Significance of soil properties and microbial activity on soil co emission in coastal sand dunes of Odisha, India

Seasonal changes in soil respiration, soil temperature, soil moisture, soil organic carbon and microbial activity are compared between a barren sand dune without vegetation and sand dune with monoculture plantation of Casuarina equisetifolia (L.) of a coastal ecosystem. The result shows consistent patterns of change in CO₂ efflux rate and soil biotic and abiotic properties between barren sand dune and sand dune with monoculture plantation of Casuarina equisetifolia (L.). The abundance of fungi (Absidia glauca, Aspergillus awamori, Cladosporium cladosporioides, Curvularia eragrostidis, Drechslera australiensis, Fusarium oxysporum, Paecilomyces varioti, Penicillim citrinum, Rhizopus nigricans, Trichoderma viride) and bacteria increased significantly with plantation than the barren sand dune, and these differences in microbial community composition are strongly correlated with greater soil moisture and soil C content. The variation of soil CO₂ efflux rates is observed with soil properties and microbial activity and it is consistently higher in sand dune with vegetation than in barren sand dunes. Linear regression analysis revealed that soil respiration responses to changing biotic and abiotic factors are best predicted by soil moisture, soil organic carbon and microbial community composition in coastal ecosystem of Odisha. The result shows a significant and negative correlation between soil temperature and soil respiration. Additionally, no correlation is observed between soil moisture and soil temperature in both the sites. In contrast to the case for many other ecosystems, the relation of soil moisture and soil temperature failed to explain variations in respiration among the studied sites. The present study suggests that vegetation cover may alter the soil C balance in this ecosystem.