Convergent-divergent succession of soil microbial communities driven by continuous maize cropping duration via heterogeneous selection processes

Yan-Liang Han¹Fang-Kun Yang^2,3Shu-Ping He¹Jia-Cheng Guo³Yue Zou¹Yun-Xu Shang³Peng Liu¹Peng-Yang Wang³Xing Wang⁴Ze-Ying Zhao³Juan Wang^1*Chun-Qing Miao^1*

• ¹Zhangye Academy of Agricultural Sciences, Zhangye, China
• ²Qinghai Normal University, Xining, Qinghai Province, China
• ³Lanzhou University, Lanzhou, Gansu Province, China
• ⁴Gansu Zhongkenyu Seed Industry Co., Ltd., Zhangye, China

The responsive alterations of soil microbial communities driven by continuous maize cropping (CC) and their assembly mechanisms constitute a fundamental scientific question for the sustainability of agricultural ecosystems. However, the assembly processes of microbial communities and their microecological effects under long-term CC remain poorly understood. We hypothesized that maize CC drives predictable shifts in microbial community assembly via increased deterministic selection. To address this, we established a short-to long-term CC gradient (1-25 years). We found that CC significantly altered microbial community structure, the relative abundance of dominant bacterial genera increased with CC years (CCY), whereas dominant fungal genera exhibited a declining trend. Co-occurrence network analysis revealed that long-term CC led to enhanced modularity in bacterial networks and a sharp decline in the proportion of negative correlations. Additionally, our findings reveal a transition from stochastic to heterogeneous selection-dominated processes over time, with microbial diversity metrics showing strong linear relationships with CC duration. This study elucidates how CC shapes convergent-divergent trajectories of microbial communities through heterogeneous selection pressures, providing theoretical support for guiding targeted soil microecological management.