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Evaluating Nutrient Management Systems for Organically-Produced Greenhouse Colored Bell Pepper (Capsicum Annuum L.)

Permanent Link: http://ufdc.ufl.edu/UFE0044815/00001

Material Information

Title: Evaluating Nutrient Management Systems for Organically-Produced Greenhouse Colored Bell Pepper (Capsicum Annuum L.)
Physical Description: 1 online resource (157 p.)
Language: english
Creator: Beyer, Allison L
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: bell -- greenhouse -- organic -- pepper
Horticultural Science -- 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: A potentially lucrative market opportunity for growers is presented by high price premiums associated with greenhouse, organic, red bell pepper. The objective of this project was to identify the organic greenhouse nutrient management system that produces the greatest yield, quality and economic returns from determinate red bell pepper plants (Capsicum annuum L.). Treatments that varied in compost amendments to container growing media (three levels) and fertilizer source (five levels) were arranged in a randomized complete block design replicated four times at the University of Florida’s greenhouses near Citra, Florida in Fall of 2010 and Spring of 2011. The three compost amendment treatments in a 1 peat : 1 pine bark container media were: 1) no compost; 2) 30% yard waste compost; or 3) 30% poultry litter compost (by volume). The four organic fertilizer treatments included: 1) dry granular sources only; 2) a nutrient solution delivered through the irrigation system only; 3) granular sources applied at transplanting and nutrient solution beginning at sidedress; and 4) nutrient solution beginning at transplanting and granular sources applied at sidedress. The organic systems were compared to the fifth fertilizer treatment that represented conventional hydroponic systems of mineral-based nutrient solution applied regularly through the irrigation system. Throughout the experiment, data were collected on plant height, relative leaf nitrogen status, and the pH, electrical conductivity and nitrate concentration of media leachate. At harvest, data were collected on whole plant dry weight, leaf percent total kjeldahl nitrogen, and fruit yield, quality and nitrogen use efficiency. The media amended with poultry litter compost combined with the organic fertilizer treatments that derived at least half of total season nutrients from granular sources produced the highest organic marketable yields of 57-138% of the conventional hydroponic control. A sensitivity analysis was conducted based on the yields and input costs in this study. Compared to greenhouse-grown red bell pepper produced conventionally, producing organically resulted in a 30% average increase in estimated partial net returns due to a 35% reduction in nutrient management input costs and an average increase in market price of 75%, even with an average reduction in yield of 30%.
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 Allison L Beyer.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Treadwell, Danielle.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044815:00001

Permanent Link: http://ufdc.ufl.edu/UFE0044815/00001

Material Information

Title: Evaluating Nutrient Management Systems for Organically-Produced Greenhouse Colored Bell Pepper (Capsicum Annuum L.)
Physical Description: 1 online resource (157 p.)
Language: english
Creator: Beyer, Allison L
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2012

Subjects

Subjects / Keywords: bell -- greenhouse -- organic -- pepper
Horticultural Science -- 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: A potentially lucrative market opportunity for growers is presented by high price premiums associated with greenhouse, organic, red bell pepper. The objective of this project was to identify the organic greenhouse nutrient management system that produces the greatest yield, quality and economic returns from determinate red bell pepper plants (Capsicum annuum L.). Treatments that varied in compost amendments to container growing media (three levels) and fertilizer source (five levels) were arranged in a randomized complete block design replicated four times at the University of Florida’s greenhouses near Citra, Florida in Fall of 2010 and Spring of 2011. The three compost amendment treatments in a 1 peat : 1 pine bark container media were: 1) no compost; 2) 30% yard waste compost; or 3) 30% poultry litter compost (by volume). The four organic fertilizer treatments included: 1) dry granular sources only; 2) a nutrient solution delivered through the irrigation system only; 3) granular sources applied at transplanting and nutrient solution beginning at sidedress; and 4) nutrient solution beginning at transplanting and granular sources applied at sidedress. The organic systems were compared to the fifth fertilizer treatment that represented conventional hydroponic systems of mineral-based nutrient solution applied regularly through the irrigation system. Throughout the experiment, data were collected on plant height, relative leaf nitrogen status, and the pH, electrical conductivity and nitrate concentration of media leachate. At harvest, data were collected on whole plant dry weight, leaf percent total kjeldahl nitrogen, and fruit yield, quality and nitrogen use efficiency. The media amended with poultry litter compost combined with the organic fertilizer treatments that derived at least half of total season nutrients from granular sources produced the highest organic marketable yields of 57-138% of the conventional hydroponic control. A sensitivity analysis was conducted based on the yields and input costs in this study. Compared to greenhouse-grown red bell pepper produced conventionally, producing organically resulted in a 30% average increase in estimated partial net returns due to a 35% reduction in nutrient management input costs and an average increase in market price of 75%, even with an average reduction in yield of 30%.
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 Allison L Beyer.
Thesis: Thesis (M.S.)--University of Florida, 2012.
Local: Adviser: Treadwell, Danielle.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2012
System ID: UFE0044815:00001


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1 EVALUATING NUTRIENT MANAGEMENT SYSTEMS FOR ORGANICALLY PRODUCED GREENHOUSE COLORED BELL PEPPER ( CAPSICUM ANNUUM L.) By ALLISON LEIGH BEYER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DE GREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2012

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2 2012 Allison Leigh Beyer

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3 To my father, mother, sister, husband and all others who unconditionally supported me

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4 ACKNOWLEDGMENTS I would first and foremost like to thank my husband, Joey Cassata Jr., for his undying love and support during my masters education and all the years leading up to it and for the many times he spent his day s off from work to assist me in the field. I could not imagine experiencing it all without my soul mate by my side. Similarly, I am forever indebted to my parents and sister for everything they have done and continue to do for me to help me achieve my goals I would like to express my sincere gratitude to my advisor, Dr. Danielle Treadwell, for her unparalleled kindness and encouragement and for being a wonderful source of inspiration for me, professionally educationally and personally, throughout the last two years. I would like to thank my committee member, Dr. Dan iel Cantliffe for supporting me before, during and after my masters education, and imparting invaluable knowledge and wisdom to me in the process that have made me a better student and scientist. I would also like to thank my committee member Dr Michael Gunderson, and also Dr. Alan Hodges for inciting my interest in the economic side of horticulture and assisting me in the economic analysis of my project. I thank Dr. Peter Stoffella, Dr. Salvador Gezan Dr. Lance Osborne and James Colee for their assistan ce with the statistical aspects of my research. I must thank biologist, Michael Alligood, a billion and one times for his incredible expertise in building the ingenious fertigation and irrigation system, without which my research could not have been done, not to mention his willingness to spend many tedious hours with me collecting harvest data. I would also like to thank Dr. Rebecca Dar nell, Libby Rens, Wenjing Guan, Bee Ling Poh Angelos Deltsidis Maggie Goldman, Brandon Cassata and the entire Citra crew for their assistance with my research.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 8 LIST OF FIGURES ................................ ................................ ................................ ........ 10 ABSTRACT ................................ ................................ ................................ ................... 12 CHAPTER 1 LITERATURE REVIEW ................................ ................................ .......................... 14 Bell Pepper Production in the U.S. and World ................................ ........................ 14 Greenhouse Production ................................ ................................ .......................... 16 Organic Production ................................ ................................ ................................ 19 Greenhouse Organic Production ................................ ................................ ............ 22 Organic Media ................................ ................................ ................................ .. 23 Organic Fertilizer and Application Strateg ies ................................ .................... 26 Other Organic Amendments ................................ ................................ ............. 29 Fertigation System Strategies ................................ ................................ .......... 30 Previous Organic Greenhouse Production (Commercial and Research) ......... 31 Organic Greenhouse Production of Red Bell Pepper Economic Analysis .............. 34 Objectives and Hypothesis ................................ ................................ ..................... 36 2 EVALUATION OF GROWING MEDIA, FERTILIZER SOURCE AND NUTRIENT APPLICATION STRATEGIES FOR AN EFFECTIVE ORGANIC GREENHOUSE BELL PEPPER NUTRIENT MANAGEM ENT SYSTEM ................................ .......... 38 Materials and Methods ................................ ................................ ............................ 38 Site Description ................................ ................................ ................................ 38 Exper imental Design ................................ ................................ ........................ 38 Overview ................................ ................................ ................................ .... 38 Fertilizer treatments ................................ ................................ ................... 40 Compost t reatments ................................ ................................ ................... 42 Irrigation system ................................ ................................ ......................... 43 Crop Seasonal Management ................................ ................................ ............ 44 Tr ansplant production ................................ ................................ ................ 44 Temperature control and trellising ................................ .............................. 44 Integrated pest management practices ................................ ...................... 45 Data Collection ................................ ................................ ................................ 46 Measurements during the growing season ................................ ................ 46 Leachate sampling and analysis ................................ ................................ 47 Tissue sampling and analysis ................................ ................................ .... 47 Harvest ................................ ................................ ................................ ...... 48

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6 Statistical Analy sis ................................ ................................ ............................ 49 Results and Discussion ................................ ................................ ........................... 50 Cultivar Selection ................................ ................................ ............................. 50 Air and C ompost Treatment Temperature and Chemical/Physical Properties .. 51 Bell Pepper Yield and Size Distribution (kg/m 2 ) ................................ ................ 54 Fall 2010 ................................ ................................ ................................ .... 55 Spring 2011 ................................ ................................ ................................ 57 Bell Pepper Quality (kg/m 2 ) ................................ ................................ .............. 59 Fall 2010 ................................ ................................ ................................ .... 59 Spring 2011 ................................ ................................ ................................ 59 Bell Pepper Fruit Counts and Percent Yields ................................ ................... 60 Fall 2 010 ................................ ................................ ................................ .... 60 Spring 2011 ................................ ................................ ................................ 62 Plant Height and Leaf SPAD values ................................ ................................ 64 Fall 2010 ................................ ................................ ................................ .... 64 Spring 2011 ................................ ................................ ................................ 65 Leachate pH, EC and Nitrate Concentration ................................ .................... 66 Fall 2010 ................................ ................................ ................................ .... 67 Spring 2011 ................................ ................................ ................................ 71 Plant Biomass and Nutrient Content at Harvest ................................ ............... 73 Fall 2010 ................................ ................................ ................................ .... 73 Spring 2011 ................................ ................................ ................................ 75 Fruit Characteristics and Nutrient Content/Efficiency at Harvest ...................... 75 Fall 2010 ................................ ................................ ................................ .... 75 Spring 2011 ................................ ................................ ................................ 77 Conclusions ................................ ................................ ................................ ............ 78 3 ECONOMIC ANALYSIS ................................ ................................ ........................ 118 Materials and Methods ................................ ................................ .......................... 118 Site Description ................................ ................................ .............................. 118 Experimental Design ................................ ................................ ...................... 118 Overview ................................ ................................ ................................ .. 118 Fertilizer treatments ................................ ................................ ................. 119 Compost treatments ................................ ................................ ................. 122 Irrigation system ................................ ................................ ....................... 122 Crop Seasonal Management ................................ ................................ .......... 123 Temperature control and trellising ................................ ............................ 123 Integrated pest management practices ................................ .................... 124 Frui t Yields ................................ ................................ ................................ ..... 125 Harvest ................................ ................................ ................................ .... 125 Statistical analysis ................................ ................................ .................... 125 Economic Analy sis ................................ ................................ ......................... 126 Results and Discussion ................................ ................................ ......................... 128 Nutrient Management Cost Analysis ................................ .............................. 128 Sensitivity Analysis ................................ ................................ ......................... 131 Conclusions ................................ ................................ ................................ .......... 138

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7 4 CONCLUSIONS AND SUMMARY ................................ ................................ ........ 147 LIST OF REFERENCES ................................ ................................ ............................. 151 BIOGRAPHICAL SKETCH ................................ ................................ .......................... 157

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8 LIST OF TABLES Table page 2 1 the determinate red bell pepper study in the greenhouse at in Fall 2010 and Spring 2011 ... 83 2 2 delivered through the irrigation system to greenhouse grown determinate red bell pepper plants in Fall 2010 and Spring 2011 ................................ ................. 84 2 3 Explanation of organic fertilizer treatments applied to greenhouse grown determinate red bell pepper plants in Fall 2010 and Spring 2011 ....................... 84 2 4 Relevant physical and chemical properties of media components in the greenhouse grown determinate red bell pepper study in Fall 2010 and Spring 2011 ................................ ................................ ................................ ................... 86 2 5 Relevant physical an d chemical properties of custom media mixes that represent the compost treatments in the greenhouse grown determinate red bell pepper study in Fall 2010 and Spring 2011 ................................ ................. 86 2 6 The effects of c onventional and organic fertilizer and compost treatments on total yields, marke table yields and fruit size distribution (kg/m 2 ) from greenhouse grown determinate red bell pepper plants in Fall 2010 ................... 89 2 7 The effects of conventional and organic fertilizer and compost treatments on total yields, marke table yields and fruit size distribution (kg/m 2 ) from greenhouse grown determinate red bell pepper plants in Spring 2011 .............. 93 2 8 The effects of conventional and organic fertilizer and compost treatments on yield of culled fruit (kg/m 2 ) from greenhouse grown determinate red bell pepper plants in Fall 2010 ................................ ................................ .................. 95 2 9 The effects of conventional and organic fertilizer and compost treatments on yield of culled fruit (kg/m 2 ) from greenhouse grown determinate red bell pepper plants in Spring 2011 ................................ ................................ .............. 96 2 10 The effects of conventional and organic fertilizer and compost treatments on total yield (# of fruit per m 2 ) and marke table yield, total culls and blossom end rot ( # of fruit per m 2 and percent of total yield by weight ) in Fall 2010 ................ 99 2 11 The effects of conventional and organic fertilizer and compost treatments on total yield (# of fruit per m 2 ) and marke table yield, tot al culls and blossom end rot ( # of fruit per m 2 and percent of total yield by weight ) in Spring 2011 ......... 102

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9 2 12 The effects of conventional and organic fertilizer and compost treatments on plant height and leaf SPAD values of greenhou se grown determinate red bell pepper plants in Fall 2010 ................................ ................................ ................ 105 2 13 The effects of conventional and organic fertilizer and compost treatments on plant height and leaf SPAD values of greenhouse g rown determinate red bell pepper plants in Spring 2011 ................................ ................................ ............ 107 2 14 The effects of conventional and organic fertilizer and compost treatments on the pH, electrical conductivity (EC) and nitrate (N O 3 N) concentration of leachate from greenhouse grown determinate bell pepper plants in Fall 2010 110 2 15 The effects of conventional and organic fertilizer and compost treatments on the pH, electrical conductivity and nitrate (NO 3 N) concentration of leachate from greenhouse grown determinate bell pepper plants in Spring 2011 .......... 111 2 16 The effects of conventional and organic ferti lizer and compost treatments at harvest on whole plant dry weight, leaf percent total kjeldahl n itrogen (TKN), fruit percent TKN and fruit nitrogen use efficiency (NUE) in Fall 2010 .............. 113 2 17 T he effects of conventional and organic fert ilizer and compost treatments at harvest on whole plant dry weight, leaf percent t otal kjeldahl n itrogen (TKN), fruit percent TKN and fruit nitrogen use efficiency (NUE) in Spring 2011 ......... 116 3 1 Sources and prices for nutrient management materials used in greenhouse production of conventional and organic red bell peppers from determinate plants in Fall 2010 and Spring 2011 ................................ ................................ 140 3 2 Nutrient management costs in greenhouse production of determinate red bell pepper plants under two conventional and two organic fertilizer and media treatments in Fall 2010 and Spring 2011 ................................ .......................... 141 3 3 Estimated partial net return for yields of determinate red bell pepper plants grown in a greenhouse with conventional fertilizer and two different compost treatme nts in Fall 2010 ................................ ................................ ..................... 143 3 4 Estimated partial net return for yields of determinate red bell pepper plants grown in a greenhouse with two different organic fertilizer treatmen ts and one compost treatment in Fall 2010 ................................ ................................ ........ 144 3 5 Estimated partial net return for yields of determinate red bell pepper plants grown in a greenhouse with conventional fertilizer and two different compost treatments in Spring 2011 ................................ ................................ ................ 145 3 6 Estimated partial net return for yields of determinate red bell pepper plants grown in a greenhouse with two different organic fertilizer treatments and one compost treatment in Spring 2011 ................................ ................................ .... 146

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10 LIST OF FIGURES Figure page 2 1 The experiment site: a multi bay, passively ventilated, saw tooth style (UF) Plant Scien ce Research and Education Unit ( PSREU ) in Mari on County near Citra, Florida .... 81 2 2 The experim ent site: inside the greenhouse ................................ ....................... 81 2 3 Experiment set up ................................ ................................ .............................. 82 2 4 Irrigation design and equipment for delivery of water and nutrients to 2010 and Spring 2011 ................................ ................................ ........................ 85 2 5 Details of individual micro irrigation units. ................................ .......................... 85 2 6 Inside the greenhouse, air temperature at a height of 1 meter a nd the temperature of each of the three media/compost mixes in Fall 2010 ................. 87 2 7 Total yield (kg/m 2 ) i nteraction effects in Fall 2010 ................................ .............. 90 2 8 Yield (kg/m 2 83.9 mm in fruit diameter) int eraction effects in Fall 2010 ................................ ................................ ............................. 91 2 9 Yield (kg/m 2 74.9 mm in fruit diameter) int eraction ef fects in Fall 2010 ................................ ................................ ............................. 92 2 10 Yield (kg/m 2 64.9 mm in fruit diam e ter) inter action effects in Spring 2011 ................................ ................................ ......................... 94 2 11 Yield (kg/m 2 sum of blossom end rot, sunscald, radial cracking, flat shape, misshapen and russeting ) interaction effects in Spring 2011 ................................ ................................ ................................ ................... 97 2 12 Yield of blossom end rot (kg/m 2 ) interacti on effects in Spring 2011 .................... 98 2 13 Total yield (# of fruit/m 2 ) i nteraction effects in Fall 2010 ................................ ... 101 2 14 Market able yield (# of fruit/m 2 ) int eraction effects in Fall 2010 ......................... 101 2 15 Total yield (# of fruit/m 2 ) interact ion effects in Spring 2011 ............................... 103 2 16 Yield of blossom end rot (# of fruit/m 2 ) interac tion effects in Spring 2011 ........ 104 2 17 Percent blossom end rot inter action effects in Spring 2011 .............................. 104

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11 2 18 Plant height (cm) at 40 days after transplant (DAT) intera ction effects in Fall 2010 ................................ ................................ ................................ ................. 106 2 19 Plant height (cm) at 44 DAT inter action effects in Spring 20 11 ........................ 109 2 20 Leaf SPAD values at 21 DAT interact ion effects in Spring 2011 ...................... 109 2 21 Electrical conductivity (EC) of leachate (mS/ cm) at 30 DAT interaction effec ts in Spring 2011 ................................ ................................ ................................ .. 112 2 22 Whole plant dry weight (g) at harvest intera ction effects in Fall 2010 ............... 115 2 23 Fruit percent total kjeldahl nitrogen ( TKN ) at harvest interaction effects in Fall 201 0 ................................ ................................ ................................ ................. 115 2 24 Fruit lobe number at harvest interac tion effects in Spring 2011 ........................ 117

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12 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the R equirements for the Degree of Master of Science EVALUATING NUTRIENT MANAGEMENT SYSTEMS FOR ORGANICALLY PRODUCE D GREENHOUSE COLORED BELL PEPPER ( CAPSICUM ANNUUM L.) By Allison Leigh Beyer August 2012 Chair: Danielle D. Treadwell Major: Horticultural Science A potentially lucrative market opportunity for growers is presented by high price prem iums associated with green house, organic, red bell pepper The objective of this project was to identif y the organic greenhouse nutrient management sy s tem t hat produces the greatest yield, quality and economic returns from determinate red bell pepper plants ( Capsicum annuum L .) T reatments that varied in compost amendments to container growing media (three levels) and fertilizer source (five levels) were arranged in a randomized complete block design replicated four times at the University of greenhouses near Citra, Florida in Fall of 2010 a nd Spring of 2011. The three compost amendment treatments in a 1 peat : 1 pine bark container media were : 1) no compost; 2) 30% yard waste compost; or 3) 30% poultry litter compost (by volume). The f our orga nic fertilizer treatment s included: 1) dry granular sources only; 2) a nutrient solution delivered thr ough the irrigation system only; 3) granular sources applied at trans planting and nutrient solution beginning at sidedress; and 4) nutrient solution beginning at trans planting an d granula r sources applied at sidedress. The organic systems were compared to the fifth fertilizer treatment that represented conve n tional hydroponic system s of mineral based nutrient solution applied regularly through the

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13 irrigation system. Throughout the experiment data were collect e d on plant height, relative leaf ni trogen status and the pH, electrical conducti vity and nitrate concentration of media leacha te. At harvest, data were collect e d on whole plant dry weight, leaf percent total kjeldahl n itroge n, and fruit yield quality and nitrogen use efficiency The m edia amended with poultry litter compost combined with the organic fertilizer treatments that derived at least half of total season nutrients from granular sources produced the highest organic m arketable yiel ds of 57 138 % of the conventional hydroponic control. A sensitivity analysis was conducted based on the yields and i nput costs in this study Compared to greenhouse grown red bell pepper produced conventionally, producing organically resulted in a 30% average increase in estimated partial net returns due to a 35% reduction in nutrient management input costs and an average increase in market price of 75%, even with an average reduction in yield of 30%.

