Diversity of Cyanobacteria in Chunkankadai Paddy Wetlands, Kanyakumari District, Tamilnadu, South India

Abstract

Algae are one of the major groups of soil microflora in agricultural lands. Among algae, the bluegreens are considered to be very valuable in agriculture. The role of them in soil fertility enhancement has been extensively studied worldwide. The Cyanobacteria (blue green algae) are a morphologically distinct group of oxygenic, photosynthetic organisms that inhabit terrestrial and aquatic ecosystems.  Sustainable utilization of an organism for any human purpose depends on how successfully the ecology of the same is thoroughly understood. Chunkankadai is a unique tropical paddy-wetland. Ecology of blue-green-algae and the exact diversity of the same in the zone remained unexplored. A rich blue-green-algal diversity of 33 species, is observed in these paddy-fields. The species richness and diversity index showed positive correlation to crop seasons. Apart from the specific soil and climatic factors, the total number of blue green algal isolates showed positive correlation to total nitrogen and phosphorus in the soils. The results of this experiment revealed that addition of Cyanobacteria as biofertilizer had significant effects on yield attributes of rice and soil properties. Finally, it might be concluded that the documentation on Cyanobacteria may enhance the understanding of the nutrient status of the field and might be applied for sustainable agricultural practices by reducing the application of chemical fertilizer to avoid the appearance of non-nitrogen fixers in the soil that might compete with nitrogen fixers for nutrients.