Wetter, but not wet enough: Limited greenhouse gas mitigation effects of subsurface irrigation and blocked ditches in an intensively cultivated grassland on fen peat

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Autorschaft

  • Sebastian Heller
  • Bärbel Tiemeyer
  • Willi Oehmke
  • Peter Gatersleben
  • Ullrich Dettmann

Organisationseinheiten

Externe Organisationen

  • Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
  • Landwirtschaftskammer Niedersachsen
Forschungs-netzwerk anzeigen

Details

OriginalspracheEnglisch
Aufsatznummer110367
Seitenumfang17
FachzeitschriftAgricultural and Forest Meteorology
Jahrgang362
Frühes Online-Datum26 Dez. 2024
PublikationsstatusElektronisch veröffentlicht (E-Pub) - 26 Dez. 2024

Abstract

High-intensity grassland farming on peatlands is a profitable land use option in Western and Central Europe. This highly productive land use requires extensive drainage measures and regular grassland renewal. The drainage practice in particular substantially increases peat mineralisation, resulting in high emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and nitrous oxide (N2O). Against this, a controlled raising of the water level (WL) by subsurface irrigation (SI) or ditch blocking (DB) has been proposed as a compromise between reducing the GHG emissions and maintaining grassland use on peatlands. We tested this assumption by measuring the full set of GHGs over four years for three water management systems (SI, DB, ditch drainage as control) in combination with three grassland renewal treatments (direct sowing, shallow ploughing, original sward as control) on an intensively used fen grassland in Northwest Germany. The mean annual WL was successfully raised by SI to −0.25 m below the soil surface, while the DB unit remained at a similar level (−0.37 m) as the control (−0.38 m). However, CO2 emissions were only marginally reduced by SI due to high variability between sites and years. Partially higher CO2 emissions may have been caused by a higher temperature sensitivity of the heterotrophic respiration at intermediate WLs. Partially lower CO2 emissions may reflect increased carbon uptake by root growth (Juncus effuses) rather than reduced peat mineralisation. The GHG mitigation potential of the SI system remained negligible in this study, as the small CO2 reduction was offset by increased CH4 and N2O emissions. The average emissions of the DB system were similar to those of the control unit. Both renewal treatments increased N2O emissions for approximately two years. Overall, our study results do not support the use of SI as a GHG mitigation measure for intensively used fen grasslands.

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Wetter, but not wet enough: Limited greenhouse gas mitigation effects of subsurface irrigation and blocked ditches in an intensively cultivated grassland on fen peat. / Heller, Sebastian; Tiemeyer, Bärbel; Oehmke, Willi et al.
in: Agricultural and Forest Meteorology, Jahrgang 362, 110367, 01.03.2025.

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Heller S, Tiemeyer B, Oehmke W, Gatersleben P, Dettmann U. Wetter, but not wet enough: Limited greenhouse gas mitigation effects of subsurface irrigation and blocked ditches in an intensively cultivated grassland on fen peat. Agricultural and Forest Meteorology. 2025 Mär 1;362:110367. Epub 2024 Dez 26. doi: 10.1016/j.agrformet.2024.110367
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title = "Wetter, but not wet enough: Limited greenhouse gas mitigation effects of subsurface irrigation and blocked ditches in an intensively cultivated grassland on fen peat",
abstract = "High-intensity grassland farming on peatlands is a profitable land use option in Western and Central Europe. This highly productive land use requires extensive drainage measures and regular grassland renewal. The drainage practice in particular substantially increases peat mineralisation, resulting in high emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and nitrous oxide (N2O). Against this, a controlled raising of the water level (WL) by subsurface irrigation (SI) or ditch blocking (DB) has been proposed as a compromise between reducing the GHG emissions and maintaining grassland use on peatlands. We tested this assumption by measuring the full set of GHGs over four years for three water management systems (SI, DB, ditch drainage as control) in combination with three grassland renewal treatments (direct sowing, shallow ploughing, original sward as control) on an intensively used fen grassland in Northwest Germany. The mean annual WL was successfully raised by SI to −0.25 m below the soil surface, while the DB unit remained at a similar level (−0.37 m) as the control (−0.38 m). However, CO2 emissions were only marginally reduced by SI due to high variability between sites and years. Partially higher CO2 emissions may have been caused by a higher temperature sensitivity of the heterotrophic respiration at intermediate WLs. Partially lower CO2 emissions may reflect increased carbon uptake by root growth (Juncus effuses) rather than reduced peat mineralisation. The GHG mitigation potential of the SI system remained negligible in this study, as the small CO2 reduction was offset by increased CH4 and N2O emissions. The average emissions of the DB system were similar to those of the control unit. Both renewal treatments increased N2O emissions for approximately two years. Overall, our study results do not support the use of SI as a GHG mitigation measure for intensively used fen grasslands.",
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TY - JOUR

