Agricultural Jiaosu derived from Humulus scandens enhances tomato seedling growth through soil fertility improvement and microbial community reconstruction

• The Humulus scandens 100 × diluted AJ optimally promotes tomato growth, especially in root development. • AJ enhances soil available N/P, boosts cellulase/protease activity, and alleviates acidity, but has limited effect on K. • AJ reshapes soil microbiomes, increasing beneficial Proteobacteria and Ascomycota while reducing Basidiomycota. • Improved soil fertility and restructured microbial communities underpin AJ's growth-promoting mechanism. • AJ's raw material costs reduce by around 40% compared to chemical nutrient solutions.