# Stabilizing Active Aluminum (Al3+) in Acidic Soils via Biochar-Induced Microbial Niches: Focusing on Denitrifier-Mediated Mechanisms, Efficiency, and Environmental Outcomes

## TL;DR

This study shows how biochar from rice husks can reduce toxic aluminum in acidic soils by creating conditions that help certain microbes neutralize it.

## Contribution

The study introduces a novel denitrifier-mediated mechanism using rice husk biochar for stabilizing Al3+ in acidic soils.

## Key findings

- Rice husk biochar achieved 22.1% Al3+ stabilization efficiency over 180 days.
- Biochar enriched denitrifiers like Thiobacillus and Arthrobacter, which helped neutralize soil pH and promote Al(OH)3 precipitation.
- The method offers a sustainable, low-cost solution for mitigating aluminum toxicity in acidic soils.

## Abstract

The pervasive toxicity of active aluminum (Al3+) in acidic red soils threatens agroecosystem sustainability, with conventional chemical stabilizers facing cost and secondary pollution constraints. This study evaluated rice husk/sawdust and their pyrolysis-derived biochar as stabilizers, focusing on microbial synergy. Results showed 3% rice husk biochar (RB) achieved 22.1 ± 1.1% stabilization efficiency within 180 days, outperforming sawdust biochar (12.1 ± 0.8%) and raw biomass. Biochar’s alkalinity and porosity created neutral niches, enriching denitrifiers (Thiobacillus, Arthrobacter, Thermomonas) that elevated pH, promoted Al(OH)3 precipitation, and enhanced oxygen-containing functional groups. This work valorizes agricultural waste for long-term Al3+ toxicity mitigation.