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Effect of Nitrogen Sources on St. Augustinegrass and Zoysiagrass Responses

Permanent Link: http://ufdc.ufl.edu/UFE0043880/00001

Material Information

Title: Effect of Nitrogen Sources on St. Augustinegrass and Zoysiagrass Responses
Physical Description: 1 online resource (140 p.)
Language: english
Creator: Castillo, Ronald
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: color -- fertilizer -- quality -- soluble -- turfgrass
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: St. Augustinegrass (Steotaprum secundatum (Walt) Kuntze) and zoysiagrass (Zoysia japonica) are intensively in urban areas in Florida. Fertilization rules in Florida impose restrictive rates, and nitrogen (N) sources to reduce N losses through the soil thought causing non-point source pollution from fertilizers. Limited information is available about N source responses in St. Augustinegrass and zoysiagrass. A field study was established to evaluate the response of 7 N sources including ammonium nitrate (34% N) (AN), urea (46%) (U), sulfur coated urea (30% SCU), sulfur coated urea (50% SCU) (SCUMIX), polymer coated urea (32.8% PCU) (PCUMIX), biosolid (100% natural organic N) (BS) at 49 kg N ha-1 60 d-1, and polymer coated urea (32.8% PCU) at 98 kg N ha-1 120 d-1. Turfgrass quality and color ratings, and chlorophyll index (CI) were evaluated weekly, multispectral reflectance every two weeks, and biomass production once a month from 2008 thru 2010 to determine shoot growth rate, estimation of N content, and Total Kjeldahl Nitrogen in tissue (TKN). Root growth was measured at 2 depths (0-15 and 15-30 cm). Soluble and sulfur coated sources produced higher quality, color, CI, shoot growth rate, higher normalized difference vegetation Index (NDVI), lower Stress indices and higher leaf area index (LAI) than PCUMIX and BS. Polymer coated sources produced and intermediate to long term response. Soluble sources and sulfur coated sources produced higher quality and color in St. Augustinegrass. Otherwise, PCUMIX produced a longer term response and BS did not produce an acceptable quality. All N sources produced good quality and color on zoysiagrass. Zoysiagrass had higher growth rate than St. Augustinegrass. Consequently, higher TKN was obtained with zoysiagrass than St. Augustinegrass. Total Kjeldahl Nitrogen was higher in soluble sources and SCUMIX. Only deficient N values were observed during fertilizer cycle 1 in 2008 from PCUMIX and BS. Total Kjeldahk Nitrogen in tissue increased over the time with no N deficient ranges in any of the N sources. Consequently, CI increase over the time due to the increase in TKN. Root growth was not influenced by N sources. In addition, St. Augustinegrass produced higher root growth at 0 to 15 cm depth, while zoysiagrass produced the highest root length density (RLD). Leaf area index (LAI) was higher in zoysiagrass than St. Augustinegrass due to higher canopy density. The results of this research indicate that soluble sources and SCUMIX produce faster and higher response. Polymer coated urea and BS sources produce long term response. Zoysiagrass produce higher growth parameters than St. Augustinegrass. That is valuable information that describes the responses of the fertilizer in order to evaluate the N source required to reach the turfgrass health and quality required in urban areas in Florida.
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 Ronald Castillo.
Thesis: Thesis (M.S.)--University of Florida, 2011.
Local: Adviser: Trenholm, Laurie E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043880:00001

Permanent Link: http://ufdc.ufl.edu/UFE0043880/00001

Material Information

Title: Effect of Nitrogen Sources on St. Augustinegrass and Zoysiagrass Responses
Physical Description: 1 online resource (140 p.)
Language: english
Creator: Castillo, Ronald
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2011

Subjects

Subjects / Keywords: color -- fertilizer -- quality -- soluble -- turfgrass
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: St. Augustinegrass (Steotaprum secundatum (Walt) Kuntze) and zoysiagrass (Zoysia japonica) are intensively in urban areas in Florida. Fertilization rules in Florida impose restrictive rates, and nitrogen (N) sources to reduce N losses through the soil thought causing non-point source pollution from fertilizers. Limited information is available about N source responses in St. Augustinegrass and zoysiagrass. A field study was established to evaluate the response of 7 N sources including ammonium nitrate (34% N) (AN), urea (46%) (U), sulfur coated urea (30% SCU), sulfur coated urea (50% SCU) (SCUMIX), polymer coated urea (32.8% PCU) (PCUMIX), biosolid (100% natural organic N) (BS) at 49 kg N ha-1 60 d-1, and polymer coated urea (32.8% PCU) at 98 kg N ha-1 120 d-1. Turfgrass quality and color ratings, and chlorophyll index (CI) were evaluated weekly, multispectral reflectance every two weeks, and biomass production once a month from 2008 thru 2010 to determine shoot growth rate, estimation of N content, and Total Kjeldahl Nitrogen in tissue (TKN). Root growth was measured at 2 depths (0-15 and 15-30 cm). Soluble and sulfur coated sources produced higher quality, color, CI, shoot growth rate, higher normalized difference vegetation Index (NDVI), lower Stress indices and higher leaf area index (LAI) than PCUMIX and BS. Polymer coated sources produced and intermediate to long term response. Soluble sources and sulfur coated sources produced higher quality and color in St. Augustinegrass. Otherwise, PCUMIX produced a longer term response and BS did not produce an acceptable quality. All N sources produced good quality and color on zoysiagrass. Zoysiagrass had higher growth rate than St. Augustinegrass. Consequently, higher TKN was obtained with zoysiagrass than St. Augustinegrass. Total Kjeldahl Nitrogen was higher in soluble sources and SCUMIX. Only deficient N values were observed during fertilizer cycle 1 in 2008 from PCUMIX and BS. Total Kjeldahk Nitrogen in tissue increased over the time with no N deficient ranges in any of the N sources. Consequently, CI increase over the time due to the increase in TKN. Root growth was not influenced by N sources. In addition, St. Augustinegrass produced higher root growth at 0 to 15 cm depth, while zoysiagrass produced the highest root length density (RLD). Leaf area index (LAI) was higher in zoysiagrass than St. Augustinegrass due to higher canopy density. The results of this research indicate that soluble sources and SCUMIX produce faster and higher response. Polymer coated urea and BS sources produce long term response. Zoysiagrass produce higher growth parameters than St. Augustinegrass. That is valuable information that describes the responses of the fertilizer in order to evaluate the N source required to reach the turfgrass health and quality required in urban areas in Florida.
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 Ronald Castillo.
Thesis: Thesis (M.S.)--University of Florida, 2011.
Local: Adviser: Trenholm, Laurie E.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2011
System ID: UFE0043880:00001


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1 THE EFFECT OF NITROGEN SOURCES IN ST. AUGUSTINEGRASS AND ZOYSIAGRASS RESPONSES By RONALD JOSUE CASTILLO CHAVES A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREME NTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2011

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2 2011 Ronald Josue Castillo Chaves

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3 To God and my parents

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4 ACKNOWLEDGMENTS I would like to thank my major adviso r, Dr. Laurie Trenholm, for giving me the opportunity in Costa Rica to be her graduate student, and also for her encouragement, am. I am extremely grateful to Dr. Jerry Sartain for his support and constant disposition to help and provide great recommendations an d use of the laboratory under his respons ibility. I am also indebted to Dr. Jason Kruse to allow to use the Turfgrass Envirotron facilities and equipment and also serving in my advisor committee. They were always willing to help along this process. I am al so very grateful with Gerardo Celis and Ronald Gonzalez, who encourage d me to fo llow this process and provide me ideas to success in this research. More tha n that, I would like to thank them for their friendship in all moments. The completion of this resea rch would not be possible without the collaboration of a large group of people that helped me. I am thankful with Ivan Vargas, Antonio Yaquian, Luis Barquin, Basil Wetherington, Tommy Deberry, Joel Cabrera, Enger German, Mark Kann, Brad Williams, Gaby Hern andez, Miguel Castillo, Mauricio Cordero, Carlos Paniagua, Ethel Araya, and Rosa Raudales for their invaluable help and exceptional friendship. I am also very grateful to Maria Four nier, for her extremely support, help, comprehension and love during this process. I am extremely grateful to my parents Ronald Castillo and Jacqueline Chaves to encourage me never giving up and following my dreams with love, honesty, hard work and for their cultivated values on me. Above all, I thank to God for all opportunitie s and blessings to me, which help me to achieve my goals and dreams true.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ ........ 11 ABSTRACT ................................ ................................ ................................ ................... 12 CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW ................................ ..................... 14 Grasses in Our World ................................ ................................ ............................. 14 Economic Impact of the Urban Turfgrass Industry in Florida ................................ .. 15 Benefits of Turfgrasses ................................ ................................ ........................... 16 St. Augustinegrass ................................ ................................ ................................ .. 16 Zoysiagrass ................................ ................................ ................................ ............ 17 Environmental Concern of Water Quality from Turfgrass Systems in Florida ......... 18 Soil Nitrogen Cycle ................................ ................................ ................................ 19 Nitrogen Respons e in Turfgrass ................................ ................................ ............. 20 Nitrogen Fertilization in Warm Season Turfgrasses ................................ ................ 21 Nitrogen Fertilizer Sources Used in Turfgrasses and Their Mode of Action ............ 22 2 MATERIALS AND METHODS ................................ ................................ ................ 28 Location ................................ ................................ ................................ .................. 28 Experi mental Plots ................................ ................................ ................................ .. 28 Fertilizer Treatments ................................ ................................ ............................... 29 Turfgrass Health Evaluations ................................ ................................ .................. 30 Shoot Growth ................................ ................................ ................................ .......... 31 Root Growth ................................ ................................ ................................ ............ 31 Maintenance Practices ................................ ................................ ............................ 32 Experimental Design and Statistical Analysis ................................ ......................... 32 3 EFFECT OF NITROGEN SOURCES ON TURFGRASS QUALITY, COLOR, SHOOT GROWTH RATE, LEAF TIS SUE N CONCENTRATION, NITROGEN CO NTENT AND ROOT GROWTH ................................ ................................ ......... 35 Materials and Methods ................................ ................................ ............................ 38 Location and Experimental Site ................................ ................................ ........ 38 Treatm ents ................................ ................................ ................................ ....... 39 Response Variables ................................ ................................ ......................... 39 Data Presented and Statistical Analysis ................................ ........................... 40 Results and Discussion ................................ ................................ ........................... 41

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6 Visual Quality ................................ ................................ ................................ ... 41 Color ................................ ................................ ................................ ................. 45 Sh oot Growth Rate ................................ ................................ ........................... 50 Nitrogen Content ................................ ................................ .............................. 53 Total Kjeldahl Tissue Nitrogen Concentration in Tissue ................................ ... 56 Root Growth ................................ ................................ ................................ ..... 60 4 EFFECT OF NITROGEN SOURCE ON MULTISPECTRAL REFLECTANCE AND CHLOROPHYLL INDEX IN ST. AUGUSTINEGRASS AND ZOYSIAGRASS ................................ ................................ ................................ ...... 95 Materials and Methods ................................ ................................ ............................ 99 Location and Experimental Site ................................ ................................ ........ 99 Treatments ................................ ................................ ................................ ....... 99 Response Variables ................................ ................................ ......................... 99 Data Presented and Statistical Analysis ................................ ......................... 100 Results and D iscussion ................................ ................................ ......................... 101 Chlorophyll Index ................................ ................................ ............................ 101 Multispectral Reflectance ................................ ................................ ............... 103 Correlation ................................ ................................ ................................ ...... 105 5 SUMMARY AND CONCLUSIONS ................................ ................................ ........ 128 LIST OF REFERENCES ................................ ................................ ............................. 134 BIOGRAPHICAL SKETCH ................................ ................................ .......................... 140

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7 LIST OF TABLES Table page 2 1 Description of treatments, analysis, release characteristic and frequency of applicatio n. ................................ ................................ ................................ ......... 34 3 1 ANOVA table for visual quality. ................................ ................................ .......... 62 3 2 Effect of N sources on visual quality on St. Augustinegrass and zoysiagrass in 2008 and 2010. ................................ ................................ ............................... 63 3 3 Effect of turfgrasses and N sources in visual quality in 2009. ............................. 64 3 4 The response of N sources during th e fertilizer cycles in visual quality in in 2008, and 2009. ................................ ................................ ................................ .. 65 3 5 The response of N sources during the fertilizer cycle (FC) in St. Augustinegrass visual quality in FC2 in 2008 and in FC1, 2, 3, and 4 in 2010. .. 66 3 6 The response of N sources during the fertilizer cycle (FC) in zoysiagrass visual quality in FC2 in 2008 and in FC1, 2, 3, and 4 in 2010. ............................ 67 3 7 ANOVA table for color. ................................ ................................ ....................... 68 3 8 Effect of turfgrasses and N sources on color in 2008 and 2009. ........................ 68 3 9 The effect of N sources on St. Augustinegrass and zoysiagrass color in 2010. 69 3 10 The response of N sources during the fertilizer cycles in color in 2008, 2009, and 2010. ................................ ................................ ................................ ........... 70 3 11 The response of N sources by the fertilizer cycle (FC) in St. Augustinegrass color in FC2, 3, and 4 in 2010. ................................ ................................ ............ 71 3 12 The r esponse of N sources by the fertilizer cycle (FC) in zoysiagrass color in FC2, 3 and 4 in 2010. ................................ ................................ ......................... 72 3 13 ANOVA table for shoot growth rate. ................................ ................................ ... 73 3 14 The effect of turfgrasses on shoot growth rate in 2008, 2009, and 2010. ........... 73 3 15 The effect of N sources on shoot growth rate in 2008, 2009, and 2010. ............ 74 3 16 The effect of turfgrasses and N sources on shoot growth rate by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ ........... 75 3 17 The response of N sources by the fertilizer cycle (FC) in St. Augustinegrass shoot growth rate in FC1, 3, and 4 in 2010. ................................ ........................ 76

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8 3 18 The response of N sources by the fertilizer cycle (FC) in zoysiagrass shoot growth rate in F C1, 3, and 4 in 2010. ................................ ................................ 77 3 19 ANOVA table for nitrogen content. ................................ ................................ ..... 78 3 20 The effect of turfgrasses on nitrogen content in 2008, 2009, and 2010. ............. 78 3 21 The effect of N sources on nitrogen content in 2008, 2009, and 2010. .............. 79 3 22 The effect of turfgrasses a nd N sources on nitrogen content by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ .................... 80 3 23 The response of N sources by the fertilizer cycle (FC) in St. Augustinegrass nitrogen content In FC1, 3, a nd 4 in 2010. ................................ ......................... 81 3 24 The response of N sources by the fertilizer cycle (FC) in zoysiagrass nitrogen content In FC1, 3, and 4 in 2010. ................................ ................................ ....... 82 3 25 ANOVA table for leaf tissue nitrogen concentration. ................................ ........... 83 3 26 The effect of N sources on leaf tissue nitrogen concentration rate in 2008, 2009, and 2010. ................................ ................................ ................................ .. 83 3 27 The effect of turfgrasses and N sources on shoot growth rate by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ ........... 84 3 28 The response of N sources by th e fertilizer cycle (FC) in St. Augustinegrass leaf tissue nitrogen concentration In FC1, 2, and 3 in 2010. ............................... 85 3 29 The response of N sources by the fertilizer cycle (FC) in zoysiagrass leaf ti ssue nitrogen concentration In FC1, 2, and 3 in 2010. ................................ ..... 86 3 30 ANOVA table for root weight, root surface area, and root volume. ..................... 87 3 31 The effect of turfgrasses and sampling date on root weight root surface area and root volume in 2010. ................................ ................................ .................... 87 3 32 ANOVA table for length density. ................................ ................................ ......... 88 3 33 The effect of turfgrasses on root length density in May 12, July 12, and October 12 in 2010. ................................ ................................ ............................ 88 3 34 The effect of N sources and turfgrasses on root weight, root s urface area, root volume, and root length density form 0 to 15 cm depth in May 12, July 12, and October 12 in 2010. ................................ ................................ ............... 89 3 35 The effect of N sources and turfgrasses on root weight, root surface area, root volume, and root length density form 15 to 30 cm depth in May 12, July 12, and October 12 in 2010. ................................ ................................ ............... 90

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9 4 1 ANOVA table for chlorophyll index. ................................ ................................ .. 107 4 2 The effect of turfgrasses on chlorophyll index in 2008, 2009, and 2010. .......... 107 4 3 The effect of N sources on chlorophyll index in 2008, 2009, and 2010. ........... 108 4 4 The effect of turfgrasses and N sources on chlorophyll by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ ...................... 109 4 5 ANOVA table for 450, 550, 660, 694, 710 wavelengths, and NDVI, LAI, stress 1, stress 2 ratios. ................................ ................................ .................... 110 4 6 The effect of turfgrasses on 550, 694 wavelengths and leaf area index ratio in 2008, 2009, and 2010. ................................ ................................ .................. 111 4 7 The effect of N sources on leaf area index in 2008, 2009, and 2010. ............... 112 4 8 The effect of turfgrasses and N sources on normalize d vegetation index by fertilizer cycle in 2008, 2009, and 2010. ................................ ........................... 113 4 9 The effect of turfgrasses and N sources on stress 1 index by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ ...................... 114 4 10 The effect of turfgrasses and N sources on stress 2 index by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ ...................... 115 4 11 The effect of turfgrasse s and N sources on leaf area index by fertilizer cycle in 2008, 2009, and 2010. ................................ ................................ .................. 116 4 12 Pearson correlation matrix of visual quality (VQ), color, and chlorophyll index (CI), with growth rate, nitrogen concentration (TKN), nitrogen content (NC), and reflectance values during the entire research. ................................ ........... 117 4 13 Pearson correlation matrix of growth rate (GR), nitrogen concentration (TKN), and nitrogen content (NC) with visual quality (VQ), color, chlorophyll index (CI), and reflectance values during the entire research. ................................ ... 117 4 14 Pearson correlation matrix of visual quality (VQ) color, and chlorophyll index (CI), with growth rate, nitrogen concentration (TKN), nitrogen content (NC), and reflectance values during the entire research in St. Augustinegrass. ........ 117 4 15 Pe arson correlation matrix of growth rate (GR), nitrogen concentration (TKN), and nitrogen content (NC) with visual quality (VQ), color, chlorophyll index (CI), and reflectance values during the entire research in St. Augustinegrass. 118 4 16 Pearson correlation matrix of visual quality (VQ), color, and chlorophyll index (CI), with growth rate, nitrogen concentration (TKN), nitrogen content (NC), and reflectance values during the entire research in zoysiagrass. ................... 118

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10 4 17 Pearson correlation matrix of growth rate (GR), nitrogen concentration (TKN), and nitrogen content (NC) with visual quality (VQ), color, chlorophyll index (CI), and r eflectance values during the entire research in zoysiagrass. ........... 118

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11 LIST OF FIGURES Figure page 3 1 Average rainfall (mm), maximum and minimum soil t emperature (C) per month in 2008. ................................ ................................ ................................ .... 91 3 2 Average rainfall (mm), maximum and minimum soil temperature (C) per month in 2009. ................................ ................................ ................................ .... 92 3 3 Average rainfall (mm), maximum and minimum soil temperature (C) per month in 2010. ................................ ................................ ................................ .... 93 3 4 Air temperature (C) and solar radiation (w/m2) during 2008, 2009, and 2010. 9 4 4 1 The relationship of evaluation variables. A) Relationship between visual quality and chlorophyll index and B) color and chlorophyll index. ..................... 119 4 2 The relationship of evaluation variables. A) Relationship between chlorophyll index and NDVI, and B) chlorophyll index and LAI. ................................ .......... 120 4 3 The relationship between growth rate and ni trogen content. ............................ 121 4 4 The relationship of evaluation variables. A) Relationship between visual quality and chlorophyll index and B) visual quality and NDVI in St Augustinegrass. ................................ ................................ ................................ 122 4 5 The relationship of evaluation variables. A) Relationship between color and chlorophyll index and B) chlorophyll index and NDVI in St Augustinegrass. .... 123 4 6 The relationship of evaluation variables. A) Relationship between visual quality and LAI and B) color and LAI in St Augustinegrass. ............................. 124 4 7 The relationship of evaluation variables. A) Relationship between chlorophyll index and LAI and B) growth rate and nitrogen content in St. Augustinegrass. 125 4 8 The relationship of evaluation variables. A) Rel ationship between visual quality and growth rate and B) visual quality and nitrogen content in zoysiagrass. ................................ ................................ ................................ ...... 126 4 9 The relationship of evaluation variables. A) Relationship between visual qu ality and chlorophyll index and B) growth rate and nitrogen content in zoysiagrass. ................................ ................................ ................................ ...... 127

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12 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the D egree of Master of Science THE E F FECT OF NITROGEN SOURCES I N ST. AUGUSTINEGRASS AND ZOYSIAGRASS RESPONSES By Ronald Josue Castillo Chaves December 2011 Chair: Laurie E. Trenholm Major: Environmental Horticulture St. Augustinegrass ( Steotaprum secundat um (Walt) Kuntze) and z oysiagrass ( Zoysia japonica ) are intensively in urban areas in Florida. Fertilization rules in Florida impose restrictive rates, and nitrogen (N) sources to reduce N losses through the soil thought causing non point source pollution from fertilizers. Limited informat ion is available about N source responses in St. Augustinegrass a nd zoysiagrass. A field study was established to evaluate the r esponse of 7 N sources including ammonium nitrate (34% N) (AN), urea (46%) (U), s ulfur coated u rea (30% SCU) s ulfur c oated urea (50% SCU) (SCUMIX), p olymer coa ted urea (32.8% PCU) (PCUMIX), biosolid (100% n atural organic N) (BS) at 49 kg N ha 1 60 d 1 and p olymer coated urea (32.8% PCU) at 98 kg N ha 1 120 d 1 Turfgrass quality and color ratings and chlorophyll index (CI) were evaluated weekly, mu ltispectral reflectance every two weeks, and biomass production once a month fr om 2008 thru 2010 to determine shoot gro wth rate, estimation of N content and Total Kjeldahl Nitrogen in tissue (TKN). Roo t growth wa s measured at 2 depths (0 1 5 and 15 30 cm). S oluble and s ulfur coated sources produced higher quality, color, CI, shoot growth rate, higher normalized differen ce vegetation Index (NDVI), lower Stress indices and higher leaf area ind ex (LAI) than PCUMIX and BS. Polymer

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13 coated sources produced and intermediate to long term response. Soluble sources and sulfur coated sources produced higher quality and color in St. Augustinegrass. Otherwise, PCUMIX produced a long er term response and BS did not p rod uce an acceptable quality All N sources produced good quality and color on zoysiagrass. Zoysiagrass had hi gher growth rate than St. Augustinegrass. Consequently higher TKN was obtained with zoysiagrass than St. Augustinegrass. Total Kjeldahl Nitrogen was higher in soluble sources and SCUMIX O nly deficie nt N values were observed during fertilizer cycle 1 in 2008 from P CUMIX and BS. T otal K jeldahk N itrogen in tissue increase d over the time with no N deficient ranges in any of the N sources. Consequently, C I increase over the time due to the increase in TKN Root growth was not influenced by N sources. In addition, St. Augustinegrass produce d higher root growth at 0 to 15 cm depth, while zoysiagrass produced the highest root length density (RLD). L eaf area i ndex (LAI) was higher in zoysiagrass than St. Augustinegrass due to higher canopy density. The results of this research indicate that soluble sources and SCUMIX produce fast er and higher response Polymer coated urea and BS sources produce long term respo nse. Zoysiagrass produce higher growth parameters than St. Augustinegrass. That is valuable information that describes the responses of the fertilizer in order to evaluate the N source required to reach the turfgrass health and quality required in urban ar eas in Florida.

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14 CHAPTER 1 INTRODUCTION AND LIT ERATURE REVIEW Grasses in Our World Grasses are in the family Poaceae and provide both food and forage. Grasses also serve many other purposes, such as construction material as with bamboo ( Bambusa vulgaris Schrad. ex J.C. Wendl. ) and as a biomass grass source to produce methanol and other alternative energy sources (Beard and Green, 1994). Turfgrass benefits are classified as functional, recreational and aesthetic (Beard and Green, 1994). Functional benefit s of turfgrass include protection of natural resources through erosion control, pollution filtration and oxygen production. Pimentel (2000) reported that loss of soil in the United States is estimated to be 6.9 billion of tons each year. Turfgrass is valua ble for reducin g soil erosion risk due to the dense ground cover and high shoot density that ranges from 75 million to more than 20 billion shoots per hectare ( Beard, 1973). Gross et al. (1990 ) reported sediment losses of approximately 10 to 60 kg ha 2 fro m turfgrass plots during a 30 minute storm that produced 76 mm h 1 of rai nfall compared with soil loss f r o m bare soil plots that averaged in 223 kg ha 2 at the same storm rate. The loss of nutrients resulting from soil erosion has an estimated cost of up t o $ 20 billion a year (Troech 1991). Turfgrass provides safe recreational surfaces for sports including soccer, football, golf, baseball, horse racing, tennis, etc. (Beard and Green, 1994). Lawns are an integral part of our environment and enhance any la ndscape (Trenholm and Unruh, 2005). They add value to our homes and provide a safe surface for play and outdoor activities. Lawn grasses may also reduce threats from wildfires. In Florida the most widely used

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15 lawngrass is St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze Zoysiagrass ( Zoysia japonica Steud ) has recently gained in popularity as a lawngrass and is being planted in many home sites statewide. Tre n holm and Unruh (2007) mentioned there are approximately 2 million of hectares of home law n grasses in the state of Florida and almost 40% of them is St. Augustinegrass. Economic Impact of the Urban Turfgrass Industry in Florida Turfgrass is intensively used in many urban areas such as residential lawns, commercial landscapes, and golf courses. Most of the landscape space occupied by turfgrass generates an aesthetic environmental value to urban society. The turfgrass industry also provides an important economic benefit in the United States. In 2002, inputs from the industry across the country we re valued at $57.9 billion dollars and a total employment of 822,849 jobs (Haydu et al. 2006). The turfgrass industry in Florida is the second largest in the United States (Haydu et al. 2006 ), around 1.59 million of hectares are occupied and maintained b y golf courses, sod farms and homeowners (Hodges and Stevens 2010). T hese areas have continued to gr o w rapidly due to increasing demand This accounted for total revenue of $6.26 billion and a total employment of 157,240 jobs (Hodges and Stevens 2010). I n 2007, the landscape turfgrass sector was valued at $2.66 billion representing 44% of the total sales of landscape industry In the same year the landscape industry employed a total of 62,272 people (Hodges and Stevens 2010).

