Date of Award

8-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Engineering and Earth Sciences

Committee Member

Dr. Haibo Liu, Committee Chair

Committee Member

Dr. Hong Luo

Committee Member

Dr. Sarah A. White

Abstract

Nickel (Ni) toxicity is becoming more prevalent in plants and soils due to increased applications of sewage sludge and waste water. New literature highlighting the Ni-tolerance of cool-season turfgrass species is needed. Herbicide resistant annual bluegrass (Poa annua L.) biotypes are also becoming more prevalent, stemming from application of single mode of action herbicides. Research was conducted to examine Ni tolerance of three cool-season turfgrasses and explore the possibility of Ni use as a suppressant of annual bluegrass. Seaside II creeping bentgrass (Agrostis stolonifera L.), PennLinks II creeping bentgrass (Agrostis stolonifera L.), and a weedy species mixture containing 61.4% annual bluegrass and 35.8% perennial ryegrass (Lolium perenne L.) were grown in pure sand and treated with six different Ni levels, supplied as NiSO4·6H2O (0, 200, 400, 800, 1600, and 3200 µg L-1 of Ni). The grasses were assessed based on turf quality, Normalized Difference Vegetation Index (NDVI), chlorophyll index, relative clipping biomass, relative root biomass, relative total biomass, and plant tissue Ni concentration. As Ni concentration increased, all parameters decreased and toxicity symptoms, followed by growth reductions, were observed for all three cool-season turfgrasses. At Ni concentrations of 400 and 800 µg L-1 the turf quality of Seaside II and PennLinks II was acceptable, but the turf quality of the weedy species was not acceptable. Seaside II turf quality was acceptable at 1600 µg L-1 Ni. At the study conclusion after exposure to 3200 µg L-1 Ni, PennLinks II and the weedy species were necrotic while Seaside II was actively growing with signs of yellowing. Cool season turfgrasses differ in their tolerance of exposure to Ni.

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