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.

Understanding the relationship between soil properties and litter chemistry in three forest communities in tropical forest ecosystem

In this study, we investigated the relationship between soil properties and litter chemistry in three forest communities, i.e., Sal mixed forest (SMF), dry mixed forest (DMF), and teak plantation forest (TPF), in tropical deciduous forest ecosystem in North India. Fresh leaf litter and soil samples were collected at two soil depths (0-15 and 15-30 cm) from all these three forest communities. Litter bag experiment was also conducted to know differences in litter nutrients after its decomposition. The concentrations (mg kg^-1) of different nutrients such as sodium (Na) 2.6, potassium (K) 38.5, calcium (Ca) 425, and carbon (C) 45.54% were highest in fresh litter collected from DMF. Total organic carbon (g kg^-1) was significantly higher in SMF (19.23) in comparison to DMF (18.41) and TPF (13.61) at 0-15-cm soil depth. Na, K, Ca, available P, total P, available N, and total N were highest in DMF soil. We observed significantly positive correlation between all nutrients of litter and soil. Although soil bulk density (BD) and particle density (PD) showed their significant negative correlation with litter C, total porosity was positively correlated. Similarly, litter Na has its significant negative correlation with BD and positive correlation with PD. The litter chemistry played a significant role in changing soil pH and TOC. All litter nutrients, except total P, have their significant positive correlation with soil pH. Total P, C, and N of litter have their significant positive correlation with total soil organic carbon. This indicates that litter chemistry and soil properties have specific relation among them despite unique species composition in each forest community.

Isolated Ficus trees deliver dual conservation and development benefits in a rural landscape

Many of the world's rural populations are dependent on the local provision of economically and medicinally important plant resources. However, increasing land-use intensity is depleting these resources, reducing human welfare, and thereby constraining development. Here we investigate a low cost strategy to manage the availability of valuable plant resources, facilitated by the use of isolated Ficus trees as restoration nuclei. We surveyed the plants growing under 207 isolated trees in Assam, India, and categorized them according to their local human-uses. We found that Ficus trees were associated with double the density of important high-grade timber, firewood, human food, livestock fodder, and medicinal plants compared to non-Ficus trees. Management practices were also important in determining the density of valuable plants, with grazing pressure and land-use intensity significantly affecting densities in most categories. Community management practices that conserve isolated Ficus trees, and restrict livestock grazing and high-intensity land-use in their vicinity, can promote plant growth and the provision of important local resources.