SOIL CO2 FLUX IN GRASSLAND, AFFORESTED LAND AND RECLAIMED COALMINE OVERBURDEN DUMPS: A CASE STUDY

摘要

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 (R) infrared gas analyzer, LICOR Inc., Lincoln, NE). The highest soil CO2 flux was observed in natural grassland (11 center dot 16 mu molCO2 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 center dot 70 mu molCO2 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 center dot 89-1 center dot 12 mu mol CO2 m-2s-1) and highest during late monsoon (3-3 center dot 5 mu mol CO2 m-2s-1). During late monsoon, the moisture content was found to be higher (6-7 center dot 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 center dot 94 mu mol 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