Action and roles of biofertilizers

1. Action and Roles of Biofertilizers
in Agriculture
Presented by,
Nabin Dahal
dnabin563@gmail.com
Roll No.: 02
MSc First Semester
Central Department of Botany, Tribhuvan University
Image Source: https://www.resetagri.in/blogs/fertilizer-
management/farmer-must-know-this-before-using-biofertilizers
30 June 2023 1

2. Increase in food demand with growing population
Essential to increase crop productivity
Extensive use of chemical fertilizers
Biofertilizers as an alternative of agro-chemicals for
sustainable agriculture
Adverse effect on soil health and ecological balance
between microflora and environment, health hazards
Introduction
( Ghany et al., 2013; Singh et al., 2014; Nedunchezhijan
et al., 2018; Ortiz & Sansinenea, 2022) 2

3. Introduction…
 Biofertilizers/microbial inoculants, preparations of living micro-organisms,
applied to seed, soil or plant surfaces for better availability of nutrients to plants
(Khosro and Yousef, 2012)
Image source: https://doi.org/10.3389/fpls.2022.930340
Figure 1. Classification of Biofertilizers
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4. i) Direct Mechanisms: Supplying mineral nutrients and promoting growth
ii) Indirect Mechanisms: Protection from biotic (pathogens) and abiotic stress
(Daniel et al., 2022)
Action of Biofertilizers
Image source: https://en.wikipedia.org/wiki/Arbuscular_mycorrhiza
Image source: https://doi.org/10.3390/microorganisms10061220
Figure 2. Action of PGPR Figure 3. Action of AMF
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5. Action of Biofertilizers…
• Nitrogen Fixation: Conversion of atmospheric Nitrogen to ammonia, carried out
by free living bacteria, symbiotic bacteria, cyanobacteria (Daniel et al., 2022)
Image source: https://doi.org/10.3390/microorganisms10061220
Figure 4. Process of Nitrogen Fixation
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6. Action of Biofertilizers…
• Phosphate Solubilization: By PGPR like Pseudomonas, Bacillus, Rhizobium,
organic acids like citric and gluconic acids are responsible for phosphorous
solubilization (Daniel et al., 2022)
Image source: https://doi.org/10.3390/microorganisms10061220
Figure 5. Process of Phosphate Solubilization 6

7. Action of Biofertilizers…
• Siderophores Formation: Iron chelating compounds, secreted by bacteria, supply
Iron (Fe 2+) (Daniel et al., 2022)
Image source: https://doi.org/10.3390/microorganisms10061220
Figure 6. Process of Iron absorption by Siderophores formations
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8. Roles of Biofertilizers in Agriculture
i) Crop productivity and plant growth;
• Increased nourishment and uptake of mineral nutrients (N, P, K, Zn, Cu etc.)
(Anand et al., 2022)
• Mobilization and recycling of soil nutrients, improving soil quality, secretion of
phytohormones (Ortiz & Sansinenea, 2022)
• Can increase crop yield by 10-50 % (Ghany et al., 2013)
ii) Tolerance against biotic (phytopathogens) and abiotic stresses;
• Against biotic stresses (phytopathogens) – Biofertilizers as biocontrol agents
(Hernández-Fernández et al., 2021), Induced Systemic Resistance (ISR),
antagonistic to pathogens (Bacillus subtilis, Trichoderma harzianum for Fusarium
root rot of tomato) (Anand et al., 2022) 8

9. Roles of Biofertilizers in Agriculture…
• Against abiotic stresses- Climate change driven increasing abiotic stresses like
drought, salinity, waterlogging, heavy metals and excessive heat (He et al.,
2018), biofertilizers provide tolerance against abiotic stresses by secretion of
siderophores, phytohormones like IAA and HCN with improved root growth
(Chaudhary et al., 2021),
iii) Food security and food safety:
• Low cost and eco-friendly, increased crop production with high quality nutrients,
ensure sustainable agriculture, availability and accessibility of safe and
nutritious food to people (Daniel et al., 2022)
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10. Image source: https://doi.org/10.3389/fpls.2022.930340
Figure 7. Role of biofertilizers in crop productivity and
tolerance against stresses
Roles of Biofertilizers in Agriculture…
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11. Conclusion
• Biofertilizers/microbial inoculants provide essential mineral nutrients to plants by
the process of biological nitrogen fixation, phosphorous and potassium
solubilization, siderophores formation etc.
• Biofertilizers are economically effective and ecofriendly (safe to use) products that
through the availability of mineral nutrients to the plants, increase crop
productivity, improve soil fertility and promote plant growth and development.
• Biofertilizers are the best alternative to chemical based synthetic fertilizers for
ensuring food security to increasing global population.
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12. References
Anand, K., Pandey, G. K., Kaur, T., Pericak, O., Olson, C., Mohan, R., … Yadav,
A. N. (2022). Arbuscular mycorrhizal fungi as a potential biofertilizers for
agricultural sustainability. Journal of Applied Biology & Biotechnology, 10, 90–
107. doi:10.7324/jabb.2022.10s111
Chaudhary, P., Singh, S., Chaudhary, A., Sharma, A., & Kumar, G. (2022a).
Overview of biofertilizers in crop production and stress management for
sustainable agriculture. Frontiers in Plant Science, 13, 930340.
Daniel, A. I., Fadaka, A. O., Gokul, A., Bakare, O. O., Aina, O., Fisher, S., … Klein,
A. (2022). Biofertilizer: The Future of Food Security and Food Safety.
Microorganisms, 10(6), 1220. doi:10.3390/microorganisms10061220
Ghany, T. M. A., Alawalaqi, M. M., & Abboud, M. A. A. (2013). Role of biofertilizers
in agriculture: a brief review. Mycopath, 11(2), 95–101.
He, M., He, C., & Ding, N. (2018). Abiotic stresses: General defenses of land
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plants and chances for engineering multistress tolerance. Frontiers in Plant
Science, 9. doi:10.3389/fpls.2018.01771
Hernández-Fernández, M., Cordero-Bueso, G., Ruiz-Muñoz, M., & Cantoral, J. M.
(2021). Culturable yeasts as biofertilizers and biopesticides for a sustainable
agriculture: A comprehensive review. Plants, 10(5), 822.
doi:10.3390/plants10050822
Khosro, M., & Yousef S. (2012). Bacterial biofertilizers for sustainable crop
production: A review. ARPN Journal of Agricultural and Biological Sciences, 7,
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Nedunchezhijan, M., Laxminarayana, K., & Chauhan, V. B.S. (2018). Soil microbial
activities and yield of elephant foot yam as influenced by weed management
practices in alfisols. International Journal of Vegetable Science, 24(6), 583–
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Ortiz, A., & Sansinenea, E. (2022a). The role of beneficial microorganisms in soil
quality and Plant Health. Sustainability, 14(9), 5358. doi:10.3390/su14095358
Singh, V., Shakywar, R.C., Dubey, R.K., Chauhan, V.B.S. (2014). Management of
Taphrina leaf spot of Turmeric under Arunachal Pradesh Condition. Annals of
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