Restoration of cut-over bogs by floating raft formation: An experimental feasibility study

Abstract

Stimulation of floating peat by the introduction of poorly humified peat from four cut-over bogs in The Netherlands was studied in a one-year outdoor experiment. The pH of the various peat substrates was increased by adding different amounts of lime: 0-2 to 4-8 g-CaCO3.kg(-1) fresh peat. Both peat type and lime addition were found to affect the buoyancy of the peat substrates. Low nutrient concentrations in the peat, together with a high bulk density, proved to be unfavourable for creating floating peat. Three of the peat types proved to be too acidic (pH < 4.5) to produce sufficient methane (ca. 400-600 mumol.L-1), and buoyancy was only achieved if lime was mixed in with the peat. The smallest amount of lime added (2 g.kg(-1) fresh peat) was sufficient to maintain buoyancy for at least one year. Lime addition did not stimulate nutrient mobilization by mineralization, although P, N and K concentrations in the peat water were relatively high. It is concluded that floating peat can be initiated by the introduction of poorly humified peat. If the peat substrates are too acidic, lime can be added to stimulate buoyancy of the peat. Results are discussed in relation to restoration prospects.