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Progressing Forward: A New Dawn for Microbial Inoculants

By 26th September 2023No Comments

Progressing Forward: A New Dawn for Microbial Inoculants

 

Microbial Inoculants: The Future of Soil Enrichment

Our industry is substantially shifting towards more sustainable and effective management practices. Biological products are poised to play an instrumental role in this transformation. Several groundbreaking products are coming to market that exemplifies this trend. One of the promising developments includes the introduction of new microbial inoculants designed to enrich the soil with beneficial bacteria, helping the turf to access essential nutrients and enhancing their abiotic stress tolerance to drought and diseases while boosting overall growth and vitality (Madigan, et al, 2014).

Companion®:  A Paradigm Shift in Organic Microbial Inoculants

Companion® stands As a soil-amending microbial inoculant that aids in the breakdown of organic residues in the soil. It is an essential tool in a turf manager’s Integrated Pest Management (IPM) Programme. By populating the soil with these beneficial bacteria, Companion® is a liquid concentrate, necessitating dilution with water before application. It can be employed as a soil drench for root applications or as a foliar spray.

Modes of Action: Companion’s® efficacy can be attributed to several mechanisms:

  1. Colonisation: Bacillus species can outcompete detrimental microbes for resources by rapidly colonising the root zone.
  2. Plant Growth Promoting Rhizobacterium (PGPR) that stimulates rooting and better overall growth.
  3. Nutrient Cycling: Bacillus species can enhance plant nutrient uptake, with some strains solubilising phosphate for easier plant absorption.

Modes of Action: Plant Growth Promoting Rhizobacteria (PGPR) enhancing the health and vitality of turfgrass

The use of these beneficial bacteria can enhance the health and vitality of turfgrass, making it more resilient to stresses and reducing the need for chemical inputs (Santoyo,et al, 2022). Here is how their modes of action are utilised in turfgrass:

  1. Nitrogen Fixation: Since turfgrass requires substantial amounts of nitrogen for healthy growth, bacteria that fix atmospheric nitrogen can help fulfil this need without or with less reliance on synthetic nitrogen fertilisers (Klimasmith & Kent, 2022).

 

  1. Phosphate Solubilization: Phosphorus is another vital nutrient for turfgrass, particularly during the establishment phase. Bacteria that solubilise phosphate can enhance the availability of this nutrient, promoting faster establishment and more vigorous growth (de Andrade, et al, 2023).

 

  1. Producing Growth Hormones: Growth hormones can help improve turfgrass’ root depth and density, ensuring better nutrient uptake and resilience to various stresses (Aloo, etl al, 2022).

 

  1. Enhanced Root Growth: Increasing plant available nutrients to help improve root depth and density in turfgrasses, which ensures better nutrient uptake and resilience to various stresses. Healthier root growth leads to more resilient turfgrass that is more drought-tolerant and able to access water and nutrients from deeper soil layers. PGPR can promote such development (Vejan, et al, 2016).

 

  1. Stress Alleviation: Some bacteria can produce compounds or induce plant responses that mitigate the effects of salt stress, water stress, heat stress (Choudhury, et al, 2022).

 

  1. Siderophore Production: Siderophores chelate and transport essential micronutrients like iron to the plant. In turfgrass, this can enhance the green colour and overall appearance since iron plays a significant role in the production of chlorophyll (Rehan, et al, 2023).

 

  1. Carbon Cycling: Bacillus, like many microbes, plays a pivotal role in the decomposition of organic matter, thatch that accumulates around the crown, black layer and the release of CO2 through respiration. These processes are integral to the carbon cycle, ensuring the continuous flow and transformation of carbon in various forms (Malik, et, al, 2020).

 

  1. Soil flocculation: Microbially-mediated flocculation contributes significantly to soil health by improving its physical structure and promoting better water movement, aeration, and root growth. Furthermore, well-flocculated soils tend to provide a more conducive environment for diverse microbial communities (Zheng, et al. 2018). 

 

Deciphering Colony-Forming Units (CFUs): A Measure of Microbial Concentration

Imagine you are trying to count a vast crowd of people from a distance. It is challenging, right? In microbiology, we face a similar challenge when counting tiny bacteria or fungi. That is where the concept of Colony Forming Units (CFU) comes into play.

CFU is a method used to estimate the number of living bacteria or fungi in a sample. Think of it like this: if you give a single cell the right environment, it will grow and multiply into a visible group or “colony.” Each colony is believed to start from just one cell, hence the name “colony-forming unit” (Tortora, et al, 2018).

CFUs are a crucial metric in biological products for turf management because they estimate how many beneficial microbes you are applying to your turf. However, it is important to note that a higher CFU count does not necessarily mean a product is better. The effectiveness of a microbial product depends on many factors, including the specific strains of microbes used, the suitability of those microbes to the particular conditions on your turf, and the product’s overall formulation (Bhuyan, et al, 2022).

