Enhancing Biological Nitrogen Fixation Through Diverse Pasture Swards
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Date
2025-09
Open Access Location
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI (Basel, Switzerland)
Rights
(c) 2025 The Author/s
CC BY 4.0
CC BY 4.0
Abstract
Regenerative agricultural practices emphasize the use of diverse pasture species within sustainable agriculture production systems. The inclusion of a range of legume species in diverse pasture swards is likely to increase biological N fixation (BNF) across seasons, reducing the system’s reliance on synthetic N inputs. The present field study aims to quantify BNF in selected legume species within diverse pasture (combining 9 species) and standard pastures (ryegrass and clover combination) and assess their performance to identify the potential for improving N supply while maintaining year-round pasture quality. A year-round seasonal BNF was assessed by evaluating soil N status, nodulation patterns, plant composition, and conducting <sup>15</sup>N natural abundance studies. The results revealed that the diverse pasture sward produced 5.4% more dry matter compared to the standard pasture, while soil mineral N (NO<inf>3</inf><sup>−</sup>, NH<inf>4</inf><sup>+</sup>) remained statistically similar between the two treatments. Nitrogen yield was 9.3% higher in the diverse pasture than in the standard pasture. <sup>15</sup>N natural abundance analysis assessment revealed no substantial variation in BNF rates across treatments throughout the study. However, in contrast to standard pasture, the BNF rate in diverse pasture experienced a 3-fold increase from winter to summer, while the standard pasture exhibited a 1.5-fold increase. In both pasture systems, BNF increased with clover proportion up to 30%, indicating optimal fixation at moderate clover levels. The findings underscore the potential of diverse pastures when strategically managed to enhance seasonal BNF while sustaining pasture productivity.
Description
Keywords
biological nitrogen fixation; diverse pasture; 15N natural abundance; nitrogen difference method; regenerative agriculture, biological nitrogen fixation, diverse pasture, 15N natural abundance, nitrogen difference method, regenerative agriculture
Citation
Sutharsan R, Jeyakumar P, Burkitt L, Matse DT, Dhanuskodi R, Hanly J, Donaghy DJ. (2025). Enhancing Biological Nitrogen Fixation Through Diverse Pasture Swards. Plants. 14. 17.