LATE BLOOMER. Biofertilizers show return on investment only after sustained use over multiple seasons
| Photo Credit:
Pongsak Sapakdee
Today, agriculture faces pressure from soil degradation and the climate crisis. Our oceans can serve as a large laboratory for solutions to help plants withstand such stresses. Marine biotechnology, which has contributed significantly to the pharmaceutical sector, has the potential to disrupt the fertilizer and pesticide markets.
Prof Radhakrishnan Manikkam of the Centre for Drug Discovery and Development at Sathyabama Institute of Science and Technology says marine microbes hold promise in agricultural biotechnology. He has worked on isolating actinobacteria — the organisms responsible for numerous antibiotics — from environments that haven’t been fully explored, such as the deep sea. Unlike terrestrial microbes, the marine variants are adapted to survive highly saline environments, pressure and temperature, making them ideal catalysts for plant growth and stress resilience in crops.
In a paper titled ‘Plant growth promoting properties of marine bacteria, actinobacteria and fungi’, published under the compilation ‘Marine microbiome and microbial bioprospecting’, Manikkam refers to innovations such as synthetic microbial communities, where compatible microbes are “rationally assembled, as opposed to using just one strain — for example, one strain promotes plant growth, another helps fight pathogens, while yet another is tailored to counter environmental pollution”.
In a conversation with businessline, Manikkam says using microbes extracted from nature helps preserve land fertility, unlike chemical fertilizers that harm the soil.
He points out that microbes are used as fertilizers in Asian countries such as Thailand, China and Vietnam, where microbe-assisted organic farming systems are practised for high-value crops like durian and dates.
Marine microorganisms support agriculture through several direct and indirect mechanisms.
Marine microorganisms that promote plant growth act as natural biofertilizers. For instance, marine bacteria like Bacillus subtilis convert atmospheric nitrogen into ammonia, a form that plants can easily absorb. The microbes also make nutrients available to plants by secreting organic acids that solubilise insoluble phosphates. They enhance the availability of calcium and magnesium in the soil. Moreover, sea microbes produce phytohormones, which assist in root development and shoot elongation.
Key to soil health
They protect crops indirectly by producing siderophores, which make iron unavailable to pathogens, and secreting enzymes that degrade the cell wall of fungal pests. Research shows that certain strains derived from oceans, such as Pseudomonas fluorescens, can help suppress diseases such as wheat sheath blight. Compared to fast-acting chemicals, sea microbes work ‘slow but steady’ and help restore long-term soil health.
M Gomathy, an Associate Professor at the Tamil Nadu Agricultural University (TNAU), says lack of awareness and hesitancy of end-users are major hurdles in the progress of bio-innovation. At an international conference on ‘Microbial biotechnology for sustainable development in environment and agriculture’ organised recently by Sathyabama Institute, Gomathy said biofertilizers improve soil biological activity and nutrient-use efficiency over time. On the other hand, long-term intensive chemical use “may reduce soil organic carbon and microbial diversity”.
Also, biofertilizers take longer to show return on investment, requiring sustained use over multiple seasons. She added that organic inputs release nutrients gradually through microbial activity, improving nutrient retention and supporting soil microorganisms. The long-term economic incentive is significant, she pointed out. When used consistently, biofertilizers can reduce chemical fertilizer requirement by 15-30 per cent in several cropping systems. Further, organic certified products often fetch premium prices.
Despite the advantages, large-scale adoption remains a challenge. Though biofertilizers are supported under various government schemes that provide subsidies to small and medium farmers, usage is generally driven by ‘progressive and large farmers’ or village heads whose success with bio-agents, such as increased crop yields or latex yields in rubber estates, creates a ripple effect in the community.
Gomathy highlighted her team’s contribution in developing a yeast-based microbial consortium to enhance rice yield, which is being readied for technology release via TNAU. “Ongoing work includes a high-density liquid arbuscular mycorrhizal fungal (AMF) inoculum developed via root organ culture, which achieved more than 2 lakh propagules per ml,” she said.
The fungi enhance nutrient uptake, improve water-use efficiency and stress tolerance, and strengthen overall plant resilience.
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Published on February 23, 2026
