Modeling the impacts of temperature and precipitation changes on soil CO2 fluxes from a Switchgrass stand recently converted from cropland.

Abstract Switchgrass ( Panicum virgatum L.) is a perennial C 4 grass native to North America and successfully adapted to diverse environmental conditions. It offers the potential to reduce soil surface carbon dioxide (CO 2 ) fluxes and mitigate climate change. However, information on how these CO 2 fluxes respond to changing climate is still lacking. In this study, CO 2 fluxes were monitored continuously from 2011 through 2014 using high frequency measurements from Switchgrass land seeded in 2008 on an experimental site that has been previously used for soybean ( Glycine max L.) in South Dakota, USA. DAYCENT, a process-based model, was used to simulate CO 2 fluxes. An improved methodology CPTE [Combining Parameter estimation (PEST) with “Trial and Error” method] was used to calibrate DAYCENT. The calibrated DAYCENT model was used for simulating future CO 2 emissions based on different climate change scenarios. This study showed that: (i) the measured soil CO 2 fluxes from Switchgrass land were higher for 2012 which was a drought year, and these fluxes when simulated using DAYCENT for long-term (2015–2070) provided a pattern of polynomial curve; (ii) the simulated CO 2 fluxes provided different patterns with temperature and precipitation changes in a long-term, (iii) the future CO 2 fluxes from Switchgrass land under different changing climate scenarios were not significantly different, therefore, it can be concluded that Switchgrass grown for longer durations could reduce changes in CO 2 fluxes from soil as a result of temperature and precipitation changes to some extent.