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16 Benefits of Turfgrasses Biomass (leaves, stolons, stems, roots etc.) production by turfgrass provides an excellent resource for trap ping nutrients and other potential pollutants found in storm water runoff, improving water infiltration and filtering through the surface (Bread an d Green, 1994). Studies showed that surface water runoff sediment losses from tobacco ( Nicotiana tabacum L.) was 6.7 mm ha 2 4 wk 1 during the growing season, while runoff sediment losses from t all fescue ( Festuca arundenacia Schreb ) was only 0.6 mm ha 1 4 wk 1 (An gle, 1985; Gross et al., 1990). Nitrogen (N) and phosphorus (P) losses in the same experiment were 0.012 and 0.001 kg ha 1 wk 1 f r o m all fescue as compared to 2.34 and 0.48 kg ha 1 wk 1 from tobacco. Erickson (2001) reported that runoff N losses fr om St. Augustinegrass sod were significantly less than from mixed species landscape plants during the first year after installation. Losses were 48.3 vs. 4.1 kg N ha 1 for mixed landscape plantings and St. Augustinegrass, respectively. S t. Augustinegrass S t. Augu stinegrass is believed native f r o m the Gulf of Mexico and Mediterranean (Trenholm and Unruh, 2005). Other authors mentioned that St. Augustinegrass is native from the West Indies and came to the southern United States during the colonial period (Chr istians, 2007). St. Augustinegrass grows best in well drained soils and can grow in a wide variety of fertility ranges. Desirable features include vigorous growth, good salinity and shade tolerance, and adaptability to a wide range of soil types. Disadva ntages include poor wear tolerance, excessive thatch accumulation, coarse texture, and susceptibility to cold injury and chinch bugs. In Florida, Floratam is

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17 the most widely used cultivar. Floratam was released in 1973 by the University of Florida and Texa s A&M. It has coarse textured leaf blades and possesses poor shade and cold tolerance. Other cultivars with similar characteristics include Bitter Blue, Classic, Sapphire, and Delta Shade. Dwarf or semi dwarf cultivars include Captiva, Delmar, Seville, and Palmetto, poses the best shade tolerance of the species. Nitrogen fertilization requirements range from 49 to 249 kg N ha 1 depending on location (South, Central or North Florida) and desired maintenance level. St. Augustinegrass mowing heights should ran ge from 8.9 to 10.2 cm for the standard type cultivars and 5.1 to 6.4 for the dwarf varieties. Zoysiagrass Zoysiagrass was introduced in the United States from Asia in 1895 (Christians, 2007). Several cultivars are gaining popularity in Florida for use in athletic fields, golf courses and commercial landscapes (Trenholm and Unruh, 2005). Advantages of z oysiagrass include dense growth, a finer leaf texture than many other lawngrass species, and good tolerance to shade, traffic and salt. Disadvantages includ e heavy thatch production, slow growth and spring green up, susceptibility to Rhizoctonia solani Kuhn and nematodes. Varieties tend to form shallow root system s and are weakened when grow n in soils with low potassium levels ( Trenholm and Unruh 2005). Emp ire z oysiagrass is being used increasingly in urban landscapes with mixed results. Nitrogen requirements are less than those of St. August inegrass, ranging from 98 to 196 kg of N ha 1 annually. Mowing height ranges f rom 2.54 cm to 7.62 cm. Empire z oysiagra ss performs well at 7.62 cm mowing height during active growing (Unruh et al., 2007).

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18 Environme ntal Concern of Water Quality from Turfgrass Systems in Florida Water is the main resource needed to sustain life on earth. Approximately 97% of fresh water use d for human consum ption is ground water, (Hornsby et al. 1999). Approximately 10% of the turfgrass managed in the US is under relatively high management including fertilization and irrigation ( Beard and Green, 1994). In Florida, approximately 1.95 millio n of hectares of turfgrass (Hodges and Stevens 2010) is maintained, which represents 11.5% of the total area of Florida. If management practices related to fertilization and irrigation are done improperly, the result could be nutrient movement of N or pho sphorus (P) as leachate or runoff that could potentially pollut e ground and or surface waters. Eutrophication of water bodies can result due to oxygen depletion and algae blooms. Eutrophication can occur at P l evels of 0.01 to 0.035 mg L 1 (Mallin and Wheel er, 2000) T he United States Environmental Protection Agency (EPA) limit for nitrate N ( NO 3 N ) in drinking water is 10 mg L 1 which sometimes is exceeded by 100 150% (Saha, 2004). When consumed, high concentrations of NO 3 N can produce methemoglobin a to xic compound resulting from the combination of nitrite ( NO 2 N) with hemoglobin. This results in a lack of blood to carry oxygen and result in serious health concerns (Liyanage et al 2000). Some advocate that turfgrass systems in urban environments are pr incipal contributor s of non point source pollution a lthough no scientific evidence relates N practices in urban landscape with nutrient pollution ( Flipse et al. 1984). Local ordinances in Florida ha ve been imposed to reduce potential nonpoint source poll ution potentially resulting from fertilization of turfgrass in landscape. Best Management Green Industries were established in 2002 through the

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19 Florida Department of Environmental Protection (FDEP) and the University of Florid a Institute of Food and Agricultural Sciences (IFAS). The ensuing educational program is pesticide safety to reduce potential nonpoint source pollution. Numerous city and cou nty governments in the state, as well as a newly enacted state statute, require that all et al., 2008 ). Lawn fertilization re commendations in Florida ha ve been changed in order to reduce potential N impact on ground water resources. Since December 31, 2007 every one who fertilizes a home lawn must comply with a new state rule (Department of Agriculture and Consumer Services (DAC S), No 4640400, Rule 5E 1.003, 2007 ) The rule regulates N application rates. S low release nitrogen can be applied at a maximum of 49 kg of N ha 1 per application, while soluble nitrogen can be applied at a maximum rate of 34.3 kg ha 1 per application (De partment of Agriculture and Consumer Services (DACS), No 4640400, Rule 5E 1.003, 2007). Soil Nitrogen Cycle The content of N in soils ranges from 0 (clean sands) to 2.5% (organic soils). Nitrogen is absorbed by turfgrass as nitrate or ammonium. Through th e process of mineralization, organic nitrogen (organic matter) is converted into available N forms for plants. The process of mineralization involves two steps: ammonification and nitrification. Ammonification is the process where organic matter is convert ed to ammonia (NH + 3 ) and then ammonium (NH + 4 ) (Carrow et al., 2001). The ammonium could be nitrified to nitrate, taken up by the plant, attracted to cation exchange sites, fixed in the clay minerals or lost via volatilization or leaching. Nitrification is the

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20 conversion of ammonium to nitrite by the Nitrosomonas and Nitrospora bacteria and then into nitrate by the nitrobacter bacteria. At this point, the nitrate can b e taken up by the plant, lost through denitrification as N 2 O or leached through the soil. M ineralization of nitrogen is influenced by microbial activity, which is affected by environmental conditions such as soil temperature, moisture, oxygen, and pH. Optimal temperature for microbial activation for nitrification range from 30 to 35 C, with a m inimum soil temperature of 15 to 17 C. There must also be adequate soil moisture for mineralization to occur. Nitrification declines at pH levels lower than 5.5 (Carrow et al 2001). Nitrogen R esponse in Turfgrass Nitrogen (N) is the nutrient required in greatest quantities by turfgrass, promoting vigor, quality, shoot density and color (Bowman et al. 2002). Functions of N are widely described as having both a structural and functional component. As N is taken up by plant it is assimilated into amino aci d s that provide the basis of formation of N compounds. These amino acids serve as precursors for proteins, chlorophyll, enzyme, hormones, osmoregulators and nucleic acids (Carrow et al. 2001) Turf grass responses to nitrogen are increased green color, s hoot growth, shoot density, and root growth Moderate rates of N can increase carbohydrate reserves thatch accumulation and recuperative potential as well as improve many stress tolerance s such high temperature stress, cold tolerance, drought resistance, compaction and wear tolerance (Carrow et al. 2001). However, excess N can reduce carbohydrate reserves and stress tolerance and can also lead to increased disease and potentially insect outbreaks.

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21 Nitrogen Fertilization in Warm Season Turfgrass es Nitroge n deficiencies in turfgrass are visually detected by loss of green color (chlorosis) that appears first in older leaves. Newer leaves remain green until the plant is able to convert N compounds to a soluble form and translocate it to new leaves (Carrow et al. 2001). Additional symptoms of N deficiency include lack of growth, loss of leaves, tillers, and thinning of turf (Carrow et al. 2001). Nitrogen requirements depend on the species, growth season and use regime. Warm season turfgrass receiving appropri ate N fertilization will typically have between 2.75 to 3.75 % total N con tent (TKN) in leaf tissue (Carrow, 2001). Sufficien cy ranges of N in St. Augustinegrass and z oysiagrass in leaf tissue have been identified as ranging from 1.90 to 2 17 % ( Christians 2007) or 2.00 to 3.00 % (Sartain, 2001). Trenholm (2007) suggest that N applications to St. Augustinegrass range from 98 to 249 kg of N ha 2 year 1 Recommended z oysiagrass range is from 147 to 245 kg of N ha 2 year 1 but these researchers have demonstr ated that the cultivar Empire can perform optimally with 98 to 196 kg N ha 2 yr 1 Fertilization timing in warm season turfgrass should correspond to the growth pattern and N needs during the year, with greatest needs during the summer months when growth i s greatest. Application of N prior to start of active growth can be problematic through depletion of carbohydrates needed for spring green up and the potential for winter damage to succulent new tissue resulting from N application. Fertilization is likewis e not recommended after the growing season has ende d in central and north Florida, whic h occurs from October to March.

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22 Nitrogen Fertilizer Sources U sed in Turfgrasses and T heir Mode of A ction Nitrogen may be applied from numerous sources, which are classif ied as quick release ( water soluble ) controlled release, slow release, or organic N Florida soils typically have a limited ability to retain N and therefore require regular additions for maintenance of a healthy turfgrass (Sartain and Kruse 2001). Quick release sources indicate rapid availability of N after application. Primary quick release sources are ammonium sulfate, ammonium nitrate and ure a. Ammonium sulfate (AS) is a white crystalline material containing 20 21% N and 24 % S. Solubility is somewhat lower than other quick release sources (Sartain, 2009) It has low hygroscopicity and contains N and sulfur. Nitrification of ammonium sulfate produ ces acidity in the soil, mak ing it the preferred N source for alkaline soils (Sartain and Kruse 2001). It produces a dark green color in turfgrass due to increasing the availability of Iron (Fe) and Manganese (Mn). It is subject to volatilization if not water ed in shortly after application (Sartain, 2009). Ammonium nitrate (AN) is 33 34% N and is readily solub le It has high hygroscopicity, a risk of explosion when combined with fuel and is considered more prone to leaching and denitrification (Havlin et al 2005). It is subject to volatilization if not watered in shortly after application. Urea (U) is 45 46% N and has a relatively low salt index of 1.62. Application without watering in may burn turfgrass (Sartain, 2009). Urea is a non ionic compound when placed into the soil solution and may leach rapidly through the soil profile if not taken up by the root s ystem. Urea requires the enzyme urease for conversion to NH + 4 It is subject to volatilization if not watered in shortly after application.

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23 Control led release and slow release nitrogen refers to timed release or reduced so lubility. These products release N into the soil solution at rates or amounts that permit maximum uptake and use efficiency of applied nutrient (Sartain, 2009). They have lower potential to cause injury from fertilizer burn, can be applied at higher N rates, and require fewer applications than quick release N sources. Disadvantages include the slow response applications and higher cost than quick release sources. A coated fertilizer is a term used to characterized fertilizer materials with a core covered with a water insoluble coating (Sart ain, 2009). The coating makes a physical barrier that limits or controls the rate of water penetration into the fertilizer granule. These products may use different multilayer coats including sulfur and polymer. Sartain and Kruse (2001) described sulfur c oated urea (SCU) as containing from 32 to 38 % N. The mechanism of SCU release is by water penetration through microspores and imperfections. The release depends o n thickness of sulfur coating, biological activity through degradation of the sulfur coating soil pH moisture and temperature. Turfgrass responses to these materials may last from 6 to 16 weeks (Sartain, 200 9). Polymer coated urea fertilizers (PCU) contain around 40% of N (Sartain and Kruse, 2001). Carrow et al. (2001) describes the mechanism of release as due to osmotic diffusion. The coating acts as a semi permeable membrane through which water m oves to dilute the urea g ranule and then it diffuse it. Diffusion depends on coating thickness, diffusion rate and temperature. Natural organic nitroge n sources are characterized by a low N content, which vary among the different sources (Carrow et al. 2001). Materials commonly used to develop

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24 these fertilizers are hoof and horn meal, fish scrap and meal, dried and composted manure, composted poultry wa ste, and sewage sludge (Carrow, 2001). Release of N depends of several factors including the carbon to nitrogen ratio, microbial activity, temperature, soil moisture, oxygen, and soil pH. They have a low burn potential and provide a slow release of N over a long period of time (Christians, 2007). Fate of Nitrogen Applied to Turfgrass Nitrogen not taken up by turf has the potential to leach through the soil profile as NO 3 N, as it is not held in the negatively charged soils. In Florida, soil characteristics including high water table, low cation exchange capacity (CEC), high infiltration rates and poor water holding capa city make them vulnerable to nitrate (NO 3 N) leaching Other factors affecting NO 3 N leaching include irrigation management, degree of turfg rass establishment, species, N rates, application timing and N sources (Bowman et al. 2002). I rrigation applied at rates exceeding evapotranspiration has been shown to increase NO 3 leaching from Kentucky bluegrass ( Poa pratensis L.) (Morton et al. 1988) Snyder et al. (1984) found that daily irriga tion of hybrid b ermudagrass ( Cynodon dactylon x C. transvaalensis Burt Davy) resulted in N losses from 22% to 56% of total N applied. In contrast, Bowman et al. (1998) reported N losses of less than 1% by sched ule d irrigation based on soil moisture determin ed by tensiometers. Turfgrass establishment method also affected N loss. Leachate concentration was greater from Kentucky bluegrass that had been seeded (15.89 mg L 1 ) than that which was sodded (9.52 mg L 1 ) in the first two months due to time of seed emergence and root growth development (Geron et al., 1993). As the turfgrass matured, concentrations

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25 were reduced to 1 mg L 1 and 5.3 mg L 1 of NO 3 N from seeding and sodding, respectively. The authors cited roo t development as the reason for reduction in NO 3 N leachate concentration (Geron et al. 1993). Some researchers believe that established mixed species in a landscape such ornamental plant and turf may reduce N leaching. Ericskon et al (2001) reported tha t N losses from ornamental plants through leaching were 48.3 Kg N ha 1 compared with 4.1 kg N ha 1 yr 1 f rom St Augustinegrass fertilized with 300 kg of N ha 1 Nitrogen leaching was low through the year and only increase during excessive rainfall events. During summer months NO 3 is absorbed efficie ntly and little leaching occur. Erickson concludes that St. Augustinegrass were more efficient by storage of N in the turf form thatch soil. Also, there is a high shoot and root density in St. Augustinegrass whe n compared to ornamental plants Genotype characteristics of turfgrass varieties have a fundamental role on nitrogen uptake capacity. Carrow (1989) mentioned that St. Augustinegrass has a high genetic potential for rooting depth, which could provide better nutrient uptake. St. Augustinegrass produced more root volume, root length density and dry weight when compared to Empire z oysiagrass in the first 30 cm (Fuentealba, 2010). Also, Fuentealb a (2010) mentioned that Empire z oysiagrass has been shown to prod uce fewer roots at lower depths (>30 cm) than St. Augustinegrass, and the rate root development for St. Augustinegrass was sig nificantly greater than Empire z oysiagrass at 2.71 cm day 1 and 1.77 cm day 1 respectively. However, l ess N is needed in Empire z oysiagrass to maintain healthy turf. In a lysimeter greenhouse study, Bowman et al. (2002) reported that Floratam had the least NO 3 N leaching compared with c entipedegrass, Meyer zoy s iagrass, Emerald z oysi a grass,

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26 hybrid bermudagrass and common b ermudagrass Greatest leaching losses were from Meyer z oysiagrass Greatest losses occurred from the first application, when from 48% to 100% of NO 3 N and 4 to 16% of the NH 4 N applied was leached. In subsequent applications, leaching losses were reduced. Nitrogen re co very was 63 and 84% from Meyer z oysiagrass and St. Augustinegrass, respectively. G reater root length density in Floratam St. Augustinegrass below 30 cm depth was attributed to reduc ing NO 3 N leaching losses. Some authors have determined that N source ca n also affect NO 3 N leaching. Brown et al. (1997) found that soluble sources such as ammonium nitrate (NH 4 NO 3 ) produced substantially higher NO 3 N concentration in leachate. Soluble sources solubilize N more rapidly and move into the soil profile instantly Those characteristics may increase the potential losses if fertilizer is over applied or turf cover or density is poor. Brown et al. (1981) tested the NO 3 N losses from various N sources on a sandy soil media. Soluble sources such as ammonium n itrate had highest NO 3 N losses. Highest total N losses were 23 % of the total N applied. Nitrate concentration in leachate from NH 4 NO 3 was 170 mg L 1 at 15 to 35 days after application. Leachate from 12 12 12 resulted in 10 mg L 1 from 5 to 20 days only. Losses fro m IBDU did not exceed 10 mg L 1 and NO 3 concentration from Milorganite was very small. Highest total N losses were 23 % of the total N applied from NH 4 NO 3 Use of controlled release fertilizers applied over a high root mass turf genotype reduced fertiliz er loss i n drainage water (Kilian et al. 1961). In contrast, Quiroga et al. (2001) found that proper ly timing application during the growing season and proper irrigation practices limited N losses for soluble sources. Sartain (2008) demonstrated

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27 that resid ential turfgrass can accumulate at least 4.9 g m 2 N applied from soluble sources with no appreciable NO 3 N leaching. Petrovic (2004) reported less NO 3 N concentrations leached from slow release N sources applied to Kentucky bluegrass (0 12 % on N applied) In contrast, Erickson et al. (2008 ) observed no differences on N concentration on leaching from St. Augustinegrass in South Florida. T here is a lack of knowledge comparing the effect of nitrogen sources effect on leaching and turf health on wa rm season turfgrasses. Hence, the main objective of this project was to compare the effect of N source on NO 3 N leaching (data not presented) and turfgrass responses from Floratam St. Augustinegrass and Empire z oysiagrass.

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28 CHAPTER 2 MATERIALS AND METHOD S Location The research was conducted at the G.C. Horn Turfgrass Research Facility at the Plant Science Research and Education Unit Citra, FL. from July 2008 through November 2010 Turfgrasses evaluated were Floratam St. Augustinegrass and Empire z oysiagrass, both o f which were established as sod in 2005. The soil type was Tavares sand (Hyperthermic Uncoated Typic Quartzipsamments), with a pH of 6.8 and organic matter content of 1.3 % Experimental Plots Experimental plots measured 4.0 m x 4.0 m High density polyeth ylene (HDPE) drainage lysimeters were installed in the center of each plot, with the top approximately 10 cm below the soil surface. The lysimeter was concave with a diameter of 57 cm by 88 cm in height with a total volume of 168 L Lysimeters were assembl ed by placing cylinders into a single piece galvanized steel base unit measuring 25.4 cm in height. Gravel was placed in the bottom of each lysimeter for a volume of 38 L. Gravel was covered with fitted non woven polyolefin cloth that was secured with a ho op of 1.3 cm HDPE tubing to reduce soil intrusion into the reservoir. Soil was replaced into the lysimeters as it had been removed from the soil profile. Soil was gently tamped with a tamping tool (17 kg and 858 cm 2 ) to approximate original soil bulk densi ty which was checked before A bulkhead fitting was inserted into the base of each unit, to which collection tubing (0.95 cm low density polyethylene) was attached. The tubing was run underground to central aboveground collection portals and connected in a PVC tower and organized i n numerical order inside box.

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29 Fertilizer Treatments Six of the 8 N treatments were applied at a rate of 49.0 kg N ha 1 in equally split applications throughout the growing season. Treatments are listed in Table 1. In 2008, trea tments were applied on 24 July and 24 September. In 2009, treatments were applied on 17 April, 17 June, 17 August and 17 October. In 2010, treatments were applied on 21 April 21 J une, 20 July and 19 October. Granular N was applied by hand in two direction s to each plot to assu re uniform cover age of the fertilizer. Irrigation was applied at a rate of 6.4 mm immediately af ter every application to solubilize the fertilizers and transport them into the root zone. Leachate samples were collected on a weekly bas is. In 2008, sampling events started on 17 July (base line) and continued through 27 October. In 2009, sampling events resumed on 18 January and continued through the end of the year. Samples were collected by applying a vacuum to the collection tubing wit h a vacuum pump (Gardner Denver Welch Vacuum Technologies, Inc. Skokie, IL) and withdrawing percolate from the reservoir of the lysimeter until dry. Vacuum pressure was maintained at approximately 69.6 cm Hg. Leachate volume was recorded and a sample of 20 mL was collected for analysis of NO 3 N concentration. The sample was acidified with 1 mL of sulfuric acid (H 2 SO 4 ) (conc. 93.6%) to prevent denitrifica tion and placed in a cooler at a temperature of 0C. Sample s were collected 1 minute after leachate start ed to release from the lysimeter to obtain a homogeneous sample of the total volume. Any concentrations that were lower than the minimum detection limit (MDL) of 0.05 mg L 1 were corrected to the MDL value. Time of sample collection was recorded. The pH of the sample was tested in the field with a pH paper tester In addition to plot samples, 5 duplicates, 2 field blanks and

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30 2 equipment blanks were also collected at each sampling ev ent. After every sampling event equipment was cleaned and washed 3 times wit h distilled water to avoid contamination. Nitrate concentration was measured using an Auto Analyzer 3 continuous segmented flow analyzer (Seal Analytical, Mequon, WI) at the University of Florida Analytical Research Laboratory in Gainesville. Results are p resented as NO3 N concentration (mg L 1 ) and total nitrate N loading (TN L ) as kg NO 3 N ha 2 Total nitrate N loading was determined by the following formula: TNL = (Nitrate N concentration (mg L 1 ) x Total leachate volume (L) )/ unit area of the lysimeters). Turfgrass Health Evaluations All turfgrass visual eva luations were made every twice a month In 2008, evaluations were conducted from 29 July through 17 October. In 2009, evaluations were conducted from 6 March thru 26 November and in 2010 evaluations wer e conducted from 3 March thru 13 November. Turfgrass quality ratings were measured on a scale from 1 9, where 1= dead, brown turf and 9= optimal, green turf. Acceptable turfgrass quality was considered 5.5 Color ratings were measured with the same scale, with 1 representing completely chlorotic turf and 9 representing a deep green color Acce ptable turfgrass color was 5.5. A chlorophyll meter (CM 1000) (Spectrum Technologies, Inc., Plainfield, IL) was used to determine an estimate of chlorophyll as determ ined by a ratio of reflectance. Multispectral reflectance readings (MSR) were measured once a month during the experiment with a Cropscan model MSR 16 radiometer (CROPSCAN, Inc., Rochester, MN). R eflectance was measured at wave lengths of 450, 550, 660, 694 710, 760, 835, and 930 nm. In addition, the following growth and stress indices were evaluated:

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31 NDVI (normalized difference vegetation index) growth index computed as ( R 930 R 660 ) / ( R 930 + R 660 ). Best= 1.0. IR/R (leaf area index) growth index computed as R 930 / R 660 Best= highest value. Stress1 index computed as R 710 / R 760 Best= lowest value. Stress 2 index computed as R 710 / R 810 Best= lowest value. Shoot Growth Clippings were harvested two weeks after each treatment application. In 2008, harvest dates were 7 August, 8 October, and 30 October (terminal harvest). In 2009, harvests occurred on 5 May, 5 June 9 September 29 October and 26 November (terminal harvest). In 2010, harvest dates were 1 May, 10 June, 8 July, 11 August, 3 September, 13 October an d 3 November. Clippings were collected with a Honda walk behind mower with a back bag collector Mowing area was 0.306 m x 3.65 m Mowing height was 10.2 and 7.65 cm for St. Augustinegrass and Zoysiagrass respectively. The samples were dried in an oven f or 48 hours at 75 0 C and weighed. The dry tissue was ground and nitrogen concentration was determined as Total Kjeldahl Nitrogen (TKN). Root Growth Root harvest collections were made by taking three soil core s. In 2008 and 2009, cores were taken at 0 15 cm depth from each plot. The area of the core was 6.01 cm 2 In 2008, cores were taken on 30 October and in 2009 on 23 November. In 2010, coring dates were 12 May, 12 July and 12 October. Samples were collected from two depths: 0 15 cm and 15 30 cm. Samples were washed free of soil scanned with a root scanner a nd analyzed by the software WinRizho (WinR hizo, Regent Instruments Quebec, Canada) to obtain variables of total root volume surface area and length and root