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14 CHAPTER 1 LITERATURE REVIEW Bell Pepper Production in the U.S. and World Bell peppers ( Capsicum annuum L.) are a member of the S olanacea e family and originated from Mexico and Central America with evidence of its use by early inhabitants as many as 12,000 years ago. A phenolic compound called ca psaicin is responsible for the pungency in peppers and different cultivars differ markedly in their content of the chemical, resulting in many different kinds of pepper, including sweet bell, cherry, jalapeno, habaneros, cayenne and Scotch Bonnet. In 2007, over 26 million metric tons of pepper s were produced globally (U.S. Dept. of Agriculture, 2008a). China the United States (U.S.) ranked sixth with about 855,000 metric to ns produced ( U.S. Dept. of Agriculture 2008 a ) However the majority of pepper produced in the U.S. is the sweet bell pepper, accounting for nearly 78% of all peppers produced in the U.S. in 2007 ( 665,000 met ric tons on 25,237 hectares ) ( U.S. Dept. of Agriculture 2008b ) Within the U.S., Florida is the second leading producer of bell peppers behind California, producing 197,000 metric tons for a value of $ 183 million in 2007, accounting for 30% of total U.S. be ll pepper production volume and 39% of total U.S. bell pepper production value ( U.S. Dept. of Agriculture 2008b ) In 2008, bell pepper production i n Florida accounted for 7,822 hectares of cropland and $267 million in value ( U.S. Dept. of Agriculture 2009 a ). B ell pepper plants are managed as annuals in temp erate cl imates. Peppers are particularly sensitive to low temperatures and are relatively slow to establish comp ared to other solanaceous crops Peppers are traditionally grown in the field, and in the Southeast, they are typically grown on plastic mulched beds an d irrigated through sub

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15 surface or drip irrigation systems (Olson and Santos, 2013) Field grown peppers are typically determinate cultivars where the plant s g row to a certain size, produce fruit and senesce with a season length of about 5 6 months from seeding and one to three harvests of mature green peppers for a period of approximately one month G reenhouse production has increased over the past couple of decades, and bell pepper has become a popular crop in protected systems along with tomato, cucumb er, strawberry, lettuce, herbs, ornamentals and transplants ( Greer and Diver, 2000; Jovicich et al., 2005) Compared to the field, b ell peppers grown in the greenhouse are typically indeterminate cultivars, where the plants continually develop and grow fro m new meristems that produce new stems, le aves, flowers and fruit. Season length is 10 11 months from seeding and weekly harvests of colored pepper co ntinue for a period of up to 6 7 months All peppers start out green and gradually mature to typically a r ed, orange or yellow color. Consumer demand for colored bell pepper s has increased their market pri ce by almost two times that of green pepper ( Cantliffe et al., 2008; Jovicich et al., 2005) U.S. production of fresh bell pepper has been continually on the rise, tripling in the span of time between 1978 and 2003 from approximately 227,000 to 680,000 metric tons per year (Kelley and Boyhan 200 9 ) During this same time frame, there has been a 3.5 fold increase (from 272,000 to 953,000 metric tons ) and 2.5 fo ld increase (from 1.3 to 3.2 kg per year per person) in domestic consumption and per capita use, respectively (Kelley and Boyhan, 2009) Despite the considerable rise in domestic production, the U.S. imports a substantial amount of its pepper s to supplemen t the ever increasing domestic demand. U.S. import of peppers exceeds its export of peppers, with

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16 the import export gap steadily widening over time (Kelley and Boyhan, 2009) In 2007, imported peppers accounted for 40% of the peppers on the domestic market (Kelley and Boyhan, 2009) The majority of these imports come from Mexico, Canada, the Netherlands, Dominican Republic, Israel and Spain. Part of the reason why some of these countries are dominating the retail industry of pepper is because they are provi ding high quality greenhouse grown colored fresh pepper during those seasons when field production is reduced or non existent due to non optimal natural weather conditions ( Cantliffe et al., 2008; Jovicich et al., 2005) Because states in southeast ern U.S. have such mild climate, there is a large economically viable opportunity for southeast growers to fulfill this winter market for greenhouse grown peppers, thereby reducing the need for imports from abroad. Greenhouse Production Greenhouses are permanent structures that have metal or wood structural supports roof and sides made of glass, plastic and/or mesh netting and a structural design that allows for either active or passive ventilation. They are built to create a protective shell around a crop in whi ch : E nvironmental extremes can be avoided leading to growing season extension and uninterrupted labor ; T he surrounding growing environment can be optimized an d synchronized with the demands and requirements of the particular crop by modifying fine tuning and automating environmental factors such as temperature and light levels based on sensors b uilt into the greenhouse system ; Y ield per unit area of land and produce quality can be increased by creating a protected, intensive, high density and high efficien cy crop growing environment which is advantageous as our rising population and urbanization limits suitable agricul tural land ;

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17 I nputs such as water, fertilizer and pest control products can be precisely applied, controlled, contained, recycled and adjuste d according to plant demands resulting in reduction of waste and conservation of resources and money ; and T here is an opportunity an d flexi bility to produce specialty crops, on a small or large scale, during non peak production times using a variety of different systems and materials and thus earn premium prices in the absence of market competition There are many advantages associated with greenh ouse production that contribute to its increase in popularity as a production system, particularly for relati vely challenging and nutrient demand ing crops like bell pepper. The result is a value added product for which there is high demand. For example, greenhouse grown colored bell peppers are typically priced 3 to 5 times greater than field grown (Jovicich et a l., 2005) Colored bell peppers are more difficult to grow because they have to remain on the plant longer (two to three weeks) to ripen for color development, making them more susceptible to disease and quality problems, so growing them under the protecti on of a greenhouse increases their yield potential ( Cantliffe et al., 2008 ; Jovicich et al., 2003; Jovicich et al., 2004 ; Jovicich et al., 2005; Jovicich et al., 2007 ; Shaw and Cantliffe, 2002) Furthermore, t he phase out (and, as a result, increasing cost ) of methyl bromide for soil fumigation of field grown crops emphasizes the considerable market opportunity for greenhouse growers in Florida due to the development of Integr ated Management Practices (IPM) soilless media, and other technologies that eradi cate the need for soil fumigation products and reduce the need for pesticides ( Jovicich et al., 2004; Osborne and Barrett, 2005; Saha and Cantliffe, 2009 ; Shaw and Cantliffe, 2002 ) The main disadvantage associated with greenhouse production is high start up and production costs, mostly associated with the infrastructure, technology and heating systems in cold climates ( Greer and Diver, 2000; Jovicich et al., 2005) Therefore, high value crops must be produced in order to keep the operation profitable.

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18 Whi le our neighbors, Canada and Mexico have increased their greenhous e vegetable production area by 39% and 105%, respectively, from 2002 to 2006, the U.S. has increased greenhouse vegetable production area by only 25% in that same time range (Zbeetnoff Agro Environmental Consulting 2006 ) In 2006, greenhouse vegetable production in Canada, Mexico and the U.S. accounted for 1100, 2300 and 450 hectares respectively Furthermore only 5% of U.S. greenhouse vegetable production is devoted to bell pepper and th is number remained constant between 2002 and 2006, while the fraction of bell pepper grown in greenhouses rose by 60% and 67% in Canada and Mexico, respectively (Zbeetnoff Agro Environmental Consulting 2006 ) In 2006, greenhouse bell pepper production in Canada, Mexico and the U.S. accounted for 279, 350, and 20 hectares respectively The increased global expansion of greenhouse area highlights an obvious opportunity for U.S. growers to expand into this market and reduce relian ce on pepper imports While a wide variety of media, fertilization and irrigation systems exist in greenhouse production, a large proportion of conventional greenhouse systems (especially for colored bell peppers) use hydroponics. In this system, mineral based soluble fertilizers are metered out in small quantities at a regular frequency through low volume irrigation systems ( such a drip or micro jet ) to plants growing in soilless media with low cation exchange capacity (CEC) (Jovicich et al., 2004) T he concentration of nutrients in the stock solution and the duration and frequency of fertigation events are adjusted as the crop progresses through its growth stages and according to crop needs throughout the season. Since the goal of each fertigation event is to deliver only what the pl ant can take up nutrient leaching and water waste is minimized and nutrient and

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19 water levels can be quickly and easily adjusted resulti ng in synchronicity of nutrient and water availability with plant demand As a result of the long term health, producti vity and quality of hydroponic crops, greenhouse production has in many cases become synonymous with hydroponics. Organic Production Traditionally, organic production emphasizes long term soil management strategies that rely on natural inputs and cultural practices that enhance the ecological processes, beneficial microorganisms and organic matter content in order to maintain or improve the physical, chemical and biological condition of the soil Organic n utrient management philosophy typically refers to fi eld production and involves cover crops, crop rotation and application of organic compliant inputs In general, c hemical and synthetic inputs (including synthetic fertilizers and pesticides, growth regulators, antibiotics and genetically modified organisms ) are prohibited and allowable inputs are derived from plant, animal or natural deposits as defined by the Organic Foods Production Act of 1990 (Greer and Diver, 2000). Producers rely on private organizations such as the Organic Mat erials Review Institute (OMRI) that service the organic industry by determining what products are compliant with the United States Department of tandards Final Rule (U.S. Dept. of Agriculture, 201 2 b ) These organizations publish generic mat erial and product name lists of approved inputs. Compliant organic farming systems are certified by an agency accredited by the USDA Organic vegetable acreage in the U.S. a veraged a 15% annual increase between 2000 and 2008 and increased a total of 150% in that time span to an area of nearly 65,000 hectares in 2008 (not including beans, gra ins, fruits, potatoes and herbs based

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20 on information from USDA accredited State and private organic certifiers) (U.S. Dept. of Agriculture 2008c) In 2008, Florida r anked 5 th in certified organic vegetable acreage with 1,465 hectares (U.S. Dept. of Agriculture 2008c) From 1997 2008, there was a four fold increase in U.S. retail sales of organic fruit s and vegetable s accounting for $8 billion in 2008 ( Nutrition Busi ness Journal, 2009; U.S. Dept. of Agriculture, 2009b ) and rising to $10.6 billion in 2010 (Organic Trade Association, 2011) Fresh organic produce has been the most popular organic category during this rise in demand for organic products, with the top fres h organic vegetables in cropland being lettuce (12% of all vegetable acreage), tomatoes (7%) and carrots (6%). ( U.S. Dept. of Agriculture, 2009b ). In 2008, certified and exempt organic bell pepper producti on in the U.S. accounted for 352 harvested hectares 5485 metric tons in production, and $8,088,912 in sales ( U.S. Dept. of Agriculture 2009 a ). In 2008, certified and exempt organic bell pepper produc tion in Florida accounted for 37 harvested hectares and $1,081,821 in sales (U.S. Dept. of Agriculture 20 09 a ). The increasing consumer demand for organic foods is due to a variety of reasons. R esearch s tudies have demonstrated higher nutritional quality and enhanced flavors associated with some organic foods (d el Amor, 2007 ; d el Amor et al., 2008; U.S. Dept. of Agriculture, 2009b ) Because organic production prohibits the use of chemical or synthetic inputs consumers recognize organic foods as potentially healthier and safer alternatives to conventionally grown foods not just in terms of human health but also in terms of the environmental and ecological benefits that the organic standards encourage (NOP) federally regulates certified organic farming systems in way that requires them to : 1) use management practices

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21 that main tain or improve the natural resources of the farm, includi ng soil and water quality; 2) use preventative management pra ctices to manage pests ; and 3) undergo a rigorous annual oversight and certification process (U.S. Dept. of Agriculture, 2012b) Due to d ouble digit growth in consumer demand, the increase in organic acreage still cannot keep up with this demand ( U.S. Dept. of Agriculture, 2009b ) Organic vegeta ble acreage only represents 9% of total vegetable cropland in the U.S ( U.S. Dept. of Agriculture, 2009b ) The low supply and high demand coupled with the fact that organic produce can be priced more than double that of conventional produce ( U.S. Dept. of Agriculture, 2012a ) highlights organic production as a potentially lucrative market for growers to expand into. Furthermore, as research exposes the n egative environmental impacts associated with traditional commercial agriculture, governmental agencies such as the Environmental Protection Agency (EPA) Department of Agriculture and Consumer Services ( DACS) and Water Management Districts (WMD) are focusing on legislative actions to ameliorate these negative impacts A s a result they are creating laws to phase out some products that have traditionally been heavily relied upon (e.g. Chloropicrin, methyl bromide, etc.) and to enforce Best Management Practices (BMPs) that focus on reducing fertilizer and water waste and minimizing contamination of surrounding natural water bodies b y fertilizer and pesticides Therefore, transitioning into the organic produ ction market may be a way for growers to comply with these legal trends and expand into an environmentally and economically sustainable market niche. The major downfall s of organic production are that it can be expensive to become certified, rules and regu lations are strict and inflexible, and products approved for organic use can be expensive and vary widely in their efficiency.

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22 Furthermore, the 2002 USDA National Organic Standards regulation in most cases requires an agricultural area (whether it be open field or greenhouse) to produce organically according to a certifier approved plan for 3 years before its products can be labeled as organic ( U.S. Dept. of Agriculture, 2009b ). Greenhouse Organic Production T heoretically combining organic and greenhouse p roduction together could prove more profitable and environmentally sustainable than either system on its own This could be a potentially viable, scale neutral opportunity for growers throughout the U.S. However the ability to produce year round due to the mild climate and opportunity for crop diversification may give southeastern region growers a competitive edge in the agricultural market and provide supplemental income when fields are out of production. It can be difficult to control diseases weeds and other pests in field organic production because chemical pesticides are prohibited a nd allowed products are relatively expensive and less effective. Bringing organic production i nto the greenhouse will likely facilitate pest control because the greenhouse offers : 1) protection from the unfavorable weather conditions that lead to diseases; 2) use of soilless media that can minimize the threat of soil borne pathogens and weeds; and 3) use of biological control of pests which can introduce and maintain benefic ial insect populatio ns within the structure All thi s could potentially translate to better yields and quality of organic produce. However, successful nutrient management remains an important and challenging issue for organic greenhouse production H istori cally, the nutrient management philosophies associated with greenhous e and organic production are different and attempting to combine them can be quite challenging. The three most important factors to consider in order to create a successful and economical ly practic al organic greenhouse nutrient management

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23 system for fresh market production include me dia, fertilizer source and application strategy Organic Media Plants cannot up take organic forms of nutrients. Fo r example, bacteria and fungi around the roo t system must first mineralize organic nitrogen into ammonium which can then be taken up by the plant or, with the addition of oxygen, can be nitrified by bacteria into nitrate, which is more easily taken up by plants (Evanylo and McGuinn, 2009 ; Sanchez an d Richard, 2009 ; Treadwell et al., 2007 ) Therefore, m ineralizing and nitrifying microorganisms are essential for the transformation of organic forms of nutrients i nto plant available forms. M edia must be optimal not just for the plant health, but also for sustaining microbial activity and grow th throughout the season ( Evanylo and McGuinn, 2009; Succop and Newman 2004 ; Treadwell et al., 2007 ) Although soil based media may be used the advantage s to using soilless media for organic greenh ouse production ar e: 1) it minimizes the risk of soil borne pathogens nematodes and weeds for which there are few effective non chemical control methods approved for organic production ; 2) it avoids any environmental pollutants or residual fertilizers that are p rohibited i n organic production; and 3) it allows growers to custom make media with properties that may be more optimal than local soil type (Greer and Diver, 2000 ; Kuepper and Everett, 2004 ) Media properties that must be consi dered include percent moisture (water h olding capacity), percent oxygen (aeration and drainage capacity), nutrient holding capacity (cation exchange capacity), chemical properties (pH, soluble salt leve ls and electrical conductivity), temperature buffering capacity, organic matter co ntent, carb on to nitrogen ratio (C:N), and bulk density ( Evanylo and McGuinn, 2009; Kuepper and Everett, 2004; Succop and Newman 2004 ; Treadwell et al., 2007 ) All of

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24 these factors interact with each other and with the media microorganism populations to determine th e highly variable and unpredictable rates of mineralization and nitrification I n general, these rates will be slower at lower media temperatures, in dry or waterlogged media conditions and if organic nutrient sources are incorporated too deep into the med ia where oxygen levels are lower (Sanchez and Richard, 2009). Organic greenhouse crops grown in soil are typically grown in bare ground greenhouses and lower cost, less permanent protected agriculture structures. Organic greenhouse crops grown in soilless media are grown in above ground containers such as pots, lay flat bags or troughs in, typically, more modern greenhouse systems. The most common soilless media ingredients used in gre enhouse production include peat pine bark, coconut coir, perlite and ver miculite. Combinations of these media ingredients are often mixed together in different proportions to create a mix with properties that are optimal for the specific crop. For example, peat moss has high water holding capacity and low pH which, as the sole media source may not provide enough oxygen filled pore space to sustain the transformi ng aerobic bacteria and may render certain nutrients unavailable for plant uptake due to the low pH (Sanchez and Richard, 2009 ; Treadwell et al., 2007 ) Therefore, pine bark or perlite is often added to increase air space and improve drainage, and limestone is added to increase the pH to more acceptable levels for nutrient availab ili ty ( Kuepper and Everett, 2004; Succop and Newman 2004) Many companies manufacture soill ess mixes with synthetic wetting agents and starter charges which are prohibited in organic production, therefore it is important to choose media products that do not contain these additives and are

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25 approved for use in organic production (Greer and Diver, 2000 ; Kuepper and Everett, 2004 ; Sanchez and Richard, 2009 ; Treadwell et al., 2007 ) Organic compost can be added to a soilless mix in organic greenhouse systems to: 1) provide and help sustain popul ations of mineralizing/nitrifying microorganisms ; 2) prov ide micronutrients; 3) enhance the temperature buffering capacity of the media ; and 4) cut down on media costs since it tends to be less expensive than other soilless media such as peat moss ( Kuepper and Everett, 2004; Lee et al., 2004; Marinari et al., 20 00 ; Sanchez and Richard, 2009 ; Treadwell et al., 2007 ) Composts can also improve porosity and water holding capacity of the media mix and contribute to the suppress ion of diseases, all of which can affect nutrient management (Celik et al., 2004; Kuepper a nd Everett, 2004; Marinari et al., 2000 ; Sanchez and Richard, 2009; Zinati, 2005 ) The most common composts are derived from either plant sources (e.g. yard waste, spent mushroom substrate) or animal sources (e.g. poultry litter, dairy manure, vermicompost ). Properties vary among different compost sources and will affect the suitability of the media for optimal nutrient uptake and plant growth (Treadwell et al., 2007) For example, compost wi th a high carbon to nitrogen (C: N) ratio (>30) will typically tie up (immobilize) nitrogen in a media mix, making it unavailable for plant uptake, while those with a low C:N ratio (<20) will mineralize organic nitrogen into plant available form at a faster rate (Evanylo and McGuinn, 2009; Paul and Clark, 1996 ; Sanchez an d Richard, 2009 ; Zhai et al., 2009; ) Also, animal based composts tend to have higher pH than plant based composts, and so they will have different effects on the micro organisms and nutrient availability. Due to th e high porosity of most compost the solu ble salt le vels are often high and they can create nutrient imbalances (Kuepper

