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Carbon exchange of grazed pasture on a drained peat soil
Author(s) -
Nieveen Joost P.,
Campbell David I.,
Schipper Louis A.,
Blair Ian J.
Publication year - 2005
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2005.00929.x
Subject(s) - peat , environmental science , water content , ecosystem respiration , pasture , eddy covariance , hydrology (agriculture) , histosol , water table , soil respiration , soil water , ecosystem , soil carbon , soil science , agronomy , soil organic matter , ecology , geology , soil biodiversity , groundwater , geotechnical engineering , biology
Land‐use changes have contributed to increased atmospheric CO 2 concentrations. Conversion from natural peatlands to agricultural land has led to widespread subsidence of the peat surface caused by soil compaction and mineralization. To study the net ecosystem exchange of carbon (C) and the contribution of respiration to peat subsidence, eddy covariance measurements were made over pasture on a well‐developed, drained peat soil from 22 May 2002 to 21 May 2003. The depth to the water table fluctuated between 0.02 m in winter 2002 to 0.75 m during late summer and early autumn 2003. Peat soil moisture content varied between 0.6 and 0.7 m 3 m −3 until the water table dropped below 0.5 m, when moisture content reached 0.38 m 3 m −3 . Neither depth to water table nor soil moisture was found to have an effect on the rate of night‐time respiration (ranging from 0.4–8.0 μmol CO 2 m −2 s −1 in winter and summer, respectively). Most of the variance in night‐time respiration was explained by changes in the 0.1 m soil temperature ( r 2 =0.93). The highest values for daytime net ecosystem exchange were measured in September 2002, with a maximum of −17.2 μmol CO 2 m −2 s −1 . Grazing events and soil moisture deficiencies during a short period in summer reduced net CO 2 exchange. To establish an annual C balance for this ecosystem, non‐linear regression was used to model missing data. Annually integrated (CO 2 ) C exchange for this peat–pasture ecosystem was 45±500 kg C ha −1 yr −1 . After including other C exchanges (methane emissions from cows and production of milk), the net annual C loss was 1061±500 kg C ha −1 yr −1 .