Synergistic effects of biochar-immobilized Stenotrophomonas acidaminiphila on potassium availability and ryegrass productivity in purplish soil

Tingrui Zhang ¹, Wei Wei ², Jinchuan Xie ²

⁰College of Land Science and Technology, China Agricultural University, Beijing, 100193, China; College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.

Journal of Environmental Management +

|

November 27, 2025

View abstract on PubMed

Summary

Biochar-immobilized potassium-solubilizing bacteria (KSB) enhance plant growth and potassium uptake in diverse soils. This sustainable biofertilizer improves soil fertility by mobilizing and stabilizing soil potassium, offering an eco-friendly alternative to mineral fertilizers.

Area Of Science

Soil Science
Microbiology
Agronomy
Environmental Science

Background

Microbial potassium (K) solubilization offers an eco-friendly alternative to conventional K fertilizers.
Bacterial survival and effectiveness in soil environments are critical limitations for microbial K solubilization.

Purpose Of The Study

To evaluate Stenotrophomonas acidaminiphila Ab27 as a potassium-solubilizing bacterium (KSB).
To assess maize straw biochar (MSC500°C) as a carrier for KSB immobilization.
To investigate the efficacy of biochar-immobilized KSB (KMSC) on plant growth and soil K dynamics in purplish soils.

Main Methods

Identification and characterization of Stenotrophomonas acidaminiphila Ab27 as a KSB.
Pyrolysis of maize straw at 500°C to produce biochar (MSC500°C) and evaluation of its properties.
Immobilization of Ab27 onto MSC500°C to create KMSC.
Pot experiments using KMSC, biochar, or bacteria alone on ryegrass in acid, neutral, and calcareous purplish soils.
Analysis of ryegrass biomass, K uptake, and soil K fractions.

Main Results

Stenotrophomonas acidaminiphila Ab27 demonstrated efficient K solubilization (22.12 μg mL⁻¹).
MSC500°C exhibited optimal properties (moderate aromaticity, pore structure, functional groups) for bacterial immobilization.
KMSC significantly increased ryegrass biomass (up to 163.30%) and K uptake (up to 558.95%) compared to individual treatments.
KMSC promoted mobilization of readily available K (up to 13.38-folds) and stabilized slowly available K pools.
A comprehensive evaluation index confirmed KMSC's effectiveness across diverse soil types.

Conclusions

Biochar-immobilized Stenotrophomonas acidaminiphila Ab27 (KMSC) is a highly effective biofertilizer for enhancing plant growth and K uptake.
KMSC improves soil K availability and long-term fertility by mobilizing and stabilizing soil K pools.
Biochar-microbe composites represent a promising strategy for sustainable nutrient management and an alternative to mineral K fertilizers.

Keywords:

Biochar feedstock Comprehensive evaluation Potassium dynamics Potassium-solubilizing bacteria

Related Concept Videos

Bioremediation

Bioremediation is the use of prokaryotes, fungi, or plants to remove pollutants from the environment. This process has been used to remove harmful toxins in groundwater as a byproduct of agricultural run-off and also to clean up oil spills.

Agricultural Bioremediation

Bioremediation is a useful process in which microbes and bacteria are used to remove toxins and pollutants from the environment. In agricultural practices, the use of fertilizers and pesticides can result in leaching of...