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Validating Nitrogen Requirements for Florida Landscape Plants

Permanent Link: http://ufdc.ufl.edu/UFE0042612/00001

Material Information

Title: Validating Nitrogen Requirements for Florida Landscape Plants
Physical Description: 1 online resource (192 p.)
Language: english
Creator: Shurberg, Gitta
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: annuals, fertilizer, growth, landscape, nitrogen, ornamentals, perrenials, spad
Environmental Horticulture -- Dissertations, Academic -- UF
Genre: Horticultural Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The basis for current nitrogen (N) fertilizer recommendations for ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs, which may have different fertilization requirements than perennials, annuals, vines and groundcovers. Therefore, the current fertilizer recommendations need to be validated for these additional plant types. Knowledge of specific fertilizer requirements will allow for zoning of plants within the landscape based on their N fertilizer requirements, which should result in more efficient fertilizer application, thereby reducing the potential for nutrient losses (e.g., runoff, leaching, and volatilization) to the environment. Trials were conducted at The University of Florida -Institute of Food and Agricultural Sciences (UF-IFAS) Gulf Coast Research and Education Center (GCREC) in Wimauma, FL. Plots were 10 feet by 40 feet raised beds filled with soil from a subsurface horizon that is commonly used in central Florida for construction areas as fill . Drip irrigation was applied as needed. No mulch was added to beds in order to minimize outside N contributions. Nitrogen fertilizer requirements were determined for the following warm season bedding plant species: Golden Globe melampodium (Melampodium divericatum), Cora White vinca (Catharanthus roseus), and Profusion Cherry zinnia (Zinnia elegans); cool season bedding plant species: Montego Yellow snapdragon (Antirrhinum majus), Telstar Crimson dianthus (Dianthus chinensis), and Delta Pure Violet pansy (Viola timeswittrockiana); dicot perennial species: New Gold lantana (Lantana timeshybrida), Mystic Spires Salvia salvia (Salvia longispicata timesfarinacea) and bush daisy (Gamolepis chrysanthemoides); and monocot perennial species: Evergreen giant liriope (Liriope muscari) and White Christmas caladium (Caladium bicolor). Annual and perennial plant species were selected based on anecdotal evidence of high, moderate, and low fertilization needs for evaluation across a range of N fertilization regimes. The plants were fertilized every six weeks at five different N rates using a slow-release fertilizer based on current recommendations for ornamental plants growing in the landscape in Florida: 0, 2, 4, 6, and 12 lb/1000 square ft per yr (0.0, 9.8, 19.6, 29.4, and 58.8 g/square m per yr). Plant growth, aesthetic quality ratings, chlorophyll measurements, and flower cover index (second year only) were determined for all plant species at six-week intervals. Nitrogen fertilizer requirements were determined for each species based on these plant measurements.Based on the results of our study, most of the plant species required N fertilizer at rates that were within the range of N rates recommended by the Florida-Friendly Landscaping Program. However, plant response (growth, quality, chlorophyll, etc.) was more specific between evaluated species than the existing N fertilizer recommendations. More research is necessary to determine if recommended N rates need to be modified for species that did not perform well within the N fertilizer rates used in our study. The effect of soil type on N requirements also needs to be evaluated in order to make appropriate fertilizer recommendations for annual and perennial species grown in the landscape. Further studies are required to determine the environmental effects of applying N at rates based on the N requirement determined in our study.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Gitta Shurberg.
Thesis: Thesis (M.S.)--University of Florida, 2010.
Local: Adviser: Denny, Geoffrey.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2011-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0042612:00001

Permanent Link: http://ufdc.ufl.edu/UFE0042612/00001

Material Information

Title: Validating Nitrogen Requirements for Florida Landscape Plants
Physical Description: 1 online resource (192 p.)
Language: english
Creator: Shurberg, Gitta
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2010

Subjects

Subjects / Keywords: annuals, fertilizer, growth, landscape, nitrogen, ornamentals, perrenials, spad
Environmental Horticulture -- Dissertations, Academic -- UF
Genre: Horticultural Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The basis for current nitrogen (N) fertilizer recommendations for ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs, which may have different fertilization requirements than perennials, annuals, vines and groundcovers. Therefore, the current fertilizer recommendations need to be validated for these additional plant types. Knowledge of specific fertilizer requirements will allow for zoning of plants within the landscape based on their N fertilizer requirements, which should result in more efficient fertilizer application, thereby reducing the potential for nutrient losses (e.g., runoff, leaching, and volatilization) to the environment. Trials were conducted at The University of Florida -Institute of Food and Agricultural Sciences (UF-IFAS) Gulf Coast Research and Education Center (GCREC) in Wimauma, FL. Plots were 10 feet by 40 feet raised beds filled with soil from a subsurface horizon that is commonly used in central Florida for construction areas as fill . Drip irrigation was applied as needed. No mulch was added to beds in order to minimize outside N contributions. Nitrogen fertilizer requirements were determined for the following warm season bedding plant species: Golden Globe melampodium (Melampodium divericatum), Cora White vinca (Catharanthus roseus), and Profusion Cherry zinnia (Zinnia elegans); cool season bedding plant species: Montego Yellow snapdragon (Antirrhinum majus), Telstar Crimson dianthus (Dianthus chinensis), and Delta Pure Violet pansy (Viola timeswittrockiana); dicot perennial species: New Gold lantana (Lantana timeshybrida), Mystic Spires Salvia salvia (Salvia longispicata timesfarinacea) and bush daisy (Gamolepis chrysanthemoides); and monocot perennial species: Evergreen giant liriope (Liriope muscari) and White Christmas caladium (Caladium bicolor). Annual and perennial plant species were selected based on anecdotal evidence of high, moderate, and low fertilization needs for evaluation across a range of N fertilization regimes. The plants were fertilized every six weeks at five different N rates using a slow-release fertilizer based on current recommendations for ornamental plants growing in the landscape in Florida: 0, 2, 4, 6, and 12 lb/1000 square ft per yr (0.0, 9.8, 19.6, 29.4, and 58.8 g/square m per yr). Plant growth, aesthetic quality ratings, chlorophyll measurements, and flower cover index (second year only) were determined for all plant species at six-week intervals. Nitrogen fertilizer requirements were determined for each species based on these plant measurements.Based on the results of our study, most of the plant species required N fertilizer at rates that were within the range of N rates recommended by the Florida-Friendly Landscaping Program. However, plant response (growth, quality, chlorophyll, etc.) was more specific between evaluated species than the existing N fertilizer recommendations. More research is necessary to determine if recommended N rates need to be modified for species that did not perform well within the N fertilizer rates used in our study. The effect of soil type on N requirements also needs to be evaluated in order to make appropriate fertilizer recommendations for annual and perennial species grown in the landscape. Further studies are required to determine the environmental effects of applying N at rates based on the N requirement determined in our study.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Gitta Shurberg.
Thesis: Thesis (M.S.)--University of Florida, 2010.
Local: Adviser: Denny, Geoffrey.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2011-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2010
System ID: UFE0042612:00001


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1 VALIDATING NITROGEN REQUIR E MENTS FOR FLORIDA LANDSCAPE PLANTS By GITTA SHURBERG A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2010

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2 2010 G itta S hurberg

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3 To Dad, Mom, Rebecca, and Jessica for your love, support and patience and to everyone in my life wh o has encouraged my curiosities, I would not be here without you

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4 ACKNOWLEDGM ENTS I thank my family first and with all my heart. I also deeply appreciate Amy Shober for believing in my work and ability to learn with unwavering firmness. I thank Geoff Denny for igniting my interest in plants and for standing beside me as I learned. I thank Tomas for his love and support his passion drove me forward and kept me from falling apart. Thanks to my work friends (Nancy, Steve, Joyce, Gail Louise and everyone else) who helped me figure things out and gave their support and shared their expe rtise. Thanks to Butch for help with analysis. Thanks to Knox Nursery for donating the majority of the plants used in this study. Thanks to local grocery stores for all the paper bags.

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5 TABLE OF CONTENTS page ACKNOWLEDGME NTS ................................ ................................ ................................ ............... 4 LIST OF TABLES ................................ ................................ ................................ ........................... 9 LIST OF FIGURES ................................ ................................ ................................ ....................... 12 ABSTRACT ................................ ................................ ................................ ................................ ... 17 CHAPTER 1 LITERATURE REVIEW AND INTRODUCTION ................................ .............................. 19 Role of Nitrogen in Plants Physiology ................................ ................................ .................. 19 Plant Available Forms of Nitrogen ................................ ................................ ......................... 20 Root Structure and Nitrogen Uptake ................................ ................................ ...................... 21 Plant Mechanisms for Nitrogen Uptake ................................ ................................ ................. 22 Nitrogen Fertilizers ................................ ................................ ................................ ................. 23 Response of Trees to Nitrogen Fertilizers ................................ ................................ .............. 27 Response of Annual Plants to Nitrogen Fertilizers ................................ ................................ 32 Response of Herbaceous Perennials to Nitrogen Fertilizers ................................ ................... 35 Resear ch Objectives ................................ ................................ ................................ ................ 38 2 DETERMINATION OF NITROGEN REQUIREMENTS FOR THREE SPECIES OF WARM SEASON ANNUALS ................................ ................................ ............................... 41 Introduction ................................ ................................ ................................ ............................. 41 Materials and Methods ................................ ................................ ................................ ........... 41 Plant Material ................................ ................................ ................................ .................. 41 Experimental Design ................................ ................................ ................................ ....... 43 Soil Sampling and Analysis ................................ ................................ ............................. 44 Plant Growth and Shoot Dry Mass ................................ ................................ .................. 44 Plant Q uality and Chlorophyll Content ................................ ................................ ........... 45 Flower Cover Index ................................ ................................ ................................ ......... 45 Foliar Nutrient Concentration Analysis ................................ ................................ ........... 46 Statistical Analysis ................................ ................................ ................................ .......... 46 Results and Discussion ................................ ................................ ................................ ........... 47 Zinnia elegans a ngustifolia ) ................................ .............. 47 Plant growth and shoot dry mass ................................ ................................ .............. 47 Plant quality and chlorophyll content ................................ ................................ ....... 47 Flower cover index ................................ ................................ ................................ ... 48 Foliar nutrient concentration analysis ................................ ................................ ...... 49 Overall nitrogen requirement for zin nia ................................ ................................ ... 49 Catharanthus roseus ) ................................ ................................ .... 50

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6 Plant growth and shoot dry mass ................................ ................................ .............. 50 Plant quality and chlorophyll content ................................ ................................ ....... 50 Flower cover index ................................ ................................ ................................ ... 51 Foliar nutrient concentration analysis ................................ ................................ ...... 52 Overall nitrogen requirement for vinca ................................ ................................ .... 52 ( Melampodium divaricatum ) ................................ ........ 52 Plant growth and shoot dry mass ................................ ................................ .............. 52 Plant quality and chlorophyll content ................................ ................................ ....... 53 Flower cover index ................................ ................................ ................................ ... 55 Overall nitrogen requirement for melampodium ................................ ...................... 55 3 DETERMINATION OF NITROGEN REQUIREMENTS FOR THREE SPECIES OF COOL SEASON AN NUALS ................................ ................................ ................................ 79 Introduction ................................ ................................ ................................ ............................. 79 Materials and Methods ................................ ................................ ................................ ........... 79 Plant Material ................................ ................................ ................................ .................. 79 Experimental Design ................................ ................................ ................................ ....... 80 Soil Sampling and Analysis ................................ ................................ ............................. 82 Plant G rowth and Shoot Dry Mass ................................ ................................ .................. 82 Plant Quality and Chlorophyll Content ................................ ................................ ........... 83 Flower Cover Index ................................ ................................ ................................ ......... 83 Foliar Nutrient Concentration Analysis ................................ ................................ ........... 83 Statistical Analysis ................................ ................................ ................................ .......... 84 Results and Discussion ................................ ................................ ................................ ........... 85 Dianthus chinensis ) ................................ ........................... 85 Plant growth and shoot dry mass ................................ ................................ .............. 85 Plant quality and chlorophyll content ................................ ................................ ....... 85 Flower cover index ................................ ................................ ................................ ... 87 Foliar nutrient concentration analysis ................................ ................................ ...... 87 Overall nitrogen requirement for dianthus ................................ ............................... 88 Antirrhinum majus ) ................................ ..................... 89 Plant growth and shoot dry mass ................................ ................................ .............. 89 Plant quality and chlorophyll content ................................ ................................ ....... 90 Flower cover index ................................ ................................ ................................ ... 91 Foliar nutrient concentration analysis ................................ ................................ ...... 91 Overall nitrogen requirement of snapdragon ................................ ............................ 92 Viola wittrockiana ) ................................ ............................ 93 Plant growth and shoot dry mass ................................ ................................ .............. 93 Plant quality and chloroph yll content ................................ ................................ ....... 93 Flower cover index ................................ ................................ ................................ ... 94 Foliar nutrient concentration analysis ................................ ................................ ...... 94 Overall nitrogen requirement of pansy ................................ ................................ ..... 95

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7 4 DETERMINATION OF NITROGEN REQUIREMENTS FOR FIVE SPECIES OF HERBACEOUS PERENNIALS ................................ ................................ .......................... 131 Introduction ................................ ................................ ................................ ........................... 131 Materials and Methods ................................ ................................ ................................ ......... 131 Plant Material ................................ ................................ ................................ ................ 131 Experimental Design ................................ ................................ ................................ ..... 132 Soil Sampling and Analysis ................................ ................................ ........................... 134 Plant Growth and Shoot Dry Mass ................................ ................................ ................ 134 Plant Quality and Chlorophyll Content ................................ ................................ ......... 134 Flower Cover Index ................................ ................................ ................................ ....... 135 Foliar Nutrient Concen tration Analysis ................................ ................................ ......... 135 Statistical Analysis ................................ ................................ ................................ ........ 136 Results and Discussion ................................ ................................ ................................ ......... 136 Lantana ( Lantana hybrida ................................ ................................ ..... 136 Plant growth and shoot dry mass ................................ ................................ ............ 136 Plant quality and chlorophyll content ................................ ................................ ..... 137 Flower cover index ................................ ................................ ................................ 138 Tissue nutrient concentration ................................ ................................ ................. 138 Overal l nitrogen requirement for lantana ................................ ............................... 138 Bush Daisy ( Gamolepis chrysanthemoides ) ................................ ................................ .. 138 Plant growth and shoot dry mass ................................ ................................ ............ 138 Plant quality and chlorophyll content ................................ ................................ ..... 139 Flower cover index ................................ ................................ ................................ 140 Tissue n utrient concentration ................................ ................................ ................. 141 Overall nitrogen requirement for bush daisy ................................ .......................... 141 Salvia ( Salvia longispicata farinacea ) ................................ .............. 141 Plant growth and shoot dry mass ................................ ................................ ............ 141 Plant quality and chlorophyll content ................................ ................................ ..... 142 Flower cover index ................................ ................................ ................................ 142 Tissue nutrient concentration ................................ ................................ ................. 143 Overall nitrogen requirement of salvia ................................ ................................ ... 143 Liriope ( Liriope muscari ................................ ................................ 144 Plant growth and shoot dry mass ................................ ................................ ............ 144 Plant quality and chlorophyll content ................................ ................................ ..... 144 Tissue nutrient concentration ................................ ................................ ................. 145 Overall nitrogen requirement for liriope ................................ ................................ 145 Caladium ( Caladium bicolor ................................ ......................... 146 Plant growth and shoot dry mass ................................ ................................ ............ 146 Plant quality and chlorophyll content ................................ ................................ ..... 146 Tissue nutrient concentration ................................ ................................ ................. 147 Overall nitrogen requirem ent for caladium ................................ ............................ 148 5 CONCLUSIONS ................................ ................................ ................................ .................. 178 APPENDIX: RESULTS OF PERIODIC SOIL ANALYSIS ................................ ...................... 181

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8 LIST OF REFERENCES ................................ ................................ ................................ ............. 186 BIOGRAPHICAL SKETCH ................................ ................................ ................................ ....... 192

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9 LIST OF TABLES Table page 2 1 Soil pH, Adams Evans pH, lime requirements and amount of lime applied for St. Johns fill soil used in raised beds for the evaluation of N fertilizer requirement of landscape grown ornamental plants. ................................ ................................ .................. 72 2 2 Total irrigation and rainfall volumes applied to warm season annual plant species grown in raised beds in USDA hardiness zone 9b between June 2008 and October 2008. ................................ ................................ ................................ ................................ ... 73 2 3 Total irrigation and rainfall volumes applied to warm season annual plant species grown in raised beds in USDA hardiness zone 9b between April 2009 and August 2009. ................................ ................................ ................................ ................................ ... 74 2 4 Median visua l quality ratings for Zinnia elegans 'Profusion Cherry', Catharanthus roseus 'Cora White' and Melampodium divaricatum 'Golden Globe' grown in raised landscape beds and fertilized at five N rates for 18 weeks (2008 and 2009) in USDA hardiness zone 9b. ................................ ................................ ................................ .............. 75 2 5 Mean flower cover indices for Zinnia elegans 'Profusion Cherry', Catharanthus roseus 'Cora White' and Melampodium divaricatum 'Golden Globe' grown in raised landscape beds and fertilized at five N rates for 18 weeks (2009) in USDA hardiness zone 9b. ................................ ................................ ................................ .............................. 76 2 6 Leaf tissue nutrient concentrations from tissue collected at 18 weeks after planting (2009) from Zinnia elegans in USDA hardiness zone 9b compared with published values. ................................ ......... 77 2 7 Leaf tissue nutrient concentrations from tissue collected at 18 weeks after planting (2009) from Catharanthus roseus in USDA hardiness zone 9b compared with published values. ................................ ......... 78 3 1 Pesticides applied to cool season annual spe cies grown in raised beds in USDA hardiness zone 9b between 2009 2010. ................................ ................................ ........... 120 3 2 Total irrigation and rainfall volumes applied to cool season annual plant species grown in raised beds in USDA ha rdiness zone 9b between November 2008 and March 2009. ................................ ................................ ................................ ..................... 121 3 3 Total irrigation and rainfall volumes applied to cool season annual plant species grown in raised beds in USDA hardiness zone 9b b etween November 2009 and March 2010. ................................ ................................ ................................ ..................... 122

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10 3 4 Median visual quality ratings for Dianthus chinensis 'Telstar crimson', Viola x wittrockiana 'Delta pure violet' and Antirrhinum majus 'Montego yel low' fertilized at five N rates grown in two seasons (2008 and 2009) in U.S. Department of Agriculture hardiness zone 9b. ................................ ................................ ........................ 123 3 5 Flower cover index for Dianthus chinensis 'Telstar Crimson', V iola wittrockiana 'Delta Pure Violet' and Antirrhinum majus 'Montego Yellow' fertilized at five N rates (0, 2, 4, 6, and 12 lb N/1000 ft 2 per yr) grown in two seasons (2008 and 2009) in U.S. Department of Agriculture hardiness zone 9b. ................................ ........................ 124 3 6 Leaf tissue nutrient analysis for Dianthus chinensis raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 compared with published values. ................................ ................................ ..................... 125 3 7 Leaf tissue nutrient analysis for Dianthus chinensis raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2009 2010 compared with published values. ................................ ................................ ..................... 126 3 8 Leaf tissue nutrient analysis for Antirrhinum majus grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 compared with published values. ................................ ................................ ..................... 127 3 9 Leaf tissue nutrient analysis for Antirrhinum majus grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2009 2010 compared with p ublished values. ................................ ................................ ..................... 128 3 10 Leaf tissue nutrient analysis for Viola wittrockiana raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 c ompared with published values. ................................ ................................ ..................... 129 3 11 Leaf tissue nutrient analysis for Viola wittrockiana raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2009 2010 compared with published values. ................................ ................................ ..................... 130 4 1 Total irrigation and rainfall volumes applied to perennial plant species grown in raised beds in USDA hardiness zone 9b between July 2008 a nd June 2009. .................. 162 4 2 Total irrigation and rainfall volumes applied to perennial plant species grown in raised beds in USDA hardiness zone 9b between July 2009 and June 2010. .................. 163 4 3 Mean growth index for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 0 48 weeks after planting in USDA hardiness zone 9b. ................................ ................................ ................................ ............................ 164 4 4 Mean growth index for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 54 96 weeks after planting in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 165

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11 4 5 Median visual quality ratings for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 0 to 48 weeks after planting in USDA hardiness zone 9b. ................................ ................................ ................................ 166 4 6 Median visual quality ratings for selected perennial plant species grown in raised landscape beds and fertilized at five N rates for 54 96 weeks (2008 2009) in USDA hardiness zone 9b ................................ ................................ ................................ ............. 168 4 7 Mean SPAD measurements for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from0 to 48 weeks after planting in USDA hardiness zone 9b. ................................ ................................ ................................ 170 4 8 Mean SPAD measurements for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 54 to 96 weeks after planting in USDA hardiness zone 9b. ................................ ................................ ................................ 171 4 9 Mean flower cover indices for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 0 to 48 weeks after planting in USDA hardiness zone 9b ................................ ................................ ................................ 172 4 10 Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from lantana ( Lantana hybrida USDA hardiness zone 9b. ................................ ................................ ................................ 173 4 11 Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from bush daisy ( Gamolepis chrysanthemoides ) plants (n = 45) grown in raised beds in USDA hardiness zone 9b. ................................ ................................ ............................ 174 4 12 Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from salvia ( Salvia longispicata farinacea in raised beds in USDA hardiness zone 9b. ................................ ................................ ..... 175 4 13 Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from liriope ( d beds in USDA hardiness zone 9b. ................................ ................................ .................... 176 4 14 Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from Caladium bicolor raised beds in USDA hardiness zone 9b. ................................ ................................ ................................ 177 A 1 Mean soil nutrient content (Mehlich 1) of raised flower beds fertilized at five N rates in 2008 2010 for 6 48 weeks after planting (WAP) fertili zed at five N rates in 2008 2010. ................................ ................................ ................................ ................................ 182 A 2 Mean soil nutrient content (Mehlich 1) of raised flower beds fertilized at five N rates in 2008 2010 for 54 90 weeks after planting fertilized at five N rates in 2008 2010. .... 184

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12 LIST OF FIGURES Figure page 2 1 Growth measurements of zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ .................. 56 2 2 Growth measurements of zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ .................. 57 2 3 Shoot dry mass of Zinnia ( Zinnia elegans angustifolia in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ .. 58 2 4 SPAD measurements of Zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 week s after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ .................. 59 2 5 SPAD measurements of Zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ .................. 60 2 6 Tissue concentrations of total Kjeldahl N (TKN) collected at 18 weeks (2009) after planting for zinnia ( Zinnia elegans angustifolia plants grown in raised landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. ................................ ................................ ................................ ................................ ....... 61 2 7 Growth indices of vinca ( Catharanthus roseus landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 62 2 8 Growth indices of vinca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 63 2 9 Shoot dry mass (g) of vinca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA ha rdiness zone 9b. ................................ ................................ ................................ .............. 64 2 10 SPAD measurements of vinca ( Catharanthus roseus landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 65

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13 2 11 SPAD measurements of vinca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 66 2 12 Tissue concentrations of total Kjeldahl N (TKN) of vinca ( Catha ranthus roseus rates for 18 weeks in USDA hardiness zone 9b. ................................ ................................ 67 2 13 Growth indices of melampodium ( Melampodiu m grown in raised landscape beds (2008) and fertilized with at five N rates for 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. ................................ ................................ ................................ ................................ .. 68 2 14 Growth indices of melampodium ( Melampodium grown in raised landscape beds (2009) and fertilized with at five N rates for 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. ................................ ................................ ................................ ................................ .. 69 2 15 SPAD measurements of melampodium ( Melampodium grown in raised landscape beds (2008) and fertilized with at five N rates for 12 weeks in USDA hardiness zone 9b at a) 6 we eks after planting (WAP) and b) 12 WAP. ................................ ................................ ................................ ................................ .. 70 2 16 SPAD measurements of melampodium ( Melampodium grown in raised landscape beds (2009) and fertilized with at five N ra tes for 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. ................................ ................................ ................................ ................................ .. 71 3 1 Growth indices of dianthus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 96 3 2 Growth indices of dianthus ( Dianthus ) grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ....... 97 3 3 Dry shoot mass of dianthus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates at 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ .............. 98 3 4 Dry shoot mass of dianthus ( ) grown in raised landscape beds (2009) and fertilized with at five N rates at 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ .............. 99 3 5 SPAD measurements of dianthus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 100

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14 3 6 SPAD measurements of dianthus ( ) grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 101 3 7 Tissue concentrations of total Kjeldahl N (TKN) for dianthus ( Dianthus chinensis ) grown in raised landscape beds (2008) and fertilized with at five N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 102 3 8 Tissue concentrations of total Kjeldahl N (TKN) for dianthus ( Dianthus chinensis ) grown in raised landscape beds (2009) and fertilized with at five N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 1 03 3 9 Growth indices of snapdragon ( Antirrhinum maju s raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 104 3 10 Growth indices of snapdragon ( Antirrhinum majus raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 105 3 11 Shoot dry mass of snapdragon ( Antirrhinum majus raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ 106 3 12 Shoot dry mass of snapdragon ( Antirrhinum majus raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ 107 3 13 SPAD measurements of snapdragon ( Antirrhinum majus in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 week s after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 108 3 14 SPAD measurements of snapdragon ( Antirrhinum majus in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 109 3 15 Tissue concentrations of total Kjeldahl N (TKN) of snapdragon ( Antirrhinum majus N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 110 3 16 Tissue concentrations of total Kjel dahl N (TKN) of snapdragon ( Antirrhinum majus N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 111

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15 3 17 Growth indices of pansy ( Viola wittrockiana landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ..... 112 3 18 Growth indices of pansy ( Viola wittrockiana landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks af ter planting (WAP), b) 12 WAP and c) 18 WAP. ..... 113 3 19 Shoot dry mass of pansy ( Viola wittrockiana landscape beds (2008) and fertilized with at five N rate s for 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 114 3 20 Shoot dry mass of pansy ( Viola wittrockiana landscape beds (2009) and fertilized with at five N rates f or 18 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 115 3 21 SPAD measurements of pansy ( Viola wittrockiana raised landscape beds (2008) and fertilized with at five N rates f or 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 116 3 22 SPAD measurements of pansy ( Viola wittrockiana raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. ................................ ................................ ................................ ................................ 117 3 23 Tissue concentrations of total Kjeldahl N (TKN) for pansy ( Viola wittrockiana N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 118 3 24 Tissue concentrations of total Kjeldahl N (TKN) for pansy ( Viola wittrockiana N rates collected at 18 weeks in USDA hardiness zone 9b. ................................ ............ 119 4 1 Shoot dry mass (g) of lantana ( Lantana hybrida grown in raised landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............................ 149 4 2 SPAD measurements of lantana ( Lantana hybrida landscape beds (2008 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 150 4 3 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from lantana ( Lantana hybrida plants grown in raised landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. ................................ ...... 151

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16 4 4 Shoot dry mass (g) of bush daisy ( Gamolepis chrysanthemoides ) grown in raised landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............................ 152 4 5 SPAD measurements of lantana Bush daisy ( Gamolepis chrysanthemoides ) grown in raised landscape beds (2008 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ 153 4 6 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from bush daisy ( Gamolepis chrysanthemoides ) plants grown in raised landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. .............................. 154 4 7 Shoot dry mass (g) of salvia ( Salvia longispicata farinacea in raised landscape beds and fertilized with at five N rate s for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 155 4 8 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from salvia ( Salvia longispicata farinacea landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. ............. 156 4 9 Growth indices of Liriope ( l andscape beds (2008 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 157 4 10 Shoot dry mass (g) of liriope ( landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............................ 158 4 11 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from l iriope ( beds and fertilized with at five N rates in USDA hardiness zone 9b. .............................. 159 4 12 SPAD measurements of caladium ( Caladium landscape beds (2008 2010) and fertilized with at five N rates for 78 weeks in USDA hardiness zone 9b. ................................ ................................ ................................ ............ 160 4 13 Tissue concentrations of total Kjeldahl N (T KN) collected at 78 weeks after planting from caladium ( Caladium and fertilized with at five N rates in USDA hardiness zone 9b. ................................ ...... 161

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17 Abstract of Thesis Presented to t he Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science VALIDATING NITROGEN REQUIREMENTS FOR FLORIDA LANDSCAPE PLANTS By Gitta Shurberg December 2010 Chair: Geoffrey C. Denny Major: Horticultural Science The basis for current nitrogen (N) fertilizer recommendations for ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs which may have different fertilization req uirements than perennials, annuals, vines and groundcovers. Therefore, the current fertilizer recommendations need to be validated for these additional plant types Knowledge of specific fertilizer requirements will allow for zoning of plants within the la ndscape based on their N fertilizer requirements which should result in more efficient fertilizer application, th ereby reducing the potential for nutrient losses (e.g., runoff, leaching, and volatilization) to the environment. Trials were conducted at Th e University of Florida Institute of Food and Agricultural Sciences (UF IFAS) Gulf Coast Research and Education Center (GCREC) in Wimauma FL. Plots were 10 feet by 40 feet raised beds filled with soil from a subsurface horizon that is commonly used in ce needed. No mulch was added to beds in order to minimize outside N contributions. Nitrogen fertilizer requirements were determined for the following warm season bedding plant spe cie s: Melampodium divericatum ) v inca ( Catharanthus roseus ) and z innia ( Zinnia elegans ) ; c ool season bedding plant s pecies :

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18 s napdragon ( Antirrhinum majus ) d ian thus ( Dianthus chinensis ) and p ansy ( Viola wittrockiana ) ; dicot p erennial s pecies : l antana ( Lantana hybrida ) s alvia ( Salvia longispicata farinacea ) and b ush d aisy ( Gamolepis chrysanthemoides ) ; and monocot perennial species : Evergreen l iriope ( Liriope muscari ) and c aladium ( Caladium bicolor ) Annual and p erennial p lant s pecies were selected based on anecdotal evidence of high, moderate, and low fertilization needs for evalu ation across a range of N fertilization regimes. The plants were fertilized every six weeks at five different N rates using a slow release fertilizer based on current recommendations for ornamental plants growing in the landscape in Florida : 0 2, 4, 6, an d 12 lb/1000 ft 2 per yr ( 0.0 9.8, 19.6, 29.4, and 58.8 2 per yr ) P lant growth, aesthetic quality ratings, chlorophyll measurements, and flower cover index ( second year only) were determined for all plant species at six week intervals. N itrogen fer tilizer requirements were determined for each species based on these plant measurements. Based on the results of our study, m ost of the plant species required N fertilizer at rates that were within the range of N rates recommended by the Florida Friendly La However, plant response (growth, quality, chlorophyll, etc.) was more specific between evaluated sp ecies than the existing N fertilizer recommendations. M ore research is necessary to determine if recommended N rate s need to be modified for species that did not perform well within the N fertilizer rates used in our study The effect of soil type on N requirements also needs to be evaluated in order to make appropriate fertilizer recommendations for annual and perennial species grown in th e landscape Further studies are required to determine the environmental effects of applying N at rates based on the N requir ement determined in our study.

