Effects of Continuous Straw Returning on Soil Functional Microorganisms and Microbial Communities

Area of Science:

• Agricultural Science
• Soil Science
• Microbiology

Background:

• Paddy fields often face challenges with soil health and nutrient cycling.
• Straw returning is a common agricultural practice to improve soil fertility.
• Understanding the impact of straw returning duration on soil microbial communities is crucial.

Purpose of the Study:

• To investigate the effects of 1, 2, and 3 years of straw returning (SR1-SR3) on paddy soil enzymatic activity, microbial diversity, and straw decomposition.
• To identify key microbial groups and soil properties influencing these changes.

Main Methods:

• Analysis of soil enzymatic activity and straw decomposition rates.
• 16S rRNA gene sequencing for microbial community structure analysis.
• Random forest models to determine the contribution of microbial taxa to enzyme activities.

Main Results:

• Straw decomposition rates and cellulolytic bacteria populations increased with straw returning duration.
• Straw returning enhanced microbial diversity and influenced specific bacterial groups like Azotobacter and Nitrobacteria.
• Specific microbial taxa were identified as key contributors to various soil enzyme activities (peroxidase, phosphate monoesterase, urease, invertase).

Conclusions:

• Soil microbial community structure and function are significantly altered within two years of straw returning.
• The changes are driven by soil organic carbon, nitrogen, potassium, and pH.
• Extended straw returning promotes a healthier soil micro-ecological environment.