Soil Microbiome Restructuring Associated with Potassium Conversion Following Compound Bacillus Biofertilizer Application Under Continuous Cropping of Tomato
Year: 2026
Type: article
Abstract: Greenhouse tomato continuous cropping obstacles stem primarily from soil microecological imbalance and potassium fixation. While K-solubilizing bacteria are widely studied, how compound Bacillus biofertilizer drives cascading K bioactivation and absolute microbial community shifts under long-term protected tomato cropping remains unclear. Using spike-in absolute quantitative sequencing, this study offers novel insights into the linkage between compound Bacillus biofertilizer-driven microbial restructuring and soil K availability. A field trial was conducted in a 27-year continuous tomato cropping system with three fertilizer doses (0, 300, and 500 L/mu). We measured soil physicochemical properties, microbial community composition and metabolism, and root architecture and fruit yield and explored hypothesized path relationships to associate yield- and fruit-quality traits with soil K availability and root traits. The biofertilizer was associated with increased available K consistent with bioactivation rather than expanding the total K pool. At 500 L/mu, available K and microbial biomass K increased by 1383.96 mg/kg and 127.17 mg/kg, respectively, with unchanged total K, confirming that this pattern is consistent with activation of native potassium reserves. Soil macroaggregate content and stability improved with dose; the 500 L/mu treatment increased estimated bacterial 16S rRNA gene abundance by 21.6%, enriched putative beneficial taxa (Sphingomonas, Paenibacillus) and reduced Fusarium abundance. Potassium-solubilizing taxa were coupled with TCA cycle and organic acid synthesis. Single-fruit weight rose from 140.00 to 272.00 g. Structural equation modeling supported a hypothesized indirect yield-associated cascade: soil improvement → K transformation → root growth → yield. Compound Bacillus biofertilizer is consistent with a multi-level cascading regulation framework, providing a promising green strategy for mitigating continuous cropping obstacles.
Source: Microorganisms
Institution: Shenyang Agricultural University
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,258
OpenAlex ID: W7225806136