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19 CHAPTER 1 LITERATURE REVIEW AND INTRODUCTION Role of Nitrogen in Plants Physiology Nitrogen (N) has an essential role in plant growth and development In general, the N content of plants ranges from 1 6% of the dry mass of leaf tissue (Cockx and Simonne, 2003) Only carbon, oxygen and hydrogen are more plentiful in plants (Raven et al., 2005) Nitrogen is a n integral component of all living cells, proteins, enzymes, nucleic acids and plays an important role in plant metabolic processes (Mills and Jones, 1996) Proteins are macromolecules composed of amino acids ; they have a varie ty of function s with in plants (Raven et al., 2005) Proteins can serve as structural material, as well as transporters of essential substances (Taiz and Zeiger, 2006) In addition, enzymes are proteins that catalyze chemical reactions (Taiz and Zeiger, 2006) Nitrogen is a component of chlorophyll, which is the compound responsible for photosynthesis (Brady and Weil, 2002; Raven et al., 2005) Nitrogen is also a part of energy transfer compounds, such as adenosine triphosph ate (ATP) ; ATP allows cells to store and use the energy released in metabolism (Taiz and Zeiger, 2006) N itrogen is a significant component of DNA (a nucleic acid) and contains the genetic material that allows cells to reproduce (Raven et al., 2005) Due to the fact that N plays such an important role in plant growth and development, it is required in relatively large amounts by living plants, making it a macronutrient for plants (Brady and Weil, 2002) Some chemical forms of N are mobile in plants allowing N to move to areas of active grow th, where supplies of N are most needed (Wallace, 1943) For this reason, symptoms of N deficiency are first detectable on old leave s (Wallace, 1943) In order to understand the importance of N to plant growth and developm ent, it is important to understand how nitrogen is taken up by translocated throughout and used by plants.

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20 Plant Available Forms of Nitrogen Plants are able to take up N in two forms: nitrate (NO 3 ) and ammonium (NH 4 + ) (Mills and Jones, 1996) Nitrogen in the soil is converted into ammonium (NH 4 + ) by soil micro organisms by means of mineralization at which point it may then be oxidized to form nitrate NO 3 through nitrification (Miller and Cramer, 2004) Nitrate is able to move in soil solution due to its negative charge (Brady and Weil, 2002) This mobility allows it to be easily taken up by the roots and also easily leached out of the root zone (Scholberg et al., 2009) Nitrogen is more easily leached in sandy soils that have a low water holding capacity such as the soils common to Florida (Scholberg et al., 2009) Nitrogen also enters the root in the form of NH 4 + (Miller and Cramer, 2004) Assimilation of NH 4 + requires less energy than NO 3 because it can be assimil ated directly 2 and then NH 4 + via nitrate reductase and nitrite reductase ; a process that requires additional energy from the plant (Cardenas Navarro et al., 200 6; Jampeetong and Brix, 2009) Thus, many plants prefer NH 4 + to NO 3 (Cardenas Navarro et al., 2006; Jampeetong and Brix, 2009) However, optimal plant growth is realized when N is supplied in both forms, NH 4 + and NO 3 rather than either form alone (von Wiren et al., 2000) If only NH 4 + is supplied, it can become toxic to plants (Jampeetong and Brix, 2009) There are several hypotheses about why NH 4 + is toxic to plants but none have been proven One reason NH 4 + may become toxic is due to medium acidification because NH 4 + releases H + when it is incorporated into a protein (Britto et al., 2001) The optimal ratio of NO 3 to NH 4 + varies among species, but is related to plant age and the pH of the substrate (Miller and Cramer, 2004) In waterlogged and acidic soils, NH 4 + is predominant and the plants growing in these conditions have a higher tolerance to high NH 4 + concentrations (Jampeetong and Brix, 2009) Ammonium is prevalent in wetland soils because low oxy gen availability limits the rate of nitrification (Jampeetong and Brix, 2009)

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21 Crdenas Navarro et al. (2006) determine d the effects of NO 3 and NH 4 + ratios in nutrient solutions on the growth and pro duction of runners, fruits and daughter plants of strawberry ( Fragaria x ananassa Duch.) grown in a hydroponic system. The NH 4 + :NO 3 treatment ratios were: 0:4, 1:3, 2:2, 3:1, and 4:0, at a constant nitrogen (N) concentration of 4 mol m 3 Th e authors repo rted that growth of the mother plant was unaffected by treatments ; however, fruit number increased with when the ratio of NH 4 + to NO 3 in the hydroponic solution increased The number of daughter plants produced was not significantly affected by ratio of N H 4 + :NO 3 in solution. However, the dry mass per plant, total dry mass and the number of second generation plants per first generation plants were reduced when the NH 4 + proportion was above 50%. The study concluded that increasing NH 4 + concentrations in sol utions stimulated fruit production, which led to a higher assimilate demand, a decrease of carbohydrate reserves, and a reduction in the development of daughter plants (Cardenas Navarro et al., 2006) Salvinia natans (L.) All. was found to have a high growth rate, a high nutrient uptake rate and was determined to be tolerant of high NH 4 + levels, making it a good candidate for use in treatment of wastewaters (Jampeetong and Brix, 2009) Underst anding the differences in plant tolerances to varying forms of inorganic N is essential to production and utilization of plants. Root Structure and Nitrogen Uptake Root structure which varies by species, is important to ensure adequate uptake of N by plan ts When a plant is N deficient, a higher proportion of photosynthates are translocated to the roots, thereby increas ing root size (as measured by total mass, length or area) relative to the shoot (Miller and Cramer, 2004) Another manner by which plants work to optimiz e N uptake is by increasing root mass in areas of high N concentration (Wang et al., 2006) Finer roots take up more nutrients per unit root mass than thicker roots because fine r roots have a higher surface area (Wang et al., 2006) Root hairs are tubular outgrowths of root epidermal cells which greatly

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22 increase nutrient absorption (Raven et al., 2005) Root hairs are able to increase absorption of immobile nutrients by growing into soil particles and small pores (Wang et al., 2006) However, N in t he soil solution around the immobile roots depletes over time (Gorska et al., 2008a) Plant Mechanisms for Nitrogen Uptake Nitrogen is drawn to the root surface and enters the root by mass flow and diffusion (Miller and Cramer, 2004; Wang et al., 2006) Mass flow is driven by a pressure gradient w ithin the plant that is created by transpiration (Miller and Cramer, 2004) while d iffusion is movement of ions along the concentratio n gradient (Wang et al., 2006) Diffusion occurs rapidly over short distances but very slow ly over long distances (Raven et al., 2005) The transport of N across the plasma mem brane (cell membrane) is sensitive to temperature, oxygen concentration, light availability, carbon dioxide availability and metabolic inhibitors (Wang et al., 2006) There are two high affinity transport systems (HAT s ) and one low affinity transport system (LATS) that are involved with NO 3 uptake operating at different external NO 3 concentrations (Miller and Cramer, 2004) The HATS take up NO 3 at low external concentrations while the LA TS takes up NO 3 at high concentrations (Miller and Cramer, 2004) The proton gradient across the plasma membrane is the source of energy for HATS (Miller and Cramer, 2004) Pumps, channels and carriers are the three transport protein types that move nutrients across the plasma memb rane (Taiz and Zeiger, 2006) Pumps symport and antiport carriers are active transport proteins and channels and the uniport carr iers are passive transport proteins X ylem is the principal pathway for the transportation of nutrients from the roots to the shoots; however, there is collaboration between the xylem and the phloem in order to supply nutrients throughout the plant (Wang et al., 2006) This collaboration, among other thing s ensures that the formation of the roots is proportional to the shoot growth (Wang et al., 2006)

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23 While n utrient uptake is regulated by shoot demand, the method used to signal changes in the N status of the shoot to the root is unclear (Wang et al., 2006) When N availability is limited, N demand in the root is prioritized over N demand in the shoot (von Wiren et al., 2000) Ultimately, N concentrations within the plant are maintained by balancing N availability by regulating new growth with the sink demand (Scholberg et al., 2009) Nitrate and NH 4 + follow different transport systems for development and growth Nitrate must be reduced i n the roots or leaves before it can be assimilated into organic compounds within the plant (Wang et al., 2006) Nitrate that is not assimilated into organic compounds is stored in the vacuoles (Mills and Jones, 1996) In contrast, NH 4 + m ust be incorporated quickly into organic molecules because when it is free within the plant it alters the photosynthetic mechanism (Mills and Jones, 1996) Gorska et al. (2008b) showed that the response to a sudden change i n NO 3 availability initiate d hydraulic changes in the roots of Cucumis sativus L. and Solanum lycopersicum L. The authors concluded that the dramatic response observed was likely a reflection of changes in the membrane permeability. This membrane permeabi lity was determined to be the result of the presence and activity of aquaporins which are proteins in the cell membranes that regulate the flow of water (Gorska et al., 2008a) Nitrogen Fertilizers Increased crop production was made possible by the use of inorganic, industrially produced fertilizers (Matson et al., 1997) Nitrogen can be applied to the landscape in many chemical forms (e.g., nitrate a nd ammoni um) in the form synthetic fertilizer or organic materials such as compost, lawn waste, peat or sludge (Latimer et al., 1996) Nitrogen in f ertilizers can be in water soluble, slow release or controlled release forms (Shober, 2009)

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24 For N to be used by plants organic N must be mineralized to in organic forms (Latimer et al., 1996) The ammoniacal forms of N are susceptible to volatilization (Latimer et al., 1996) Plants can use the ammoniacal N or i t can be converted to nitrate forms by bacteria (Latimer et al., 1996) Nitrate forms are not retained by cation exchange and it is soluble and moves through solution with ease; therefore, nitrate can be easily leached (Latimer et al., 1996) In order to minimize N losses, N must be kept in the root zone through fertilizer management practices, including application timing and placement, and irrigation manageme nt (Latimer et al., 1996) Soil pH affects the availability of nutrients for pl ant uptake (Mills and Jones, 1996) with nutrient availabili ty optimized when soil pH is in the range of 5.5 7.0 (Brady and Weil, 2002) N itrat e and NH 4 + affect the pH in the rhizosphere in different ways (Brady and Weil, 2002) Nitrate is negatively charged and moves easily in soil water solution and exchanges with HCO 3 or OH ions, which creates an increase in pH of the soil solution in the rhizosphere (Brady and Weil, 2002) Ammonium is positively charged and exchanges at the surface of the root with hydrogen ions, which lowers the pH of the solution in t he rhizosphere (Brady and Weil, 2002) Therefore, high fertilizer rates using NH 4 + can influence pH in the soil solution. When N is applied to the soil in the form of NH 4 + the NH 4 + breaks down into nitrate; this process releases hydrogen atoms which go into soil water solution and effects nutrient availability (Smith; Vagts, 2005) Low soil electrical conductivity (EC) is associated with low substrate concentrations of N and K (Mills and Jones, 1996) Electrical Conductivity can increase as salts accumulate in the so il due to excessive fertilizer application particularly in a greenhouse setting. There are environmental considerations when applying N. Between 40 to 60% of N that is applied to plants in fertilizers is actually taken up by plant root; the remainder stays in the soil or

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25 moves offsite via leaching, runoff or volatilization (Matson et al., 1997) Therefore, it is clear that fertilizers should be applied efficien tly to prevent losses of N to the environment (Latimer et al., 1996) A good way of achieving efficient application is by matching fertilization with plant nutrient requirements (Matson et al., 1997) Research to determine how to limit nutrient losses from urban areas is becoming essential (Line et al., 2002) The average total N, P and sediment export for residential uses was found to be 256% greater than the exports from wooded sites (Line et al., 2002) Land management practices such as fertiliz er application rates timing of fertilizer application and method of applicatio n, need to be monitored more closely to ensure that fertilizer application does not exceed the specific N requirements of growing plants (Line et al., 2002) Often ferti lizer is applied improperly and it can come into contact with impervious surfaces like streets, driveways or sidewalks where it can be carried by water directly to surface water bodies via stormdrains (Line et al., 2002) Erickson et al. (2001) found that N leaching losses were approximately 10 times greater from mixed species landscapes than from St. Augustinegrass landscape. Results showed that 48.3 kg N ha 1 were leached from the mixed landscape and 4.1 kg N ha 1 were leached from St. Augstinegrass annually (Erickson et al., 2001) Saha and Trenholm (2007) also found that N leaching was greater in mixed landscapes when compared with turfgrass plots This difference may be due to the reduced vegetation density of the mixed landscape as well as the longer establishment periods (Erickson et al., 2001) There are potential environmental consequences of N fertilizers. A surplus of N in surface water systems can cause eutrophication (Vasas et al., 2007) Eutrophication is caused by nutrient over enrichment, which disrupts ecosystems by causing algal blooms that limit oxygen for fish and other aquatic life (Matson et al., 1997) It also prevents other vegetation from surviving due

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26 to the intense competitio n for light (Matson et al., 1997) This can lead to fish kills and ecosystem degradation (Matson et al., 1997) The impacts of eutrophication include lowered aesthetic appeal of water bodies, loss of fishing, or recreational areas (Lewitus an d Holland, 2003) There is also potential health risks evolved with N when it enters drinking water supplies. The drinking water standar 1 for nitrate (Erickson et al., 2001) When high levels of NO 3 are ingested it can change to NO 2 (Gunes et al., 1996) The NO 2 oxidizes iron in the hemoglobin of the red blood cells and forms methemoglobin (Oram, 2010) Methemoglobin does not have the ability to carry oxygen (Oram, 2010) The condition in which blood is not able to carry sufficient oxygen to the cells of the body and causes the skin to appear blue is known a (Gunes et al., 1996; Oram, 2010) Infants may be particularly susceptible to this condition because they lack an enzyme system to turn methemoglobin back to oxyhemoglobin. For this reason pregnant women and nursing mothers should not drink water with NO 3 over the standard set by the EPA (Oram, 2010) Nitrite in the bloo d may also cause nitrosamines to form, which are believed to be carcinogenic (Gunes et al., 1996) Accurate fertilizer recommendations are necessary in order to sustain good water quality textured with low fertility (low cation exchange capacity, [CEC]) (Broschat et al., 2008) As a result, supplemental nutrients are easily leached downward through the soil profile. In an optimum nutrient management system, the minimum amount of nutrient required for maximum growth should be applied. This reduces both cost and nutrient loss to the environment (Dubois et al., 2000)

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27 Response of Trees to N itrogen Fertilizer s Fertilization requirements for plants that are established in the landscape have r eceived little attention in part because woody dicots often perform well with little or no supplemental fertilizer (Broschat et al., 2008) There are also variation s in soil type and climactic conditions that could af fect fertilizer recommendations (Broschat et al., 2008) In addition, there is a multitude of ornamental plant species especially in Florida, that the task of determining proper N fertilization rates for all of them seems particularly daunting. Research on N fertilization requirements of annuals, perennials, vines or groundcovers in the landscape is limited. Most nutrient requirement and fertilizer requirement research for ornamentals that exists focuses on the ferti lization requirements of trees and shrubs but e ven this information is fairly limited (Shober et al., 2010) The limited body of research on the response of trees and shru bs to N fertilization provides the basis for current fertiliz er recommendations for all ornamental plants. Nitrogen rate recommendations for fieldscape and landscape ornamentals are between 48 1 (Rose, 1999) There are few guidelines for selecting a rate within the range for a particular species (Rose, 1999) N fertilizer recommendations are divided into low, medium, and high rates of 0 2, 2 4 and 4 6 l b/ 1000 ft 2 per yr, respectively (Florida Department of Environmental Protection, 2002; Flo rida Yards and Neighborhoods Program, 2006) Growth is emphasized in tree production because value is dictated by the height and spread of the tree (Cabrera, 2003) Also, the faster the plan ts grow the more plants can be produced in a limited space or with limited resources. Past research aimed to determine this maximum growth response.

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28 Gilman et al. (2000) determine d if N rate or fertilizer type influenced tree growth (M agnolia grandiflora L. ) in sandy soils and if transplanted trees respond to fertilizers during the first year after planting. The authors showed that trees receiving N grew faster th an control trees (trees receiving no additional N). Gilman et al. (2000) discussed that the N fertilizer effect (faster growth compared to controls) during the fir st year of the study could be due to the fact that the trees were grown in USDA Hardiness zone 9 which may have expedited the establishment rate in comparison to other studies. Gilman et al. (2000) also determined that N rates above 4.2 lb N/1000 ft 2 per yr did not result in increased tree height or trunk diameter during the first 2 years after planting. Trees receiving 8.3 lb N/1000 ft 2 per yr were significantly t aller after the third and forth years after planting (Gilman et al., 2000) In a study by Lloyd et al. (2006) researchers determine d the impacts of three N fertiliz er 1 ) and two irrigation schedules ( irrigated 25% or 50% container capacity ) in the nursery on growth and stress resistance of crabapple ( Malus a ngustifolia (Aiton) were transplanted into the landscape. The authors concluded that tree growth during the first year after planting into the landscape was positively correlated with N concentrations from when the plants w ere treated in the nursery. However, those same trees had reduced photosynthesis during the dry season, which suggested a reduced drought tolerance (Lloyd et al., 2006) Tre es receiving the lower rates of N had higher drought stress tolerance and lower insect count. The N fertilizer effects on growth did not continue into the following year of the study (Lloyd et al., 2006) Smith (1978) recommended an annual application of N at a rate of 3 lbs N /1000ft 2 per yr or a biannual application of N at a rate of 6 lbs /1000ft 2 every other year to maintain healthy trees. If the trees were in poor conditi on, then he recommended 6 lbs. N/1000 ft 2 /yr (Smith,

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29 1978) Parameters examined by Smith (1978) were foliage color, shoot and root growth, drought tolerance, trunk and stem health, and growth and quality Van de Werken and Warmbrod (van de Werken, 1969) deter mined that fertilizer had little effect on the growth rate of shade trees until after the third year after planting. After the fourth year, trees receiving N at a rate of 1lbN/120 ft 2 per yr had significantly greater growth ( e.g., height, spread and trunk diameter). Seven years after planting, 120 lbs N was applied to trees that had not received any N up to that point. Within the year of this final application there was a large response in growth rate to that application that was in contrast to the precedin rate (van de Werken, 1969) Many studies conflict on the issue of whether or not trees should be fertilized in the first years after planting. Some research and papers suggest that there may not be any benefits. Van de Werken (1981) looked at the effects of N, P and pH levels on the growth of Acer saccharum, Liriodendron tulipifera L., and Quercus palustris Mnchh in the landscape. Treatments included 1) pH 5.2, P low, N 0 lbs/acre per year 2) pH 5.2, P low, N 120 lbs/acre per year 3) pH 6.2, P high, N 60 lbs/acre per year and 4) pH 6.2, P low, N 120 lbs/acre per year Data collection included height, crown diameter and caliper. There were no differences among treatments for growth after three years in any of the species. There were slight differences after four years Trees receiving the higher N rates were significantly larger after eight years for all species for average trunk caliper, height and crown diameter Differences between treatments after eleven ye ars were more obvious (van de Werken, 1981) A study by Schulte and Whitcomb (1975) focused on the effects of fertilizer levels and soil amendments on the establishment of tree s ( Acer saccharinum L. ). The experiment tested nine soil amendments and three N fertilizer rates (0 20, and 40 lb1000 ft 2 per mo nth) Trees grown in

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30 a clay loam soil increased in size with the increase of N. The authors concluded that trees should be fer tilized during the first growing season after planting into the landscape. They also determined that soil amendments should not be used to aid in tree establishment (Schulte and Whitcomb, 1975) Recent studies on tree nutrient requirements have focused on the effects of nursery practices on landscape performance and on the timing of fertilizer application to correspond to plant demand in order to increase nutrient use efficiency A study perfor med by Cabrera and Devereaux (1999) determine d the relationship between N fertility management during nursery production and plant growth and performance of crape myr tle ( Lagerstroemia indica L. Lagerstroemia fauriei after transplant i nto the landscape. N itrogen was applied at six concentrations ( 15 30 60 120 210 and 1 ) during the nursery production At 16 weeks after treatment the authors found that there were significant differences in plant biomass where biomass increased with increasing N rate 1 Above this rate, biomass began to decrease Plant survival following transplant was not affected by the fertilizer treatment s Plant root to shoot ratios which had been significantly affected by N rate, equalized over time after transplant (no difference following 16 weeks after treatment ). The c onclusions of this study were that N status at the end of the production phase could significantly influence plant performance ( e.g., growth rates, plant size, and flower development) for months after the trees were transplanted into the landscap e (Cabrera and Devereaux, 1999) Ferrini and Baietto (2006) examined the response o f trees to fertilization (N P K) in an urban environment and determined that fertilization does not improve plant establishment, growth and physiology after transplanting. The authors suggested that reason for no response could be due to the different cond itions under which the experiments were conducted (Ferrini

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31 and Baietto, 2006) One experiment took place in a new parking lot in the S W part of Milan, Italy and the other experiment took place in a downtown street. The authors also suggest that due to the limited research on urban plants, fertilizer recommendations adapted from non urban areas may not be appropriate for use in the urban environment (Ferrini and Baietto, 2006) Neely (1980) published results of a four year project on fertilizing established trees. In this study three complete fertilizers (20 N 4 P 8 K 30 3 10, 34 3 7, and 3 3.5 0 0) were applied at the N rates of 2, 4, and 6 lb N/1000 ft 2 per yr to four tree species ( Quercus palustris, Lirodendron tulipifera L., Acer platanoides L and Gleditsia triacanthos L. f. inermis ). The author found that fertilizer formulation did not have an effect and that fertilized trees grew more than unfertilized trees with the 6 lb N/1000 f t 2 per yr resulted in significantly more growth than the 2 or 4 lb rates (Neely, 1980) Gilman and Yeager (1990) evaluated the response of laural oak ( Quercus hemisphaerica Michx ) and japanese ligustrum ( Ligustrum japonicum Thunb.) to a pplications of controlled release fertilizer and a soluble gra nular fertilizer applied at two N rates (3 and 6 lb N/1000 ft 2 /yr) The authors found that the type of fertilizer did not affect tree height or caliper diameter of either species. Laurel o ak receiving the N at 6 lb/1000 ft 2 per year rate grew taller than t rees fertilized at the 3 lb /1000 ft 2 N rate but there was no effect of N rate on caliper diameter T he t ype of fertilizer did not affect growth of ligustrum ; however, the plants receiving soluble granular fertilizer were larger than the control (no ferti lizer) plants. Because there was no effect of fertilizer type on tree growth Gilman and Yeager (1990) suggest ed that slow r elease N is preferred because it can reduc e N leaching and reduce labor during application. Rose and Biernacka (1999) found that N fertilization rate influenced tissue nutrient contents, dry weight, and shoot/root ratio of f reeman maple ( Acer freemanii E. Murr.

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32 Tissue N, P, and K accumulation during the growin g season were correlated with dry mass accumulation and increased with time. The Secretariat Tree Care Association Inc. (2008) published standard tree care practices which include recommendations for fertilization. They recommend using a slow release fertilizer at N rates between 2 4 lb /1000 ft 2 /yr not to exceed 6 lb /1000 ft 2 per yr. Quick release fertilizers should be applied at N rates between 1 2 lbs/1000 ft 2 per application not to exceed 4 lb N/1000ft 2 per yr (Secretariat Tree Care Industry Association, 2008) Response of Annual Plants to N itrogen Fertilizer s Annual plants die or are no longer useful in a landscape setting after one growing season. They are produ ced from seed and usually have flowers. Annual plants are often used in flowerbeds, borders and containers (Bl ack, 2006; Black and Tjia, 2000) for immediate color in a landscape. Therefore, the faster the plant fills a space, or grows, the more the consumer can enjoy the color. Research on the fertilization requirements of landscape annuals has primarily focused on specific nutritional requirements and fertilization needs of the crop during production in greenhouses and nurseries. Consequently, t here has been little research to determine annual plant fertilizer requirements in the landscape. Van Iersel et al. (1998a) studied the effects of fertilizer (N, P and K) on growth of vinca ( Catharanthus roseus L. ) salvia ( Salvia splendens F. Sellow ex Roem.& Schult), Impatiens ( Impatiens wallerana Hook. f.) and petunia ( Pet unia X hybrida Hort. Vilm. Andr.) grown as plugs Plants were fertilized weekly in three separate experiments to quantify seedling response to N, P and K. Plants were fertilized with a nutrient solution containing 14, 28, 56, 112, or 224 mg L 1 N (with 31 mg L 1 P and 235 mg L 1 K); 3.9, 7.7, 15.5, 31, and 62 mg L 1 P (with 224 mM N and 238 313 mg L 1 K); or 19.5, 39, 78, 156, and 312 mg L 1 of K (with 224 mM N and 30 mg L 1 P). These rates were chosen according to common plug production practices (van

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33 Iersel et al., 1998a) The authors showed that P and K had no effect on growth of plugs for any species ; therefore, the application of these nutrients can be reduced (van Iersel et al., 1998b) Plug size for all species increased with increasing N rate However, the authors note that optimal size of bedding plants is hard to determine because quality of plugs is not only dependent on size but also seedling uniformi ty and plant height. (van Iersel et al., 1998a) Van Iersel et al. (1998b) looked at the effects of nutrition on pre and post transplant growth of petunia and i mpa tiens plugs. The seedlings were fertilized four times per week with nutrient solutions at the following N rates : 112, 224, 336, and 448 mg L 1 ; P and K were also applied at a rate of 31 and 39 mg L 1 respectively Both species had more rapid pre transplan t growth (stem length, leaf area, and shoot dry mass) when N was applied at the 336 and 448 1 rates Phosphorus and K fertilization had little effect on seedling growth. Post transplant growth was greatest when N was applied at rates of 224 336, or 4 1 N. The authors determined that the optimal tissue N concentration was 30 1 for petunia and 28 40 1 for impatiens The authors concluded that fertilization programs for production should focus on N response and that P and K fertil ization rates could be reduced (van Iersel et al., 1998a) Van Iersel et al. (1999) found that the shoot growth of s alvia and v inca seedlings (in plug trays) benefited from applications of N up to 448 1 N. While Tjia and Black (2003) recommended that a 2 lb ( 908 g)/100 ft 2 of a 5% nitrogen containing fertilizer be applied biweekly to begonias ( Begonia semperflorens Willd.) in a landscape A study was designed to determine growth respons e and foliar nutrient concentration of persian shield ( Strobilanthes dyerianus Mast) to different rates of N fertilizer (Gamrod and Scoggins, 2006) Rooted cuttings were transp lanted and fertilized with 0, 100, 200, 300, and 460

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34 1 N which w ere applied through constant liquid application. After eight weeks, plant dry mass, leaf area, and foliar tissue nutrient concentration were analyzed. The plants receiving fertilizer at the 200 mg L 1 N rate produced the most growth, but plant quality was unaffected by N fertilization rate (Gamrod and Scoggins, 2006) Romero (2006) evaluated the effects of N fertilizers applied at four N rates (3.5, 7, 10. 5, 1 ) at four ratios of NO 3 N: NH 4 + N (4:0, 3:1, 1:1, and 1:3) The experiment demonstrated that there was a significant statistical interaction between N concentration and source and most of the parameters (e.g. dry weights, flower bud nu mber, plant diameter, leaf number, and leaf chlorophyll content). Shoot fresh and dry weights and number of flower buds were max imized with 1:3 ratio of NO 3 :NH 4 + using an N concentration of 10.5 mmol L 1 (Romero et al., 2006) Plant diameter, leaf number and chlorophyll content had a quadratic response to NO 3 :NH 4 + form ratio ; a 1:1 ratio was optimum at a concentration of 10.5 mmol L 1 in t hese cases (Romero et al., 2006) Broschat (2001) determined the influence of substrate and fertilizer on five species of bedding plants grown in a greenhouse. Species included: s alvia ( Salvia splendens Tagetes patula Capsicum annum L. Impatiens wallerana begonia ( Begonia semperflorens cultorum were a 4 sedge peat:1 sand substrate or ProMix BX. Plants were fertilized weekly with 50 mL of a solution containing 100, 200, or 300 mg L 1 N from two sources (15 N 6.5 P 12.5 K or 21 N 3 P 11.7 K ) of uncoated prills used in the manufacture of controlled rele ase fertilizers P lant color, root and shoot dry mass and numbers of flowers or fruit for all species were correlated with N fertilizer rate. There

