Greenhouse cherry tomatoes are valued for their flavor, nutrition, and high market demand, but producing more fruit sustainably remains a challenge. One major obstacle is phosphorus, an essential nutrient that plants need for root development, flowering, and fruit production. Although greenhouse soils often contain large amounts of phosphorus from repeated fertilizer use, much of it becomes locked in forms that plants cannot easily absorb.
Now, researchers have found a promising biological strategy: combine biochar with phosphorus-mobilizing Bacillus bacteria. In a new study published in Biochar, the team reports that a biochar-Bacillus consortium improved phosphorus availability in soil, reshaped the root-zone microbial community, strengthened root architecture, promoted fruit-cluster branching, and ultimately increased cherry tomato yield.
"Our goal was to turn the soil's existing phosphorus reserves into a more available nutrient source for crops, rather than relying only on continued fertilizer input," said corresponding author Yu Lan. "By using biochar as a carrier for beneficial Bacillus strains, we created a more favorable rhizosphere environment that supports both microbial activity and plant growth."
The researchers tested four treatments in a greenhouse cherry tomato system: an untreated control, biochar alone, Bacillus liquid inoculant alone, and the combined biochar-Bacillus treatment. The biochar was produced from rice husk and used as a porous habitat and carrier for three Bacillus strains known for their phosphorus-solubilizing potential.
The combined treatment produced the strongest effects. Compared with the control, the biochar-Bacillus consortium increased rhizosphere available phosphorus by 10.16%, microbial biomass phosphorus by 174.76%, and alkaline phosphatase activity by 68.52%. Alkaline phosphatase is an enzyme closely linked to microbial phosphorus cycling, meaning the treatment helped activate biological pathways that release usable phosphorus from soil reserves.
The benefits extended from soil to plant. Cherry tomato plants treated with the consortium developed larger and more active root systems, including increases in root length, surface area, volume, and tip number. These root improvements helped plants acquire more phosphorus, with phosphorus uptake efficiency rising by 19.99% compared with the control.
The study also revealed an important link between soil biology and reproductive growth. The biochar-Bacillus treatment increased the proportion of fruit-bearing lateral branches, improving inflorescence architecture. Although individual fruits were slightly lighter, the number of fruits per plant rose substantially, leading to an overall 23.53% increase in yield.
Microbial analysis showed that the consortium enriched beneficial bacterial groups, including Bacillus and Sphingomonas, while shifting the soil community toward a structure more favorable for phosphorus mobilization and plant growth. Structural equation modeling further suggested that microbial biomass, enzyme activity, root traits, and fruit-cluster branching worked together to drive yield improvement.
"This study highlights a soil-plant-microbe pathway for improving crop productivity," said corresponding author Dianyun Cao. "The findings suggest that biochar-based microbial amendments may help greenhouse growers use phosphorus more efficiently while supporting sustainable intensification."
The authors note that more research is needed to understand how improved phosphorus nutrition influences the developmental biology of tomato inflorescences. Still, the results provide a practical and biologically grounded approach for improving greenhouse tomato production using a combined soil amendment that works with, rather than against, the soil microbiome.
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Journal Reference: Liu, S., Shi, Y., Zhang, A. et al. Synergistic biochar‑Bacillus consortium enhances phosphorus availability, root architecture, and inflorescence development in greenhouse cherry tomato. Biochar 8, 66 (2026).
https://doi.org/10.1007/s42773-026-00586-z
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About Biochar
Biochar (e-ISSN: 2524-7867) is the first journal dedicated exclusively to biochar research, spanning agronomy, environmental science, and materials science. It publishes original studies on biochar production, processing, and applications—such as bioenergy, environmental remediation, soil enhancement, climate mitigation, water treatment, and sustainability analysis. The journal serves as an innovative and professional platform for global researchers to share advances in this rapidly expanding field.
