The influence of earthworm casts on Atrazine microbial degradation performance and pathway in black soil, Northeast China Raw sequence reads
The atrazine (ATR) is extensively used in dryland crops like corn and sorghum in black soil region of Northeast China, posing ecological risks due to toxic metabolites. Earthworm cast are known for soil organic pollution remediation but their role in pesticide degradation in black soil remains understudied. This study utilized high-throughput sequencing, liquid chromatography, mass spectrometry, and gradient analysis (RDA) to assess earthworm cast' influence on atrazine microbial degradation pathways. Although earthworm cast didn't significantly boost atrazine removal, they notably aided in primary metabolite degradation, hydroxyatrazine (HYA), deisopropylatrazine (DIA), and deethylatrazine (DEA), reducing their content by 38.67%. They also altered the soil microbial community structure, favoring atrazine-degrading bacteria like Proteobacteria, Firmicutes, and Actinobacteria phyla. Five deep degradation products were identified in earthworm casting treatments. Atrazine degradation occurred via dechlorination, dealkylation, and deamination pathways mainly by Nocardioidacea, Streptomycetaceae, Bacillaceae, Sphingomonadaceae, Comamonadaceae and Nitrososphaeraceae families. pH and available nitrogen (AN) influenced microbial community structure and atrazine degradation, correlating with earthworm casting application rates. Future black soil remediation should optimize application rates based on atrazine content and soil properties.