Action: Add fresh peat to peatland (before planting)
Key messagesRead our guidance on Key messages before continuing
- One study evaluated the effects, on peatland vegetation, of adding fresh peat before planting peatland plants. The study was in a bog.
- Cover (1 study): One replicated, controlled, before-and-after study in a bog New Zealand reported that plots amended with fine peat supported higher cover of two sown plant species than the original (tilled) bog surface. However, for one species fertilization cancelled out this effect.
Fresh ground or ‘milled’ peat could be added to the surface of peatlands before introducing vegetation. The fresh peat could provide a better substrate for plant growth: covering any dry crust on the degraded peatland and providing a fine substrate for rooting. Added peat can also be used to smooth over the peatland surface (removing raised areas or depressions that might be too dry or wet for peatland plant growth), modify the water level to which introduced vegetation is exposed (e.g. to avoid winter flooding), or create a buffer between polluted peat and the surface where plants are introduced (Rezanezhad et al. 2012). Finally, the fresh peat may contain extra nutrients to give plants an initial boost.
Key peatland types where this action may be appropriate: bogs, fens/fen meadows, tropical peat swamps.
Rezanezhad F., Andersen R., Pouliot R., Price J.S., Rochefort L. & Graf M.D. (2012) How fen vegetation structure affects the transport of oil sands process-affected waters. Wetlands, 32, 557–570.
Supporting evidence from individual studies
A replicated, controlled, before-and-after study in 1998–2000 in a historically mined raised bog in New Zealand (Schipper et al. 2002) reported that amending plots with fine peat allowed greater cover of two sown species to develop, although for one species only in the absence of fertilizer. These results are not based on tests of statistical significance. After 810 days, plots amended with peat before sowing manuka Leptospermum scoparium seeds had 99–100% manuka cover, compared to only 1–68% manuka cover in plots not amended with peat. Plots amended with peat before sowing bamboo rush Sporadanthus ferrugineus seeds developed 0–32% rush cover (0–6% when fertilized; 32% when not fertilized), compared to 0–11% when not amended with peat. In March 1998, forty-eight 25 m2 plots were sown: 24 with manuka and 24 with bamboo rush. For each plant species, eight plots were on a 30 cm layer of fresh fine peat and 16 directly on the existing bare peat (but note this was also tilled). Some plots were fertilized with phosphorous, nitrogen or both. In June 2000, canopy cover was visually estimated in each plot. This study also reported the effect of fertilization in unsown plots (see original paper).