Abstract

FROM HERBICIDE POLLUTION TO SOIL RECOVERY: MICROBIAL BIODEGRADATION AND COST-EFFECTIVE CONSORTIA FOR RESTORING AGRICULTURAL SOIL HEALTH

*Pamila Nahomi Selvam C., Chandrasehar G.

Abstract

Herbicides support reliable crop production, but repeated applications can leave residues and transformation products in the soil and water. These compounds may disrupt microorganisms that decompose organic matter, cycle nutrients, form soil aggregates, and support plant growth. This review examines microbial biodegradation as a practical and potentially affordable method for reducing herbicide residues while aiding in the recovery of agricultural soils. The discussion focuses on bacteria, fungi, indigenous microbial communities, and microbial consortia, with examples of atrazine, 2,4-dichlorophenoxyacetic acid, and glyphosate. Microbial processes include hydrolysis, oxidation, dehalogenation, phosphonate cleavage, and aromatic ring breakdown. Biostimulation, bioaugmentation, compost-assisted treatment, biopiling, slurry bioreactors, and rhizosphere-assisted remediation were compared. Particular attention is given to the cost advantages of using locally adapted microorganisms, low-cost organic amendments, in situ treatment, and consortia in which different members complete different steps in a degradation pathway. Important limitations include the poor bioavailability of aged residues, variable soil conditions, metabolite accumulation, weak survival of introduced strains, and difficulty in transferring laboratory results to working farms. Metagenomics, functional omics, synthetic biology, and controlled genome editing may improve treatment design; however, their use must remain subject to ecological and regulatory safeguards. Therefore, successful remediation should be measured by both chemical reduction and the recovery of microbial activity, nutrient cycling, plant–microbe partnerships, soil structure, and crop productivity.

Keywords: Agricultural soil; bioaugmentation; biodegradation; biostimulation; herbicide residues; microbial consortia; soil health.