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35 were no significant substrate effects Broschat (2001) concluded that fertilizer source does not affect bedding plant quality. Response of Herbaceous Perennial s t o Nitrogen Fertilizer s Herbaceous perennial plants last for three years or longer in the landscape (Black and Tjia, 2000) The ter m is used to differentiate plant s from biennials and annuals. Similar to annual research most herbaceous perennial research was conducted under greenhouse conditi ons using young plant material. Most studies examined the specific nutritional requirements a nd fertilization needs of crops during production. As such, r esearch to determine perennial plant fertilization needs in the landscape is limited. Hipp et al. (1988) examined the influence of N and P on growth and tissue N and P concentrations of autumn sage ( Salvia greggii A.Gray. ) Plants were fertilized weekly at five N rates ( 12.5 25, 50, 100, 1 ) and three P rates ( 0 25 and 1 ) Maximum growth was achieved at when N was applied at a rate of 200 mg L 1 and P was applied at a rate of 50 1 ; plants receiving 150 1 N and 30 1 P had comparable growth The authors concl uded that tissue nutrient concentrations should be greater than 2.2% N and 0.20% P in order to not limit growth. Hipp et al. (1989) examined the influence of P on N fert ilizer requirement s of melampodium ( Melampodium leucanthum Torr. & A. Gray ) Plants received N at five rates ( 1 ) and P at three rates ( 0 15 and 1 ) Maximum growth was achieved when plants were fertilized with 1 1 P. The recommended rates were slightly lower than those reported for autumn sage suggesting that different plant species will have different fertilization requirements. Optimal growth occurred when leaf tissue N concentration was greater than 1.7% which was also lower than those for autumn sage (Hipp et al., 1988)

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36 Dubois et al. (2000) performed research on anemone ( Anemone hybrid a ) to determine the effect on N fertilizer rate 1 ) on the quantity of propagation material (leaf area, leaf dry mass, petiole and crown mass, and root mass) that could be produced. Optimal growth was achieved when a complete fertilizer applied was applied three times per w eek at an N rate of 150 1 ( ratio of 1 NH 4 + : 2 NO 3 ) The authors determined 1 These recommended rates fell within the range of 100 1 applied at every irrigation event or 100 150 1 applied weekly that are recommended for herbaceous perennials during production (Nau, 1996) Macz et al. (2001) determined if the addition of S could reduce the need for N fertilization of chrysanthemum ( Dendranthema grandiflora ) Nitrogen fertilizer rates were 50, 100, 150, or 200 mg L 1 with S rates of 0, 5, 10, 20, or 80 mg L 1 The authors concluded that the minimum acceptable rate of N was 100 mg L 1 when S was supplied at a rate of 10 mg L 1 This N rate produced commercial quality plant s and represented a minimum recommended rate to produce good quality chrysanthemum s Th e refore, fertilization with a combination of N and S could reduce production cost s and minimize the environmental impact of fertilization by reducing the amount of N applied to plants (Macz et al., 2001) Smith et al. (1998) performed a greenhouse study on ( Alstroemeria ) to determine optimal Ca and N rates. N itrogen was applied every 7 or 10 days at the following rates: 0 3.5, 7 14, 28.5 and 1 Calcium was applied at 0, 1, 2, 4, 8, and 12 1 Flower production increased with increasing N rate up to 1 Optimum N concentration in leaf tissue was 45 1 Maximum flower

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37 production was achieved when plants were fer 1. Ca lcium fertilization had no effect on flower production (Smith et al., 1998) Heever et al. (2008) examined the effects of N fertilization rate 1 ) and N source (NO 3 NH 4 + ) on the growth and medicinal properties of society garlic ( Tulbaghia violacea L ) grown in a 30 L pot filled with quartz s and The study was conducted in a greenhouse. Nitrate applications at a rate of 60 kg ha 1 produced more growth in terms of leaf number, leaf area and root and leaf dry mass than the other treatments However, antifungal activity of society garlic decrease d with N in nitrate form. Therefore the authors recommended applying both NO 3 and NH 4 + 1 to enhance growth and antifungal activity (van den Heever et al., 2008) This study show ed that N rates and forms may have affected the plant in ways other than growth. When h igh N rates are used to achieve optimal growth it could reduce heat tolerance attr act insects, or reduc e the time it takes the plant to complete its life cycle Broschat (2008) determine d the effect of fertilizer type on plant quality and plant tissue nutrient concentration inegrass ( Stenotaphrum secundatum (Walter)Kuntze Dypsis lutescens (H.Wendl.)Beentje & J.Dransf.), Canna generalis Pentas lanceolata (Forssk.)Deflers), allamanda ( Alla manda cathartica nandina ( Nandina domestica Thunb. ) in the landscape Fertilizers used in the study were a fertilizer with a high N: K ratio with no Mg, and several palm fertilizers with low N: K ratios and 100% of their N, K, and Mg i n controlled release form at the rate of 4.9 gm 2 N per applicati on (applicati on s were made quarterly) The exact same products were not used in each experiment as some materials became unavailable. Fertilizer s were substituted that had similar N: K ratio s and similar

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38 compositi on s. The authors found that st. augustinegrass nandina pentas and allamanda had similar visual quality ratings among treatments. In general, fertilizer type did not have a large effect on nutrient deficiency symptom severity or si ze of these plants. However, canna and areca palm receiving the 8N 0.9P 10.0K 4Mg palm fertilizer had higher quality ratings with than plants receiving the higher N : K ratio turf fertilizers (Broschat et al., 2008) S aha and Trenholm (2005) det ermine d the effect of fertilizer source on the water use of ornamentals and turf. The p s t. a ugustinegrass, canna, nandina, ligustrum, and allamanda Plants were grown in a greenhouse 300 L pots filled with Arredondo fine sand. T wo quick release fertilizers and one slow release fertilizer were applied at an N rate of 4.9 g m 2 every 60 d. Both turf and ornamental plants used less water and had higher water use efficiency when fertilized with a slow release N fertilizer. Th e authors showed that ornamental s pecies used 11 83% more water than turf (Saha et al., 2005) Research Objectives Many home owners strive to attain aesthetically pleasing landscapes (Israel and Knox, 2001) The average resident will err on the side of over application of fertilizer rather than insufficient application (Israel and Knox, 2001) About 10 60% of the nutrients applied in fertilizer end up in the plant being fertilized (Brady and Weil, 2002) .The excess nutrients may move off site due to high irrigation and precipitation rates to contaminate water systems (Brady and Weil, 2002) The ability of water to move through the sandy soils (that are common in most areas in Florida) adds to the susceptibility of nutrien t leaching (Brady & Weil 2002) (Brady and Weil, 2002) There is also generally, an increasing amount of impervious surfaces due to increasing urbanization that abet in the movement of excess nutrients to water bodies by limiting infiltration (Brabec et al., 2002) In order to insure that excess fertilizer is not applied to

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39 landscapes, accurate and specific fertilizer recommendations need to be created for ornamental plants. The basis for the current fertilizer recommendations for ornamental plants grown in the lan dscape in Florida is unclear. Sartain et al. (2009) mentions that shrub and tree fertilizer recommendations are based on 25 st udies that were conducted over the last 70 years. The recommendations resulting of this body of research, which was focused on trees and shrubs, was applied to all landscape plants. Trees and shrubs may have different fertilization requirements than other types of ornamental landscape plants (e.g., perennials, annuals, vines and groundcovers). Therefore, research needs to be done to validate the current fertilizer recommendations for a broader set of ornamental landscape plant types. Fertilizer rates effec t plant growth and development of annuals, perennials and woody ornamentals. However, more research needs to be performed in order to determine the optimum N fertilizer rates for these specific categories of plants when growing in the landscape, so that fe rtilizer recommendations correspond with the minimum amount of N needed for each of these plant types or families. Previous studies were mostly performed in a production situation, thus the results may differ when complete environmental control is limited. Ornamental plant nutritional requirements after establishment in the landscape are seldom documented. This study will determine some of these plant requirements. Knowledge of specific fertilization requirements will allow plants to be zoned in the landsc ape based on these requirements. This would be similar to the zoning recommendations for water requirements promoted by the Zoning plants based on fertilization requirements will result in more efficient fertilizer applicatio n, and should reduce

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40 nutrient losses to the environment. Today, as rapid population growth and development continues pollution from non point sources increases (Tang et al., 2005) The objective of this research is to determine the nitrogen (N) requirements of specific ornamental plants in order to create more precise N fertilization recommendations and to vali date current N fertilizer recommendations for annual and perennial plants grown in the landscape.

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41 CHAPTER 2 DETERMINATION OF NITROGEN REQUIR E MENTS FOR THREE SPECIES OF WARM SEASON ANNUALS Introduction The basis for current nitrogen (N) fertilizer recomm endations for ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs which may have different fertilization requirements than annual plants Therefore, the current fertilizer recommendations need to be validated for these additional plant types. Knowledge of specific fertilizer requirements will allow for zoning of plants within the landscape based on their N fertilizer requirements which should result in more efficient fertilizer application, th ereby r educing the potential for nutrient losses (e.g., runoff, leaching, and volatilization) to the environment. The objective of this study was to determine N fertilizer melampodium ( Melampodium divaricatum ) innia ( Zinnia elegans angustifolia ) ( Catharanthus roseus ) grown in the landscape in raised beds containing subsoil fill soil. Materials and Methods Plant Material Three warm season annuals, ( Zinnia elegans angustifolia Jacq. ) ( Catharanthus roseus L. ) ( Melampodium divaricatum (Rich.) DC. ) were selected based on anecdotal evidence of high, moderate, and low fertilization needs, respectively, for evaluation a cross a range of N edling, Inc. (Sun City, FL)

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42 During the 2008 season, plugs were transplanted on 24 25 Apr. 200 8 into 10.2 cm azalea pots (Reb Plastic Inc., Orlando, FL) filled with Verlite Vergo Mix A potting mix (Verlite Co., Tampa, FL) and grown in a greenhouse. The initial pH of the substrate ranged from 5.8 6.7 as determined using standard methods of the University of Florida Institute of Food and Agricultural Sciences (UF IFAS) Extension Soil Testing Laboratory (ESTL) (Mylavarapu, 2009) Plants wer e fertilized with a 20N 4.4P 16.6K fertilizer (Pete Lite Special, The Scotts 1 Plants were treated with i midicloprid (Marathon 60 WP, Olympic Horticultural Product TM, Mainland, PA) on 20 May 2008 to control white flies. On 30 May 2008, plants were moved from the greenhouse to an outside nursery to be hardened off, at which time the fertilizer was changed to a 21N 3.0P 5.8K (Acid special, The Scotts Company, Marysville, OH) applied twice a week at an N rate of 300 1 The N f ertilizer rate was increased to 1 N on 9 June 2008. A micronutrient blend (Soluble trace element mix, The Scotts Company, Marysville, OH) containing S, B, Cu, Fe, Mn, Mo, Zn was also applied weekly at the label r ate (0.5 lb/100 gal) until they were planted into the landscape plots. All plants were transplanted to the landscape beds on 10 11 June 2008. During the 2009 season, plugs were transplanted on 21 Apr. 2009 into 10.2 cm azalea pots (Reb Plastic Inc., Orl ando, FL) filled with Florida potting soils (Sun Grow Horticulture Distribution, Inc., Bellevue, WA) and grown in a greenhouse. Plants were fertilized biweekly using 21N 3.0P 5.8K (Acid special, The Scotts Company, Marysville, OH) at an N rate of 300 mg 1 A micronutrient blend (Soluble Trace Element Mix, The Scotts Company, Marysville, OH) containing S, B, Cu, Fe, Mn, Mo, Zn was also applied twice a week at the label rate (0.5 lb/100 gal) until they were planted into the landscape plots. The plants w ere moved from the

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43 greenhouse to the nursery on 22 June 2009 to be hardened off and planted into the landscape beds on 30 June 2009. Experimental Design Fifteen raised beds (3.08 m 12.19 m 0.15 m) were established at the University of Florida Institut e of Food and Agricultural Sciences (UF IFAS) Gulf Coast Research and Education Center in Wimauma, FL. The raised beds were filled with a St. Johns fine sand (USDA NRCS, 2004) collected from a depth of 21.34 m below the soil surface. This soil was represen tative of soil commonly used in construction areas of central Florida (USDA NRCS, 2004) The soil pH was adjusted using dolomitic lime (Sunniland lawn and garden lime, Sanford, FL) prior to planting and again on 4 Aug. 2009 (Table 2 1) Thirty six annual plants were planted in clusters within each rai sed landscape Each plant cluster contained three plants of the same species forming a triangle with individual plants spaced 0.31 m apart, for a total of 4 clusters per species per plot. am fertilizer recommendations for landscape plants (Florida Department of Environmental Protection, 2002) A polymer coated ammonium sulfate fertilizer (21N 0P 0K 24S, Honeywell Nylon, LLC, Seffner, FL) was applied at the following N rates: 0, 2, 4, 6 and 12 lb/1 000 ft 2 per yr (0, 9.8, 19.6, 2 per yr). Beds were not mulched to minimize outside N contributions. Other nutrients were applied at the same rate to all plots based on soil test and plant requirements based on UF IFAS recommendations (Kidder et al., 2009) Potassium (K) (0N 0P 41.5K, Great Salt Lake Minerals Corp., Overland Park, KS) was applied every four months at an N r ate of xx lb/1000 ft 2 per yr ( 22.5 gm 2 per yr ) (Kidder et al., 2009) A micronutrient fertilizer containing S, B, Cu, Fe, Mn, Mo and Zn (Scotts MicroMax, The Scotts Company, Marysville, OH) was

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44 applied to all plots on 23 July 2009 at the label recommended rate based on documented need for micronutrients by soil nutrient analysis. Irrigation was applied through nine drip lines (Jain Irriga tion, Inc., Winter Haven, FL) that were spaced 0.32 m apart with 0.20 m spacing between emitters and a flow rate of 0.65 gallons per minute /100 ft Plants were irrigated three times per week for 25 min at a rate of 1.80 cm of water applied per week starti ng at 0830 HR Cumulative rainfall and irrigation was 30.46 inches during the 2008 study period and 31.75 inches for the 2009 study period (University of Florida, 2010) (Tables 2 2 and 2 3 ). Weeds were removed man ually or spot treated with glyphosate (Round Up, Monsanto, Creve Coeur, MO). Soil Sampling and Analysis Eight soil cores were collected initially (0 weeks after planting ( WAP) and then every six weeks from each raised bed at a depth of 0 15 cm and composi ted. Samples were air dried and sieved to pass a 2 mm screen before analysis for pH, EC, lime requirement (Adams Evans buffer test) and Mehlich 1 extractions were performed using the standard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Mehlich 1 soil extracts were analyzed for P, K, Ca, Mg, Zn, Mn, Cu and Fe using inductively coupled plasma atomic emission spectroscopy. Initial soil nutrient content and results of periodic soil testing are reported in Appendix A Plant Growth and Shoot Dry Mass Plant growth measurements were taken at six week intervals and growth index (GI) was used as a quantitative indicato r of plant growth. Growth index was calculated as follows: GI (cm 3 ) = H W1 W2, where H is the plant he ight (cm), W1 is the widest width of the plant (cm), and W2 is the width perpendicular to the widest width (cm).

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45 Plant shoots were cut at the soil surface at 18 weeks after planting (WAP). Plant tissue (leaves and stems) were dried to a constant mass at 40 .5C and weighed to determine shoot dry mass (g). Plant Quality and Chlorophyll Content Aesthetic quality ratings were determined visually for each plant cluster at six week intervals. Quality ratings considered canopy density, flowers, chlorosis and dieb ack ; a quality rating of 1 indicating a poor quality plant (low canopy density, few no flowers, and chlorosis) and a quality rating of 5 indicating an outstanding plant (dense leaf canopy, a good presence, high quality flowers and no signs of nutrient defi ciencies or dieback) (Shober et al., 2009) Chlorophyll cont ent (SPAD) was determined every six weeks using a portable chlorophyll meter (SPAD 502, Minolta Corp., Ramsey, NJ). Six readings were taken per plant cluster (2 readings per plant) and averaged. Trends in SPAD measurements were correlated with results of c hlorophyll analysis using a spectrophotometer (Wang, 2004) Flower Cover Index Flower cover index was determined by taking overhead photographs of each plant cluster every six weeks (2009 season only). Color contrasts in the photographs were enhanced by altering the brightness using Adobe Photoshop Elements 6.0 (Adobe S ystems Inc. San Jose, CA). The background was removed using the cropping function. The photographs were then analyzed using a com puter image analysis system (WinFolia, 2007b for leaf analysis, Regent Instruments Inc. Quebec, Canada ). Color groups were created for flower s, foliage and the background. The Winfolia software assigned each pixel to one of the 3 color groups and calculat ed the percent area covered by each color group. Flower cover index was calculated as: Flower Cover Index (unitless) = Flower / (Flower + Canopy ) 100 where flower = the area covered by flowers and canopy = the area covered by canopy

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46 Foliar Nutrient C oncentration Analysis Composite samples of foliar tissue (mature leaves) from each plant cluster were taken at the termination of the experiment (24 Aug. 2009). Tissue samples were ground to pass a #20 screen using Wiley mill (Arthur H. Thomas Co Scientifi c, Philadelphia, PA) and dried at 110C for 7 d. Tissue digestions were completed using the standard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Digested samples were analyzed for total kjeldahl nitrogen (TKN) using an Alp kem autoanalyzer, and Ca, Mg, P, K, Na, Cu, Mn, Fe, Zn, and B using inductively coupled atomic absorption spectroscopy. Statistical Analysis Plant measurements were analyzed with SAS software, Version 9.2 (SAS Institute Inc. Cary, NC).Repeated measurement models were estimated using the MIXED procedure to test for overall differences on quantitative variables (e.g., GI, SPAD) across years, WAP and year WAP interacti ons with N fertilizer rates. A block diagonal covariance matrix with identical first order autoregressive structure (AR(1) ) on each block was specified. This structure incorporated correlation for all of the observations arising from the same experimental unit. After modeling the data across time, significant treatment year or WAP year inte ractions were found to be = 0.05) ; therefore detailed analyses within specific measurement weeks were performed using SPSS 17.0 (SPSS, Inc., Chicago, IL). General linear models (GLM) were estimated using N fertilizer rate as a fixed effect. All pairwise comparisons were completed = 0.05. Regression analysis was also performed for GI, SPAD and flower cover data using SPSS 17.0. The Pearson chi square statis tic was calculated in SPSS 17.0 (SPSS, Inc., Chicago, IL) to test the general association between plant quality ratings and N fertilizer rates.

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47 Results and Discussion Zinnia elegans angustifolia ) Plant growth and shoot dry mass In 2008, t here were no significant differences in growth (GI) between plants fertilized at the 4 6 or 12 lb/1000 ft 2 per yr rates at 6, 12 or 18 WAP. The plants receiving the three highest N rates were significantly larger t han plants receiving N at 0 or 2 lb/1000 ft 2 per year (Figure 2 1). In 2009, GI of zinnia differed significantly due to N fertilizer treatment at 6 WAP. Fertilization at 12 lb/1000 ft 2 per yr resulted in the most growth followed by 4 lb/1000 ft 2 per yr and 6 lb/1000 ft 2 per yr which w ere not significantly different from each other (Figure 2 2 a ) At 12 and 18 WAP, there were significant treatment effects on GI due to fertilizer treatments. Plants receiving fertilization at an N rate of 4 and 12 lb/1000 ft 2 per yr had the most growth an d were not significantly different from each other (Figure 2 2 b,c ) F ertilization at the 4 and 12 lb/1000 ft 2 per yr rates produced zinnia with significantly more biomass than plants receiving the other N rates in 2008 ( Figure 2 3 ). Plant quality and chlor ophyll content In 2008, there were differences in quality ratings due to N fertilizer treatments at 6 WAP. As N rate increased, quality rating also increased ( Table 2 4 ). At 12 WAP, there were significant differences in quality ratings due to N rate h owev er, the quality ratings did not increase with the addition of more N The 12 lb/1000 ft 2 per yr fertilizer rate resulted in plants with lower quality ratings than fertilization at the lower rates (4 and 6 lb/1000 ft 2 per yr ) (Table 2 4 ) It wa s possible th at the addition of N at high rates accelerated the life cycle of the plant s, forcing them into early decline which would be an undesirable result. Quality ratings for z innia at 18 WAP also reflect ed significant N treatment effects There was a large drop in quality for plants

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48 receiving N fertilizer, particularly with the highest N rate treatments P lants receiving N at the 4 lb/1000 ft 2 per yr rate were rated the highest, while quality ratings for plants receiving higher N rate s fell to u nsatisfactory levels ( T able 2 4 ). In 2009, there were differences in quality ratings due to N fertilizer treatments at 6 WAP ; where quality rating s increased with increasing N rate ( Table 2 4 ). At 12 WAP differences in quality due to N fertilizer treatmen ts persisted with the 6 and 12 lb/1000 ft 2 per yr producing plants with similar quality ratings ( Table 2 4 ) There was a large drop in quality for all plants regardless of N treatment by 18 WAP ( Table 2 4 ) A possible reason for the decline of Profusion z innia before 18 WAP could have been a result of high light intensity; the plants were grown in full and the flowers showed signs of sun damage (bleaching) In 2008, SPAD measurements for z innia at 6, 12, and 18 WAP were affected by N rate As expected, an increase in N fertilizer rate produce d an increase in chlorophyll within the plants (Figure 2 4 ). In 2009, SPAD measurements for z innia at 6 WAP show ed a significant N rate effect on plant chlorophyll There wer e no significant differences in SPAD measurements of plants receiving 4 6, or 12 lb/1000 ft 2 per yr (Figure 2 5 a ). At 12 WAP SPAD measurements of the plants receiving the fertiliz er at the N rate of 4 lb/1000 ft 2 per yr were not significantly different ( p 0.05) from the SPAD measurements of plants receiving N at the 12 lb/1000 ft 2 per yr rate (Figure 2 5 b ). There were no significant differences in SPAD measurements by treatments at 18 WAP (Figure 2 5c), which could be associated with decrease d plant qual ity at this time (Table 2 4) Flower cover index There was no significant N fertilizer effect on the flower cover index at 0, 6 or 18 WAP. At 12 WAP, the plants receiving the 0 lb/1000 ft 2 per yr treatment had a significantly lower

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49 flower cover index (m ean = 34.2%) than the plants receiving N at 4 or 6 lb/1000 ft 2 per yr ( 40.7%) (Table 2 5) Although there were significant N treatment differences, these differences were small and not detectable by the human eye. Therefore, it appeared that N level d id no t influence the ratio of flowers to canopy ; rather flower coverage was proportional to the size of the plant. For example, a small z innia plant had fewer flowers when compared with a larger plant, but the flowers cover ed an equal percenta ge of the respective canopies ( Table 2 5 ) Foliar nutrient concentration analysis Tissue levels of N in z innia reflected a strong N treatment effect where concentrations of N in the tissue significantly increas ed with increasing N rate ( Figure 2 6 ) Tissu e levels of K, Mg, Fe, and Zn were relatively constant (Table 2 6) w ith no significant differences due to N treatment (Data not shown) Tissue levels of Mn increased with N rate, while tissue levels of P indicated that P levels in plants receiving no N fe rtilizer were significantly higher than those receiving N ( data not shown ) Overall nitrogen requirement for zinnia During the first growing season, fertilization at N rates exceeding 4 lb/1000 ft 2 per yr did not significantly increase GI or SPAD ratings for zinnia During the second growing season, fertilization at N rates exceeding 4 lb/1000 ft 2 per yr did not significantly increase growth index and quality ratings for zinnia. Therefore, we suggest that fertilization with N at a rate of 4 lb/1000 ft 2 per yr consistently produced the best zinnia plants because growth was no longer limited by N availability.

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50 Catharanthus roseus ) Plant growth and shoot dry mass In both 2008 and 2009, GI for Cora White v inca was significantly different at 6, 12, and 18 WAP as a result of N fertilizer treatment Fertilization with N at 12 lb/1000 ft 2 per yr resulted in plants with the most growth (GI) followed by fertilization at the 6 and 4 lb/1000 ft 2 per yr rates (Figure 2 7 and 2 8 ) Shoot dry mass d ata indicate d for 2008 that dry tissue weight (g) increased with increas ing N rate The dry tissue weight was highest for plants fertilized at the 12 lb/1000 ft 2 per yr N rate (Figure 2 9 ). Plant quality and chlorophyll content In 2008, quality ratings for Cora White v inca differed significantly between plants due to N fertilizer treatments at 6, 12, and 18 WAP. An increase in N resulted in an increase in plant quality rating s ( Table 2 4 ) Quality of the plants receiving n o fertilization ( 0 lb/1000 ft 2 pe r yr ) was negative ly a ffect ed ( Table 2 4 ) At 12 WAP, plants receiving 0 and 2 lb/1000 ft 2 per yr received sub satisfactory quality ratings At 18 WAP, 100% of the plants receiving the two highest fertilization treatments ( 6 and 12 lb/1000 ft 2 per yr ) were rated at as above average or outstanding (4 or 5). Overall, quality ratings seemed to increase over time for the three lowest treatments. For example, the median quality rating for vinca at 6, 12 and 18 WAP was 2, 2.5, and4 respectively Based on these pl ant quality trends, we r esults suggest ed that v inca do require N fertilization to produce acceptable quality plants However, the increase in N probably accelerated the rate at which vinca plant s reache d higher quality ratings compared with plants receivi ng l ower fertilizer rates (Table 2 4 ) In 2009, quality ratings for Cora W v inca differed significantly due to N fertilizer rate at 6, 12, and 18 WAP. As in 2008, an increase in N fertilization produced an increase in plant

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51 quality (Table 2 4) At 6 WAP, 100% of the plants receiving fertilization at the rate of 12 lb/1000 ft 2 per yr were rated as satisfactory or above. However, around 90% of the plants receiving N fertiliz er at 4 and 6 lb/1000 ft 2 per yr were rated satisfactory or above ( Table 2 4 ) A t 12 WAP, N fertilization at 4, 6, and 12 lb/1000 ft 2 per yr all produced satisfactory or above ratings for more than 90% of all plants Fertilization with 12 lb/1000 ft 2 per yr produced a higher percentage of outstanding ratings ; however, fertilization wi th 6 lb/1000 ft 2 per yr N produced 100% with plant quality ratings that were satisfactory or above ( Table 2 4 ) At 18 WAP, the quality ratings of plants in all treatments declined sharply, but the 12 lb/1000 ft 2 per yr N rate resulted in the highest percen tage of plants with satisfactory or above ratings ( Table 2 4 ). In both 2008 and 2009, SPAD measurements of Cora W v inca at 6, 12 and 18 WAP differed among treatments (Figures 2 10 and 2 11) As expected, an increase in N rate produce d an increase in chlorophyll within the plants There were no significant differences between SPAD readings at the 6 and 12 lb/1000 ft 2 per yr rates (F igures 2 10 and 2 11 ) Flower cover index Flower cover index results for Cora W v inca indicated that there was no s ignificant difference due to N treatment at 0 or 6 WAP (Table 2 5 ) However, there were significant differences in flower cover index due to N treatments at 12 and 18 WAP (Table 2 5) At 12 WAP, the plants receiving the N at the 12 lb/1000 ft 2 per yr rate had significantly lower flower coverage ind ex compared with plants receiving 0, 2 or 4 lb/1000 ft 2 per yr (Table 2 5) Also, plants receiving 6 lb/1000 ft 2 per yr N had significantly lower flower coverage indices compared to plants that received no N fert ilizer ( 0 lb/1000 ft 2 per yr ) (Table 2 5) For 18 WAP, plants receiving 2 lb/1000 ft 2 per yr N had significantly higher flower coverage indices compared with plants receiving 4 and 12 lb/1000 ft 2 per yr (Table 2 5) Although there were significant differen ces in flower coverage indices due to N treatments at both 12 and 18 WAP, these

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52 differences were no more than 8.29% which was probably not enough to be detected by the human eye in a landscape setting Foliar nutrient concentration analysis T issue levels of N in Cora White v inca showed strong treatment effects with N tissue concentration significantly increasing with N treatment (Figure 2 12 ) Tissue levels of Mg and Zn were relatively constant with no significant differences in relation to treatment (Da ta not shown) Tissue levels of Mn and Fe increased with N while tissue levels of P and K decreased with N (Data not shown) The tissue nutrient concentration levels observed for vinca in our study were similar to the normal range provided by Mills and Jo nes (1996) (Table 2 7). Overall nitrogen requirement for vin ca Growth index shoot dry mass and SPAD measurement were highest in both years when 12 lb/1000 ft 2 per yr rate However, fertilization with N at 6 and 12 lb/1000 ft 2 per yr resulted in above average quality ratings Overall, we suggest a n N fertilizer requirement of 12 lb/1000 ft 2 per yr for Cora White v inca This suggested N requirement is double the highest rate recommended by the Florida lants growing in th e landscape. Therefore, i t is important that the environmental effects of these fertilizing ornamental plants at high N rates reduced in more fertile soils. As such, it is importa nt to validate the results of this study in different soil types to allow for the development of more precise fertilizer recommendations. ( Melampodium divaricatum ) Plant growth and shoot dry mass In 2008, GI for me lampodium differed significantly due to N fertilizer treatments at 6 and 12 WAP. At 6 WAP plants receiving no N fertilizer ( 0 lb/1000 ft 2 per yr )

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53 were significantly smaller then plants receiving all other N treatments (Figure 2 13 a ) At 12 WAP, plants re ceiving no N fertilizer ( 0 lb/1000 ft 2 per yr ) were significantly smaller then plants receiving N at the 2 lb/1000 ft 2 per yr rate; a ll other treatment results were not significantly different from one another (Figure 2 13 b ) By 18 WAP, most plants reached the end of their life cycle ( regardless of the N fertilizer treatment ) and were therefore excluded from the study (Figure 2 13 c ) In 2009 GI for melampodium differed significantly due to fertilizer treatments at 6 and 12 WAP. Fertilization with N at the 4, 6, and 12 lb/1000 ft 2 per yr rates resulted in the most growth at 6 WAP with no significant differences in the GI of plants between these rates (Figure 2 14 ) At 12 WAP the GI of all plant s receiving N fertilizer did not differ significa ntly from each other but all had higher GI than unfertilized plants (Figure 2 14 ) By 18 WAP most plants had reached the end of their life cycle ( regardless of N fertilizer rate ) and were excluded from the study. Shoot dry mass was not determined for me lampodium because the plants had reached the end of their life cycle prior to 18 WAP. Plant quality and chlorophyll content In 2008 quality ratings for melampodium at 6 WAP appeared to increase with increasing N rate The plants with the hi ghest quality ratings were fertilized with N at 4, 6, or 12 lb/1000 ft 2 per yr ( Table 2 4 ) At 12 WAP there was a severe decline in quality for all plants, which indicate d that the plants were approaching the end of their life cycle. Plants f ertiliz ed wit h N at 2, 4, or 6 lb/1000 ft 2 per yr maintained the highest quality ratings (Table 2 4). By 18 WAP the quality ratings of nearly all the plants were below satisfactory (>3) because the plants had reached the end of their life cycle and were no longer of a esthetic value (Table 2 4).

