Consecutive melon monocropping is associated with microbial community homogenization and reduced bacterial network...

Area of Science:

• Agricultural Science
• Soil Science
• Microbiology

Background:

• Monocropping disrupts soil microbial communities, impacting soil health and crop yields.
• Bio-organic fertilizers are used to mitigate monocropping's negative effects, but their long-term impacts on soil microbiomes are unclear.

Purpose of the Study:

• To investigate the long-term effects of monocropping and Bacillus subtilis-based bio-organic fertilizer on soil microbial communities and ecosystem functions.
• To assess how varying monocropping durations (1, 3, and 5 years) influence soil microbial structure and function.

Main Methods:

• Collected 72 soil samples from Hami melon fields with 1, 3, and 5 years of monocropping.
• Analyzed bacterial and fungal community structure using high-throughput sequencing.
• Evaluated soil ecosystem functions including carbon degradation, nutrient cycling, carbon storage, and physical structure.

Main Results:

• Prolonged monocropping reduced fungal pathogens and increased beneficial bacteria, but led to microbial homogenization (reduced diversity and beta-dispersion).
• Bacterial co-occurrence networks showed decreased complexity with longer monocropping durations.
• Carbon degradation peaked at 3 years of monocropping; other functions remained stable.

Conclusions:

• Long-term monocropping with Bacillus subtilis bio-organic fertilizer promotes microbial homogenization and simplifies bacterial networks.
• Despite microbial shifts, key soil ecosystem functions largely remain stable under prolonged monocropping conditions.