Combined application of biochar and PGPB on crop growth and heavy metals accumulation: A meta-analysis

Shanshan Zhao ¹, Shuling Zhao ¹, Baiqun Wang ²

⁰State Key Laboratory of Soil and Water Conservation and Desertification Control, The Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi 712100, China; State Key Laboratory of Soil and Water Conservation and Desertification Control, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; University of Chinese Academy of Sciences, Beijing 100049, China.

Environmental Pollution (Barking, Essex : 1987) +

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June 9, 2025

View abstract on PubMed

Summary

Combining biochar and plant growth-promoting bacteria (PGPB) significantly boosts plant growth and reduces heavy metal pollution in soil and plants. This synergistic approach enhances nutrient uptake and mitigates lead (Pb) stress.

Area Of Science

Environmental Science
Soil Science
Plant Biology

Background

Heavy metal pollution poses a significant threat to soil health and plant productivity.
Biochar and plant growth-promoting bacteria (PGPB) are individually recognized for their potential in soil remediation and plant growth promotion.
The synergistic mechanisms underlying the combined application of biochar and PGPB remain insufficiently understood.

Purpose Of The Study

To quantitatively evaluate the effectiveness of co-applying biochar and PGPB in promoting plant growth.
To assess the impact of this combined treatment on remediating soil heavy metals pollution.
To elucidate the underlying mechanisms of their synergistic action in the soil-plant system.

Main Methods

A hierarchical meta-analysis was employed, synthesizing data from 237 datasets across 59 studies.
Quantitative evaluation of plant biomass, heavy metal concentrations in plants and soil, nutrient absorption, and soil enzyme activities.
Analysis of specific PGPB (e.g., Pseudomonas, Proteobacteria) and biochar combinations for optimal outcomes.

Main Results

Co-application significantly increased root (84%) and shoot (116%) biomass.
Reduced heavy metal concentrations in roots (33%), shoots (45%), and soil (44%).
Enhanced plant nutrient absorption, stimulated soil enzyme induction, and optimized rhizosphere metabolic functions.
Biochar and Pseudomonas combination excelled in biomass enhancement; Proteobacteria and biochar consortium showed greatest heavy metal reduction.
The combination demonstrated superior efficacy in mitigating lead (Pb) pollution stress.

Conclusions

The co-application of biochar and PGPB offers a powerful strategy for alleviating plant heavy metal stress and remediating contaminated soils.
This synergistic approach enhances plant growth, nutrient uptake, and soil health.
Specific microbial consortia and biochar types can be optimized for targeted remediation outcomes, providing a scientific basis for sustainable soil management.

Keywords:

Biochar Heavy metals Meta-analysis Plant growth-promoting bacteria Soil-plant system

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