Soil microbial biodiversity promotes crop productivity and agro-ecosystem functioning in experimental microcosms

Area of Science:

• Soil ecology
• Agroecosystems
• Microbial ecology

Background:

• Soil biota are crucial for ecosystem functions and plant health.
• Land-use intensification threatens soil biodiversity, with unclear impacts on ecosystem multifunctionality.
• Understanding the interaction between soil biodiversity loss and agricultural practices like fertilization is essential.

Purpose of the Study:

• To experimentally assess how soil microbiome simplification affects soil multifunctionality and crop productivity.
• To investigate the interaction between soil biodiversity levels and mineral fertilizer application.
• To identify key soil microbial taxa indicative of ecosystem multifunctionality.

Main Methods:

• Experimental simplification of soil biological communities in microcosms.
• Application of mineral fertilizers to half of the microcosms.
• Measurement of soil alpha-diversity, ecosystem multifunctionality, and leek (Allium porrum) productivity and nitrogen uptake.
• Random forest analysis to identify indicator taxa.

Main Results:

• Significant reduction in soil bacterial and eukaryote richness, and removal of arbuscular mycorrhizal fungi.
• Soil community simplification decreased ecosystem multifunctionality, particularly plant productivity and nutrient retention.
• Ecosystem multifunctionality showed a positive correlation with soil biodiversity (R=0.79).
• Mineral fertilizer had minimal impact on multifunctionality but reduced leek nitrogen uptake from litter.
• Specific protists (Paraflabellula), Actinobacteria (Micolunatus), and Firmicutes (Bacillus) were identified as multifunctionality indicators.

Conclusions:

• Soil biodiversity is critical for maintaining ecosystem multifunctionality and essential services like food provision.
• Agroecosystem management should prioritize the preservation of soil bacterial and eukaryotic diversity.
• Fertilizer application may disrupt natural soil processes and organic nutrient acquisition.