Sphagnum farming initiatives in Canada: an overview

TitleSphagnum farming initiatives in Canada: an overview
Publication TypeConference Proceedings
Year of Conference2018
AuthorsNanchen, M.G., S. Hugron, C. Brown, M. Strack, J.S. Price, and L. Rochefort
Conference Name20th EGU General Assembly
Date Published04/2018
Conference LocationVienna, Austria
Abstract

Sphagnum farming is the cultivation of non-decomposed Sphagnum fibres on a cyclic and renewable basis on wet organic soil, and therefore is a form of paludiculture. There is an increasing demand for Sphagnum fibres in the horticultural and plant packaging market. By replacing peat from natural deposit or Sphagnum fibers harvested in natural peatlands, cultivated Sphagnum fibers from Sphagnum farms could reduce environmental impacts of peat extraction while maintaining the quality of growing substrates. Research on Sphagnum farming has made significant advances in the last decade but optimizing the factors to increase Sphagnum biomass accumulation need further investigations. Since 2013, two Sphagnum farms with automated irrigation were implemented in Eastern Canada to produce Sphagnum fibres. In both sites, two targets for water table (-10 cm and -20 cm), different spatial positioning of canals as well as subsurface irrigation drains were tested. The productivity of the different Sphagnum species introduced, the hydrology of the sites and the carbon exchanges in relation to the water level as well as the design of the farming basins have been monitored. After three and four growing seasons, the following conclusions were drawn : 1) Sphagnum productivity in irrigated basins is higher than in unmanaged basins: a water table maintained around -10 cm tripled the biomass accumulation whereas when maintained around -20 cm the biomass accumulation doubled in comparison to unmanaged Sphagnum culture basins, 2) maintaining a stable water table (range below 15 cm) resulted in higher CO2 uptakes by the moss layer, 3) hydrology of drainage basins can be affected by ground water inputs outside the experimental area (i.e. from adjacent unrestored trenches), and by the position of the drainage canals in the landscape. Results from other small-scale trials for optimizing yields and harvesting of biomass will also be presented. Overall, our experiments have shown that the amplitude reduction of water table fluctuation and water distribution by automated irrigation is critical.