Linkage between microbial functional genes and net N mineralisation in forest soils along an elevational gradient

Summary

This metagenomic study characterised the microbial basis of net nitrogen mineralisation in forest soils across an elevational gradient (1503–3182 m). The authors found that N mineralisation followed a unimodal pattern with elevation, peaking at mid-high elevation, and identified keystone functional genes in Cyanobacteria, Acidobacteria and Planctomycetes as predominant determinants. Soil substrate composition and environmental conditions (temperature, moisture) emerged as major regulatory factors influencing microbial community assembly and functional gene abundance, thereby modulating soil N cycling.

Regional applicability

The study was conducted in forest soils at high elevations; direct applicability to United Kingdom lowland agricultural soils is limited. However, the mechanistic insights into how microbial functional genes regulate N mineralisation and how soil temperature, moisture, and substrate availability drive these processes may inform UK soil management strategies for improving N cycling efficiency in upland grassland and forestry systems.

Key measures

Net N mineralisation rate (mg kg⁻¹ d⁻¹); abundance of microbial functional genes (denitrification and ammonia assimilation pathways); soil ammonium nitrogen, nitrite nitrogen, organic carbon, C:N ratio, temperature, and moisture; microbial community composition by metagenomic sequencing

Outcomes reported

The study identified soil microbial functional genes encoding N-cycling enzymes and measured net N mineralisation rates across five forest sites at different elevations. It established correlations between specific microbial taxa, their functional genes, and N mineralisation rates, and identified soil substrate and environmental factors as key regulatory drivers.

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