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32 length density S amples were then dried fo r 72 hours at 75 C and w eighed for a total dry weight. Maintenance Practices Turfgrass was mowed weekly throughout the study period with a Honda 54 cm w alk b ehind m ower. Clippings were returned to the ground. Height of cut (HOC) was 10.2 and 7.65 cm on Floratam St. Augustineg rass and Empire z oysiagrass, respectively Irrigation was applied at 2.55 cm weekly, or as needed, depending on weather conditions. Nemacur 10% (Ethyl 3methyl 4(methylthio)phenyl(1 methylethyl) phospharamidate was applied in April 20 08 to control nematodes in Zoysiagrass plots. Barricade 65GW (Prodiamine 65%) was applied as a pre emergence herbicide to control grassy weeds and broadleaves in September 2008 and 2009. Image 70DG (Imazquin) was applied in March 2009 and 2010 for control of grassy weed s, sedges and broadleaves Plots were verticut i n late M arch 2009 and 2010 to reduce thatch build up. Experimental Design and Statistical Analysis The experi mental design was a split plot with four replications t urfgrass species as whole pl ots and N treatments as sub plots Data were analyzed with the SAS analytical program (SAS institute, Inc. 2009). Analys e s of Variance (ANOVA) were performed to determine the significance of the variables at the 0.05 significance level. M eans were separat ed using single degree of freedom contrast analysis. The model for this experiment was: y ijkl = + b i k + w ij l kl + e ijkl

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33 y ijkl : is the response for treatment combination kl located in block I and whole plot ij : is the overall mean. b i : is the fixed effect of block i i m k : is the effect of treatment level k of the whole plot factor, k t 1 w ij : is the random effect associated with whole plot j located in block i j t 1 l : is the effect of treatment level l of the subplot factor, l t 1. kl : is the effect of interaction between treatment levels k and l e ijkl : is the devi ation reflecting variation about the population values. e ijkl b i b 2 ]

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34 Table 2 1. Description of treatments, analysis, release characteristic and frequency of application. Treatment Analysis Release Characteri stic Application Rate (kg ha 1 ) Frequency of application (days) Control Ammonium Nitrate (AN) 34 0 0 Soluble 49 60 Urea (U) 46 0 0 Soluble 49 60 Sulfur Coated Urea (SCU) 16 0 8 30% Sulfur coated 49 60 Sulfur Coated Urea (SCU) 19 0 19 50% Sulfur coated 49 60 Polymer Coated Urea (PCU) 41 0 0 32.8% Polymer coated 49 60 Polymer Coated Urea (PCU) 41 0 0 32.8% Polymer coated 98 120 Biosolid (Natural Organic Nitrogen) (NON) 6 2 0 100% Natural organic nitrogen 49 60

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35 CHAPTER 3 EFFECT OF NITROGEN SOURCES ON TURFGRASS QUALITY COLOR, SHOOT GROWTH RATE, LEAF TI SSUE N CONCENTRATION, NIT ROGEN CONTENT AND ROOT GROWTH Nitrogen (N) is an essential element in a turfgrass fertilization program. Adequate N is required to maintain acceptable aesth etic appearance, shoot growth, sufficient N leaf concentration and a healthy root system. Nitrogen deficiencies in turfgrass are visually detected b y loss of green color (chlorosis ) that appe ars first in older leaves. Older leaves remain green until the pl ant is able to convert N compounds to a soluble form and translocate it to new leaves (Carrow et al. 2001). Additional symptoms of N deficiency include lack of growth, loss of leaves and tillers, and thinning of turf (Carrow et al. 2001). Nitrogen may be applied from numerous sources, which are classified as quick release ( water soluble ) controlled release, slow release, or organic N Florida soils typically have a limited ability to retain N and therefore require regular additions of N for maintenance o f a healthy turfgrass (Sartain and Kruse 2001). Previous research has investigated the effect of N sources on tu rfgrass quality. Trenholm and Unruh (2004) tested high and low rates of N over bermudagrass cultivars Tifsport and Tifdwarf. The authors conc luded that higher N rates (514 kg ha 1 yr 1 ) produced better visual quality responses, regardless of the N sources. Floratam St. Augustinegrass was also tested and had no differences in quality from N at rates of either 98 or 196 kg ha 1 yr 1 Sartain (199 2) evaluated different N sources on bermudagrass. Sources tested included milorganite and other natural organic slow release N from sources such as hydrolyzed poultry feather meal, blood meal, soybean meal and bone meal. Also tested were ureaform and water soluble urea and ammonium sulfate. The natural organic

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36 products produced greater growth rate responses compared with milorganite and ureaform. The author also reported highest quality was obtained from natural organic sources based on hydrolyzed poultry f eather meal, blood meal soybean meal, and bone meal). Hummel and W a ddington (1981) evaluated several N sources on Kentucky bluegrass (Poa pratensis L.). The N sources were sulfur coated urea, isubutylidene diurea (IBDU), ureaformaldehyde, activated sewage sludge, organiform, and ammonium sulfate. Results indicated that sulfur coated urea had more uniform growth compared to IBDU, which produced slower growth responses. Turfgrass quality was reduced with ureaform, organiform and sewage sludge. Lower values of N recovery were obtained (from 15 to 29%) with ureaform, organiform, and sewage sludge. Recovery of N in clippings was higher from ammonium sulfate and sulfur coated urea (48 and 52%, respectively). Sartain (2008) tested the effect of N sources and rates on St. Augustinegrass. Materials evaluated were soluble urea and a combination of urea and ammonium nitrate. Soluble sources were applied at 4.88 g m 2 every 30 days. Controlled release sources evaluated were sulfur coated urea (SCU) applied at 4.88 g N m 2 every 60 days and a polymer coated urea with 6 month release properties that was applied at 12.26, 9.76 and 7.32 g N m 2 Results showed that visual quality was maintained through the study with a rating of 6 or better. Urea and control release (polymer coated) applied at 12.26 g N m 2 obtained significant higher visual quality than urea ammonium nitrate, sulfur coated urea, and control release source applied at 7.32 g N m 2

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37 Maintaining adequate N tissue concentration is critical for sustaining turfgra ss health. Quiroga et al. (2001) concluded that N concentration in bermudagrass clippings were lower from hydrofor m slow release N, which supplied 43.6 g N kg 1 compared with sulfur coated urea and wa ter soluble urea, which supplied 51.6 and 50.5 g N kg 1 respectively. Sartain (2008) found that tissue levels in St. Augustinegrass in response to soluble N sources were in a sufficient range of 20 g N kg 1 In contrast, turfgrass that received controlled release N were below the recommended 20 g N kg 1 concent ration and would be cons idered deficient in tissue N. There is little information about the effect of N sources on turfgrass root growth. Horst et al. (1985) reported that the addition of calcium to urea or nitrate N increased both bermuda grass quality and root growth. Some research has reported on differences in rooting between wa rm season turfgrass species. Bowman et al. (2002) reported that St Augustinegrass had higher root length density than Meyer zoysiagrass in a greenhouse study comparing nitrate N leaching from multiple warm season turfgrass species. This resulted in less nitrate N leached from St. Augustinegrass than from Meyer zoysiagrass. Fuentealba (2010) noted that Empire zoysiagrass produced fewer roots at lower depths (>30 cm) than St. August inegrass and that the rate of root development for St. Augustinegrass w as greater than for Empire zoysiagrass (2.71 and 1.77 cm day 1 respectively). There is little information on the effect of N source on nitrate N leaching from warm season turfgrass spe cies. Hence the following hypotheses were formulated for this experiment: Soluble nitrogen sources will provide faster color and quality responses than control led release and organic sources in St. Augustinegrass and z oysiagrass.

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38 Nitrogen leaf tissue con tent, growth rate, and N uptake will be higher with soluble sources. Polymer coated sources will provide a long to intermediate response in variables such visual quality, color, growth rate, N uptake, and N tissue concentration. St. Augustinegrass will pro duce a higher shoot growth rate, root dry weigh t root volume root surface area, and root length density than zoysiagrass. To answer the hypothesis formulated the research objectives of this study were: 1. To evaluate the response of various N sources on acc eptable visual turfgrass quality and color. 2. T o compare the effect of various N sources on shoot growth N uptake and N tissue concentration with sulfur coated sources, polymer coated sources and organic N. 3. To evaluate differences between the two grasses fo r shoot growth rate, root dry matter root volume, root surface area and root length density. 4. To determinate the effect of nitrogen sources on root dry matter, root volume, root surface area, and root length density. Materials and Methods Location and Exp erimental Site The research was conducted at the G.C. Horn Turfgrass Research Facility at the Plant Science Research and Education Unit Citra, FL. from July 2008 through November 2010 Turfgrasses evaluated were Floratam St. Augustinegrass and Empire z o ysiagrass, both of which were established as sod in 2005. The soil type was Tavares sand (Hyperthermic Uncoated Typic Quartzipsamments), with a pH of 6.8 and organic matter content of 1.3 % Exper imental plots measured 4.0 m x 4 .0 m

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39 Treatments Treatment s are listed in Table 1. Six of the 8 N treatments were applied at a rate of 49.0 kg N ha 1 in 4 equally split applications throughout the growing season. One of the treatments was applied at a rate of 98.0 kg ha 1 twice a year. In 2008, treatments were ap plied on 24 July and 24 September. In 2009, treatments were applied on 17 April, 17 June, 17 August and 17 October. In 2010, treatments were applied on 21 April 21 J une, 20 July and 19 October. Granular N was applied by hand in two directions to each plot to assure uniform plot coverage. Irrigation was applied at a rate of 6.4 mm immediately after every treatment application Response Variables Turfgrass quality ratings were measured on a scale from 1 9, where 1= dead, brown turf and 9= optimal, green turf Acceptable turfgrass quality was considered 5.5 Color ratings were measured with the same scale, with 1 representing completely chlorotic turf and 9 representing a deep green color Acceptable turfgrass color was 5.5 (Morris and Shearman 2011). All tu rfgrass visual evaluations were made on a biweekly basis. In 2008, evaluations were conducted from 29 July through 17 October. In 2009, evaluations were conducted from 6 March thru 26 November and in 2010 evaluations were conducted from 3 March thru 13 Nov ember. Clippings were harvested two weeks after each treatment application. In 2008, harvest dates were 7 August, 8 October, and 30 October (terminal harvest). In 2009, harvests occurred on 5 May, 5 June 9 September 29 October and 26 November (terminal harvest). In 2010 harvest dates were 1 May, 10 June, 8 July, 11 August, 3 September, 13 October and 3 November. Clippings were collected with a Honda walk behind mower with a back bag collector Mowing area was 0.306 m x 3.65 m Mowing

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40 height was 10.2 an d 7.65 cm for St. Augustinegrass and z oysiagrass respectively. The samples were dried in an oven for 48 hours at 75 0 C and weighed. The dry tissue was ground and nitrogen concentration was determined as Total Kjeldahl Nitrogen (TKN). Also TKN were multip lied by the growth biomass and divided by the mowing frequency of 7 days to obtain an estimate of N uptake from clippings. Root harvest collections were made by taking three soil core s. In 2008 and 2009, cores were taken at 0 15 cm depth from each plot. Th e area of the core was 6.01 cm 2 In 2008, cores were taken on 30 October and in 2009 on 23 November. In 2010, coring dates were 12 May, 12 July and 12 October. Samples were collected at 0 15 cm and 15 30 cm. Samples were washed free of soil scanned with a root scanner and analyze d by the software Winrizho (WinR hizo, Regent Instruments Quebec, Canada) to obtain variables of total root volume surface area and length and root length density S amples were then dried for 72 hours at 75 C and weighed for a to tal dry weight. Data P resented and Statistical Analysis Data are presented by Fertilizer Cycle (FC), which is defined as the period of approximately 60 days between each fertilizer application and as annual averages or totals. In 2008, there were two FCs since the research began in mid season that year. In 2009 and 2010, there were 4 FCs. Nitrogen sources were grouped by release characteristics for analysis. Groups were: SCUMIX (SCU1 and SCU2), PCUMIX (PCU1 and PCU2). The experimental design was a split plot design with four replications with turfgrass species as whole plots and N treatments as sub plots Data were analyzed with the mixed model procedure (Proc MIXED ) of the SAS analytical program (SAS I nstitute Inc ., 2009). Repeated measures were used t o obtain results for visual quality,

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41 color, shoot growth rate, leaf tissue N concentration and N uptake and root growth. Analys i s of Variance (ANOVA) determine d differences at the 0.05 significance level. Means were separated using contrast analysis. Resu lts and Discussion Visual Quality Visual quality was affected by the in teraction of N source, grass and year ( T able 3 1). In 2008, quality differed due to the interaction of N source and grass (Table 3 2). Averaged over all dates in 2008, St. Augustinegras s visual quality was above acceptable, with the exception of plots that received SCU2. Averaged over the growing season, z oysiagrass quality scores in 2008 were above the acceptable level of 5.5. Contras t analysis showed no difference between N sources, in cluding the control. Contrast analysis showed no differences in turf quality between N sources in either grass (Table 3 2) Acceptable responses in control plots may be residual effects of 3 years of previous research imposed on these plots. In 2008, diffe rences occurred due to grass in FC1, with higher quality scores in zoysiagrass (Table 3 4). An interaction N source and grass occurred in FC2 in 2008. There were no differences St. Augustinegrass and zoysiagrass due to N source in FC2 for 2008. (Table 3 5 and 3 6) In 2009, differences occurred due to main effects of N source and grass (Table 3 3). Zo ysiagrass produced higher visual quality than St. Augustinegrass (5.6 and 5.2, respectively). Throughout the year treated plots had higher visual quality than control plots. There were no differences between the soluble sources compared with sulfur coated sources (6 and 5.7, respectively). So luble sources were higher than PCUMIX and BS alone and combined with SCUMIX (5.2, 5.2 and 5.4, respectively). Turf quality

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42 values were lower than the acceptable level of 5.5 from PCU1, PCU2 (PCUMIX), and BS. Sulfur coated sources were higher than PCUMIX, suggesting a faster release of N. In 2009, in FC1 2, 3 and 4 zoysiagrass had higher quality than St. Augustinegrass (Tab le 3 4 ). The highly differences between zoysiagrass and St. Augustinegrass occurred in FC2 (5.7 and 5.2, respectively) during the hottest months of June and August. During this time, maximum soil and air temperature was 37.0 and 26.6 C, respectively (Fig ure 3 2 and 3 4). Scores from the PCUMIX and SCUMIX did not reach acceptable quality in FC 1 and 2. Biosolid (BS) treatment did not reach acceptable quality at any time during this yea r. The PCUMIX were lower in FC2 and 4 than SCUMIX. The rate and timing ( 120 days) of this treatment is likely the cause of this response and may indicate that this treatment is not suitable for maintaining turf quality when applied once every 120 days at the rates tested in this research. In 2010, responses were due to an inte raction of N sources and grass and (Table 3 2). As seen in other years, higher quality occurred in zoysiagrass. St. Augustinegrass had acceptable ratings from all treatments except for control and BS plots. In St. Augustinegras s, there were highly differen ces in turf quality between the untreated and treated plots when quality was averaged over the growing season. In 2010, no differences were observed between soluble and SCUMIX, SCUMIX and PCUMIX, and SCUMIX and PCUMIX mixed compared with BS, suggesting a s imilar N release from those sources in 2010. Soluble N sources both produced quality scores of 6.2, which were significantly higher than scores produced from PCUMIX or BS (5.5 and 5.1) and BS, SCUMIX and PCUMIX combined, which obtained a score of 5.5. Thes e results indicated a faster response from soluble sources and SCUMIX compared to PCUMIX

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43 and BS. Polymer coated sources had a slow response, which is reflected by the minimum acceptable score attained. Biosolid had the lowest visual quality scores. Mineral ization of the BS may reduce the release of N, resulting in reduced visual quality as reported by Castillo et al. (2011). Carrow (1997) demonstrated that natural organic fertilizers have an initial and long term N release in warm season grasses. Zoysiagras s produced acceptable ratings in all N sources except for control plots in 2010 which had lower visual quality than the treated plots (Table 3 2). Trenholm and Unruh (2007) have reported that Empire zoysiagrass produced higher visual quality than St. Augu stinegrass with less N, indicating that zoysiagrass is more responsive to N than St. Augustinegrass. In FC1, there were also differences between soluble vs. PCUMIX, soluble vs. MIX and SCUMIX vs. PCUMIX. All scores except for AN were below an acceptable ra ting in FC1. Faster responses from soluble sources were again seen in FC1. During FC1 only AN obtained acceptable visual quality, with a score of 5.6. In FC1, soil temperature was low and that could affect the nitrification process from Urea as compared wi th AN. No differences were observed between soluble and SCUMIX, SCUMIX and PCUMIX, and SCUMIX and PCUMIX mixed compared with BS, suggesting a similar N release from those sources in 2010. Trenholm and Unruh (2007) have reported that Empire zoysiagrass prod uced higher visual quality than St. Augustinegrass with less N, indicating that zoysiagrass is more responsive to N than St. Augustinegrass. In all FCs in St. Augustinegrass in 2010, there were differences due to N source (Table 3 5). Contrast analysis sho wed that the untreated plots had lower quality than the treated plots for each FC, with levels below acceptable quality in the untreated plots

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44 throughout the year. In FC1, there were significant differences between soluble sources vs. PCUMIX, BS, and MIX. Sulfur coated sources were significantly higher than PCUMIX in FC1. There were differences between SCUMIX and PCUMIX in FC1. In FC2, there were differences in visual quality between soluble sources and SCUMIX, with scores of 6.5 and 5.8, respectively. So lu ble sources were higher than PCUMIX and BS, and MIX during FC, 2. In FC3, no differences occurred between soluble sources and SCUMIX. Significant differences were found between soluble vs. PCUMIX, BS, and MIX. The polymer coate d sources increased in qualit y over time, related to the mechanism of N release over time, which resulted in no differences vs. SCUMIX. In FC4, the combination of SCU MIX and PCUMIX was higher than the BS (6.1 and 5.3, respectively). The BS in 2010 did not achieve acceptable visual qua lity score during any FC. Carrow (1997) found similar results with milorganite, which had lower visual quality than urea treated plots in Tifway bermudagrass. Carrow (1997) also compared polymer coated sulfur coated urea with soluble urea and reported simi lar average annual visual quality scores, which was similar to results in FC4 with soluble sources and PCUMIX, and SCUMIX and PCUMIX. Some climatological facts might have affected responses during 2010. Starting in FC3, extended periods of high temperatur es were recorded (Figure 3 3), causing multiple environmental stresses on the turf plots. Lack of differences may be related to continuous N release influenced by temperature in FC3. Similar results were noticed by Sartain (2008), who observed that one app lication of controlled release N source was sufficient to maintain turfgrass quality in St. Augustinegrass in an extended period. After FC2, all N sources except for control and BS showed acceptable ratings of 5.5,

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45 suggesting a sustained release of N by th e PCUMIX. There were no differences between SCUMIX and PCUMIX and BS during 2010, with the exception of FC2 and 4. The response of SCUMIX and PCUMIX was similar to the soluble sources, which might be attributed to the increased N release over time. In zoys iagrass in 2010 (Table 3 6), differences occurred in FC1, were s oluble sources was higher than PCUMIX and MIX. Sulfur c oated sources were higher than PCUMIX. No differences were observed between soluble sources and BS. Duri ng FC2, 3, and 4, no differences occurred between N sources, which agrees in the higher response to N reported by Trenholm and Unruh (2007). Color Color was af fected by the interaction of N source grass and year (Table 3 7). In 2008 and 2009, color differed due to both grass and N (Tab le 3 8) In 2010, color differed due to the inter action of N source and grass (Table 3 9 ). In 2008, St. Augustinegrass averaged an acceptable score of 5.8. Zoysiagrass scores were also above acceptable (6.8), and was significantly higher than St. Augustin egrass (Table 3 8). There were differences in 2008 between soluble sources and SCUMIX compared with PCUMIX. No differences were observed when those sources were compared with BS. Analysis by FC shows a response to main effects of grass and N source in each FC in 2008 (Table 3 10). In FC1 of 2008, soluble sources had higher scores than PCUMIX, BS and MIX. Sulfur coated sources also were higher than PCUMIX, with scores of 6.0 and 5 .4, respectively. No differences were obtained in FC2 due to the increase in co lor from the polymer coated sources and the BS.

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46 In 2009, average quality in St. Augustinegrass was 5.3, which is below acceptable (Table 3 8). This is similar to results for visual quality and may be due to the slower N release of Biosolid and PCUMIX. Zoys iagrass obtained a score of 5.9 whic h was higher than St. Augustinegrass. Treated plots had higher color scores than the untreated plots in both grasses. There were no differences in color between N sources with similar release characteristics. There were also no differences between soluble sources vs. SCUMIX. In contrast, differences were observed from soluble sources compared with PCUMIX, BS, and MIX. The combination of SCUM IX and PCUMIX were higher than BS. Soluble sources, SCUMIX were higher than other N sources in both years. In FC1 and 2 of 2009 (Table 3 10), all contrasts differed except for soluble vs. SCUMIX. In FC3, the BS scores were lower than other treatments, and in FC4 soluble sources had higher color scores than PCUMIX, BS and MIX. Biosolid was inconsistent in response, with increases in color scores in some FCs and not in others. The majority of differences occurred in FC1 and 2, where the soluble sources were significantly higher with each contrast with PCUMIX, BS and the combination of SCU MIX, PCUMIX and BS. No significant differences were observed in comparison between soluble sources and SCUMIX. Increases in scores were observed from the polymer coated sources from 5.2 to 6.1 and 5.4 to 6.0 from FC 2 to 3. Those increases resulted in no s ignificant differences when were compared with soluble sources and SCUMIX in FC3. Only differences were observed from the comparisons between soluble sources vs. BS and the combination of SCUMIX and PCUMIX vs. BS. The highest score from PCUMIX reaffirm the long term response from those sources compared to the rest of N sources. The FC3 corresponds to the months of August through October. The highest

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47 temperature on average observed during those months in 2009 was 36.4 C. It was possible that the temperature combined with rainfall affected the release of the material, increasing the scores at that FC. In FC4, PCUMIX had reduced scores, resulting in differences when the soluble materials were compared with the PCUMIX and also the SCUMIX compared with the PCUMI X. Climatological factors that might have affected 2009 color scores include total rainfall (1096.8 mm), which was higher than 2008 (904.7 mm). Higher temperatures in 2009 might have likewise influenced turf color. This combination of climatological facto rs may increase soil moisture, solubilizing the sulfur coat and increasing the diffusion rate from the granule of the fertilizers, increasing N release from the SCUMIX and PCUMIX, which resulted in greater color. In 2010, differences in color were affected by the interaction of turfgrass and N source (Table 3 9). In St. Augustinegrass there were differences between the untreated and the treated plots. There were no differences in color from soluble sources compared with SCUMIX. Similar responses were found by Hummel et al. (1981), who reported a good color response and slow release characteristics from SCU in Kentucky bluegrass compared with solu ble N sources. Other differences were observed with soluble sources compared with PCUMIX and the soluble sources c ompared with the combination of SCUMIX, PCUMIX and BS. Sulfur coated sources did not differ from PCUMIX, although both sources combined differed from BS. All N sources produced an acceptable rating except for control and Biosolid. Results observed in color by BS were similar to turf quality. The lower responses from BS in quality and color in St. Augustinegrass may attribute to the mineralization of the material, which has been

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48 previously reported. Castillo et al. (2011) reported that N organic mineralizati on fro m municipal BS was higher by incorporation into the first 15 to 20 cm of soil than when surface applied. According to Castillo at al., the N mineralization of BS i s in majority organic N, w hich that the plant can not take up r apidly N because it has t o be mineralized to NO 3 and NH 4 This process of convert ing natural N to available forms for the plants may take longer than in other N sources such soluble sources. Surface application used in this research may have influenced the mineralization rate to r elease constant N to the plant, which resulted in a lower color response from the BS. In zoy siagrass in 2010, no differences were seen between N sources. Untreated plots had lower color scores than treated plots. All N sources obtained an acceptable turf c olor rating >5.5, except the control. This is similar to the q uality results for zoysiagrass. Analysis by FC shows a response to main effects of grass and N source in each FC in 2008 and 2009, and in FC1 in 2010. The remaining FCs in 2010 were affected by the interaction of N source and grass (Table 3 10). In FC1 of 2010, scores were very low due to delayed spring green up .Only soluble sources produced acceptable co lor scores at this time, with a score <5.5 from the other N sources. The results are consist ent with Carrow (1997), who obtained higher color ratings in hybrid bermudagrass from soluble sources. The author noted poor initial and intermediate responses, but good long term color response from polymer coated urea. Hummel et al. (1984) des cribed that one application of SCU provided acceptable color through the summer, fall and spring in Kentuck y bluegrass. In this research, SCU provided a color similar to soluble sources. Biosolid did not maintain color comparable to the other N

