The Environmental and Health Effects of Emerging Agricultural Techniques Restricted; Files Only

Peters, Samuel (Spring 2019)

Permanent URL: https://etd.library.emory.edu/concern/etds/6969z203r?locale=pt-BR
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Abstract

As we strive to discover new ways of producing food for a growing and urbanizing population, we need to assess the impacts of these emerging systems on the environment and health. The first study of this dissertation analyzed the soil greenhouse gas (GHG) and ammonia (NH3) fluxes in a living mulch system compared to three other conventional systems to understand the differences and potential soil parameters driving them. Carbon dioxide (CO2), nitrous oxide, and NH3 fluxes were higher between rows of corn in living mulch plots compared to other systems, influenced partially by soil moisture, temperature and nitrogen compounds. Increased soil organic carbon in living mulch plots indicated an overall sink for carbon. The second study measured the same soil trace gases in corn with five nitrogen sources including cowpea intercropping and biochar amended systems and calculated a net carbon equivalent (CE) for each system accounting for other agricultural inputs. CO2 fluxes and net CE were higher in intercropping and urea fertilizer plots when controlling for soil moisture and temperature. CO2 and NH3 fluxes were lower in plots with biochar compared to those without. Plots with biochar had lower net CE, until accounting for the production of biochar, indicating the importance of assessing agriculture wholistic to understand the overall impacts. The final study used community engaged research (CER) to assess heavy metal soil concentrations in Atlanta urban agricultural and residential sites under two different risk frameworks. Most samples were below Environmental Protection Agency regional screening levels, but several sites were above University of Georgia low risk levels, indicating potential changes in risk depending on the framework used. This study also indicated some best practices to reducing concentrations below low risk levels in both frameworks. Finally, through community and regulatory partnerships, this study led to the discovery and subsequent cleanup of a residential lot with illegally dumped slag, indicating the potential of CER to create direct impacts on environmental justice issues. Each of these studies highlights the tradeoffs that sometimes exist between the benefits of emerging agricultural systems and impacts on the environment and health.

Table of Contents

CHAPTER 1: INTRODUCTION…………………………………………………………………1

           DISSERTATION AIMS…………………………………………………………………..8

CHAPTER 2…………………………………………………………………………………….....9

ABSTRACT……………………………………………………………………………...10

KEY TERMS AND ABBREVIATIONS………………………………………………...11 INTRODUCTION……………………………………………………………………….12

METHODS………………………………………………………………………………14

RESULTS………………………………………………………………………………..21

DISCUSSION……………………………………………………………………………24

CONCLUSION…………………………………………………………………………..27

           TABLES AND FIGURES………………………………………………………………..29

           SUPPLEMENTAL MATERIALS…………………………………………………….…36

CHAPTER 3…………………………………………………………………………………...…43

ABSTRACT……………………………………………………………………………...44

           KEY TERMS AND ABBREVIATIONS………………………………………………...45

INTRODUCTION……………………………………………………………………….46

METHODS………………………………………………………………………………49

RESULTS………………………………………………………………………………..55

DISCUSSION……………………………………………………………………………58

CONCLUSION…………………………………………………………………………..63

           TABLES AND FIGURES………………………………………………………………..65

           SUPPLEMENTAL MATERIALS……………………………………………………….71

CHAPTER 4…………………………………………………………………………………...…77

ABSTRACT…………………………………………………………………………...…78

           KEY TERMS AND ABBREVIATIONS……………………………………………...…79

INTRODUCTION……………………………………………………………………….80

METHODS………………………………………………………………………………82           

RESULTS AND DISCUSSION…………………………………………………………84

           TABLES AND FIGURES………………………………………………………………..92

CHAPTER 5: CONCLUSIONS………………………………………………………………...100

WORKS CITED………………………………………………………………………………...106

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