Biochar pH reduction using elemental sulfur and biological activation using compost or vermicompost

Area of Science:

• Soil science
• Environmental science
• Microbiology

Background:

• Biochar is a soil amendment with potential for arid lands.
• High pH of biochar can limit its application.
• Elemental sulfur and organic amendments can modify biochar properties.

Purpose of the Study:

• To evaluate elemental sulfur as a pH reducer for biochar.
• To assess the impact of co-applying compost or vermicompost.
• To determine the effects on biochar's chemical and microbial properties for arid land use.

Main Methods:

• Biochar was treated with elemental sulfur and co-amended with compost or vermicompost.
• Biochar pH, water-soluble elements, and substrate-induced respiration were measured.
• Bacterial community structure and diversity were analyzed using sequencing.

Main Results:

• Elemental sulfur significantly decreased biochar pH, with the greatest reduction (8.1 to 7.2) when combined with vermicompost.
• Water-soluble element concentrations increased, and respiration was stimulated, particularly with vermicompost.
• Bacterial diversity was altered, with compost/sulfur increasing the Shannon index and vermicompost enhancing evenness and equitability.

Conclusions:

• Integrating biochar with elemental sulfur and (vermi)compost is a viable strategy to manage alkalinity.
• This approach enhances biochar fertility and microbial activity, making it suitable for arid land applications.
• Elemental sulfur oxidation was linked to specific sulfur-oxidizing bacterial communities.