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49 sources, other than in FC3. Temperatures averaged 36.5 C in FC3 may have increased mineralization of N, making more available for grass uptake. There was an interaction effect between N source and grass in FC2, 3 and 4 in 2010 (Table 3 11, 3 12). Nitrog en source effect was in St Augustinegrass in FC2, 3 and 4 (Table 3 11). Scores were higher in the treated plots than in the untreated plots. In FC 2, soluble sources were significantly higher than SCUMIX, PCUMIX, and BS and also against the combination of PCUMIX, SCUMIX, and BS. No significant differences were found from the contrast between SCUMIX and PCUMIX, suggesting similar N release from those materials. The BS did not produce acceptable color during any of these FCs, similar to what was observed with the visual quality. In contrast, zoysiagrass responded more uniformly to the N sources (Table 3 12). The only difference was non treated vs. treated plots, with no other color difference due to N source. A similar response were reported by Carrow (1997), who found no differences from 1 to 30 days in bermudagrass in response to different N sources against urea. According to our results, St. Augustinegrass requires specific N sources to obtain desirable color ratings. Faster results will occur from soluble N sources and sulfur coat ed sources. Polymer coated sources and BS will not produce acceptable color initially in St. Augustinegrass. Carrow (1997 ) reported a response of between 30 to 60 days for turf quality and color from a small granular size polymer coated urea Carrow also r eported that polymer coated urea with regular granule performed with highest long term N release for 61 to 95 days after application with 71 to 86% of turf quality and color greater than urea treated plots

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50 Shoot Growth Rate Shoot growth rate was affected by the interaction of grass and year and N source and year (Table 3 13). Shoot growth differed due to grass in 2008, with greater shoot growth in zoysiagrass (Table 3 14). In 2008, growth of zoysiagrass compared to St. Augustinegrass was 8.61and 5.89 kg D M ha 1 d 1 respectively, an increase of 59% more growth in zoysiagrass. In 2008, soluble sources (10.41 kg DM ha 1 d 1 ) produced higher shoot growth rate than PCUMIX and BS (4.89 and 7.03 kg DM ha 1 d 1 respective ly) (Table 3 15). No differences occurred between soluble and SCUMIX, SCUMIX and PCUMIX, and the combination of SCUMIX and PCUMIX vs. BS. There were differences in FC1 in 2008 due to N source and grass (Table3 16). Zoysiagrass produced 9.47 kg DM ha 1 d 1 which was higher than St. Augustinegrass which produced 5.34 kg DM ha 1 d 1 In FC1 maximum growth was produced by AN, Urea, SCU1, and SCU2 with lowest growth rate from PCU1 and PCU2. No differences occurred in FC2 for N source In 2009, no differences occurred between St Augustinegrass and z oysiagrass (Table 3 14). Also in 2009, solubl e sources produced higher shoot growth rate than PCUMIX, BS, and MIX. Sulfur coated sourc es produced higher shoot growth rate than PCUMIX (8.55 and 5.50 kg DM ha 1 d 1 respectively). No significant differences occurred between soluble sources and SCUMIX. In 200 9, zoysiagrass had greater shoot growth in FC1 and 2, while growth was greater in St. Augustinegrass for FC3 and 4. The growth rate produced in FC 3 was 15.37 and 7.88 kg DM ha 1 d 1 for St. Augustinegrass and Zoysiagrass respectively. In

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51 the FC3, according to the data register in soil temperature and air temperature (Figure 3 2, 3 4 ) were 36.4 and 25.3 C which could affect in the higher growth rate obtained from St. Augustinegrass. However, some of the zo ysiagrass was affected by take all root rot ( Gaeumannomyces graminis var. graminis ), which reduced shoot growth rate. There were differences in growth due to N in FC2 and 3. T he soluble sources and the SCUMIX sources produced higher growth rates in both cy cles. In FC 2 higher growth rates were produced by AN, Urea, and SCU1 ( 12.77, 9.97, and 12.63 kg DM ha 1 d 1 respectively ) Lowest shoot growth rate was produced by PCU2 and B S ( 1.82 and 2.38 kg DM ha 1 d 1 respectively). As seen previousl y, zoysiagrass had greater growth than St. Augustinegrass in 2010 (5.25 and 1.94 kg DM ha 1 d 1 respectively) (Table 3 14). Similar results were observed by Bowman et al. (2002), who reported that Emerald zo ysiagrass produced higher shoot growth than St. Augustinegrass in a greenhouse study. Agronomically, zoysiagrass produced greater biomass with the same fertilizer compared with St. Augustinegrass, which is favorable in terms of yield production. In contrast, from the stand point of a homeowner, that could mean an incr ease in mowing practices to maintain a desirable turf. However, the mowing frequency applied during this research was the recommended interval of 7 days, with no scalping problems observed. There were also differences due to N source variable in 2010 (Tab le 3 15). Average values showed that AN, Urea and SCU1 produced a higher growth rate than other treatments in 2009. There was greater growth from SCUMIX than from PCUMIX ( 8.55 and 5.5 kg DM ha 1 d 1 respectively) All treated plots produced more shoot gro wth than control plots. In 2010, treated plots had greater growth than control plots

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52 and soluble sources produced more than the biosolid treatment ( 4.48 and 2.93 kg DM ha 1 d 1 respectively ). Carrow (1997) reported a similar decline in growth from Milorgani te compared to p olymer coated urea and Urea He attributed this to a longer term response to polymer coated sources increasing their release over time. No significant differences were obtained from the contrast between soluble sources and SCUMIX, which was similar to results obtained for visual quality and color. Results obtained from SCU1 treatments showed yield equal to that produced by soluble sources. Similar results were reported by Sartain (2008), who found no differences in dry matter between soluble Urea compared with s ulfur coated urea There was an interaction of N sources by grass for shoot growth in FC1, 3 and 4 in 2010. In St. Augustinegrass, each of these FCs had a response to N source (Table 3 17). Significantly higher growth was obtained from the treated plots vs. the untreated plots in these FCs. In FC1, higher growth was obtained from soluble sources vs. SCUMIX, PCUMIX, BS, and MIX. Maximum growth rate was obtained from AN and Urea, which produced 1.50 and 1.77 kg DM ha 1 d 1 In contrast, l owest growth rates were obtained from PCU1, PCU2, and BS with 0.68, 0.43, and 0.22 kg DM ha 1 d 1 In FC3, there were differences between soluble sources vs. BS and MIX. Lowest growth occurred with BS, which produced 1.63 kg DM ha 1 d 1 vs. 3.8 kg DM ha 1 d 1 from the controlled release sources. In FC4, there were again differences in growth between In zoysiagrass, in FC1, differences were observed from PCU1 and PCU2, which produced 2.78 and 1.20 kg DM ha 1 d 1 respectively. Ammonium nitrate, which produc ed 2.6 kg DM ha 1 d 1, differed from BS, which produced 1.5 kg DM ha 1 d 1 Sulfur coate d sources produced higher dry matter than PCUMIX and BS with 3.0, 1.9,

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53 and 1.5 kg DM ha 1 d 1 In FC3 and 4, the only differences were between the untreated plots vs. t he treated plots. These results are similar to those obtained for, turf quality and color. Nitrogen sources respond as expected in St Augustinegrass, with soluble sources and SCUMIX providing very similar responses and the PCUMIX with initial slow response s and better response over time. Biosolid tended to not provide adequate response in St Augustinegrass compared with other N sources. In zoysiagrass, as in turf quality and color, any N source tended to produce similar growth. Nitrogen Content Shoot growth was analyzed for total N content. Total Nitrogen Kjeldahl concentration in the clippings was multiplied by the dry matter to calculate an estimate of N content in a specific date for each fertilizer cycle. Nitrogen content was affe cted by the interactions of grass and year and N source and year (Table 3 19). Control plots had significantly lower N concentration than the treated plots fo r the three years of evaluation In 2008, levels were 1.30 vs. 0.73 kg N ha 1 for zoysiagrass and St. Augustinegrass, resp ectively (Table 3 20). In 2008, higher N levels were found in soluble sources and SCU1. In 2008, s oluble sources had higher N than PCUMIX, with levels of 1.54 and 0.62 kg N ha 1 respectively (Table 3 21). The s oluble sources had higher N content than the combination of SCUMIX, PCUMIX, and BS with 1.54 and 0.93 kg N ha 1 respecti vely. Sulfur coated sources, were higher than PCUMIX Biosolid levels did not differ from the soluble sources. In 2008, differences were due to N source and grass in FC1 and due to g rass only in FC2 (Table 3 22). In both FC s, zoysiagrass had higher N content than St. Augustinegrass. Zoysiagrass levels for FC1 and 2 were 1.43 and 1.16 kg N ha 1 compared to 0.66 and 0.79 kg N ha 1 for St. Augustinegrass. In FC1, higher N was

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54 obtained fr om soluble sources and SCUMIX sources and lowest from PCUMIX sources. Cont rast analysis showed differences between soluble sources vs. PCUMIX, soluble sources vs. MIX, and SCUMIX vs. PCUMIX. The results showed a lower N concentration from PCUMIX sources, w hich would be due to the slower N release of this product. In 2009, No differences occurred between St. Augustine and zoysiagrass shoot growth rate (1.21 and 1.06 kg N ha 1 respectively) (Table 3 20). In 2009, soluble sources and the SCUMIX obtained highe r N content values than the rest of N sources on average (Tab le 3 21). There were differences between soluble sources vs. all the contrast such as PCUMIX, BS, and the MIX. Lower N uptake was obtained from PCUMIX and BS, which obtained levels of 0.87 and 0. 71 kg N ha 1 Sulfur coated urea sources were higher than PCUMIX with 1.54 and 0.87 kg N ha 1 Sulfur coated urea sources had a similar N response than soluble sources, which was faster than the PCUMIX. In 2009, results of the analysis of variance showed a n effect due to grass in FC1, 3 and 4 (Table 3 22). Nitrogen source responses were observed in FC2, 3 and 4. Zoysiagrass obtained higher N content than St. Augustinegrass in FC1 with 1.02 and 0.33 kg N ha 1 respectively. No differences were observed in FC 2. In contrast, St. Augustinegrass had higher N content than zoysiagrass in FC3 (2.47, 1.59 kg N ha 1 respectively). In FC4 St. Augustinegrass was also higher than zoysiagrass (1.28, 0.56 kg N ha 1 ). Differences due to N source were found in FC2 and 3, whi ch correspond to the growing season. Higher N content in FC2 was obtained from soluble sources, which on average resulted in levels of 2.74 kg N ha 1 and SCUMIX, at a content of 2.47 kg N

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55 ha 1 Lowest levels were obtained from PCUMIX sources and BS with 0. 26 and 0.26 kg N ha 1 respectively. In addition, in FC3 higher N content was obtained from soluble sources and SCUMIX sources (3.08 and 2.78 kg N ha 1 respectively). Contrast analysis showed that in FC2 and 3 the soluble sources were significantly higher than PCUMIX, BS and MIX in each of the contrasts. In contrast, SCUMIX obtained simil ar N resulting in no differences between soluble sources and SCUMIX. In addition, SCUMIX N content was significant higher than PCUMIX. The combination of SUCMIX and PCUMIX compared with BS did not differ. In 2010, zoysiagrass had 1.18 vs. 0.41 kg N ha 1 for St. Augustinegrass (Table 3 20). Higher N content produced by zoysiagrass might have been due to greater root length density from 0 to 15 cm, and an accumulation effect o f N produced by this variety. In 2010, all N sources resulted in similar N content and all were higher than the control plots (Table 3 21). Results were analyzed by FC to evaluate the N content over time. In 2010, there was an interaction in FC1, 3 and 4 due to N source and grass (Table 3 22). In St. Augustinegrass, N concentration was affected by N source in all 3 FCs (Table 3 23). Higher N was obtained from the soluble sources and the SCUMIX sources which obtained on average 0.45, and 0.25 kg N ha 1 Lowe st N was from the PCUMIX sources and the BS in FC1 (0.12 and 0.04 kg N ha 1 respectively). The contrast analysis showed that significantly higher differences were found from the treated plots than from control plots. Soluble sources obtained significantly higher N than SUCMIX, PCUMIX, BS and MIX. No significant differences occurred between the contrasts that involved SCUMIX vs. PCUMIX, SCUMIX and PCUMIX vs. BS.

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56 In zoysiagrass, there were differences due to N source in all FCs which was similar to growth ra te which was resulted in higher N from zoysiagrass than from St. Augustinegrass (Table 3 24). The contrast analysis showed differences between treated vs. non treated plots, with no differences due to N source. Total Kjeldahl Tissue Nitrogen Concentration in Tissue Leaf tissue N concentration was obtained by the determination of total N in the tissue of each harvest to evaluate the N concentration. Leaf tissue N concentration was aff ected by the interaction of N source and year (Table 3 16). Analyzing resu lts by year, the N source variable was highly significant for each year. The results showed an increase in concentration over time in all N sources except for the control. According to contrast analysis, higher differences occurred each year between the tr eated plots vs. the untreated plots, which obtained very low N concentrations. In 2008, the soluble sources obtained N concentrations of 21.66 (AN), 21.35 (Urea) and 20.61 (SCU1) g N Kg 1 DM (Table 3 26). The rest of the sources obtained values less than 2 0 g N kg 1 DM which is the acceptable range for St. Augustinegrass and zoysiagrass according to previous research. Sartain (2001) and Hochmuth et al. (2009) considered this rate as a good to very good quality turfgrass. The contrast analysis showed that th e soluble sources on average were significantly higher than PCUMIX, BS, and MIX from each of the contrasts. The contrast between soluble sources vs. SCUMIX did not show differences due to responses from SCU1, which was equal to the soluble level of 20.61 g N kg 1 DM. SCU2, PCU1, PCU2 and, BS did not obtain sufficient N concentration in the tissue. Other differences obtained were from the contrast of the combination of SCUMIX and PCUMIX vs. BS, which obtained 19.16 and

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57 17.26 g N kg 1 DM, respectively. Biosol id had the lowest N concentration in 2008. Analyzed by FC (Table 3 27), there were differences between grasses, with higher values in zoysiagrass for FC1 and 2 (19.86 and 21.51 g N kg 1 DM) in comparison with St. Augustinegrass (16.12 and 18.20 g N kg 1 DM ). In 2009, results showed a similar response, with highest N concentration from AN, Urea and, SCU1 (25.74, 25.18, and 26.82 g N kg 1 DM, respectively) (Table 3 26). In contrast to 2008, the rest of the N sources obtained adequate N. Th e contrasts showed h igher differences from soluble sources compared with PCUMIX, BS, and the combination of them, including SCUMIX. No differences were obtained from the contrast of the combination of SCUMIX and PCUMIX vs. BS because those sources obtained similar N concentra tion ranges. Analyzed by FC, effects were due to N source and grass in FC1, 2 and 3 (Table 3 27). In FC 4, significant effects were due to N source only. Zoysiagrass had higher N concentratio n than St. Augustinegrass in FC 1 and 3, but not in FC2. Contrast analysis showed th at Zoysiagrass was higher than St. Augustinegrass in FC2 with 21.51 compared to17.65 g N kg 1 DM. The St. Augustinegrass concentration was lower than what would provide acceptable grass. In FC 3, zoysiagrass was again higher than St. Augu stinegrass with 24.24 compared to 20.24 g N kg 1 DM. N o differences occurred in FC 4. The N content data before showed that increased in N uptake from zoysiagrass form those cycles were only 0.05 kg N ha 1 In contrast, zoysiagrass increased 0.70 kg N ha 1 in the same period, 93.3% increase from St. Augustinegrass compared with only 6.7% from zoysiagrass. Soluble sources and SCUMIX had the highest N concentration values in FC1 and 2. Contrast analysis showed higher levels in treated plots vs. control

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58 plots. In FC1, there were differences between soluble sources and PCUMIX. Polymer coated urea 1 and BS produced the lower N concentrations with 16.82 and 17.95 g N kg 1 DM, respectively. Quiroga (2001) found that hybrid bermudagrass obtained higher N concentratio ns from Urea and SCU vs. Ureaform. Graham et al. (2002), reported less N tissue concentration from milorganite compared with Urea and sulfur coated urea in bentgrass ( Agrostis stolonifera L.). Polymer coated urea 1 and Biosolid did not reach the sufficient 1 DM). In FC2 a slightly increase occurred in all N sources, such SCU1, SCU2, PCU1 and, Biosolid. However two N sources did not produced sufficient N concentrations ranges such PCU2 and Bio solid. In FC3, all N sources had N concentrations above the sufficient range. Higher N concentrations were obtained from AN, Urea and SCU1. Contrast analysis showed that the so luble sources were higher in comparisons with PCUMIX, BS, and MIX. Sulfur c oated sources were higher than PCUMIX. Sulfur coated sources had a response similar to the soluble sources. In FC4, the N concentrations for all N sources were above than the sufficient range. The mean for the N sources excluding the control for that FC were be tween 29.82 and 32.82 g N kg 1 DM with a 95% of confidence. The contrast analysis showed no significant differences between all contrasts that include the N sources. In 2010, no diffe rences were found (Table 3 26). Analyzed by FC, interactions occurred in FC1, 2 and 3, due to N source and grass (Table 3 27). In FC 4 effects occurred only due to N source. In FC1, contrast analysis did not reveal differences between grasses; however, there were differences due to N

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59 source. The soluble sources had higher TKN t han the BS with 34.45 and 29.17 g N kg 1 DM, respectively. In FC2, there was an interaction of N source by grass. Nitrogen sources differed in both turfgrasses (Table 3 28). In St. Augustinegrass, higher N concentrations were produced by AN, Urea, and SCU1 and lower N tissue concentrations were produced by PCU2 and BS in FC 1 and 2. Soluble sources and PCUMIX did not statistically differ from all the FCs mentioned, suggesting a similar N release. The contrast analysis showed that in FC1 higher N concentrati ons were obtained from soluble sources vs. BS and PCUMIX and the combination of them and SCUMIX. The combination of SCUMIX an d PCUMIX were also higher than BS. The soluble sources were greater than PCUMIX and BS in FC1 but in the rest of FCs Urea did not d iffer from PCUMIX, which might be attributed to the longer and slower response form PCUMIX vs. BS. In FC2, no differences were obtained from soluble sources vs. PCUMIX, BS and the combination of them and SCUMIX. Sulfur coated urea s ources were higher than PCUMIX, which is predictable due to the similar response from between SCUMIX and the soluble sources. No differences occurred between the combination of SCUMIX, PCUM IX and BS. In FC3, higher differences were obtained from soluble sources compared to BS and the combination of SCUMIX, PCUMIX and BS. Biosolid was significantly lower than the combination of SCUMIX and PCUMIX. No significant differences were obtained from the contrast between SCUMIX and PCUMIX. In zoysiagrass there were no differences in any FC, other than treated vs. un treated plo ts (Table 3 29). McCrimmon (2000 ) reported that zoysiagrass cultivars under high N treatments did not differ from each other for TKN and that cultivars under low N

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60 treatments had similar concentrations than higher tre atments. These responses indicate that high N rates are not needed for zoysiagrass to maintain adequate N concentration. Root Growth The analysi s of variance showed differences due to grass and sampling date (Table 3 30). St. Augustinegrass produced higher root weight (4.31 vs. 2.76 kg DM m 3 ) surface area (1.01 vs. 0.85 cm 2 cm 3 ) and volume (0.23 vs. 0.14 cm 3 cm 3 ) than zoysiagrass (Table 3 31). Contrast analysis showed that there were no significant differences in RW on May 12 as compared to July 12, ho wever, greater RW was produced on May 12 compared to Oct 12 and July 12 compared to Oct 12. This is not surprising, as root growth of warm season grasses slows considerably in the fall months. Root surface area and RV were greatest in July, followed by May and lowest in Oct (Table 3 31), again standard for warm season grass growth. Similar results were reported by Gonzalez (2010), who observed similar seasonal patterns for r oot growth. Root biomass, RLD, RSA and RV in the top 15 cm of the soil profile were less at the beginning and at the end of the growing season and greatest in mid summer. Root length density (RLD) showed a significant interaction for sampling date and grass (table 3 32). Both grasses had higher RLD during July 12 (9.69 and 7.14 cm 3 cm 3 following by May 12 (4.93 and 4.53 cm 3 cm 3 ) and least RLD in October 12 (3.49 and 3.13 cm 3 cm 3 ). Contrast analysis showed greater RLD in zoysiagrass on July 12 (9.69 and 7.14 cm 1 cm 3 respectively), with no differences between grass on the other sam pling dates The results disagree with Bowman et al. (2002), who reported that St. Augustinegrass had higher total root biomass compared with zoysiagrass. St.

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61 Augustinegrass produced more roots at deeper depths, which could increase its ability to absorb n utrients and reduce N losses. Root variables (RW, RSA, RV, and RLD) were analyzed by depth (0 15 cm and 15 30 cm). At 0 15 cm, there were no differences due to N sources on any date. (Table 3 34). There were differences between grasses on May 12 and July 1 2 for RV and RLD. On both dates, St. Augustinegrass had greater RV while zoysiagrass had greater RLD. At 15 30 cm, there were differences due to grass for all variables on all dates, except for RSA on 12 July. Greater root measurements were found for St. A ugustinegrass for all variables on all dates, with the exception of RLD on 12 July. These data indicate that RLD is greater in zoysiagrass in the top 15 cm, but all rooting measurements are greater in St. Augustinegrass at the deeper levels. Fuentealba (20 10) reported higher volume, RLD and root dry weight in St. Augustinegrass vs. Empire zoysiagrass at a depth of 30 cm. Similarly, Bowman, et al. (2002) documented greater RLD in St. Augustinegrass at 21 to 31 cm depth in a greenhouse study. In May12, St. Au gustinegrass obtained significant higher RW, RSA, RV and RLD than zoysiagrass. In July 12 again St. Augustinegrass was significant higher than zoysiagrass in RW and RV. No significant differences were produced in RSA and RLD. In October 12, St. Augu stinegr ass again was higher in RW, RSA RV, and RLD than zoysiagrass.

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62 Table 3 1. ANOVA table for visual quality. ANOVA DF Visual Quality (1 9) p value Year (Y ) 2 <.0001 Grass (G) 1 <.0001 G*Y 2 0.0039 N source (N) 7 <.0001 N*Y 14 <.0001 N *G 7 <.0001 N Y *G 14 <.0001

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63 Table 3 2. Effect of N sources on visual qua lity on St. Augustinegrass and z oysiagrass in 2008 and 2010. Turfgrass N Source Visual Quality 2008 2010 St. Augustinegrass Control 5.6 2.6 AN 5.8 6.2 Urea 5.9 6.2 SCU1 6.0 5.9 SCU2 5.3 5.8 PCU1 5.6 5.5 PCU2 5.8 5.5 Biosolid 5.9 5.1 Contrasts Control vs. Others NS *** Soluble vs. SCUMIX NS NS Soluble vs. PCUMIX NS Soluble vs. BS NS Soluble vs. MIX NS SCUMIX vs. PCUMIX NS NS SCUMIX & PCUMIX vs. BS NS NS Zoysi agrass Control 5.6 4.1 AN 6.1 6.2 Urea 5.9 5.8 SCU1 6.0 5.7 SCU2 5.9 5.9 PCU1 6.0 5.9 PCU2 5.8 5.7 Biosolid 5.9 5.9 Contrasts Control vs. Others NS *** Soluble vs. SCUMIX NS NS Soluble vs. PCUMIX NS NS Soluble vs. BS NS NS Soluble v s. BS & SCUMIX & PCUMIX NS NS SCUMIX vs. PCUMIX NS NS SCUMIX & PCUMIX vs. BS NS NS ANOVA DF p value N source (N) 7 0.7427 <.0001 Grass (G) 1 <.0001 <.0001 N*G 7 0.0003 <.0001 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SCU1= s ulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. =Single degree contrasts performed at the alpha level 0.05.

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64 Table 3 3. Effect of turfgrasses and N sources in visual quality in 2009. Vi sual Quality 2009 (1 9) Turfgrasses St. Augustinegrass 5.2 Zoysiagrass 5.6 Contrast SA vs. ZO *** N sources Control 4.3 AN 6.1 Urea 5.9 SCU1 5.8 SCU2 5.6 PCU1 5.3 PCU2 5.2 Biosolid 5.2 Contrasts Control vs. Others *** Soluble vs. SC UMIX NS Soluble vs. PCUMIX *** Soluble vs. BS *** Soluble vs. MIX *** SCUMIX vs. PCUMIX SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N source (N) 7 <.0001 Grass (G) 1 <.0001 N*G 7 0.4305 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treat ment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 a nd polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped ; MIX= SCUMIX, PCUMIX, and Biosolid grouped =Single degree contrasts per formed at the alpha level 0.05. SA= St. Augustinegrass, ZO= Zoysiagrass. =Single degree con trasts performed at the alpha level 0.05.

