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Azolla and its symbiotic Anabaena azollae
Source publication
Azolla is a fast growing free floating freshwater fern which fixes atmospheric nitrogen by forming a symbiotic association with a prokaryotic cyanobacterium -Anabaena azollae. It is a costeffective, eco-friendly biofertilizer in lowland rice fields. As green manure in water logged soil, it enhances the rapid mineralization of nitrogen, improves the...
Contexts in source publication
Context 1
... forms a symbiotic association with the prokaryotic blue-green alga Anabaena azollae (Figure 1). In this association, the eukaryotic partner Azolla provides shelterto the cyanobacterium Anabaena azollae in its leaf cavities and also supplies carbon source. ...
Context 2
... Anabaena azollae is a prokaryotic cell containing three types of cells-vegetative cells, heterocysts and akinetes (Figure 1). The vegetative cells are highly pigmented whereas heterocysts are large, thick walled, lightly pigmented cells and the average heterocyst frequency is 7 to 20 %. ...
Citations
... Farmers can manage around 30-60 kg N by incorporating Azolla at the rate of 16000 kg ha -1 in rice crops instead of supplying through N fertilizers, given the sustainability of soil health (Samal et al., 2020;Sanjay and Singh, 2020). A group researchers reported that symbiosis between Azolla and cyanobacteria supplied 30-60 kg ha -1 N fixation (Kollah et al., 2016). ...
... An increase in grain yields of rice from 14 -40% has been reported, with Azolla being used as a dual crop and by 15-20 % being monocropping during the fallow season (Samal et al., 2020). A group researcher had reported the highest rice grain yield when the application of Azolla compost at 5.0% of soil weight, which was on average 13.8% higher than that of the non-amended control (Razavipour et al., 2018). ...
Rice is the staple food for the significant population of Asia. Due to projected population growth in this region, the demand for this food is also predicted to be increased exponentially soon. Nitrogen (N) plays a dominant role in increasing rice yield as it is the most critical yield-limiting nutrient of rice. Chemical N fertilizers which are a major source in supplying N nutrients to rice, have adverse effects on overall soil and environmental health in the long term. The application of free-floating aquatic fern Azolla as a biofertilizer can be an alternative to improve rice yield without degrading the environment. It provides a natural source of many nutrients, especially N, improves the availability of other nutrients, plays a critical role in weed suppression, enhances soil organic matter, and improves efficiency of the inorganic fertilizers while maintaining the suitable soil pH condition for rice growth, which overall contribute to rice yield increment. Therefore, Azolla application has tremendous potential to improve soil health and boost yield sustainability.