Pulse Brain · Growing Health Evidence Index
Tier 1 — Meta-analysis / systematic reviewPeer-reviewed

Organic amendments tighten nitrogen cycling in agricultural soils: a meta-analysis on gross nitrogen flux

Lauren C. Breza, A. Stuart Grandy

Frontiers in Agronomy · 2025

Read source ↗ All evidence

Summary

This meta-analysis synthesises peer-reviewed studies employing ¹⁵N pool dilution methods to quantify how organic and synthetic soil amendments affect nitrogen transformation rates in agroecosystems. The findings indicate that crop residue amendments stimulate substantially higher mineralisation and immobilisation rates than synthetic or manure amendments, and uniquely enhance ammonium pool size, suggesting a tighter coupling of carbon and nitrogen cycles that promotes more efficient soil nitrogen recycling.

Regional applicability

The study is a global meta-analysis synthesising data from multiple agroecosystems and therefore potentially transferable to United Kingdom farming conditions; however, the abstract does not specify whether UK studies were included in the analysis. The implications for UK arable and mixed farming systems would depend on the representativeness of the underlying datasets and whether soil type, climate, and management practices are comparable.

Key measures

Gross nitrogen mineralization rates, immobilisation rates, nitrification rates, ammonium (NH₄⁺) pool size, carbon:nitrogen ratios of amendments

Outcomes reported

The study quantified nitrogen mineralization, immobilisation, and nitrification rates in response to organic (manure and crop residue) and synthetic soil amendments using ¹⁵N pool dilution methods. It measured changes in ammonium pool sizes and assessed how different amendment types affect the coupling of carbon and nitrogen cycles in agricultural soils.

Theme
Farming systems, soils & land use
Subject
Soil fertility & nutrient management
Study type
Meta-analysis
Study design
Meta-analysis
Source type
Peer-reviewed study
Status
Published
Geography
Global
System type
Laboratory / in vitro
DOI
10.3389/fagro.2025.1472749
Catalogue ID
SNmomgxtr7-mb5fin

Topic tags

Pulse AI · ask about this record

Dig deeper with Pulse AI.

Pulse AI has read the whole catalogue. Ask about this record, its theme, or how the findings apply to UK farming and policy — every answer cites the underlying studies.