Arable soil nitrogen dynamics reflect organic inputs via the extended composite phenotype.

Area of Science:

• Agricultural Science
• Soil Science
• Microbiology

Background:

• Food security depends on resilient agriculture, requiring efficient nutrient and water use and reduced emissions.
• Soil nitrogen and carbon metabolism, soil structure, and microbial nitrogen transformations are key to resilient agricultural systems.
• Organic matter's role in reducing nitrous oxide emissions and enhancing soil resilience needs mechanistic understanding.

Purpose of the Study:

• To decode the influence of organic matter on arable soil nitrogen transformations.
• To link soil structural parameters with metagenomic data for a mechanistic explanation.
• To understand why organic matter reduces nitrous oxide losses and supports system resilience.

Main Methods:

• Integration of metagenomic data with soil structural parameters.
• Analysis of nitrogen transformations at microbial-relevant scales.
• Investigating the relationship between organic carbon, soil-connected porosity, and flow rates.

Main Results:

• The influence of organic matter on soil nitrogen transformations can be explained by integrating metagenomic data and soil structure.
• Organic matter reduces nitrous oxide (N2O) losses and supports agricultural system resilience.
• A relationship exists between organic carbon, soil-connected porosity, and microbial flow rates.

Conclusions:

• The study provides a mechanistic explanation for organic matter's benefits in soil nitrogen cycling.
• Increased nutrient-use efficiency may be achievable with lower organic carbon stocks than previously thought.
• Optimizing soil structure and organic matter can enhance agricultural resilience and reduce environmental impact.