Water quality impacts of bare peat revegetation with lime and fertiliser application

• Published in: Applied geochemistry Vol. 85; pp. 97 - 105
• Main Authors: Stimson, A.G., Allott, T.E.H., Boult, S., Evans, M.G., Pilkington, M., Holland, N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2017
• Subjects: DOC; Peatlands; Restoration; Restoration; DOC; Peatlands
• ISSN: 0883-2927; 1872-9134
• DOI: 10.1016/j.apgeochem.2017.09.003

Loss of peatland vegetation is a global problem with negative consequences for the quality of catchment drainage waters. Vegetation can be lost through a combination of human and natural processes, leading to areas of exposed bare peat frequently accompanied by loss of surface moisture due to drainage or gullying. Waters draining such degraded peatlands are likely to have increased levels of dissolved organic carbon (DOC) and other nutrients, which can adversely impact the global climate, drinking water supplies and freshwater ecology. Consequently peatland revegetation efforts have become widespread. This paper presents results from a four-year study conducted to monitor the water quality impacts of a bare peat revegetation approach, which used landscape scale application of lime and fertiliser to encourage a grass nurse crop. This study considers an area of severely degraded blanket peat in the UK uplands, with large areas of bare peat prior to revegetation and provides the largest field dataset to date on the effects of this method on catchment run-off waters. Despite concerns that liming could increase DOC concentrations, the revegetation method is not shown to have this effect over the time period, and interestingly results in short term periods of suppression. The mechanism for this novel and unexpected finding merits further investigation and results in reduced DOC concentration, by up to 14 mg/l or 50% of control values, combined with periods of reduced colour carbon ratios. The data show that other nutrients were largely unaffected although rates of phosphate (PO43−) export were above recommended levels in the first year of application, suggesting initial phosphorus (P) application rates may require adjustment. Further investigation is required to consider the longer term effects of this restoration method as the vegetation matures. •4-year dataset covers peatland revegetation with lime and fertiliser application.•Impacts on run-off waters to headwater fluvial systems monitored.•No lasting impact on Dissolved Organic Carbon, but temporary suppression evident.•Maximum Dissolved Organic Carbon suppression recorded is 50% of control values.•Initial high phosphate export suggests application regime may need adjustment.