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65 Table 3 4. The response of N sources during the fertilizer cycles in visual quality in in 2008, and 2009 Treatment Visual Quality 2008 2009 FC1 FC1 FC2 FC3 FC4 Ratings Scale (1 9) Control 5.5 4.3 4.3 4.3 4.0 AN 5.9 5.7 6.2 6.4 6.1 Urea 5.9 5.6 6.0 6.2 5.9 SCU1 5.9 5.4 6.0 6.2 5.9 SCU2 5.5 5.4 5.7 5.7 5.6 PCU1 5.8 5.2 5.2 5.8 5.2 PCU2 5.7 5.0 5.1 5.6 5.1 Biosolid 5.9 5.0 5.2 5.4 5.2 Contrasts Control vs. Others NS *** *** *** *** Soluble vs. SCU MIX NS NS NS NS NS Soluble vs. PCUMIX NS ** *** ** ** Soluble vs. BS NS ** *** ** Soluble vs. MIX NS ** *** ** SCUMIX vs. PCUMIX NS NS *** NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS Turfgrasses St. Augustinegrass 5.6 4.9 5.2 5.6 5.2 Zoysiagras s 5.9 5.5 5.7 5.8 5.5 Contrast SA vs. ZO *** ** *** ANOVA DF p value N source (N) 7 0.8415 <.0001 <.0001 <.0001 0.0006 Grass 1 <.0001 0.0022 <.0001 0.0237 0.0164 N*G 7 0.1214 0.9719 0.2244 0.6537 0.3123 NS, * **, = P>0.05, P<0.05, P<0.01 P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped; SA= St. Augustinegrass; ZO= Zoysiagrass. = Single degree contrasts performed at the alpha level 0.05. =M eans of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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66 Table 3 5. The response of N sour ces during the fertilizer cycle (FC) in St. Augustinegrass visual quality in FC2 in 2008 and in FC1, 2, 3, and 4 in 2010. Treatment St. Augustinegrass Visual Quality 2008 2010 FC2 FC1 FC2 FC3 FC4 Ratings Scale (1 9) Control 5.8 2.7 2.3 2.6 3.1 AN 5.8 5.4 6.5 6.7 6.6 Urea 6.0 5.4 6.5 6.6 6.5 SCU1 6.1 5.0 5.9 6.5 6.3 SCU2 5.4 5.3 5.8 6.2 6.1 PCU1 5.8 4.8 5.5 5.9 6.1 PCU2 5.9 4.7 5.5 6.1 6.1 Biosolid 6.0 4.8 5.0 5.4 5.3 Contrasts Control vs. Others NS *** *** *** *** Soluble vs. SCUMIX NS NS ** NS NS Soluble vs. PCUMIX NS *** *** NS Soluble vs. BS NS *** *** ** ** Soluble vs. MIX NS *** *** SCUMIX vs. PCUMIX NS ** NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source (N) 7 0.2949 <.0 001 <.0001 <.0001 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= su lfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to O ctober December.

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67 Table 3 6. The response of N sources d uring the fertilizer cycle (FC) in z oysiagrass visual quality in FC2 in 2008 and in FC1, 2, 3, and 4 in 2010. Treatment Zoysiagrass Visual Quality 2008 2010 FC2 FC1 FC2 FC3 FC4 Ratings Scale (1 9) Control 5.6 4.1 4.0 4.4 3.8 AN 6.1 5.6 6.2 6.5 6.5 Urea 5.8 5.3 5.9 6.4 5.8 SCU1 5.9 5.2 6.0 6.0 5.8 SCU2 5.9 5.3 6.0 6.2 6.0 PCU1 6.0 5.0 5.8 6.5 6.6 PCU2 5.9 4.7 5.4 6.7 6.3 Biosolid 5.9 5.1 5.8 6.5 6.5 Contrasts Control vs. Others NS *** *** *** *** Soluble vs. SCUMIX NS NS NS NS NS Soluble vs. PCUMIX NS ** NS NS NS Soluble vs. BS NS NS NS NS NS Soluble vs. MIX NS NS NS NS SCUMIX vs. PCUMIX NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS ANOVA DF p value N source (N) 7 0 .5610 0.0003 0.0359 0.0021 0.0004 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; S CUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts perf ormed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 corres pond to October December.

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68 Table 3 7. ANOVA table for color. ANOVA DF Color (1 9) p value Year (Y ) 2 <.0001 Grass (G) 1 <.0001 G*Y 2 0.0068 N source (N) 7 <.0001 N*Y 14 <.0001 N *G 7 <.0001 N *Y *G 14 <.0001 Table 3 8. Effect of turfgrasses and N sources on color in 2008 and 2009. Color 2008 and 2009 (1 9) 2008 2009 Turfgrasses St. Augustinegrass 5.8 5.3 Zoysiagrass 6.0 5.7 Contrast SA vs. ZO *** *** Control 5.4 4.1 AN 6.2 6.0 Urea 6.1 6.0 SCU1 6.2 5.9 SCU2 6.0 5.8 PCU1 5.7 5.6 PCU2 5.7 5.5 Biosolid 5.9 5.3 Contrasts Control vs. Others *** *** Soluble vs. SCUMIX NS NS Soluble vs. PCUMIX ** ** Soluble vs. BS NS *** Soluble vs. MIX ** SCUMIX vs. PCUMIX SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N so urce (N) 7 0.0007 <.0001 Grass (G) 1 <.0001 <.0001 N*G 7 0.7225 0.9333 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 appl ied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid gr ouped =Single degree contrasts per formed at the alpha level 0.05. SA= St. Augustinegrass, ZO= Zoysiagrass. =Single degree contrasts performed at the alpha level 0.05.

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69 Table 3 9. The effect of N sources on St. Augustinegrass and z oysiagrass color in 2010 Turfgrass N Source Color 2010 St. Augustinegrass Control 2.6 AN 6.1 Urea 6.0 SCU1 5.8 SCU2 5.8 PCU1 5.5 PCU2 5.6 Biosolid 5.0 Contrasts Control vs. Others *** Soluble vs. SCUMIX NS Soluble vs. PCUMIX ** Soluble vs. BS *** Solu ble vs. MIX *** SCUMIX vs. PCUMIX NS SCUMIX & PCUMIX vs. BS ** Zoysiagrass Control 4.1 AN 6.1 Urea 6.0 SCU1 6.0 SCU2 6.0 PCU1 6.0 PCU2 6.0 Biosolid 6.0 Contrasts Control vs. Others *** Soluble vs. SCUMIX NS Soluble vs. PCUMIX NS Soluble vs. BS NS Soluble vs. MIX NS SCUMIX vs. PCUMIX NS SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N source (N) 7 <.0001 Grass (G) 1 <.0001 N*G 7 <.0001 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: Others= urea, ammonium ni trate, sulfur coated urea 1, sulfur coated urea 2, polymer coated urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cy cle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. =Single degree contrasts performed at the alpha level 0.05.

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70 Table 3 10. The response of N sources during the fertilizer cycles in color in 2008, 2009, and 2010. Treatment Color 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 Ratings Scale (1 9) Control 5.3 5.5 4.2 4.1 4.0 4.0 3.2 AN 6.3 6 .1 5.7 6.1 6.1 6.1 5.5 Urea 6.1 6.1 5.8 6.2 6.0 6.0 5.5 SCU1 6.2 6.1 5.6 6.1 6.1 6.0 5.2 SCU2 5.9 6.1 5.6 6.1 5.8 5.6 5.5 PCU1 5.5 5.9 5.4 5.2 6.1 5.3 5.1 PCU2 5.4 6.1 5.3 5.4 6.0 5.1 5.0 Biosolid 5.8 5.9 5.1 5.3 5.4 5.3 5.1 Contrasts Contr ol vs. Others *** *** *** *** *** *** *** Soluble vs. SCUMIX NS NS NS NS NS NS NS Soluble vs. PCUMIX *** NS ** *** NS ** *** Soluble vs. BS NS *** *** *** Soluble vs. MIX ** NS ** *** NS *** SCUMIX vs. PCUMIX *** NS *** NS ** SCUMIX & PCU MIX vs. BS NS NS NS NS Turfgrasses St. Augustinegrass 5.7 5.9 5.1 5.4 5.5 5.3 4.9 Zoysiagrass 5.9 6.1 5.6 5.7 5.8 5.5 5.2 Contrast SA vs. ZO ** *** *** *** ** ANOVA DF p value N source (N) 7 <.0001 0.0025 <.0001 <.0001 <.0001 0.0002 <.0 001 Grass (G) 1 0.0029 <.0001 0.0130 <.0001 <.0001 0.0444 0.0014 N*G 7 0.9738 0.5175 0.9999 0.2523 0.3653 0.2463 0.1057 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polym er coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped; SA= St. Augustinegrass; ZO= Zoysiagrass. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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71 Table 3 11. The response of N sources by the fertilizer cycle (FC) in St. Augustinegrass color in FC 2, 3, and 4 in 2010. Treatment St. Augustinegrass Color 2010 FC2 FC3 FC4 Ratings Scale (1 9) Control 2.3 2.6 3.0 AN 6.2 6.6 6.5 Urea 6.3 6.3 6.2 SCU1 5.7 6.3 6.5 SCU2 5.8 6.1 5.6 PCU1 5.5 6.0 5.6 PCU2 5.7 6.1 5.6 Biosolid 5.1 5.2 4.8 Contras ts Control vs. Others *** *** *** Soluble vs. SCUMIX NS NS Soluble vs. PCUMIX ** NS Soluble vs. BS *** ** *** Soluble vs. MIX ** ** SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS NS ** ** ANOVA DF p value N source (N) 7 <.0001 <.0001 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.0 5. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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72 T able 3 12. The response of N sources by the fertilizer cycle (FC) in z oysiagrass color in FC2, 3 and 4 in 2010. Treatment Zoysiagrass Color 2010 FC2 FC3 FC4 Ratings Scale (1 9) Control 3.8 4.8 4.0 AN 6.1 6.5 6.5 Urea 5.8 6.4 6.0 SCU1 6.0 6.5 6.4 SCU2 6.1 6.4 6.3 PCU1 6.0 6.5 6.3 PCU2 6.0 6.6 6.3 Biosolid 6.0 6.6 6.3 Contrasts *** *** *** Control vs. Others NS NS NS Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX NS NS NS Soluble vs. BS NS NS NS S oluble vs. MIX NS NS NS SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source (N) 7 <.0001 0.0039 0.0010 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMI X, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October De cember, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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73 Table 3 13. ANOVA table for shoot growth rate. ANOVA DF Shoot Growth Rate (kg DM ha 1 d 1 ) p value Year (Y ) 2 <.0001 Grass (G) 1 <.0001 G*Y 2 <.0001 N source (N) 7 0.0011 N*Y 14 0.0002 N *G 7 0.3970 N *Y *G 14 0.7061 Table 3 14. The effect of turfgrasses on shoot growth rate in 2008, 2009, and 2010. Turfgrasses 2008 2009 2010 kg DM ha 1 d 1 St. Augustinegrass 5.89 7.05 1.94 Zoysiagrass 8.61 6.23 5.25 Con trast SA vs. ZO *** NS *** ANOVA DF p value Grass 1 0.0003 0.2830 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SA= St. Augustinegrass, ZO= Zoysiagrass. = Single degree contrasts per formed at the alpha level 0.05.

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74 Table 3 15 The effect of N sources on shoot growth rate in 2008, 2009, and 2010. Treatment 2008 2009 2010 kg DM ha 1 d 1 Control 3.17 1.49 0.48 AN 10.49 10.00 4.42 Urea 10.34 8.92 4.55 SCU1 10.62 10.11 3.89 SCU2 6.59 7.00 4.61 PCU1 4.67 5.60 4.33 PCU2 5.11 5.41 3.54 Biosolid 7.03 4.58 2.93 Contrasts Control vs. Others *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX ** NS Soluble vs. BS NS ** Soluble vs. MIX NS SCUMIX vs. PCUMIX NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source 7 0.0766 0.0017 0.0005 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: Others= urea, ammonium nitrate, sulfur coated urea 1, sulfur coated urea 2, polymer coated urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coat ed urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 an d polymer coated urea 2 gro uped; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts per formed at the alpha level 0.05.

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75 Table 3 16. The effect of turfgrasses and N sources on shoot growth rate by fertilizer cycle in 2008, 2009, and 2010. Treatment Shoot Growth Rate 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC2 kg DM ha 1 d 1 Control 2.86 3.48 2.93 0.29 1.73 1.02 1.19 AN 10.97 10.01 5.08 12.77 17.35 4.78 6.68 Urea 12.63 8.04 5.98 9.97 14.48 5.26 7.39 SCU1 12.28 8.96 5.06 12.63 17.41 5.34 6.33 SCU2 7.64 5.55 5.59 5.29 12.26 4.88 7.68 PCU1 2.96 6.38 3.79 2.02 11.78 4.82 7.92 PCU2 2.44 7.78 5.21 1.82 8.99 5.61 6.66 Biosolid 7.46 6.59 4.56 2.38 9.00 2.37 5.45 Contrasts Control vs. Others NS NS ** *** ** ** Soluble vs. SCUMIX NS NS NS NS NS NS NS Soluble vs. PCUMIX *** NS NS *** NS NS Soluble vs. BS NS NS NS *** NS NS Soluble vs. MIX NS NS *** NS NS NS SCUMIX vs. PCUMIX ** NS NS ** NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS Turfgrasse s St. Augustinegrass 5.34 6.44 2.65 4.30 15.37 5.89 4.42 Zoysiagrass 9.47 7.76 6.90 7.49 7.88 2.63 10.38 Contrast SA vs. ZO *** NS *** ** *** *** *** ANOVA DF p value N source (N) 7 0.0127 0.3551 0.7768 0.0001 0.0040 0.0829 0.0010 Grass (G) 1 0.0 007 0.1599 0.0007 0.0036 0.0001 <.0001 <.0001 N*G 7 0.1868 0.8990 0.9727 0.4549 0.5198 0.0912 0.1534 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PC U2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammon ium nitrate and Urea grouped; MIX= S CUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: Octobe r December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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76 Table 3 17. The response of N sourc es by the fertilizer cycle (FC) in St. Augustinegrass shoot growth rate in FC1, 3, and 4 in 2010. Treatment St. Augustinegrass Shoot Growth Rate 2010 FC1 FC3 FC4 kg DM ha 1 d 1 Control 0.21 0.85 0.04 AN 1.50 5.05 0.50 Urea 1.77 4.77 0.35 SCU1 0.89 3.62 0.31 SCU2 1.25 3.80 0.28 PCU1 0.68 4.10 0.37 PCU2 0.43 3.68 0.27 Biosolid 0.22 1.63 0.05 Contrasts Control v s. Others ** ** Soluble vs. SCUMIX NS NS Soluble vs. PCUMIX *** NS NS Soluble vs. BS *** ** ** Soluble vs. MIX *** SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS ANOVA DF p value N source (N) 7 0.0008 0.0144 0.0168 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evalua tions events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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77 Table 3 18. The respons e of N sources by the f ertilizer cycle (FC) in z oysiagrass shoot growth rate in FC1, 3, and 4 in 2010. Treatment Zoysiagrass Growth Rate 2010 FC1 FC3 FC4 kg DM ha 1 d 1 Control 0.18 1.53 0.15 AN 3.04 8.71 1.56 Urea 2.69 10.02 2.28 SCU1 2.69 9.04 1.52 SCU2 3.55 11.56 2.69 PCU1 2.78 11.75 3.21 PCU2 1.20 9.64 2.67 Biosolid 1.52 9.27 2.28 Contrasts Control vs. Others *** *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX NS NS NS Soluble vs. BS NS NS Soluble vs. MIX NS NS NS SCUM IX vs. PCUMIX NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source (N) 7 0.0004 0.0010 0.0094 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated ur ea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped ; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4 : October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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78 Table 3 19. ANOVA table for nitrogen content. ANOVA DF Nitrogen Content (kg N ha 1 ) p value Year (Y ) 2 <.0001 Grass (G) 1 <.0001 G*Y 2 <.0001 N so urce (N) 7 0.0016 N*Y 14 0.0024 N *G 7 0.1811 N *Y *G 14 0.6391 Table 3 20. The effect of turfgrasses on nitrogen content in 2008, 2009, and 2010. Turfgrasses 2008 2009 2010 kg N ha 1 St. Augustinegrass 0.73 1.21 0.41 Zoysiagrass 1.30 1.06 1.18 Con trast SA vs. ZO *** NS *** ANOVA DF p value Grass 1 <.0001 0.3162 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SA= St. Augustinegrass, ZO= Zoysiagrass. = Single degree contrasts per formed at the alpha level 0.05.

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79 Table 3 21 The effect of N sources on nitrogen content in 2008, 2009, and 2010. Treatment 2008 2009 2010 kg N ha 1 Control 0.33 0.13 0.04 AN 1.58 1.83 1.00 Urea 1.51 1.54 1.03 SCU1 1.54 1.91 0.87 SCU2 0.98 1.18 1.04 PCU1 0.61 0.88 0.97 PCU2 0.64 0.87 0.76 Biosolid 0.92 0.71 0.66 Contrasts Control vs. Others *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX ** ** NS Soluble vs. BS NS ** NS Soluble vs. MIX NS SCUMIX vs. PCUMIX NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source 7 0.0399 0.0010 0.0021 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: Others= urea, ammonium nitrate, sulfur coated urea 1, sulfur coated urea 2, polymer coated urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 an d polymer coated urea 2 grouped; So luble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts per formed at the alpha level 0.05.

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80 Table 3 22. The effect of turfgrasses an d N sources on nitrogen content by fertilizer cycle in 2008, 2009, an d 2010. Treatment Nitrogen Content 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC2 kg N ha 1 Control 0.33 0.33 0.25 0.03 0.16 0.10 0.05 AN 1.65 1.51 0.77 2.00 3.53 1.01 2.61 Urea 1.86 1.17 0.94 1.48 2.64 1.12 2.32 SCU1 1.80 1.28 0.72 2.17 3.56 1.18 2 .15 SCU2 1.10 0.86 0.96 2.78 2.00 0.98 2.12 PCU1 0.37 0.84 0.47 0.28 1.61 1.17 1.77 PCU2 0.31 0.98 0.68 0.24 1.30 1.26 1.62 Biosolid 0.98 0.86 0.62 0.26 1.42 0.55 1.30 Contrasts Control vs. Others NS ** ** ** ** *** Soluble vs. SCUMIX NS N S NS NS NS NS NS Soluble vs. PCUMIX ** NS NS *** NS Soluble vs. BS NS NS NS ** NS Soluble vs. MIX NS NS ** NS SCUMIX vs. PCUMIX NS NS ** NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS Turfgrasses St. Augustinegrass 0.66 0.79 0. 33 0.74 2.47 1.28 1.00 Zoysiagrass 1.43 1.16 1.02 1.07 1.59 0.56 2.48 Contrast SA vs. ZO *** *** NS *** *** ANOVA DF p value N source (N) 7 0.0303 0.0759 0.1922 0.0002 0.0039 0.0698 0.0009 Grass (G) 1 0.0004 0.0251 0.0005 0.0662 0.0312 <.0001 < .0001 N*G 7 0.3449 0.9584 0.9267 0.6016 0.5075 0.2020 0.1212 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to Augu st October, *FC2 2008 correspond to October December.

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81 Table 3 23. The response of N sour ces by the fertilizer cycle (FC) in St. Augustinegrass nitrog en content In FC1, 3, and 4 in 2010. Treatment St. Augustinegrass Nitrogen Content 2010 FC1 FC3 FC4 kg N ha 1 Control 0.03 0.06 0.002 AN 0.43 1.09 0.10 Urea 0.47 0.97 0.06 SCU1 0.23 0.77 0.05 SCU2 0.28 0.72 0.05 PCU1 0.15 0.79 0.07 PCU2 0.09 0.73 0.05 Biosolid 0.04 0.31 0.008 Contrasts Control vs. Others ** ** Soluble vs. SCUMIX NS N S Soluble vs. PCUMIX *** NS NS Soluble vs. BS *** ** ** Soluble vs. MIX *** SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N source (N) 7 0.0016 0.0118 0.0207 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatmen t code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and U rea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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82 Table 3 24. The response of N sour ces by the fertilizer cycle (FC) in zoysiagrass nitrog en content In FC1, 3, and 4 in 2010. Treatment Zoysiagrass Nitrogen Content 2010 FC1 FC3 FC4 kg N ha 1 Control 0.01 0.12 0.01 AN 0.65 1.85 0.29 Urea 0.62 2.32 0.43 SCU1 0.58 2.00 0.28 SCU2 0.87 2.75 0.52 PCU1 0.68 2.70 0.6 5 PCU2 0.27 2.05 0.51 Biosolid 0.36 2.14 0.44 Contrasts Control vs. Others *** *** ** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX NS NS NS Soluble vs. BS NS NS NS Soluble vs. MIX NS NS NS SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS N S NS NS ANOVA DF p value N source (N) 7 0.0022 0.0080 0.0278 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to Aug ust October, *FC2 2008 correspond to October December.

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83 Table 3 25. ANOVA table for leaf tissue nitrogen concentration. ANOVA DF Leaf Tissue N Concentration (g N kg 1 DM) p value Year (Y ) 2 <.0001 Grass (G) 1 <.0001 G*Y 2 0.1444 N source (N) 7 <.000 1 N*Y 14 <.0001 N *G 7 0.1674 N *Y *G 14 0.2920 Table 3 26. The effect of N sources on leaf tissue nitrogen concentration rate in 2008, 2009, and 2010. Treatment 2008 2009 2010 g N kg 1 DM Control 14.46 13.98 14.13 AN 21.66 25.74 31.33 Urea 21.35 2 5.18 30.65 SCU1 20.61 26.82 30.91 SCU2 19.68 22.88 30.44 PCU1 17.63 23.47 30.74 PCU2 18.74 22.75 28.72 Biosolid 17.26 22.13 27.74 Contrasts Control vs. Others *** *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX *** NS Soluble vs. BS *** ** NS Soluble vs. MIX *** NS SCUMIX vs. PCUMIX NS SCUMIX & PCUMIX vs. BS NS NS ANOVA DF p value N source 7 <.0001 <.0001 <.0001 NS, *,**,***, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: Others= urea, ammonium nitrate, sulfur coated urea 1, sulfur coated urea 2, polymer coated urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur c oated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped ; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts per formed at the alpha level 0.05.

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84 Table 3 27. The effect of turfgrasses and N sources on shoot growth rate by fertilizer cycle in 2008, 2009, and 2010. Treatment Leaf Tissue Nitrogen Concentration 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC4 g N kg 1 DM 1 Control 15.16 13.76 13.1 0 15.45 13.29 14.08 14.90 AN 20.40 22.93 22.93 22.26 27.03 30.75 27.26 Urea 19.93 22.77 22.77 21.76 25.49 30.72 26.42 SCU1 19.58 21.65 21.65 23.78 28.79 33.05 25.98 SCU2 18.00 21.36 21.36 21.63 21.07 27.48 29.99 PCU1 16.91 18.35 16.82 21.75 20.76 34.5 5 29.36 PCU2 17.38 20.10 20.10 19.08 20.25 31.56 26.89 Biosolid 16.12 17.95 17.95 18.87 20.47 31.22 24.72 Contrasts Control vs. Others ** ** ** *** *** *** Soluble vs. SCUMIX NS NS NS NS NS NS NS Soluble vs. PCUMIX NS NS ** NS NS Solub le vs. BS NS NS NS NS NS Soluble vs. MIX NS NS NS NS NS SCUMIX vs. PCUMIX NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS Turfgrasses St. Augustinegrass 16.12 18.20 17.65 21.96 20.24 28.57 24.87 Zoysiagrass 19.86 21.51 21.51 19.18 24.05 29.79 25.75 Contrast SA vs. ZO *** ** ** ** NS NS ANOVA DF p value N source (N) 7 0.1200 0.0654 0.0192 0.0244 0.0002 <.0001 <.0001 Grass (G) 1 <.0001 0.0267 0.0069 0.0070 0.0077 0.2459 0.1976 N*G 7 0.0573 0.4198 0.5331 0.2278 0.7237 0 .4570 0.9891 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha le vel 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October Decem ber.

