All over the world, peatlands have been drained, often for agricultural purposes, resulting in CO₂ emissions, soil subsidence and biodiversity loss. To combat these negative effects, drained peatlands are being rewetted, but knowledge of the effects of rewetting on peat biogeochemistry is still incomplete, especially since a variety of rewetting methods and rewetting degrees exists. We conducted a mesocosm experiment in which we exposed 100 intact agricultural fen peat cores (80 cm, 20 cm Ø) to five different water levels (0, 20, 40, 60 cm and variable—surface), two nutrient application levels to mimic continued agricultural use, and two water origins. Over an eight-month period, we harvested above-ground plant biomass five times and sampled pore water at two depths each month. Samples were analysed for nutrients. Our results show increased phosphate and ammonium availability upon fully rewetting (0 cm—surface) and less so under partially rewetted circumstances (20 cm—surface). Above-ground biomass was strongly affected by nutrient application, especially in the high water level treatments. Vegetation was primarily N-limited, and N in the vegetation decreased with increasing water levels, indicating stronger nitrogen limitation upon rewetting. We conclude that nature restoration under fully rewetted conditions will likely be challenging as a result of the large release of nutrients from the system which may also affect surrounding nature areas. Furthermore, we conclude that partial rewetting combined with low-intensity agricultural use can be a solution to slow down the adverse effects of drainage, although this will lead to decreased agricultural production.

在世界各地，泥炭地经常出于农业目的而被排干，导致 CO ₂排放、土壤沉降和生物多样性丧失。为了对抗这些负面影响，正在对排水的泥炭地进行再润湿，但关于再润湿对泥炭生物地球化学影响的知识仍然不完整，特别是因为存在多种再润湿方法和再润湿程度。我们进行了一项中生态实验，将 100 个完整的农业沼泽泥炭核心（80 厘米、20 厘米直径）暴露于五个不同的水位（0、20、40、60 厘米和可变表面），模拟连续的两种养分施用水平农业用途和两个水源。在八个月的时间里，我们五次收获了地上植物生物量，并每月在两个深度采样孔隙水。对样品进行营养成分分析。我们的结果表明，完全再润湿（0 厘米 - 表面）时磷酸盐和铵的可用性增加，而在部分再润湿情况下（20 厘米 - 表面）则减少。地上生物量受到养分施用的强烈影响，特别是在高水位处理中。植被主要是氮限制的，并且植被中的氮随着水位的增加而减少，表明在再湿润时更强的氮限制。我们的结论是，由于系统中营养物质大量释放，这也可能影响周围的自然区域，因此在完全再润湿条件下的自然恢复可能会具有挑战性。此外，我们得出的结论是，部分再润湿与低强度农业使用相结合可以成为减缓排水不利影响的解决方案，尽管这会导致农业产量下降。