Wood-derived topsoil cover positively influences the diversity and activity of tomato plant rhizobacteria

Worsening water shortages due to climate change have underscored the need for sustainable agricultural practices, including mulching, to restore soil moisture and health. Environmental concerns associated with plastic mulching materials in agriculture have prompted the adoption of biodegradable alternatives. Topsoil cover (TSC), developed through the valorization of wood industry by-products and xanthan gum, offers a sustainable solution. Indigenous microbiomes, predominantly Proteobacteria (e.g., Pseudomonas spp.), Firmicutes (e.g., Staphylococcus spp.), and Aspergillus spp., can biodegrade TSC under controlled condition. Germination tests confirm its effectiveness in weed control. A greenhouse experiment using tomato (Solanum lycopersicum) demonstrated that TSC enhances shoot and root length by 50 and 100%–160% and overall biomass by 30%–50%, without altering rhizosphere soil physicochemical properties or microbial community structure. Additionally, the reversible effect of TSC can enhance the early soil nitrogen pool by 20% through microbial interactions. It also increases soil microbial metabolic diversity, highlighting its potential for agricultural use. Our findings establish TSC as an innovative product that closes the loop on timber industry waste while enhancing soil fertility, promoting plant health, and enabling medium-term carbon storage in wood.