CR 14:57-63 (2000)  -  doi:10.3354/cr014057

Effect of drainage on CO2 exchange patterns in an intensively managed peat pasture

B. O. M. Dirks1,*, A. Hensen2, J. Goudriaan1

1Wageningen Agricultural University, Dept of Theoretical Production Ecology, PO Box 430, 6700 AK Wageningen, The Netherlands
2Netherlands Energy Research Foundation, PO Box 1, 1755 ZG Petten, The Netherlands

ABSTRACT: Eddy correlation measurements of CO2 exchange were made in intensively managed peat pastures at 2 different groundwater tables during most of a growing season. F was separated into a respiratory and an assimilatory CO2 flux. The fit of the Arrhenius temperature response to Fr showed that Fr was generally higher at low groundwater tables. The fit of a hyperbolic irradiance response to Fa showed that Fa was also generally higher at low groundwater tables, more than compensating for higher Fr. The daily CO2 balance suggested that the low groundwater pasture was a larger CO2 sink or a smaller CO2 source than the high groundwater pasture during the measurement period. The difference in Fr between the groundwater tables was substantially less than the factor 2 difference in level of soil subsidence. This suggests that oxidization of soil organic matter was a relatively minor factor in soil subsidence.

KEY WORDS: Eddy correlation · CO2 exchange · Assimilatory flux · Respiratory flux · Pasture · Grassland · Peat · Drainage

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