Assessing the impact of land use on peat degradation in bogs in the Enns Valley, Austria

Peatlands are important reservoirs of soil organic carbon and nitrogen. Conversion of peatlands for agriculture and forestry has led to the degradation of over 50% of European peatlands – resulting in increased greenhouse gas emissions and groundwater contamination because of nutrient leaching. However, few studies have investigated the effects of land use change on peatlands with a similar history of development, and even fewer have explored these impacts on deeper peat layers (down to 80 cm). Here, we use multiple physicochemical indicators to assess peat degradation at three peat bog sites with varying land uses, but which share a similar origin. Peat cores were collected in triplicate from: a near-pristine bog, an afforested bog, and an agricultural intensive meadow. Principal component analysis and hierarchical clustering showed that intensive meadow management, with regular fertilizer application and drainage, primarily affected the reworked surface layer (0–30) cm, with higher bulk density and greater humification, leading to potentially irreversible changes in physical properties and carbon export dynamics. Meanwhile, deeper layers (30–80 cm) remained similar to near-pristine conditions. In contrast, peat afforestation management, typically involving deep ploughing and continued drainage over ca. 60 years, led to elevated inorganic nitrogen concentrations in the upper 0–40 cm, and increased bulk density and greater humification, down to 80 cm depth. Taken together, our results indicate that afforestation and intensive agricultural management practices—such as nutrient input, drainage, and deep ploughing—not only alter carbon and nutrient export dynamics and chemical characteristics, but also induce changes in the physical properties of peat, with notable distinctions between surface and deeper layers. Therefore, management and restoration strategies should be carefully developed to address the unique impacts of each specific land-use type.