Long-term conservation tillage enhances microbial carbon use efficiency by altering multitrophic interactions in soil

Area of Science:

• Soil Ecology
• Microbial Ecology
• Biogeochemistry

Background:

• Microbial carbon use efficiency (CUE) is critical for soil carbon storage and the global carbon cycle.
• The impact of multitrophic interactions, particularly protistan predation, on soil microbial CUE under conservation tillage remains poorly understood.

Purpose of the Study:

• To investigate the regulation of soil microbial CUE and soil organic carbon (SOC) by multitrophic interactions under long-term tillage practices.
• To determine the role of the keystone ecological cluster in mediating these effects.

Main Methods:

• Long-term field experiment comparing conservation tillage (CT) with traditional tillage (control, CK) over 15 years.
• Analysis of soil microbial communities (fungal and protistan), microbial physiological traits (CUE, MGR, Rs, turnover), and SOC.
• Statistical analysis to assess correlations between biodiversity, microbial traits, and SOC.

Main Results:

• Conservation tillage (CT) significantly increased microbial CUE, turnover, and SOC compared to traditional tillage (CK).
• Tillage practices and soil depth significantly influenced fungal and protistan community structures.
• Soil biodiversity within the keystone cluster positively correlated with microbial physiological traits and SOC, with protistan richness being a key driver.

Conclusions:

• Top-down control by protists in the soil micro-food web significantly improves microbial CUE under conservation tillage.
• Findings support the application of protists in microbial engineering for conservation agriculture and enhanced soil carbon sequestration.