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A Process‐Based Model for Predicting Soil Carbon Dioxide Efflux and Concentration
Author(s) -
Pumpanen Jukka,
Ilvesniemi Hannu,
Hari Pertti
Publication year - 2003
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2003.4020
Subject(s) - soil respiration , soil science , water content , humus , environmental science , soil carbon , carbon dioxide , respiration , soil horizon , environmental chemistry , chemistry , soil water , geology , botany , geotechnical engineering , organic chemistry , biology
Decomposition and root respiration processes, important to C cycling in terrestrial ecosystems, are affected by soil temperature, soil moisture, and other soil properties. For studying the effect of these factors on soil CO 2 efflux and soil‐air CO 2 concentration, a dynamic model was developed. In the model, soil was described in successive layers and the processes and soil properties were described separately for each layer. The CO 2 in soil layers originated from root and microbial respiration, which were assumed to depend on soil temperature and moisture multiplicatively. The CO 2 flux between the layers was driven by diffusion, which depended on CO 2 concentration, porosity, and temperature of the layers. The model predictions of CO 2 effluxes and soil CO 2 concentrations were close to those observed in the field. There was a clear seasonal pattern in the soil CO 2 efflux and the soil‐air CO 2 concentration. According to the model analysis, most of the CO 2 was produced in the humus layer throughout the year, but the contribution of deeper layers to total respiration was higher in winter than in summer. The CO 2 concentration was strongly dependent on factors affecting the diffusion properties of the soil, that is, the soil porosity and the soil‐water content. The CO 2 efflux and the soil‐air CO 2 concentration were overestimated, if the soil‐water content was not included in the soil respiration model. The model developed in this study provided a simple and an effective tool for studying the factors affecting soil CO 2 efflux and CO 2 concentration.