Culturable Soil Fungal Diversity and Agroecosystem Ecology in Lateritic and Alluvial Zones of West Bengal, India: A Comparative Study of Agricultural and Garden Soils

Abstract

Aim: The present study aimed to assess and compare culturable soil fungal diversity, abundance, evenness, and dominance pattern in agricultural and garden soils of two contrasting agro-ecological zones of West Bengal, India. Study Design: The study was designed as a comparative ecological assessment of soil fungal communities across two soil types, namely lateritic soil and alluvial soil, and two land-use conditions, namely agricultural soil and garden soil. Place and Duration of the Study: The study was carried out in selected sites of Purulia district, representing the lateritic soil zone, and Hooghly district, representing the alluvial soil zone of West Bengal. Soil samples were collected during the main paddy cultivation period in June and August. Methodology: Rhizospheric soil samples were collected from agricultural and garden soils of both lateritic and alluvial zones. Fungi were isolated from the collected soil samples and identified based on colony characters and microscopic features. The number of fungal colonies was recorded for each taxon. Species richness, total abundance, Shannon diversity index, evenness, Simpson index of diversity, and Berger-Parker dominance index were used to compare fungal community structure among the four soil categories. Results: A total of 22 culturable fungal morphotypes were recorded from the studied soils. The major recorded genera included Penicillium, Aspergillus, Rhizopus, Trichoderma, Fusarium, Mucor, Curvularia, Bipolaris, Cladosporium, and Cunninghamella. Total fungal colony abundance was higher in garden soil than agricultural soil in both zones. In lateritic soil, garden soil recorded 586 colonies, while agricultural soil recorded 320 colonies. In alluvial soil, garden soil recorded 728 colonies, while agricultural soil recorded 404 colonies. Shannon diversity was also higher in garden soils, with values of 2.477 in lateritic garden soil and 2.606 in alluvial garden soil, compared to 2.011 and 2.18 in lateritic and alluvial agricultural soils respectively. Berger-Parker dominance was lower in garden soils, indicating a more balanced fungal community structure than agricultural soils. Conclusion: The study indicates that garden soils support higher culturable fungal abundance and diversity than agricultural soils in both lateritic and alluvial agro-ecological zones. Alluvial garden soil showed the highest fungal abundance and Shannon diversity, while lateritic agricultural soil showed the lowest values. The lower dominance values in garden soils suggest better community balance and greater fungal heterogeneity. Therefore, soil fungal diversity can be used as an important ecological indicator for assessing soil biological condition and agroecosystem health in contrasting soil zones of West Bengal.