Soil co2 flux in grassland, afforested land and reclaimed coalmine overburden dumps: A case study

Abstract

The aim of this study was to measure the in situ soil CO2 flux from grassland, afforested land and reclaimed coalmine overburden dumps by using the automated soil CO2 flux system (LICOR-8100® infrared gas analyzer, LICOR Inc., Lincoln, NE). The highest soil CO2 flux was observed in natural grassland (11·16μmolCO2 m-2s-1), whereas the flux was reduced by 38 and 59percent in mowed site and at 15-cm depth, respectively. The flux from afforested area was found 5·70μmolCO2 m-2s-1, which is 50percent lower than natural grassland. In the reclaimed coalmine overburden dumps, the average flux under tree plantation was found to be lowest in winter and summer (0·89-1·12μmol CO2 m-2s-1) and highest during late monsoon (3-3·5μmol CO2 m-2s-1). During late monsoon, the moisture content was found to be higher (6-7·5percent), which leads to higher microbial activity and decomposition. In the same area under grass cover, soil CO2 flux was found to be higher (8·94μmol CO2 m-2s-1) compared with tree plantation areas because of higher root respiration and microbial activity. The rate of CO2 flux was found to be determined predominantly by soil moisture and soil temperature. Our study indicates that the forest ecosystem plays a crucial role in combating global warming than grassland however, to reduce CO2 flux from grassland, mowing is necessary. © 2012 John Wiley & Sons, Ltd.