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Explora: Environment
and Resource Anabaena-Azolla for crops and bioenergy

for biomass production in natural ecosystems. Soluble and actinomycetes as well as increased enzyme activity,
phosphate constantly moves from terrestrial to aquatic which improved the soil’s nutrient recycling ability.
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habitats in a single direction, and most organic phosphates Macronutrients and other minerals that reduce rice
are not bioavailable to many species. Moreover, most production include potassium and phosphorus. In low
phosphates are found immobilized as calcium and iron potassium environments, Azolla is particularly effective
salts. These nutrients are typically provided to crops at accumulating potassium in its tissues. After field water
in the form of chemical fertilizers. 80,81 In addition, it is drained, Azolla decomposes quickly, releasing nutrients
has been suggested that cyanobacteria can increase the like nitrogen, phosphorous, and potassium into the soil.
bioavailability of phosphorus for plants using phosphatase It also releases certain compounds, such as plant growth
enzymes to mobilize and solubilize insoluble organic regulators and vitamins, that enhance the growth of rice
phosphates. They achieve this by producing a calcium crops and solubilizes magnesium, iron, and zinc, making
3
ion chelator that dissolves phosphate compounds while these nutrients available to the rice crop. The availability
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maintaining the pH of the growth medium. The following of soil nutrients is further boosted by its constant
reactions release organic acids to solubilize the phosphate application. In general, Azolla applications increase
compounds: 77 the biological activity of the soil, which promotes the
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+2
Ca (OH) (PO ) → 10Ca + 6PO 3- (II) development of microflora necessary for mineralization.
10 2 4 6 4 Organic compounds broken down during mineralization
Ca (PO ) + 2H CO → 2CaHPO + Ca(HCO ) (III) release nutrients into the soil. It has been speculated
3 4 2 2 3 4 3 2
Furthermore, the excretion of extracellular phosphatases that the growth of cyanobacteria in flooded rice fields
and organic acids is a major mechanism through which influences the forms of soil-bound iron, magnesium,
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cyanobacteria contribute to the mobilization of inorganic and possibly zinc. The presence of these organisms
phosphates in agricultural fields. This process makes increased the levels of other forms of Fe and manganese
2
phosphate more easily dissolved and mineralized, whereas decreasing the amount of ammonium acetate-
converting it into easily obtainable soluble organic extractable forms of these elements. These changes are
phosphates or orthophosphates. 3 thought to result from increased organic matter, especially
extracellular material, and the release of O . 39
2
7. Influence of Anabaena-Azollae and The use of cyanobacteria has improved the quality of the
cyanobacteria on soil enrichment soil by preserving soil moisture, organic matter, nitrogen,
1
It has been demonstrated that the Azolla-Anabaena and phosphorus. The mucilaginous substance produced
symbiosis enhances the nutrient content, water retention by decomposing cyanobacteria functions as a binding
capacity, porosity, and cation exchangeability of soil. agent for the soil, increasing its humus content and making
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3
Azolla compost enhances the organic matter in the soil it more suitable for the growth of other plants. Biological
and provides a positive effect on plant development and soil crusts are degraded by anthropogenic and natural
output, offering benefits over uncooked, under-rotted disturbances, and full regeneration of such crusts under
organic waste and synthetic fertilizers. The rise in organic natural circumstances can take decades. Nevertheless, the
2
C is partly caused by the high organic carbon content of introduction of cyanobacteria significantly accelerates the
Azolla. Approximately 90% of Azolla reportedly decays healing process, and biological crusts akin to those found
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within 4 weeks. In a short period, the Azolla absorbed in arid and semiarid areas of the globe are essential for
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by the soil mineralizes, producing humic compounds, preserving and revitalizing regional ecology. Anabaena
which in turn contribute to the soil’s organic carbon level. doliolum, Allocasuarina torulosa, Nostoc carneum, Nostoc
According to previous research, adding Azolla enhances piscinale, Oscillatoria, Plectonema, Schizothrix, and
1
the organic content and rate of soil mineralization. It was other cyanobacterial strains work together to enhance
found that inoculating Azolla increased the soil’s organic soil microbial biomass, carbon, nitrogen, and humus
carbon level. Research by a particular group indicated that content, all of which help retain moisture and promote
combining Azolla with cow manure enhanced the organic soil formation. Extracellular polymeric substances
carbon level of the soil by 1.3 – 1.7%. Similarly, it was produced by cyanobacteria increase the water-holding
noted that soil treated with Azolla had a 25.51% increase capacity. Cyanobacterial consortia, in combination with
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in oxidizable organic carbon. Other studies have shown different rhizosphere bacteria, have shown significant
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a significant increase in the population of heterotrophic improvements in soil fertility and crop yield, as their
bacteria, along with enhanced cellulolytic and urea- efficacy in micronutrient enrichment and carbon-
hydrolyzing activity. Similar to this, a study found that soil nitrogen sequestration in soil for rice-wheat cropping
with added Azolla had higher levels of bacteria, fungus, systems. 2

Volume 2 Issue 2 (2025) 9 doi: 10.36922/eer.7975