By Patricia Miller, PhDc & David Santos, MBiotech
As golf courses emerge from the winter season, spring green-up becomes a focal point for superintendents and turf managers. The success of this transition not only sets the stage for the course’s playing conditions throughout the year but also impacts the overall health of the turfgrass ecosystem for the season. A key player in this process is the microbial community present in both grass and the soil, along with their essential interactions. These microbiomes are vital for nutrient exchanges between grass and soil. They are composed of beneficial bacteria, as well as fungi, protozoa, and algae [1][2][3]. This blog dives into six different microbial activities in golf courses' spring green-up. It also provides practical implications for golf course management.
1. Microbial Influence on Nutrient Cycling
Microorganisms are essential for the release and cycling of nutrients within the soil. They break down organic matter into accessible forms for plants, releasing vital nutrients such as nitrogen, phosphorous, sulfur, iron, and more [1]. Grass then relies on its microbiome to access these soil nutrients from the rhizosphere, the zone of soil surrounding the roots. This interaction is significant during spring green-up, as the turfgrass comes out of dormancy and requires an influx of nutrients to support new growth in both tillers and roots [4].
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2. Disease Suppression and Plant Growth Promotion
Beneficial microbes play a role in suppressing pathogens and promoting plant growth. They degrade thatch, detoxify chemicals, and increase plant tolerance to various stresses, including diseases and pests [2]. Beneficial bacteria activate the grass plant’s immune system, enhancing disease resistance throughout the season. This biocontrol is crucial during the vulnerable phase of spring green-up when turfgrass is more susceptible to disease pressure and environmental stress [2][5].
3. Iron for Spring Green-Up
Iron plays a vital role in speeding the spring green-up process and is often deficient in the early spring due to high soil pH, low temperatures, excessive moisture, and soil compaction. This deficiency slows plant growth and increases disease pressure—these together slow spring green-up. Iron is also needed for other grass functions like chlorophyll production and is essential for the overall health of turfgrass [6]. Beneficial bacteria enhance the microbiome by producing siderophores, which access bound iron, increase its absorption by grass, and reduce bio-available iron for pathogens. This results in less pathogenic pressure and a healthier plant system that can grow earlier in the spring [7][8].
4. Soil Temperature and Microbial Activity
Soil temperature is a significant factor in microbial activity and turfgrass growth. As soil temperatures rise above 50 degrees Fahrenheit, microbial activity increases, spurring the release of nutrients and aiding in the transition from dormancy to active growth [4]. This relationship underscores soil temperature’s importance in microbial and plant life cycles. Temperature also affects the transition of Bermudagrass green-up from winter cool-season overseeded grass in warmer climates. Nitrogen fertilizers should be minimized in temperatures below 50° F (10° C) to prevent cool-season grass growth. Bermudagrass relies on nitrogen storage from the previous season during this transition. Bacterial nitrogen fixation in a healthy soil and grass microbiome will be vital to this transition, especially in the first two weeks of spring green-up [6].
5. Microbial Diversity and Turf Health
Research has shown that microbial diversity is associated with turf health. A diverse microbial community can thrive under healthy management practices, and organic or low-input practices may enhance soil disease suppressiveness [2]. Management strategies that support microbial diversity can lead to a healthier and more resilient turfgrass and soil that can better resist bacterial and fungal pathogens and drought, temperature, and salinity stress [7].
6. Microbial Products and Inoculants
Microbial products and inoculants are gaining traction as a sustainable approach to turf management. These natural products can improve soil microbial activity, increase nutrient uptake like iron and nitrogen, provide plant resistance to colder temperatures, and enhance plant resilience to other environmental stressors [9]. By incorporating beneficial microorganisms into turf roots and soil, golf courses can reduce reliance on chemical fertilizers and pesticides and promote a healthier and more sustainable environment [9][10]. Microbial inoculants also shift the grass microbiome to an active state of resistance to stress, and this is a crucial component of reducing the impact of disease, drought, and salinity on your turf [11]. Look at our blog, Microbials and Golf Turf, for a deeper dive into this topic.
