Relationships between soil biodiversity and multifunctionality in croplands depend on salinity and organic matter

Soil salinization is a widespread environmental problem adversely impacting global food production. Increasing soil organic matter (SOM) could alleviate salt stress, but soil salinity and SOM have differing effects on microbial diversity and activities. We explored how the relationships between soil biodiversity and multifunctionality were altered by soil salinity and SOM. We collected soils from the wheat-maize cropping system in the North China Plain and categorized soils according to salinity and SOM. Soil functions related to carbon, nitrogen, phosphorus, and micronutrient processing were measured as metrics of soil multifunctionality (SMF) characterization. We found significant positive relationships between SMF and bacterial diversity but not fungal diversity in soils with high SOM (>15 mg/kg) and low EC (