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85 Table 3 28. The response of N sour ces by the fertilizer cycle (FC) in St. Augustinegrass leaf tissue nitrogen concentration In FC1, 2, and 3 in 2010. Treatment St. Augustinegrass Leaf Tissue Nitrogen Concentration 2010 FC1 FC2 FC3 g N kg 1 DM Control 13.22 16.34 13.05 AN 38.73 35.14 30.26 Urea 35.60 31.10 28.30 SCU1 37.99 33.96 30.45 SCU2 31.33 30.92 26.80 PCU1 31.25 26.66 27.30 PCU2 29.00 28.26 27.13 Biosolid 27.23 26.41 24.37 Contrasts Control vs. Others *** *** *** Soluble vs SCUMIX NS NS NS Soluble vs. PCUMIX *** ** NS Soluble vs. BS *** ** Soluble vs. MIX *** SCUMIX vs. PCUMIX NS SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N source (N) 7 <.0001 <.0001 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0 .001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coate d urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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86 Table 3 29. The response of N sour ces by the fe rtilizer cycle (FC) in zoysiagrass leaf tissue nitrogen concentration In FC1, 2, and 3 in 2010. Treatment Zoysiagrass Leaf Tissue Nitrogen Concentration 2010 FC1 FC2 FC3 g N kg 1 DM Control 13.26 16.85 13.03 AN 30.75 35.48 29.75 Urea 32.75 33.55 32.77 SCU1 31.25 33.60 30.97 SCU2 34.84 34.05 33.64 PCU1 33.92 35.39 32.99 PCU2 31.14 34.45 38.65 Biosolid 31.11 33.62 31.99 Contrasts Control vs. Others *** *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX NS NS NS Soluble vs. BS NS NS NS Soluble vs. MIX NS NS NS SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source (N) 7 <.0001 <.0001 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur co ated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Solubl e= Ammonium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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87 Table 3 30. ANOVA table for root weight, root surface area, and root volume. ANOVA DF Root Weight (kg DM m 3 soil) R oot Surface Area (cm 2 cm 3 soil) Root Volume (cm 3 cm 3 soil) p value Sampling (S) 2 <.0001 <.0001 <.0001 Grass (G) 1 <.0001 0.0029 <.0001 S*G 2 0.7957 0.3495 0.0999 N source (N) 7 0.2092 0.4777 0.7867 N* S 14 0.9866 0.9676 0.3702 N*G 7 0.6685 0.94 27 0.5950 N*G*S 14 0.9783 0.8665 0.7828 Table 3 31. The effect of turfgrasses and sampling date on root weight root surface area and root volume in 2010. Turfgrasses Root Weight (kg DM m 3 soil) Root Surface Area (cm 2 cm 3 soil) Root Volume (cm 3 cm 3 s oil) St. Augustinegrass 4.31 1.01 0.23 Zoysiagrass 2.76 0.85 0.14 Contrast SA vs. ZO *** ** *** Sampling Date May 12 4.45 0.97 0.20 July 12 3.95 1.35 0.27 October 12 2.21 0.48 0.09 Contrasts May 12 vs. July 12 NS *** *** May 12 vs. Oct ober 12 *** *** *** July 12 vs. October 12 *** *** *** ANOVA DF p value Sampling 2 <.0001 <.0001 <.0001 Grass 1 <.0001 0.0022 <.0001 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 ; SA= St. Augustinegrass, ZO= Zoysiagrass. = Single degree contrasts performed at the alpha level 0.05. of 3 root cores per plot per grass average over 3 sampling events

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88 Table 3 32. ANOVA table for length density. ANOVA DF Root Length Density (cm 3 cm 3 soil) p value Sampling (S) 2 <.0001 Grass (G) 1 0.0365 S*G 2 <.0001 N source (N) 7 0. 3585 N* S 14 0.8243 N*G 7 0.7491 N*G*S 14 0.8516 Table 3 33. The effect of turfgrasses on root length density in May 12, July 12, and October 12 in 2010. Turfgrasses Root Length Density (cm 3 cm 3 soil) May 12 July 12 October 12 St. Augustinegrass 4.93 7.14 3.49 Zoysiagrass 4.53 9.69 3.13 Contrast SA vs. ZO NS *** NS ANOVA DF p value Grass 1 0.5665 <.0001 0.4798 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 ; SA= St. Augustinegrass, ZO= Zoysiagrass. RSA= Root surface area, RV= Root volume, RLD= Root length density. = Single degree contrasts performed at the alpha level 0.05. per plot per grass average over 3 sampling events

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89 Table 3 34. The effect of N sources and turfgrass es on root weight, root surface area, root volume, and root length density form 0 to 15 cm depth in May 12, July 12, and October 12 in 2010. Treatments May12 July 12 October 12 RW RSA RV RLD RW RSA RV RLD RW RSA RV RLD Control 6.56 1.49 0.22 7.58 5.74 1.24 0.22 8.45 3.76 0.65 0.11 4.99 AN 7.27 1.51 0.33 8.13 6.53 1.46 0.35 8.03 2.05 0.82 0.17 5.03 Urea 6.39 1.62 0.33 8.67 5.75 1.38 0.26 8.91 3.02 0.62 0.12 3.87 SCU1 7.72 1.62 0.31 6.98 6.27 1.37 0.29 8.10 3.58 0.71 0.11 5.82 SCU2 7.75 1.67 0.35 8.15 6.40 1.25 0.26 7.82 3.48 0.70 0.10 5.90 PCU1 7.11 1.60 0.40 7.41 4.98 1.23 0.23 8.23 3.08 0.61 0.11 4.48 PCU2 6.57 1.60 0.25 8.49 6.22 1.42 0.28 9.23 2.58 0.73 0.11 5.85 Biosolid 6.55 1.54 0.20 7.88 7.17 1.43 0.29 8.55 3.33 0.85 0.17 5.55 Contrasts CT vs. ALL NS NS NS NS NS NS NS NS NS NS NS NS SS vs. SCUX NS NS NS NS NS NS NS NS NS NS NS NS SS vs. PCUX NS NS NS NS NS NS NS NS NS NS NS NS SS vs. BS NS NS NS NS NS NS NS NS NS NS NS NS SS vs. MIX NS NS NS NS NS NS NS NS NS NS NS NS SCU X vs. PCUX NS NS NS NS NS NS NS NS NS NS NS NS CRX vs. BS NS NS NS NS NS NS NS NS NS NS NS NS Turfgrasses SA 7.35 1.54 0.33 7.05 6.64 1.38 0.32 7.10 3.51 0.73 0.14 4.88 ZO 6.63 1.63 0.27 8.53 5.62 1.32 0.22 9.72 2.71 0.69 0.11 5.49 Contras t SA vs. ZO NS NS *** NS NS ** *** NS NS NS NS ANOVA DF p value N source (N) 7 0.8973 0.2423 0.8575 0.2297 0.7552 0.7043 0.3384 0.4457 0.5410 0.7728 0.3853 0.6339 Grass (G) 1 0.1934 0.2765 0.0225 <.0001 0.1188 0.4630 0.0016 <.0001 0.0773 0.5185 0.0973 0.3523 N*G 7 0.9442 0.1643 0.3425 0.2212 0.6928 0.6158 0.6885 0.4392 0.5506 0.2454 0.1259 0.7914 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 RW: Root weight (kg DM m 3 soil); RSA: Root surface area (cm 2 cm 3 soil); RV: Root volume (cm 3 cm 3 soil); RLD: Root length density (cm 3 cm 3 soil). Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 an d sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped. = Single degree contrasts performed at the alpha level 0.05. ss average over 3 sampling events

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90 Table 3 35. The effect of N sources and turfgrasses on root weight, root surface area, root volume, and root length density form 15 to 30 cm depth in May 12, July 12, and October 12 in 2010. Treatments May12 July 12 Oc tober 12 RW RSA RV RLD RW RSA RV RLD RW RSA RV RLD Control 1.78 0.37 0.07 1.31 1.46 1.24 0.22 8.61 1.30 0.25 0.05 1.53 AN 0.78 0.34 0.06 1.16 1.69 1.42 0.30 8.73 1.66 0.23 0.05 1.26 Urea 2.19 0.47 0.16 1.95 1.55 1.38 0.26 8.73 1.22 0.27 0.06 1.62 SCU 1 1.65 0.38 0.08 1.22 1.77 1.37 0.29 8.11 2.20 0.30 0.07 1.71 SCU2 1.74 0.49 0.15 1.03 3.23 1.25 0.26 7.82 1.25 0.28 0.06 1.53 PCU1 1.54 0.38 0.07 1.29 1.28 1.28 0.28 7.53 0.66 0.18 0.03 1.32 PCU2 1.27 0.39 0.09 1.37 1.12 1.42 0.28 9.23 1.28 0.22 0.05 1 .30 Biosolid 1.34 0.36 0.07 1.05 2.02 1.43 0.29 8.55 0.92 0.19 0.03 1.20 Contrasts CT vs. ALL NS NS NS NS NS NS NS NS NS NS NS NS SS vs. SCUX NS NS NS NS NS NS NS NS NS NS NS NS SS vs. PCUX NS NS NS NS NS NS NS NS NS NS NS NS SS vs. BS N S NS NS NS NS NS NS NS NS NS NS NS SS vs. MIX NS NS NS NS NS NS NS NS NS NS NS NS SCUX vs. PCUX NS NS NS NS NS NS NS NS NS NS NS NS CRX vs. BS NS NS NS NS NS NS NS NS NS NS NS NS Turfgrasses SA 3.16 0.62 0.19 2.82 3.02 1.37 0.31 7.17 2.20 0.40 0.09 2.10 ZO 0.67 0.07 0.01 0.53 0.51 1.33 0.23 9.66 0.43 0.08 0.01 0.77 Contrast SA vs. ZO *** *** *** *** *** NS *** *** *** *** *** ANOVA DF p value N source (N) 7 0.3378 0.3307 0.2764 0.1011 0.4165 0.8824 0.9180 0.2488 0.4264 0. 6296 0.4768 0.8849 Grass (G) 1 <.0001 <.0001 <.0001 <.0001 <.0001 0.6411 0.0121 <.0001 <.0001 <.0001 <.0001 <.0001 N*G 7 0.0984 0.0525 0.0529 0.0567 0.3599 0.7493 0.8830 0.3022 0.4219 0.4674 0.4403 0.6154 NS,* **, = P>0.05, P<0.05, P<0.01, P<0.001 RW: Root weight (kg DM m 3 soil); RSA: Root surface area (cm 2 cm 3 soil); RV: Root volume (cm 3 cm 3 soil); RLD: Root length density (cm 3 cm 3 soil). Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammonium nitrate and Urea grouped. = Single degree contrasts performed at the alpha level 0.05. average over 3 sampling events

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91 Figure 3 1 Average rainfall (mm), maximum and minimum soil temperature (C) per month in 2008.

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92 Figure 3 2 Aver age rainfall (mm), maximum and minimum soil temperature (C) per month in 2009.

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93 Figure 3 3 Average rainfall (mm), maximum and minimum soil temperature (C) per month in 2010.

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94 Figure 3 4 Air temperature (C) and solar radiation (w/ m2) during 2008 2009, and 2010

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95 CHAPTER 4 EFFECT OF NITROGEN S OURCE ON MULTISPECTR AL REFLECTANCE AND CHLOROPHYLL INDEX IN ST. AUGUSTINEGRAS S AND ZOYSIAGRASS Turfgrass quality evaluations are used in turfgrass research as a standard for assessing response to treatments ( Trenholm et al. 1999). Quality is influenced by many factors, including visual factors such as shoot density, texture, uniformity, color, growth and smoothness (Turgeon, 2005). Turfgrass quality has to be evaluated according to the function of the grass The principal quality characteristics for a lawn grass es are high shoot density, uniformity, and color (Turgeon, 2005) The response of turfgrass quality and color to nitrogen (N) sources ha s been evaluated on a scale from 1 to 9, with 9 being highest qua lity and 1 being poorest. A rating of 5.5 or above is generally considered acceptable (National Turfgrass Evaluation Program, 2011). Q uality evaluations in turfgrass are often correlated with non subjective variables such as leaf tissue N concentration, yi eld, chlorophyll index or concentration, and multispectral reflectance (MSR) values and ratios M ultispectral reflectance ha s been used to assess plant light reflectance at various wavelengths of light energy T he percentage of light not reflected is eithe r absorbed by the plant or transmitted downward to the soil surface Because of the dense canopies formed by healthy turfgrass, the portion of the spectral energy attributable to transmittance is negligible. Leaf reflectance in the visible wavelength is co rrelated with the concentration of leaf pigments, particularly chlorophyll ( Gitelson and Merzlyak, 1994) R eflectance values and indices have been highly correlated with photosynthetic ally active radiation (PAR) leaf area index (LAI) and plant response t o stress (Trenholm. et al, 1999). Wavelengths in the visible ranges (400 700 nm) can be absorbed by plant pigments and reflectance is very low due to absorption by chlorophyll

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96 (Gitelson and Merzlyak, 1994). Some factors that can affect plant canopy reflect ance include cell structure, water content, and pigment concentration of leaf tissue (Maas et al., 1989). P lants under stress situations typically show decrease d reflectance in the near infrared (NIR) spectral region (760 810 nm). There may also be an in crease in reflectance in the red spectral region (647 760 nm) due to a decrease in chlorophyll content (Guyot, 1990). In the infrared region (IR) (760 2500 nm), energy is absorbed and produc es vibrational frequencies and overtones which is detectable in th e NIR region (Malley et al., 2000). These changes in the spectral reflectance may indicate changes in plant growth or physiological status (Carter and Miller, 1994). Indices developed from spectral data have been used to determine plant health status. Norm alized difference vegetation index (NDVI) is defined as the NIR minus visible reflectance divided by NIR plus visible reflectance ( R 930 R 660 ) / ( R 930 + R 660 ) .It has been shown to be well correlated with PAR (Asrar et al., 1984) Leaf area index is define d as the reflectance in the NIR range divided in the red range (IR/R) ( R 930 / R 660 ) and has been associated with biomass (Daug h try et al., 1992). In turfgrass this may be assessed as canopy density (Trenholm et al., 1999). Several researche r s have been dem onstrated the utility of multispectral reflectance Trenholm et al. (1999) demonstrated that reflectance at 661 and 813 nm, as well as indices NVDI, IR/R (LAI), Stress 1, and Stress 2 were highly correlated with visual turf quality, shoot density, and shoo t tissue injury in seashore paspalum ( Paspalum vaginatum Swartz) and hybrid bermudagrass ( Cynodon dactylon L. x C. transvaalensis Burtt Davy).Water stress in common bermudagrass (Cynodon dactylon

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97 L.) was shown to have lower NDVI (Sonmez et al., 2008). Plots under reduced water stress had higher NDVI values (Sonemz et al. 2008). Indices such as Stress 2 (computed as R 706 / R 813 ) had a strong negative association with color and quality in seashore paspalum and hybrid bermudagrass ( Trenholm et al. 1999 ). There was a limited association between Stress1 (computed as R 706 / R 760 ) and color and quality). Kruse et al. (2006) reported that regressi ng NDVI, Stress 1, and Stress 2 against N concentrations yielded better results when there were distinct differences in N c oncentration between N rates in creeping b entgrass ( Agrostis stolonifera L.) The authors concluded that NDVI might be better suited for determining the relative N status of turfgrass plants when compared to a well fertilized control. Measurements of c hlor ophyll i ndex (CI) may also be used to predict plant physiological response s Chlorophyll concentration may be considered a measure of plant vitality or as an indirect measure of turf color (Pocklington et al., 1974). Blackmer et al. (1994) reported that re flectance at 550 nm provide a stronger relationship with both leaf N concentration and chlorophyll meter readings than chlorophyll meter and leaf N concentration in corn ( Zea mays L.). The Field Scout CM1000Chlorophyll Meter (Spectrum Technology, Plainfiel d, IL) uses ambient and reflected light at 700nm and 840 nm to calculate a relative CI It senses light at wavelengths of 700 and 840 nm to estimate the quantity of chlorophyll in leaves. The ambient and reflected light at each wavelength is measured. Chlo rophyll a absorbs light at 700 nm and, as a result, the reflection of that wavelength from the leaf is reduced compared to the light reflected at 840 nm. W avelength s of 840 nm are unaffected by leaf chlorophyll content and serve as an indication of how mu ch light is

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98 reflected due to leaf physical characteristics such as the presence of a waxy or hairy leaf surface. ( www.specmeters.com ). This instrument has been used by multiple researchers in warm season turfgrass. Sharma (2009) observed that the CI increased as N rate increased in St. Augustinegrass in a glasshouse study. The CI was highest when the turf received 98 kg N ha 1 in comparison with 24 and 73 kg N ha 1 Rodriguez and Miller (2000) described the relations hip of CI with chlorophyll content (g kg 1 fresh tissue) (r 2 =0.79) and visual quality, and total Kjeldahl N (TKN) (r 2 =0.71) in a gl asshouse experiment on Floratam St. Augustinegrass. Correlations were lower in a field study conducted on Fl oralawn (r 2 =0.53) Floratam (r 2 =0.63) and Floratine (r 2 =0.32). The researchers reported low correlations for CI and TKN as well, with values of r 2 = 0.32, 0.54, and r 2 = 0.12 from Floralawn, Floratam, and Floratine St. Augustinegrass, respectively. While there is a growing p ool of research evaluating the effects of instruments such as those discussed on turfgrass research, there are additional potential uses for this field of research. Therefore, the objectives of this study were as follows: To evaluate the effect of N source on multispectral reflectance ratios ND VI LAI, Stress1, and Stress 2 in St. Augustinegrass and zoysiagrass. To evaluate the effect of N source on CI in St. Augustinegrass and zoysiagrass. To determine a relationship between qualitative measurements (visua l quality and color) with quantitative measurements such as growth rate and N concentration in St. Augustinegrass and zoysiagrass. To determine the utility of MSR measurements for correlating qualitative and quantitative measurements. We formulated the fo llowing hypothesis to test: Indices NDVI a nd LAI will increase with soluble and sulfur coated N sources, and Stress 1 and Stress 2 will decrease values with soluble and sulfur coated sources.

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99 Higher CI values will be achieve d with soluble and sulfur coated N sources. Materials and Methods Location and Experimental Site The research was conducted at the G.C. Horn Turfgrass Research Facility at the Plant Science Research and Education Unit Citra, FL. from July 2008 through November 2010 Turfgrasses evaluate d were Floratam St. Augustinegrass and Empire z oysiagrass, both of which were established as sod in 2005. The soil type was Tavares sand (Hyperthermic Uncoated Typic Quartzipsamments), with a pH of 6.8 and organic matter content of 1.3 % Exper imental pl ots measured 4.0 m x 4 .0 m Treatment s Treatments are listed in Table 1. Six of the 8 N treatments were applied at a rate of 49.0kg N ha 1 in 4 equally split applications throughout the growing season. One of the treatments was applied at a rate of 98.0 k g ha 1 twice a year. In 2008, treatments were applied on 24 July and 24September. In 2009, treatments were applied on17April, 17June, 17Augustand 17 October. In 2010, treatments were applied on 21April ,21 J une, 20July and 19 October. Granular N was applied by hand in two directions to each plot to assure uniform plot coverage. Irrigation was applied at a rate of 6.4 mm immediately after every treatment application Response Variables All turfgrass visual evaluations were made on a biweekly basis. In 2008, e valuations were conducted from 29 July through 17 October. In 2009, evaluations were conducted from 6 March through 26 November and in 2010 evaluations were conducted from 3 March through 13 November. Turfgrass quality ratings were measured on a scale from 1 9, where 1= dead, brown turf and 9= optimal, green turf. Acceptable

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100 turfgrass quality was considered 5.5 Color ratings were measured with the same scale, with 1 representing completely chlorotic turf and 9 representing a deep green color. Acceptable tur fgrass color was 5.5. A chlorophyll meter (CM 1000) (Spectrum Technologies, Inc., Plainfield, IL) was used to determine a measure of CI as determined by a ratio of reflectance. Measurements were taken holding the meter approximately 1.5 m from the turf can opy. This yielded a circular area of evaluation of approximately 180 cm 2 per measurement. All measurements were taken in full sun between 1100and 1300 h with the meter facing away from the sun. Multispectral reflectance readings (MSR) were measured once a month during the experiment with a Cropscan model MSR 16 radiometer (CROPSCAN, Inc., Rochester, MN). The radiometer was held at 2 m and measured an area of approximately 1 m 2 Reflectance was measured at wavelengths of 450, 550, 660, 694, 710, 760, 835, an d 930 nm. In addition, the following growth and stress indices were evaluated: NDVI (normalized difference vegetation index) growth index computed as ( R 930 R 660 ) / ( R 930 + R 660 ). Best= 1.0. IR/R (leaf area index) growth index computed as R 930 / R 660 Best= highest value. Stress1 index computed as R 710 / R 760 Best= lowest value. Stress 2 index computed as R 710 / R 810 Best= lowest value. Data P resented and Statistical Analysis Data are presented by Fertilizer Cycle (FC), which is defined as the period of approx imately 60 days between each fertilizer application and as annual averages or totals. In 2008, there were two FCs, since the research began in July for that year. There were 4 FCs in both 2009 and 2010. Nitrogen sources were grouped with same release chara cteristics for analysis. Groupings were: SCUMIX (SCU1 and SCU2), PCUMIX (PCU1 and PCU2).

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101 The experimental design was a split plot design with four replications with turfgrass species as whole plots and N treatments as sub plots Data were analyzed with th e mixed model procedure (Proc MIXED ) of the SAS analytical program(SAS I nstitute Inc ., 2009). Repeated measures were used to obtain results for NDVI, LAI, Stress 1 and Stress 2. Analys i s of Variance (ANOVA) determine d differences at the 0.05 significance le vel. The sources of variation were N source, grass and year, and their interactions. Correlation coefficients were calculated using PROC CORR in SAS. Results and Discussion Chlorophyll Index Chlorophyll index varied due to interactions of grass and year, N source and year, and N source and grass (Table 4 1). In 2009, zoysiagrass CI was 266 higher than S t. Augustinegrass index of 251 .The concentration of chlorophyll represented by the CI is related to growth rate and N concentration. Zoysiagrass had greate r growth rate and N concentration in 2009 than St. Augustinegrass as previously discussed in Chapter 3. Higher TKN results in higher CI, which is related to the increased chlorophyll. Chlorophyll index varied due to N source in each of the three years (Tab le 4 3). The control plots had lower CI than treated plots in each year. In 2008, higher CI was obtained from soluble sources (AN and urea) and sulfur coat ed sources, with values of 295, 280 and an average of 273 for SCU, respectively. Lower CI values were obtained from polymer coated source s and Biosolid (average of 223 and 225 respe ctively). There were differences between soluble sources vs. PCUMIX and Biosolid and MIX. SCUMIX had highe r CI than PCUMIX. No differences were obtained from the comparison be tween SCUMIX and PCUMIX vs. Biosolid.

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102 In 2009, CI was again higher from soluble than from Biosolid. There were also differences from SCUMIX vs. PCUMIX and the combination of them vs. Biosolid. In 2010, the only difference between treated plots was from th e combination of SCUMIX and PCUMIX vs. Biosolid. These results can be attributed to the faster N release, which increased N concentration in leaves and produced higher CI values initially. Results were analyzed by FC for each year (Table 4 4). In 2008, s ignificant effects were due to N source only. In FC1, AN and Urea produced higher CI values (335.7 and320.0, respectively) than PCUMIX or BS, with no difference compared to SCU. Results were similar in FC2, except that there were no differences between SCU MIX and PCUMIX. Again these results are related to the timing of N release between the various products. In 2009, all FCs differed due to N source and in FC2, 3 and 4, there were also differences due to grass (Table 4 4). Results of N sources were very sim ilar to 2008, with highest values from soluble sources. In FC1 and 2, soluble sources had significantly higher values than PCUMIX, BS, and MIX. Sulfur coated ure a sources also had higher values than PCUMIX in FC 1. Polymer coated urea had an intermediate a nd long term N release as indicated by the CI increase over time, similar to the response of SCUMIX. Biosolid had lower values than the controlled release sources. In FC3, the combination of PCUMIX and SCUMIX was significantly higher than BS. In FC4, there were no differences between any plots receiving treatments, but all treated plots were higher than untreated. The faster response from soluble sources and slow to intermediate response from PCUMIX and BS produced differences in CI, which may indicate that more fertilization applications are needed to produce CI values comparable

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103 to s oluble sources. Rodriguez and Miller (2000) found a strong relationship between visual quality, which includes color, and CI, with an r 2 of 0.79 in St. Augustinegrass. Where di fferences occurred due to grass in 2009, higher values were obtained in zoysiagrass. In 2010, significant N source effects were observed during the 4 FCs, and effects due to grass were observed only in FC1 and 2. Zoysiagrass values were higher than St. Aug ustinegrass in FC1 and 2. In all FCs, control plots had lower values than any treated plots. In FC1 and 4, there were no differences between any treated plots. In FC2, SCUMIX and PCUMIX were higher than BS and in FC3, soluble sources had higher values than BS. Multispectral Reflectance The ANOVA indicated that there were interactions of N source and grass at wavelengths 550, 660, 694 and for indices Stress 1, Stress 2 and LAI (Table 4 5). There was an interaction of grass and year at wavelengths 550 and 994 and for the LAI ratio. L eaf area index of zoysiagrass was higher than St. Augustinegrass in 2008 (7.9 and 7.4 respectively) and in 2009 (10.8 and 10.3) (Table 4 6). That indicates that higher density was produced by zoysiagrass, similar to growth rate res ponses of zoysiagrass. It is possible that higher density allowed more light absorption, thus producing an increase in biomass. Trenholm et al. (1999) demonstrated that LAI was highly correlated with shoot density. The interaction of N source and year in L AI showed no significant differences in any of the years between N sources (Table 4 7). Normalized vegetation index (NDVI) was analyzed by FC (Table 4 8). In 2008 there was a difference between grasses in FC1, with higher values in zoysiagrass. In 2009, th ere were differences due to grass in FC3 and 4, with higher values again in

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104 zoysiagrass. In 2010, significant effects were obtained by grass in FC1, with higher values in zoysiagrass. In FC4, differences occurred due to main effects of N and grass. Again, zoysiagrass had higher NDVI than St. Augustinegrass (0.71 and 0.69 respectively). All treated plots were significantly higher than the untreated plots and soluble sources had higher NDVI than BS in FC4 (0.73 and 0.67 respectively). The NDVI ratio is associ ated with turfgrass quality and N status (Kruse et al.,2006). These higher NDVI values are similar to those found for zoysiagrass quality, color, growth and TKN compared to St. Augustinegrass in this research. Stress 1 values did not differ due to treatmen t effects until FC3 and 4 of 2009, where zoysiagrass again had better values than St. Augustinegrass (Table 4 9). In 2010, there were differences due to main effects of grass in FC1 and grass and N in FC4. Zoysiagrass again had better values where differen ces due to grass occurred. In FC4, stress levels were higher in untreated vs. treated plots and BS showed a significantly higher ratio than soluble sources (0.40 and 0.33) and the combination of SCUMIX and PCUMIX (0.40 and 0.35, respectively). The Stress 2 ratio had similar responses to the Stress 1 ratio (Table 4 10). There were no differences due to treatments in 2008. In 2009, differences due to grass were seen in FC2, 3 and 4, with best responses in zoysiagrass. In 2010, there were responses to main eff ects of N and grass in FC4. As previously seen, best values were seen in zoysiagrass. Treated plots had better values than untreated. Soluble N and the combination of SCUMIX and PCUMIX had better scores than BS. The Stress ratios 1 and 2 have been shown to have a strong negative correlation with visual turf quality and shoot density in turfgrass (Trenholm et al., 1999). Our results indicate that stress 1 and

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105 2 ratios in zoysiagrass consistently had higher values for growth indices and lower values for stres s indices than St. Augustinegrass. The higher visual quality, color, and CI values produced by zoysiagrass were higher than St. Augustinegrass, which resulted in lower stress indices. Biosolids consistently had lower values than the other N sources, indica ting the importance of available N in maintaining a growing, dense stand of grass that is less susceptible to moderate stresses. Leaf area index differed between grasses in FC1 in 2008 (Table 4 11). As seen previously, higher values were in zoysiagrass (8. 5 compared to 7.7 for St. Augustinegrass). In 2009, there were differences due to grass in FC3 and 4, with higher values in zoysiagrass (6.6 vs. 5.7 for FC3 and 7.1 and 6.4 in FC4). In 2010, differences were obtained in FC1 due to grass and in FC4 due to m ain effects of N source and grass. In both FCs, zoysiagrass obtained higher LAI than St. Augustinegrass. Treated plots had better values than untreated plots and soluble N plots had higher values than BS. Leaf area index has been associated with biomass (D aughtry et al., 1992) and is related to the higher density and growth rate seen in zoysiagrass. Trenholm et al. (1999) demonstrated that LAI was highly correlated with shoot density, so these results are not unexpected. Correlation Visual quality and col or had some association with CI (r= 0.54, 0.61) (Table 4 12, Figure 4 1a and b) when averaged over time. Leaf area index and NVDI also had associations with CI (r= 0.54, 0.51) (Figure 4 2). Other variables were not highly correlated. Growth rate had a strong correlation with nitrogen uptake (NU) (r=0.94) (Table 4 13, Figure 4 3), but not with TKN (r=0.15).Rodriguez and Miller (2000) reported an r 2 = 0.79 in a regression between TKN concentration and CI in St Augustinegrass.