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26 and Everett, 2004) Compost is not recommended for use alone as a media. Previous research report favorable results with media mixes containing anywhere between 20 50% compost ( Chang et al., 2007; Kraus and Warren, 2000; Kuepper and E verett, 2004; Succop and Newman, 2004; Treadwell et al., 2007; Zhai et al., 2009 ) Organic Fertilizer and Application Strategies Composts are considered an organic nutrient source because many will provide adequate amounts of micronutrients and (depending on source) have variable amounts of phosphorus, potassium, magnesium and calcium (Kuepper and Everett, 2004 ; Sanchez and Richard, 2009 ) However, typically, total nitrogen content is too low (0.5 2. 5%) and becomes available too slowly (10 50% per year) to be able to sustain plant growth on its own without the addition of other organic nutrient sources ( Sanchez and Richard, 2009; Zhai et al., 2009) Fertilizers approved for use in organic production a re available in granular, powder and liquid forms, and include plant based products (e.g. kelp and seaweed extract [19% K] soybean meal [7% N] ), animal based products (e.g. blood meal, bone meal [13% P] feather meal [13% N] hydrolyzed fish protein [10% N] bat guano [11% N] ) and natural deposits (e.g. rock phosphate, potassium sulfate, gypsum, sodium nitrate) (Organic Materials Review Institute 2010) Sodium (or Chilean) nitrate is the only allowed source of nitrogen that is a salt (and not a complex or ganic composite) and may provide no more than 20% requirement, however caution must be exercised with its use because its high sodium content can be detrimental to plant health ( Organic Materials Review Institute 2010 ; Sanchez and Richard, 2009 ) Citing increasing concerns of salt accumulation in soil, organic program, the USDA NOP is slated to remove sodium nitrate by November 2014

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27 (Tr eadwell et al., 2007) OMRI approved limestone and elemental sulfur can be used to adjust pH of soil/media and also provide a source of calcium, magnesium or sulfur ( Organic Materials Review Institute, 2010; Sanchez and Richard, 2009 ) While conventional h ydroponic greenhouse fertigation systems are designed to deliver an optimal balance of elements to the crop and allow for quick and precise adjustments throughout the season this synchronicity is difficult to achieve using organic nutrient sources. For ex ample, m any animal based composts and fertilizers have an excess of phosphorus and potassium relative to plant demand fo r nitrogen (Sanchez and Richard, 2009) Therefore, it is advantageous to use different organic fertilizers from a vari e ty of sources to attempt to provide enough of one element wit hout creating an accumulation or deficiency of another element (Greer and Diver, 2000 ; Sanchez and Richard, 2009 ) It is wise to test t he nutrient content of the media as well as the potential organic fertilizer/ compost inputs in order to make a more informed decision about the types and relative amounts of organic nutrient sources that will be needed to a chieve this balance of elements (Sanchez and Richard, 2009) However, different nutrients within the same orga nic nutrient source and between different organic nutrient sources are transformed into plant available forms at variable rates, and at much slower rates compared with inorganic fertilizers (some research claims that only 50% of total organic nutrients app lied will become available by the end of the season). Moreover different organic fertilizer sources have their own unique effects on the activity and health of the mineralizing and nitrifying microorganism populations in the media ( Chang et al., 2007; Mar inari et al., 2000 ) Therefore, it is extremely difficult to maintain the optimal balance among elements to avoid element interactions that can

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28 lead to deficiencies or toxicities And this proves to be particularly challenging in organic production of crop s, such as bell pepper, which are particularly N:K ratio (regulating vegetative vs. generative growth) sensitive. In conventional greenhouse production, mineral based fertilizers are often dissolved in water to create a nu trient solution that is then injec ted into the drip irrigation system with an automated proportional dosing pump and delivered to the plants with each irrigation event (known as fertigation). Liquid based organic fertilizers are relatively expensive, and both dry solution grade and liquid organic fertilizers do not dissolve co mpletely in water Nutrient solutions made with these products are primarily organic particles suspended in solution and cause clogging if delivered through the drip irrigation system ( Greer and Diver, 2000; Miles and Peet, 2002; Rippy et al., 2004 ; Zhai et al., 2009 ) hydroponic infrastructure and could potentially allow for quicker/easier adjustment of individual element levels and more precise contro l over nutrient delivery to meet plant demand throughout the season. Granular organic fertilizers, on the other hand, are less expensive and can be applied directly to the media thus avoiding clogging problems. However, they represent less control over nut rient delivery and could cause the electrical conductivity ( EC ) of the media to increase to levels detrimental to the plant (Rippy et al., 2004) Granular organic nutrient sources should be incorporated into the top 6 8 inches of the media because this is where most of the transforming micro organi sms reside (Sanchez and Richard, 2009) Other delivery methods of organic fertilizers i n the greenhouse include a media drench, foliar sprays and sub irrigation

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29 All factors considered, a variety of different organ ic fertilizers and their associated nutrient release rates and application strategies may be more successful than any one fertilizer or application strategy on its own. For example, organic sources of phosphorus are highly insoluble a nd so by incorporating high phosphorus containing granular sources directly into the media, relatively more soluble organic nutrients may be delivered through the irrigation system at dilute concentrations with less clogging issues (Miles and Peet 2002 ; Rippy et al., 2004 ) Ot her Organic Amendments There are other products approved for use in organic production that could prove beneficial for organic gr eenhouse nutrient management. I noculating media with biological amendments like plant growth promoting bacteria (Rhizobacteria) and fungi (Mycorrhizae) has been shown to enhance nutrient uptake and utilization in organic transplant production (Kokalis Burelle et al., 1999; Ortas et al., 2009 ; Russo, 2006 ) However, its usefulness in long term production has been debatable as it is still unclear if the benefits they provide translate into higher yields that justify the extra production cost. These biological amendments are either already incorporated into organic fertilizers or sold separately to be applied by foliar spray or soil d rench ( Organic Materials Review Institute 2010) Fulvi c acid is an amendment that is marketed to increase nutrient holding capacity of media, chelating ability and plant uptake of micronutrients. Other products marketed as increasing plant health, plant flowering, media microbial activity and/or disease suppression are chitin, humic acid, enzymes and molasses.

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30 Fertigation System S trategies Due to insolubility of organic fertilizers, attempting to deliver them through the greenhouse hydroponic drip irrigat ion system s will commonly result in clogging of the irrigation lines and emitters. Therefore, it may be advantageous to use irrigation lines with larger diameter and emitters with higher flow rate than what is typically used in conventional greenhouse irri gation systems in an attempt to avoid (or at least reduce the severity of) futu re clogging issues (Miles and Peet 2002 ; Rippy et al., 2004). In conventional fertigation systems, it is recommended to periodically deliver only water through the lines for a short time period in order to flush the lines and dislodge mineral d eposits. It may be even more important to do this in organic fer t igation systems to help alleviate clogging issues by flushing any particulates, algae or microbial sludge deposited in the lines (Rippy et al., 2004) S olubility of some conventional mineral fertilizers can be enhanced by changing the pH or temperature of the nutr ient solution Typically, acidification can improve the solubility of organic nutrient sources While there are sev eral acidic products that can be added to nutrient solutions in conventional production, there are very few acidic products that are OMRI approved in organic production, the most common of them being citric acid ( Organic Materials Review Institute 2010) However, growers must be careful to balance the pH in the nutrient solution and root environment so as to prevent nutrient imbalances and maintain the health of the crop and transforming bacteria. O rganic nutrient solution should be made more frequently a nd more dilute than conventional fertilizer nutrient solution in order to avoid excess precipitates in the solution that can clog the fil ters on the fertigation pumps (Miles and Peet 2002 ; Rippy et al., 2004)

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31 Previous Organic Greenhouse Production (Comm ercial and Research) Because of the inherent difficulties in organic greenhouse nutrient management, previous research studies and commercial operations have focused on crops that compared to bell pepper are less demanding (e.g. tomato) or short er season ( e.g. tomato, herbs, lettuce and transplants), and it is difficult to extrapolate these finding to other crops and systems (Treadwell et al., 2007) However, p revious published research on organic greenhouse production in general is limited and is particu larly scarce for intensive, nutrient demand ing N:K ratio sens itive, relatively long season crops such as bell pepper. And while practices of organic greenhouse production in soil have been documented, specific practices for preparing organic fertilizer mi xes for hydroponic systems, injecting the mix through the drip irrigation lines and adding composts to soilless media for crop production are not adequately described (Rippy et al., 2004 Zhai et al. 2009 ). The fact is there are few, if any, tu rnkey protoc ols for successful organic greenhouse production. However began reporting on U.S. imports of organic greenhouse grown colored bell peppers from Israel in December 2004 and currently th e site repo rts on th is commodity being imported into the U.S. from the Netherlands, Mexico, Spain, the Dominican Republic, and Canada as well ( U.S. Dept. of Agriculture, 2012a ) Therefore, s uccessful organic greenhouse production of bell pepper is possible and it can potentia lly be a very lucrative market for U.S. growers Results of previous organi c greenhouse research are variable. A mending soil or soilless media with organic composts derived from yard, dairy, poultry, swine, worms or greenhouse operation wastes can improve porosity, water holding capacity and biological activity of the media, however the nutr ient content of these composts were

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32 typically too low and beca me av ailable too slowly to sustain plant gro wth and productivity without added fertilizer sources. ( Chang e t al., 2007; Kraus and Warren, 2000; Zh ai et al 2009). Zhai et al ( 2009 ) produced organic greenhouse tomato yields of 80 100% of the conventional hydroponic greenhouse control using peat and perlite media amended with 40 50% swine, yard waste or mushroo m compost and organic plant based liquid feed mixed with organic potash, calcium carbonate and dolomitic lime delivered through the irrigation system starting at transplant or 30 days after transplant This study showed that compost type did not affect yie ld, but plant based organic liquid feed produced higher organic yields than fish based organic liquid feed, and low liquid feed concentrations produced higher yields and less disease incidence than high liquid feed concentrations (Zhai et al., 2009). This study also showed higher biological activity in compost amended media compared to the no compost control, and in the organic liquid feeds compared to the hydroponic conventional feed (Zhai et al., 2009). Heeb et al. (2006) showed lower yields from organic compared to conventional treatments in both field and greenhouse tomato crops. Rippy et al., 2004 used v arious liquid orga nic fertilizers, comprised of bat guano, Norwegian sea kelp, natural sulfate of potash, feather meal, oat bran, blood meal, steamed bo ne meal, Chilean sea bird guano, rock phosphate, wheat malt, molasses, yeast, kelp meal, seaweed, poultry compost tea and calcium phosphate. These fertilizers were hydroponically fertigated to organic greenhouse tomato plants grown in peat and pine bark su bstrate amended with various amounts of vermicompost, blood mea l, bone meal, potassium sulfate, dolomitic lime and elemental sulfur, producing variable results from year to year and substantial clogging problems but some organic regimes produced yields co mparable to

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33 conventional in the final year of the experiment ( Miles and Peet, 2002; Rippy et al, 2004). Organic greenhouse grown mature green indeterminate (214 day season from transplant) bell pepper plants grown in soil amended with horse manure as th e only source of nutrients produced variable results as well (del Amor, 2007; d el Amor et al., 2008) In 2007, Del Amor showed decreased plant biomass and [NO 3 N] but similar marketable yields from organic bell pepper plants compa red to conventionally ferti lized plants. Organic greenhouse basil planted in either perlite or peat/perlite/compost media and fertigated with an organic nutrient solution made of fermented poultry compost, hydrolyzed fish emulsion, kelp extracts, and soft rock phosphate produced yie lds comparable to that of greenhouse basil plants gro wn conventionally (Succop and Newman 2004). Schwankl and McGourty (1992) demonstrated successful fertigation and minimal clogging with organic spray dried fish and poultry protein fertilizers injected t hrough drip and micro sprinkler systems and Greer and Diver (2000) claimed liquid organic fertilizers made of fish and seaweed blends were popular among organic growers using drip systems. Hartz et al. (2010) found that fish, guano and plant based liquid organic fertilizers mineralized /nitrified under an incubation study and were made plant available in a n organic soil based greenhouse bioassay study with fescue at a much faster rate than dry organic fertilizers and composts. In this sense, they functioned similarly to conventional nitrogen fertilizers and Chilean nitrate. However they found these liquid organic fertilizers to be cost prohibitive and unsuitable for application through drip irrigation systems due to clogging and so could not form the basis f or an organic nitrogen fertility plan.

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34 Organic Greenhouse Production of Red Bell Pepper Economic Analysis There are oftentimes high costs associated with modern greenhouse technology ( Cantliffe et al., 2008; Jovicich et al., 2005 ) many organic inputs and USDA c ertification of organic systems. Furthermore, t he list of products approved for use in organic production are limited and variable in effectiveness ( Organic Materials Review Institute 2010) the USDA regulations are ever changing and the yields of produce from organic production systems are often lower compar ed to yields from conventional systems. However, as demand for and price premiums associated with colored, greenhouse grown and organic bell pepper increase, combining these aspects into a succe ssful organic greenhouse grown red bell pepper operation presents itself as a potentially lucrative fresh market niche for growers to expand into As a result, economic analysis of organic greenhouse production of red bell pepper is needed to determine if the benefits of the system outweigh the costs. Prices of c olored bell pepper can be two times higher than green bell pepper, greenhouse grown bell pepper can be three to five times higher than field grown pepper and organic produce can be more than two ti mes higher than conventional produce (Jovicich et al., 2005 ; U.S. Dept. of Agriculture, 2012a ) The yield and quality increases associated with growing in a greenhouse compared to the open field will be especially important in attempting to offset the typi cally lower yields associated with organic production. Organic greenhouse grown red bell pepper s in the U.S. are typically imported from Israel, the Netherlands, Mexico, Spain, the Dominican Republic, and Canada, with only a very small proportion supplied from domestic operations ( U.S. Dept. of Agriculture, 2012a ) The steadily high market prices, the increases in consumer demand for this product and the lack of domestic supply highlights the potential for U.S.

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35 growers to expand into this market niche, espe cially for growers in F lorida where climate is mild and protected agriculture area is increasing. Because many conventional greenhouse growers use soilless hydroponic systems, it may be beneficial to use their existing hydroponic infrastructure and materia ls and modify it for successful organic greenhouse production. By adapting the existing greenhouse system, the costs of transitioning from conventional to organic production would be minimized. Greenhouse systems vary considerably in size, technology and i nfrastructure, and there are studies that explore the economic viability of conventional red bell pepper grown in different greenhouse structures. However, to our knowledge, there have been few studies examining how organic nutrient management systems dire ctly affect the vi ability of organic production of red bell pepper in these greenhouse structures, in terms of both costs and returns. Florida growers interested in organic greenhouse production of red bell pepper need information based on local production systems. While many organic nutrient and media inputs can be expensive, it will important for growers to use sources that are relatively less expensive and, in keeping with organic philosophy, use resources that are local and available in enough supply to be used in large commercial greenhouse operations in order to cut down on costs and keep the operation profitable. The purpose of this study was to determine the nutrient management costs in producing organic r ed bell pepper in a mid level Florida greenho use for fresh market and estimate the economic return with expected yields for growers interested in this market. Sensitivity analyses were performed to assess and compare the economic feasibility of growing organic vs. conventional greenhouse red bell pep per. These analyses were developed

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36 using fruit yield information from the greenhouse trials of red bell pepper grown under different organic and conventional greenhouse nutrient management systems. Objectives and Hypothesis Certification agencies across th e U.S. are certifying greenhouses for organic transplant and specialty crop production, due primarily to the requirement for organic transplants in the Final Rule of the USDA National Organic Standards (U.S. Dept. of Agriculture, 2012b) Because of the inh erent complexities and costs, very little research has been dedicated to discovering the most effective combinations of media, fertilizer source and application strategies for successful organic greenhouse production of bell pepper. By managing for nitrify ing bacteria, selecting plant and animal based fertility amendments, and using locally sourced materials to the fullest extent possible, we anticipate an increased profit potential for growers of organic greenhouse bell pepper. Four organic greenhouse nut rient management regimes and their associated application strategies were developed, assessed and compared with one another and with conventional greenhouse nutrient management regime in terms of their production potential and economic practicali ty. We pro pose that these media and fertilizer combinations will significantly contribute to our confidence in recommending nutrient management strategies for sustainable, organic greenhouse colored bell pepper production. The objectives of this project we re to : 1. Ide ntify the combination of media, fertilizer source and application strategy that will grow organic ally managed greenhouse colored bell pepper plants which produce the quantity and quality of fruit similar to conventional ly managed hydroponic greenhouse colo red bell pepper plants. 2. Conduct a partial cost benefit analysis of the best performing conventional and organic treatments in order to determine their economic practicality for growers

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37 In support of these objectives, two hypotheses were developed and are: 1. An organic greenhouse colored bell pepper nutrient management strategy that can produce yields comparable to that of a crop grown under conventional greenhouse hydro ponic systems will include: a) an organic compliant soilless media mix amended with animal based compost to sustain essential transforming microbes; and b) a combination of several organic compliant nutrient sources applied both granularly and through the irrigation system. 2. Potential yield reductions associated with organic production methods w ill be offset and exceeded by : a) high price premiums for bell pepper that is greenho use grown, organically grown and harvested red; and b) using a variety of organic media and fertilizer inputs that are relatively low cost and locally sourced.

