A model for soil CO2 production and transport 2:: Application to a Florida Pinus elliotte plantation

In this paper, the one-dimensional, process-based soil CO2 model (PATCIS) described in Part 1 is parameterized and validated with field data collected in a mature slash pine plantation in Florida. The results of a model sensitivity analysis show that CO2 efflux in the plantation is most sensitive to soil temperature and associated parameters and that moisture content in the mineral soil seriously hinders gas transport in summer and may restrict soil respiration in winter. Annual CO2 released from the soil surface is estimated by the model to be ca. 14 t C ha(-1) year(-1). Of the total CO2 released from the soil surface, ca. 53% comes from live root respiration and 47% from decomposition of organic matter. Most CO2 is produced in the surface layer and the top 15 cm of mineral soil, with contributions of ca. 43% and 32% of the total annual efflux, respectively. Simulated CO2 concentrations in the soil gas varied with a range of 0.42% to 4.6% at a depth of 100 cm, and 0.04% to 0.06% at 2 cm through the year. Simulated CO2 efflux and the different components of soil respiration are in good agreement with field experiments and previous studies. (C) 1999 Elsevier Science B.V. All rights reserved.