Extracting peat oxidation from ecosystem respiration with the PEATLAND-VU model

Measuring carbon dioxide (CO₂) exchange between ecosystem and atmosphere is a widely used method to determine peat oxidation from drained peat soils. The net ecosystem carbon balance (NECB), which is the net CO₂ flux over a year with accounting for harvest (C-export), is taken as an estimate for peat oxidation. This might be the case if the short-term carbon cycle, dominated by vegetation, is in balance within one year. Carbon processes are, however, often complex determined by weather conditions and interactions between different carbon pools. To better estimate the contribution of the soil carbon pools, including peat oxidation, to the measured CO₂ fluxes within a season or a year, a reliable model is needed. 

PEATLAND-VU is a 1D process based model, consisting of four submodels for 1) soil physics (water table, soil temperature and soil moisture), 2) biomass production, 3) CH₄ production, oxidation and transport, and 4) CO₂ production. CO₂ production is the sum of decomposition from different soil organic matter (SOM) pools, like litter, root exudates, microbial biomass and peat. We improved the PEATLAND-VU model and calibrated it for two intensively used drained peat meadows in the Netherlands, that are equipped with sensors for measuring continuously CO₂ fluxes and all environmental variables related to that. These sites have a reference field and a field with elevated groundwater level.

In this presentation, we discuss the model performance on these sites. We will show the contribution of the different sources to the ecosystem respiration, and how the modelled peat oxidation relates to the measured NECB.