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38 CHAPTER 2 EVALUATION OF GROWING MEDIA, FERTILIZER SOURCE AND NUTRIENT APPLICATION STRATEGIES FOR AN EFFECTIVE ORGANIC GREENHOUSE BELL PEPPER NUTRIENT MANAGEMENT SYSTEM Materials and Methods Site Description The experiment was conducted in Fall 2010 and Spring 2011 in a multi bay, 2023 m 2 passively ventilated, saw tooth style greenhouse (Top Greenhouses Ltd., Barkan, (UF) Plant Science Research and Education Unit (PSREU) in Marion County, near Citra, FL (Figure 2 1) Th e high roof structure is covered with UV absorbing polyethylene film, the ventilated side walls and roof vents are covered with 50 mesh insect screen and the floors are covered in white landscape fabric. The experiment was established in one bay of the gre enhouse, where 0.15 m diameter polyvinyl chloride (PVC) pipe s were placed in four rows (1.2 m apart) down the north south length of the greenhouse to serve as a drainage system (Figure 2 2) Because the experiment contained a conventional fertilizer treatm ent for comparison, the greenhouse was not certified organic. Pest management was achieved using biological control methods as described below, and no prohibited pesticides were applied in the greenhouse for six months prior to and during the course of the experiment. Experimental Design Overview An experiment was arranged as a randomized complete block design with treatments replicated four times to evaluate the effects of fertilizer and media source and form epper (Osborne Seed Company,

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39 Mount Vernon, WA) in Fall 2010 and Spring 2011. Treatments were a factorial combination of five fertilizer treatments (one conventional hydroponic and four organic compliant) and three compost treatments (no compost, 30% yard w aste compost or 30% poultry litter com post) for a total of 15 treatments. X3R Red Knight F1 was used because it is a top yielding and top quality determinate variety well adapted to Florida climate (Shuler, 2003) which could potentially be grown in three crops per year (spring, summer and fall); it is resistant to Bacterial Leaf Spot ( Xanthomonas axonopodis pv. vesicatoria races 1 3), Tobacco Mosaic Virus and Potato Virus Y strain which is important in an organic compliant growing system that does not use chemicals for disease suppression; and it is an early mid maturing variety which would allow growers to target specific market windows. On 13 Sept. 2010 and 9 Mar. 2011, b ell pepper seedlings were transplanted into 11.4 L black polyethylene nursery pots ( C1200, BWI Co Inc Apopka, FL) with two 1.5 cm diameter drainage holes drilled equidistant from each other and 3.8 cm from the bottom of the pot to create a reservoir (Figure 2 3 a ) Cut squares of nylon s creen covered the holes from the inside of each pot to prevent media loss Pots were placed on the four rows of PVC pipe, and each row of pipe comprised one block of the experiment (Figure 2 3b ) P lots contained six plants (one plant per pot) arranged in rows, for a total of 60 plots and 360 plants. Plants within each row were 30 cm apart and between row spacing was 120 cm from center to center for a plant density of three plants per m 2 The center four plants in each plot were harvested by hand on 2 and 9 Dec 2010 [80 and 87 days after transplant (DAT) re spectively ] and 18 May 25 May and 7 June 2011 (70, 77 and 90 DAT respectively )

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40 Fertilizer treatments The conventional hydroponic fertilizer ( Convtl ) consisted of a custom mix of mineral based fertilizers (Table 2 1 ) and was injected through the irriga tion system throughout the season based on a nutrient levels and irrigation schedule formulated for hydroponic greenhouse grown bell peppers (Table 2 2 ) (Jovicich et al. 2004). The organic granular fertilizer ( Gran ) consisted of a custom mix of four OMR I approved sources (Table 2 1 ) and was incorporated directly into the media either at transplant or at sidedress depending on the treatment The organic fertilizer solution ( Soln ) consisted of a custom mix of three OMRI approved sources (Table 2 1 ) and w as injected through the irrigation system beginning either at transplant or at sidedress depending on the treatment Sidedress fertilizers were applied on 13 October 2010 (30 DAT) and 9 April 2011 (31 DAT) The five fertilizer treatments were as follows: C onvtl: mineral based; beginning at transplant ing and applied throughout the season (Table 2 2 ) Gran Gran: organic; Gran applied at transplant ing Gra n applied at sidedress (Table 2 3) Gran Soln: organic; Gran applied at transplant ing Soln beginning at sidedress (Table 2 3) Soln Gran: organic; Soln beginning at transplant ing Gran applied at sidedress (Table 2 3) Soln Soln: organic; Soln beginning at transplant ing and applied throughout the season (Table 2 3) Total season applications of nitrogen ( N ) phosphorus ( P ) potassium ( K ) and calcium ( Ca ) were consistent across all treatments (i.e., 10, 2 20 3 5 13 13,365 and 11,692 m g per plant, respectively).

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41 In conventional greenhouse hydroponic fertigation production systems all nutrients are typically metered out via the irrigation system with each irrigation event throughout the season allowing precise control over nutrient applications and calcium is usually injected separately from phosphorus and sulfur because they precipitate when mi xed together I n field production systems that utilize fertigation most, if not all, of the phosphorus is applied in granular form at planting because it is relatively less soluble (especially if it is derived from organic sources) and can clog the irrig ati on system if injected In field systems, at least half of the nitrogen and potassium are applied in granular form at pla nting, but the other half is inject ed through the irrigation system so that the nutrient supply can be controlled and adjusted accord ing to plant demand during the season An advantage shared by both the greenhouse and field fertigation method s is the reduced risk of fertilizer leaching and salt toxicity in young plants because these methods supplant heavy fertilizer applications earl y in the season The application timing and strategies of the organic fertilizer treatments in this study ( Table 2 2, Table 2 3 ) were based on these basic principle s in addition to the goal of keep ing total season N P K and Ca consistent across treatmen ts. Application of Convtl fertilizer. Two fertilizer proportional injectors ( MiniDos 2.5%, Dosmatic U.S.A., Inc, Carrollton, TX) placed in series were used to pump mineral based stock solution into the irrigation water (dilution rate 1:50; v/v) from t wo 18. 9 L buckets according to conventional hydroponic greenhouse practices that keep calcium separate from both phosphorus and sulfur to prevent precipita tion (Figure 2 4 ) Application of G ran fertilizer. A t transplanting the Gran fertilizer was incorporat ed into the top 15 cm of the media in the pots. The depth was chosen

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42 because it is the most biologically active zone for transforming organic sources of nutrients into plant available forms At sidedress, the Gran fertilizer was incorporated into the top 8 cm to avoid damaging plant roots. Application of Soln fertilizer. A fertilizer proportional injector was used to pump organic stock solution into irrigation water ( dilution r atio 1:50; v/v) from an 18.9 L bucket for each of the three fertil izer treatm ents involving Soln (Figure 2 4 ) To reduce the incidence of clogging, new organic stock solutions were made weekly emitters were frequently checked for clogging and flushed out, the dilution ratio of 1:50 was chosen to feed a less concentrated fertiliz er solution and all filters wer e cleaned at least twice a week (Rippy et al., 2004 ; Zhai et al., 2009 ) Compost treatments All pots received a media base mix of 1 peat : 1 pine bark (by volume ). The OMRI approved peat (Sunshine Peat Moss; Sun Gro Horticult ure Canada Ltd, Orlando, FL) was custom mixed with dolomitic limestone for a target pH between pH 5.5 and pH 6.5. The OMRI approved p ine bark (Elixson Wood Products, Starke, FL) was screened to a size less than 2.5 x 2.5 cm. The three compost treatments we re as follows: NC: no compost YW: 30% yard waste compost by volume PL: 30% poultry litter compost by volume The OMRI approved yard waste compost was locally sourced (Gainesville Wood Resource and Recovery, Gainesville, FL) and screened to 0.95 cm The pou ltry litter compost was sourced from a local organic farm certified by Quality Certification Services, Gainesville, FL ) and was composed of 100% poultry manure and pine sawdust from a neighboring poultry producer. The compost

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43 w as screened to 1.27 cm Relevant chemical and physical properties of the peat, pine bark, yard waste compost and poultry litter compost media components are presented in Table 2 4 Relevant properties of the NC, YW and PL custom made media mixes t hat represent the compost treatments are presented in Table 2 5 Irrigation system Untreated well water was used for irrigation. W ater was delivered through black 1.9 cm diameter poly ethylene pipe ( John Deere Landscapes, Gainesville, FL) with or without fe rtilizer depending on the treatment. Previous studies ( Rippy et al., 2004; Zhai et al., 2009) have found that typical hydroponic greenhouse emitters with a flow rate of 1.9 L /h or less are readily clogged by fertilizer solutio ns made from organic sources; therefore in this study, e ach plant rec eived the irrigation through a 7.6 L /h pressur e compensated emitter on the end of a 60 cm long spaghetti tube (Figure 2 5 ) Other measures taken to avoid clogging issues included using polyethylene pipe and spaghetti tubing with diameters larger than normal for hydroponic greenhouse operations incorporating three filters before the fertilizer proportional injectors in order to filter out particulates from the well water and drawing each stock solution u p through its own filter Irrigation duration and frequency was automated using a timer was consistent across all treatments and was increased over the course of the season to meet plant demand (ranging from 300 to 1500 mL/plant/day). Although the fertilizer proportio nal injectors were all operated on the same timer each was connected to its own solenoid and separate program on the timer to allow them to run individually and avo id reductions in pressure (Figure 2 4 )

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44 Crop Seasonal Management Transplant production Untr epper seeds were sown in Sunshine organic planting mix (Sun Gro Horticulture Canada Ltd, Tampa, FL) in plastic 72 cell transplant flats. The seedlings were grown in two controlled environment chambers (width x depth x height : 183 x 76 x 102 cm; Conviron, Controlled Environments Limited, Winnepeg, Manitoboa, Canada) fitted with fluorescent and incandescent bulbs on the main campus of UF beginning on 16 July 2010 and 6 January 2011. The photoperiod was set at 14:10 day/night an d the temperature was set at 25C until germination and then used 22C/20C day/night and 25C/22C day/night programs until transplant (Cruz Huerta, 2010 ; Saha and Cantliffe, 2009 ). The seedlings were fertigated as needed after the expansion of the first true leaf using a n utrient solution made with 20 8.8 16.6 (%N %P %K) Multipurpose Professional Water Soluble Plant Food (Plant Foods, Inc., Vero Beach, FL). Temperature control and trellising Throughout the season, the greenhouse polyethylene s ide curtain s were manually lowered when air temperatures were less than 18C or during periods of rainfall and were raised when a ir temperatures were greater than 25C. T hermal tubes (Polyon, Barkai, Israel) and aluminized thermal screens were used when air temperatu res were less than 10C (Jovicich et al., 2005 ; Jovicich et al. 2007 ). In high temperatures, fans were used to improve air circulation. All plants were trellised in a modified Spanish system as the plants were a determinate growth structure (Jovicich et al., 2004; Saha and Cantliffe 2009). Pairs of vertical poles and horizontal twine supported the plants on both sides of the rows and twine was placed every vertical 20 cm as the plants grew

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45 Integrated pest management practices No chemical means of pest co ntrol were used in this study Plants were scouted on a weekly basis or more often as needed to identify disease occurrence and inc reasing pest thresholds. Pests were controlled using integrated pest management (IPM) practices, including biological cont rol with banker plant systems and alternate hosts that help to sustain beneficial insect populations but do not negatively affect bell pepper crops ( Jovicich et al., 2004; Osborne and Barrett 2005 ; Saha and Cantliffe 2009 ; Shaw and Cantliffe 2002). Alte rnate host g rain aphids were reared on sorghum banker plants in order to sustain the beneficial parasitic wasp colonies ( Aphidius colemani ) that control the aphid pests. Alternate host papaya whiteflies were reared on papaya banker plants in order to susta in the beneficial parasitic wasp colonies ( Encarsia formosa and Eretmocerus eremicus ) that control the whitefly pests. Alternate host g rass mites were reared on sorghum banker plants in order to sustai n the beneficial predatory mite colonies ( Amblyseius sw irskii Neoseiulus cucumeris and Neoseiulus californicus ) that control mite and thrip pests. Additionally, sticky cards were used to trap winged pests such as fungus gnats and diligent sanitation habits were observed during the course of the season. Bumbl ebees ( Bombus im patiens ) were introduced for supplementary pollination to aid in fruit set; one bee hive per season serviced 650 to 1115 m 2 (Jovicich et al. 2004; Saha and Cantliffe, 2009; Shaw and Cantliffe 2002 ) Beneficials ( i.e., Aphipar, Enermix, Sw irski Mite, Thripex V and Spical) and bumblebees ( i.e., NATUPOL class B ) were acquired fr om Koppert Biological Systems in Romulus, Michigan. The seedlings were transplanted to the depth of the cotyledonary node level and the emitter placed at the base of the seedling at transplant was gradually moved back

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46 from the base of the plant over the cou rse of 4 weeks. These IPM measures were taken which could predispose the plants t o a Fusarium infection (Jovicich and Cantliffe, 2004 ) Data Collection Measurements during the growing s eason Inside the greenhouse, air temperature at a height of 1 meter and the temperature of each of the three media/compost mixes was measured with thermo couples (PR T 24 Omega Engineering, Stamford, Conn.) and recorded every 15 minutes using HOBO data loggers (CR10X; Campbell Scientific, Logan, Utah) beginning on 12 Oct. 2010 (Jovicich et al. 2007; Saha and Cantliffe 2009) (Figure 2 6 ) Onl y Fall 2010 te mperature data are presented. T he equipment malfunctioned in Spring 2011 and the dat a could not be retrieved from the recorder On 30 Sept. and 23 Oct. 2010 ( 17 and 40 DAT respectively ) and on 30 Mar., 22 Apr., 4 May and 6 June 2011 (21, 44, 56 and 89 DAT respectively ), plant height was measured from the media surface to the last node of the tallest stem on each of the four center plants in each plot (Table s 2 12 and 2 13 and Figures 2 18 and 2 19 ) On 30 Sept., 23 Oct., 12 Nov. and 8 Dec. 2010 (17, 40, 6 0 and 86 DAT respectively ) and on 30 Mar., 22 Apr., 4 May and 6 June 2011 (21, 44, 56 and 89 DAT respectively ), a SPAD value from the most recently fully expanded leaf of the four center plants in each plot was measured using a SPAD 502Plus chlorophyll m eter (Spectrum Technologies, Plainfield, IL) (Table s 2 12 and 2 13 and Figure 2 20 ) The a representation of leaf nitrogen status.

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47 Leachate sampling and a nalysis On 12 Oct., 11 Nov., and 14 Dec. 2010 (29, 59 and 92 DAT respectively ) and on 8 Apr., 30 Apr. and 21 May 2011 ( 30, 52 and 73 DAT respectively ), leachate samples were collected from one of the center four plants in each plot by the pour through nutrient extraction procedure (Rippy e t al., 2004) At the time of collection, the pH and electrical conductivity (EC) of the samples were measured using a Hanna Waterproof pH/Conductivity/TDS tester (HI 98129 and HI 98130 ; Hanna Instruments, Smithfield, RI). Each sample was then transferred t o a 20 mL scintillation vial, filtered and acidified with a 50% sulfuric acid solution to between pH 1 and pH 2, and frozen at 4C ( Florida Dept. of Environmental Protection 2010 ; Mylavarapu et al. 2010 ) until analyzed for nitrate (NO 3 N) concentration b Laboratory using standard procedures (EPA M ethod 353.2) (Mylavarapu and Kennelley, 2002). Leachate pH, EC and nutrient analyses are presented in Table s 2 14 and 2 15 and Figure 2 21 Tissue sampling and a na lysis At harvest, tissue samples of the most recently fully expanded leaves were collected from the four center plants in each plot and combined into one composite leaf sample per plot. Also at harvest one bell pepper was randomly selected from each of th e four center plants in each plot, cores and seeds were removed and the flesh was diced and combined into one composite fruit sample per plot. Leaf and fruit tissue samples were dried at 70C until a constant weight was measured, ground in a Wiley mill (Th omas Scientific, Swedesboro, NJ) to pass through a 20 mesh sieve, and anal yzed for total kjeldahl n itrogen (TKN) concentration using a Bran+Luebbe

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48 Technicon AutoAnalyzer II segmented flow analysis system (EPA Method 351.2) (Hochmuth et al. 1991) Fresh an d dry weight s of the fruit samples were recorded and used with the fruit TKN analysis data to determine fruit nitrogen use efficiency (NUE). In the experiment, NUE is defined as the perce ntage of applied nitrogen that wa s removed at the end of the season b y the harvested bell peppers. NUE was calculated using Equation 1 1 described by Zvomuya et al. (2003) : NUE = 100 (N treat / N applied ) (1 1) In Equation 1 1, N treat represents the amount of nitrogen removed in the fruit sample of a given treatment (i.e., fruit nitrogen uptake), and N applied is the amount of nitrogen applied as fertilizer in that treatment (i.e., N rate). Calculations of N treat used total yield values. After all peppers were harvested, whole plant samples were collected by removing the cent er four plants of each plot at the media surface dried at 70C until a constant weight was measured and weighed to determine aboveground biomass accumulation per plant Leaf percent TKN, whole plant dry weight and pepper f ruit fresh weight, dry weight, pe rcent TKN and percent NUE at harvest are presented in Tables 2 16 and 2 17 and Figures 2 22 and 2 23. Harvest Bel l pepper fruit were harvested by hand on 2 and 9 Dec 2010 (80 and 87 DAT respectively ) and 18 May, 25 May and 7 June 2011 (70, 77 and 90 DAT respectively ). Using a slide ruler, all pepper s on the center four plants of each plot were graded by size according to a fresh market diameter scale used for imported greenhouse grown bell peppers (Jovicich et al., 2004 ; Saha and Cantliffe, 2009 ) Marketa ble fruit were

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49 graded as extra large ( XL diameter 84 mm), large ( L = 75 to 83.9 mm), medium ( M = 65 to 74.9 mm) or small ( S = 55 to 64.9 mm) with no serious external defects. Unmarketable fruit were less than 55 mm in diameter or had at least one of the six major bell pepper external defects: blossom e nd rot, sunscald, r adial cracking, flat shape, mis shapen or russeting. Weight and number of fruit in each of the five size categories and six cull categories were recorded per plant. The number of lobes was counted on each pepper harvested and averaged per plant (Tables 2 16 and 2 17 and Figure 2 24 ) T he four sample peppers per plot collected for TKN analysis were sliced at their equator where pericarp thickness was measured using a Venier caliper (Bel Art Products, Pequannock, NJ) (Tables 2 16 and 2 17 ) Total and marketable pepper yield data in kg/m 2 are presented in Tables 2 6 and 2 7 and Figures 2 7 through 2 10 Pepper quality data in kg/m 2 are presented in Tables 2 8 and 2 9 and Figures 2 11 and 2 12 Pepper yield and quality data in number of fruit p er m 2 and percent of total yield by weight are presented in Tables 2 10 and 2 11 and Figures 2 13 through 2 17 Statistical Analysis Combined analyses of variance (ANOVA) among years (Fall 2010 and Spring 2011) indicated significant treatment and year inte ractions This may have been attributed to the season al variation in growing conditions and the resulting differences in irrigation scheduling as well as to the minor adjustments made when the study was repeated in Spring 2011. Therefore separate statistic al analyses for each year were conducted to evaluate the effect of fertilizer treatment, compost treatment and their interaction on organic greenhouse grown bell pepper production. Statistical analyses to evaluate main and interaction effects were performe d using SAS General Linear Model

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50 (GLM) software (V.9.2 S AS Institute, Cary, N.C.). east significance difference (LSD) tests with P 0.05 were employed for means separation among treatments. Significant interaction effects were sliced by fertiliz er treatment to enable the comparison of the compost treatments among each of the fertilizer treatments, and were sliced by compost treatment to enable the comparison of the fertilizer treatments among each of the compost treatments. Although plant height, plant SPAD values, plant dry weight at harvest, lobe number, pericarp thickness and yield and quality data were collected per plant, the values were averaged per plot before statistical analyses in order to reduce within treatment variation. Composite fru it sample fresh and dry weight, leaf and fruit percent TKN and the pH, EC and [NO 3 N] of leachate data were measured per plot. Results and Discussion Cultivar Selection Just as cultivar performance changes with climate (i.e. cultivars performing better in one region than another) different cultivars may perform better than others under organic greenhouse nutrient management. X3R Red Knight F1 was chosen for this experiment because of its demonstrated adaptation to Florida climate and to containerized green house growing environments, its disease resistance (which is important since there is limited available/effective products for pest/disease control in organic production) and its market desirability and mature red color which will demand high premiums (Sh uler, 2003) Of the different mature bell pepper colors, red was chosen because research has demonstrated that red bell pepper plants achieve higher yields than the other colors (Cantliffe et al., 2008) While indeterminate bell pepper

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5 1 cultivars with 10 mo nth long seasons are often grown in greenhouses, a determinate cultivar was chosen for this study for the following reasons: Clogging of the hydroponic greenhouse fertigation system s by organic nutrient sources worse ns with time, so using a determinate var iety creates shorter crop season s (less liability) between which the fertigation lines can be thoroughly cleaned and reused for the next crop season Since it is a three to four month crop from transplant to harvest, growers could potentially produce thre e bell pepper c rops per year corresponding to spring, summer and f all reusing materials such as media, pots and irrigation lines; or it or during non peak production times in the abs ence of market competition Therefore, it is important to keep in mind that the yields discussed in this study reflect those of a determinate 4 month long crop per season with one to two harvests and so will naturally be lower than typical yields reported for greenhouse bell pepper production of an indeterminate 10 month long crop per season with up to 30 harvests. Air and Compost Treatment Temperature and Chemical/Physical Properties The physical and chemical properties of the four media components (peat, pine bark, yard waste compost and poultry litter compost) and of the three custom media mixes that represent the compost treatments (NC, YW and PL) are shown in Table 2 4 and 2 5, respectively). The physical and chemical characteristics of the substrate ca n potentially affect plant yield. Poultry litter compost had substantially higher soluble salt, sodium and potassium content than the peat, pine bark and yard waste compost, resulting in higher soluble salt and potassium content of the PL compost treatment This could potentially result in high EC and salt salinity stress which could negatively affect bell pepper yields (Zhai et al., 2009) Ideal EC range for bell pepper is 1.5 to 2.5 mS/cm. Poultry litter compost also had higher phosphorus content resultin g in higher phosphorus concentration in the PL compost treatment, which could potentially limit

