Paludiculture (Wet farming) is an emerging way of producing crops and resources on peat soils in a truly sustainable way. The benefit of this system is that it allows the peat to stay wet enabling it to store carbon and reduce greenhouse gas emissions [1] something that a conventional farming system cannot achieve on wetland soils.
As we learn about this wet farming system and suitable crops, the data will increase and knowledge will evolve. The information provided here is current and accurate at the time of writing and presented in good faith.
Sphagnum Moss
Economic reasons to grow Sphagnum Moss. Established healthy markets exist in the reptile, floristry sectors with sale values varying from around £500 and £200-£250 per m3 respectively [2]. Current estimates suggest up to 100,000 Cu metres of moss is needed to meet immediate demand. The horticulture sector has potential as a market for sphagnum biomass to be an alternative replacement for peat in growing media. The use and value as a peat alternative is dependent on the quality of the biomass.
Current demand for peat within the UK growing media industry amounts to 2.5 million m3. Moss farms are being established in Germany [3] and the Netherlands, following on from the research and development work carried out by Greifswald [4]
Benefits for Climate Change Control, Peat and Biodiversity
- Carbon emission reduction will start after rewetting the peat.
- Active Carbon storage starts when full moss cover is established.
- Peat is protected and will no longer be blown away and lost.
- The moss is a miniature nature reserve for wildlife, rarer wetland plants and insects. Rotational harvesting could maximise this benefit.
- Land that tends to be wet or shallow peat areas could be suitable for sphagnum farming and help grow the nature recovery network area.
Crop Notes Sphagnum moss is fascinating, holding 20x its weight in water, thriving on wet waterlogged soil. The plant is a long lived perennial and in the wild receives most of its water from rainfall and prefers low nutrient levels. As a farm crop it can tolerate slightly enriched water but may need weed management.
Establishing a moss farm takes about a year, starting with a level, bare peat surface during the late spring-early summer and the irrigation system ready before planting. The propagules are spread over the surface and require humidity to establish. Straw mulching or other protective covers will help.
For greatest yield keep the Sphagnum wet, but not flooded. This can be achieved by raising the ground water, to 5cm below the ground surface5 or surface irrigation applied directly onto the moss. Using irrigation from above rather than raising the water table may also be preferable as the moss could be cultivated without risk to surrounding land where neighbouring farms have concerns over the impact of a paludiculture farm on their conventional crops.
Once established, a dense carpet of moss forms, increasing in thickness annually. Harvesting is when the thickness is optimum for a high value, quality crop. Expected yield potential; 3.7 – 6.9 t dry matter (DM) ha-1 yr-1 [5] The cutting depth influences the moss regeneration ability and time.
The optimum harvesting period appears to be every third year, timing depends on site and moss thickness. This suggests a potential system to be a series of moss beds, with a rotational cropping programme.
Indicative costs are based on trials. Site preparation, irrigation options and plant material choice will influence the cost but on a full scale farm operation and as the system matures, costs will reduce.
Market Demand: Alternative peat replacement in growing media. The market potential for sphagnum moss is strong because of its good water holding capacity and ability to act as a blank canvas for nutrients. Demand from Europe for growing media is expected to grow and the use of peat as a component is globally being reduced.
Biomedical: Sphagnum was used in WW1 and WW2 as a ‘first field dressing’ because of the good absorbency and antimicrobial properties. Then as a natural absorbent material for sanitary pads and nappies. Johnson and Johnson took out several patents. It has also been found that sphagnum moss has potential use as food packaging and preventing food spoiling. Research and testing is ongoing.
Architectural applications in Green Walls for its cleansing properties. https://g-pulse.com/moss-wall
Key Points
- Sphagnum can be established, grown and harvested as a crop
- Water management and quality of water are important factors
- Growing the crop provides climate change and environmental benefits
- Research is ongoing to fully calculate the economic benefit [6]
- Government subsidy, possibly through ELMS [7], or payment for ecosystem services is needed in the crop establishment period.
- Potential markets will require sufficient, continuous supplies of moss.
References:
1 W.Wichtmann, et al (2016) Paludiculture – productive use of wet peatlands: Climate protection – biodiversity – regional economic benefits. Schweitzerbart, Stuttgart. pp. 100- 101. (ISBN: 9783510652839)
5 Gaudig, G., et al 2017. Sphagnum farming from species selection to the production of growing media: a review. 20(13), 130. http://www.miresandpeat.net/pages/volumes/map20map2013.php; 10.19189/MaP.2018.OMB.340
6 S. Wichmann, M. Krebs, S. Kumar, G. Gaudig Paludiculture on former bog grassland: Profitability of Sphagnum farming in North West Germany, Mires and Peat, Volume 26 (2020), Article 08, 18 pp
Acknowledgements: Photos, Micropropagation Services (E.M.) Ltd, under the trading name BeadaMoss®, own rights in inventions relating to Sphagnum Farming. This technology is currently patent pending under application numbers GB1907229.7 and GB1907228.9.