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54 In 2009 quality ratings for melampodium at 6 WAP appeared to increase with increasing N rate The N fertilization rate of 12 lb/1000 ft 2 per yr produced plants with the highest quality ratings; h owever fertiliza tion at the 4 and 6 lb/1000 ft 2 per yr N rates resulted in 90% of plants rated were satisfactory or above (Table 2 4). At 12 WAP there was a severe decline in quality for plants fertilized with 12 lb/1000 ft 2 per yr N, which indicate d that high rates of N fertilizer accelerated the life cycle of melampodium In contrast, the f ertilization treatments that produced plants with the highest quality ratings were 2 4, or 6 lb/1000 ft 2 per yr (Table 2 4). By 18 WAP the quality ratings of nearly all plants were below satisfactory levels (>3) because t he plants reached the end of their life cycle and were no longer of aesthetic value (Table 2 4). In 2008 SPAD measurement s for melampodium at 6 WAP increase d in with increasing N fertilizer rate (Figu re 2 15a ) However, there was no increase in chlorophyll content when plants were fertilized with N at rates exceeding 4 lb/1000 ft 2 per yr (Figure 2 15a ) At 12 WAP there wa s also a significant N treatment effect however, the differences were smaller th en at 6 WAP and did not follow the trend of increased chlorophyll with increasing N rate Th erefore, we suggest that by 12 WAP plant phenology may have a larger effect on the chlorophyll content than N fertilization rate (Figure 2 15 ) In 2009 SPAD measur ements for melampodium at 6 WAP increase d along with N fertilizer rate (Figure 2 16a). The SPAD measurements were highest for plants receiving N at the 12 lb/1000 ft 2 per yr rate followed by plants f ertiliz ed at the 4 and 6 lb/1000 ft 2 per y r rates, which were not significantly different from each other (Figure 2 16a ) At 12 WAP there wa s also a significant N fertilizer effect on SPAD but there was no significant difference between plants receiving 12 lb/1000 ft 2 per yr N or unfertilized p lants (Figure 2 16b) Th erefore,

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55 we suggested that the addition of N fertilizer ceased to influenc e SPAD measurements by 12 WAP (Figure 2 16 ) Flower cover index Flower cover index results for melampodium indicated no significant N fertilize r effect at 0 WAP. At 6 WAP unfertilized plants had significantly lower flower cover index than plants receiving N at the 6 and 12 lb/1000 ft 2 per yr rates (Table 2 5 ) At 12 WAP the flower cover index for unfertilized plants wa s significantly lower than for plants fertiliz ed with N at the 4, 6, and 12 lb/1000 ft 2 per yr rates (Table 2 5) However, flower cover index did not exceed 10% for all treatments and thus it is unlikely that treatment fertilization would greatly affect aesthetics in the landscape ( Table 2 5 ) Overall nitrogen requirement for melampodium Overall, based on 2008 and 2009 data, nitrogen requirements for melampodium are 4 lb/1000 ft 2 per yr It wa s clear from the GI and quality results that melampodium requ ire d the addition of some N fertilizer but it app e are d that the highe st rates (6 and 12 lb/1000 ft 2 per yr) d id not improve growth or growth and quality. It was interesting to note that in both years of the study the life span melampod ium did not extend beyond 12 WAP regardless of N fertilizer treatments. By 18 WAP all plants receiving had deteriorated past the point of usefulness in the landscape in terms of quality and that the decline in quality cannot be attributed to N treatment. One factor that may have affected the life span of melampodium was infestation of most melampodium root zone with fire ants The reasons for this were unclear but th e fire ant colonies could have negatively affected the health of the plant s or their root systems. Another reason for early decline of mealmpodium could be simply that the se plants had a shorter life span than other species when grown under the conditions of the experiment.

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56 Figure 2 1. Growth measuremen ts of z innia ( Zinnia elegans angustifolia ) grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. Mean separation by P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) a AB AB A B C C b AB A A B B c AB A A B B Annual N Fertilizer Rate (per 1000 ft 2 )

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57 Figure 2 2. Growth measurements of z innia ( Zinnia elegans angustifolia grown in raised landscape beds (2009) and f ertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. bars indicate the 95% confidence interval Mean Growth Index (cm 3 ) a A B B C D b A BC AB C D c A BC AB BC C Annual N Fertilizer Rate (per 1000 ft 2 )

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58 Figure 2 3. Shoot dry mass of Zinnia ( Zinnia elegans angustifolia in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. bars indicate the 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) A AB B B C Mean D ry Shoot (g)

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59 Figure 2 4 SPAD measurements of Zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2008) and fertilized with at five N rat es for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. bars indicate the 95% confidence interval. Mean SPAD Measurement a A A AB BC C b A AB ABC BC C Annual N Fertilizer Rate (per 1000 ft 2 )

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60 Figure 2 5 SP AD measurements of Zinnia ( Zinnia elegans angustifolia grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. Mean P bars indicate the 95% confidence interval. Mean SPAD Measurement a A AB AB BC C b A B AB B B c A B AB AB AB Annual N Fe rtilizer Rate (per 1000 ft 2 )

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61 Figure 2 6 Tissue concentrations of total Kjeldahl N (TKN) collected at 18 weeks (2009) after planting for z innia ( Zinnia elegans angustifolia plants grown in rais ed landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A B B B B Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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62 Figure 2 7 Growth indices of v in ca ( Catharanthus roseus landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. bars indicate the 95% confidence interval Mean Growth Index (cm 3 ) a A AB B BC C b A B C C D c A AB BC C D Annual N Fertilizer Rate (per 1000 ft 2 )

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63 Figure 2 8 Growth indices of v inca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) a A B C C D b A B B C CD D c A B B C D Annual N Fertilizer Rate (per 1000 ft 2 )

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64 Figure 2 9. Shoot dry mass (g) o f v inca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. P bars indicate t he 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) A B C D D Mean Dry Shoot (g)

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65 Figure 2 10 SPAD measurements of v inca ( Catharanthus roseus landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planti ng (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean SPAD Measurement a A AB B C C b A AB BC BC C c A BC B C D Annu al N Fertilizer Rate (per 1000 ft 2 )

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66 Figure 2 11 SPAD measurements of v inca ( Catharanthus roseus landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean SPAD Measurements c A B B B B b A B B B B a A B BC C D Annual N Fertilizer Rate (per 1000 ft 2 )

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67 Figure 2 12 Tissue concentrations of total Kjeldahl N (TKN) of v inca ( Catharanthus roseus rates for 18 weeks in USDA hardiness zone 9b. P 5. Error bars indic ate the 95% confidence interval A B C C C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent (p 1000 ft 2 )

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68 Figure 2 13 Growth indices of melampodium ( Melampodium grown in raised landscape beds (2008) and fertilized with at five N rates for 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) a A A A A B b A AB A B AB B Annual N Fertilizer Rate (per 1000 ft 2 )

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69 Figure 2 14 Growth indices of melampodium ( Melampodium divaricatu grown in raised landscape beds (2009) and fertilized with at five N rates for 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. P 5. Error bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) a A A A B B C b AB A A AB B Annual N Fertilizer Rate (per 1000 ft 2 )

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70 Figure 2 15 SPAD measurements of melampodium ( Melampodium 12 weeks in USDA ha rdiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. P bars indicate the 95% confidence interval. Mean SPAD Measurements b A AB B AB B a A A A B B Annual N Fertili zer Rate (per 1000 ft 2 )

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71 Figure 2 16 SPAD measurements of melampodium ( Melamp odium 12 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP) and b) 12 WAP. test at P bars indicate the 95% confidence interval. Mean SPAD Measurements a A B BC CD D b A B B AB A Annual N Fertilizer Rate (per 1000 ft 2 )

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72 Table 2 1. Soil pH, Adams Evans pH, lime requirements and amou nt of lime applied for St. John s fill soil used in raised beds for the evaluation of N fertilizer requirement of landscape grown orname ntal plants. Annual N fertilizer rate (lb N/1000 ft 2 ) Soil pH Adams Evans b uffer pH Recommended lime 1 ) Lime applied z (kg) 0 6.27 7.67 1.70 6.32 2 6.08 7.61 1.90 7.06 4 6.18 7.64 1.47 5.45 6 5.98 7.64 2.00 7.43 12 5.50 7.61 3.17 11.8 z L ime applied 4 Aug. 2009

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73 Table 2 2. Total irrigation and rainfall volumes applied to warm season annual plant species grown in raised beds in USDA hardiness zone 9b between June 2008 and October 2008. Week Irrigation (in/week) Rainfall total z (in/week) I rrigation + rainfall (in) Cumulative rainfall (in) 1 0.71 2.66 3.37 3.37 2 0.71 2.36 3.07 6.44 3 0.71 0.33 1.04 7.47 4 0.71 3.15 3.86 11.3 5 0.71 2.31 3.02 14.4 6 0.71 0.94 1.65 16.0 7 0.71 1.45 2.16 18.2 8 0.71 0.51 1.22 19.4 9 0.71 2.66 3.37 22. 7 10 0.71 0.00 0.71 23.5 11 0.71 0.11 0.82 24.3 12 0.71 0.33 1.04 25.3 13 0.71 0.04 0.75 26.1 14 0.71 0.38 1.09 27.1 15 0.71 0.41 1.12 28.3 16 0.71 0.06 0.77 29.0 17 0.71 0.72 1.43 30.5 z Rainfall data collected at 2 m from the Florida Automated W eather Network station located approximately 805 m from the planting s ite (University of Florida, 2010)

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74 Table 2 3. Total irrigation and rainfall volumes applied to warm season annual plant species grown in ra ised beds in USDA hardiness zone 9b between April 2009 and August 2009. Week Irrigation (in/week) Rainfall total z (in/week) Irrigation + rainfall (in) Cumulative rainfall (in) 1 0.71 0.00 0.71 0.71 2 0.71 0.00 0.71 1.42 3 0.71 0.00 0.71 2.12 4 0.71 0.0 0 0.71 2.83 5 0.71 3.06 3.77 6.60 6 0.71 3.23 3.94 10.5 7 0.71 2.47 3.18 13.7 8 0.71 0.26 0.97 14.7 9 0.71 0.69 1.40 16.1 10 0.71 1.37 2.08 18.2 11 0.71 0 .00 0.71 18.9 12 0.71 1.98 2.69 21.6 13 0.71 0.35 1.06 22.6 14 0.71 1.7 0 2.41 25.0 15 0.71 0.58 1.29 26.3 16 0.71 1.03 1.74 28.0 17 0.71 0.95 1.66 29.7 18 0.71 1.34 2.05 31.8 z Rainfall data collected at 2 m from the Florida Automated Weather Network station located approximately 805 m from the planting s ite (University of Florida, 2010)

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75 Table 2 4 Median visual quality ratings for Zinnia elegans 'Profusion Cherry' Catharanthus roseus 'Cora White' and Melampodium divaricatum 'Golden Globe' grown in raised landscape beds and fertilized at five N rates for 18 weeks (2008 and 2009) in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000ft 2 ) Plant quality rating Season 1 Season 2 0 WAP z 6 WAP 12 WAP 18 WAP 0 WAP 6 WAP 12 WAP 18 WAP Zinnia elegans 'Profusion Cherry' (z innia) 0 5 5 5 5 5 5 5 5 2 5 5 5 5 5 5 5 5 4 5 5 5 5 5 5 5 5 6 5 5 5 5 5 5 5 5 12 5 5 5 5 5 5 5 5 Catharanthus roseus 'Cora White' (v inca) 0 5 1 1.5 2 5 2 2 2 2 5 2 2.5 4 5 2.5 3 2 4 5 3 3 4 5 3 3 2 6 5 4 4 4 5 3 4 2.5 12 5 5 5 5 5 4 4 3 Melampodium divaricatum 'Golden Globe' (m elampodium) 0 5 1 2 1 5 2 2.5 -2 5 3 3 1 5 3 3 -4 5 4 3 1 5 3 3 -6 5 4 3 1 5 3 4 -12 5 4 2 1 5 4 1.5 -z WAP = week after planting

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76 Table 2 5 Mean flower cover indices for Zinnia elegans 'Profusion Cher ry' Catharanthus roseus 'Cora White' and Melampodium divaricatum 'Golden Globe' grown in raised landscape beds and fertilized at five N rates for 18 weeks (2009) in USDA hardiness zone 9b Annual N fertilizer rate (lb/1000ft 2 ) Flower cover index z 6 WA P y 12 WAP y 18 WAP y Zinnia elegans 'Profusion Cherry' (z innia) 0 53.0 a 34.2 b 27.9 a 2 55.4 a 40.4 ab 37.8 a 4 56.0 a 40.7 a 38.3 a 6 55.3 a 40.7 a 32.9 a 12 52.9 a 38.7 ab 39.8 a Catharanthus roseus 'Cora White' (v inca) 0 36.7 x a 26.0 a 11.8 ab 2 37.5 a 25.1 ab 9.25 b 4 38.0 a 25.1 ab 12.4 a 6 40.1 a 20.7 bc 10.7 ab 12 39.1 a 17.7 c 12.2 a Melampodium divaricatum 'Golden Globe' (m elampodium) 0 17.6 c 20.6 c -2 19.6 bc 22.9 bc -4 20.7 abc 29.0 a -6 23.4 a 30.3 a -12 22.9 ab 27.6 ab -z Flower cover index = Flower/ (Flower + Canopy)*100 y WAP = week after planting x

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77 Table 2 6 Leaf tissue nutrient concentrations from tissue collected at 18 weeks after planting (2009) from Zinnia elegans in USDA hardiness zone 9b compared with published values. Element Zinnia elegans published analysis z Zinnia elegans r ange N, % 5.70 1.20 2.00 P, % 0.74 0.22 0.32 K, % 3.25 1.08 1.47 Ca, % 2.37 1.98 2.42 Mg, % 1.48 0.33 0.41 Fe, mg 1 81.0 259 475 1 300 99.2 256 1 115 27.6 37.3 z Values reported are for Zinnia elegans in a greenhouse production setting (Mills and Jones, 1996)

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78 Table 2 7 Leaf tissue nutrient concentrations from tissue collected at 18 weeks after planting (2009) from Catharanthus roseus in USDA hardiness zone 9b compared with published values. Element Catharanthus roseus published analysis z Vinca 'Cora White' r ange N, % 2.72 6.28 2.0 2.5 P, % 0.28 0.64 0.4 0.72 K, % 1.88 3.48 1.08 2.19 Ca, % 0.93 1.13 2.58 3.23 Mg, % 0.32 0.78 0.44 0.56 1 72.0 277 91.0 143 1 135 302 143 388 1 30.0 51.0 62.3 81.3 z Values reported are for Catharanthus roseus in a greenhouse production setting (Mills and Jones, 1996)

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79 CHAPTER 3 DETERMINATION OF NITROG EN REQUIR E MENTS FOR THREE SPECIES OF COOL SEASON ANNUALS Introduction The basis for current nitrogen (N) fertilizer recommendations for ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs which may h ave different fertilization requirements than annual plants Therefore, the current fertilizer recommendations need to be validated for these additional plant types. Knowledge of specific fertilizer requirements will allow for zoning of plants within the l andscape based on their N fertilizer requirements which should result in more efficient fertilizer application, th ereby reducing the potential for nutrient losses (e.g., runoff, leaching, and volatilization) to the environment. The objective of this study s napdragon ( Antirrhinum majus ) d ianthus ( Dianthus chinensis ) and p ansy ( Viola wittrockiana ) grown in the landscape in raised beds containing subsoil fill soil. Mat erials and Methods Plant Material s napdragon ( Antirrhinum majus ) d ianthus ( Dianthus chinensis ) and p ansy ( Viola wittrockiana ) were selected based on anecdotal evidence of h igh, moderate, and low fertilization needs (respectively) for evaluation across a ra nge of N fertilization regimes. In 2008, plants were received as plugs in a 288 tray size from Knox Nursery (Winter Garden, FL). plugs were transplanted on 29 Sept 200 8 in to 10.2 cm azalea pots (Reb Plastic Inc., Orlando, FL) filled with Verlite Vergo Mix A potti ng mix (Verlite Co., Tampa, FL) and

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80 g rown in a greenhouse. Plants were fertilized twice a week with 21N 3.0P 5.8K (Acid Special, The Scotts Company, Marysville, OH) + micronutrients (Soluble Trace Element Mix, The Scotts Company, Marysville, OH) at a n N 1 N f or three weeks and at an N rate of 500 1 N for the last two weeks All plants were planted into the landscape beds in a completely ran domize d design on 10 Nov. 2008 In 2009, napdragon and d ianthus were received as plugs in a 288 count p ansy plugs were received in a 144 count tray s from Knox Nursery (Winter Garden, FL). Plugs we re transplanted on 29 Sept 2009 into 10.2 cm a zalea pots (Reb Plastic Inc., Orlando, FL) filled with Faf a rd 2 Mix Professional Formula (Syngenta Group Company, Agawam, M A ) and grown in a shadehouse (54.5% shade) for six weeks. While in the shadehouse, d ia nthus and s napdragons were fertilized with 21N 3.0P 5.8K (Acid Special, The Scotts Company, Marysville, OH) + micronutrients (Soluble Trace Element Mix, The Scotts Company, Marysville, OH) at a n N 1 for one week then at an N rate of 500 m 1 until they were ready to be transplanted into the treatment plots. Pansies were fertilized with a 21N 3.0P 5.8K (Acid Special, The Scotts Company, Marysville, OH) + micronutrients (Soluble Trace Element Mix, The Scotts Company, Marysville, OH) at an N rate 1 N for the first two weeks and then at an N rate of 1 N until they were ready to be transplanted into the raised landscape beds All plants were planted into the landscape beds in a completely randomized design on 16 Nov. 2009. Cool season annuals were treated with pest icides as indicated in (Table 3 1). Experimental Design Fifteen raised beds (3.08 m 12.19 m 0.15 m) were established at the University of Florida Institute of Food and Agricultural Sciences (UF IFAS) Gulf Coas t Research and Education Center in Wimauma, FL. The raised beds were filled with a St. Johns fine sand

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81 (USDA NRCS, 2004) collected from a depth of 21.34 m below the soil surface. This soil was representative of soil commonly used in const ruction areas of central Florida (USDA NRCS, 2004) The soil pH was adjusted using dolomitic lime (Sunniland lawn and garden lime, Sanford, FL) prior to planting an d again on 4 Aug. 2009 (Table 2 1). Thirty six annual plants were planted in clusters within each raised landscape Each plant cluster contained three plant s of the same species forming a triangle with individual plants spaced 0.31 m apart, for a total of four clusters per species per plot. fertilizer recommendations for landscape plants (Florida Department of Environmental Protection, 2002) For the first season, a polymer coated ammonium sulfate fertilizer (21N 0P 0K 24S, Honeywell Nylon, LLC, Seffner, FL) was applied at the following N rates: 0, 2, 4, 6 and 12 lb/1000 ft 2 per yr (0, 9.8, 19.6, 2 per yr). For the second season, a polymer coated urea (42N 0P 0K, Lakeland, FL) was applied at the following N rates: 0, 2, 4, 6 and 12 lb/1000 ft 2 per yr (0, 2 per yr) Beds were not mulched to minimize o utside N contributions. Other nutrients were applied at the same rate to all plots based on soil test and plant requirements based on UF IFAS recommendations (Kidder et al., 2009) Potassium (K) (0N 0P 41.5K, Great Salt Lake Minerals Corp., Overland Park, KS) was applied every four months at an N rate of xx lb/1000 ft 2 per yr ( 22.5 gm 2 per yr ) (Kidder et al., 2009) A micronutrient fertilizer containing S, B, Cu, Fe, Mn, Mo and Zn (Scotts MicroMax, The Scotts Company, Marysville, OH) was applied to all plots on 23 July 2009 at the label recommended rate based on documented need for micronutrients by soil nutrient analysis. Irrigation was applied through nine drip lines (Jain Irrigation, Inc., Winter Haven, FL) that were spaced 0.32 m apart with 0.20 m spacing between emitter s and a flow rate of 0.65 gallons

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82 per minute /100 ft Plants were irrigated three times per week for 25 min at a rate of 1.80 cm of water applied per week starting at 0830 HR Cumulative rainfall and irrigation was 30.46 inches during the 2008 study period and 31.75 inches for the 2009 study period (University of Florida, 2010) (Tables 2 2 and 2 3). Weeds were removed manually or spot treated with glyphosate (Round Up, Monsanto, Creve Coeur, MO). Soil Sampling and Analysis Eight soil cores were collected initially (0 weeks after planting (WAP) and then every six weeks from each raised bed at a depth of 0 15 cm and composited. Samples were air dried and sieved to pass a 2 mm screen before analysis for pH, EC, lime r equirement (Adams Evans buffer test) and Mehlich 1 extractions were performed using the standard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Mehlich 1 soil extracts were analyzed for P, K, Ca, Mg, Zn, Mn, Cu and F e using inductively coupled plasma atomic emission spectroscopy. Initial soil nutrient content and results of periodic soil testing are reported in Appendix A. Plant Growth and Shoot Dry Mass Plant growth measurements were taken at six week intervals and growth index (GI) was used as a quantitative indicato r of plant growth. Growth index was calculated as follows: GI (cm 3 ) = H W1 W2, where H is the plant height (cm), W1 is the widest width of the plant (cm), and W2 is the width perpendicular to the w idest width (cm). Plant shoots were cut at the soil surface at 18 weeks after planting (WAP). Plant tissue (leaves and stems) were dried to a constant mass at 40.5C and weighed to determine shoot dry mass (g).

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83 Plant Quality and Chlorophyll Content Aesthet ic quality ratings were determined visually for each plant cluster at six week intervals. Quality ratings considered canopy density, flowers, chlorosis and dieback ; a quality rating of 1 indicating a poor quality plant (low canopy density, few no flowers, and chlorosis) and a quality rating of 5 indicating an outstanding plant (dense leaf canopy, a good presence, high quality flowers and no signs of nutrient deficiencies or dieback) (Shober et al., 2009) Chlorophyll content (SPAD) was determined every six weeks using a portable chlorophyll meter (SPAD 502, Minolta Corp., Ramsey, NJ). Six readings were taken per plant cluster (2 readings per plant) and averaged. Trends in SPAD measurements were correlated with results of chlorophyll analysis using a spectrophotometer (Wang, 2004) Flower Cover Index Flower cover index was determined by taking overhead photographs of each plant cluster every six weeks (2009 season only). Color contrasts in the photographs were enhanced by altering the brightness using Adobe Photoshop Elements 6.0 (Adobe S ystems Inc. San Jose, CA). The background was removed using the cropping function. The photographs were then analyzed using a computer image analysis system (WinFolia, 2007b for leaf analysis, Regent Instruments Inc. Quebec Canada ). Color groups were created for flower s, foliage and the background. The Winfolia software assigned each pixel to one of the 3 color groups and calculated the percent area covered by each color group. Flower cover index was calculated as: Flower Cover Index (unitless) = Flower / (Flower + Canopy) 100 where flower = the area covered by flowers and canopy = the area covered by canopy Foliar Nutrient Concentration Analysis Composite samples of foliar tissue (mature leaves) from each plant cluste r were taken at the termination of the experiment (24 Aug. 2009). Tissue samples were ground to pass a #20

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84 screen using Wiley mill (Arthur H. Thomas Co Scientific, Philadelphia, PA) and dried at 110C for 7 d. Tissue digestions were completed using the st andard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Digested samples were analyzed for total kjeldahl nitrogen (TKN) using an Alpkem autoanalyzer, and Ca, Mg, P, K, Na, Cu, Mn, Fe, Zn, and B using inductively coupled atomic absorption spectroscopy. Statistical Analysis Plant measurements were analyzed with SAS software, Version 9.2 (SAS Institute Inc. Cary, NC).Repeated measurement models were estimated using the MIXED procedure to test for overall differences on quantitative variables (e.g., GI, SPAD) across years, WAP and year WAP interactions with N fertilizer rates. A block diagonal covariance matrix with identical first order autoregressive structure (AR(1)) on each block was specified. This structure incorporated corre lation for all of the observations arising f rom the same experimental unit. After modeling the data across time, significant treatment year or WAP year interactions were found to be = 0.05) ; therefore detailed analyses within specific me asurement weeks were performed using SPSS 17.0 (SPSS, Inc., Chicago, IL). General linear models (GLM) were estimated using N fertilizer rate as a fixed effect. All pairwise comparisons were completed with = 0.05. Regression analysis was also performed for GI, SPAD and flower cover data using SPSS 17.0. The Pearson chi square statistic was calculated in SPSS 17.0 (SPSS, Inc., Chicago, IL) to test the general association between pla nt quality ratings and N fertilizer rates.

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85 Results and Discussion Dianthus chinensis ) Plant growth and shoot dry mass In 2008 2009, GI increased with N fertilization rates at 6, 12 and 18 WAP. At 6 WAP the 4 6, or 12 lb/1000 ft 2 per yr N were not si gnificantly different (Figure 3 1 a ). At 12 and 18 WAP there were no significantly differen ces in the GI of plants fertiliz ed with 6 or 12 lb/1000 ft 2 per yr N (Figures 3 1 b and c ). Thus, we suggest that a fertilization rate of 6 lb/1000 ft 2 per yr was appropriate for dianthus during the first growth season In 2009 2010, there were no N fertilizer treatment effects on GI at 6 WAP (Figure 3 2 a ). At 12 WAP the GI increased with increa sing fertilization rate. Fertilization of dianthus at the 6 lb/1000 ft 2 per yr did not produce plants with significantly different GI than fertilization with N at the 12 lb/1000 ft 2 per yr rate (Figure 3 2 b ). At 18 WAP GI increased with increasing fertil ization rate where plants fertilized at the 6 and 12 lb/1000 ft 2 per yr N rate were significantly larger than plants fertilized at the 0, 2, or 4 lb/1000 ft 2 per yr (Figure 3 2 c ). Thus, we suggested that a fertilization rate of 6 lb/1000 ft 2 per yr was ad equate for growth of dianthus during the second growth season In 2008 2009, shoot dry mass for increased with N fertilization rates. However, fertilization at rates exceeding 4 lb/1000 ft 2 per yr did not produce significantly mo re biomass than the higher N fertilizer rates (Figure 3 3). In 2009 2010, plants fertilized at rates exceeding 6 lb/1000 ft 2 per yr did not produce significantly more biomass (Figure 3 4). Plant quality and chlorophyll content In 2008 2009, quality ratings of were satisfactory or above for 95% of plants fertilized at the 3 highest N rates at 6 WAP However, plants fertiliz ed with N at

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86 the 12 lb/1000 ft 2 per yr rate received the highest percentages of quality ratings 4 and 5 (above av erage and outstanding) (Table 3 4). At 12 WAP the quality ratings for plants receiving N at the highest treatment rate (12 lb/1000 ft 2 per yr) began to decline which indicate d that higher fertilizer rates accelerated the development of the plant, push ing it through its life cycle at a faster rate. The fertilization rate of 6 lb/1000 ft 2 per yr produced plants with the best quality ratings at 12 WAP (Table 3 4). At 18 WAP q uality ratings for plants receiving 6 lb/1000 ft 2 per yr N were higher than plan ts receiving N at the other treatment rate s ; no plants receiving N at the 6 lb/1000 ft2 per year rate were below satisfactory (<3) during any of the measure ment periods (Table 3 4). In 2009 2010, quality ratings for d ianthus at 6 WAP show ed only small diff erences due to N fertilizer treatments (Table 3 4) All treatments resulted in satisfactory or above quality ratings for 90% of plants However, 100% of the plants fertilized with 2 lb/1000 ft 2 per yr N received satisfactory or above quality ratings At 12 WAP the quality ratings increased with increasing fertilization rate with the 12 lb/1000 ft 2 per yr N rate producing plants with the highest quality ratings At 18 WAP quality ratings of plants receiving 6 and 12 lb/1000 ft 2 per yr were above average Overall, we suggest that fertilization with 6 lb/1000 ft 2 per yr N produce d high quality (Table 3 4). In 2008 2009, SPAD measurements increased with increasing N fertilization rate (Figure 3 5) However, the 4 lb/1000 ft 2 per yr N rate did not produce plants with significantly different higher SPAD measurements than the 6 or 12 lb/1000 ft 2 per yr rates at 6 or 18 WAP (Figure 3 5 a and c) At 12 WAP plants receiving 6 lb/1000 ft 2 per yr N did not have SPAD measurement that were si gnificantly different from any other N rate (Figure 3 5 b ).