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52 calcium availability through precipitation reactions (Zhai et al., 2009 ) Bulk density is the mass of soil/media per unit of volume and includes air space and m ineral plus organic materials, and is used to determine if soil/media layers are too compact to allow root penetration or adequate aeration (Evanylo and McGuinn, 2009). Similar to results reported by Zhai et al. (2009) and Treadwell et al. (2007) bulk den sity of the YW and PL compost treatments (0.37 and 0.33 g/cm 3 respectively) was about twice that of the NC control (0.19 g/cm 3 ) most likely because of the lower percent organic matter and fine particle size of the poultry litter and yard waste compost co mpared to the peat and pine bark base media components. However, all are within acceptable range. Percent cation exchange capacity (CEC) of the NC, YW and PL compost treatments was 55, 38 and 32%, respectively and represents their nutrient holding capacit y Media with higher organic mat ter and CEC and lower bulk density i mproves the media quality (Bullu ck et al., 2002). Although PL and YW compost treatments had higher pH than NC (similar to results reported by Zhai et al., 2009) it was still in acceptable media pH range for bell pepper production ( pH 5.5 pH 7 .0 ) Reflecting the lower c arbon to nitrogen ( C:N ) ratio of the organic treatments compared to the conventional hydroponic control in Zhai et al. (2009), C:N ratio of the peat, pine bark, yard waste compost and poultry litter compost was 64:1, 121:1, 25:1, and 7:1, respectively Since peat and pine bark have a high C:N ratio (>30) the NC treatment could have led to nitrogen immobilization in the media mix, making it unavailable for plant uptake, and rendering any of the combinations of organic fertilizer treatment with NC compost treatment ineffective in terms of yield (Paul and Clark, 1996 ; Sanchez and Richard, 2009 ) Microbes will compete with plants for

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53 nitrogen when media is amended with products having C:N ratios higher than 25:1 or 30:1 (Evanylo and McGuinn, 2009 ; Sanchez and Richard, 2009 ). Since the poultry litter compost has a low er C:N ratio than the yard waste compost (<20) it could potentially mineralize organic nitrogen into plant availab le form at a faster rate resulting in higher yields for organic fertilizer x PL compost treatment combinations (Sanchez and Richard, 2009) However, C:N ratio of the media mix would not likely be a yield determining factor in compost treatments paired wit h the conventional hydroponic fertilizer treatment because the mineral based fertilizer is providing plant available forms of nutrients with every fertigation event. Percent water holding capa city of NC, YW and PL compost treatments was 56, 71 and 91%, res pectively. Ideal water holding capacity (or water filled pore space) is considered to be within the range of 50 70%. Because the poultry litter compost increased the water holding capacity of the media to 90%, it is important to not over irrigate, reducing the oxygen filled pore spaces that are necessary for nitrification reactions (Evanylo and McGuinn, 2009 ; Treadwell et al., 2007 ). In general, poultry litter compost had higher nutrient concentrations than yard waste compost, and both composts had higher n utrient concentrations than the peat and pine bark base media components. As a result, compost/media treatment nutrient concentrations followed the pattern PL > YW > NC. However, the organic sources of nutrients in composts are relatively low (e.g. only 0. 3% and 1% total nitrogen in the yard waste and poultry litter compost, respectively) and mineralized into plant availab l e forms at such a slow rate (10 20% per year for nitrogen is commonly assumed) that it is unlikely these nutrient content differences i n the media treatments directly affected yield (Sanchez and Richard, 2009 )

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54 The high temperature, low temperature and average temperature of the air inside the greenhouse at a height of 1 m and the NC, YW and PL compost treatments throughout the Fall 2010 season beginning at 29 DAT is presented in Figure 2 6. Optimum soil temperature is considered to be within the range of 25 35 C, but substrates tend to reach higher temperatures than soil. These graphs show the temperature buffering capacity afforded by th e composts, with YW and PL substrates maintaining lower temperatures than the air and NC in the high temperature graph, and YW and PL substrates maintaining higher temperatures than air and NC in the low temperature graph. Of the two composts, poultry litt er seems to have slightly greater temperature buffering capacity than yard waste compost. The temperature buffering capacity of the YW and PL compost treatments could be partly due to the higher water holding capacity of the composts and could potentially give plants a growing advantage by keeping the environment surrounding the roots more stable. The ideal day air temperature for bell pepper plants during fruit set is 18 22 C. However night temperatures are more crucial and must stay above 10 C during frui t set. Bell Pepper Yield and Size Distribution (kg/m 2 ) Total and marketable yields were significantly influenced by treatment in both Fall 2010 and Spring 2011 (Table 2 6 and 2 7, respectively) In Fall 2010, total yields ranged from 0.96 to 4.49 kg/m 2 and marketable yields ranged from 0.88 to 4.01 kg/m 2 ( in both cases, these extremes were recorded from Soln Soln x NC and Convtl x YW treatment combinations, respectively). In Spring 2011, total yields ranged from 0.74 to 3.93 kg/m 2 (recorded in Soln Soln x N C and Convtl x YW treatment combinations, respectively) and marketable yields ranged from 0.29 to 2.91 kg/m 2 (recorded in Soln Soln x PL and Convtl x YW treatment combinations, respectively). Total and marketable bell pepper

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55 yields recorded in Fall 2010 we re relatively higher than the yields recorded in Spring 2011. In both years, the Soln Soln fertilizer treatment produced the lowest yields, in part due to the organic nutrient solution clogging the irrigation lines and emitters resulting in the plants rec eiving inadequate supply of nutrients and water (Rippy et al., 2004) While the Gran Soln and Soln Gran treatments also utilized organic nutrient solution fertigation, the solution was more dilute compared to the Soln Soln treatment because these treatment s involved granular nutrient sources incorporated into the media as well. Therefore the clogging issues from these treatments were not nearly as severe as those experienced in the Soln Soln treatme nt, resulting in better yields. Although other research and commer cial operations have claimed success with fertigating with organic spray dried fish protein fertilizers (Schwankl and McGourty, 1992) (which made up a large proportion of my organic nutrient solution mix), this study shows that these materials will still clog the irrigation system if its concentration in the stock solution is too high. The P in the hydrolyzed spray dried fish protein could have precipitated with the Ca in the calcium sulfate component of the organic nutrient solution, contributing to clogging issues as well. Fall 2010 Fertilizer x Compost interaction effect significantly influenced total yield ( P = 0.0014) (Figure 2 7) Within the Gran Gran, Soln Gran and Soln Soln fertilizer treatments, PL compost treatment produced higher total yiel d than NC and YW (by 1 and 17, 70 and 56, 163 and 108 % respectively) Within NC c ompost treatment, fertilizer treatment total yields followed the pattern Convtl > Gran Gran = Gran Soln > Soln Gran > Soln Soln Within YW compost treatment, Convtl fertilize r treatment achieved higher

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56 total yield than all others (by 92 271%) and Gran Gran produced greater total yield than Soln Soln (by 93%). Fertilizer main effect significantly influenced marketable yield ( P < 0.0001) (Table 2 6) Gran Gran, Gran Soln and So ln Gran treatments produced similar marketable yields that were significantly higher than that of Soln Soln but lower than that of t he Convtl treatment, producing 67, 63 and 54%, respectively, of the 3.47 kg/m 2 marketable yield achieved by Convtl This is in contrast to a greenhouse grown mature green, indeterminate (214 DAT) bell pepper experiment in which marketable yield of organic bell peppers grown in horse manure amended soil was not significantly different from yield of conventionally gr own bell p eppers (d el Amor, 2007 ). Although the interaction was not significant the Gran Gran, Gran Soln and Soln Gran fertilizer treatments combined with PL compost treatment produced the highest organic marketable yields of 2.34, 2.37 and 2.44 kg/m 2 respectively corresponding to 67 71 % of the Convtl x NC marketable yield of 3.49 kg/m 2 58 61% of the Convtl x YW marketable yield of 4.01 kg/m 2 and 80 84% of the Convtl x PL marketable yield of 2.92 kg/m 2 Some research suggests that only 50% of the total applied nitrogen in organic nutrient sources is made available in a given season As a result, organic production guidelines often suggest applying organic nitrogen at a rate two times that of conventional inorganic nitrogen However, this was not done in this stu dy because it was important to keep applied nutrient (especially nitrogen) levels consistent across treatments for comparison purposes (in both the production and economic analysis studies), and also because other research has shown higher disease incidenc e and leachate/substrate EC (and therefore lower marketable yields) from higher nitrogen

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57 (organic or inorganic) fertilizer rates ( Miles and Peet, 2002 ; Rippy et al, 2004 ; Zhai et al., 2009 ). It was also important to keep organic nutrient management input c osts down to help ensure positive partial net returns in the subsequent economic analysis. T he majority of non culled peppers fell within the XL, L and M size classes for the Convtl, Gran Gran, Gran Soln, and Soln Gran fertilizer treatments while the majo rity of non culled peppers fell within the M size class for the Soln Soln fertilizer treatment (Table 2 6) Fertilizer main effect significantly influenced yield of XL size peppers ( P < 0.0001) with means separation paralleling that of marketable yield. Fe rtilizer x Compost interaction effect significantly influenced yield of L and M size peppers ( P = 0.0092 and P = 0.0433, respectively) (Figure 2 8 and 2 9, respectively) Spring 201 1 Fertilizer main effect significantly influenced total and marketable yiel d ( P < 0.0001 and P = 0.0003, respectively ) (Table 2 7) Gran Gran, Gran Soln and Soln Gran treatments produced total yields that were significantly higher than that of Soln Soln, but lower than that of the Convtl treatment, producing 56, 63 and 46%, respe ctively, of the total yield of 3.55 kg/m 2 achieved by Convtl Gran Gran and Gran Soln treatments produced marketable yields that were significantly higher than that of Soln Soln and comparable to that of Convtl, producing 63 and 87%, respectively, of the m arketable yield of 2.21 kg/m 2 achieved by Convtl. Additionally, Gran Soln resulted in significantly higher total and m arketable yields than Soln Gran Although the interaction was not significant the Gran Gran x YW Gran Soln x NC and Gran Soln x PL treat ment combinations produced the highest organic marketab le yields of 1.65, 1.86 and 2.45 kg/m 2 resp ectively, corresponding to 93, 104 and 138 % of the Convtl x NC marketable

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58 yield of 1.78 kg/m 2 57, 64 and 84 % of the Conv tl x YW marketable yield of 2.91 kg/ m 2 and 85, 96 and 126 % of the Convtl x PL marketable yield of 1.94 kg/m 2 T he majority of non culled peppers fell within the XL, L and M size classes for Convtl, the L, M and S size classes for Gran Gran and Gran Soln, and the M and S size classes for So ln Gran and Soln Soln fertilizer treatments. Fertilizer main effect significantly influenced yield of XL L, and U size peppers ( P = 0.0137, 0.0044 and 0.0322, respectively ) (Table 2 7) The yield of XL size peppers from Gran Soln was comparable to that fr om Convtl and the yield of L size peppers from Gran Gran and Gran Soln was comparable to that from Convtl, with significantly lower yields of these size classes from the other fertilizer treatments. Fertilizer and Compost main effect s significantly influe nced yield of M size peppers ( P = 0.0007 and 0.0231 respectively ), with Soln Soln fertilizer and PL compost treatments yielding less M size peppers tha n all other fertilizer or compost treatments. Fertilizer x Compost interaction effect significa ntly infl uenced yield of S size peppers ( P = 0.0442) (Figure 2 10) The greenhouse utilized for this experiment was not hooked to a back up generator. Several times during the Spring 2011season, at crucial plant and fruit development stages, storms caused power out ages in the greenhouse, which caused the irrigation system to turn off. During these times, all plants did not receive water (and in some cases nutrients, depending on the treatment) for 1 2 days at a time in hot Florida s pring temperatures. This caused a reduction in yields compared to Fall 2010 yields This situation was compounded in the organic treatments because dry media conditions would have slowed down the mineralization rate, depriving the organic plants of much needed nitrogen during stages of hig h vegetative and reproductive growth

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59 (Sanchez and Richard, 2009). Also, the transplant date of 9 March is relatively late. Yields could very likely have been higher for the Spring 2011 trial if the seedlings were transplanted into the greenhouse in January or early February, so that harvest occurred before the high Florida temperatures could stress the plants and contribute to decreased fruit quality. Bell Pepper Quality (kg/m 2 ) Fall 2010 Fertilizer and Compost main effects significantly influenced yield of fruit with external defects (Table 2 8) The Convtl fertilizer treatment resulted in higher yields of total culls ( P = 0.0165) and blossom end rot peppers ( P = 0.0026) and both Convtl and Soln Gran treatments resulted in higher yields of flat shape peppe rs ( P = 0.0066) than all other fertilizer treatments. The PL compost treatment resulted in higher yields of total culls ( P = 0.0084) and sunscald peppers ( P = 0.0029) and PL resulted in higher and YW resulted in lower yields of blossom end rot peppers ( P = 0.0003) compared to the other compost treatments. Spring 2011 Fertilizer x Compost interaction effect significantly influenced yield of culls ( P = 0.0204) and blossom end rot peppers ( P = 0.0143) (Figure 2 11 and 2 12 respectively ) Within all five fert ilizer treatments, PL compost treatment resulted in higher yield of total culls and blossom end rot peppers than NC and YW. Within all three compost treatments, Convtl fertilizer treatment resulted in higher yield of total culls and blossom end rot peppers than all other fertilizer treatments. Within PL compost treatment only, Gran Soln resulted in lower yield of total culls than Gran Gran and lower yield of blossom end rot peppers than all other fertilizer treatments. Fertilizer main effects

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60 significantly influen ced yield of flat shape and mis shapen peppers (Table 2 9) The Convtl and Gran Gran treatments re sulted in higher yields of flat shape fruit ( P < 0.0001) and Soln Soln r esulted in higher yields of mis shapen fruit ( P = 0.0287) compared to all other f ertilizer treatments. Bell Pepper Fruit Counts and Percent Yields Bell pepper fruit counts and percent yields were significantly influenced by treatment in both Fall 2010 and Spring 2011. In Fall 201 0, total yields ranged from 10 to 35 fruit /m 2 and marketa ble yields ranged from 9 to 30 fruit /m 2 (in both cases, these extremes were recorded in Soln Soln x NC and Convtl x NC treatment combinations, respectively). Percent marketable yield by weight ranged from 77.2% in Soln Soln x PL to 95.7% in Gran Gran x YW. Total culls ranged from 0.6 fruit/m 2 and 1.8% in Gran Gran x YW to 7 fruit/m 2 and 17.9% in Convtl x PL. Blossom end rot ranged from 0 fruit/m 2 and 0% in all organic fertilizer treatmen ts paired with YW compost to 5 fruit/m 2 and 13.1% in Convtl x PL. In Sp ring 2011, total yields ranged from 17 to 85 fruit/m 2 (from Soln Soln x NC and Convtl x PL, respectively) and marketable yields ranged from 6 to 31 fruit/m 2 ( from Soln Soln x PL and Convtl x YW, respectively). Percent marketable yield by weight ranged fro m 21.7 % in Soln Soln x PL to 88.9% in Gran Soln x NC. Total culls ranged from 3 fruit/m 2 in Soln Soln x YW and 7.6% in Gran Soln x YW to 51 fruit/m 2 and 55.9% in Convtl x PL. Blossom end rot ranged from 0 fruit/m 2 and 0% in Soln Gran x YW, Soln Soln x YW a nd Soln Soln x NC to 46 fruit/m 2 and 49.2% in Convtl x PL. Fall 2010 Fertilizer x Compost interaction effect significantly influenced number of total and marketable fruit per square meter ( P < 0.0001 and P < 0.0001, respectively) (Figure 2

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61 13 and 2 14, res pectively) Within Convtl fertilizer treatment, PL compost treatment produced less marketable fruit than NC and YW. Within Gran Gran fertilizer treatment, PL compost treatment produced more total fruit than YW, and within Gran Soln fertilizer treatment NC compost treatment produced more total and marketable fruit than YW. Within Soln Gran and Soln Soln fertilizer treatments PL compost treatment produced more total and marketable fruit than NC and YW. Within NC and YW compost treatment s Convtl fertilizer produced significantly more total and marketable fruit than all other fertilizer treatments. Within NC compost treatment, Gran Gran and Gran Soln fertilizer treatments produced more total and marketable fruit than the other two organic fertilizer treatment s. Within YW compost treatment, Soln Soln produced less total and marketable fruit than the other three organic fertilizer treatments. Within PL compost treatment, number of total and marketable fruit is statistically similar among all fertilizer treatment s. Fertilizer main effect significantly influenced number of culled fruit and blossom end rot fruit per square meter and percent blossom end rot yield ( P = 0.0167, 0.0125 and 0.0195, respectively) (Table 2 10) Convtl fertilizer treatment resulted in high er number of culled and blossom end rot fruit than all other fertilizer treatments. While the percent blossom end rot yield was statistically similar across the four organic fertilizer treatments, Convtl fertilizer resulted in a higher percentage than Soln Gran and Soln Soln treatments. Compost main effect significantly influenced number of culled fruit and blossom end rot fruit per square meter and percent marketable, culled and blossom end rot yield ( P = <0.0001, 0.0002, 0.0218, 0.0074 and <0.0001, respec tively) (Table 2 10) PL compost treatment resulted in higher number of culled and blossom end rot fruit and

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62 percent blossom end rot yield compared to the other compost treatments, and lower percent marketable yield and higher percent culled yield compared to YW compost treatment. Spring 2011 Fertilizer x Compost interaction effect significantly influenced number of total and blossom end rot fruit per square meter and percent blossom end rot yield by weight ( P = 0.0004, 0.0050 and 0.0038, respectively) (Fig ure 2 15, 2 16 and 2 17, respectively) Within all fertilizer treatments except for Soln Gran, PL compost treatment resulted in higher total fruit count than NC and YW Within all three compost treatments, Convtl fertilizer resulted in higher total fruit c ount than all other fertilizer treatments. Within NC and YW compost treatment, Soln Soln resulted in significantly lower total fruit count Within all fertilizer treatments except for Gran Soln, PL compost treatment resulted in significantly more blossom e nd rot (both in count and percent by weight ) compared to NC and YW. Within NC and YW compost treatments, Convtl fertilizer resulted in more blossom end rot (both in count and percent by weight ) than the other fertilizer treatments, and within PL compost tr eatment, Gran Soln fertilizer resulted in less blossom end rot than the other fertilizer treatments. Fertilizer main effect significantly influenced marketable and culled fruit count and percent yield by weight ( P = <0.0001, <0.0001, 0.0004 and <0.0001, r espectively) (Table 2 11) Convtl, Gran Gran and Gran Soln produced more marketable fruit and Gran Soln produced higher percent marketable yield compared to the other fertilizer treatments. The culled fruit count results of Convtl > Gran Gran > Soln Gran = Soln Soln > Gran Soln is generally reflected in percent culled yield with Convtl producing significantly higher percentage and Gran Soln lower percentage compared to the other

