Clomazone improves the interactions between soil microbes and affects C and N cycling functions

Area of Science:

• Soil microbiology
• Environmental science
• Agrochemistry

Background:

• Clomazone is a herbicide commonly used in soybean cultivation.
• Previous research indicated clomazone impacts soil Proteobacteria and Nitrospirae abundances and urease activity, affecting nitrogen cycling.
• The effects of clomazone on the co-occurrence patterns of soil microbial species and functions remained largely unknown.

Purpose of the Study:

• To investigate the dynamics of soil microorganisms in response to clomazone application.
• To understand how clomazone affects bacterial and fungal community structures and interactions.
• To assess the impact of clomazone on soil ecosystem functions related to nutrient cycling.

Main Methods:

• A 3-month greenhouse experiment was conducted using three doses of clomazone (T1, T10, T100).
• Bacterial and fungal abundances were quantified over time.
• Community structures were analyzed using network analysis.
• Functional groups associated with nutrient cycling and trophic types were assessed.

Main Results:

• Clomazone significantly increased bacterial abundance and led to more complex, highly connected microbial communities.
• Fungal abundance showed varied responses, with stimulation at lower doses and inhibition at higher doses.
• Denitrification and hydrogen oxidation functional groups decreased, while photoheterotrophy and carbon cycling functions (fermentation, cellulolysis) were enhanced.
• The half-life of clomazone in soil ranged from 40.1 to 93.5 days.

Conclusions:

• Clomazone significantly alters soil microbial community structure and function, with dose-dependent effects.
• Herbicide application influences nitrogen and carbon cycling pathways, with implications for soil health.
• Understanding these microbial shifts is crucial for sustainable herbicide use in agriculture.