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87 In 2009 2010, SPAD measurement increased with increasing N fertilization rates (Figure 3 6) However, at 6 WAP unfertilized plants ( 0 lb/1000 ft 2 per yr ) had significantly lower SPAD measurements than plants receiving N at the 2 and 12 lb/1000 ft 2 per yr rates (Figure 3 6 a ). At 12 WAP unfertilized plants had significantly lower SPAD measurements compared with plants receiving all other N fertilizer rates; but SPAD was not different among plants fe rtilized at any of the other rates (Figure 3 6 b ). At 18 WAP fertilization with N at rates exceeding 4 lb/1000 ft 2 per yr did not produce plants with statistically higher SPAD measurements (Figure 3 6 c ). Therefore, we suggested that fertilization of with 4 lb/1000 ft 2 per yr. Flower cover index Flower cover index results for indicated no significant differences at 0 or 6 WAP du e to N fertilizer rate (Table 3 5) At 12 WAP flower cover age ( percent of ca nopy) increased with increasing N rate with t he 12 lb/1000 ft 2 per yr N rate producing plants with the highest percentage of flower cover followed by 4 and 6 lb/1000 ft 2 per yr and 6 lb/1000 ft 2 (Table 3 5) The low mean flower cover percentages reported for 12 WAP were due to freezing temperatures during th e growing season that resulted in flower loss. At 18 WAP the flower coverage increased with increasing N rate, but fertilization at rates exceeding 6 lb/1000 ft 2 per yr did not result in a significant increase in flower cover Foliar nutrient concentration analysis During the 2008 2009 season, t issue levels of N showed strong treatment effects with N tissue concentration significantly increasing with N treatment (Figure 3 7) Plants receiving N at the 12 lb/1000 ft 2 per yr rate had significantly higher TKN concentration s than plants fertilized at lower rates (Figur e 3 7). Tissue levels of Fe, Mn Zn, Ca, Mg, and K were relatively constant with no significant differences in rel ation to treatment (Data

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88 not shown) The P levels in plants receiving no additional N were significantly higher than those receiving at the 4 or 12 lb/1000 ft 2 per yr rates (Data not shown) During the 2009 2010 season, leaf t iss ue concentrations showed a strong treatment effect with N tissue concentration increasing significantly with increasing N treatment (Figure 3 8). Tissue l evels of Mn, Zn, Ca, Mg, and K were relatively constant (Table 3 7) with no significant differences i n relation to treatment (Data not shown) Tissue levels of Fe decreased with increasing N rate (Data not shown), while P concentrations in plant tissue receiving no additional N were significantly higher than those receiving N fertilization (Data not shown ) The nutrient tissue concentrations in both seasons differed from suggested nutrient concentrations for dianthus chinensis under greenhouse production conditions provided by Mills and Jones (1996) (Table 3.7) Th ese differences could be due to the fact that the plants in this study were older than the plants analy zed by Mills and Jones (Mills and Jones, 1996) when they wer e sampled (more suberized etc.) or because the growing environment in our study was not as well controlled. Whereas the plants produced in the greenhouse were young and were grown under optimal conditions. The tissue nutrient N, K, Mg, and Mn concentratio ns in our study were considered low when compared to tissue concentrations reported by Kessler (2007) for dianthus grown under greenhouse conditions In contrast, P and Ca concentrations were within the reported range and Fe concentrations from the second year w ere considered high ; Zn concentratations ranged from low to high ( Tables 3 6 and 3 7 ) Overall nitrogen requirement for dianthus Based on p lant response to N fertilizer rates in both seasons, we suggested a n N fertilization requirement of 6 lb/1000 ft 2 per d ianthus. What was d ianthus particularly during the second year of the

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89 study was that they were prone to Lepidoptera damage. Also, during the sec ond year of the study several plants were killed by rhizoctonia fungus. The unusually warm temperatures that existed at the beginning of that cool season may have aided the spread of this fungus. From 4 Oct 2009 through 10 Nov. 2009 average temperatures ranged from 59.9F 83.1F. The spread of the fungus was stopped by means of the application of fung icides on 16 Dec. 2009 (Table 3 1). Also between 6 and 12 WAP during the second year of the study (2 Jan. 2010 13 Jan. 2010) there were unusually cold temperatures that caused flower loss. The a verage temperature ranged from 33.6F 47F with a minimum temperature of 24F. The flowers returned shortly after the temperatures increased within a normal range again. Antirrhinum majus ) Plant growth and shoot dry mass In 2008 2009, the GI of snapdragon increased with N fertilization rates (Figure 3 9) At 6 and 12 WAP plants fertilized at the 12 lb/1000 ft 2 per yr N rate had significantly higher GI than plants fertilized at all other N rates (Figure 3 9 a and b ). At 18 WAP fertilization of snapdragons with more than 4 lb/1000 ft 2 per yr N did not significantly increase GI (Figure 3 9 c ). In 2009 2010, GI of snapdragon generally increased with increasing N fertilization rate (Figure 3 10) At 6 WAP the highest GI was achieved when plants were fertilized with 6 or 12 lb/1000 ft 2 per yr N (Figure 3 10 a ). At 12 WAP the 12 lb/1000 ft 2 per yr N rate produced plants that were significantly larger than all other N treatment rate s (Figure 3 10 b ). At 18 WAP fertilization at rates exceeding 6 lb/1000 ft 2 per yr did not significantly increase GI (Figure 3 10 c ). Therefore, we suggest the fertilization rate of 6 lb/1000 ft 2 per yr for GI response In 2008 2009, shoot dry mass for s napdragons increased with increasing N fertilization rates (Figure 3 11) However, shoot dry mass of plants receiving 4 lb/1000 ft 2 per yr was not

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90 significantly different from those receiving the higher N rates (Figure 3 11). In 2009 2010, shoot dry mass increased with N rate with the 12 lb/1000 ft 2 per yr N rate produc ing the largest plants (Figure 3 12). Plant quality and chlorophyll content In 2008 2009, quality ratings appeared to increase with N through 12 WAP (Table 3 4) The three highest treatments (4, 6, and 12 lb/100 0 ft 2 per yr) generally produced plants with higher quality ratings than the lowest N treatments. By 18 WAP, the quality of plants receiving the two highest treatments declined and the 4 lb/1000 ft 2 per yr rate resulted in the fewest plants with below the satisfactory (<3) quality ratings Overall, 6 lb/1000 ft 2 per yr was most favorable (Table 3 4). In 2009 2010, quality ratings appeared to increase with N through 12 WAP (Table 3 4) At 6 WAP, all treatments resulted in 90% of the plants with satisfactory o r above quality ratings (Table 3 4). At 12 WAP, the 12 lb/1000 ft 2 per yr N rate resulted in plants with the highest quality ratings (Table 3 4). By 18 WAP the 12 lb/1000 ft 2 per yr N rate produced the highest median quality ratings. However, the 4 and 6 lb/1000 ft 2 per yr N rates both resulted in 100% of plants being rated as satisfactory or above (Table 3 4). Overall, the fertilization rate of 12 lb/1000 ft 2 per yr produced the highest quality snapdragon for the second year of the study although the fert ilization rate s of 4 and 6 lb/1000 ft 2 per yr produced a majority of satisfactory level plants throughout the growing season. During the 2008 2009 growing season, SPAD readings increased with N fertilization rates (Figure 3 13) At 6 WAP the 4 6, and 12 lb/1000 ft 2 per yr N rates produced plants with SPAD measurements that were not significantly different from one another (Figure 3 13). At 12 WAP there wa s no significant difference in SPAD between plants receiving N fertilizer and these plants had higher SPAD measurements than unfertilized plants (Figure 3 13). At 18 WAP there

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91 was no significant difference in SPAD measurements between the 6 and 12 lb/1000 ft 2 per yr N rates (Figure 3 13). During the 2009 2010 growing season, SPAD readings also increased with increasing N fertilization rates (Figure 3 14) At 6 WAP there were no significant differences in SPAD between the 4 6, or 12 lb/1000 ft 2 per yr N rates (Figure 3 14). At 12 WAP, the 6 and 12 lb/1000 ft 2 per yr N fertilizer rates resulted in plants with the high est SPAD measurements (Figure 3 14). At 18 WAP there were no significant differences in SPAD between the 4 6, or 12 lb/1000 ft 2 per yr N fertilizer rates (Figure 3 14). In the second season, a fertilization rate of 4 lb/1000 ft 2 per yr pro d uced SPAD readings that were comparable to plants receiving N at higher fertilization rates. Flower cover index Flower cover index results for indicated no significant N fertilizer effect at 6 WAP (Table 3 5). At 12 WAP there w e re significant differences in flower cover due to N rate The 6 and 12 lb/1000 ft 2 per yr N rates produced plants with the highest percentages of flower cover followed by the 4 lb/1000 ft 2 per yr which was not significantly different from the 6 lb/1000 ft 2 per yr rate (Table 3 5). At 18 WAP there were no significant differences in flower cover between the three highest N rates (Table 3 5). Foliar nutrient concentration analysis In 2008 2009 leaf t issue concentrations of N in s napdragon showed strong tr eatment effects with N tissue concentration significantly increasing with increasing N rates Plants receiving N fertilization at the 12 lb/1000 ft 2 per yr rate had a significantly hig her TKN concentration (Figure 3 15). Tis sue concentrations of Mn, P, Ca, and K were relatively constant (Table 3 8) with no significant differences in relation to treatment (Data not shown) Tissue concentrations of Mg increased with increasing N rate, while tissue levels of Zn and Fe

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92 decreased as N rate increased (Data not sh own) Tissue results from this study were compared to Creel and Kessler (2007) results (Table 3 8 ) In 2009 2010 leaf t issue concentration of N in showed strong treatment effects with N tissue concentration significantly increasing as N rates increased (Figure 3 16) Tissue concentrations of Mn, P, and Ca were relatively constant (Table 3 9) with no significant differences due to N fertilizer rate (Data not shown). Tissue concentrations of Mg increased with increasing N while tissue concentrations of Zn, K and Fe decreased with increasing N. Tissue results from this study were compared to Kessler results (Creel and Kessler, 2007) (Table 3 9) Overall nitrogen requirement of snapdragon B ased o n th e first and second year data we suggest a fertilization r equirement of 6 lb/1000 ft 2 per yr resulted in aesthetically pleasing when grown in the landscape under the conditions of this study. The growth index for both years was not increased when snapdragons were fert ilized at a rate exceeding 6 lb/1000 ft 2 per yr. However, excellent quality plants were produced in year two when N was applied at 12 lb/1000 ft 2 per yr. Both the first and second year data suggests that the fertilization rate of 4 lb/1000 ft 2 per yr was a dequate for SPAD measurements and that the fertilization rate of 4 lb/1000 ft 2 per yr was best for flower cover during the second year of the study. Therefore we suggest that the N requirements for s napdragon were 6 lb/1000 ft 2 per yr under the conditions of this study. In 2009 2010, many of the snapdragons were infected with Botrytis causing some flower loss in the early weeks of the experiment. As soon as symptoms were identified they were treated with a fungicid e (Table 3 1). This infection was probably due to the unusually warm temperatures that existed at the beginning of that cool season. From 4 Oct. 2009

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93 10 Nov. 2009 average temperatures ranged from 59.9F 83.1F. Between 6 and 12 WAP ( 2 Jan. 2010 13 Ja n. 2010) there were unusually cold temperatures that caused flower loss. The average temperature ranged during this time ranged from 33.6F 47F with a minimum temperature of 24F. The flowers returned shortly after the temperatures increased within a normal range. Viola wittrockiana ) Plant growth and shoot dry mass In 2008 2009, GI for p ansies increased with increasing N fertilization rates (Figure 3 17) However, the three highest N fertilization rates did not result in significantly different GI at 6, 12 or 18 WAP. Therefore, we suggest that the lowest fertilization rate 4 lb/1000 ft 2 per yr was appropriate for growth (Figures 3 17). In 2009 2010, GI of p ansies at 0 and 6 WAP show ed no effects due to N fertilizer rate (Figure 3 18 a ). At 12 WAP the GI of plants receiving 4 6, and 12 lb/1000 ft 2 per yr wa s not st atistically different (Figure 3 18 b ). At 18 WAP the re were no significant differences in GI for plants receiving 6 or 12 l b/1000 ft 2 per yr (Figure 3 18 c ). The treatment of 6 lb/1000 ft 2 per yr was suggested for growth of p ansies in the second year of the study. In 2008 2009, shoot dry mass for p ansies increased with increasing N fertilization rates. Howev er, fertilization at rate s exceeding 4 lb/1000 ft 2 per yr did not produce significantly higher dry mass (Figures 3 19 and 3 20). Plant quality and chlorophyll content In 2008 2009, quality ratings at 6 WAP indicate that median quality of plants receiving a ll N fertilization rates was 3. A t 12 plants receiving 4, 6 and 12 lb/1000 ft 2 per yr had a median quality of 3. However, a t 18 WAP plants receiving a fertilization rate of 4 lb/1000 ft 2 per yr received the highest median quality ratings (Figures 3 4)

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94 In 2009 2010, quality ratings at 6 WAP indicate that median quality of plants receiving all N fertilization rates was 3 At 12 WAP plants receiving a n N rate of 2, 4 6, and 12 lb/1000 ft 2 per yr received a median quality rating of At 18 WAP the treatment s of 6 and 12 lb/1000 ft 2 per yr had median quality ratings of 4 which were higher than plants reviving all other treatments ( Table 3 4). In 2008 2009, SPAD measurements increased with increasing N (Figure 3 21) However, the three highest N rates did not pr oduce plants with significantly different SPAD measurements at 6, 12 or 18 WAP. Therefore, we suggest the lowest fertilization rate of 4 lb/1000 ft 2 per yr (Figure 3 21). In 2008 2009, SPAD measurements increased with increasing N (Figure 3 22) However, the three highest N rates did not produce significantly different SPAD measurements at 6 or 12 WAP. At 18 WAP SPAD measurements increase d with N and plants receiving an N rate of 12 lb/1000 ft 2 per yr had significantly higher SPAD measurements. Therefore the fertilization treatment of 6 lb/1000 ft 2 per yr was deemed adequate for SPAD measurements (Figures 3 22). Flower cover index Flower cover index results for p ansy indicated that there w as no N fertilizer treatment effect at 6 WAP. At 12 WAP there wer e significant N treatment effects were unfertilized plants had significantly lower flower cover index than the other four treatments (Table 3 5) At 18 WAP there were no significant differences among treatments due to N fertilizer rate (Table 3 5). Folia r nutrient concentration analysis In 2008 2009 leaf t issue levels of N in pansies showed strong treatment effect with N tissue concentration significantly increasing with increasing N treatment. Plants receiving the fertilization treatment of 12 lb/1000 ft 2 per yr had a significantly higher TKN concentration than plants fertilized at lower rates (Figure 3 23). Tissue concentrations of Fe, Mn, Zn, P, Ca, and K

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95 were relatively constant (Table 3 10) with no significant differences in relation to treatment (D ata not shown) Tissue concentrations of Mg increased with increasing N fertilizer rate (Data not shown) Pansy nutrient concentrations were all low to within the range provided by Mills and Jones (1996) In 2009 2010 leaf t issue concentrations of N in pansies showed strong treatment effects with N tissue concentr ation significantly increasing with increasing N rate Plants receiving the fertilization treatment of 12 lb/1000 ft 2 per yr had a significantly higher TKN concentration than pansies fertilized at lower rates (Figure 3 24). Tissue concentrations of Mn, Zn, P, Ca, and K were relatively constant (Table 3 11), with no significant differences in relation to treatment (Data not shown). Tissue concentrations of Mg increased with increasing N rate, while tissue concentrations of Fe decreased with increasing N rate (Data not shown) Pansy nutrient concentrations were within the range s provided by Mills and Jones (1996) for most elements Overall nitrogen requirement of pan sy Based on d ata from both study year s, we suggest ed the fertilization rate of 6 lb/1000 ft 2 pe r yr was adequate for growth index and SPAD measurements, while 4 lb/1000 ft 2 per yr was adequate for quality. Therefore a fertilization rate of 6 lb/1000 ft 2 per yr was deemed adequate for p ansies when grown in the landscape under the conditions of this study

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96 Figure 3 1. Growth indices of d ianthus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) b c a B A A A B D A A B C D A A B C Annual N Fertilizer Rate (per 1000 ft 2 )

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97 Figure 3 2. Growth indices of d ianthus ( ) grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in U SDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) c b a A A A A A C A AB BC C C A A B B Annual N Fertilizer Rate (per 1000 ft 2 )

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98 Figure 3 3. Dry shoot mass of d iant hus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates at 18 weeks in USDA hardiness zone 9b. P bars indicate t he 95% confidence interval. A A A B C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean Dry Shoot (g)

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99 Figure 3 4. Dry shoot mass of d ianthus ( ) grown in raised landscape beds (2009) and fertilized with at five N rates at 18 weeks in USDA hardiness zone 9b. Mean separation by Tuke P bars indica te the 95% confidence interval. A A B B C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean Dry Shoot (g)

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100 Figure 3 5 SPAD measurements of d ianthus ( ) grown in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks i n USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean SPAD Measurement c b a A A A B C A AB B B C A A AB B C Annual N Fertilizer Rate (per 1000 ft 2 )

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101 Figure 3 6 SPA D m easurements of d ianthus ( ) grown in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. Mean separatio P bars indicate the 95% confidence interval. Mean SPAD measurements c a b A AB AB A B A A A A B A A AB B C Annual N Fertilizer Rate (per 1000 ft 2 )

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102 Figure 3 7 Tissue concentrat ions of total Kjeldahl N (TKN) for d ianthus ( Dianthus chinensis ) grown in raised landscape beds (2008) and fertilized with at five N rates collected at 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A B B C D Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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103 Figure 3 8 Tissue concentra tions of total Kjeldahl N (TKN) for d ia nthus ( Dianthus chinensis ) grown in raised landscape beds (2009) and fertilized with at five N rates collected at 18 weeks in USDA hardiness zone 9b. P bar s indicate the 95% confidence interval. A B C C D Mean TKN Percent Annual N Fertilizer Rate (per 1000 ft 2 )

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104 Figure 3 9 Growth indices of sna pdragon ( Antirrhinum majus raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) a b c A B B BC C A B B C D A A A B C Annual N Fertilizer Rate ( per 1000 ft 2 )

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105 Figure 3 10 Growth indices of sna pdragon ( Antirrhinum majus raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in US DA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. b c a Mean Growth Index (cm 3 ) A AB C BC C A B C D D A A B C D Annual N Fertilizer Rate (per 1000 ft 2 )

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1 06 Figure 3 11. Shoot dry mass of s napd ragon ( Antirrhinum majus raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. P bars indicate t he 95% confidence interval. A A A B C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean Shoot Dry Mass (g)

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107 Figure 3 12. Shoot dry mass of s napdragon ( Antirrhinum majus raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. Mean separation by Tuk P bars indicate the 95% confidence interval. A B C D E Mean Shoot Dry Mass (g ) Annual N Fertilizer Rate (per 1000 ft 2 )

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108 Figure 3 1 3 SPAD measurements of s napdragon ( Antirrhinum majus in raised landscape beds (2008) and fertilized with at five N rates for 18 weeks i n USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. c a b Mean SPAD Measurements A AB AB BC C A A A A B A AB B B C Annual N Fertilizer Rate (per 1000 ft 2 )

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109 Figure 3 14 SP AD measurements of s napdragon ( Antirrhinum majus in raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. Mean separatio P bars indicate the 95% confidence interval. c a b Mean SPAD Measurements A A A AB B A AB B C D A A AB B C Annual N Fertilizer Rate (per 1000 ft 2 )

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110 Figure 3 15 Tissue concentrations of total Kjeldahl N (TKN) of s napdragon ( Antirrhinum majus N rates collected at 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A B B B C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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111 Figure 3 16 Tissue concentrations of total Kjeldahl N (TKN) of s nap dragon ( Antirrhinum majus N rates collected at 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A B B C D Mean TKN Percent Annual N Fertilizer Rate (per 1000 ft 2 )

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112 Figure 3 17 Growth indices of p ansy ( Viola wittrockiana landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9 b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean Growth Index (cm 3 ) c a b A B AB B B A A A B B A A A B B Annual N Fertilizer Rate (per 1000 ft 2 )

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113 Figure 3 18 Growth indices of p ansy ( Viola wittrockiana landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. a b c Mean Growth Index (cm 3 ) A A A A A A AB AB BC C A B A BC CD D Annual N Fertilizer Rate (per 1000 ft 2 )

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114 Figure 3 19. Shoot dry mass of p an sy ( Viola wittrockiana landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A A A B C Annual N Fertilizer Rate (per 100 0 ft 2 ) Mean Dry Shoot (g)

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115 Figure 3 20. Shoot dry mass of p ansy ( Viola wittrockiana landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b. Mean separation by Tu P bars indicate the 95% confidence interval. A A A B B Annual N Fertilizer Rate (per 1000 ft 2 ) Mean Dry Shoot (g)

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116 Figure 3 21 SPAD measurements of p ansy ( Viola wittrockiana raised landscape beds (2008) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. P bars indicate the 95% confidence interval. Mean SPAD Measurements c b a A A A B B A A A B C A A A B C Annual N Fertilizer Rate (per 1000 ft 2 )

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117 Figure 3 22 SPAD measurements of p ansy ( Viola wittrockiana raised landscape beds (2009) and fertilized with at five N rates for 18 weeks in USDA hardiness zone 9b at a) 6 weeks after planting (WAP), b) 12 WAP and c) 18 WAP. Mean separat P bars indicate the 95% confidence interval. Mean SPAD Measurements a c b A A A AB B A A A B C A B B C D Annual N Fertilizer Rate (per 1000 ft 2 )

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118 Figure 3 23 Tissue concentrations of total Kjeldahl N (TKN) for p ansy ( Viola wittrockiana N rates collected at 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A AB B B C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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119 Figure 3 24 Tissue concentrations of total Kjeldahl N (TKN) for p ans y ( Viola wittrockiana N rates collected at 18 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval A B B C D Mean TKN Percent Annual N Fertilizer Rate (per 1000 ft 2 )

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120 Table 3 1. Pesticides applied to cool season annual species grown in raised beds in USDA hardiness zone 9b between 2009 2010. Date Pesticide Active i ngredient Plant t reated Target p est 2 Oct. 2009 Banrot Thiophanate methyl, Etridiazole Dianthus, Snapdragon, Pansy Phythopthera 7 Oct. 2009 Safari Dianthus, Snapdragon, Pansy Whitefly 22 Oct. 2009 Banrot Thiophanate methyl, Etridiazole Dianthus, Snapdragon, Pansy Phythopthera 22 Oct. 2009 Xentari Bacillus t huringiens is Dianthus, Snapdragon, Pansy Lepidoptera 5 Nov. 2009 Banrot Thiophanate methyl, Etridiazole Dianthus, Snapdragon, Pansy Phythopthera/Crown r ot 8 Dec. 2009 Cleary Thiophanate methyl Pansy Crown r ot 8 Dec. 2009 Ridomil Gold M ancozeb Pansy Crown r ot 16 Dec. 2009 Chipco 26019 Iprodione Dianthus, Snapdragon, Pansy Rhyzoctonia 16 Dec. 2009 Banrot Thiophanate methyl, Etridiazole Dianthus, Snapdragon, Pansy Rhyzoctonia 17 Dec. 2009 Conserve Spinosad Dianthus, Snapdragon, Pansy Lepidoptera 17 Dec. 2009 Clea ry Thiophanate methyl Dianthus, Snapdragon, Pansy Botritis

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121 Table 3 2. Total irrigation and rainfall volumes applied to cool season annual plant species grown in raised beds in USDA hardiness zone 9b between November 2008 and March 2009. Week Irrigation (in/week) Rainfall total z (in/week) Irrigation + rainfall (in) Cumulative rainfall (in) 1 0.71 0.00 0.71 0.71 2 0.71 0.00 0.71 1.42 3 0.71 1.14 1.85 3.26 4 0.71 0.14 0.89 4.11 5 0.71 1.19 1.90 6.01 6 0.71 0.03 0.74 6.75 7 0.71 0.00 0.71 7.46 8 0.7 1 0.00 0.71 8.16 9 0.71 0.01 0.72 8.88 10 0.71 0.39 1.10 9.98 11 0.71 0.22 0.93 10.9 12 0.71 0.85 1.56 12.5 13 0.71 0.44 1.15 13.6 14 0.71 0.00 0.71 14.3 15 0.71 0.04 0.75 15.1 16 0.71 0.18 0.89 16.0 17 0.71 0.00 0.71 16.7 18 0.71 0.01 0.72 17.4 z Rainfall data collected at 2 m from the Florida Automated Weather Network station located approximately 805 m from the planting s ite (University of Florida, 2010)

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122 Table 3 3. Total irrigation and rainfall vo lumes applied to cool season annual plant species grown in raised beds in USDA hardiness zone 9b between November 2009 and March 2010. Week Irrigation (in/week) Rainfall total z (in/week) Irrigation + rainfall (in) Cumulative rainfall (in) 1 0.71 0.00 0.71 0.71 2 0.71 1.45 2.16 2.87 3 0.71 2.20 2.91 5.77 4 0.71 0.07 0.78 6.55 5 0.71 0.13 0.84 7.39 6 0.71 0.08 0.79 8.18 7 0.71 0.28 0.99 9.17 8 0.71 0.18 0.89 10.1 9 0.71 1.00 1.71 11.8 10 0.71 0.77 1.48 13.2 11 0.71 0.95 1.66 14.9 12 0.71 0.90 1.61 16.5 13 0.71 0.75 1.46 18.0 14 0.71 0.00 0.71 18.7 15 0.71 0.58 1.29 20.0 16 0.71 0.20 0.91 20.9 17 0.71 2.20 2.91 23.8 z Rainfall data collected at 2 m from the Florida Automated Weather Network station located approx imately 805 m from the planting s ite (University of Florida, 2010)

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123 Table 3 4 Median visual quality ratings for Dianthus chinensis 'Telstar crimson', Viola x wittrockiana 'Delta pure violet' and Antirrhinum majus 'Montego yellow' fertilize d at five N rates grown in two seasons (2008 and 2009) in U.S. Department of Agriculture hardiness zone 9b. Annual N fertilizer r ate (lb/1000ft 2 ) Plant quality rating Season 1 Season 2 0 WAP z 6 WAP 12 WAP 18 WAP 0 WAP 6 WAP 12 WAP 18 WAP Dianth us chinensis 'Telstar crimson' 0 5 3 1 1 5 4 2 2 2 5 3 3 3 5 4 2.5 3 4 5 3 3 4 5 4 3 3 6 5 4 4 3.5 5 4 3 4 12 5 4 4 3 5 4 4 4 Viola x wittrockiana 'Delta pure violet' 0 5 3 2 1 5 3 2 2 2 5 3 2 2 5 3 3 3 4 5 3 3 4 5 3 3 3 6 5 3 3 3.5 5 3 3 4 12 5 3 3 3 5 3 3 4 Antirrhinum majus 'Montego yellow' 0 5 2 1 1 5 3 2 2 2 5 2 2 3 5 3 2 3 4 5. 3 3 4 5 3 3 3 6 5 3 4 3 5 3 3 4 12 5 4 4 3 5 4 4 4.5 Z WAP = week after planting

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124 Table 3 5 Flower cover i ndex for Dianthus chinensis 'T elstar C rimson', Viola wittrockiana 'Delta Pure V iolet' and Antirrhinum majus 'Montego Yellow' fertilized at five N rates (0, 2, 4, 6, and 12 lb N/1000 ft 2 per yr ) grown in two seasons (2008 and 2009) in U.S. Department of Agriculture hardiness zone 9b. Annual N fertilizer r ate (lb/1000ft 2 ) Flower cover index z 6 WAP y 12 WAP 18 WAP Antirrhinum majus 'Montego Y ellow' (snapdragon) 0 20.6 a 29.0 d 14.6 c 2 14.8 a 34.1 cd 30.3 b 4 13.0 a 38.7 bc 39.0 ab 6 17.1 a 44.5 ab 40.2 a 12 21.2 a 47.5 a 41.5 a Dianthus chinensis 'Telstar C rimson' (dianthus) 0 51.2 a 7.00 d 24.0 d 2 49.6 a 16.9 c 39.4 c 4 47.5 a 23.0 b 47.1 bc 6 50.3 a 22.8 b 59.2 a 12 36.6 a 29.6 a 56.6 ab Viola wittrockiana 'Delta Pure V iolet' (pansy) 0 35.6 a 35.4 b 58.6 a 2 36.1 a 42.9 ab 63.9 a 4 34.2 a 44.8 a 62.6 a 6 32.5 a 52.2 a 58.7 a 12 25.2 a 51.0 a 63.2 a z Flower cover index = Flower/ (Flower + Canopy)*100 y WAP = week after planting x t difference

