Role of fungi in litter decomposition associated with Casuarina equisetifolia L. plantations in coastal sand dunes, Orissa, India

摘要

Seasonal dynamics, of soil microfungal populations, their metabolic activity and decomposition of leaf litter were studied in a monoculture plantation of Casuarina equisetifolia L. in coastal sandy belt of Orissa for a period of 2 years (June 2002-May2004). Fungal succession of litter was also studied. Microbial isolation and soil analysis was performed using standard procedures and decomposition of leaf litter was studied using litter bag technique. Maximum population density was observed in the rainy season followed by winter and lastly summer. Larger microbial populations were encountered in plantation soil compared to barren sand, corresponding with the fluctuation of prevailing temperature, moisture and total organic carbon content. Rates of litter loss and carbon dioxide output followed the same trends as the population density. The annual K value was 0.41. The diversity index varied from 2.87 to 3.71 (Shannon) and 0.356 to 0.885 (Simpson). The similarity index showed that highly decomposedlitter (HDL) is more similar to Soil A (barren sand dune) than Soil B (sand dune with monoculture plantation of Casuarina). The introduction of predominantly decomposing microorganisms isolated from samples from the present study could help to increase the nutrient status of these soils. This research will hopefully improve the monitoring and management of decomposing fungi in the study area and highlights their importance in maintaining ecosystem services which could be a valuable tool for better understanding the long-term effects of changes in soil condition of the forest floors in coastal sand dunes of Orissa, India.