Reproducing CO2 exchange rates of a crop rotation at contrasting terrain positions using two different modelling approaches

摘要: In undulating landscapes erosion is largely responsible for the spatial distribution of C stocks in agricultural soils. Whether these contribute to global atmospheric CO2 concentrations as source or sink under constant debate. Periodic measurements were carried out at a hummocky ground moraine site grown with maize, fodder rye and sorghum using dynamic non-steady-state transparent opaque chambers. Flux calculation was conducted empirical gap-filling model Hoffmann et al. (2015b), which uses temperature radiation simulate ecosystem respiration (Reco) gross primary production (GPP) calculate net exchange (NEE). This compared process-based agro-ecosystem simulation model, MONICA, tested its ability Reco, GPP NEE, benchmark. Both models simulated Reco same order magnitude, MONICA simulating considerably higher amount produced by photosynthesis maize less deviating other crops consumed all model. agree flux patterns, but show considerable differences directly after harvest during bare soil periods. Strengths weaknesses both approaches discussed synergies applying conjunction identified way that (i) may act an independent method identify significant deviations from optimum crop growth pattern thus point times assumptions NEE be violated (ii) calibration benchmark simulations.