Sodicity Thresholds Alter Biodiversity-Multifunctionality Relationships Through Fungal Dominance and Microbial...

Area of Science:

• Soil Science
• Ecology
• Microbiology

Background:

• Increasing soil sodicity poses a significant threat to global agroecosystems.
• The precise role of exchangeable sodium percentage (ESP) in modulating biodiversity-ecosystem multifunctionality (BEF) relationships remains unclear.

Purpose of the Study:

• To investigate how ESP influences BEF relationships across diverse Chinese landscapes.
• To identify critical ESP thresholds that trigger significant shifts in ecosystem structure and function.
• To elucidate the mechanistic links between microbial traits, strategies, and soil multifunctionality under varying sodicity.

Main Methods:

• Surveyed 378 soil samples from paired saline-sodic lands and farmlands across China.
• Utilized random forest models to identify key abiotic predictors of soil multifunctionality.
• Employed metagenomic and trait-based analyses to characterize microbial communities and their functional strategies.

Main Results:

• ESP was the primary abiotic predictor of soil multifunctionality, with critical thresholds at ~13% for cropped systems and ~44% for natural saline-sodic habitats.
• ESP-driven shifts altered BEF relationships and promoted fungal dominance in microbial communities.
• Microbial strategies (nutrient recycling, metabolic capacity) differentially impacted multifunctionality depending on land use (farmland vs. saline-sodic).

Conclusions:

• ESP acts as a crucial regulator of BEF relationships and microbial adaptations in soils.
• Understanding ESP thresholds and microbial strategies is vital for managing saline-sodic soils.
• This research provides mechanistic insights for sustainable agroecosystem management under climate change.