The role of microorganisms in the decomposition of plant material is of immense importance. A large amount of plant litter is added annually to the soil through leaf fall and death of plants. As the plant materials fall on the ground, they are immediately attacked by various groups of soil microorganisms and soon after, the process of decomposition is initiated. Microorganisms being heterotrophic in their mode of nutrition are responsible for the decay processes and thereby releasing locked up nutrients from the dead bodies of plants and animals. The result of decomposition is that the building blocks required for life can be recycled. Decomposition is a determining factor for the functioning of ecosystems because litter dynamics (litter…show more content… Litter decomposition is the most important ecosystem process that releases carbon (C) back into the atmosphere, and provides nutrients in forms that can be used for plant and microbial growth (Duffy, 2002). Leaf litter production and its decomposition are the main processes regulating carbon and nitrogen cycles in natural ecosystems and some agro-ecosystems. Decomposition of leaf litter, by which organic matter and nutrients are returned to the forest soils, is a primary mechanism and has received considerable attention for sustainable soil fertility (Moretto et al., 2001; Xuluc-Tolosa et al., 2003). It forms an important nutrient pool and plays a significant role in regulating structure and function of forest ecosystem in a variety of ways. The ground litter production is the dominant pathway joining the living biological component to the non-living soil of the ecosystem through organic matter decomposition (Meentemeyer et al., 1982). In most ecosystems, more than 90% of the available nitrogen and phosphorus and more than 60% of mineral elements come from plant litter cycling (Chapin et al., 2002). Foliar tissues generally decompose on the soil surface where they are directly exposed to rainfall (Silver et al., 2010). In most terrestrial ecosystems, the amount of organic matter in the soil remains at a relatively constant level from one year to another.…show more content… The study sites selected were Upper Shillong at a higher altitude and Mawkyrdep at a lower altitude. The forest stand at a higher altitude is situated at 1861 m above sea level and the other forest stand at a lower altitude is situated at 889 m above sea level. The two common tree species found in the two selected forest stands of Meghalaya were Polyalthia longifolia and Rhododendron arboreum. Therefore, for the present study, the leaves of these two tree species were selected. In the field decomposition study, the following parameters were taken into account:
Litter bag technique (Bocock et al., 1960) was followed to study leaf litter decomposition in the field condition.
Isolation of bacteria from decomposing leaf litters
Dilution plate method (Johnson and Curl, 1972) was followed for the isolation of bacteria from decomposing leaf litters using Nutrient Agar (Difco-manual, 1953) medium.
Determination of moisture content and pH: Moisture content of the decomposing leaf litter was determined by drying 5 g of litter in a hot air oven at 60⁰C for 24 hours.
The percentage moisture was calculated as follows: W1- W2
Moisture content (%) = ------------- x 100