-chitosan hydrogel: Promoting seed germination and providing protection

Water is essential for crop growth, particularly during the seed germination stage. This study proposes a novel strategy utilizing a natural bio-based hydrogel to enhance soil water retention and improve the hydration capacity for seeds. A hydrogel (CMC-Na/HACC/FeCl 3 ), synthesized from sodium carboxymethyl cellulose (CMC Na) and chitosan quaternary ammonium salt (HACC) via ferric chloride (FeCl 3 ), has the advantages of high stability and low cytotoxicity. Upon water absorption, the swelling degree of CMC-Na/HACC/FeCl 3 exceeds 20 g/g, providing sufficient moisture for plant growth. The experimental results showed that CMC-Na/HACC/FeCl 3 could significantly increase the seed germination rate compared with the traditional soil, and the germination rate could be up to 75 %, and the germination time, the length of germ and the length of the embryonic axis were significantly improved. In addition, in this study, the plant extracted insecticide matrine (MT) was added into the hydrogel system to form CMC-Na/HACC/FeCl 3 /MT. The results of the study showed that MT could be gradually released from the hydrogel, and the release time could last for 21 days. The hydrogel provided moisture to the seeds while creating a barrier against pest invasion and showed significant antibacterial effects. Both CMC-Na/HACC/FeCl 3 and CMC-Na/HACC/FeCl 3 /MT are anticipated to be valuable in agricultural production due to their excellent properties, which contribute to improving soil composition and minimizing resource waste and environmental pollution.