Add inorganic fertilizer: brackish/salt marshes

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects, on vegetation, of adding inorganic fertilizer to restore or create brackish/salt marshes. The study was in Canada.




  • Characteristic plant abundance (1 study): One replicated, paired, controlled, before-and-after study in salt-contaminated bogs in Canada found that adding fertilizer had no significant effect on cover of salt marsh vegetation, in unplanted plots, after one year.


About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, paired, controlled, before-and-after study in 2011–2012 in two salt-contaminated bogs in New Brunswick, Canada (Emond et al. 2016) found that fertilizing without introducing salt marsh vegetation had no significant effect on cover of salt marsh plants. After one year, cover of salt marsh plant species was very low in both fertilized bog plots (0% cover) and unfertilized bog plots (<0.1% cover). Methods: In summer 2011, sixteen 9-m2 plots were established (in four sets of four) on bare, salt-contaminated peat. Eight plots (two plots/block) were fertilized with rock phosphate, spread across the plot surface (50 g/m2) or placed in 49 holes/plot (9 g/hole). The other eight plots were not fertilized. Half of the fertilized and unfertilized plots were also limed, but no vegetation was introduced to any of the plots. In July 2012, cover of salt marsh plants (i.e. species present in a nearby salt marsh) was recorded in one 4-m2 quadrat/plot.

    Study and other actions tested
Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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Marsh and Swamp Conservation

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation
Marsh and Swamp Conservation

Marsh and Swamp Conservation - Published 2021

Marsh and Swamp Synopsis

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