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63 fertilizer treatments. Compost main effect also significantly influenced these four variables ( P = 0.0272, <0.0001, <0.0001 and <0.0001, respectively) (Table 2 11) YW produced higher marketable fruit count than PL, both YW and NC produced higher percent marketable yield than PL, and PL produced higher culled fruit count and culled p ercent yield than YW and NC. Although, in general, plants in Spring 2011 produced more fruit per square meter than plants in Fall 2010, most of this fruit was unmarketable because of blossom end rot. The water stress that the Spring 2011 plants experienced due to the storm surges that turned off the irrigation system resulted in the physiological d isorder called blossom end rot (Bar Tal et al., 1999 ). Also, due to the high temperatures in Spring 2011, most of the water w as most likely drawn up into the matu re leaves to maintain functional transpiration rate, resulting in a lack of calcium reaching the actively growing cells of the young fruits (Marcelis and Ho, 1999) This calcium deficiency in the fruit led to blossom end rot. Of the fertilizer treatments, Convtl resulted in the most blossom end rot, partly because all of its nutrients were being fertigated through the irrigation system, so when the irrigation shut off, the plants were not receiving nutrients either, which may have caused a calcium deficienc y that led to blossom end rot as well. The high incidence of blossom end rot from the PL compost treatment may have been due to the relatively high phosphorus content in the poultry litter compost, which could have potentially limited calcium availability through precipitation reactions. However, the advantageous properties of the PL compost trea tment such as the low C:N ratio, high water holding capacity and temperature buffering capacity offset this disadvantage enough to still

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64 result in higher marketable yields of the organic fertilizer x PL compost treatment combinations compared to other organic treatments Plant Height and Leaf SPAD values Fall 2010 Plant height generally reflects yield results. Compost main effect significantly influenced plant heigh t at 17 DAT ( P = 0.0041) (Table 2 12) Plants grown with PL compost treatment were taller than plants grown with NC or YW. At 40 DAT, Fertilizer x Compost interaction effect significantly influenced plant height ( P = 0.0029) (Figure 2 18) Within Gran Gran fertilizer treatment, PL produced taller plants than YW; within Soln Gran fertilizer treatment, PL produced taller plants than YW which produced taller plants than NC; and within Soln Soln fertilizer treatment, PL produced taller plants than both YW and N C. Within NC compost treatment, Convtl and Gran Gran produced taller plants than Soln Gran and Soln Soln; within YW compost treatment, Convtl produced taller plants than all other fertilizer treatments; and within PL compost treatment, Gran Soln produced s horter plants than all other fertilizer treatments. Fertilizer main effect significantly influenced relative leaf SPAD values at all four sampling dates ( P = 0.0155, 0.0002, <0.000 1 and <0.0001, respectively) (Table 2 12) G ran Soln resulted in lower leaf SPAD values at 17 DAT and Convtl resulted in higher leaf SPAD values at 40, 60 and 86 DAT compared to all other fertilizer treatments. At 60 DAT, leaf SPAD values were higher from the Gran Gran compared to the Gran Soln fertilizer treatment. At 60 and 86 D AT, the Soln Gran fertilizer treatment produced higher leaf SPAD values than the Gran Soln and Soln Soln fertilizer treatments. Compost main effect significantly influenced relative leaf SPAD values at 17 and 40

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65 DAT ( P = 0.0027 and <0.0001, respectively) ( Table 2 12) At both sampling dates YW produced lower leaf SPAD value than NC or PL. Spring 2011 Plant height generally reflects yield results. Fertilizer and Compost main effects significantly influenced plant height at 21 DAT ( P = 0.0059 and 0.0015, res pectively) (Table 2 13) Convtl produced taller plants than all other fertilizer treatments, and PL produced taller plants than all other compost treatments. At 44 DAT, Fertilizer x Compost interaction effect significantly influenced plant height ( P = 0.02 67) (Figure 2 19) Within Gran Soln and Soln Gran fertilizer treatments, PL produced taller plants than NC or YW compost treatments. Within NC and YW compost treatment s Convtl, Gran Gran and Gran Soln produced similar size plants that were taller than tho se produced by the other fertilizer treatments; and within PL compost treatment, Convtl and Gran Soln produced plants of comparable size that were taller than those produced by the other fertilizer treatments. Fertilizer and Compost main effects also signi ficantly influenced plant height at 56 and 89 DAT (Table 2 13) At 56 DAT, Convtl and Gran Soln produced similar size plants that, along with those produced by Gran Gran, were taller than those produced by Soln Gran and Soln Soln ( P <0.0001). At 89 DAT, C onvtl produced taller plants than all other fertilizer treatments and Gran Soln produced taller plants than Soln Gran and Soln Soln ( P <0.0001). At both 56 and 89 DAT, YW and PL compost treatments produced taller plants than NC ( P = 0.0017 and 0.0002 resp ectively ). Fertilizer x Compost interaction effect significantly influenced relative leaf SPAD values at 21 DAT ( P = 0.0061) (Figure 2 20) Within Convtl fertilizer treatment, PL compost treatment resulted in higher leaf SPAD values than NC; within Gran So ln

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66 fertilizer treatment, NC compost treatment resulted in higher leaf SPAD values than PL; and within Soln Gran fertilizer treatment, both NC and PL compost treatments produced higher leaf SPAD values than YW. Within NC compost treatment, Convtl fertilizer produced higher leaf SPAD values than Soln Gran; within YW compost treatment, Convtl and Gran Gran fertilizers produced comparable leaf SPAD values that were higher than those produced by the other fertilizer treatments; and within PL compost treatment, C onvtl fertilizer resulted in higher leaf SPAD values and Gran Soln resulted in lower leaf SPAD vales compared to the other fertilizer treatments. At 44, 56 and 89 DAT, Fertilizer main effect significantly influenced leaf SPAD values ( P = 0.0009, <0.0001 an d <0.0001, respectively) (Table 2 13) At 44 DAT, Convtl fertilizer produced higher leaf SPAD values than all other fertilizer treatments. At 56 DAT, Convtl and Soln Gran produced comparably higher leaf SPAD vales and Gran Soln produced lower leaf SPAD val ues than the other fertilizer treatments. At 89 DAT, Convtl and Soln Soln produced the comparably highest leaf SPAD values and Gran Gran and Gran Soln produced the comparably lowest. At 44, 56 and 89 DAT, Compost main effects also significantly influenced leaf SPAD values ( P = <0.0001, 0.0382 and 0.0241, respectively) (Table 2 13) At 44 DAT, PL compost treatment produced higher leaf SPAD values than NC, which produced higher leaf SPAD values than YW. At 56 DAT, NC compost treatment produced leaf SPAD value s that were comparable to those of PL and higher than those of YW. At 89 DAT, NC compost treatment produced leaf SPAD values that were comparable to those of YW and higher than those of PL. Leachate pH, EC and Nitrate Concentration For hydroponic greenhous e bell pepper, optimum leachate pH is between 5.5 and 7.0 pH (the range in which macronutrients are most readily available for plant uptake)

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67 (Rippy et al., 2004) and optimum leachate EC is between 1.5 and 2.5 mS/cm. In both Fall 2010 and Spring 2011, the f irst leachate sampling date occurred the day before sidedress fertilizers were applied. Fall 2010 There were no significant F ertilizer main effects for leachate pH at 29 DAT (ranging from pH 6.7 to pH 7.3) however Fertilizer main effect did significantly influence leachate pH at 59 and 92 DAT ( P = <0.0001 and <0.0001, respectively) and leachate EC at 29, 59 and 92 DAT ( P = 0.0025, <0.0001 and <0.0001, respectively) (Table 2 14) At both 59 and 92 DAT, the leachate pH was lower ( pH 6.5 and pH 6.4, respectiv ely) and, at all three sampling dates, leachate EC was higher (1.9, 2.9 and 3.7 mS/cm, respectively) from the Convtl treatment than from all other fertilizer treatments. The Convtl fertilizer treatment includes phosphoric acid which lowers the pH; however, the organic fertilizer treatments do not have a component that is as acidic, which explains their higher leachate pH similar to re sults reported by Rippy et al. ( 2004 ) The higher leachate EC of the Convtl treatment is due to the fact that its components are salt based whereas the organic fertilizers are slowly mineralized into salts throughout the season. At 59 DAT, the leachate pH was lower and leachate EC was higher from the Soln Gran treatment ( pH 7.0 and 1 .7 mS/cm, respectively) than from the Gran G ran treatment ( pH 7.3 and 0.9 mS/c m respectively). At 92 DAT, the leachate pH w as higher from the Gran Soln treatment ( pH 7.3) and leachate EC was higher from the Gran Gran and Soln Gran treatments (2.5 and 2.6 mS/cm, respectively) than from all other fer tilizer treatments. The pH and EC levels were acceptable throughout the season for the Convtl fertilizer treatment (although EC was a little high at the end of the season). However, pH was either at the high end of acceptable range or slightly higher for t he

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68 organic treatments; and EC was lower than acceptable range for all the organic treatments throughout the season accept for Soln Gran at 59 DAT (1.7 mS/cm) and Gran Gran and Soln Gran at 92 DAT (2.5 and 2.6 mS/cm, respectively). The acceptable EC at the end of the season for these two organic treatments perhaps was due to their granular fertilizer sidedress and could have contributed to their higher yields compared to the other organic fertilizer treatments However, the relatively higher than optimal pH and lower than optimal EC of the organic fertilizer treatments most likely contributed to their lower yie lds compared to the Co n v tl treatment. A t all three sampling dates, Compost main effect significantly influenced leachate pH and EC ( P <0.0001 in all c ases) (Table 2 14) At 29 DAT, leachate pH followed the pattern NC < PL < YW ( pH 6.5, pH 7.1 and pH 7.5, respectively), and leachate EC followed the pattern PL > YW > NC (2.1, 1.0 and 0.6 mS/cm, respectively). At 59 DAT, leachate pH was lower from the NC c ompost treatment ( pH 6.6) than fro m PL or YW ( pH 7.1 and pH 7.3, respectively) and leachate EC was hi gher from the PL compost treatment (2.4 mS/cm) than fr om YW or NC (1.4 and 1.0 mS/cm, respectively). At 92 DAT, leachate pH followed the same pattern as it did at 29 DAT NC < PL < YW ( pH 6.5, pH 7.1 and pH 7.3 respectively), and leachate EC followed the same p attern as it did at 59 DAT PL > YW = NC (3.4, 1.6 and 1.5 mS/cm, respectively). In general, NC compost treatment displayed lowest leachate pH and wi thin optimal range, while YW and PL displayed leachate pH higher than optimal range, with YW having higher pH than PL. These results reflect the pH levels of the compost media mixes presented in Table 2 5. Because the organic fertilizer treatments already result in relatively high leachate pH, pairing them with the PL compost treatment is a better

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69 option than the YW because of its relatively lower pH, resulting in greater yields. Although the NC compost trea tment results in the best leachate pH levels, the low yields from its pairing with the organic fertilizer treatments is most likely due to the lack of compost in the NC media mix and its high C:N ratio which results in a media environment that is not optimal for mineralizing and nitrifying microorganisms The lack of compost in the NC treatment also results in low leachate EC, making it a n unfavorable media for the already low EC organic fertilizer treatments On the other hand, because of the higher soluble salt, sodium, potassium and other nutrient cont ent in the poultry litter compost, the PL compost treatment results in higher leachate EC than the YW or NC treatments and so can help to offset the low EC from the organic fertilizers, resulting in favorable yields from the organic fertilizer x PL compost pairing. In the study conducted by Rippy et al. ( 2004 ), the organic treatments experienced much higher than optimal leachate EC early in the season because the organic media was amended with large amounts of organic composts and fertilizers all at once at transplanting. This situation leads to salt toxicity in the young plants and can negatively affect yields; this situation w as avoided in my study by using lower amounts of amendments and splitting them into two applications. A t all three sampling dates, F ertilizer main effect significantly influenced leachate NO 3 N concentration ( P <0.0001 in all cases) (Table 2 14) At all three sampling dates, leachate [NO 3 N] was higher from Convtl than from al l other fertilizer treatments due to the soluble mineral bas ed calcium nitrate fertilizer ingredient in the Convtl treatment At 92 DAT, Soln Gran produced higher leachate [NO 3 N] than Gran Soln or Soln Soln fertilizer treatments, and Gran Gran produced higher leachate [NO 3 N] than Soln Soln

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70 fertilizer treatment p erhaps due to the organic granular fertilizer sidedress in the Soln Gran and Gran Gran treatments At 29 and 92 DAT, Compost main effect significantly influenced leachate NO 3 N concentration ( P = 0.0163 and 0.0004, respectively) (Table 2 14) At both sampl ing dates, PL produced higher leachate [NO 3 N] than NC or YW compost treatments. The poultry litter compost had the lowest C:N ratio (Table 2 4) allowing the microorganisms to mineralize organic nitrogen into plant available forms at a faster rate compared to the yard waste compost, peat and pine bark, resulting in higher leachate [NO 3 N] from the PL compost treatment compared to NC and YW (Sanchez and Richard, 2009) This could also explain why the organic fertilizers x PL compost treatment produced the hi ghest organic yields. Because the NC treatment had no compost, it could have had less nitrifying microorganisms, and its high C:N ratio could have contributed to a slower rate of nitrification, resulting in the lower yields produced form the organic fertil izers x NC treatment combinations ( Chang et al., 2007; Sanchez and Richard, 2009; Zhai et al., 2009 ). In general, leachate from PL compost treatment had lower (more optimal) pH compared to YW, higher (more optimal) EC compared to NC and YW, and higher (mo re optimal) [NO 3 N] compared to NC and YW. This explains why the organic fertilizer treatments paired with PL compost treatment achieved higher fruit yields compared to other organic treatment combinations. In general, leachate from the all granular (Gran Gran) and combinations of granular and solution (Gran Soln and Soln Gran) organic fertilizer treatments resulted in higher (more optimal) EC by end of season and the higher [NO 3 N] throughout the season, compared to the all organic solution ( Soln Soln) tre atment. This could be partly explained by the clogging problems experienced in the

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71 Soln Soln treatment. As a result, Gran Gran, Gran Soln and Soln Gran fertilizer treatments achieved higher fruit yields compared to Soln Soln, especially when paired with PL compost treatment. Although conventional hydroponic fertilizer systems are not often paired with a media amended with compost, the Convtl fertilizer treatment paired with YW compost treatment achieved the highest yields. The high pH and low EC of the leac hate from the Y W treatment is offset by the Co n v tl fertilizer, so the Convtl x YW treatment combination coul d have benefited from the media enhancing properties of yard waste compost such as the higher water holding capacity temperature buffering capacity etc. resulti ng in higher yields from the Convtl x YW treatment combination compared to Convtl x NC control. Spring 2011 Fertilizer x Compost interaction effect significantly influenced leachate EC at 30 DAT ( P = 0.0017) (Figure 2 21) Within all fertili zer treatments except for Gran Soln, PL compost treatment produced significantly higher leachate EC (ranging from 3.6 to 4.0 mS/cm which is higher than optimal EC ) than NC or YW, and YW compost treatment produced higher leachate EC than NC treatment. In m ost cases, any fertilizer treatment paired with NC or YW resulted in below optimal EC. Within NC compost treatment, Convtl, Gran Gran and Gran Soln fertilizer treatments resulted in higher leachate EC than the othe r treatments, however all were below optim al EC range. Within YW compost treatment, Gran Gran produced higher leachate EC (2.2 mS/cm, within optimal EC range) than all other fertilizer treatments (which showed EC levels below optimal range). Within PL compost treatment, there were no significant d ifferences among fertilizer treatments, and all exhibited higher than optimal leachate EC except for Gran Soln.

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72 T here were no significant Fertilizer main effects for leachate pH at 30 and 52 DAT (ranging from pH 6.4 to pH 6.7), however Fertilizer main effe ct did significantly influence leachate pH at 73 DAT ( P = 0.0065) and leachate EC at 52 and 73 DAT ( P < 0.0001 on both dates) (Table 2 15) At 52 DAT, leachate EC from Gran Gran fertilizer treatment (3.3 mS/cm) was comparable to that of Soln Gran (2.4 mS/c m) and higher than EC from the other fertilizer treatments potentially due to the organic granular fertilizer sidedress applied in both these treatments Leachate EC from Soln Gran was comparable to that of Convtl (2.2 mS/cm), both of which were higher th an EC from Gran Soln fertilizer treatment (1.0 mS/cm). At 73 DAT, leachate pH was lower from Convtl ( pH 6.1) than from all other fertilizer treatments reflecting Fall 2010 results Leachate EC from Gran Gran (2.5 mS/cm) was comparable to that of Convtl (3 .3 mS/cm) and Soln Gran (2.1 mS/cm), all of which were higher than EC from Gran Soln and Soln Soln reflecting Fall 2010 results Compost main effect significantly influenced leachate pH at all three sampling dates ( P = 0.0214, 0.0010 and 0.0004, respectiv ely) and leachate EC at 52 and 73 DAT ( P <0.0001 on both dates) (Table 2 15) At all three sampling dates, leachate pH from YW and PL compost treatments were comparable (ranging from pH 6.6 to pH 6.7) and higher than leachate pH from NC similar to Fall 20 10 results At 52 and 73 DAT, leachate EC was higher from PL compost treatment (3.3 and 3.4 mS/cm, respectively) than from NC or YW reflecting Fall 2010 results Across treatments, the leachate pH levels were lower in Spring 2011 compared to Fall 2010 and all within optimum range. However, on average, the leachate EC levels were higher, especially from treatments paired with Convtl fertilizer or PL compost. The

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73 Convtl fertilizer treatment utilizes all salt based nutrients and the poultry litter compost has substantially higher soluble salt, sodium and potassium content. When the irrigation system shut off due to storm surges, the lack of water could have caused the salts to build up in the media of plants under the Convtl fertilizer treatment or PL compost treatment. This extra salinity stress could have compounded the water stress, resulting in the higher incidence of blossom end rot from these treatments compared to all others. Fertilizer main effect significantly influenced leachate NO 3 N concentration at all three sampling dates ( P = 0.0242, <0.0001 and <0.0001, respectively) (Table 2 15) At 30 DAT, Convtl showed higher leachate [NO 3 N] than all other fertilizer treatments except for Soln Gran. At 52 DAT, Convtl, Gran Gran and Soln Gran resulted in compa rable leachate [NO 3 N] that was higher than those from the other two organic fertilizer treatments. At 73 DAT, Convtl produced higher leachate [NO 3 N] than all other fertilizer treatments, and Gran Gran and Soln Gran produced higher leachate [NO 3 N] than t he other two organic fertilizer treatments. Compost main effect significantly influenced leachate NO 3 N concentration at all three sampling dates ( P = <0.0001, 0.0003 and 0.0131, respectively) (Table 2 15) On all sampling dates, PL produced significantly higher leachate [NO 3 N] than NC or YW compost treatments. All these results reflect those in Fall 2010. Plant Biomass and Nutrient Content at Harvest Fall 2010 Fertilizer x Compost interaction effect significantly influenced whole plant dry weight at harve st ( P =0.0048) (Figure 2 22) reflecting yield results Within Gran Gran fertilizer treatment, PL compost treatment produced greater plant biomass than YW; within Gran Soln fertilizer treatment, PL and NC compost treatments produced greater

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74 plant biomass th an YW; and within Soln Gran and Soln Soln fertilizer treatments, PL compost treatment produced greater plant biomass than NC and YW. Within NC compost treatment, plant biomass followed the patter Convtl > Gran Gran = Gran Soln > Soln Gran > Soln Soln. With in YW and PL compost treatments, Convtl produced significantly greater plant biomass than a ll other fertilizer treatments Fertilizer and Compost main effect significantly influenced leaf percent TKN at harvest ( P = <0.0001 and 0.0031, respectively) (Table 2 16) Convtl fertilizer treatment produced higher leaf percent TKN than all other treatments, and Soln Gran and Soln Soln produced higher leaf percent TKN than the other two organic fertilizer treatments. NC compost treatment produced higher leaf percent TKN than YW or PL. These results agree with a greenhouse grown bell pepper experiment by d el Amor ( 2007 ) in which leaf [NO 3 N] was lower and shoot and leaf fresh weight were reduced by 32.6 and 35%, respec tively, in the organic treatments compared to the conventional treatment. The leachate [NO 3 N] results in my study indicate that a smaller percentage of plant available nitrogen is present at any given time in the organic treatments, compared to conventional, due to the fact that organic nitrogen must be mineralized into plant available forms by microbes. This would result in lower leaf percent TKN and slower leaf expansion and plant growth rate and, therefore, the lower whole plant dry weight from the organic treatments at the end of the season (d el Amor 2007 ; Martinez et al., 2005 ; Van Delden, 2001). However, nitrogen pools in the stems could have acted to regulate and maintain fruit yield at the expense of vegetative growth (d el Amor, 2007 ). On the other hand, these resu lts are in contrast to the studi es by Rippy et al. (2004) and Zhai et al. (2009) in which greenhouse grown tomato leaf nitrogen content at

