Long-term herbicide residues affect soil multifunctionality and the soil microbial community

Area of Science:

• Soil science
• Environmental chemistry
• Microbiology

Background:

• Extensive herbicide use poses risks to soil ecosystems and agricultural sustainability.
• The long-term effects of herbicide residues on soil multifunctionality and microbial communities are not well understood.

Purpose of the Study:

• To investigate the relationship between residual herbicide concentrations, soil multifunctionality, and soil microbial communities in black soil.
• To understand how herbicide residues affect key soil microbial genera and overall soil health.

Main Methods:

• Analysis of 62 black soil samples from northeastern China.
• Quantification of total residual herbicide concentrations.
• Assessment of soil multifunctionality and microbial community structure.
• Structural equation modeling (SEM) to determine causal relationships.

Main Results:

• Soil multifunctionality showed an inverted U-shaped response to herbicide residues, peaking at ~310 μg/kg.
• Microbial richness decreased significantly in soils with high herbicide concentrations (>310 μg/kg).
• Abundances of specific keystone genera (e.g., norank_f_Acetobacteraceae) correlated with soil multifunctionality and were affected by herbicide residues.

Conclusions:

• Long-term herbicide residues significantly impact agricultural black soil multifunctionality.
• Low herbicide concentrations may stimulate soil functions, while high concentrations are inhibitory.
• Herbicide residues influence soil multifunctionality primarily by altering keystone microbial communities, necessitating judicious herbicide application for soil health.