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106 Analyzed by turfgrass, St Augustineg rass quality and color had positive correlations with CI (r = 0.62 and 0.69, respectively) (Table 4.14, Figure 4 4a, 4 5a). Visual quality and color likewise were associated positively with NDVI and LAI (r=0.51, 0.52, respectively) (Table 4 17, Figure 4 7a ). Similarly, Sharma (2009) found a strong correlation of color and quality with NDVI in St. Augustinegrass in a greenhouse study. We expected increased LAI would be associated with higher CI due to the increase in density and biomass. The observed correla tion between CI and LAI was r= 0.64 in St. Augustinegrass. Chlorophyll index had some association with NDVI (r= 0.59). Our results agree with Kruse et al. (2006), who with reported regression form NDVI, Stress 1, and Stress 2 against different N concentrat ions who obtained an r 2 = 0.63, 0.63 and 0.68, respectively. Our results showed a poor relationship with the stress indices and NDVI. Growth rate was strongly correlated with NU (Figure 4 7b). Correlations were not as strong in zoysiagrass. There was a sli ght relation ship between visual quality and growth rate and NU and with color and CI (r=0.53) (Table 4 16, Figure 4 8 a and b, Figure 4 9a). As seen in St. Augustinegrass, growth rate was highly correlated with NU (r=0.94) (figure 4 9b). Results of the qua ntitative measurements support the visual and growth data. There were strong associations with growth and visual ratings and the measurements taken here. There were fewer responses to the stress indices.

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107 Table 4 1 ANOVA table for chlorophyll index. ANOVA DF Chlorophyll Index p value Year (Y ) 2 <.0001 Grass (G) 1 0.1021 G*Y 2 0.0031 N source (N) 7 <.0001 N*Y 14 <.0001 N *G 7 0.0032 N *Y *G 14 0.3713 Table 4 2 The effect of turfgrasses on chlorophyll index in 2008, 2009, and 2010. Turfgrasses 200 8 2009 2010 Chlorophyll Index St. Augustinegrass 252 251 237 Zoysiagrass 244 266 243 Contrast SA vs. ZO NS ** NS ANOVA DF p value Grass 1 0.0601 0.0030 0.0854 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SA= St. Augustinegras s, ZO= Zoysiagrass. = Single degree contrasts per formed at the alpha level 0.05.

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108 Table 4 3. The effect of N sources on chlorophyll index in 2008, 2009, and 2010. Treatment 2008 2009 2010 Chlorophyll index Control 195 158 157 AN 295 277 253 Urea 281 28 3 260 SCU1 280 285 248 SCU2 266 283 265 PCU1 225 275 255 PCU2 221 254 252 Biosolid 225 255 234 Contrasts Control vs. Others *** *** *** Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX *** NS NS Soluble vs. BS *** NS Soluble vs. MIX *** NS N S SCUMIX vs. PCUMIX *** NS SCUMIX & PCUMIX vs. BS NS ANOVA DF p value N source 7 <.0001 <.0001 <.0001 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: Others= urea, ammonium nitrate, sulfur coated urea 1, sulfur coated urea 2, po lymer coated urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated ur ea grouped; PCUMIX= polymer coated urea 1 an d polymer coated urea 2 grouped; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts per formed at the alpha level 0.05.

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109 Table 4 4. The effect of turfg rasses and N sources on chlorophyll by fertilizer cycle in 2008, 2009, and 2010. Treatment Chlorophyll Index 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 FC2 FC3 FC4 CI Control 218 17 2 13 6 161 171 18 1 144 171 165 136 AN 33 6 255 240 314 283 286 215 2 52 28 5 26 5 Urea 320 24 2 23 6 326 29 3 300 238 279 27 7 235 SCU1 213 248 231 33 4 296 30 2 22 2 270 26 3 227 SCU2 28 6 245 21 9 32 9 30 3 317 247 288 271 240 PCU1 233 21 7 19 6 295 337 284 2 30 271 268 247 PCU2 207 23 5 182 26 5 308 287 21 5 27 4 2 70 247 Biosolid 248 2 0 2 203 283 27 9 281 216 253 24 4 231 Contrasts Control vs. Others *** *** *** *** *** *** *** *** *** *** Soluble vs. SCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. PCUMIX *** *** *** ** NS NS NS NS NS Soluble vs. BS *** ** ** NS NS NS NS NS Soluble vs. MIX *** ** NS NS NS NS NS NS SCUMIX vs. PCUMIX *** NS ** *** NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS ** NS NS NS NS NS Turfgrasses St. Augustinegrass 275 23 1 20 6 27 2 27 7 265 205 250 260 229 Zoysiagrass 26 6 223 204 3 05 29 1 294 226 26 5 25 1 223 Contrast SA vs. ZO NS NS NS *** ** NS NS ANOVA DF p value N source (N) 7 <.0001 0.0002 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 0.0022 Grass (G) 1 0.1197 0.1036 0.8943 <.0001 0.0171 0.0286 0.0020 0.0469 0.169 9 0.3883 N*G 7 0.1381 0.3982 0.3342 0.2463 0.1155 0.2652 0.5220 0.6283 0.0731 0.2402 NS, * **, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coat ed urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammon ium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, a nd Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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110 Table 4 5. ANOVA table for 450, 550, 660, 694, 710 wavelengths, and NDVI, LAI, stress 1, stress 2 ratios ANOVA DF 550 660 694 NDVI Stress 1 Stress 2 LAI p value Year (Y ) 2 0.0131 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 Grass (G) 1 0.6417 0.4951 0.0945 0.4858 0.0530 0.0004 0.2563 G*Y 2 0.0021 0.0813 0.0307 0.3863 0.0710 0.0693 <.0001 N source (N) 7 <.0001 <.0001 <.0001 <.0001 0.9867 0.9829 <.0001 N*Y 14 0.3071 0.2305 0.1996 0.5284 0.3634 0.3085 0.0008 N *G 7 0.0002 0.0003 0.0002 0.1103 0.0473 0.0355 0.0001 N *Y *G 14 0.3235 0.8794 0.8215 0.9966 0.9744 0.9685 0.5406 NDVI= Normalized difference vegetation index, LAI= Leaf area index.

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111 Table 4 6. The effect of turfgrasses on 550, 694 wavelengths and leaf area index ratio in 2008, 2009, and 2010. Turfgrasses 2008 2009 2010 550 wv 694 wv LAI 550 wv 694 wv LAI 550 wv 694 wv LAI St. Augustinegrass 10.6 9.0 7.4 10.8 10.3 5.8 10.8 10.1 5.9 Zoysiagrass 10.5 9.0 7.9 11.0 10.8 5.5 10.8 10.2 5.9 Contrast SA vs. ZO NS NS ** NS NS NS NS ANOVA DF p value Grass 1 0.5666 0.9057 0.0011 0.1035 0.0322 0.0869 0.9446 0.6631 0.7313 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: SA= St. Augustinegrass, ZO= Zoysiagr ass. LAI= Leaf area index. = Single degree contrasts per formed at the alpha level 0.05.

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112 Table 4 7. The effect of N sources on leaf area index in 2008, 2009, and 2010. Treatment 2008 2009 2010 LAI Control 5.9 4.6 4.8 AN 8.8 5.9 6.3 Urea 8.8 6.0 6.3 S CU1 8.7 5.6 5.9 SCU2 7.6 6.0 6.2 PCU1 7.2 5.9 6.0 PCU2 7.3 5.9 6.0 Biosolid 7.0 5.5 5.7 Contrasts Control vs. Others NS NS NS Soluble vs. SCUMIX NS NS NS Soluble vs. PCUMIX NS NS NS Soluble vs. BS NS NS NS Soluble vs. MIX NS NS NS SCUMIX vs. PCUMIX NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS ANOVA DF p value N source 7 0.8074 0.9963 0.9804 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001Treatment code: Others= urea, ammonium nitrate, sulfur coated urea 1, sulfur coated urea 2, polymer coate d urea 1, polymer coated urea 2, Biosolid; SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 an d polymer coated urea 2 grouped; Soluble= Am monium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. LAI= Leaf area index. = Single degree contrasts per formed at the alpha level 0.05.

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113 Table 4 8. The effe ct of turfgrasses and N sources on normalized vegetation index by fertilizer cycle in 2008, 2009, and 2010. Treatment Normalized Vegetation Index 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 FC2 FC3 FC4 NDVI Control 0.72 0.67 0.50 0.65 0.65 0.64 0.57 0.66 0.67 0.57 AN 0.79 0.76 0.53 0.73 0.71 0.75 0.67 0.72 0.71 0.74 Urea 0.79 0.75 0.54 0.73 0.72 0.75 0.70 0.71 0.71 0.73 SCU1 0.79 0.74 0.50 0.73 0.70 0.73 0.66 0.71 0.69 0.72 SCU2 0.76 0.72 0.57 0.73 0.72 0.72 0.71 0.72 0.68 0.72 PCU1 0.75 0.71 0. 51 0.72 0.73 0.73 0.66 0.71 0.70 0.71 PCU2 0.75 0.72 0.49 0.73 0.72 0.74 0.67 0.71 0.69 0.73 Biosolid 0.75 0.69 0.50 0.72 0.69 0.71 0.66 0.70 0.70 0.67 Contrasts Control vs. Others NS NS NS NS NS NS NS NS NS *** Soluble vs. SCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. PCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. BS NS NS NS NS NS NS NS NS NS Soluble vs. MIX NS NS NS NS NS NS NS NS NS NS SCUMIX vs. PCUMIX NS NS NS NS NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS NS NS NS Turfgrasses St. Augustinegrass 0.75 0.73 0.50 0.72 0.69 0.71 0.64 0.71 0.70 0.69 Zoysiagrass 0.78 0.72 0.53 0.72 0.72 0.73 0.68 0.71 0.69 0.71 Contrast SA vs. ZO *** NS NS NS *** *** NS NS ** ANOVA DF p value N source (N) 7 0.6073 0.9 579 0.9991 0.6233 0.9023 0.5598 0.6299 0.9225 0.9992 0.0008 Grass (G) 1 <.0001 0.5248 0.2428 0.6565 0.0008 0.0105 0.0004 0.9205 0.3954 0.0021 N*G 7 0.2118 0.4736 0.8927 0.6456 0.4260 0.4081 0.5705 0.4049 0.7595 0.1193 NS, *, **, ***, = P>0.05, P<0.05, P <0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= pol ymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammon ium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. NDVI= Normalized vegetation index. = Single degree contrasts performed at the alpha level 0.05. =Me ans of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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114 Table 4 9. The effect of turfgrasses and N sources on stress 1 index by fertilizer cycle in 2008, 2009, and 2010. Treatment Stress 1 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 FC2 FC3 FC4 Stress 1 Control 0.42 0.43 0.59 0.44 0.46 0.43 0.53 0.44 0.42 0.49 AN 0.33 0.32 0.56 0.38 0.41 0.33 0.43 0.39 0.38 0.33 Urea 0.33 0.33 0.56 0.38 0.40 0.33 0.41 0.39 0.39 0.34 SCU1 0.32 0.34 0.58 0.38 0.42 0.35 0.44 0.40 0.41 0.35 SCU2 0.37 0.36 0.51 0.37 0.40 0.36 0.39 0.39 0.42 0.35 PCU1 0.38 0.38 0.59 0.38 0.39 0.34 0.45 0.40 0.40 0.35 PCU2 0.39 0.36 0.60 0.37 0.39 0.33 0.43 0.39 0.40 0.35 Biosolid 0.38 0.39 0.58 0.39 0.41 0.37 0.44 0.40 0.40 0.40 Contrasts Control vs. Others NS NS NS NS NS NS NS NS NS *** Soluble vs. SCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. PCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. BS NS NS NS NS NS NS NS NS NS ** Soluble vs. MIX NS NS NS NS NS NS NS NS NS NS SCUMIX vs. PCUMIX NS NS NS NS NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS NS NS Turfg rasses St. Augustinegrass 0.37 0.36 0.58 0.38 0.43 0.38 0.45 0.40 0.39 0.35 Zoysiagrass 0.36 0.37 0.56 0.39 0.39 0.33 0.43 0.40 0.41 0.39 Contrast SA vs. ZO NS NS NS NS *** *** NS NS *** ANOVA DF p value N source (N) 7 0.4561 0.8707 0.9982 0.660 7 0.9184 0.4339 0.5583 0.9565 0.9998 <.0001 Grass (G) 1 0.5089 0.3488 0.4124 0.2213 0.0002 <.0001 0.0305 0.4129 0.2098 <.0001 N*G 7 0.1163 0.2048 0.9441 0.7123 0.3563 0.1274 0.7587 0.5408 0.9599 0.1146 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001 T reatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammon ium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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115 Table 4 10. The effect of turfgrasses and N sources on str ess 2 index by fertilizer cycle in 2008, 2009, and 2010. Treatment Stress 2 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 FC2 FC3 FC4 Stress 2 Control 0.39 0.40 0.56 0.43 0.44 0.41 0.51 0.42 0.40 0.47 AN 0.31 0.30 0.52 0.36 0.39 0.31 0.40 0.38 0.37 0 .31 Urea 0.30 0.31 0.52 0.36 0.38 0.31 0.39 0.38 0.37 0.32 SCU1 0.30 0.31 0.55 0.36 0.40 0.34 0.41 0.38 0.39 0.33 SCU2 0.34 0.33 0.48 0.35 0.38 0.34 0.37 0.37 0.40 0.33 PCU1 0.35 0.35 0.56 0.36 0.37 0.33 0.42 0.38 0.38 0.34 PCU2 0.36 0.33 0.57 0.36 0. 37 0.32 0.41 0.37 0.38 0.32 Biosolid 0.35 0.36 0.55 0.37 0.39 0.34 0.42 0.38 0.38 0.38 Contrasts Control vs. Others NS NS NS NS NS NS NS NS NS *** Soluble vs. SCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. PCUMIX NS NS NS NS NS NS NS NS N S NS Soluble vs. BS NS NS NS NS NS NS NS NS NS ** Soluble vs. MIX NS NS NS NS NS NS NS NS NS NS SCUMIX vs. PCUMIX NS NS NS NS NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS NS NS Turfgrasses St. Augustinegrass 0.34 0.33 0.54 0.38 0. 41 0.36 0.42 0.38 0.37 0.38 Zoysiagrass 0.34 0.34 0.53 0.36 0.37 0.31 0.41 0.38 0.39 0.32 Contrast SA vs. ZO NS NS NS *** *** NS NS NS *** ANOVA DF p value N source (N) 7 0.5035 0.8362 0.9984 0.6290 0.8886 0.4741 0.4345 0.9400 0.9997 <.0001 Grass (G) 1 0.5319 0.1089 0.5978 0.0324 <.0001 <.0001 0.0834 0.1386 0.1067 <.0001 N*G 7 0.1110 0.1890 0.9659 0.7396 0.3783 0.1264 0.7858 0.5614 0.9068 0.1199 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= s ulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid ; Soluble= Ammon ium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. = Single degree contrasts performed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, F C2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspond to October December.

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116 Table 4 11. The effect of turfgrasses and N sources on leaf area index by fertilizer cycle in 2008, 2009, a nd 2010. Treatment Leaf Area Index 2008 2009 2010 FC1 FC2 FC1 FC2 FC3 FC4 FC1 FC2 FC3 FC4 LAI Control 6.4 5.2 3.2 5.0 4.9 5.3 3.9 5.1 5.6 3.7 AN 9.1 8.2 3.7 6.6 6.0 7.4 5.5 6.4 6.5 6.9 Urea 9.3 8.1 3.8 6.5 6.4 7.5 5.9 6.2 6.5 6.9 SCU1 9.2 7.8 3. 4 6.5 5.9 6.6 5.2 6.2 5.7 6.4 SCU2 8.0 7.0 4.3 6.7 6.5 6.6 6.3 6.3 5.7 6.5 PCU1 7.5 6.6 3.4 6.5 6.8 6.9 5.2 6.1 6.1 6.3 PCU2 7.5 6.9 3.1 6.7 6.6 7.1 5.5 6.2 6.0 6.7 Biosolid 7.5 6.1 3.4 6.3 5.8 6.4 5.3 5.9 6.1 5.2 Contrasts Control vs. Oth ers NS NS NS NS NS NS NS NS NS *** Soluble vs. SCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. PCUMIX NS NS NS NS NS NS NS NS NS NS Soluble vs. BS NS NS NS NS NS NS NS NS NS Soluble vs. MIX NS NS NS NS NS NS NS NS NS NS SCUMIX vs. PCUMIX NS NS NS N S NS NS NS NS NS NS SCUMIX & PCUMIX vs. BS NS NS NS NS NS NS NS NS NS NS Turfgrasses St. Augustinegrass 7.7 6.9 3.4 6.3 5.7 6.4 4.8 6.0 6.2 5.7 Zoysiagrass 8.5 7.0 3.7 6.4 6.6 7.1 5.8 6.1 5.8 6.4 Contrast SA vs. ZO *** NS NS NS *** *** NS NS *** ANOVA DF p value N source (N) 7 0.6532 0.8590 0.9944 0.8441 0.9171 0.9133 0.8130 0.9718 0.9998 0.0070 Grass (G) 1 <.0001 0.7063 0.2014 0.6052 0.0003 0.0102 <.0001 0.8652 0.2707 0.0006 N*G 7 0.2376 0.4083 0.9190 0.5808 0.5360 0.2131 0.9700 0.4377 0.623 1 0.1186 NS, *, **, ***, = P>0.05, P<0.05, P<0.01, P<0.001 Treatment code: SCU1= sulfur coated urea 1; SCU2= sulfur coated urea 2; PCU1= polymer coated urea 1; PCU2= polymer coated urea 2 applied at 98 kg ha 2 every 120 d cycle; SCUMIX= sulfur coated urea 1 and sulfur coated urea grouped; PCUMIX= polymer coated urea 1 and polymer coated urea 2 grouped; BS= Biosolid; Soluble= Ammon ium nitrate and Urea grouped; MIX= SCUMIX, PCUMIX, and Biosolid grouped. LAI= Leaf area index. = Single degree contrasts perform ed at the alpha level 0.05. =Means of 4 evaluations events, average over each 60 d cycle. FC: Fertilizer cycle, FC1: April June, FC2: June August, FC3: August October, and FC4: October December, *FC1 2008 correspond to August October, *FC2 2008 correspon d to October December.

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117 Table 4 12. Pearson correlation matrix of visual quality (VQ), color, and chlorophyll index (CI), with growth rate, nitrogen con centration (TKN), nitrogen content (NC ), and reflectance values during the entire research. Variables P earson Correlation Coefficients VQ Color CI GR TKN N C WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 VQ 1.00 0.90 0.54 0.48 0.36 0.48 0.41 0.37 0.46 0.45 0.33 0.43 0.43 0.40 0.40 Color 0.90 1.00 0.61 0.46 0.39 0.46 0.39 0.40 0. 46 0.45 0.37 0.40 0.42 0.38 0.37 CI 0.54 0.61 1.00 0.46 0.34 0.45 0.42 0.35 0.51 0.49 0.33 0.51 0.54 0.46 0.44 N=640. NVDI= Normalized digital vegetation index, LAI= Leaf area index. Table 4 13. Pearson correlation matrix of growth rate (GR), nitrogen concentration (TKN), and nitrogen content (NC ) with visual quality (VQ), color, chlorophyll index (CI), and reflectance values during the entire research. Variables Pearson Correlation Coefficients VQ Color CI GR TKN NC WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 GR 0.48 0.46 0.46 1.00 0.15 0.94 0.24 0.19 0.35 .035 0.18 0.26 0.32 0.20 0.19 NC 0.36 0.39 0.34 0.15 1.00 0.37 0.14 0.24 0.11 0.12 0.21 0.23 0.19 0.25 0.22 NU 0.48 0.46 0.44 0.46 0.34 0.94 0.24 0.19 0.33 0.33 0.17 0.26 0.29 0.20 0.19 N=640. NVDI= Normalized digital vegetation index, LAI= Leaf area index. Table 4 14. Pearson correlation matrix of visual quality (VQ), color, and chlorophyll index (CI), with growth rate, nitrogen con centration (TKN ), nitrogen content (NC ), and reflectance values during the entire research in St. Augustinegrass. Variables Pearson Correlation Coefficients VQ Color CI GR TK N N C WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 VQ 1.00 0.92 0.62 0.40 0.38 0.41 0.48 0.45 0.54 0.55 0.46 0.51 0.52 0.48 0.49 Color 0.92 1.00 0.69 0.41 0.37 0.40 0.44 0.44 0.53 0.55 0.46 0.49 0.51 0.44 0.45 CI 0.62 0.69 1.00 0.50 0.27 0.47 0.49 0.38 0.60 0.61 0.42 0.59 0.64 0.52 0.52 N=320. NVDI= Normalize d digital vegetation index, LAI= Leaf area index.

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118 Table 4 15. Pearson correlation matrix of growth rate (GR), nitrogen concentration (TKN), and nitrogen content (NC ) with visual quality (VQ), color, chlorophyll index (CI), and reflectance values during th e entire research in St. Augustinegrass. Variables Pearson Correlation Coefficients VQ Color CI GR TK N N C WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 GR 0.40 0.41 0.50 1.00 0.08 0.95 0.31 0.18 0.39 0.40 0.21 0.33 0.38 0.26 0.25 NC 0.37 0.37 0.27 0.08 1.00 0.27 0.18 0.31 0.16 0.18 0.30 0.26 0.20 0.30 0.27 NU 0.41 0.40 0.47 0.95 0.29 1.00 0.31 0.20 0.38 0.38 0.22 0.33 0.36 0.27 0.26 N=320. NVDI= Normalized digital vegetation index, LAI= Leaf area index. Table 4 16. Pearson correlation matrix of visual quality (VQ), color, and chlorophyll index (CI), with growth rate, nitrogen concent ration (TKN), nitrogen content (NC ), and reflectance values during the entire research in zoysiagrass. Variables Pearson Correlation Co efficients VQ Color CI GR TK N N C WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 VQ 1.00 0.85 0.46 0.54 0.30 0.54 0.37 0.33 0.40 0.39 0.31 0.33 0.34 0.34 0.34 Color 0.85 1.00 0.53 0.50 0.39 0.50 0.41 0.42 0.41 0.42 0.39 0.40 0 .33 0.35 0.35 CI 0.47 0.53 1.00 0.42 0.39 0.42 0.40 0.34 0.43 0.41 0.31 0.44 0.45 0.42 0.40 N=320. NVDI= Normalized digital vegetation index, LAI= Leaf area index. Table 4 17. Pearson correlation matrix of growth rate (GR), nitrogen concent rati on (TKN), and nitrogen content (NC ) with visual quality (VQ), color, chlorophyll index (CI), and reflectance values during the entire research in zoysiagrass. Variables Pearson Correlation Coefficients VQ Color CI GR NC NU WV 450 WV 550 WV 660 WV 694 WV 710 NDVI LAI Stress 1 Stress 2 GR 0.54 0.50 0.42 1.00 0.18 0.94 0.22 0.23 0.33 0.35 0.23 0.19 0.27 0.15 0.17 NC 0.31 0.59 0.39 0.18 1.00 0.41 0.12 0.19 0.06 0.08 0.18 0.20 0.17 0.22 0.20 NU 0.54 0.50 0.42 0.94 1.00 0.47 0.23 0.21 0.32 0.34 0.21 0.21 0.25 0.17 0.17 N=320. NVDI= Normalized digital vegetation index, LAI= Leaf area index.

