Biopolymer-based Encapsulation of Herbicides for Sustainable Weed Management: Materials, Mechanisms, Controlled Release and Field Perspectives

Abstract

Biopolymer-based encapsulation offers a formulation approach for modifying herbicide release, retention and environmental exposure while retaining weed-control activity. This review evaluates biodegradable biopolymers and biopolymer-based hybrid systems used for herbicide encapsulation, with an emphasis on carrier materials, formulation technologies, controlled-release mechanisms, kinetic modelling, field performance, environmental interactions and formulation optimisation. Chitosan, alginate, pectin, lignin and polyhydroxyalkanoates are prominent carrier materials, while layered double hydroxide–biopolymer hybrids provide an inorganic–organic alternative. Herbicide-specific evidence reported in the manuscript includes systems for atrazine, pretilachlor, trifluralin, glyphosate, 2,4-D and MCPA. These studies show that encapsulation can slow release and, in selected cases, retain herbicidal efficacy under laboratory or field conditions. However, a substantial proportion of the mechanistic evidence is derived from pharmaceutical, food and biomedical delivery systems and therefore provides transferable formulation principles rather than direct agricultural validation. Release behaviour depends on polymer chemistry, crosslinking, particle characteristics, swelling, diffusion, dissolution, erosion and environmental conditions. The principal constraints to wider adoption include scale-up, material variability, storage stability, formulation consistency, environmental fate, non-target assessment, economic feasibility and regulatory requirements. Overall, biopolymer encapsulation is promising for more controlled herbicide delivery, but broader agricultural value requires standardised characterisation, realistic soil and field validation, long-term environmental assessment and careful comparison with conventional formulations.