The Hydrological Fate Of Nutrients And Pesticides In The Urban Landscape In Response To Management And Lawn Species

Author : Amarilys Enid Gonzalez Vazquez
Publisher :
ISBN 13 :
Total Pages : 202 pages
Book Rating : 4.:/5 (132 download)

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Download or read book Impact of Seasonal Environmental Variations on 2,4-D Fate and Metabolism in Urban Landscapes written by Amarilys Enid Gonzalez Vazquez and published by . This book was released on 2021 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is one of the most commonly used herbicides on urban landscapes in the U.S. Although 2,4-D fate and breakdown have been well documented, interactions with the entire soil microbiome and simultaneous assessments of its transformation products (TPs) in urban soils remain poorly understood. Microorganisms, namely bacteria, are the primary drivers of pesticide transformation in the soil. Seasonal environmental variations are key factors that directly influence soil bacterial community structure and function, which may alter pesticide degradation networks resulting in the formation of TPs. This dissertation aimed to assess how varying seasonal conditions influenced the soil bacterial community, ultimately resulting in the degradation of 2,4-D and potential formation of its major TP, 2,4-dichlorophenol (2,4-DCP). Chapter 2 showed that 2,4-D was actively being degraded in urban soils at varying seasonal conditions, resulting in the formation of 2,4-DCP. Chapter 3 assessed shifts in the soil bacterial community at spring and summer conditions and how this influenced 2,4-D degradation. Overall, results from Chapter 3 tied with Chapter 2 suggest that bacteria shifted at varying seasonal conditions and were mainly involved in the degradation of 2,4-D in urban soils. In Chapter 4, the results suggest that 2,4-D breakdown activity in soil changes at different seasonal conditions, potentially resulting in TP formation in urban landscapes. However, a major finding in this study was that previously published PCR primers targeting the different gene classes resulted in non-specific amplification, leading to false-positive detection in soil samples. Chapter 5, a side study conducted in 2016, showed that translocation of the fungicide, propiconazole, was primarily limited to the lowest segment of the plant regardless of temperature or time following application. Together, results from this dissertation found that, indeed, negative impacts of pesticides do not end at the point of application. Seasonal environmental variations can shift the soil bacterial community, thus leading to the formation of 2,4-D's main TP, 2,4-DCP, in urban landscapes. which can behave differently in the environment. Altogether, all four chapters provide important information on the application of pesticides in turfgrass landscapes at varying seasonal conditions and their effect on non-target organisms. Ultimately, these findings will ensure better intensive plant and pest management strategies that provide landscapes of high quality with fewer non-target impacts on environmental and human health and enhance our overall understanding of pesticide fate and behavior.