T1 - Wetter, but not wet enough

T2 - Limited greenhouse gas mitigation effects of subsurface irrigation and blocked ditches in an intensively cultivated grassland on fen peat

AU - Heller, Sebastian

AU - Tiemeyer, Bärbel

AU - Oehmke, Willi

AU - Gatersleben, Peter

AU - Dettmann, Ullrich

N1 - Publisher Copyright: © 2024

PY - 2024/12/26

Y1 - 2024/12/26

N2 - High-intensity grassland farming on peatlands is a profitable land use option in Western and Central Europe. This highly productive land use requires extensive drainage measures and regular grassland renewal. The drainage practice in particular substantially increases peat mineralisation, resulting in high emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and nitrous oxide (N2O). Against this, a controlled raising of the water level (WL) by subsurface irrigation (SI) or ditch blocking (DB) has been proposed as a compromise between reducing the GHG emissions and maintaining grassland use on peatlands. We tested this assumption by measuring the full set of GHGs over four years for three water management systems (SI, DB, ditch drainage as control) in combination with three grassland renewal treatments (direct sowing, shallow ploughing, original sward as control) on an intensively used fen grassland in Northwest Germany. The mean annual WL was successfully raised by SI to −0.25 m below the soil surface, while the DB unit remained at a similar level (−0.37 m) as the control (−0.38 m). However, CO2 emissions were only marginally reduced by SI due to high variability between sites and years. Partially higher CO2 emissions may have been caused by a higher temperature sensitivity of the heterotrophic respiration at intermediate WLs. Partially lower CO2 emissions may reflect increased carbon uptake by root growth (Juncus effuses) rather than reduced peat mineralisation. The GHG mitigation potential of the SI system remained negligible in this study, as the small CO2 reduction was offset by increased CH4 and N2O emissions. The average emissions of the DB system were similar to those of the control unit. Both renewal treatments increased N2O emissions for approximately two years. Overall, our study results do not support the use of SI as a GHG mitigation measure for intensively used fen grasslands.

AB - High-intensity grassland farming on peatlands is a profitable land use option in Western and Central Europe. This highly productive land use requires extensive drainage measures and regular grassland renewal. The drainage practice in particular substantially increases peat mineralisation, resulting in high emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and nitrous oxide (N2O). Against this, a controlled raising of the water level (WL) by subsurface irrigation (SI) or ditch blocking (DB) has been proposed as a compromise between reducing the GHG emissions and maintaining grassland use on peatlands. We tested this assumption by measuring the full set of GHGs over four years for three water management systems (SI, DB, ditch drainage as control) in combination with three grassland renewal treatments (direct sowing, shallow ploughing, original sward as control) on an intensively used fen grassland in Northwest Germany. The mean annual WL was successfully raised by SI to −0.25 m below the soil surface, while the DB unit remained at a similar level (−0.37 m) as the control (−0.38 m). However, CO2 emissions were only marginally reduced by SI due to high variability between sites and years. Partially higher CO2 emissions may have been caused by a higher temperature sensitivity of the heterotrophic respiration at intermediate WLs. Partially lower CO2 emissions may reflect increased carbon uptake by root growth (Juncus effuses) rather than reduced peat mineralisation. The GHG mitigation potential of the SI system remained negligible in this study, as the small CO2 reduction was offset by increased CH4 and N2O emissions. The average emissions of the DB system were similar to those of the control unit. Both renewal treatments increased N2O emissions for approximately two years. Overall, our study results do not support the use of SI as a GHG mitigation measure for intensively used fen grasslands.

KW - Carbon dioxide

KW - Grassland renovation

KW - Histosol

KW - Nitrous oxide

KW - Peatland

KW - Water management

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U2 - 10.1016/j.agrformet.2024.110367

DO - 10.1016/j.agrformet.2024.110367

M3 - Article

AN - SCOPUS:85213263075

VL - 362

JO - Agricultural and Forest Meteorology

JF - Agricultural and Forest Meteorology

SN - 0168-1923

M1 - 110367

ER -