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75 mid season and 132 DAT, respectively, was comparable among organic and conventional systems. Spring 2011 Fertilizer and Compost main effect s signific antly influenced whole plant dry weight at harvest ( P < 0.0001 for both effects) (Table 2 17), reflecting yield results Convtl fertilizer treatment produced greater plant biomass than all other treatments, and Gran Gran and Gran Soln produced greater plan t biomass than the other two organic fertilizer treatments. PL compost treatment produced greater plant biomass than NC or YW. Across all treatments, whole plant dry weight was almost twice that of plants from the Fall 2010 trial, indicating that while the plants might have been healthier, it did not translate into higher yields due to the blossom end rot problems and perhaps more nutrients were being allocated to vegetative growth as opposed to reproductive growth indicating the ratio of available nitroge n to potassium was not optimal for bell pepper yield Fertilizer main effect significantly influenced leaf percent TKN at harvest ( P < 0.0001) (Table 2 17) Convtl fertilizer treatment produced higher leaf percent TKN than all other treatments Soln Soln pr oduced higher leaf percent TKN than Soln Gran and both produced higher leaf percent TKN than the other two organic fertilizer treatments reflecting Fall 2010 results Fruit Characteristics and Nutrient Content/Efficiency at Harvest Fall 2010 Fertilizer ma in effect significantly influenced fruit p ericarp thickness, fresh weight, dry weight and percent NUE at harvest ( P < 0.0001 in all cases) (Table 2 16) reflecting yield and quality results Convtl fertilizer treatment produced thicker pericarps than all

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76 o ther fertilizer treatments, and Gran Gran and Soln Gran produced thicker pericarp s than Soln Soln Thicker pericarps are desirable because they may be less susceptible to cracking during handling and they may create heavier fruit, requiring less fruit to f ill a 5 kg carton (S haw and Cantliffe 2002). Fruit from Gran Gran fertilizer treatment had fresh weight comparable to fruit from Convtl, and fruit from Gran Gran, Gran Soln and Soln Gran had fresh weight comparable to one another and higher than fruit fre sh weight from Soln Soln fertilizer treatment. Convtl, Gran Gran, and Soln Gran produced similar fruit dry weights that were greater than that of Gran Soln fertilizer treatment, and all fertilizer treatments produced fruit dry weights greater than Soln Sol n. Convtl fertilizer treatment resulted in higher fruit percent NUE than all other treatments, and Gran Gran, Gran Soln and Soln Gran resulted in higher fruit percent NUE than Soln Soln. Compost main effect significantly influenced fruit lobe number and pe rcent NUE at harvest ( P = 0.0208 and 0.0028, respectively) (Table 2 16), reflecting yield and quality results PL compost treatment produced fruit with higher lobe number than NC, and resulted in higher fruit percent NUE than NC and YW compost treatments. Fertilizer x Compost interaction effect significantly influenced fruit percent TKN at harvest ( P = 0.0001) (Figure 2 23), reflecting yield and quality results Within Convtl fertilizer treatment, PL compost treatment produced higher fruit percent TKN than NC or YW; within Gran Gran fertilizer treatment, YW compost treatment produced higher fruit percent TKN than PL; within Soln Gran fertilizer treatment, NC produced higher fruit percent TKN than YW or PL. Within NC compost treatment, Convtl and Soln Gran p roduced similar fruit percent TKN that as higher than that of all other fertilizer

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77 treatments. Within YW and PL compost treatments, Convtl produced higher fruit percent TKN than all other fertilizer treatments. Spring 2011 Fertilizer main effect significan tly influenced fruit pericarp thickness fresh weight, percent TKN and percent NUE ( P = 0.0191, 0.0001, <0.0001 and <0.0001, respectively) (Table 2 17), generally reflecting yield and quality results Convtl, Gran Gran and Gran Soln fertilizer treatments p roduced fruit with comparable pericarp thickness, and Convtl and Gran Soln produced thicker pericarps than Soln Soln. Convtl and Gran Soln produced fruit with comparable fresh weights that were greater than that of fruit produced by the other fertilizer tr eatments. Convtl produced higher fruit percent TKN and percent NUE than all other fertilizer treatments, and Soln Gran and Soln Soln produced higher fruit percent TKN than Gran Gran and Gran Soln. Across all treatments, fruit pericarp thickness, fresh weig ht and dry weight was lower than that of fruit from Fall 2010, reflecting yield and quality results. Fertilizer x Compost interaction effect significantly influenced fruit lobe number ( P = 0.0227) (Figure 2 24) Within Gran Soln and Soln Gran fertilizer t reatments, PL compost treatment produced fruit with more lobes than NC; and within Soln Soln fertilizer treatment, both PL and YW compost treatments produced fruit with more lobes than NC. Within NC compost treatment, Convtl and Gran Gran fertilizer treatm ents produced fruit with more lobes than Soln Gran and Soln Soln; and within YW compost treatment, Convtl and Gran Gran fertilizer treatments produced fruit with more lobes than Soln Gran.

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78 Conclusions Peat and pine bark substrate amended with poultry litte r compost and fertilized with all granular or either combination of organic granular and nutrient solution sources produced the highest organic greenhouse marketable red bell pepper yields of 57 138% of the hydroponic control. Because different organic nut rient fertilizers and media/composts vary considerably in their properties and rates of nutrient availability, using multiple sources of organic nutrients and a combination of incorporated, top dressed and fertigated fertilization systems may increase the size, biodiversity and activity of the microbial populations in the media, thereby influencing the physical, chemical and biological characteristics of the media that govern plant health as well as nitrification/mineralization activities and, therefore, yi eld ( Chang et al., 2007, Greer and Diver, 2000 ; Treadwell et al., 2007; Zhai et al., 2009). In my study, organic granular fertilizer treatments consisted of four different products and organic solution fertilizer treatments consisted of three different pr oducts for a total of seven different organic nutrient sources applied to the Gran Soln or Soln Gran fertilizer treatments. S ince organic fertilizers delivered hy d roponically tend to clog the irrigation system, it may be best to not use them at all (Gran Gran treatment) or delay their use for the first 30 days and then fertigate with them at low concentration (Gran Soln treatment). Incorporating half of total season nutrients via granular organic fertilizers into the media at transplant avoids excessive EC and allows the plants to derive their nutrients from granular sources until 30 days after t ransplant, at which time the rest of total season nutrients can be supplied by an organic granular sidedress or a dilute organic nutrient solution delivered through the irrigation system regularly until harvest.

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79 Poultry litter compost is more effective than yard waste compost for organic greenhouse bell pepper production b ecause it has lower pH, higher EC, more temperature buffering capacity, higher water holding cap acity, lower C:N ratio higher micronutrient concentrations and possibly more active nitrifying/mineralizing microorganism populations as evidenced by the higher leachate [NO 3 N] and fruit percent NUE. As a result, the media treatment containing poultry li tter compost ( PL ) resulted in higher yields, taller plant s throughout the season and greater whole plant dry weight at harvest compared to the media treatments containing no compost or yard waste compost However, it is important to keep water availability consistent because the high sodium, potassium and soluble salt levels in poultry litter compost can lead to higher than optimal EC and salt salinity stress under water deficiency, resulting in higher blossom end rot incidence and lower yields. Also, the p hosphorus content in poultry litter compost could potentially limit Ca availability through precipitation reactions, leading to blossom end rot, so effective calcium supplementation via fertilizers must be utilized to avoid this problem. On the other hand, because the poultry litter compost increased the water holding capacity of the media to 90%, it is important to not over irrigate, reducing the oxygen filled pore spaces that are necessary for nitrification reactions (Evanylo and McGuinn, 2009). For futur e research, it would also be interesting to apply this experiment to an indeterminate bell pepper cultivar, which is typically used in greenhouse production systems and has a crop season of 10 months. Although the organic nutrient solution in low concentra tion did fairly well, there were still clogging problems, and so a future study could look at exploring a variety of different organic nutrient sources to make into

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80 fertigation solution and assess their clogging potential. Also, future research could attem pt to acidify the organic nutrient solution with citric acid or other OMRI approved acidifying agent to help solubilize the materials and decrease the pH in the media of the organic treatments. It is important to note that during the course of this study, treatments, types and amounts of nutrient inputs, irrigation management and cultural practices were fixed for the sake of scientific and statistical repetition, consistency and more closely relate results to real world situations in which a grower would adjust all these factors throughout the season and from season to season to explore different approaches, remediate problems and maximize yield.

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81 Figure 2 1. The experiment si te: a multi bay, passively ventilated, saw tooth style greenhouse located at the University of in Marion County near Citra, Florida ( Source: http: // www.hos.ufl.edu/protectedag Last accessed 1 July 2012 ) A B Figure 2 2. The experime nt site: inside the greenhouse. A) The experiment was established in one bay of the greenhouse, where PVC pipes were placed in four rows (1.2 m apart) down the north south length of the greenhouse to serve as a drainage system. B) The fate of leachate on t he north end of the greenhouse and a close up view of the 50 mesh screen covering the side wall.

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82 A B Figure 2 3. Experiment set up. A) Determinate red b ell pepper seedlings were transplanted into 11.4 L polyethylene nursery pots and B) placed on the four rows of PVC pipe, representing the four blocks of the experiment, at a density of three plants/m 2

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83 Table 2 1 Nutrient sources used to make custom fertilizer mixes Convtl, Gran and Soln the determinate red bell pepper study in a saw tooth style greenhouse at UF PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Fertilizer Manufacturer Ingredients Percent of element z Convtl Calcium nitrate Chemical Dynamics, FL Ca(NO 3 ) 2 9 N, 11 Ca DynaPhos phosphoric acid Chemica l Dynamics, FL H 3 PO 4 23 P Potassium chloride Chemical Dynamics, FL KCl 51.5 K Epsom magnesium sulfate Giles Chemical, NC MgSO 4 9.8 Mg, 12.9 S Sequestrene c helated iron Southern Ag, FL FE 330 9 Fe Copper sulfate Southern Ag FL CuSO 4 25.2 Cu Manganese sulfate Southern Ag FL MnSO 4 29 Mn Zinc sulfate Hi Yield FL ZnSO 4 36 Zn Solubor boron Southern States, FL B 20.5 B Sodium molibdate Southern Ag FL Na 2 (Mo O 4 ) 39 Mo Gran Ag Life 2 4 2 OC Rhizogen, TX Composted poultry manure (granular) 2 N, 1 .8 P, 1.7 K, 5 Ca, 1 Mg, 0.8 S, 0.6 Fe, 0.1 Mn, 0.1 Zn Blending Base Fertilizer 13 0 0 Nature Safe, KY Hydrolyzed feather meal, meat meal and blood meal (pelleted) 13 N, 2 Ca, 1.3 S Allganic p otassium sulfate 0 0 51 SQM, GA K 2 SO 4 (granular) 42.3 K, 0.1 Ca, 0.2 Mg, 17 S Cal CM Plus calcium sulfate MP Art Wilson Co, NV Anhydrite CaSO 4 (granular) 23.3 Ca, 18.6 S Soln HFPC spr ay dried hydrolyzed fish protein California Spra y Dry Co, CA Fresh fish or fish frames from filleting plants (fine powder) 10.7 N,1.6 P, 1.1 K, 2.1 Ca, 0.1 Mg, 0.8 S, 0.1 Fe, Allganic p otassium sulfate 0 0 52 SQM, GA K 2 SO 4 (crystalline, water soluble) 43.2 K, 0.1 Ca, 0.2 Mg, 18 S Cal CM Plus calcium sulfate SG Art Wilson Co, NV Anhydrite CaSO 4 (solution grad e) 23.3 Ca, 18.6 S z N: nitrogen; Ca: calcium; P: phosphorus; K: potassium; Mg: magnesium; S: sulfur; Fe: iron, Cu: copper; Mn: manganese; Zn: zinc; B: boron; Mo: molibdate.

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84 Table 2 2 Target concentrations (mg/L) of nutrients in the Convtl fertilizer solution delivered through the irrigation system to determinate red bell pepper plants in a saw tooth style greenhouse at UF PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Nutrient Transplant to establishment Vegetative growth Vegetat ive growth to fruit set Fruit growth to mature green Fruit growth to mature red Nitrogen 80 120 140 150 160 Phosphorus 50 50 50 50 50 Potassium 119 148 173 202 215 Calcium 127 135 159 171 182 Magnesium 40 48 48 48 48 Sulfur 56 66 66 66 6 6 Iron 2.8 2.8 2.8 2.8 2.8 Copper 0.2 0.2 0.2 0.2 0.2 Manganese 0.8 0.8 0.8 0.8 0.8 Zinc 0.3 0.3 0.3 0.3 0.3 Boron 0.7 0.7 0.7 0.7 0.7 Molibdate 0.06 0.06 0.06 0.06 0.06 Table 2 3 Explanation of organic fertilizer treatments applied to determinat e red bell pepper plants in a saw tooth style greenhouse at UF PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Fertilizer Treatment Fertilizer Application Rates z Gran Gran Gran Incorporated into pots at transplant 50% of total season N P, K and Ca Gran Incorporated into pots at sidedress 50% of total season N, P, K and Ca Gran Soln Gran Incorporated into pots at transplant 50% of total season N and K ; 78% of total season P ; 69% of total season Ca Soln Deliv ered through irrigation system at low concentration f rom sidedress to harvest 50% of total season N and K ; 22% of total season P; 31 % of total season Ca Soln Gran Soln Delivered through irrigation sy stem at full concentration from transpla nt to sidedress and at low concentratio n from sidedress to harvest 50% of total season N and K ; 22% of total season P ; 31% of total season Ca Gran Incorporated into pots at sidedress 50% of total season N and K ; 78% of total season P ; 69 % of total season Ca Soln Soln Delivered throug h irrigation sy stem at full concentration from transplant to harvest Nutrient schedule matching that of Convtl z N: nitrogen; P: phosphorus; K: potassium; Ca: calcium.

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85 Figure 2 4. Irrigatio n design and equipment for delivery of water and nutrients to determinate red bell pepper plants in the saw PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Figure 2 5. Details of individual micro irrigatio n units. E ach determinate red bell pepper plant received water (and, in some treatments, nutrients) through a 7.6 L/h pressur e compensated emitter on the end of a 60 cm long spaghetti tube

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86 Table 2 4 Relevant physical and chemical properties of media com ponents in the determinate red bell pepper study in the saw tooth style greenhouse at UF PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Property Peat Pine bark Yard waste compost Poultry litter compost Soluble salts ( mmhos /cm) 0.21 0.07 0.40 11.67 Organic matter (% ) 57.72 56.70 22.88 11.63 C arbon :n itrogen ratio 64:1 121:1 25:1 7:1 pH 6.33 5.14 --Total n itrogen (mg/kg ) 12.61 7.35 3,200 10,000 Nitrate n itrogen ( mg/kg ) 6.30 2.80 100 700 Phosphorus ( mg/kg ) 0.79 2.03 528 9,284 Potassium ( mg/kg ) 7.91 12.86 1,494 11,205 Calcium ( mg/kg ) 16.88 3.98 29,200 18,600 Magnesium ( mg/kg ) 13.09 0.81 1,100 4,000 Sulfur ( mg/kg ) 18.36 3.29 600 3,400 Iron ( mg/kg ) 1.62 0.26 1,100 1,200 Copper ( mg/kg ) 0.05 0.05 10 300 Manganese ( mg/kg ) 0.04 0.02 80 300 Zinc ( mg/kg ) 0.05 0.03 40 400 Boron ( mg/kg ) 0.13 0.21 50 50 Sodium ( mg/kg ) --800 4,200 Table 2 5 Relevant physical and chemical properties of custom media mixes that represent the compost treatments in the determinate red bell pepp er study in the saw tooth style greenhouse at UF PSREU research farm near Citra, FL in Fall 2010 and Spring 2011 Property NC z YW PL Soluble salts ( mmhos/cm) 0.30 0.61 8.28 C ation exchange c apacity (%) 55.00 38.05 31.65 Bulk d ensity (g / cm 3 ) 0.19 0.37 0 .33 pH 5.18 6.87 6.88 Water holding c apacity (%) 56.02 70.83 91.47 Ammonia n itrogen (mg/kg) 10.50 29.3 2 36.4 0 Nitrate n itrogen (mg/kg) 6.48 7.26 270.46 Phosphorus (mg/kg) 2.24 7.48 183.95 Potassium (mg/kg) 14.85 102.58 2953.99 Calcium (mg/kg) 24.17 60.04 100.25 Magnesium (mg/kg) 17.48 17.86 159.50 Sulfur (mg/kg) 18.20 21.02 383.20 Iron (mg/kg) 0.21 0.23 0.45 Copper (mg/kg) 0.05 0.05 1.52 Manganese (mg/kg) 0.06 0.11 0.48 Zinc (mg/kg) 0.04 0.04 0.44 Boron (mg/kg) 0.49 0.12 0.80 z NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume).

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87 A B Figure 2 6 Inside the greenhouse, air temperature at a height of 1 meter and the temperature of each of t he three media/compost mixes in Fall 2010 A) High temperature. B) Low temperature. C) Average temperature. NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by vo lume).

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88 C Figure 2 6 Continued

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89 Table 2 6 The effects of conventional and organic fertilizer and compost treatments on t otal yields, marketable yields and fruit size distribution (kg/m 2 ) from determinat e red bell pepper plants grown in a saw tooth st yle greenhouse at Total Marketable Size yield yield z distribution by class y (kg/m 2 ) Main effects (kg/m 2 ) (kg/m 2 ) XL L M S U Fertilizer treatment (F) x Convtl 4.00 3.47 a 1.78 a 0.97 0.52 0.19 0.04 Gran Gran 2.59 2.32 b 0.57 b 0.89 0.69 0.16 0.04 Gran Soln 2.45 2.17 b 0.64 b 0.66 0.66 0.20 0.05 Soln Gran 2.10 1.89 b 0.51 b 0.63 0.57 0.18 0.05 Soln Soln 1.56 1.31 c 0.11 c 0.26 0.65 0.30 0.07 P value v <0.0001 <0.0001 <0.0 001 <0.0001 0.6071 0.2000 0.5285 Compost treatment (C) w NC 2.39 2.12 0.63 0.83 0.50 0.15 0.03 YW 2.35 2.15 0.70 0.60 0.63 0.22 0.06 PL 2.87 2.42 0.83 0.62 0.72 0.25 0.06 P value <0.0060 0.3185 0.4198 0.0220 0.0713 0.1 339 0.2922 Interaction (F*C) P value 0.0014 0.0611 0.1231 0.0092 0.0433 0.1893 0.8000 z Market able yield: size classes XL, L, M and S with no external defects Plant density = 3 pl/m 2 y Size classes (by diameter) : U < 55 mm, S = 55 to 64.9 mm, M = 65 to 74.9 mm, L = 75 to 83. 9 x Convtl: conventional mineral based solution injected through irrigation system throughout the season ; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: orga nic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporate d into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. w NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). v P Means with the same letter are not significantly different

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90 A B Figure 2 7 Total yield (kg/m 2 ) interaction effects in Fall 2010. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) F ertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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91 A B Figure 2 8 Yield (kg/m 2 ) (75 83.9 mm in fruit diameter) interaction effects in Fall 2010. Interaction means designated by different letters withi n each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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92 A B Figure 2 9 Yield (kg/m 2 ) (65 74.9 mm in fruit diameter) interaction effects in Fall 2010. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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93 Table 2 7 T he effects of conventional and organic fertilizer and compost treatments on t otal yields, marketable yields and fruit size distribution (kg/m 2 ) from determinate red bell pepper plants grown in a saw tooth style greenhouse at Total Marketable Size yield y ield z distribution by class y (kg/m 2 ) Main effects (kg/m 2 ) (kg/m 2 ) XL L M S U Fertilizer treatment (F) x Convtl 3.55 a 2.21 a 0.64 a 0.51 a 0.72 a 0.34 0.19 ab G ran Gran 2.00 bc 1.40 ab 0.06 bc 0.28 ab 0.68 a 0.35 0.14 bc Gran Soln 2.25 b 1.92 a 0.29 ab 0.52 a 0.71 a 0.41 0.10 c Soln Gran 1.63 c 1.05 b c 0.03 bc 0.17 b 0.51 a 0.34 0.22 a Soln Soln 1.09 d 0.58 c 0.00 c 0.05 b 0.23 b 0.30 0.18 ab P value v <0. 0001 0.0003 0.0137 0.0044 0.0007 0.4592 0.0322 Compost treatment (C) w NC 1.86 1.34 0.10 0.26 0.65 a 0.33 0.16 YW 2.14 1.66 0.28 0.32 0.64 a 0.42 0.17 PL 2.30 1.27 0.23 0.34 0.41 b 0.29 0.18 P value 0.0990 0.1767 0.7738 0 .7371 0.0231 0.0151 0.7636 Interaction (F*C) P value 0.3133 0.5992 0.3354 0.9086 0.4608 0.0442 0.1042 z M arketable yield: size classes XL, L, M and S with no external defects Plant density= 3 pl/m 2 y Size classes (by diameter) : U < 55 mm, S = 55 to 64.9 mm, M = 65 to 74.9 mm L = 75 to 83.9 x Convtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorpor ated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sided ress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. w NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litt er compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). v P Means with the same letter are not significantly different.

