The role of biochar in the restoration of salinized and organically contaminated soils subjected to ecological degradation

Abstract

Background and Aim. This review article aims to evaluate the impact of biochar on the physicochemical
and biological properties of salinized, sodic, and organically contaminated soils, as well as its role in improving crop productivity. The goal is to identify ways to enhance soil conditions through the use of biochar, increase the neutralization of pollutants, and effectively boost agricultural productivity.
Materials and Methods. Based on the data from the literature review, comparative studies were
conducted on the pyrolysis methods of biochar from various feedstocks (wood, lignocellulose, manure)
at temperatures of 450-600 °C, as well as the functionalization of some samples with Fe or O/N additives
and the application rates of biochar to soil (1-40 t/ha). Additionally, quantitative and comparative analyses were performed on soil pH, electrical conductivity (ECe), sodium indices (SAR, ESP), water holding capacity (WHC), cation exchange capacity (CEC), soil organic carbon (SOC), pollutant removal efficiency, and crop yield data.
Results. The biochar has been shown to reduce electrical conductivity (ECe) in saline soils by 7-30% and increase crop productivity by 20-32%. In sodic soils, ESP decreased by 15-25% and SAR by approximately 20%. In soils contaminated with organic pollutants, removal efficiencies of PAHs and
pesticides reached 70-90%, while petroleum hydrocarbons were reduced by 30-70%. Biochar improved
soil structure and enhanced microbial activity. Functionalized biochars demonstrated improved sorption
and catalytic properties, while application rate and incorporation depth were identified as key factors
influencing effectiveness.
Conclusion. The findings indicate that biochar is a multifunctional and sustainable tool for soil remediation. It regulates salinity and alkalinity, immobilizes organic contaminants, and enhances crop productivity. The results confirm the effectiveness of standardized biochar application methods and highlight its important role in sustainable agriculture and environmental restoration.