Microbes within Companion® are dormant when mixed with water. They become activated using the food source of carbon, which is abundant in all soil profiles. Especially ones that have a high organic matter content and high thatch content, along with any soil that is anaerobic soil and contains a black layer.

The advancements in biological products for nutrient management underscore the industry’s commitment to sustainable and effective practices. As research continues to unfold, these innovations are anticipated to set new benchmarks in turf management.

References

de Andrade, Luana Alves, Carlos Henrique Barbosa Santos, Edvan Teciano Frezarin, Luziane Ramos Sales, and Everlon Cid Rigobelo. (2023). “Plant Growth-Promoting Rhizobacteria for Sustainable Agricultural Production” Microorganisms 11, no. 4: 1088. https://doi.org/10.3390/microorganisms11041088

Choudhury, D., Tarafdar, S. . and Dutta, S. . (2022) “Plant growth promoting rhizobacteria (PGPR) and their eco-friendly strategies for plant growth regulation: a review”, Plant Science Today, 9(3), pp. 524–537. doi: 10.14719/pst.1604.

Bhuyan, S., Yadav, M., Giri, S. J., Begum, S., Das, S., Phukan, A., Priyadarshani, P., Sarkar, S., Jayswal, A., Kabyashree, K., Kumar, A., Mandal, M., & Ray, S. K. (2022). Microliter spotting and micro-colony observation: a rapid and simple approach for counting bacterial colony-forming units. DOI: 10.1101/2022.01.26.477842.

Isaac M. Klimasmith, Angela D. Kent, (2022) Micromanaging the nitrogen cycle in agroecosystems, Trends in Microbiology, Volume 30, Issue 11, Pages 1045-1055, ISSN 0966-842X, https://doi.org/10.1016/j.tim.2022.04.006. (https://www.sciencedirect.com/science/article/pii/S0966842X22001123)

Madigan, M. T., Martinko, J. M., Bender, K. S., Buckley, D. H., & Stahl, D. A. (2014). Brock Biology of Microorganisms (14th ed.). Pearson. ISBN: 978-0321897398. This textbook provides a comprehensive introduction to microbiology, including the concept of CFUs.

 

Malik, A.A., Martiny, J.B.H., Brodie, E.L. et al. (2020) Defining trait-based microbial strategies with consequences for soil carbon cycling under climate change. ISME J 14, 1–9 . https://doi.org/10.1038/s41396-019-0510-0

 

Rehan, Medhat, Ahmad Al-Turki, Adil H. A. Abdelmageed, Noha M. Abdelhameid, and Ayman F. Omar (2023). “Performance of Plant-Growth-Promoting Rhizobacteria (PGPR) Isolated from Sandy Soil on Growth of Tomato (Solanum lycopersicum L.)” Plants 12, no. 8: 1588. https://doi.org/10.3390/plants12081588

 

Santoyo, Gustavo, Carlos Alberto Urtis-Flores, Pedro Damián Loeza-Lara, Ma. del Carmen Orozco-Mosqueda, and Bernard R. Glick (2021). “Rhizosphere Colonization Determinants by Plant Growth-Promoting Rhizobacteria (PGPR)” Biology 10, no. 6: 475. https://doi.org/10.3390/biology10060475

 

Tortora, G. J., Funke, B. R., & Case, C. L. (2018). Microbiology: An Introduction. Pearson. ISBN: 978-0134605180. This textbook explains various techniques used in microbiology, including the usage of CFUs.

 

Vejan, Pravin, Rosazlin Abdullah, Tumirah Khadiran, Salmah Ismail, and Amru Nasrulhaq Boyce. (2016). “Role of Plant Growth Promoting Rhizobacteria in Agricultural Sustainability—A Review” Molecules 21, no. 5: 573. https://doi.org/10.3390/molecules21050573

 

Zheng, W., Zeng, S., Bais, H., LaManna, J. M., Hussey, D. S., Jacobson, D. L., et al. (2018). Plant Growth-Promoting Rhizobacteria (PGPR) reduce evaporation and increase soil water retention. Water Resources Research, 54, 3673–3687. https://doi.org/10.1029/2018WR022656.

 

Aloo Becky N., Tripathi Vishal, Makumba Billy A., Mbega Ernest R. (2022) Plant growth-promoting rhizobacterial biofertilizers for crop production: The past, present, and future Frontiers in Plant Science: Vol-13https://www.frontiersin.org/articles/10.3389/fpls.2022.1002448, DOI=10.3389/fpls.2022.1002448  ISSN=1664-462X