Almost 40 years after raised bog restoration on black peat: How did nutrient levels in soil and water change?

Abstract

Restoration of the bog known as the Leegmoor was accompanied by multiple challenging factors such as lack of a white peat layer, strong water table fluctuations and inhibited lateral water movement. The project started in 1983 and was supported by scientific monitoring. Now, almost 40 years later, the monitoring has been repeated to gauge success. As part of this initiative we investigated nutrient dynamics by monitoring soil and water chemistry (NH4+, NO3-, PO43-, pH, Nt, Pt) and soil water content in 2019–2020 and comparing our results with data from the 1980s and 1990s. Soil water content had increased significantly. Soil NO3--N content had decreased significantly and was mostly below the detection limit, while pH and NH4+-N had not changed. Pore water PO43--P concentrations remained above those observed in near-natural bogs, while nutrients (except NH4+-N) in the surface water had decreased to levels observed in near-natural bogs. Most of the observed nutrients had decreased, some to near-natural levels, although the Leegmoor continued to receive an atmospheric supply of nutrients from adjacent agricultural areas. Our results indicate translocation of nutrients into the vegetation, which has developed substantially, but this process can be expected to end at some point.

Keywords

• leegmoor
• nutrient relocation
• peat extraction
• vegetation
• nutrient concentrations