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125 Table 3 6 Leaf tissue nutrient analysis for Dianthus chinensis grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 compared with published values. Element Dianthus chinensis published analysis z range N % 4.84 1.47 3.57 P % 0.48 0.37 0.44 K % 3.70 2.03 3.18 Ca % 1.68 1.76 2.07 Mg % 1.05 0.49 0.74 Fe mg kg 1 81.0 68.7 79.8 Mn mg kg 1 442 40.2 64.5 Zn mg kg 1 75.0 17.8 41.1 z Values reported are for Dianthus chinensis in a greenhouse production setting (Mills and Jones, 1996)

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126 T able 3 7 Leaf tissue nutrient analysis for Dianthus chinensis grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2009 2010 compared with publish ed values. Element Dianthus chinensis published analysis z range N % 4.84 1.31 3.23 P % 0.48 0.3 0.91 K % 3.70 0.99 3.15 Ca % 1.68 1.32 3.31 Mg % 1.05 0.62 1.01 Fe mg kg 1 81.0 121 531 Mn mg kg 1 442 65.3 206 Zn mg kg 1 75.0 39.5 218 z Values reported are for Dianthus chinensis in a greenhouse production setting (Mills and Jones, 1996)

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127 Table 3 8 Leaf tissue nutrient analysis for Antirrhinum majus grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 compared with published values. Element Antirrhinum majus published analysis z Snapdragon 'Montego Yellow' range N % 3.80 5.00 1.39 2.96 P % 0.30 0.50 0.19 0.23 K % 2.00 3.00 1.04 1.44 Ca % 1.00 1.50 2.04 2.23 Mg % 0.84 0.64 0.97 Fe mg kg 1 75.0 68.9 115 Mn mg kg 1 139.0 17.98 35.0 Zn mg kg 1 56.0 13.9 33.8 z Values reported are for Antirrhinum majus in a greenhouse production setting (Creel and Kessler, 2007)

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128 Table 3 9 Leaf tissue nutrient analysis for Antirrhinum majus grown in raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2009 2010 compared with published values. Element Antirrhinum majus published analysis z Snapdragon 'Montego Yellow' range N % 3.80 5.00 1.51 3.02 P % 0.30 0.50 0.21 0.46 K % 2.00 3.00 0.72 2.55 Ca % 1.00 1.50 2.10 3.28 Mg % 0.84 0.62 1.33 Fe mg kg 1 75.0 122 419 Mn mg kg 1 139 26.7 112 Zn mg kg 1 56.0 26.7 63.3 z Values reported are for Antirrhinum majus in a greenhouse p roduction setting (Creel and Kessler, 2007)

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129 Table 3 10 Leaf tissue nutrient analysis for Viola wittrockiana raised beds in USDA hardiness zone 9b and fertilized at five N rates in 2008 2009 compared with published values. Ele ment Viola wittrockiana published analysis z range N % 3.44 4.20 1.54 3.63 P % 0.37 0.64 0.19 0.26 K % 2.39 2.92 1.43 2.66 Ca % 0.90 1.16 0.13 1.45 Mg % 0.36 0.49 0.42 0.69 Fe mg kg 1 80.0 398 63. 9 70.5 Mn mg kg 1 41.0 203 72.0 107 Zn mg kg 1 44.0 137 25.5 42.2 z Values reported are for Viola wittrockiana in a greenhouse production setting (Mills and Jones, 1996)

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130 Table 3 11 Leaf tissue nutrient analysis for Viola wittrockiana raised beds in USDA hardiness z one 9b and fertilized at five N rates in 2009 2010 compared with published values. Element Viola wittrockiana published analysis z range N % 3.44 4.20 1.20 3.38 P % 0.37 0.64 0.25 0.54 K % 2.39 2.92 0.61 2.51 Ca % 0.90 1.16 0.88 2.75 Mg % 0.36 0.49 0.39 1.04 Fe mg kg 1 80.0 398 123 392 Mn mg kg 1 41.0 203 37.5 208 Zn mg kg 1 44.0 137 32.5 142 z Values reported are for Viola wittrockiana in a greenhouse production setting (Mills and Jones, 1996)

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131 CHAPTER 4 DETERMINATION OF NITROGEN REQUIR E M ENTS FOR FIVE SPECIES OF HERBACEOUS PERENNIALS Introduction The basis for current nitrogen (N) fertilizer recommendations for landscape grown ornamental plants in Florida is unclear. Much of the research that exists was performed on trees and shrubs, whic h may have different fertilization requirements than perennials, annuals, vines and groundcovers. Therefore, the current fertilizer recommendations need to be validated for additional plant types, such as annual bedding plants, that are grown in the landsc ape. Knowledge of specific fertilizer requirements will allow plants to be zoned within the landscape based on their fertilizer requirements. Zoning based on fertilizer requirements will result in more efficient fertilizer application, thus reducing nutrie nt losses to the environment. The objective of this study was to determine N requirements of Bush Daisy ( Gamolepis chrysanthemoides) (Lantana x hybrid) ( Salvia longispicata x farinacea) Evergreen G ian Liriope muscari) Caladium bicolor) when grown in raised beds containing subso il fill material. We achieved this objective by determining plant response (e.g., growth, quality, flower cover) to N fertilizer applie d at five different rates when all other plant nutrients were available at concentrations that would not limit growth. Materials and Methods Plant Material Five herbaceous perennials, bush daisy ( Gamolepis chrysanthemoides ) lantana ( Lantana hy brid ) Salvia longispicata farinacea ) Evergreen Liriope muscari ) Caladium bicolor ) were selected for evaluation across a range of N fertilization regimes. Bush daisy, lantana, and s alvia

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132 were received as 144 sized plugs from Riverview Flower Farm (Riverview, FL), and caladium tubers were received from Bates Sons and Daughters (Lake Placid, FL). Liriope plants were received in 1 gallon pots from J & R Nursery (Dover, FL) on 21 May 200 8. B ush daisy, lantana, and salvia were potted into 4 in azalea pots containing Verlite Vergo Mix A potting mix (Verlite Company, Tampa, FL ) on 19 May 2008. The plants were grown in a greenhouse and were fertilized biweekly with 20N 4.4P 16.6K (Peat Lite S pecial; The Scotts 1 Plants were treated with imidicloprid (Marathon 60 WP; OHP, Inc., Mainland, PA) on 20 May 2008 to control white flies. On 30 May 2008, plants were moved from the greenhouse to an outsi de nursery to be hardened off, at which time the fertilizer was changed to a 21N 3.0P 5.8K (Acid Special; The Scotts Company, 1 The N fertilizer rate was 1 N two times per STEM; The Scotts Company, Marysville, OH) containing S, B, Cu, Fe, Mn, Mo, and Zn was also applied weekly at the label rate (0.5 lb/100 gal) until perennials were planted into the landscape plots. Calad ium tubers were planted directly into the landscape. All plants were planted into the landscape beds in a randomized complete block design on 1 July 2008. Experimental Design Fifteen raised beds (3.08 m 12.19 m 0.15 m) were established at the Universit y of Florida Institute of Food and Agricultural Sciences (UF IFAS) Gulf Coast Research and Education Center in Wimauma, FL. The raised beds were filled with a St. Johns fine sand (USDA NRCS, 2004) collected from a depth of 21.34 m below the soil surface. This soil was representative of soil commonly used in construction areas of central Florida (USDA NRCS, 2004) The soil pH was adjusted using dolomitic lime (Sunniland lawn and garden lime, Sanford, FL) prior to planting an d again on 4 Aug. 2009 (Table 2 1). Thirty six

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133 annual plants were planted in cl usters within each raised landscape Each plant cluster contained three plants of the same species forming a triangle with individual plants spaced 0.31 m apart, for a total of 4 clusters per species per plot. Nitrogen rates were based on the Florida Frie fertilizer recommendations for landscape plants (Florida Department of Environmental Protection, 2002) A polymer coated ammonium sulfate fertilizer (21N 0P 0K 24S, Honeywell Nylon, LLC, Seffner, FL) was applied from 30 June 2008 to 17 A ug. 2009 and a polymer coated urea (42N 0P 0K, Lakeland, FL) was applied to the end of the study (May 2010) at the following N rates: 0, 2, 4, 6 and 12 lb/1000 ft 2 per yr 2 per yr). Beds were not mulched to minimize outside N contributions. Other nutrients were applied at the same rate to all plots based on soil test and plant requirements based on UF IFAS recommendations (Kidder et al., 2009) Potassium (K) (0N 0P 41.5K, Great Salt Lake Minerals Corp., Overland Park, KS) was applied every four months at an N rate of xx lb/10 00 ft 2 per yr ( 22.5 gm 2 per yr ) (Kidder et al., 2009) A micronutrient fertilizer containing S, B, Cu, Fe, Mn, Mo and Zn (Scotts MicroMa x, The Scotts Company, Marysville, OH) was applied to all plots on 23 July 2009 at the label recommended rate based on documented need for micronutrients by soil nutrient analysis. Irrigation was applied through nine drip lines (Jain Irrigation, Inc., Win ter Haven, FL) that were spaced 0.32 m apart with 0.20 m spacing between emitters and a flow rate of 0.65 gallons per minute /100 ft Plants were irrigated three times per week for 25 min at a rate of 1.80 cm of water applied per week starting at 0830 HR C umulative rainfall and irrigation was 30.46 inches during the 2008 study period and 31.75 inches for the 2009 study period (University of Florida, 2010) (Tables 2 2 and 2 3). Weeds were removed manually or spot t reated with glyphosate (Round Up, Monsanto, Creve Coeur, MO).

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134 Soil Sampling and Analysis Eight soil cores were collected initially (0 weeks after planting (WAP) and then every six weeks from each raised bed at a depth of 0 15 cm and composited. Samples we re air dried and sieved to pass a 2 mm screen before analysis for pH, EC, lime requirement (Adams Evans buffer test) and Mehlich 1 extractions were performed using the standard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Mehlich 1 soil extracts were analyzed for P, K, Ca, Mg, Zn, Mn, Cu and Fe using inductively coupled plasma atomic emission spectroscopy. Initial soil nutrient content and results of periodic soil testing are reported in Appendix A. Plant Growth a nd Shoot Dry Mass Plant growth measurements were taken at six week intervals and growth index (GI) was used as a quantitative indicato r of plant growth. Growth index was calculated as follows: GI (cm 3 ) = H W1 W2, where H is the plant height (cm), W1 i s the widest width of the plant (cm), and W2 is the width perpendicular to the widest width (cm). Plant shoots were cut at the soil surface at 18 weeks after planting (WAP). Plant tissue (leaves and stems) were dried to a constant mass at 40.5C and weighe d to determine shoot dry mass (g). Plant Quality and Chlorophyll Content Aesthetic quality ratings were determined visually for each plant cluster at six week intervals. Quality ratings considered canopy density, flowers, chlorosis and dieback ; a quality rating of 1 indicating a poor quality plant (low canopy density, few no flowers, and chlorosis) and a quality rating of 5 indicating an outstanding plant (dense leaf canopy, a good presence, high quality flowers and no signs of nutrient deficiencies or die back) (Shober et al., 2009)

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135 Chlorophyll content (SPAD) was determined every six weeks using a portable chlorophyll meter (SPAD 502, Minolta Corp., Ramsey, NJ). Six readings were taken per plant cluster (2 readings per plant) and averaged. Trends in SPAD measurements were correlated with results of chlorophyll anal ysis using a spectrophotometer (Wang, 2004) Flower Cover Index Flower cover index was determined by taking overhead photographs of each plant cluster every six weeks ( starting at 42 WAP) ). Color contrasts in the photographs were enhanced by altering the brightness using Adobe Photoshop Elements 6.0 (Adobe S ystems Inc. San Jose, CA). The background was removed using the cropping function. The photographs were then analyzed using a computer image analysis system (WinFolia, 2007b for leaf analysis, Regent Instruments Inc. Quebec, Canada ). Color groups were created for flower s, foliage and the background. The Winfolia software assigned each pixel to one of the 3 color groups and calculated the perce nt area covered by each color group. Flower cover index was calculated as: Flower Cover Index (unitless) = Flower / (Flower + Canopy) 100 where flower = the area covered by flowers and canopy = the area covered by canopy Foliar Nutrient Concentration Analysis Composite samples of foliar tissue (mature leaves) from each plant cluster were taken at the termination of the experiment (24 Aug. 2009). Tissue samples were ground to pass a #20 screen using Wiley mill (Arthur H. Thomas Co Scientific, Philadelp hia, PA) and dried at 110C for 7 d. Tissue digestions were completed using the standard methods of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu, 2009) Digested samples were analyzed for total kjeldahl nitrogen (TKN) using an Alpkem autoanal yzer, and Ca, Mg, P, K, Na, Cu, Mn, Fe, Zn, and B using inductively coupled atomic absorption spectroscopy.

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136 Statistical Analysis Plant measurements were analyzed with SAS software, Version 9.2 (SAS Institute Inc. Cary, NC). Repeated measurement models were estimated using the MIXED procedure to test for overall differences on quantitative variables (e.g., GI, SPAD) across years, WAP, WAP year interactions, year N fertilizer rate interactions, and WAP N fertilizer rate interactions. A block diagonal c ovariance matrix with identical first order autoregressive structure (AR(1)) on each block was specified. This structure incorporated correlation for all of the observations arising fr om the same experimental unit. No significant differences were found for WAP N fertilizer rate for GI of l iriope or for SPAD measuremen ts of lantana, bush daisy or c aladium. After modeling the data across time, significant treatment year or WAP year detailed statistical analysis of quantitative variables was performed for each measurement date (WAP) using SPSS 17.0 (SPSS, Inc., Chicago, IL). General linear models (GLM) were estimated using N fertilizer rate as a fixed effect. All pairwise comparisons SPAD and flower cover data using SPSS 17.0 to determine the effect of time on these variables. The P earson chi square statistic was calculated in SPSS 17.0 (SPSS, Inc., Chicago, IL) to test the general association between plant quality ratings and N fertilizer rates. Results and Discussion Lantana ( Lantana hybrida Plant growth and shoot dry mass Nitrogen fertilizer rate had no effect on the GI of lantana for the majority of the measur ement dates (Tables 4 3 and 4 4). There were significant N rate effects on the GI of

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137 lantana at 6, 30, and 96 WAP; growth was maximized when plants were fertili zed at the 6 lb/1000 ft 2 per yr rate at 6 WAP and the 2 lb/1000 ft 2 per yr rate at 30 and 96 WA P (Tables 4 3 and 4 4). Nitrogen fertilizer rate had an effect on the shoot dry mass of lantana. Plants receiving N at the 12 lb/1000 ft 2 per yr rate produced s ignificantly more shoot dry mass than the plants fertilized at the 0, 2, and 6 lb/1000 ft 2 per yr rate, but not the 4 lb/1000 ft 2 rate (Figure 4 1). However, plants fertilized at the 4 lb/1000 ft 2 rate produced more shoot biomass than plants rece iving no N fertilizer (Figure 4 1). Plant quality and chlorophyll content During the first year of the study (0 48 WAP), quality ratings generally improved with increasing N fertilizer rate, with above average quality plants attained when plants were fertilized with N at the 4 lb/1000 ft 2 per yr rate (Table 4 5). During the second year of the study (54 96 WAP), there were fewer differences in plant quality due to N fertilizer rate when compared with results from year one ( Tables 4 5 and 4 6 ). N fertilizer rate di d no t affect plant quality at 60 66 or 84 WAP. At 54 and 96 WAP, the 2 lb/1000 ft 2 per yr N fertilizer rate resulted in above average quality plants. Based on the results from both years of the study, we suggest that application of N to lantana at a rate of 2 lb/1000 ft 2 per yr will result in above average quality plants. Statistical analysis of SPAD measurements for lantana showed no significant WAP N rate interaction, allowing the data to be analyzed over the whole study. Over the course of the study, N f ertilizer rate affected the SPAD readings for lantana. Application of N at 4, 6, or 12 lb/1000 ft 2 produced lantana with higher chlorophyll content than plants fertilized at the 0 or 2 lb/1000 ft 2 per yr rates. However, fertilization of lantana with N at r ates higher than 4 lb/1000 ft 2 per yr did not significantly increase SPAD ratings ( Figure 4 2 ).

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138 Flower cover index Flower cover index results indicated that N fertilizer rate had no effect on the area of canopy covered by flowers for lantana at any time d uring the study (Table 4 9). Flower coverage was proportionate to the size of the lantana plant. Therefore, even though larger plants had more flowers, the proportion of the canopy covered in flowers was the same as for smaller plants. Tissue nutrient conc entration Nitrogen fertilizer rate had a strong effect on the concentrations of N in lantana tissue. In general, tissue N concentration increased as the N fertilizer rate increased (Figure 4 3 ). Tissue concentrations of P and K were also affected by N rate with concentrations decreasing with increasing N rate. In contrast, mean concentrations Mg, Ca, Fe, Mn, Zn and Cu were not affected by N fertilizer rate (Data not shown) and remained relatively constant (Table 4 10) No tissue nutrient results have been p ublished for lantana. Overall nitrogen requirement for lantana Based on the results of our study, we suggest that lantana performed best when fertilized at and N rate of 2 lb/1000 ft 2 per yr. F ertilization with N rates above the 4 lb/1000 ft 2 per yr did no t significantly increase the SPAD measurements or biomass of lantana Growth was not affected by N fertilization rate and quality of lantana was above average for the majority of the measurement dates with the fertilization rate of 2 lb/1000 ft 2 per yr B ush Daisy ( Gamolepis chrysanthemoides ) Plant growth and shoot dry mass Maximum growth index of bush daisy was attained for the majority of the measurement dates of the 96 week study when plants were fertilized with N at the 4 lb/1000 ft 2 per yr rate (6, 1 2, 18, 30, 42, 54, 66, 72, 78, 84, and 96 WAP) (Tables 4 3 and 4 4). Exceptions to this trend include d uring the first year of the study (6 48 WAP) plants fertilized with 6 and 12 lb/1000 ft 2

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139 were larger than plants receiving all other treatments at 24 an d 48 WAP. Also, d uring the second year of the study (54 96 WAP) plants fertilized with 6 and 12 lb/1000 ft2 were larger than plants receiving all other treatments at 60 and 90 WAP (Tables 4 3 and 4 4). Nitrogen fertilizer rate also had an effect on the sho ot dry mass of bush daisy. The plants receiving N at 6 and 12 lb/1000 ft 2 per yr produced significantly more shoot dry mass than the plants fertilized with the lower N treatments (Figure 4 4 ). Plant quality and chlorophyll content During the first year of the study (0 48 WAP), average or above (3 or above) quality ratings were attained when plants were fertilized with N at 4 lb/1000 ft 2 per yr (Table 4 5). During the second year of the study (54 96WAP), quality ratings generally improved with increasing N fertilization rate, with maximum quality attained when plants were fertilized at the N rate of 12 lb/1000 ft 2 per yr (Table 4 6). In both years, the quality of bush daisy fertilized at the 0 and 2 lb/1000 ft 2 per yr N rate tended to be below average (le ss than 3). However, plants fertilized at the 6, and 12 lb/1000 ft 2 rates were more likely to be rated as average o r above (3 or higher) (Tables 4 5 and 4 6) Therefore, we suggest that application of N to bush daisy at a rate of 6 lb/1000 ft 2 per yr will result in average quality plants under the con ditions of this study (Tables 4 5 and 4 6 ). Statistical analysis of SPAD measurements for bush daisy showed no significant WAP N rate interaction, allowing the data to be analyzed over the whole study. Applic ation of N at 12 lb/1000 ft 2 per yr produced bush daisy with higher chlorophyll content than plants fertilized at all other treatment rates ( Figure 4 5 ). Plants fertilized with 4 or 6 lb/1000 ft 2 per yr had lower chlorophyll content than the plant fertiliz ed with 12 lb/1000 ft 2 per yr but higher chlorophyll content than plants fertilized with 0 or 2 lb/1000 ft 2 per yr

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140 Bush daisy ( Gamolepis chrysanthemoides ) showed symptoms of a possible Fe deficiency with interveinal chlorosis on the younger leaves appeari ng by 54 WAP These symptoms continued on some plants through the end of the study period (96 WAP). All plants were treated several times with foliar applications of Fe and other micronutrients; however the plants did not recover from the stress. The root s of symptomatic plants were inspected and found to be healthy. Plants were scouted for insects that could cause damage and none were found. Therefore, no cause was determined for the plant symptoms; however, these symptoms were not stat istically related t o treatment. Flower cover index Nitrogen fertilization rate had a significant effect on flower cov er index of bush daisy (Table 4 9). At 42 WAP, plants receiving no N fertilizer had signif icantly less flower cover than plants receiving N at any rate. By 48 WAP, flower cover increased with increasing N rate, with plants receiving N at the 6 and 12 lb/1000 ft 2 per yr rate having significantly more flowers than plants fertilized at the 0, 2, and 4 l b/1000 ft 2 per yr rate. No N fertilizer effects occurred at 54 60, or 66 WAP, which was probably due to low flowering during the summer months (July and Aug.). At 72 WAP, flower cover index for plants receiving 12 lb/1000 ft 2 per yr N was significantly higher than plants fertilized at the lower rates. At 78 and 90 W AP, fertilization at the 12 lb/1000 ft 2 per yr N rate resulted in significantly higher percentage of flower cover than plants receiving no N fertilizer. At 96 WAP, the flower cover index appeared to increase with increasing N rate, with no significant diff erences in flower cover among plants receiving the three highest N rates. Overall, fertilization rate of bush daisy at the 4 lb/1000 ft 2 per yr N rate produced plants that had more flower cover than pla nts receiving no N fertilizer. In addition, N fertiliz ation at rates exceeding 4 lb/1000 ft 2 per yr did not significantly increase the proportion of the plant that wa s covered with flowers (Table 4 9).

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141 Tissue nutrient concentration Nitrogen fertilizer rate had a strong effect on the concentrations of N in bus h daisy tissue. In general, tissue N concentration increased as the N fertilizer rate increased, with plants fertilized at the 12 lb/1000 ft 2 per yr N rate having significantly higher tissue TKN than plants fertilized at rates lower than 4 lb/1000 ft 2 per yr (Figure 4 6 ). Tissue concentrations of P and K were also affected by N rate, with concentrations decreasing with increasing N rate ( d ata not shown ). In contrast, concentrations of Mg, Ca, Fe, Mn Zn and Cu were not affected by N fertilizer rate (Data no t shown) and remained relatively constant (Table 4 11 ) No tissue nutrient concentrations have been published for bush daisy Overall nitrogen requirement for bush daisy Based on the results of our study, we suggest that bush daisy performed best when fert ilized at an N rate of 4 lb/1000 ft 2 per yr. While fertilization with N at the 6 lb/1000 ft 2 per yr rate maximized plant quality, fertilization with N at the 4 lb/1000 ft 2 per yr resulted in growth and flower cover levels that were not significantly differ ent than bush daisy fertilized at higher rates. Plant SPAD readings increased with increasing N fertilization rate. Salvia ( Salvia longispicata farinacea Plant growth and shoot dry mass During the first year of the study (0 48 WAP), f ertilizations at 6 and 12 lb/1000 ft 2 per yr rate resulted in plants that had significantly higher GI in most weeks (Table 4 3). During the second year of the study (54 96WAP), GI was highest when plants were fertilized at the 4 lb/1000 ft 2 per yr rate ( Table 4 4). For the majority of the measurement dates over the 96 week study period, fertilization at rates exceeding 4 lb/1000 ft 2 per yr did not produce salvia plants with si gnificantly higher GI (Tables 4 3 and 4 4).

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142 Nitrogen fertilizer rate had an effe ct on the shoot dry mass of salvia (Figure 4 7 ). The plants receiving N at rates of 4 lb/1000 ft 2 per yr or higher produced significantly more shoot dry mass. Plant quality and chlorophyll content Plant quality ratings generally improved with increasing N fertilization rate from 6 66 WAP, with the plants receiving N at the 12 lb/1000 ft 2 per yr rate having the hi ghest quality ratings (Tables 4 5 and 4 6). The quality of all plants declined rapidly after 72 WAP t due to disease, regardless of N fertilizer rate. Only salvia fertilized at the 6 lb/1000 ft 2 per yr N rate retained a median rating that was average (Tables 4 6). During the first year of the study (0 48 WAP), fertilizations at 4,6 and 12 lb/1000 ft 2 per yr rate resulted in plants that had signi ficantly higher SPAD measurements in most weeks (6, 12, and 36 WAP) (Table 4 7). At 18 and 24 WAP there were no significant differences among treatments. At 30 WAP there were no significant differences in SPAD measurements among all plants receiving N. At 42 and 48 WAP fertilization at 12 lb/1000 ft 2 per yr rate produced plants with the highest SPAD measurements. During the second year of the study (54 96WAP), there were no significant differences among treatments at 60, 72, 78, 84, and 90 WAP. Fertilizat ions at 4, 6 and 12 lb/1000 ft 2 per yr rate resulted in plants that had significantly higher SPAD measurements a t 66 and 96 WAP and fertilizations at 12 lb/1000 ft 2 per yr rate resulted in plants that had significantly higher SPAD measurements at 54 WAP (T able 4 8). Based on the results from both years of the study, we suggest that application of N to salvia at a rate exceeding 4 lb/1000 ft 2 per yr will not increase the chlorophyll con tent of salvia plants (Tables 4 7 and 4 8). Flower cover index Flower cov er index results indicate that N fertilizer rate had little effect on the area of the canopy covered by flowers for salvia (Table 4 9). There were no significant differences among

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143 treatments at 42, 48, 72, and 78 WAP. At 54 WAP fertilization at 2, 4, and 6 lb/1000 ft 2 per year produced plants with significantly higher flower cover indices. At 60 WAP, all plants receiving N fertilizer had significantly more flower cover than those receiving no N fertilizer. At 66 WAP, there is a n inverse relationship betwee n flower cover and N rate, with salvia fertilized at N rates of 4, 6, and 12 lb/1000 ft 2 per year have less flower coverage than unfertilized plants. Based on the results of our study, there was little evidence that N fertilizer rate would influence the fl ower cover for salvia over the course of a growing season (Table 4 9) Tissue nutrient concentration No tissue nutrient results have been published for Salvia longispicata farinacea Nitrogen fertilizer rate had a strong effect on the concentrations of N i n salvia tissue. In general, tissue N concentration increased as the N fertilizer rate increased (Figure 4 8 ). Tissue concentrations of P and K were also affected by N rate with concentrations decreasing with increasing N rate (data not shown) In contrast mean tissue concentrations of Ca and Mg (Table 4 12 ) increased with increasing N rate (Data not shown) Mean tissue concentrations of Fe Mn, Zn and Cu were not affected by N fertilizer rate (Data not shown) and remained relatively consta nt over the cour se of the study (Table 4 12 ) No tissue nutrient results have been published for salvia, therefore no comparison with the resu lts of our study are available. Overall nitrogen requirement of salvia Based on the results of our study, we suggest that salvia p erformed best when fertilized at an N rate of 4 lb/1000 ft 2 per yr. While fertilization at the 12 lb/1000 ft 2 p er yr rate produced the highest quality ratings, salvia receiving N in excess of 4 lb/1000 ft 2 per yr did not have significantly higher GI, shoot dry mass, or SPAD readings. Nitrogen fertilizer rate is not likely to have an effect on flower cover.

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144 Liriope ( Liriope muscari Plant growth and shoot dry mass Statistical analysis of GI measurements for liriope showed no significant WAP N rate interaction, allowing the data to be analyzed over the whole study. Over the course of the study, liriope fertilized at an N rate of 12 lb/1000 ft 2 per yr had significa n tly higher GI than plants fertiliz ed at all lower rates (Figure 4 9 ). Nitroge n fertilizer rate had no effect on the shoot dry mass of liriope (Figure 4 10 ). Plant quality and chlorophyll content During the first and second year s of the study (0 48 WAP) and (54 96 WAP) all fertilizer rates produced plants with average (3) or hi gher quality ratings. Plants fertilized at the 12 lb/1000 ft 2 per yr N rate had the most above average ratings (4) (Table 4 5). Over the course of the study a fertilization rate of 4 lb/1000 ft 2 per yr was sufficient to produce high quality liriope (Tables 4 5 and 4 6) During the first year of the study, N rate had a significant effect on liriope SPAD readings (Table 4 7). At 6 and 12 WAP, liriope receiving no fertilizer had significantly lower SPAD readings than plants fertilized at the 2, 4, 6, or 12 2 l b/1000 ft 2 optimal rates. There was no significant N rate effect on liriope SPAD readings at 18 or 24 WAP. Fertilization of liriope at N rates higher than 4 lb/1000 ft 2 per yr did not increase SPAD measurements at 30 or 36 WAP. Plants fertilized at the 6 a nd 12 lb/1000 ft 2 per yr rate produced plants with significantly higher SPAD measurements at 42 WAP, while plants fertilized at the 12 lb/1000 ft 2 per yr N rate produced the highest SPAD ratings at 48 WAP. During the second year of the study, N rate contin ued to have a significant effect on liriope SPAD readings (Table 4 8 ). Plants receiving the fertilization rate of 2 lb/1000 ft 2 per yr produced optimal SPAD readings. Application of 2 lb/1000 ft 2 per yr was best for 66, 72, 84 and 96 WAP.

