Harnessing and controlling algal blooms in rice ecosystem

Algal blooms are common phenomenon in wetland ecosystems, especially in shallow, warm and relatively still water, rich in nutrients. Bloom forming communities in rice ecosystem mainly consist of diverse green algae (Chlorella sp., Pandorina sp., Closterium sp. etc) and cyanobacteria species (Anabaena sp., Nostoc sp., Aulosira sp. etc) that take advantage of high levels of nitrogen and phosphorous in the rice fields. Early occurrence of algal blooms in wet-seeded rice (WSR) fields can adversely affect rice seedling emergence, tiller production, growth and productivity. Blue green algae, with their nitrogen fixing ability can be used as biofertilizer in improving rice growth. Algae in rice ecosystem also improve soil properties, produce a range of phytohormones and bio-stimulants, and provide resistance to both abiotic and biotic stresses. Microalgae in rice fields can be beneficial for increasing rice productivity and for mitigating environmental impacts. As global CO2 emissions rise, algae in rice fields can act as a viable alternative for mitigating climate change, with the ability to sequester carbon, simultaneously generating biomass for various applications. Excess algal growth can be prevented by physical removal, proper nutrient and water management, biomanipulation and use of algaecides. A balanced approach that harnesses the benefits and controls the risk of algal blooms can improve rice yield, reduce chemical input, and promote climate resilience in rice farming.