Clomazone influence soil microbial community and soil nitrogen cycling

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Clomazone is a widely used herbicide.
• Understanding its long-term impact on soil ecosystems is crucial.
• Soil microbial communities drive essential nitrogen (N) cycling functions.

Purpose of the Study:

• To investigate the long-term effects of clomazone on soil microbial communities.
• To assess the impact of clomazone on soil nitrogen (N) cycling functions.
• To determine the effects of different clomazone concentrations on soil microbial structure and function.

Main Methods:

• Indoor mesocosm experiment using two Chinese soils.
• Application of clomazone at 0.8, 8, and 80 mg kg⁻¹ dry weight.
• Analysis of soil microbial communities (16S and 18S rDNA sequencing) and N-cycling genes (nifH, amoA) over 90 days.

Main Results:

• Significant negative impacts observed only at the highest clomazone concentration (80 mg kg⁻¹).
• Bacterial diversity decreased, while fungal abundance increased after 60 days.
• Bacterial community structure was negatively impacted, with Sphingomonas and Arthrobacter identified as dominant species.
• Nitrate-N and ammonia-oxidizing bacteria increased initially, while N2-fixing bacteria were inhibited after 60 days.

Conclusions:

• High clomazone concentrations disrupt soil bacterial communities and impair nitrogen (N) cycling functions.
• Long-term exposure can lead to decreased bacterial diversity and inhibition of key microbial groups like N2-fixing bacteria.
• Further research is needed to understand the full ecological implications of clomazone in agricultural soils.