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145 A fertilization r ate of 6 lb/1000 ft 2 per yr was optimal for 60 and 90 WAP. A fertilization rate of 12 lb/1000 ft 2 per yr was optimal for 54 and 78 WAP. Based on the results from both years of the study, we suggest that application of N to liriope at a rate of 2 lb/1000 ft 2 per yr will result in high SPAD readings (Tables 4 7 and 4 8 ). Tissue nutrient concentration Nitrogen fertilization rate had a strong effect on the concentrations of N in liriope tissue. In general, tissue N concentration increased as the fertilizer rate increased, with plants receiving N at the 12 lb/1000 ft 2 rate having significantly higher tissue N concentrations than plants receiving 0, 2 or 4 lb/1000 ft 2 per yr (Figure 4 11 ). Tissue concentrations of P and K were also affected by N rate with concentr ations decreasing with N rate (D ata not shown) In contra st tissue concentrations of Fe, Mn, Zn and Cu were no t affected by N fertilizer rate (Data not shown) and remained relatively constant over the course of the study (Table 4 13) Tissue nutrient conce ntrations of N, P and Mg for liriope in ours study were within the range provided by Millls and Jones (1996) for iriope ( Liriope muscari ), while concentrations of K, Fe and Mn were lower than published values (Table 4 13). In contrast, tissue concentrations of Ca and Zn were higher for plants grown in our study than those reporte d by Mills and Jones (1996) Overall nitrogen requirement fo r liriope Based on the results of our study, we suggest that liriope performed best w hen fertilized at an N rate of 4 lb/1000 ft 2 per yr. While GI and tissue N were highest when liriope were fertilized at the 12 lb/1000 ft 2 per yr N rate, fertilization at rates exceeding 4 lb/1000 ft 2 per yr did not significantly improve plant quality, SPAD or shoot dry mass.

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146 Caladium ( Caladium bicolor Caladium plants were dormant from 24 42 WAP and again from 84 96 WAP, during which time no plant me asurements were recorded. Plant growth and shoot dry mass Nitrogen fertilizer rate affect ed growth of calad ium at 12 and 18 WAP (Tabl e 4 3). At 12 WAP, caladium GI was highest for plants fertilized at the 4, 6 and 12 lb/1000 ft 2 per yr N rates. By 18 WAP, fertil ization at N rates higher than 2 lb/1000 ft 2 per yr did not increase plant GI. Nitrogen rate significantly affected caladium GI during the second growth period (48 78 WAP) (Tables 4 3 and 4 4). At 54, 66, and 72 WAP plants fertilized with 2 lb/10 00 ft 2 per yr produced plants with the highest GI. Fertilization with 6 lb/1000 ft 2 per yr produced plants with the highest GI a t 48 and 60 WAP. For the majority of the measurement dates, fertilization of caladium at rate higher than 2 lb/1000 ft 2 per yr d id not result in an increase in plant GI (Tables 4 3 and 4 4). Shoot dry mass was not taken for caladiums because plants were dormant at 96 WAP. Plant quality and chlorophyll content At 12 and 18 WAP, fertilization of caladium at N rates of 2 lb/1000 ft 2 p er yr produced plants with averag e median plant quality ratings. Only plants receiving no N fertilizer had median rating l ower than average (<3) (Table 4 5). During the sec ond caladium growing period (48 78 WAP ), median plant quality ratings were highest when plants were fertilized at the 12 lb/1000 ft 2 per yr N rate at 60 and 72 WAP (Table 4 6). At 54 and 66 WAP, all N rates produced plants with average median quality ratings. By 78 WAP, all median plant quality ratings were below average regardless of N rate due to plants nearin g the end of their growth cycle (Table 4 6).

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147 This particular variety of c d white interveinal areas. The c aladium used in this study were grown in full sun and altho ugh this partic ular variety of c aladium has been shown to grow well in full sun some of the plants used in this study became sunburned. Statistical analysis of SPAD measurements for caladium showed no significant WAP N rate interaction, allowing the data to be analyzed over the whole study. Over the course of the study, the application of 2, 4, 6, or 12 lb/1000 ft 2 per yr produced caladiums with higher chlorophyll content than plants receiving no additional N. Therefore, the lowest fertilization rate of 2 lb/1000 ft 2 pe r yr was preferred ( Figure 4 12 ). However, it is possible that our SPAD results white leaves with green veining. This large white area made it difficult to sample the relatively small green portions of the leaf using the SPAD 502 meter Tissue nutrient concentration Results of tissue TKN analysis showed that plants receiving 4 lb/1000 ft 2 per yr had signi ficantly lower N concentrations (Figure 4 13 ). Tissue concent rations of P and K were affected by N rate with concentrations decreasing with N, while tissue concentrations of Ca and Mn, Zn, and Cu increased with N rate (D ata not shown) In contrast, mean tissue concentrations of Fe and Mg were not affected by N ferti lizer rate (Data not shown) and remained relatively constant throughout the study (Table 4 14 ) Tissue nutrient concentrations of N and Mg for this study were high compared to values of caladium tissue published by Harbaugh (1987) (Table 4 14 ) In contrast tissue concentrations of Mn and Zn tended to be lower than values published by Harbaugh (1987) (Table 4 14 ) The nutrient status of c aladium was low high for P, K, and Fe while it was in range high for Ca (Table 4 14 ).

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148 Overall nitrogen requirement for caladium Based on the results of our study, we suggest that caladium performed best when fertilized at an N rate of 4 lb/1000 ft 2 per yr. Fertilization at r rates exceeding 2 lb/1000 ft 2 per yr di d not appear to increase plant GI, quality, SPAD, or tissue N content.

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149 Figure 4 1 Shoot dry mass (g) of lantana ( Lantana hybrida grown in raised landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness z one 9b. P bars indicate the 95% confidence interval. A BC AB BC C Annual N Fertilizer Rate (per 1000 ft 2 ) Shoot dry mass (g)

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150 Figure 4 2. SPAD measurements of lantana ( Lantana hybrida landscape beds (2 008 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) B A AB AB B 0 lbs N 12 lbs N 6 lbs N 4 lbs N 2 lbs N SPAD Measurement

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151 Figure 4 3 Tissue concentratio ns of total Kjeldahl N (TKN) collected at 96 weeks after planting from lantana ( Lantana hybrida plants grown in raised landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. t difference test at P bars indicate the 95% confidence interval. A B B B B Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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152 Figure 4 4 Shoot dry mass (g) of bush daisy ( Gamolepis chrysanthemoides ) grown in raised landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. Mean P bars indicate the 95% confidence interval. A AB B C C Shoot dry mass (g) Annual N Fertilizer R ate (per 1000 ft 2 )

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153 Figure 4 5. SPAD measurements of lantana Bush daisy ( Gamolepis chrysanthemoides ) grown in raised landscape beds (20 08 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) 0 lbs N 12 lbs N 6 lbs N 4 lbs N 2 lbs N A B B C D SPAD Measurement

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154 Figure 4 6 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from bush daisy ( Gamolepis chrysanthemoides ) plants grown in raised landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. nt difference test at P bars indicate the 95% confidence interval. A AB B B B Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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155 Figure 4 7 Shoot dry mass (g) of salvia ( Salvia longispicata farinacea in raised landscape beds and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. AB AB A BC C Shoot dry mass (g) Annua l N Fertilizer Rate (per 1000 ft 2 )

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156 Figure 4 8 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from salvia ( Sal via longispicata farinacea landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. P bars indicate the 95% confidence interval. A B BC BC C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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157 Figure 4 9 Growth indices of Liriope ( landscape beds (2008 2010) and fertilized with at five N rates for 96 weeks in USDA hardiness zone 9b. Mean separation by Tukey P bars indicate the 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) A B B B B Mean GI (cm 3 ) A B B B B

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158 Figure 4 10 Shoot dry mass (g) of liriope ( landscape beds and fertilized with at five N rate s for 96 weeks in USDA hardiness zone 9b. P bars indica te the 95% confidence interval. A A A A A Shoot dry mass (g) Annual N Fertilizer Rate (per 1000 ft 2 )

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159 Figure 4 11 Tissue concentrations of total Kjeldahl N (TKN) collected at 96 weeks after planting from liriope ( Evergreen G landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. P b ars indicate the 95% confidence interval. A AB BC BC C Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN Percent

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160 Figure 4 12. SPAD measurements of c aladium ( Caladium ) grown in raised landscape beds (2008 2010) and fertilized with at five N rates for 78 weeks in USDA hardiness zone 9b. Mean P bars indicate the 95% confidence interval. Annual N Fertilizer Rate (per 1000 ft 2 ) A AB A AB B 0 lbs N 12 lbs N 6 lbs N 4 lbs N 2 lbs N SPAD Measurement

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161 Figure 4 13 Tissue concentrations of total Kjeldahl N (TKN) collected at 78 weeks after planting from caladium ( Caladium landscape beds and fertilized with at five N rates in USDA hardiness zone 9b. P bars indicate the 95% confidence interval A AB B AB AB Annual N Fertilizer Rate (per 1000 ft 2 ) Mean TKN percent

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162 Table 4 1. Total irrigation and rainfall volumes applied to perennial plant species grown in raised beds in USDA hardiness zone 9b between July 2008 and June 2009. Month Irrigation (in) Rainfall total z (in) Irrigation + rainfall (in) Cumulative rainfall (in) July 2.83 8.50 11.3 11.3 August 2.83 5.21 8.04 19.4 September 2.83 3.10 5.93 25.3 October 2.83 0.89 3.72 29.0 November 2.83 1.08 3.91 32.9 December 2.83 2.47 5.30 38.2 January 2.83 0.04 2.87 41.1 February 2.83 1.90 4.73 45.8 March 2.83 0.22 3.05 48.9 A pril 2.83 1.05 3.88 52.8 May 2.83 0.00 2.83 55.6 June 2.83 6.29 9.12 64.7 z Rainfall data collected at 2 m from the Florida Automated Weather Network station located approximately 805 m from the planting site (U niversity of Florida, 2010)

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163 Table 4 2. Total irrigation and rainfall volumes applied to perennial plant species grown in raised beds in USDA hardiness zone 9b between July 2009 and June 2010. Month Irrigation (in/month) Rainfall total z (in/month) Irr igation + rainfall (in) Cumulative rainfall (in) July 2.83 4.79 7.62 7.62 Aug ust 2.83 4.03 6.86 14.5 Sept ember 2.83 3.90 6.73 21.2 October 2.83 7.64 10.47 31.7 November 2.83 1.30 4.13 35.8 December 2.83 0.57 3.40 39.2 January 2.83 3.72 6.55 45.8 Fe bruary 2.83 0.67 3.50 49.3 March 2.83 3.62 6.45 55.7 April 2.83 1.53 4.36 60.1 May 2.83 5.94 8.77 68.9 June 2.83 2.80 5.63 74.5 z Rainfall data collected at 2 m from the Florida Automated Weather Network station located approximately 805 m from the pl anting site (University of Florida, 2010)

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164 Table 4 3. Mean growth index for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 0 48 weeks after planting in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000 ft 2 ) y Growth index z (m 3 ) 0 WAP x 6 WAP 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP 48 WAP Lantana hybrida 'New Gold' (lantana) 0 0.04 a w 0.08 c 0.37 a 0.92 a 0.99 a 1.03 b 0.05 a 1.70 a 3.65 a 2 0. 04 a 0.08 c 0.72 a 1.65 a 1.84 a 1.99 ab 0.08 a 2.26 a 5.22 a 4 0.04 a 0.11 bc 0.78 a 1.88 a 1.99 a 2.26 ab 0.09 a 2.52 a 6.19 a 6 0.04 a 0.16 ab 0.96 a 2.16 a 2.26 a 2.77 ab 0.07 a 2.54 a 7.17 a 12 0.04 a 0.21 a 1.18 a 3.29 a 3.64 a 4.04 a 0.12 a 2.86 a 7.41 a Gamolepis chrysanthemoides (bush daisy) 0 0.02 a 0.03 ab 0.04 b 0.05 c 0.07 d 0.12 c 0.14 b 0.28 c 0.41 d 2 0.02 a 0.03 b 0.06 ab 0.08 bc 0.14 c 0.26 b 0.34 a 0.55 b 0.85 c 4 0.02 a 0.03 ab 0.08 a 0.16 a 0.15 bc 0.36 ab 0.43 a 0.69 ab 1.19 b 6 0.02 a 0.03 ab 0.07 a 0.11 ab 0.23 a 0.39 a 0.43 a 0.87 a 1.54 a 12 0.02 a 0.04 a 0.07 a 0.16 a 0.20 ab 0.40 a 0.47 a 0.82 a 1.52 ab Salvia longispicata farinacea 'Mystic Spires' (salvia) 0 0.17 a 0.06 b 0.05 b 0.06 c 0.01 c 0.03 c 0.02 b 0.09 c 0. 15 d 2 0.05 a 0.07 b 0.09 b 0.13 bc 0.05 bc 0.13 c 0.11 b 0.49 c 0.48 cd 4 0.06 a 0.09 b 0.18 a 0.18 ab 0.09 b 0.42 b 0.39 a 1.11 b 1.21 bc 6 0.05 a 0.10 b 0.19 a 0.19 ab 0.10 b 0.54 ab 0.47 a 1.46 ab 1.59 ab 12 0.05 a 0.18 a 0.20 a 0.24 a 0.16 a 0.74 a 0.57 a 1.70 a 2.13 a Caladium bicolor 'White Christmas' (caladium) 0 -v 0.08 a 0.14 c 0.15 b ----0.02 b 2 -0.08 a 0.18 bc 0.25 ab ----0.02 b 4 -0.09 a 0.22 ab 0.27 a ----0.03 b 6 -0.11 a 0.24 ab 0.27 a ----0.0 7 b 12 -0.09 a 0.26 a 0.31 a ----0.04 ab z Growth index = height width 1 width 2. y 1 lb/1000 ft 2 1 x WAP = week after planting w v -indicates that data was not available due to plant dormancy.

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165 Table 4 4. Mean growth index for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 54 96 weeks after planting in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000 ft 2 ) y Growth index z (m 3 ) 54 WAP x 60 WAP 66 WAP 72 WAP 78 WA P 84 WAP 90 WAP 96 WAP Lantana hybridda 'New Gold' (lantana) 0 5.19 w a 1.88 a 4.58a 5.45 a 5.31 a 3.86 a 0.55 a 5.14 b 2 8.16 a 2.47 a 4.69 a 5.10 a 5.92 a 3.66 a 0.68 a 6.52 ab 4 9.96 a 3.06 a 5.15 a 5.47a 5.66 a 4.11 a 0.76 a 8.21 a 6 10.05 a 2.56 a 4.71 a 5.64 a 5.26 a 3.90 a 0.54a 5.73 ab 12 12.09 a 2.95 a 5.62 a 6.58 a 6.53 a 4.20 a 0.79 a 7.23 ab Gamolepis chrysanthemoides (bush daisy) 0 0.57 c 0.55 d 0.42 c 0.48 c 0.55 b 0.50 b 0.56 d 0.70 c 2 1.23 b 1.26 c 1.19 b 0.98 bc 1.01 b 0.90 b 1.15 cd 1.33 bc 4 1.60 ab 1.79 b 1.85 a 1.93 ab 2.10 a 1.96 a 2.26 bc 2.77 ab 6 1.89 a 2.40 a 1.94 a 2.31 a 2.90 a 2.32 a 3.30 ab 3.69 a 12 2.10 a 2.36 a 2.32 a 2.42 a 2.99 a 2.79 a 3.56 a 4.05 a Salvia longispicata farinacea 'Mystic Spires' (salv ia) 0 0.22 c 0.22 c 0.13 c 0.09 b 0.15 a 0.02 a 0.04 c 0.34 c 2 0.72 bc 0.86 bc 0.24 bc 0.20 ab 0.24 a 0.04 a 0.07 bc 0.46 bc 4 1.95 ab 2.36 ab 0.35 ab 0.33 a 0.54 a 0.17 a 0.20 bc 1.06 ab 6 2.39 a 2.65 ab 0.44 a 0.40 a 0.57 a 0.23 a 0.31 a 1.94 a 12 2.71 a 3.69 a 0.39 ab 0.39 a 0.38 a 0.12 a 0.29 ab 1.36 abc Caladium bicolor 'White Christmas' (caladium) 0 0.10 b 0.17 c 0.28 b 0.16 b -v ---2 0.14 ab 0.31 bc 0.52 a 0.29 ab ----4 0.15 ab 0.34 b 0.50 a 0.29 ab ----6 0.26 a 0. 43 ab 0.55 a 0.35 a ----12 0.20 ab 0.53 a 0.58 a 0.39 a ----z Growth index = height width 1 width 2. y 1 lb/1000 ft 2 1 x WAP = week after planting w v -indicates that data was not available due to plant dormancy.

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166 Table 4 5. Median visual quality ratings for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from 0 to 48 weeks after planting in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000 ft 2 ) z Plant quality rating 0 WAP y 6 WAP 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP 48 WAP Caladium bicolor 'White Christmas' (caladium) 0 5 2 2 2 -x ----2 5 2 3 3 -----4 5 2 3 3 -----6 5 2 3 3 -----12 5 2 3 3 -----Gamolepis chrysanthemoides (bush daisy) 0 5 2 2 2 1 1 1 1.5 1 2 5 2 3 3 3 2 2 2 3 4 5 2 4 4 3 3 3 3 4 6 5 3 3.5 4 4 3 3 3.5 5 12 5 3 3 4 4 4 3 4 5 Lantana hybrida 'New G old' (lantana) 0 5 2 3 3 3 2 1 3 4 2 5 2 3 4 3 3 1 4 5 4 5 3 4 5 4 4 1 5 5 6 5 3 4 5 4 3 1 4 5 12 5 4 5 5 5 4 2 5 5 Liriope muscari 'Evergreen G iant' (liriope) 0 5 3 3 3 3 3 3 3 3 2 5 3 3 4 3 3 3 3 3 4 5 3 3 4 3 3 3 4 4 6 5 3 3 3 3 3 3 3 4 12 5 4 3 4 4 4 4 4 4

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167 Table 4 5. Continued Annual N fertilizer rate (lb/1000 ft 2 ) z Plant quality rating 0 WAP y 6 WAP 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP Salvia longispicata farinacea 'Mystic S pires' (salvia) 0 5 1 1 1 1 1 1 1 2 5 1 1 1 2 2 1 2 4 5 1 2 3 3 3 2 3 6 5 2 3 2 3 3 3 4 12 5 3 3 3 4 4 3 4 z 1 lb/1000 ft 2 1 y WAP = week after planting x -indicates that data was not available due to plant dormancy

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168 Table 4 6. Median visual quality ratings for selected perennial plant species grown in raised landscape beds and fertilized at five N rates for 54 96 weeks (2008 2009) in USDA hardiness zone 9b Annual N fertilizer rate (lb/1000 ft 2 ) z Plant quality rating 54 WAP y 60 WAP 66 WAP 72 WAP 78 WAP 84 WAP 90 WAP 96 WAP Caladium bicolor 'White C hristmas' (caladium) 0 3 3 3 2 1 -x --2 3 3 3 2 2 ---4 3 3 3 2 1 ---6 3 3 3 2 2 ---12 3 4 3 3 2 ---Gamolepis chrysanthemoides (bush daisy) 0 1 1 1 1 1 1 1 2 2 3 2 2 1 1 1 1 1 4 3 3 2 2 2 2 3 6 4 3 3 2 3 2 3 3 12 5 4 3 2 3 3 3 3.5 Lantana hybrida 'New G old' (lantana) 0 3 4 4 3 2 1 1 3 2 4 4 4 3 2 1 1 4 4 4 4 4 3 2 1 1 4 6 4 4 4 2 2 1 1 4 12 5 4 4 3 3 1 2 4 Liriope muscari 'Evergreen G iant' (liriope) 0 3 3 3 3 3 3 3 3 2 3 4 4 3 4 4 4 4 4 3 3 3 3 4 3 3 4 6 3 3 3 3 3 3 3 4 12 4 4 4 4 4 3 4 5

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169 Table 4 6 Continued Annual N fertilizer rate (lb/1000 ft 2 ) z Plant quality rating 54 WAP y 60 WAP 66 WAP 72 WAP 78 WAP 84 WAP 90 WAP 96 WAP Salvia longispicata far inacea 'Mystic S pires' (salvia) 0 1 -2 1 1.5 1 -1.5 2 2 2 2 1 1 1 1 1 4 3 2 3 2 2 1 2 2 6 3 3 3 1 1 2 3 12 4 2 3 1 1 1 2 2 z 1 lb/1000 ft 2 1 y WAP = week after planting x -indicates that data was not available

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170 Table 4 7. Mean SPAD measurements for selected perennial plant species grown in raised landscape beds and fertilized at five N rates from0 to 48 weeks after planting in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000 ft 2 ) z Mean SPAD m easurements 6 WAP y 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP 48 WAP Salvia longispicata farinacea 'Mystic Spires' (salvia) 0 28.0 x b 31.7 b 35.2 a 39.7 a 37.5 b 36.2 c 35.4 d 33.9 b 2 30.1 b 31.6 b 30.7 a 39.7 a 39.2 ab 39.7 bc 37.9 cd 34.2 b 4 31.8 ab 34.0 ab 30.4 a 38.5 a 38.9 ab 44.9 a 40.1 bc 32.6 b 6 33.2 ab 34.8 ab 31.2 a 42.3 a 41.0 ab 43.5 ab 43.4 b 34.1 b 12 36.2 a 37.2 a 31.1 a 43.7 a 43.9 a 47.3 a 49.4 a 39.1 a Liriope muscari 'Evergreen G iant' (liriope) 0 59.0 b 58.3 b 57.2 a 57.2 a 55.7 b 47.4 c 42.1 c 44.9 d 2 62.7 ab 60.6 ab 59.6 a 58.2 a 55.8 b 53.1 bc 47.4 bc 50.1 c 4 65.6 a 61.3 ab 65.5 a 62.8 a 62.4 ab 56.6 ab 50.8 b 54.8 b 6 61.7 ab 60.0 ab 67.0 a 63.2 a 61.4 ab 57.6 ab 59.0 a 59.2 b 12 64.3 ab 65.7 a 65.5 a 57.4 a 67.2 a 62.2 a 62.3 a 65.0 a z 1 lb/1000 ft 2 1 y WAP = week after planting x

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171 Table 4 8. Mean SPAD measurements for selected perennial plant species grown in r aised landscape beds and fertilized at five N rates from 54 to 96 weeks after planting in USDA hardiness zone 9b. Annual N fertilizer rate (lb/1000 ft 2 ) z Mean SPAD m easurements 54 WAP y 60 WAP 66 WAP 72 WAP 78 WAP 84 WAP 90 WAP 96 WAP Salvia longispica ta farinacea 'Mystic Spires' (salvia) 0 31.9 x b 32.4 a 31.9 b 32.2 a 34.8 a 32.8 a 40.1 a 35.0 c 2 32.3 b 33.3 a 33.9 b 31.5 a 36.6 a 32.5 a 40.7 a 37.4 bc 4 32.4 b 32.4 a 34.8 ab 31.8 a 36.2 a 34.1 a 42.2 a 38.0 abc 6 32.9 b 32.9 a 35.4 ab 32.3 a 35. 6a 34.3 a 42.7 a 39.5 ab 12 35.8 a 33.5 a 38.7 a 37.9 a 35.7 a 33.7 a 43.6 a 41.5 a Liriope muscari 'Evergreen G iant' (liriope) 0 42.7 d 44.3 c 47.1 b 52.6 b 55.5 b 52.1 b 50.2 d 46.3 c 2 48.1 c 49.5 b 51.4 ab 59.1 ab 61.0 b 56.8 ab 53.9 cd 51.5 abc 4 49.9 bc 51.4 b 53.7 ab 58.4 ab 57.2 b 57.2 ab 56.6 bc 50.6 bc 6 55.2 b 55.5 a 54.7 ab 58.8 ab 60.6 b 59.4 a 61.4 ab 53.2 ab 12 60.9 a 58.2 a 58.8 a 65.4 a 67.4 a 59.7 a 62.4 a 56.8 a z 1 lb/1000 ft 2 1 y WAP = week after planting x

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172 Table 4 9. Mean flower cover indices for selected perennial plant species grown in raised l andscape beds and fertilized at five N rates from 0 to 48 weeks after planting in USDA hardiness zone 9b Annual N fertilizer rate (lb/1000ft 2 ) y Flower cover index z (% coverage) 42 WAP x 48WAP 54 WAP 60 WAP 66 WAP 72 WAP 78 WAP 90WAP 96 WAP Gamolepis ch rysanthemoides (bush daisy) 0 3.16 w b 3.00 c 1.01 a 2.42 a 0.86 a 0.42 b 5.56 b 5.56 b 0.44 c 2 8.16 a 4.74 c 0.89 a 3.24 a 1.54 a 0.41 b 6.77 ab 6.77 ab 2.03 bc 4 10.5 a 10.4 b 0.97 a 2.19 a 2.66 a 1.55 b 9.1 0 ab 9.1 0 ab 3.3 0 ab 6 10.01 a 14.8 a 1.2 4 a 1.47 a 2.97 a 2.30 b 11.2 ab 11.2 ab 4.65 a 12 10.3 a 15.1 a 1.14 a 2.36 a 3.06 a 4.97 a 8.88 a 8.89 a 5.17 a Lantana hybridda 'New Gold' (lantana) 0 19.7 a 11.5 a -v 6.79 ab 7.19 a 1.4 a 2.36 a --2 22.5 a 11.4 ab -6.96 a 5.71 ab 1.57 a 2 .38 a --4 21.5 a 10.9 ab -5.18 b 6.28 ab 1.65 a 1.61 a --6 22.8 a 11.5 ab -5.78 ab 5.46 ab 1.91 a 2.41 a --12 21.4 a 8.62 b -6.23 ab 4.56 b 1.99 a 2.42 a --Salvia longispicata farinacea 'Mystic Spires' (salvia) 0 25.0 a 36.2 a 18.6 c 27.8 b 39 .0 a 33.1 a 4.23 a --2 25.3 a 34.6 a 27.3 a 40.1 ab 33.0 ab 31.8 a 7.92 a --4 26.3 a 31.9 a 25.6 ab 41.8 a 25.7 bc 35.1 a 7.48 a --6 30.4 a 33.8 a 22.9 abc 41.0 ab 18.2 c 40.8 a 6.15 a --12 29.2 a 27.3 a 20.0 bc 44.0 a 22.5 bc 26.3 a 5.29 a --z Flower cover index = Flower Index = Flower/ (Flower + Canopy)*100 y 1 lb/1000 ft 2 x WAP = week after planting

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173 Table 4 10. Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from lantana ( Lantana hybrida USDA hardiness zone 9b. Eleme nt Mean concentration Range N, % 2.34 2.14 2.64 P, % 0.31 0.24 0.43 K, % 2.01 1.40 2.50 Ca, % 1.99 1.40 2.50 Mg, % 0.64 0.45 0.70 1 79.4 53.2 138 1 34.6 16.5 68.0 1 80.9 32.7 639

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174 Table 4 11. Leaf tis sue nutrient concentrations from tissue collected at 96 weeks after planting from bush daisy ( Gamolepis chrysanthemoides ) plants (n = 45) grown in raised beds in USDA hardiness zone 9b. Element Mean concentration Range N, % 2.65 2.43 3.03 P, % 0.42 0.3 0 0.63 K, % 2.58 1.70 3.40 Ca, % 1.68 1.40 2.00 Mg, % 0.37 0.32 0.45 1 65.4 40.2 148 1 68.4 27.0 200 1 68.7 46.6 104

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175 Table 4 12. Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from salvia ( Salvia longispicata farinacea = 45) grown in raised beds in USDA hardiness zone 9b. Element Mean concentration Range N, % 2.13 1.80 2.64 P, % 0.34 0.24 0.49 K, % 2.00 0.50 3.30 Ca, % 1.71 1.10 2.80 Mg, % 0.49 0.27 0.87 1 107 61.4 178 1 39.2 20.2 98.1 1 55.5 25.7 425

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176 Table 4 13. Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from liriope ( Evergreen G in USDA hardiness zone 9b. Element Liriope muscari published analysis z Current study m ean concentration Liriope muscari r ange N, % 1.25 2.57 1.56 1.28 1.86 P, % 0.12 0.42 0.27 0.12 0.35 K, % 1.07 2.42 1.46 0.70 2.20 Ca, % 0.36 0.86 1.45 1.00 2.30 Mg, % 0.10 0.49 0.22 0.12 0.33 1 56.0 164 67.2 32.9 125 1 19.0 298 60.4 15.2 207 1 25.0 78.0 63.0 37.5 91.1 z Values reported are for Liriope muscari in a container production nursery (Mills and Jones, 1996).

