ADSORPTION, DEGRADATION AND RESIDUE ANALYSIS OF AGROCHEMICALS IN AGRICULTURAL SOILS

Abstract

In modern agriculture agrochemicals are applied to increase crop productivity, manage pest and weeds, and prevent plant diseases. Due to repeated use however soil contamination, persistence of residues, ecological toxicity, groundwater pollution, and transfer into the food chain has become of great concern. The present study discusses the adsorption, degradation, mobility, residue analysis, risk assessment and sustainable management of agrochemicals in agricultural soils. The review brings together recent works on the behavior of agrochemicals in soil systems, highlighting physicochemical properties, adsorption desorption interactions, degradation reaction pathways, environmental fate and degradation, analytical methods for detection, and remediation strategies. The key processes are discussed, including microbial degradation, chemical transformation, photodegradation, leaching, plant uptake and bound residue formation. Chemical properties including solubility, polarity, hydrophobicity, partition coefficient, molecular structure, type of agrochemical formulation and degradation rate in the soil (half-life) control the fate of agrochemicals in soil. The mobility and bioavailability of residues are controlled by adsorption, their persistence and conversion into metabolites by degradation. Strongly bound and non-extractable residues can serve as long term contamination reservoirs. Soil-residue management for sustainability needs to be integrated with monitoring, risk-based regulation, bioremediation, phytoremediation, organic amendments, biochar application, precision agriculture, and integrated pest management to minimize agrochemical persistence and mitigate effects on soil, water, crops, and human health.