High sensitivity of peat moisture content to seasonal climate in a cutaway peatland cultivated with a perennial crop (Phalaris arundinaceae, L.): A modeling study

Abstract

In this study, a process-based model was developed for studying the climatic sensitivity of the soil moisture content (θ) in a cutaway peatland cultivated with a perennial crop (Phalaris arundinaceae, L., RCG). The model was parameterized based on the canopy development and the soil properties measured in Linnansuo peatland in Eastern Finland. The model was also calibrated and validated by continuous measurements of meteorology, soil temperature, soil moisture and energy fluxes (eddy covariance system) during a wet year (2009) and a dry year (2010). The results showed that the model captured well the seasonal trend of the latent heat flux during the two-year period. Moreover, the model explained the major seasonal variations of the moisture content in multiple peat layers in the soil profile. Sensitivity analysis of the model showed that the fluctuation of the water table (WT) had little impact on the seasonal dynamics of the peat moisture content in the Linnansuo site. These results indicated that anthropological disturbances, such as peat extraction, drainage and energy crop cultivation, critically weakened the θ–WT interaction in the Linnansuo peatland. Moreover, these changes indicated the high climatic sensitivity of the peat moisture content especially to the variations of the seasonal pattern of precipitation.