Changes in Soil Microbial Activity, Bacterial Community Composition and Function in a Long-Term Continuous Soybean...

Area of Science:

• Soil microbiology
• Agricultural science
• Biogeochemistry

Background:

• Corn-soybean rotations and fertilization are key agricultural practices influencing soil health.
• While bacterial communities are studied, comprehensive analysis of microbial activity and function in long-term continuous soybean systems with corn insertion is limited.

Purpose of the Study:

• To investigate the impact of corn insertion (no corn, corn-soybean rotation, corn-corn-soybean rotation) and NPK fertilization on soil bacterial communities, microbial activity, and functional groups.
• To understand the interplay between crop rotation, fertilization, and soil microbial responses in a long-term soybean cropping system.

Main Methods:

• Long-term field experiment with different corn insertion strategies (Sm, CS, CCS) and fertilization regimes (no fertilization, NPK).
• High-throughput sequencing for bacterial community analysis and FaProTax for functional prediction.
• Measurement of soil respiration and extracellular enzyme activities (invertase, β-glucosidase, β-xylosidase, β-D-1,4-cellobiohydrolase) to assess microbial activity.

Main Results:

• Both corn insertion and NPK fertilization significantly altered soil bacterial community structure.
• Bacterial functional structure was primarily affected by corn insertion.
• NPK fertilizer enhanced soil carbon cycling enzyme activities and overall microbial activity, except for metabolic quotient (qCO2) under corn insertions.
• Corn insertions improved microbial activity, with exceptions in specific respiration ratios and qCO2.

Conclusions:

• The combination of crop rotation and fertilization profoundly influences soil microbial community composition and function.
• Soil microbial activity parameters are closely linked to the soil's capacity for aromatic compound degradation, predicting bacterial functional structure.
• This study provides comprehensive insights into the adaptive responses of soil microbial communities to agricultural management practices.