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177 Table 4 14. Leaf tissue nutrient concentrations from tissue collected at 96 weeks after planting from Caladium bicolor USDA hardiness zone 9b. Element Caladium c andidum published analysis z Current study m ean concentration Caladium ange N, % 3.20 4.30 4.45 4.06 4.85 P, % 0.52 0.55 0.77 0.48 1.04 K, % 3.20 3.26 2.10 4.90 Ca, % 1.20 1.70 2.10 1.20 3.10 Mg, % 0.13 0.19 0.47 0.40 0.58 1 53.0 184 40.1 25.15 64.0 1 76.0 610 120 24.9 273 1 114 250 102 60.6 171 z Values reported are for Caladium c andidum in a greenhouse production setting (Ha rbaugh, 1987)

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178 CHAPTER 5 CONCLUSIONS The basis for the current fertilizer recommendations for ornamental plants in Florida is unclear and limited. These recommendations are more focused on fertilization needs of trees and shrubs. Trees and shrubs may ha ve different nutritional requirements than other types of ornamental landscape plants (e.g., perennials, annuals, vines and groundcovers). Therefore, this research helps to validate the current fertilizer recommendations for a broader set of ornamental lan dscape plant types. The results of this research demonstrated that there is indeed a range of plant fertilizer requirements. Most of the N requirements of the species looked at in this study fell somewhere within the range provided by FYN and FL Green Ind ustries BMP manual recommendations for landscape fertilization. (Florida Yards and Neighborhoods Program, 2006 and Florida Department of Environmental Protection, 2008). Results of this study show that Zinnia elegans ) melampodium ( Melampodium divaricatum ) Bush Daisy ( Gameolepis chrysanthemoides ) Salvia longispicada ) and Caladium bicolo r) required 19.6 2 per yr (4 lb/1000 ft 2 per yr ). Results show that Antirrhinum majus ) Dianthus ( Dianthus chinensis ) Viola wittrockiana ) and Liriope ( Liriope muscari ) required 29.4 2 per yr (6 lb/1000 ft 2 per yr ). These nine specie s fell within the range designated as moderate high by FYN and FL Green Industries BMP manual recommendations for landscape fertilization (Florida Yards and Neighborhoods Program, 2006 and Florida Department of Environmental Protection, 2008). While lantana ( Lantana x hybrid a ) only required 9.8 2 per yr (2 lb/1000 ft 2 per yr ) which would be a basic moderate level of maintenance as defined by FYN and FL Green Industries BMP manual

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179 recommendations for landscape fertilization (Florida Yards and Neighborhoods Program, 2006 and Florida Department of Environmental Protection, 2008). However, there may be some species like v inca ( Catharanthus roseus ) which require N at levels above those currently recommended (12 lb/1000 ft 2 per yr ). Those plants that use high levels of N should either not be used in the landscape or they should be zoned together in order to minimize N loss to the environment. On the other side there are most likely additional species that require little if any N such as the lantana ( Lantana x hybrida) from th is study. Plants similar to this should also be planted in the same areas so as to minimize the amount of fertilizer applied to the landscapes. Plant zoning for fertilizer requirements would involve installing plants into the landscape that have similar f ertilization requirements close to each other or in the same areas of the landscape to create a fertilizer zone. Plant zoning based on nutrient requirements will result in more efficient fertilizer application, thus reducing nutrient losses to the environm ent. This research determined the nutrient requirements of specific ornamental plants, under the conditions of this study, results of which can later be used to create more precise fertilization recommendations. This research was the first part of a study constructed to validate and broaden N recommendations of Florida landscape plants. These recommendations will decrease the amount of nutrients that would be lost by means of leaching. It is important to note that this research only provides preliminary re sults. In order for plant zoning based on N requirement to be implemented, it is necessary to determine the N requirements of more plant types and species. Although it would be hard to test all species, it is important to test additional species in order t o determine a more accurate idea of what other

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180 species requirements may be. A pattern may perhaps be discovered among species or plant types that would be useful in determining the proper plant zone. This study used soil is commonly used in central Florid (USDA, 2009). The soil series is mapped as St. Johns fine sand (USDA NRCS, 2004). Therefore it will be important to test if plant requirements differ when the plants are grown in different soil types. If there are differe nces in requirements of one species based on soil type these differences must be analyzed to determine if there are trends among species and how N recommendations would change to reflect soil conditions. Also, the goal is to broaden ornamental recommendati ons for the state of Florida and since these are landscape trials, the project should be replicated in other parts of the state (North Florida and South Florida). Future research should also include testing leachate volume and nutrient content in the leach ate. This will help determine how much N the plants are using and how much is lost to the environment. Plants that require more N could be using a higher percentage of the higher volume of fertilizer that is applied but the nutrients lost to the environmen t from this higher application could also be greater than the N lost by means of a lower application. Therefore, N uptake efficiency must be determined. In addition to plant uptake efficiency plant spacing in relation to N leaching and plant performance sh ould also be examined in order to further minimize N loss to the environment.

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181 APPENDIX RESULTS OF PERIO D IC SOIL ANALYSIS Soil pH, Electrical Conductivity and Mehlich 1 Nutrient Results During the first year of the study (0 48 WAP) mean pH ranged from 5. 4 6.5. During t he second year of the study (48 96 WAP) the mean pH ranged from 5.7 7.1. Most plots were within an acceptable range for the majority of the growing period. Treatment did not have a significant difference on pH for first or second year of the study. During the first year of the perennial study (0 48 WAP) mean EC ranged from 44.48 557.4 s/cm. During the second year of the study (48 96 WAP) the mean EC ranged from 70.31 202.37 s/cm. Both first and second year EC levels were within the rang e that most plants are tolerant (Shober, 2009). According to Kidde r et al. (2009) Phosphorus levels were very high with a mean of 215 mg/L. Potassium levels were very medium with a mean of 40.0 mg/L. and Magnesium levels were high with a mean of 32.9 mg/L (Kidder et. al. 2009). According to UF/IFAS analytical services laboratories interpretations of micronutrient soil test report for Mn, Zn and Cu Soil Mn concentrations were low with a mean Mn of 0.65 mg/kg, soil Zn concentrations were low with a mean of 1 67 mg/ kg and soil Cu concentrations were high with a mean of 1.2 mg/kg. Mean Ca was 457 and mean Fe was 4.42 mg/kg.

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182 Table A 1 Mean soil nutrient content (Mehlich 1) of raised flower beds fertilized at five N rates in 2008 2010 for 6 48 weeks after pla nting (WAP) fertilized at five N rates in 2008 2010. Annual N fertilizer rate (lb/1000 ft 2 ) Mean soil nutrient content (Mehlich 1) 6 WAP Z 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP 48 WAP Phosphorus (g/kg) 0 198 y a 196 a 250 a 292 a 274 a 383 a 296 a 3 41 a 2 185 a 204 a 210 a 274 a 287 a 364 a 322 a 366 a 4 180 a 182 a 229 a 304 a 259 a 357 a 323 a 396 a 6 204 a 183 a 209 a 263 a 269 a 337 a 309 a 357 a 12 190 a 177 a 205 a 324 a 255 a 321 a 284 a 411 a Potassium (g/kg) 0 15.6 a 23.7 a 16.6 a 76. 1 a 60.3 a 118 a -x 57.2 a 2 10.4 ab 15.1 a 19.4 a 42.7 ab 38.5 ab 92.8 a -31.3 ab 4 7.01 bc 16.3 a 15.0 a 38.2 b 48.6 ab 88.1 a -21.2 b 6 5.65 bc 16.3 a 9.85 a 36.1 b 31.6 ab 69.6 a -18.7 b 12 4.61 d 12.5 a 8.77 a 21.2 b 20.3 b 101 a -18.4 b Magnesium (g/kg) 0 36.6 a 37.6 a 39.2 a 35.9 a 37.5 43.4 a 33.6 a 30.4 a 2 27.9 a 40.8 a 30.1 a 24.1 a 32.3 37.8 a 32.4 a 28.3 a 4 24.2 a 26.9 a 34.9 a 22.3 a 23.9 30.4 a 34.6 a 25.1 a 6 35.4 a 28.8 a 45.4 a 35.3 a 41.7 39.6 a 39.2 a 20.5 a 12 19.6 a 21.7 a 22.0 a 31.6 a 31.7 33.9 a 27.9 a 16.4 a Manganese (g/kg) 0 BD w BD BD BD BD 0.16 a 0.15 a 0.08 a 2 0.35 a BD BD BD BD 0.09 a 0.08 a 0.08 a 4 BD BD BD BD BD 0.16 a 0.10 a 0.13 a 6 BD BD BD BD BD 0.15 a 0.08 a 0.13 a 12 BD BD BD BD BD 0.18 a 0.09 a 0.10 a

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183 Table A 1. Continued Annual N fertilizer rate (lb/1000 ft 2 ) Mean soil nutrient content (Mehlich 1) 6 WAP z 12 WAP 18 WAP 24 WAP 30 WAP 36 WAP 42 WAP 48 WAP Zinc (g/kg) 0 0.60 a 0.68 a 0.37 ab 0.32 a 0.66 a 0.95 ab 0.45 a 0.33 a 2 0.53 a 0.88 a 0.35 ab 0.36 a 0.65 a 0.7 0 ab 0.26 a 0.34 a 4 0.54 a 0.66 a 0.49 a 0.42 a 0.56 a 1.06 a 0.35 a 0.41 a 6 0.49 a 0.89 a 0.27 b 0.77 a 0.50 a 0.58 ab 0.27 a 0.25 a 12 0.54 a 0.77 a 0.23 b 0.32 a 0.44 a 0.55 b 0.34 a 1.10 a Copper (g/kg) 0 0.39 a 0.61 a 0.07 a 0.14 a 0.24 a 0.78 a 0.72 a 0.63 a 2 0.30 a 0.53 a 0.11 a 0.11 a 0.20 a 0.89 a 0.56 a 0.57 a 4 0.33 a 0.56 a 0.09 a 0.18 a 0.29 a 0.90 a 0.60 a 0.70 a 6 0.28 a 0.62 a 0.05 a 0.03 a 0.22 a 0.80 a 0.51 a 0.56 a 12 0.33 a 0.44 a 0.12 a 0.14 a 0.18 a 0.82 a 0.61 a 0.78 a Iron (g/kg) 0 5.25 a 7.82 a 4.96 a 4.99 a 6.43 a ---2 3.90 a 6.25 a 3.11 a 4.86 a 5.62 a ---4 3.43 a 6.92 a 2.85 a 4.02 a 8.36 a ---6 3.22 a 7.33 a 2.92 a 4.07 a 5.21 a ---12 4.66 a 6.21 a 2.79 a 3.48 a 5.66 a ---Calcium (g/kg) 0 465 a 558 a 825 a 453 a 398 a 412 a 340 a 307 a 2 394 a 620 a 442 a 346 a 450 a 397 a 317 a 295 a 4 458 a 630 a 479 a 472 a 395 a 402 a 428 a 344 a 6 504 a 521 a 826 a 638 a 592 a 530 a 466 a 395 a 12 348 a 446 a 347 a 353 a 380 a 505 a 310 a 258 a z WAP = week after planting y P x indicates data not collected w BD indicates measured value was below the method detection limit

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184 Table A 2 Mean soil nutrient content (Mehlich 1) of raised flower beds fertilized at five N rates in 2008 2010 for 54 90 weeks after planting fer tilized at five N rates in 2008 2010. Annual N fertilizer rate (lb/1000 ft 2 ) Mean soil nutrient content (Mehlich 1) 54 WAP z 60 WAP 72 WAP 84 WAP 90 WAP Phosphorus (g/kg) 0 296 y a 135 104 a 32.7 a 59.1 a 2 306 a 119 102 a 34.1 a 58.6 a 4 260 a 124 98 .9 a 34.8 a 53.7 a 6 290 a 105 99.1 a 24.8 a 65.6 a 12 290 a 108 106 a 38.3 a 53.7 a Potassium (g/kg) 0 71.2 a 46.6 a 71.7 a 46.8 a 23.1 a 2 68.9 a 26.1 b 72.1 a 34.5 ab 30.6 a 4 34.6 a 20. 4 b 48.1 a 26.5 ab 19.3 a 6 49.9 a 22.5 b 77.7 a 19.4 ab 23 .4 a 12 40.5 a 8.86 b 33.2 a 14.1 b 11.1 a Magnesium (g/kg) 0 33.0 a 46.8 ab 42.8 a 39.1 a 52.7 a 2 30.6 a 54.0 a 41.5 a 30.7 a 53.7 a 4 13.6 a 27.2 b 36.9 a 42.5 a 46.9 a 6 18.9 a 29.8 ab 28.1 a 40.5 a 60.8 a 12 16.5 a 23.9 b 22.8 a 18.3 a 24.1 a Manganese (g/kg) 0 -x -2.10 a 1.35 a 2.19 a 2 --1.43 a 1.86 a 1.44 a 4 --3.08 a 1.72 a 2.45 a 6 --2.81 a 1.10 a 1.17 a 12 --0.55 a 0.36 a 1.22 a

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185 Table A 2. Continued Annual N fertilizer rate (lb/1000ft 2 ) Mean Soil Nutrient Content (Mehlich 1) 54 WAP Z 60 WAP 72 WAP 84 WAP 90 WAP Zinc (g/kg) 0 3.34 a 5.09 a 2.06 a 1.76 a 4.62 a 2 4.54 a 4.44 a 2.44 a 2.38 a 3.70 a 4 3.72 a 3.23 a 3.95 a 2.74 a 4.40 a 6 4.63 a 5.24 a 4.44 a 3.29 a 3.61 a 12 3.91 a 3.35 a 2.12 a 1.21 a 3.89 a Copper (g/kg) 0 2.60 a 3.74 a 1.70 a 0.91 a 2.42 a 2 3.08 a 3.61 a 1.94 a 1.44 a 2.24 a 4 2.41 a 3.76 a 3.05 a 1.69 a 2.23 a 6 2.51 a 3.83 a 2.25 a 1.47 a 2.02 a 12 4.22 a 3.02 a 2.14 a 1.73 a 2.37 a Iron (g/kg) 0 -6.70 ab 3.85 a 0.39 a 2.23 a 2 -4.35 b 4.50 a 0.89 a 1.63 a 4 -9.21 a 5.50 a 1.33 a 2.08 a 6 -7.54 ab 5.69 a 0.52 a 1.53 a 12 -6.13 ab 6.02 a 2.19 a 2.15 a Calcium (g/kg) 0 326 ab 623 a 430 a 452 a 524 a 2 390 a 556 a 509 a 376 a 660 a 4 178 b 423 a 484 a 358 a 493 a 6 270 ab 919 a 366 a 471 a 728 a 12 168 b 570 a 383 a 359 a 486 a z WAP = week after planting y P x indicates data not collected

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186 LIST OF REFERENCES Black, R.J. 2006. Bedding plants: Selection, establishment and maintenance. CIR1134. Univ. Florida Inst. Food Agric. Sci., Gainesville. Black, R.J. and B. Tjia. 2000. Annual flowers for Florida. CIR 569. Univ. Florida Inst. Food Agric. Sci., Gainesville. Brabec, E., S. Schulte, and P.L. Richards. 2002. Impervious surfaces and water quality: A review of current literature and its implications for watershed planning. J. Planning Literature 16:499 514. Brady, N.C. and R.R. Weil. 2002. The nature and properties of soils. Prentice Hall, Upper Saddle River, NJ. Britto, D.T., M.Y. Siddiqi, A.D.M. Glass, and H.J. Kronzucker. 2001. Futile transmembrane NH 4 + cycling: A cellular hypothesi s to explain ammonium toxicity in plants. Proc. Natl. Acad. Sci. U.S.A. 98:4255 4258. Broschat, T.K., D.R. Sandrock, M.L. Elliott, and E.F. Gilman. 2008. Effects of fertilizer type an quality and nutrient content of established landscape plants in Florida. HortTechnology 18:278 285. Cabrera, R. 2003. Less is more. Amer. Nurseryman 197:40. Cabrera, R.I. and D.R. Devereaux. 1999. Crape myrtle post transplant growth as affected by nitrogen nutrition during nursery production. J. Amer. Soc. Hort. Sci. 124:94 98 Cardenas Navarro, R., L. Lopez Perez, P. Lobit, R. Ruiz Corro, and V.C. Castellanos Morales. 2006. Effects of nitrogen source on growth and development of strawberry plants. J. Plant Nutr. 29:1699 1707. Cockx, E.M. and E.H. Simonne. 2003. Reduction of th e impact of fertilization and irrigation on processes in the nitrogen cycle in vegetable fields with BMPs. HS948. Univ. Florida Inst. Food Agric. Sci., Gainesville. Creel, R. and R.J. Kessler. 2007. Greenhouse production of bedding plant snapdragons. Alaba ma Coop. Ext. Serv., Auburn. 18 Oct. 2010. < http://www.aces.edu/pubs/docs/A/ANR 1312/ Dubois, J.B., S.L. Warren, and F.A. Blazich. 2000. Nitrogen nutrition of containerized Anemone x hybrid J. Envir on. Hort. 18:145 148. Erickson, J.E., J.L. Cisar, J.C. Volin, and G.H. Snyder. 2001. Comparing nitrogen runoff and leaching between newly established St. Augustinegrass turf and an alternative residential landscape. Crop Sci. 41:1889 1895. Ferrini, F. and M. Baietto. 2006. Response to fertilization of different tree species in the urban environment. Arboriculture Urban For. 32:93 99.

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187 Florida Department of Environmental Protection. 2002. Best management practices for protection of water resources in Florida. Florida Dept. Environ. Protection, Tallahassee. 30 April 2008. < http://www.dep.state.fl.us/central/Home/MeetingsTrai ning/FLGreen/BMP_Book_final. pdf Florida Yards and Neighborhoods Program. 2006. A guide to Florida friendly landscaping. Univ. Florida Inst. Food Agric. Sci., Gainesville, FL. Gamrod, E.E. and H.L. Scoggins. 2006. Fertilizer concentration affects growth and follar elemental concentration of Strobilanthes dyerianus HortScience 41:231 234. Gilman, E.F. and T.H. Yeager. 1990. Fertilizer type and nitrogen rate affects field grown laurel oak and Japanese ligustrum. Proc. Florida State Hort. Soc. 103:370 372. Gilman, E.F., T.H. Yeager, and D. Kent. 2000. Fertilizer rate and type impacts magnolia and oak growth in sandy landscape soil. J. Arboricultu re 26:177 181. Gorska, A., Q. Ye, N.M. Holbrook, and M.A. Zwieniecki. 2008a. Nitrate control of root hydraulic properties in plants: Translating local information to whole plant response. Plant Physiol. 148:1159 1167. Gorska, A., A. Zwieniecka, N.M. Holbro ok, and M.A. Zwieniecki. 2008b. Nitrate induction of root hydraulic conductivity in maize is not correlated with aquaporin expression. Planta 228:989 998. Gunes, A., A. Inal, and M. Aktas. 1996. Reducing nitrate content of NFT grown winter onion plants (Al lium cepa L) by partial replacement of NO3 with amino acid in nutrient solution. Scientia Hort. 65:203 208. Harbaugh, B.K. 1987. Foliar analysis standards for nitrogen, phosphorus and potassium in Caladium X hortulanum 'Birdsey'. Acta Hort.:249 255. Hipp, B .W., B.J. Simpson, and P.S. Graff. 1988. Influence of nitrogen and phosphorus on growth and tissue N and P concentration in Salvia greggii J. Environ. Hort. 6:59 61. Hipp, B.W., B.J. Simpson, and P.S. Graff. 1989. Influence of phosphorus on nitrogen ferti lizer requirement of Melampodium leucanthum (Blackfoot Daisy) grown in perlite vermiculite medium. J. Environ. Hort. 7:83 85. Israel, G.D. and G.W. Knox. 2001. Reaching diverse homeowner audiences with environmental landscape programs: comparing lawn servi ce users and nonusers. AEC 363. Univ. Florida Inst. Food Agric. Sci., Gainesville. Jampeetong, A. and H. Brix. 2009. Effects of NH4+ concentration on growth, morphology and NH 4 + uptake kinetics of Salvinia natans Ecol. Eng. 35:695 702.

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188 Kidder, G., E.A. Ha nlon, T.H. Yeager, and G.L. Miller. 2009. IFAS standardized fertilization recommendations for environmental horticulture crops. SL 141. Univ. Florida Inst. Food Agric. Sci., Gainesville. Latimer, J.G., S.K. Braman, R.B. Beverly, P.A. Thomas, J.T. Walker, B Sparks, R.D. Oetting, J.M. Ruter, W. Florkowski, D.L. Olson, C.D. Robacker, M.P. Garber, O.M. Lindstrom, and W.G. Hudson. 1996. Reducing the pollution potential of pesticides and fertilizers in the environmental horticulture industry: II. Lawn care and l andscape management. HortTechnology 6:222 232. Lewitus, A.J. and A.F. Holland. 2003. Initial results from a multi institutional collaboration to monitor harmful algal blooms in South Carolina. Environ. Monitoring Assessment 81:361 371. Line, D.E., N.M. Whi te, D.L. Osmond, G.D. Jennings, and C.B. Mojonnier. 2002. Pollutant export from various land uses in the upper Neuse River Basin. Water Environ. Res. 74:100 108. Lloyd, J.E., D.A. Herms, M.A. Rose, and J. Van Wagoner. 2006. Fertilization rate and irrigatio n scheduling in the nursery influence growth, insect performance, and stress tolerance of 'Sutyzam' crabapple in the landscape. HortScience 41:442 445. Macz, O., E.T. Paparozzi, and W.W. Stroup. 2001. Effect of nitrogen and sulfur applications on pot chrys anthemum production and postharvest performance. I. Leaf nitrogen and sulfur concentrations. J. Plant Nutr. 24:111 129. Matson, P.A., W.J. Parton, A.G. Power, and M.J. Swift. 1997. Agricultural intensification and ecosystem properties. Science 277:504 509. Miller, A.J. and M.D. Cramer. 2004. Root nitrogen acquistion and assimilation. Plant Soil 274:1 36. Mills, H.A. and J.B. Jones. 1996. Plant analysis handbook II. A practical sampling, preparation, analysis and interpretation guide. MicroMacro Publishing, Inc., Athens, GA. Mylavarapu, R.S. 2009. UF/IFAS Extension Soil Testing Laboratory (ESTL) analytical procedures and training manual. CIR 1248. Univ. Florida Inst. Food Agric. Sci., Gainesville. Nau, J. 1996. Ball perennial manual: Propagation and prodcutio n. Ball Publishing, Batavia, IL. Neely, D. 1980. Tree fertilization trials in Illinois. J. Arboriculture 6:271 273. Oram, B. 2010. Nitrates and nitrites in drinking water. Wilkes Univ., Center Environ. Qual., Environ. Eng. Earth Sci. 24 Aug 2010. < http://www.water research.net/nitrate.htm

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189 Qualls, R.J., J.M. Scott, and W.B. DeOreo. 2001. Soil moisture sensors for urban landscape irrigation: Effectiveness and reliability. Journal of the American Water Resources Association 37:547 559. Raven, P.H., R.F. Evert, and S.E. Eichhorn. 2005. Biology of plants. W.H. Freeman and Company, New York, NY. Romero, F.R., H.G. Taber, and R.J. Gladon. 2006. Nitrogen source and concentration affect growth and performance of bedding plant impatiens. J. Plant Nutr. 29:1315 1326. Rose, M.A. 1999. Nutrient use patterns in woody perennials: Implications for increasing fertilizer efficiency in field grown and landscape ornamentals. HortTechnology 9:613 617. Rose, M.A. and B. Bie rnacka. 1999. Seasonal patterns of nutrient and dry weight accumulation in Freeman maple. HortScience 34:91 95. Saha, S.K., L.E. Trenholm, and J.B. Unruh. 2005. Effect of fertilizer source on water use of st. augustinegrass and ornamental plants. HortScien ce 40:2164 2166. Saha, S.K., L.E. Trenholm, and J.B. Unruh. 2007. Effect of fertilizer source on nitrate leaching and st. augustinegrass turfgrass quality. HortScience 42:1478 1481. Sartain, J.B., L.T. Trenholm, E.F. Gilman, T.A. Obreza, and G. Toor. 2009. Frequently asked questions about landscape fertilization for Florida friendly landscaping ordinances. ENH 1115. Univ. Florida Inst. Food Agric. Sci., Gainesville. Scholberg, J.M., L. Zotarelli, R.S. Tubbs, M.D. Dukes, and R. Munoz Carpena. 2009. Nitrogen uptake efficiency and growth of bell pepper in relation to time of exposure to fertilizer solution. Commun. Soil Sci. Plant Anal. 40:2111 2131. Schulte, J.R. and C.E. Whitcomb. 1975. Effects of soil amendments and fertilizer levels on the establishment of silver maple. J. Arboriculture 1:192 195. Secretariat Tree Care Industry Association. 2008. Standard practices for tree care operations: Tree, shrub, and other woody plant maintenance (fertilization). Tree Care Ind. Assoc., Inc., Londonderry. 18 Oct. 2010. < http://www.treecareindustry.org/pdfs/A300Part2D1V1 PubRev09 11%2708.pdf Shober, A.L. 2009. Soils and fertilizers for master gardeners: The Florida gardeners guide to landscape fertilizers. SL 266. Univ. Florida Inst. Food Agric. Sci., Gainesville. Shober, A.L., S. Davis, M.D. Dukes, G.C. Denny, S.P. Brown, and S. Vyapari. 2009. Performance of Florida landscape plants when irrigated by ET based controllers and time base d methods. J. Environ. Hort. 27:251 256.

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190 Shober, A.L., G.C. Denny, and T.K. Broschat. 2010. Management of fertilizers and water for ornamental plants in urban landscapes: current practices and impacts on water resources in Florida. HortTechnology 20:94 106 Smith, E. 1978. Fertilizing trees and shrubs in the landscape. J. Arboriculture 4:157 161. Smith, M.A., G.C. Elliot, and M.P. Bridgen. 1998. Calcium and nitrogen fertilization of Alstroemeria for cut flower production. HortScience 33:55 59. Smith, T. 199 9. Some thoughts about soil pH, fertilizers and lime. Washington State Univ., Wenatchee. 22 Aug. 2010. < http://www.ncw.wsu.edu/treefruit/soil/lime.htm Taiz and Zeiger. 2006. Plant physiology. S inauer Associates Inc., Sunderland, MA. Tang, Z., B.A. Engel, B.C. Pijanowski, and K.J. Lim. 2005. Forecasting land use change and its environmental impact at a watershed scale. J. Environ. Manage. 76:35 45. Tjia, B. and R.J. Black. 2003. Fibrous rooted be gonias for Florida. CIR 449. Univ. Florida Inst. Food Agric. Sci., Gainesville. University of Florida. 2010. Florida automated weather network, report generator. Univ. Florida Inst. Food Agric. Sci., Gainesville. 21 Oct. 2010. << http://fawn.ifas.ufl.edu/data/reports/ USDA NRCS. 2004. United States Department of Agriculture Official Soil Series Descriptions. December 12, 2008. < h ttp://soils.usda.gov/technical/classification/osd/index.html Vagts, T. 2005. Nitrogen fertilizers and soil pH. Iowa State University Extension, Carroll. 23 Aug. 2010. < http: //www.extension.iastate.edu/nwcrops/fertilizer_and_soil_ph.htm van de Werken, H. 1969. Responses of shade trees to fertilization. Tennessee Farm Home Sci. 72:2 4. van de Werken, H. 1981. Fertilization and other factors enhancing the growth of young shade trees. J. Arboriculture 7:33 37. van den Heever, E., J. Allemann, and J.C. Pretorius. 2008. Influence of nitrogen fertilizers on yield and antifungal bioactivity of Tulbaghia violacia L. Human Expt. Toxicology 27:851 857. van Iersel, M.W., R.B. Beverly, P .A. Thomas, J.G. Latimer, and H.A. Hills. 1998a. Fertilizer effects on the growth of impatiens, petunia, salvia, and vinca plug seedlings. HortScience 33:678 682. van Iersel, M.W., R.B. Beverly, P.A. Thomas, J.G. Latimer, and H.A. Mills. 1999. Nitrogen, ph osphorus, and potassium effects on pre and post transplant growth of salvia and vinca seedlings. J. Plant Nutr. 22:1403 1413.

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19 1 van Iersel, M.W., P.A. Thomas, R.B. Beverly, J.G. Latimer, and H.A. Mills. 1998b. Nutrition affects pre and posttransplant growt h of impatiens and petunia plugs. HortScience 33:1014 1018. Vasas, V., C. Lancelot, V. Rousseau, and F. Jordan. 2007. Eutrophication and overfishing in temperate nearshore pelagic food webs: a network perspective. Marine Ecol. Progress Series 336:1 14. von Wiren, N., S. Gazzarrini, A. Gojon, and W.B. Frommer. 2000. The molecular physiology of ammonium uptake and retrieval. Current Opinion Plant Biol. 3:254 261. Wallace, T. 1943. The diagnosis of mineral deficiencies in plants by visual symptoms. Univeristy of Bristol Agriculture and Horticulture Research Station, Bristol, UK. Wang, H., Y. Inukai, and A. Yamauchi. 2006. Root development and nutrient uptake. Critical Rev. Plant Sci. 25:279 301. Wang, Q. 2004. Nondestructive and rapid estimation of leaf chlorop hyll and nitrogen status of peace lily using a chlorophyll meter 1. J. Plant Nutr. 27:557 569.

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192 BIOGRAPHICAL SKETCH Gitta Shurberg was born in Warrenton, Virginia. The youngest of three children, she grew up in The Plains, VA. After graduating from West town School, PA in 2001, she earned her B.A. in English Literature with a Spanish minor from the University of Delaware in 2005. Upon graduation she began work as a laboratory assista nt in a Soil and Water Science D epartment laboratory at the University of Delaware. In 2006 she moved to Florida to take the position of Biological Scientist for a soil scientist at the University of Florida. In 2008 she began wor k on her Masters degree in the D epartment of Environmental Horticulture. Upon completion of her M.S program, Gitta will continue her work as a Biological Scientist at UF.