Author ORCID Identifier
https://orcid.org/0009-0001-6312-3417
Date Available
8-15-2025
Year of Publication
2024
Degree Name
Doctor of Philosophy (PhD)
Document Type
Doctoral Dissertation
College
Agriculture, Food and Environment
Department/School/Program
Plant and Soil Sciences
First Advisor
Cheng Qian
Abstract
Previous studies of the benefits of silicon (Si) supplementation in turfgrass have yielded inconsistent results. This dissertation aimed to assess the benefits if Si supplementation in cool-season turfgrass under more well controlled conditions than many previous studies. The first study assessed the effect of Si supplementation on biomass production and Si accumulation of tall fescue (Festuca arundinacea) and bentgrass (Agrostis stolonifera) in buffered Hoagland’s media (pH 6) with four sodium silicate (Na2SiO3) treatments (0, 0.5, 1, 2, and 4 mM Si). The two species responded differently to Si supplementation in terms of biomass. Bentgrass biomass was significantly enhanced (p < 0.05) only at 4 mM Si. Tall fescue showed significant biomass increase at 0.5, 1, and 2 mM Si, but not at 4 mM Si. There was a positive linear relationship between Si concentrations in media and aboveground tissue. Elevated Si promoted silica body formation, with the highest coverage at 4mM Si. Tall fescue benefits below 0.5 mM Si, while bentgrass benefits at 4 mM Si. The second study assessed the effects of different application methods (soil or foliar) with two different forms of Si (sodium silicate (Na2SiO3) or silica nanoparticles (SiO2-NPs)) on growth, soil plant analysis development (SPAD) value, and Si accumulation on tall fescue. Two experiments were performed in potting mix: EXP1-sodium silicate foliar or soil application; EXP2- foliar application of sodium silicate or SiO2-NPs. In addition, one experiment was performed in a 20:80 mixture of peatmoss to sand to reduce background dissolved Si in soil- EXP3 foliar and soil application with sodium silicate and SiO2-NPs. All Si treatments were applied at 8.5 mg Si/kg soil mass. SPAD value and dry biomass showed no differences across treatments. Sodium silicate (both foliar and soil applications) increased shoot Si but decreased root Si concentrations, suggesting that fertilization facilitates mobilization of Si from roots to shoots. Silica nanoparticles decreased shoot Si but increased root Si. Soil application resulted in greater Si uptake than foliar application. The last study assessed the effects of Si treatments (sodium silicate (Na2SiO3) or silica nanoparticles (SiO2- NPs)) on heat and drought stress tolerance. All Si treatments applied 76.5 mg Si/kg soil mass. Shoot Si accumulation enhanced under heat and drought stresses with sodium silicate but only under heat stress with SiO2-NPs. No benefits on growth or turf color were observed with Si treatments with or without stresses. Overall, this dissertation demonstrated potential benefits of Si supplementation in hydroponic systems for growth and silica body formation; however, benefits in pot studies, including under heat and drought stress, were not observed.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2024.345
Recommended Citation
Qian, Cheng, "SILICON FERTILIZATION IN COOL-SEASON TURFGRASSES" (2024). Theses and Dissertations--Plant and Soil Sciences. 184.
https://uknowledge.uky.edu/pss_etds/184
