Optimizing flue-cured tobacco planting patterns: enhanced rhizosphere nutrient availability and microbial community...

Area of Science:

• Soil Science
• Microbiology
• Agronomy

Background:

• Continuous monoculture of flue-cured tobacco leads to soil degradation and microbial imbalances.
• Understanding how different cropping systems impact soil carbon (C) and nitrogen (N) metabolism is crucial for sustainable agriculture.

Purpose of the Study:

• To investigate the effects of different cropping patterns on soil health, microbial communities, and C/N metabolic functions in flue-cured tobacco cultivation.
• To compare tobacco monoculture, tobacco-maize rotation, tobacco-rice rotation, and tobacco-sweet potato intercropping systems.

Main Methods:

• A four-year field experiment was conducted.
• Evaluated soil physicochemical properties, enzyme activities, and microbial community composition using metagenomic sequencing.
• Analyzed microbial network interactions and the abundance of C and N cycling genes.

Main Results:

• Tobacco-rice rotation significantly improved soil properties (pH, organic matter) and boosted beneficial microbes (Pseudomonadota, Mucoromycota).
• Tobacco-rice rotation upregulated C-cycle and N-assimilation genes while suppressing denitrification.
• Tobacco-maize rotation showed mixed results, while tobacco-sweet potato intercropping negatively impacted microbial communities and suppressed C/N metabolism, promoting pathogens.

Conclusions:

• Cropping patterns differentially influence soil microbial communities and metabolic functions, impacting their effectiveness against continuous cropping challenges.
• Tobacco-rice rotation offers a sustainable solution by promoting efficient C/N cycling ('high assimilation, low denitrification') and enhancing soil health.
• The findings provide a framework for designing effective cropping systems to improve soil health and tobacco yield.