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119 Figure 4 1. The relationship of evaluation variables A) Relationship between visual quality and chlorophyll index and B) color and chlorophyl l index A B

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120 Figure 4 2. The relationship of evaluation variables. A) Relationship betwee n chlorophyll index and NDVI and B) chlorophyll index and LAI. A B

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121 Figure 4 3. The relationship between growth rate a nd nitrogen content

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122 F igure 4 4. The relationship of evaluation variables A) Relationship between visual quality and chlorophyll index and B) visual quality and NDVI in St Augustinegrass. A B

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123 Figure 4 5. The relationship of evaluation variables A) Relationship between co lor and chlorophyll index and B) chlorophyll index and NDVI in St Augustinegrass. A S B

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124 Figure 4 6. The relationship of evaluation variables A) Relat ionship between visual quality and LAI and B) color and LAI in St Augustinegrass. A B

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125 Figure 4 7. The relationship of evaluation variables. A) Relationship between chlorophyll index and LAI and B) growth rate and nitrogen content in St. Augustinegrass. A B

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126 Figure 4 8. The relationship of evaluation variables A) Relationship between visual quali ty and growth rate and B) visual qua lity and nitrogen content in zoysiagrass. A B

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127 Figure 4 9. The relationship of evaluation variables A) Relationship between visual quality and chlorophyll index and B) growth rate and nitrogen content in zoysiagrass A B

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128 CHAPTER 5 SUMMARY AND CONCLUSI ONS Nitrogen (N) is the nutrient required in greatest quantities by turfgrass, promoting vigor, quality, shoot density and color (Bowman et al. 2002). Turf grass responses to nitrogen are increased green color, shoot growt h, shoot density, and root growth In Florida lawns, N fertilization is required to maintain turf health due to the low N retention by soils low cation exchange capacity (CEC), high infiltration rates and poor water holding capa city. However, these soil c onditions make soils vulnerable to nitrate N (NO 3 N) leaching. Nitrogen not taken up by turf has the potential to leach through the soil profile as NO 3 N, as it is not held in the negatively charged soils. In addition, due to these soil characteristics an d possible pollution due to fertilization practices, local ordinances ha ve been imposed in Florida to reduce potential nonpoint source pollution from fertilization practices Since December 31, 2007 every one who fer tilizes a home lawn must comply with a n ew state rule (Department of Agriculture and Consumer Services (DACS), No 4640400, Rule 5E 1.003, 2007 ). The rule regulates N application rates. S low release nitrogen can be applied at 49 kg of N ha 1 per application, while soluble nitrogen can be applied at a rate of 34.3 kg ha 1 per application (Department of Agriculture and Consumer Services (DACS), No 4640400, Rule 5E 1.003, 2007). Florida. There is increasing interest in and Nitrogen fertilizers may be applied from numerous sources, which are classified as quick release or water soluble, controlled release, slow release, or organic N. Florida soils typically

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129 have a limited ability to retain N and therefore require regular additions of N for maintenance of a healthy turfgrass (Sartain and Kruse 2001). The overall objective of this research was to evaluate the response of different N sources on the turfgrass aesthetic appearance and health of Flora tam St. Augustinegrass and Empire research were: To evaluate the response of various N sources on acceptable vis ual turfgrass quality and color in St. Augustinegrass and zoysiagrass. To compare the effect of various N sources on shoot growth, N up take and N tissue concentration. To evaluate differences between the two grasses for shoot growth rate, root dry matter, root volume, root surface area, and root length density. To determinate the effect of nitrogen sources on root dry matter, root volume, root surface area, and root length density. To evaluate the response of N source on chlorophyll index in St. Augustinegrass and Zoysiagrass. To evaluate the response on N source on multispectral reflectance ratios NDV, LAI, Stress1, and Stress 2 in St. Augustinegrass and Zoysiagrass. To determinate a relationship between visual quality and color with growth rate, TKN, N content, chlorophyll index and multispectral reflectance. The first objective of this res earch was to evaluate the response of various N sources on acceptable visual turfgrass quality and color in St. Augustinegrass and zoysiagrass Annual visual quality showed a higher response from soluble sources include AN, and Urea, and also the sulfur co ated urea sources (SCUMIX) during the three years of evaluations. In 2008, N sources in both turfgrasses produced the minimum score of 5.5. In 2009, zoysiagrass produced higher visual quality than St. Augustinegrass (5.6 and 5.2, respectively). No differen ces were observed between

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130 soluble and SCUMIX (6.0 and 5.7 respectively). Soluble sources (6.0) produced higher visual quality than PCUMIX and Biosolid (5.2 and 5.2 respectively). Sulfur coated sources obtained higher visual quality than PCUMIX (5.7 and 5.2 respectively). In 2010, in St. Augustinegrass soluble sources and sulfur coated urea sources (6.2 and 5.8 respectively) produced a higher visual quality than the polymer coated urea and Biosolid (5.5 and 5.1 respectively). On average soluble sources produ ced higher quality scores than PCMUX and Biosolid (6.2, 5.5 and 5.1 respectively). Biosolid did not produce the minimum acceptable visual quality on St. Augustinegrass compared with soluble sources and sulfur coated sources but produce the same respond tha n PCUMIX. In zoysiagrass, all N sources produced good quality regardless to the N sources. Color responses were similar to visual quality. Zoysiagrass produced higher color than St. Augustinegrass in 2008 (6.0 and 5.8, respectively) and 2009 (5.7 and 5.3, respectively). Soluble sources produced better color than PCUMIX in 2008 and 2009 (6.1 and 5.7 for 2008, and 6.0 and 5.5 for 2009). Soluble sources produced higher color than Biosolid in 2009 (6.0 and 5.3 respectively). Sulfur coated sources produced highe r color than PCUMIX in 2008 and 2009. Also the combination of the control release sources produced better color than Biosolid. Soluble sources and SCUMIX produced anual better and faster color standard than PCUMIX and Biosolid. In 2010, in St. Augustinegr ass soluble sources produced better color than PCUMIX and Biosolid, also the combination of the control release sources produce better color than Biosolid. Biosolid produce the poorest color in St. Augustinegrass obtained a score lower than the minimum. In zoysiagrass, color responses were

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131 practically equal form all N sources (6.0 on average). Color was more than the acceptable score regardless to the N source. The second objective was t o compare the effect of various N sources on shoot growth, and TKN. Sol uble sources produced higher shoot growth rate than PCUMIX in 2008 (10.41 and 4.89 kg DM ha 1 d 1 respectively) and 2009 (9.46 and 5.50 kg DM ha 1 d 1 ). Sulfur coated urea sources produced higher growth rate than PCUMIX in 2009. Soluble sources produced hi gher growth rate in 2009 (9.49 and 4.58 kg DM ha 1 d 1) and 2010 (4.48 and 2.93 kg DM ha 1 d 1 ) than Biosolid. During 2010 PCUMIX obtained similar growth rate than soluble sources and SCUMIX which means a long term response due to the higher plain N releas e from the fertilizers. That response agrees with the data observed in visual quality and color. The third objective was t o evaluate differences between the two grasses for shoot growth rate, root dry matter, root volume, root surface area, and root lengt h density. Zoysiagrass produced higher growth rate than St. Augustinegrass in 2008 (8.61 and 5.89 kg DM ha 1 d 1 ) and 2010 (5.25 and 1.94 kg DM ha 1 d 1 ). During the fertilizer cycles zoysiagrass produced higher shoot growth rate than St. Augustinegrass in all FC may be caused to higher density of the grass, higher N rate than the normal applied, and higher TKN. An exception occurred in FC3 and 4 which St. Augustinegrass produced higher growth rate caused by a biotic problem occurred in the plots during th ose cycles reducing substantially the shoot growth rate in zoysiagrass. St. Augustinegrass produced higher RW, RSA, and RV than zoysiagrass in 2010. In addition zoysiagrass produced higher RLD form 0 to 15 cm than St. Augustinegrass (8.53 and 7.05 cm cm 3 ) which may also agree the higher growth rate from zoysiagrass

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132 than St. Augustinegrass. St. Augustinegrass obtained higher RW, RSA, RV, and RLD than zoysiagrass from 15 to 30 cm depth. The fourth objective was t o determinate the effect of nitrogen sources on root dry matter, root volume, root surfac e area, and root length density. Nitrogen sources did not influence root variables regardless of depth or sampling date. The fifth objective was t o evaluate the response of N source on chlorophyll index in St. Au gustinegrass and z oysiagrass. Zoysiagrass obtained higher CI than St Augustinegrass in 2009 (266.1 and 251.1, respectively) which agrees with TKN data in 2009. Soluble sources produced higher CI than PCUMIX and BS in 2008, also SCUMIX CI were higher than PCUMIX. In 2009, PCUMIX CI increase obtained similar values than soluble sources. Biosolid obtained lower CI in 2009 than soluble sources and control release sources. In 2010, only the control release sources obtained higher CI than Biosolid which might b e cause d by the increase in TKN observed in 2010. The responses across fertilizer cycles were similar than TKN as N concentration increase in the turf CI increase over the time. The sixth objective was t o evaluate the response on N source on multispectral reflectance ratios NDV, LAI, Stress1, and Stress 2 in St. Augustinegrass and z oysiagrass. Soluble sources obtained higher NDVI, less Stress 1, less Stress 2, and higher LAI in FC4 in 2010 which is similar than results observed in visual quality and color. Otherwise, the control release sources obtained less Stress 1, less Stress 2 than Biosolid in FC4 in 2010. Zoysiagrass produced higher NDVI, less Stress 1, less Stress 2, and higher LAI than St. Augustinegrass which agrees with results from visual quality, color, shoot growth rate and TKN.

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133 The seventh objective was to dete rmine a relationship between visual quality and color with growth rate, TKN, N content, chlorophyll index and multispectral reflectance. A slight relationship was obtained from CI with vis ual quality and color (r= 0.54 and 0.61, respectively) and with CI and wavelength 660, NDVI and LAI (r=0.51, 0.51 and 0.54, respectively). A strong relationship was found between shoot growth rate and N content. Poor relationships were found with other va riables which were lower than 0.50. Based on the results of this research, the best sources for fertilization of Floratam St. Augustinegrass would be soluble sources and SCUMIX and either of the N sources for Empire zoysiagrass. Soluble sourc es and SCUMIX provide equivalent response s in Floratam St. Augustin egrass and also provide a greater visual quality, color, and greater shoot growth rate, and shoot density. At the same time those sources produced enough TKN in the tissue form the first application prov iding good turf health resulting in less Stress indices and higher NDVI reflectance ratio. Polymer coated sources will achieve good turf stan dards in the long term response Biosolid is not a good source to use in St. Augustinegrass because did not produce good quality and color standards, and also shoot growth rate at all. Despite PCUMIX and BS will not provide good results from the first fertilizer application treatment it will provide sufficient TKN in tissue. In Empire zoysiagrass any of the N sources will provide acceptable results in terms of quality, color, shoot growth rate, sufficient TKN in tissue, and shoot density. Zoysiagrass responded better than St. Augustinegrass to the N sources applied.

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134 LIST OF REFERENCES Angle, J.S. 1985. Effect of cropp ing practices on sediment and nutrient losses from tobacco.Tob Sci. 29:107 110. Asrar, G., M. Fuchs, E.T. Kanemasu, and J.L. Hatfield. 1984. Estimating absorbed photosynthetic radiation and leaf area index from spectral reflectance in wheat. Agron. J. 76:300 306. Beard, J.B. and R.L. Green 1994. The role of turfgrasses in environmental protection and benefits. J. Environ. Qual. 23:1 16. Beard, J.B. 1973. Turfgrass: science and culture. Prentice Hall, Englewood Cliffs, NJ. Blackmer, T.M., J.S. Schepe rs, and G.E. Barvel. 1994. Light reflectance compared with other nitrogen stress measurements in corn leaves. Agron. J. 86:934 938. Bowman, D.C., C.T. Cherney, and T.W. Rufty Jr. 2002. Fate and transport of nitrogen applied to Six Warm Season turfgrasses. Crop Sci. 42:833 841. Bowman, D.C., D.A. Devitt, M.C. Engelke, and T.W. Rufty Jr. 1998. The Effect of Root Architecture on nitrate leaching from Bentgrass Turf. Crop Sci. 38:1633 1639. Brown, K.W, J.C. Thomas, and R.L. Duble. 1982. Nitrogen sources effect on nitrate and ammonium leaching and runoff losses from greens. Agron. J. 74:947 950. Carrow, R.N. 1989. Managing turf for maximum root growth. Golf Course Management. Carrow, R.N. 1997. Turfgrass response to slow release nitrogen fertilizers. Agron. J. 8 9:491 496. Carrow, R.N., D.V. Waddington, and P.E. Rieke. 2001. Turfgrass soil fertility and chemical problems: assessments and management. John Wiley & Sons, NJ. Carter, G.A. and R.L. Miller. 1994. Early detection of plant stress by digital imaging within narrow stress sensitive wavebands. Remote Sens. Environ. 50:295 302. Castillo, M.S., L.E. Sollenberger, J.M.B. Vendrimin i K.R. Woodard J.T. Gilmo ur G.A. Connor Y.C. Newman M.L. Silveira and J.B. Sartain 2011. Municipal biosoloids as an alterna tive nutrient source for bioenergy crops: II. Decompsoition and organic nitrogen mineralization. Agron. J. 102:1314 1320. Christians, N.E. 2007. Fundamentals of turfgrass management. John Wiley & Sons, NJ. Daughtry, C.S.T., K.P. Gallo, N.S. Goward, S.D. Prince, and W.P. Kustas. 1992. Spectral estimates of absor bed radiation and phytomass production in corn soybean canopies. Remo Sens. Environ. 39:141 152.

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135 Departme nt of Agriculture and Consumer S ervices, N o. 4640400, Rule 5E 1.003. 2007. Available at: http://www.dep.state.fl.us/water/nonpoint/ Erickson, J.E. 2001. Comparing Nitrogen Runoff and Leaching between Newly Established St. Augustinegrass Turf and an Alternative Residential Landscape. Crop Sc i. 41:1889 1895. E rickson, J.E., J.L. Cisar, G.H. Snyder, D.M. Park, and K.E. Williams. 2008. Does mixed species landscape reduce inorganic nit r o gen leaching compared to a conventional St. Augustinegrass lawn?. Crop Sci. 48:1596 1594 Flipse, J.R. B.G. K atz, J.B. Lindner, and R. Markel. 1984. Sources of nitrate in groundwater in a sewer housing development, central Long Island, New York. Groundwater 32:418 426. Fuentealba, M.P. 2010. Root development and transpirational response to soil drying of warm sea son turfgrasses specie s. Thesis presented to the University of Florida Graduate School, Gainesville, FL Geron, C.A., T.K. Danneberg, S.J. Traina, T.J. Logan, and J.R. Street. 1993. The effect of establishment methods and fertilization practices on nitrate leaching from turfgrass. J Environ Qual. 22:119 125. Gitelson, A. and M.N. Merzlyak.1994. Spectral reflectance changes associated with autumn senescenceof Aesculutus Hhippocastanum (L.) and Acer Platanoides (L.) leaves: Spectral features and relation to c hlorophyll estimation. J Plant Physiol. 143:286 292. Gonzalez, R. 2010. Phosphorus response and orthophosphate leaching in floratam St. Augustinegrass and empire zoysiagrass. Dissertation presented to the University of Florida Graduate School, Gainesville, FL. Graham, J., and P. H. Dernoeden. 2002. Dollar spot Severity, tissue Nitrogen, and soil microbial activity in bentgrass as influenced by nitrogen source. Crop Sci. 42:480 488. Graham, N. 2009. Inorganic nit rogen leaching and agronomic response of St. Au gusti n e grass to nitrogen fertilization strategies under residential lawn conditions. Thesis presented to the University of Florida Graduate School, Gainesville, FL Gross, C.M. 1990. Runoff and Sediment Losses from Tall Fescue under Simulated Rainfall. J. Environ. Qual. 20:604 607. Guyot, G. 1990.Optical properties of vegetation canopies.P.19 43. In M.D. Steven and J.A. Clark (ed.) Applications of remote sensing in agriculture, London.

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136 Haydu, J.J., A.W. Hodges, and C.H. Hall. 2006. FE632 Economic impacts of turfgrass and lawn care industry in the United States. University of Florida, IFAS, Agricultural E conomics, Coop. Ext. Serv., Gainesville, FL. Havlin, J.L., J.D. Beaton, S.L. Tisdale, and W.L. Nelson. 2005. Soil fe rtility and fertilizers: an introduction to nutrient management. Prentice Hall, NJ. Hochmuth, G., T. Ne il, J.B. Sartain, J.B. Unruh, C. Martinez, L.E. Trenholm, and J. Cisar. 2011. SL 283. Uninte n ded consequences associated with certain urban fertilizer ordinances University of Florida, IF AS, Soil and Water Sci., Coop. Ext. Serv., Gainesville, F L. Hodges, A.W., and T.J. Stevens. 2010. FE632 Economic contributions of turfgrass industry in Florida. University of Florida, IFAS Agricultural Economics, Coop. Ext. Serv., Gainesville, FL. Hornsby H.D., B.G. K atz, J.F. Bohlke, and M.F. Mokray. 1999. Source and chronology of nitrate contamination in spring waters, Suwanee river basin, Florida. USGS. Horst G.L., L.B. Fenn, and N.B. Dunning. 1985. Bermudagrass turf response s to nitrogen sources. Journal of Americ an Society for Horticultural Science 11:759 761. Hummel, N.W., and D.V. Waddington. 1981. Evaluation of slow release nitr ogen sources on Baron Kentucky Bluegrass. Soil Sci. Soc. Am. J. 45:966 970. Killian, K.C., O.J. Attoe, and L.E. Engelbert. 1 966. Urea formaldehyde as a slowly available form of nitrogen for Kentucky b luegrass. Agron. J. 58: 204 206. Kruse J.K., N.E. Christians, and M.H. Chaplin. 2006. Remote sensing of nitrogen stress in creeping Bentgrass. Agron. J. 98:1640 1645. Landschoot, P.J., and D.V. Waddington. 1987. Response of turfgrass to various nitrogen fertilizers. Soil Sci. Soc. Am. J. 51:225 230 Liyanage, C.E., M.I. Thabrew, and D.S.P. Kuruppuarachchi. 2000. Nitrate pollution in ground water of Kalpitiya: an evaluation of the content of nitrates in the water and food items cultivated in the area. J. Nat. Sci. Foundation of Sri Lanka. 28(2): 101 112. Malley, D.F. L. Lockhart, P. Wilkinson, and B. Hauser. 2000. Determination of carbon carbonate, nitrogen, and phosphorus in fresh water sediments by near infrared reflectance spectroscopy: Rapid analysis and check on conventional analytical methods. J. Paleolim. 24:415 425. Mallin, M.A., and T.L. Wheeler. 2000. Nutrient and fecal coliform discharge from coastal North Carolina golf courses. J. Environ. Qual. 29:979 986.

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137 Mangiafico, S.S ., and K. Guillard. 2005. Turfgrass reflectance m easurements, c hlorophyll, and soil nitrate desorbed from anion e xchange m embranes Crop Sci. 45:259 265. Marschner, H. 2002. Mineral nutrition of higher plants. Academic Press, London, UK. McCrimmon, J.N. 2000. Nitrogen and potassium effects on the macronutrient and micronutrient content of zoysiagrasses. J. Plant Nutrition 23(5): 683 696. Morris, K.N and R.C. Shearman. 2011. Turfgrass evaluations guidel ines. N T EP evaluations guidelines. Available at: http://www.ntep.org/pdf/ratings.pdf Petrov ic, A.M. 2004. Nitrogen Source and Timing Impact on Nitrate Leaching from Turf.Acta Hort. 661. Pimentel, D 2000. Soil Erosion and the Threat to Food Security and the Environme nt. Ecosystem Health 6:221 226. Pocklington, T.E., J.D. Butler, and T.K. Hodges. 1974. Color evaluation of p oa pratensis cultivars. J. Sports Turf Res. Inst. 66:134 140 Quiroga, H.M., G.H. Picc hioni, and M.D. Remmenga 2001. Bermudagrass fertilized with slow release nitrogen sources. I. n itrogen uptake and potential leaching losses. Environ. Qual. 30:440 448. Rodriguez, I. R. and G.L. Miller. 2000. Using a chlorophyll meter to determinate the ch lorophyll concentration, nitrogen concentration, and visual quality of St. Augustinegrass. Hort. Science 35:751 754. Saha, S.K. 2004. Effect of fertilizer source on nitrate leaching, plant water consumption, and turf and ornamental quality. Thesis presente d to the University of Florida Graduate School, Gainesville, FL. Sartain, J.B. 2009. Environmental nutrient management manual course. University of Florida, Gainesville, FL. Sartain, J.B. 2001. SL181. Soil and tissue testing and interpretation for f lorida t urfgrasses University of Florida, IFAS, Soil and Water Sci., Coop., Ext. Serv., Gainesville, FL. Sartain, J.B. 1992. Natural organic slow release nitrogen sources for turfgrasses. Proc. Fla. State Hort. Soc. 105:224 226. Sartain, J.B. 2008. Comparative i nfluence of nitrogen sources on nitrogen leaching and St. Augustinegrass quality, growth and nitrogen uptake. Soil Crop Sci. Soc. Florida Proc. 67:43 47.

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138 Sartain, J.B., and J.K. Kruse. CIR1262. 2001. Selected fertilizers used in turfgrass fertilization U niversity of Florida, IFAS, Soil and Water Sci., Coop., Ext. Serv., Gainesville F L. Sartain, J.B., L.T. Trenholm, E.F. Gilman, T.A. Obreza, and G. Toor ENH1115 2008. Frequently asked questions about landscape fertilization for florida friendly landscap ing ordinances. University of Florida. IFAS, Environmental Hort., Coop., Ext. Serv., Gainesville, FL. SAS Institute Inc. 2009. SAS Edition Cary, NC. SAS Institute Inc. Sharma, S. 2009. Effect of nitrogen rates and mowing height s on nitrogen leaching, turf quality and spectral reflectance. Thesis presented to the University of Florida Graduate School, Gainesville, FL. Snyder, G.H. B.J. Augustin, and J.M. Davidson, J.M. 1984. Moisture sensor controlled irrigation for reducing N leaching in bermudagrass turf. Agron J. 76:964 969. Sonmez, N. K., Y. Emekli, M. Sari, and R. Bastug. 20 08. Relationship between spectral refle ctance and wa ter stress conditions of bermudagrass. New Zealand J of Agri. 51:223 263. Spectrum Technologies Inc. 2009. 2950 Field Scout CM 1000 Chlorophyll Meter Manual. Plainfield, Illinois, USA. Trenholm, L.E., R. N. Carrow, and R.R. Duncan. 1999. Relationship of multispectral radiometry to qualitative data in turfgrass research. Crop Sci. 39:763 769. Trenholm, L.E., and J.B. Unruh. 2004. Warm season turfgrass responses to fertilizer rat es and sources. J of Plant N ut rition 28:991 999. Trenholm, L.E., and J.B. Unruh. 2005. The florida lawn handbook. University Press of Florida, FL. Trenholm, L.E. and J.B. Unruh, J.B. 2007. Saint Au gustinegrass fertilizer trials. J. Plant Nutrition. 30:453 461. T renholm, L.E. 2008. ENH1089 Urban turf f ertilizer rule for home lawn fertilization. University of Florida. IFAS, Environmental Hort., Coop., Ext. Serv., Gainesville, FL. Trenholm, L.E., R.N. Carrow, and R.R. Duncan. 1999. Relationship of multispectral radiometry to qualitat ive data in turfgrass research. Crop Sci. 39:763 769. Troech, F.R 1991. Soil and Water Conservation 2 nd ed Englewwod Cliffs, NJ: Prentice Hall. Turgeon, A. 2005. Turfgrass management. 7 th ed. Pretince Hall, Englewood Cloffs, NJ.

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139 Unruh, J.B., L.E. Trenho lm, and K.E. Kenworthy 2007. Zoysiagrass for Florida lawns: a passing fancy or here to stay?. Florida turf digest. Watschake, T.L. 1990. The environmental benefits of turfgrass and their impact on the green

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140 BIOGRAPHICAL SKETCH Ronald J. Castillo Chaves is the son of Ronald Castillo Sandi and Jackeline Chaves Murillo and was born in Heredia, Costa Rica. Ronald grew up in a family agricultural operation business which cultivated his passion for crops and especially turfgrass. Ronald has work ed on his family farms since he was 14, helping in all daily activities Later, he attended E ARTH University in Costa Rica due to his interest in environmental sustainable agriculture and he received a BS in Agronomy and Conservation of Natural Resources in De cember 2007. During his studies at EARTH he went on an internship at Iowa State University, in the Environmental Horticulture Department which inspired his interest in turfgrass research. Ronald joined the Environmental Horticulture Department at the Unive rsity of Florida in Gainesville and began his master program in turfgrass nutrition under the supervision of Dr. Laurie Trenholm in May 2008. He received his Master of Science degree from the University of Florida in the fall of 2011. After his studies, Ro nald will return to Costa Rica to work in the turfgrass and agricultural industry.