Bacterial Resilience and Community Shifts Under 11 Draining-Flooding Cycles in Rice Soils

Area of Science:

• Agricultural Science
• Microbiology
• Soil Science

Background:

• Flooded rice cultivation is crucial globally, yet alters soil properties and nutrient availability.
• Understanding microbial responses to water management is key for sustainable agriculture.

Purpose of the Study:

• Investigate bacterial community dynamics in rice soils under repeated draining and flooding.
• Assess microbial resilience and shifts in community structure and function over time.

Main Methods:

• Field study in Rio Grande do Sul, Brazil, with 11 draining/flooding cycles.
• Beta diversity analysis to track community changes.
• Functional prediction of microbial metabolic responses.

Main Results:

• Bacterial communities demonstrated resilience but shifted over 11 cycles, forming four distinct states.
• Shifts driven by taxa substitution, not diversity loss; notable changes in Acidobacteria, Proteobacteria, Chloroflexi, and Verrucomicrobia.
• Nitrification increased during drained periods; fermentation surged after the sixth cycle, linked to pH changes.

Conclusions:

• Repeated environmental disturbances reduce microbial resilience in rice soils.
• Bacterial community shifts, while significant, maintain ecosystem functioning.
• Findings offer insights into microbial adaptation for sustainable rice farming and soil management.