Leaching of nitrogen, phosphorus and other solutes from a controlled drainage cultivated peatland in Ruukki, Finland
Pham, Tung; Yli-Halla, Markku; Marttila, Hannu; Lötjönen, Timo; Liimatainen, Maarit; Kekkonen, Jarkko; Läpikivi, Miika; Klöve, Björn; Joki-Tokola, Erkki (2023-09-01)
Pham, Tung
Yli-Halla, Markku
Marttila, Hannu
Lötjönen, Timo
Liimatainen, Maarit
Kekkonen, Jarkko
Läpikivi, Miika
Klöve, Björn
Joki-Tokola, Erkki
Elsevier
01.09.2023
Pham, Tung, et al. “Leaching of Nitrogen, Phosphorus and Other Solutes from a Controlled Drainage Cultivated Peatland in Ruukki, Finland.” Science of The Total Environment, vol. 904, Dec. 2023, p. 166769. https://doi.org/10.1016/j.scitotenv.2023.166769.
https://creativecommons.org/licenses/by/4.0/
© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
https://creativecommons.org/licenses/by/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202312073530
https://urn.fi/URN:NBN:fi:oulu-202312073530
Tiivistelmä
Abstract
Cultivated peatlands are important for grass production in Northern Europe, but the potential impact of nutrients leaching to surface waters is a major concern. Due to a lack of data on nitrogen (N), phosphorus (P) and organic carbon leaching, a monitoring programme was established at Ruukki (Siikajoki, Finland), an agricultural, subsurface drained peat site with a peat thickness of 20–80 cm. Concentrations and loading of N, P, and total organic carbon (TOC) were monitored, along with other water quality parameters for the field discharge, in 2018–2021. We observed N leaching from subsurface discharge to be 25 kg N ha−1 year−1 (range 11–40 kg N ha−1 year−1, 74 % as nitrate NO3-N). The least N leaching was recorded from plots of thinner peat topsoil and those with grass cover, while the majority of N leaching originated from thicker peat plots (bare or under barley) in spring. Leaching of N strongly decreased during periods of thick grass cover. Significant N leaching also occurred during the mild winter of 2019–2020, characterized by alternating freeze and thaw periods. Annual P loading from subsurface drainage was 0.30 kg P ha−1 (0.20–0.43 kg P ha−1), low compared to that of average cultivated soils in Finland. It was estimated that 13 % of the total N leaching and 50 % of the total P leaching occurred in surface runoff. Leaching of TOC was significant at 87 kg ha−1 year−1 (31–137 kg ha−1 year−1). Leaching of dissolved P and TOC increased with peat thickness. Abundant loading of sulfur and acidity indicates the oxidation of sulfidic material in the subsoil. Leaching concentrations correlated with discharge quantity, suggesting that mobilization processes during the dry periods resulted in leaching during high discharge periods. The results show the importance of avoiding bare peat soil for NO3-N leaching reduction, even during wintertime in cultivated peatlands.
Cultivated peatlands are important for grass production in Northern Europe, but the potential impact of nutrients leaching to surface waters is a major concern. Due to a lack of data on nitrogen (N), phosphorus (P) and organic carbon leaching, a monitoring programme was established at Ruukki (Siikajoki, Finland), an agricultural, subsurface drained peat site with a peat thickness of 20–80 cm. Concentrations and loading of N, P, and total organic carbon (TOC) were monitored, along with other water quality parameters for the field discharge, in 2018–2021. We observed N leaching from subsurface discharge to be 25 kg N ha−1 year−1 (range 11–40 kg N ha−1 year−1, 74 % as nitrate NO3-N). The least N leaching was recorded from plots of thinner peat topsoil and those with grass cover, while the majority of N leaching originated from thicker peat plots (bare or under barley) in spring. Leaching of N strongly decreased during periods of thick grass cover. Significant N leaching also occurred during the mild winter of 2019–2020, characterized by alternating freeze and thaw periods. Annual P loading from subsurface drainage was 0.30 kg P ha−1 (0.20–0.43 kg P ha−1), low compared to that of average cultivated soils in Finland. It was estimated that 13 % of the total N leaching and 50 % of the total P leaching occurred in surface runoff. Leaching of TOC was significant at 87 kg ha−1 year−1 (31–137 kg ha−1 year−1). Leaching of dissolved P and TOC increased with peat thickness. Abundant loading of sulfur and acidity indicates the oxidation of sulfidic material in the subsoil. Leaching concentrations correlated with discharge quantity, suggesting that mobilization processes during the dry periods resulted in leaching during high discharge periods. The results show the importance of avoiding bare peat soil for NO3-N leaching reduction, even during wintertime in cultivated peatlands.
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