Fertilization impacts microbiomes along the grassland trophic chain.

Area of Science:

• Agricultural Science
• Microbiology
• Ecology

Background:

• Intensive agricultural grassland management significantly alters soil properties and microbial communities.
• These microbial shifts can disrupt ecosystem health and functionality across multiple trophic levels.
• Understanding these cross-trophic interactions is crucial for ecosystem stability.

Purpose of the Study:

• To investigate the impact of different organic fertilizers on microbial communities in connected below- and above-ground grassland compartments.
• To determine how fertilization affects microbial composition and interactions across soil, root, and animal trophic levels.
• To assess the implications of these changes within the One Health framework.

Main Methods:

• Comparison of control grassland sites with sites treated with biogas digestate, cow/horse manure, and pig slurry.
• Utilized 16S rRNA amplicon sequencing for microbial community analysis.
• Conducted soil nutrient analysis to correlate with microbial shifts.

Main Results:

• Fertilization induced significant shifts in microbial composition, with compartment-dependent effects.
• Belowground compartments showed more pronounced changes, especially with pig slurry application.
• Overlapping bacterial genera across trophic levels suggest strong interactions, with pig slurry indirectly influencing communities via nutrient availability.

Conclusions:

• Fertilization effects extend across all trophic levels in grassland ecosystems.
• Pig slurry fertilization notably impacted microbial communities, particularly in animal compartments, with implications for One Health.
• Changes in nutrient availability are a key driver of fertilization-induced microbial shifts across trophic levels.