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

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 (11·16 µmol CO₂ m⁻²s⁻¹), whereas the flux was reduced by 38 and 59 per cent in mowed site and at 15‐cm depth, respectively. The flux from afforested area was found 5·70 µmol CO₂ m⁻²s⁻¹, which is 50 per cent 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 (0·89–1·12 µmol CO₂ m⁻²s⁻¹) and highest during late monsoon (3–3·5 µmol CO₂ m⁻²s⁻¹). During late monsoon, the moisture content was found to be higher (6–7·5 per cent), which leads to higher microbial activity and decomposition. In the same area under grass cover, soil CO₂ flux was found to be higher (8·94 µmol 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. Copyright © 2012 John Wiley & Sons, Ltd.