Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

  • Reimo Kindler
  • Jan Siemens
  • Martin Kaupenjohann
  • Bruce A. Osborne
  • Christian H. Bernhofer
  • Thomas Grünwald
  • Bernhard Vowinckel
  • Nina Buchmann
  • Werner Eugster
  • Matthias J. Zeeman
  • Pierre Cellier
  • Simon Lehuger
  • Benjamin Loubet
  • Gerd Gleixner
  • Marion Schrumpf
  • Janine Seyfferth
  • Cindy Tefs
  • Alexander Heim
  • Michael W.I. Schmidt
  • Andreas Ibrom
  • Klaus Steenberg Larsen
  • Kim Pilegaard
  • Stephanie K. Jones
  • Ute M. Skiba
  • Mark A. Sutton
  • Michael B. Jones
  • Katja Klumpp
  • Jean Francois Soussana
  • Werner Leo Kutsch
  • Rebecca M. Mckenzie
  • Eddy J. Moors
  • Corinna Rebmann
  • Matthew Saunders
  • Klaus Kaiser

Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH 4), at forests, grasslands, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its δ 13C signature. Leaching of biogenic DIC was 8.3±4.9gm -2yr -1 for forests, 24.1±7.2gm -2yr -1 for grasslands, and 14.6±4.8gm -2yr -1 for croplands. DOC leaching equalled 3.5±1.3gm -2yr -1 for forests, 5.3±2.0gm -2yr -1 for grasslands, and 4.1±1.3gm -2yr -1 for croplands. The average flux of total biogenic carbon across land use systems was 19.4±4.0gCm -2yr -1. Production of DOC in topsoils was positively related to their C/N ratio and DOC retention in subsoils was inversely related to the ratio of organic carbon to iron plus aluminium (hydr)oxides. Partial pressures of CO 2 in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO 2. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5-98% (median: 22%) of net ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24-105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small solubility of CO 2 in acidic forest soil solutions and large NEE. Leaching of CH 4 proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems.

Original languageEnglish
JournalGlobal Change Biology
Volume17
Issue number2
Pages (from-to)1167-1185
Number of pages19
ISSN1354-1013
DOIs
Publication statusPublished - 01.02.2011
Externally publishedYes