Interaction of abiotic factor on soil CO2 efflux in three forest communities in tropical deciduous forest from India.

Environmental factors along with soil physico-chemical properties play a significant role on the diurnal trend of soil CO2 efflux. Soil CO2 efflux in Indian tropical forests is poorly studied. We studied the soil CO2 efflux in a representative tropical deciduous forest at Katerniaghat Wildlife Sanctuary (KWLS), Uttar Pradesh. The three forest communities namely dry mixed (DMF), Sal mixed (SMF), and Teak plantation (TPF) were selected for measuring soil CO2 efflux in the summer season during April to May 2017 using automated LI-COR 8100 soil CO2 flux system. Soil physico-chemical parameters were also studied in the three abovementioned forest communities. We also measured the different microclimatic variables at forest understorey in all three communities during the summer season. Total day time soil CO2 efflux of 826.70, 1089.24, and 828.94 (μmolCO2 m-2d-1) was observed in TPF, SMF, and DMF respectively. Soil CO2 efflux observed significant differences (P < 0.01) among the three forest communities studied for the summer season in tropical deciduous forest of Terai Himalaya. Average soil CO2 efflux rate (μmol CO2 m-2 s-1) of 4.06 ± 0.36, 5.03 ± 0.45, and 4.37 ± 0.79 was observed in TPF, SMF, and DMF, respectively, which is positively correlated with total organic carbon (TOC) and water holding capacity (WHC) among soil physico-chemical variables. Among microclimatic variables, soil temperature (ST, °C) and air temperature (AT, °C) observed strong positive correlation with day time soil CO2 efflux in all three communities. Significant increase in soil CO2 flux was observed with increasing air and soil temperature (AT and ST) in DMF and SMF. Maximum TOC of 19.23 g Kg-1 was observed in SMF among all communities in the summer season. The result showed that soil CO2 efflux is closely associated with TOC, WHC, AT, and ST for Indian deciduous forest ecosystems.