Objective The aims were to investigate the interaction characteristics between wheat and soil microbes under a wheat-maize rotation system during the early stage of soil reclamation, particularly focusing on the effects of different soil organic matter contents on these interactions.

Method The utilized cropland subsoil was sued to established three soil organic matter levels (low, L; medium, M; high, H) by adding organic fertilizers. A wheat-maize rotation experiment was conducted, and soil bacterial community diversity, network structure, and assembly drivers were measured before wheat sowing and after wheat harvest.

Result The results indicated that variations in soil organic matter did not significantly affect soil bacterial α diversity. However, after wheat harvest, soil organic matter content significantly influenced bacterial β diversity. Before wheat sowing, M and H treatments exhibited higher abundances of plant growth-promoting bacteria, including Noviherbaspirillum, Phenylobacterium, Brevundimonas, Devosia, Bacillus, and Pseudaminobacter. Network analysis revealed that soils with higher organic matter content exhibited relatively more complex network structures, characterized by higher numbers of nodes, connections and average path lengths. Wheat planting significantly impacted soil bacterial network features, resulting in a notable decrease in the number of nodes, connections, average degree, and average clustering coefficient after wheat harvest. Deterministic processes dominated the assembly of soil bacterial communities. Before the wheat sowing, variable selection accounted for 69%, diffusion limitation for 28%, and drift for 3%. After the wheat harvest, variable selection accounted for 63%, diffusion limitation for 5%, homogeneous diffusion for 5%, and drift for 27%.

Conclusion These findings conclusively demonstrated that wheat planting under a wheat-maize rotation system significantly influences soil bacterial community composition, network structural characteristics, and community assembly drivers, with specific effects modulated by soil organic matter content. Increasing soil organic matter content enhances the abundance of plant growth-promoting bacteria and improves bacterial network stability.