Practical Implications for Golf Course Management
For golf course superintendents, understanding and improving microbial activity is essential for successful spring green-up and year-round turf health. Organic fertilization, aeration, and proper irrigation can support a vibrant microbial community [4][5]. Monitoring soil temperature, pH, and moisture levels can also help optimize conditions for microbial life and turfgrass growth[4]. In zones where grass is overseeded, nitrogen fertilizers should be kept to a minimum to ensure a successful transition, and this is where microbiome supplementation has a high impact [6].
In conclusion, microbial diversity and activity are cornerstones of a successful spring green-up for golf courses. By fostering a healthy microbial community, superintendents can ensure that their turfgrass has access to the necessary nutrients, enjoys natural disease suppression, and is resilient against environmental stress. This benefits the immediate appearance and playability of the course and contributes to the turfgrass ecosystem’s long-term health and success.
Citations:
[1] Hoorman, J. J., & Islam, R. (n.d.). Understanding Soil Microbes and Nutrient Recycling. Ohio State University Extension. Retrieved from https://ohioline.osu.edu/factsheet/sag-16
[2] Meena, M., Swapnil, P., Zehra, A., Aamir, M., Dubey, M., Goutam, J., & Upadhyay, R. (2017). Beneficial Microbes for Disease Suppression and Plant Growth Promotion. In Advances in Plant Microbiome and Sustainable Agriculture (pp. 303-320). Springer. https://doi.org/10.1007/978-981-10-6593-4_16
[3] Bhatti, A. A., Haq, S., & Bhat, R. A. (2017). Actinomycetes benefaction role in soil and plant health. Microbial Pathogenesis, 111, 458–467. https://doi.org/10.1016/j.micpath.2017.09.036
[4] Carey, R. O., Hochmuth, G. J., Martinez, C. J., Boyer, T. H., Nair, V. D., Shober, A. L., Cisar, J. L., Trenholm, L. E., & others. (2012). A Review of Turfgrass Fertilizer Management Practices: Implications for Urban Water Quality. HortTechnology, 22(3), 280-291. https://journals.ashs.org/horttech/view/journals/horttech/22/3/article-p280.xml
[5] Cooper, R. J. (1996, November). Soil microorganisms: A turf manager’s guide. GCMOnline. Retrieved from https://gcmonline.com/course/environment/news/soil-microorganisms-soil-microbes-turfgrass.
[6] Duble, R. L. (n.d.). Spring Transition in Bermudagrass. Texas Cooperative Extension. Retrieved from https://aggie-hort.tamu.edu/plantanswers/turf/publications/spring.html
[7] Mackiewicz-Walec, E., & Olszewska, M. (2023). Biostimulants in the Production of Forage Grasses and Turfgrasses. Agriculture, 13(9), 1796. https://doi.org/10.3390/agriculture13091796
[8] Sultana, S., Alam, S., & Karim, M. M. (2021). Screening of siderophore-producing salt-tolerant rhizobacteria suitable for supporting plant growth in saline soils with iron limitation. Journal of Agriculture and Food Research, 4, 100150. https://doi.org/10.1016/j.jafr.2021.100150.
[9] Pennisi, S. V., Habteselassie, M., Kostandini, G., & Waltz Jr., F. C. (2022). Familiarity and Use of Biostimulants by the Georgia Golf Industry: Information from a Survey of Golf Course Superintendents. HortTechnology, 32(4). https://journals.ashs.org/horttech/view/journals/horttech/32/4/article-p382.xml#:~:text=URL%3A%20https%3A%2F%2Fjournals.ashs.org%2Fhorttech%2Fview%2Fjournals%2Fhorttech%2F32%2F4%2Farticle
[10] Stingl, U., Choi, C. J., Dhillon, B., & Schiavon, M. (2022). The Lack of Knowledge on the Microbiome of Golf Turfgrasses Impedes the Development of Successful Microbial Products. Agronomy, 12(1), 71. https://doi.org/10.3390/agronomy12010071
[11] Wei, H., He, W., Li, Z., Ge, L., Zhang, J., & Liu, T. (2022). Salt-tolerant endophytic bacterium Enterobacter ludwigii B30 enhance bermudagrass growth under salt stress by modulating plant physiology and changing rhizosphere and root bacterial community. Frontiers in Plant Science, 13, 959427. https://www.frontiersin.org/articles/10.3389/fpls.2022.959427/full.
An older version of this blog can be found here: https://www.earthmicrobial.com/blogs/golf/microbial-activity-spring-green-up