University of Washington’s Sustainability Research:
Increasing the drought tolerance and nitrogen efficiency of the lawns on campus
In the United States turf grass has an estimated surface area three times greater than any other irrigated crop (163,812 km^2). Establishment and maintenance of turf grass require high inputs, especially in regard to nitrogen and water (Milesi et al., 1995). Chemical fertilizers can be detrimental to the environment and to the long term health of soils. With global warming at the forefront of scientific research, it is imperative that alternative, environmentally friendly lawn care systems are implemented.
The University of Washington has over 161 acres of turf grass. Grounds maintenance, at the University applies a custom, slow release nitrogen fertilizer (F-6 Wil-Grow Wil-Cote Custom-CFM 25-0-5) for all turf applications. In 2015, 8,620 pounds of fertilizer were applied on campus. We are looking into the possibility of lowering this number as well as increasing its sustainability practices. Currently, one of the main goals of ground management is to review ways that can decrease the carbon footprint of the University. Revising the fertilizer plan for the lawns is a potentially important step for grounds management to undertake.
Endophytes, micro-organisms that live within plants, have the potential to lower the need for these chemical fertilizers. Two ways that endophytes can accomplish this are by fixing nitrogen and by producing plant growth hormones. Nitrogen gas is the main constituent of the atmosphere, but it is unattainable by plants in its gas form. Endophytes are able to convert this atmospheric dinitrogen gas into ammonium, a usable plant product (Knoth, Kim, Ettl, & Doty, 2014). Endophytes can also decrease the need for chemical fertilizers by producing the plant growth hormones indole acetic acid (Beyeler, Keel, Michaux, & Haas, 1999), and cytokinin (Timmusk, Nicander, Granhall, & Tillberg, 1999).
This research attempts to quantify the effects of endophytes on turf grass in the field. Biomass, photosynthesis, weed suppression, leaf color, and drought tolerance will be measured. After the research is completed, an evaluation will be conducted to assess whether the inoculation of the campus lawns with endophytes is a viable replacement for the current chemical fertilizer plan at the University of Washington.
In the greenhouse, water stressed perennial rye grasses inoculated with endophytes were taller, stayed green and lived for longer than the non-inoculated control. The inoculated plants had 60% higher root and 48% higher shoot biomass than the non-inoculated control (Khan, Guelich, Phan, Redman, & Doty, 2012). A wild poplar (Populus trichocarpa) endophytic bacterium (WPB) was found to have an enzyme, nitrogenase, that is associated with nitrogen fixation. WPB inoculated and non-inoculated Kentucky bluegrass were grown in nitrogen-free mediums. The inoculated plants had 42% more dry weight and 37% more nitrogen than the non-inoculated control (Xin, Zhang, Kang, Staley, & Doty, 2009).
Materials and Methods:
This research will focus on answering the following questions about the effects of endophytes on turf grass: 1) What would be the economic and environmental costs for the University of Washington to inoculate their turf grass with endophytes? 2) Does endophyte inoculations effect the health and growth of turf grass? 3) Does endophytes inoculations help to suppress weed growth? 4) Does endophyte inoculations increase drought tolerance?
There will be ten different treatments looking at the effects of applying endophytes on the lawns on campus. Each treatment will be completed in a 3’ by 3’ plot. Plots will be established at the Center for Urban Horticulture. If needed plots will be hand weeded and seeded in the spring of 2017. Scotts Sun and Shade mix, the turf grass used on campus, will be utilized in this study. Endophytes will be applied using a back-pack sprayer immediately after mowing.
Budget and Timeline:
The research will begin in the spring of 2017. The majority of the 1000 dollars will be applied to hiring a student intern to establish the plots and take measurements throughout the year. Around 50 dollars will be spent on media to grow the endophytes on. The project will be undertaken for around two to three years. If the research shows promise we will apply for a new grant and grounds management will apply endophytes onto the lawns throughout the entire campus. Thousands of gallons of water and thousands of pounds of fertilizer could potentially be saved from being applied to the lawns.
Beyeler, M., Keel, C., Michaux, P., & Haas, D. (1999). Enhanced production of indole-3-acetic acid by a genetically modi ¢ ed strain of Pseudomonas £ uorescens CHA0 a ¡ ects root growth of cucumber , but does not improve protection of the plant against Pythium root rot. FEMS Microbiology Ecology, 28, 225–233.
Khan, Z., Guelich, G., Phan, H., Redman, R., & Doty, S. (2012). Bacterial and Yeast Endophytes from Poplar and Willow Promote Growth in Crop Plants and Grasses. ISRN Agronomy, 2012, 1–11. http://doi.org/10.5402/2012/890280
Knoth, J. L., Kim, S. H., Ettl, G. J., & Doty, S. L. (2014). Biological nitrogen fixation and biomass accumulation within poplar clones as a result of inoculations with diazotrophic endophyte consortia. New Phytologist, 201(2), 599–609. http://doi.org/10.1111/nph.12536
Milesi, C., Elvidge, C. D., Dietz, J. B., Tuttle, B. T., Nemani, R. R., & Running, S. W. (1995). a Strategy for Mapping and Modeling the Ecological Effects of Us Lawns.
Timmusk, S., Nicander, B., Granhall, U., & Tillberg, E. (1999). Cytokinin production by Paenibacillus polymyxa. Soil Biology and Biochemistry, 31(13), 1847–1852. http://doi.org/10.1016/S0038-0717(99)00113-3
Xin, G., Zhang, G., Kang, J. W., Staley, J. T., & Doty, S. L. (2009). A diazotrophic, indole-3-acetic acid-producing endophyte from wild cottonwood. Biology and Fertility of Soils, 45(6), 669–674. http://doi.org/10.1007/s00374-009-0377-8
Thank you for your consideration!
Ph.D. Student, School of Environmental and Forest Sciences
Center for Urban Horticulture, University of Washington
Integrated Pest Management and Sustainability Coordinator: Grounds Management