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94 A B Figure 2 1 0 Yield (kg/m 2 ) (55 64.9 mm in fruit diam e ter) interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not sign ificantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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95 Table 2 8 The effects of conventional and organic fertil izer and compost treatments on yield of culled fruit (kg/m 2 ) from determinate red bell pepper plants grown in a saw Fall 2010 Fruit external defects (kg/m 2 ) Total Blosso m Radial Flat Mis Main effects culls z end rot Sunscald cracking shape shapen Russeting Fertilizer treatment (F) y Convtl 0.49 a 0.34 a 0.03 0.01 0.07 a 0.03 0.00 Gran Gran 0.24 b 0.12 b 0.07 0.01 0.02 b 0.01 0.01 Gran Soln 0.24 b 0.10 b 0.07 0.02 0.01 b 0.03 0.00 Soln Gran 0.16 b 0.05 b 0.01 0.00 0.08 a 0.02 0.00 Soln Soln 0.18 b 0.04 b 0.06 0.02 0.01 b 0.03 0.01 P value w 0.0165 0.0026 0.4479 0.2752 0.0066 0.7490 0.3882 Compost treatment (C) x NC 0.24 b 0.13 b 0.03 b 0.01 0.04 0.02 0.00 YW 0.14 b 0.06 c 0.01 b 0.02 0.03 0.03 0.01 PL 0.40 a 0.20 a 0.11 a 0.01 0.04 0.03 0.01 P value 0.0084 0.0 003 0.0029 0.6050 0.5508 0.7698 0.6355 Interaction (F*C) P value 0.8940 0.6571 0.3079 0.3894 0.4568 0.4036 0.7825 z Total culls includes the sum of blossom end rot, sunscald, radial cracking, fla t shape, misshapen and russeting. Plant density = 3 pl/m 2 y Convtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorp orated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. x NC: no compost; YW: 30% yard waste compost by vo lume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). w P Means with the same letter are not significantly diff erent.

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96 Table 2 9 The effects of conventional and organic fertilizer and compost treatments on yield of culled fruit (kg/m 2 ) from determinate red bell pepper plants grown in a saw Fruit external defects (kg/m 2 ) Total Blosso m Radial Flat Mis Main effects culls z end rot Sunscald cracking shape shapen Russeting Fertilizer treatment (F) y Convtl 1.14 0.87 0.13 0.00 0.13 a 0.01 b 0.00 Gran Gran 0.49 0.27 0.11 0. 00 0.10 a 0.01 b 0.00 Gran Soln 0.23 0.04 0.13 0.00 0.03 b 0.02 ab 0.00 Soln Gran 0.37 0.14 0.18 0.00 0.02 b 0.01 b 0.00 Soln Soln 0.33 0.15 0.11 0.00 0.02 b 0.04 a 0.00 P value w <0.0001 <0.0001 0.3297 0.4183 <0.0001 0.0287 NS Compost treatment (C) x NC 0.37 0.18 0.12 0.00 0.05 0.02 0.00 YW 0.31 0.12 0.12 0.00 0.05 0.02 0.00 PL 0.85 0.59 0.17 0.00 0.07 0.01 0.00 P value <0.0001 <0.0001 0.1545 0.3765 0.2504 0.3939 NS Interaction (F*C) P value 0.0204 0.0143 0.4128 0.4504 0.9594 0.0765 NS z Total culls includes the sum of blossom end rot, sunscald, radial cracking, flat shape, misshapen and russeting. Plant density = 3 pl/m 2 y Convtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system begin ning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. To tal season application of N, P, K, Ca and water were consistent across all treatments. x NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). w Means separa P Means with the same letter are not significantly different. NS: not significant because whole data set is zeroes.

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97 A B Figure 2 11 Yield (kg/m 2 ulls ( sum o f blossom end rot, sunscald, radial cracking, flat shape, misshapen and russeting ) interaction effects in Spring 2011 Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no let ters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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98 A B Figure 2 12 Yield of blosso m end rot (kg/m 2 ) interaction effects in Spring 2011. Interaction means designated by differ ent letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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99 Table 2 10 The effects of conventional and organic fertilizer and compost treatments on total yield ( number of fruit per m 2 ) and marketable yield, to tal culls and blossom end rot ( number of fruit per m 2 and percent of total yield by weight ) from determinate red bell pepper plants grown in a saw Citra, FL in Fall 2010 Number of fruit per square meter z Percent of total yield (by weight) w Total Marketable Total Blosso m Marketable Total Blosso m Main effects yield y ield y c ulls x end rot yield C ulls x end rot Fertilizer treatment (F) v Convtl 33.2 26.0 5.8 a 3.3 a 85.8 13.2 9.3 a Gran Gran 22.4 18.3 3.1 b 1.3 b 88.8 9.6 4.5 ab Gran Soln 20.9 17.1 2.6 b 1.0 b 87.2 10.3 4.1 ab Soln Gran 20.2 15.3 3.1 b 1.1 b 89.0 7.5 1.8 b Soln Soln 17.8 13.5 2.7 b 0.8 b 83.4 10.8 2.0 b P value t <0.0001 <0.0001 0.0167 0.0125 0.6522 0.7884 0. 0195 Compost treatment (C) u NC 21.1 17.4 2.7 b 1.2 b 87.3 ab 9.9 ab 4.1 b YW 20.2 16.7 1.8 b 0.5 c 91.3 a 5.5 b 1.5 c PL 27.4 20.0 5.9 a 2.8 a 81.9 b 15.4 a 7.4 a P value <0.0001 0.0003 <0.0001 0.0002 0.021 8 0.0074 <0.0001 Interaction (F*C) P value <0.0001 <0.0001 0.0711 0.5892 0.9928 0.8369 0.5524 z Data log (negative binomial) transformed for analysis. y M arketable yield: fruit with diamet Plant density = 3 pl/m 2 x Total culls includes the sum of blossom end rot, sunscald, radial cracking, flat shape, misshapen and russeting. w Data square root transformed for analysis. v Co nvtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected throug h irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments.

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100 u NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark ( by volume). t P significantly different.

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101 A B Figure 2 13 Total yield (# of fruit/m 2 ) interaction effects in Fall 2010. Interaction means designated by different letters within each x axis treatment are significantly differe nt at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost. A B Figure 2 14 Marketable yield (# of fruit/m 2 ) interaction effects in Fall 2010. Interact ion means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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102 Table 2 11 The effects of conventional and organic fertilizer and compost treatments on total yield ( number of fruit per m 2 ) and marketable yield, total culls and blosso m end rot ( number of fruit per m 2 and percent of total yield by weight ) from determi nate red bell pepper plants grown in a saw Citra, FL in Spring 2011 Number of fruit per square meter z Percent of total yield (by weight) w Total Marketable Total Blosso m Marketable Total Blosso m Main effect s yield yield y culls x end rot yield C ulls x end rot Fertilizer treatment (F) v Convtl 70.0 25.9 a 34.1 a 27.8 52.9 bc 39.9 a 32.0 Gran Gran 42.9 19.8 ab 17.5 b 11.7 62.8 b 29.3 b 16.9 Gran Soln 34.4 24.3 a 4.6 d 1 .1 82.0 a 11.1 c 2.3 Soln Gran 37.9 14.4 b 10.3 c 5.9 57.0 bc 26.2 b 13.4 Soln Soln 31.3 9.1 c 12.1 c 8.3 47.0 c 35.7 ab 14.0 P value t <0.0001 <0.0001 <0.0001 <0.0001 0.0004 <0.0001 <0.0001 Compost treatment (C) u NC 35.6 18 .2 ab 9.5 b 5.4 65.9 a 23.1 b 7.6 YW 37.6 21.5 a 8.1 b 3.9 73.0 a 15.6 b 5.4 PL 56.8 16.4 b 29.5 a 23.5 42.2 b 46.7 a 34.2 P value <0.0001 0.0272 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 Interaction (F*C) P value 0.0004 0.164 5 0.1027 0.0050 0.2431 0.1834 0.0038 z Data log (negative binary) transformed for analysis. y Ma Plant density = 3 pl/m 2 x Total culls includes the sum of blossom end rot, sunscald, radial cracking, flat shape, misshapen and russeting. w Data square root transformed for analysis. v Co nvtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution in jected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments.

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103 u NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a med ia base of 1 peat : 1 pine bark (by volume). t P significantly different. A B Figure 2 15 Total yield (# of fruit/m 2 ) interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly diff erent at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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104 A B Figure 2 16 Yield of blosso m end rot (# of fruit/m 2 ) interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost slice d by Compost. A B Figure 2 17 Percent blosso m end rot (BER) interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not signi ficantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost

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105 Table 2 12 The effects of conventional and organic fertilizer and compost treatments on plant height and leaf SPAD values of determinate red bell pepper plants grown in a saw 2010 Days after transplanting Plant height (cm) z Leaf SPAD values y Main effects 17 40 17 40 60 86 Fertilizer treatment (F) x Convtl 24 .8 47.1 52.6 a 68.1 a 72.6 a 74.2 a Gran Gran 26.4 44.2 51.6 a 58.1 b 65.5 bc 64.4 bc Gran Soln 23.7 41.2 46.8 b 60.8 b 61.1 d 61.4 c Soln Gran 26.6 40.6 51.6 a 58.9 b 66.3 b 67.9 b Soln Soln 26.4 40.3 50.3 a 60.2 b 61.9 cd 63.3 c P val ue v 0.0511 <0.0001 0.0155 0.0002 <0.0001 <0.0001 Compost treatment (C) w NC 24.3 b 41.2 52.8 a 64.3 a 66.4 66.9 YW 25.2 b 41.1 48.0 b 56.4 b 63.6 65.9 PL 27.3 a 45.7 51.0 a 62.9 a 66.4 66.0 P value 0.0041 0.0001 0.0027 <0.0001 0.0870 0.7495 Interaction (F*C) P value 0.5405 0.0029 0.7912 0.2153 0.3255 0.2224 z Plant height was measured from the media surface to the last node of the longest stem on all four center plants in each plot. y Leaf SPAD values: measured o n the most recently fully expanded leaf of the four center plants a representation of leaf nitrogen status. x Convtl: conventional mineral based solution injected through irrigation system thro ughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. w NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). v Means separated within columns by F P Means with the same letter are not significantly different.

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106 A B Figure 2 18. Plant height (cm) at 40 days after transplant (DAT) interaction effects in Fall 2010. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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107 Table 2 13 The effects of conventional and organic fertilizer and c ompost treatments on plant height and leaf SPAD values of determinate red bell pepper plants grown in a saw FL in Spring 2011 Days after transplanting Plant height (cm) z Leaf SPAD values y Main effects 2 1 44 56 89 21 44 56 89 Fertilizer treatment (F) x Convtl 26.5 a 46.1 51.8 a 63.5 a 63.9 64.1 a 66.5 a 75.1 a Gran Gran 23.6 b 42.2 46.8 b 52.8 bc 60.2 60.0 b 60.6 b 55.5 c Gran Soln 24.2 b 44.9 49.5 ab 54.2 b 57 .9 58.2 b 55.2 c 55.8 c Soln Gran 24.6 b 36.5 42.0 c 49.3 c 53.8 59.2 b 65.2 a 67.2 b Soln Soln 23.9 b 36.8 40.5 c 49.0 c 56.7 58.3 b 60.0 b 72.3 a P value v 0.0059 <0.0001 <0.0001 <0.0001 <0.0001 0.0009 <0.0001 <0.0001 Compost treatment (C) w NC 23.5 b 39.3 43.6 b 49.8 b 58.7 60.0 b 63.2 a 67.5 a YW 24.4 b 41.6 46.7 a 54.2 a 56.4 56.7 c 60.1 b 65.8 ab PL 25.8 a 42.9 48.1 a 57.3 a 60.4 63.2 a 61.2 ab 62.3 b P value 0.0015 0.0023 0.0017 0.0002 0.0023 <0.0001 0.0382 0.0 241 Interaction (F*C) P value 0.2228 0.0267 0.2162 0.3899 0.0061 0.0824 0.3551 0.3655 z Plant height was measured from the media surface to the last node of the longest stem on all four center plants in each plot. y Leaf SPAD values: mea sured on the most recently fully expanded leaf of the four center plants in each plot; relative numbers that a representation of leaf nitrogen status. x Convtl: conventional mineral based solution injected through irrigation syst em throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedres s; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season appli cation of N, P, K, Ca and water were consistent across all treatments.

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108 w NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). v Means separated within colum P significantly different

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109 A B Figure 2 19. Plant height (cm) at 44 DAT interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly diffe rent at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost. A B Figure 2 20. Leaf SPAD values at 21 DAT interaction effects in Spring 2011. Interactio n means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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110 T able 2 14 The effects of conventional and organic fertilizer and compost treatments on the pH, electrical conductivity (EC) and nitrate (NO 3 N) concentration of leachate over the season from determinate red bell pepper plants grown in a saw tooth style g pH EC (mS/cm) NO 3 N (mg/L) z Main effects 29 DAT y 59 DAT 92 DAT 29 DAT 59 DAT 92 DAT 29 DAT 59 DAT 92 DAT Fertilizer treatment (F) x Convtl 6.7 6.5 c 6.4 c 1.9 a 2.9 a 3.7 a 44.6 a 58.8 a 78.5 a Gran Gran 7.1 7.3 a 7.0 b 1.2 b 0.9 c 2.5 b 4.2 b 0.7 b 9.0 bc Gran Soln 7.2 7.2 ab 7.3 a 1.1 b 1.1 bc 0.8 c 4.1 b 1.6 b 3.1 cd Soln Gran 7.3 7.0 b 7.0 b 0.9 b 1.7 b 2.6 b 4.9 b 1.5 b 16.0 b Soln Soln 7. 1 7.1 ab 7.0 b 1.0 b 1.3 bc 1.1 c 0.9 b 0.6 b 2.4 d P value v 0.0933 <0.0001 <0.0001 0.0025 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 Compost treatment (C) w NC 6.5 c 6.6 b 6.5 c 0.6 c 1.0 b 1.5 b 6.6 b 7.8 15.6 b YW 7.5 a 7.3 a 7.3 a 1.0 b 1.4 b 1.6 b 10.9 b 12.5 12.3 b PL 7.1 b 7.1 a 7.1 b 2.1 a 2.4 a 3.4 a 17.7 a 17.6 37.5 a P value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 0.0163 0.2766 0.0004 Interaction (F*C) P value 0.8903 0.3873 0.2198 0.2582 0.2124 0.2067 0.3047 0.0608 0.1566 z Data square root transformed for analysis. y DAT: days after transplanting. x C onvtl: conventional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular i ncorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigat ion system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. w NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). v a P significantly different.

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111 Table 2 15 The effects of conventional and organic fertilizer and compost treatments on the pH, electrical conductivity (EC) and nitrate (NO 3 N) concentration of leachate over the seaso n from determinate red bell pepper plants grown in a saw pH EC (mS/cm) z NO 3 N (mg/L) y Main effects 30 DAT x 52 DAT 73 DAT 30 DAT 52 DAT 73 DAT 30 DAT 52 DAT 73 DAT Fertilizer tre atment (F) w Convtl 6.4 6.4 6.1 b 2.0 2.2 bc 3.3 a 46.4 a 31.6 a 67.4 a Gran Gran 6.5 6.5 6.5 a 2.5 3.3 a 2.5 ab 22.8 b 38.7 a 11.4 b Gran Soln 6.7 6.6 6.6 a 1.5 1.0 d 1.1 c 11.8 b 1.7 b 1.3 c Soln Gr an 6.6 6.4 6.6 a 1.6 2.4 ab 2.1 b 35.3 a b 24.3 a 13.5 b Soln Soln 6.6 6.5 6.4 a 1.8 1.7 cd 1.8 c 22.7 b 7.7 b 3.3 c P value u 0.2756 0.4923 0.0065 <0.0001 <0.0001 <0.0001 0.0242 <0.0001 <0.0001 Compost treatment (C) v NC 6. 4 b 6.2 b 6.2 b 0.9 1.6 b 1.5 b 14.2 b 13.1 b 10.9 b YW 6.6 a 6.6 a 6.6 a 1.3 1.5 b 1.5 b 8.5 b 14.4 b 19.6 b PL 6.7 a 6.6 a 6.6 a 3.5 3.3 a 3.4 a 60.6 a 34.9 a 27.6 a P value 0.0214 0.0010 0.0004 0.1267 <0.0001 <0.0001 <0.0001 0.0003 0.0131 Interaction (F*C) P value 0.1518 0.9417 0.9105 0.0017 NS NS 0.1380 0.4651 0.1680 z Data transformed to fit a censor data model for analysis. y Data square root transformed for analysis. x DAT: days after transplanting. w Convtl: conv entional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic s olution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected thr ough irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. v NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume).

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112 u P significantly different A B Figure 2 21. Electrical conductivity (EC) of leachate ( mS/cm) at 30 DAT interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost slic ed by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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113 Table 2 16 The effects of conventional and organic fertil izer and compost treatments at harvest on whole plant dry weight, leaf percent total k jeldahl n itrogen (TKN), and fruit pericarp thick ness, lobe n umber, fresh weight, dry weight percent TKN and percent nitrogen use efficiency (NUE) from determinate red bell pepper plants grown in a saw tooth style greenhouse Fall 2010 Whole Pericarp Fruit plant dry Leaf thickness lobe Fruit fresh Fruit dry Fruit Fruit Main effects weight (g) TKN (%) (mm) number weight (g) weight (g) TKN (%) NUE (%) z Fertilizer treatment (F) y Convtl 50.3 3.47 a 6.06 a 3.73 323 a 18.16 a 2.59 19. 33 a Gran Gran 25.3 2.83 c 5.65 b 3.63 288 ab 18.06 a 1.88 10.04 b Gran Soln 23.2 2.85 c 5.41 bc 3.59 256 b 15.66 b 1.86 8.94 b Soln Gran 22.7 3.16 b 5.53 b 3.58 273 b 18.39 a 2.19 9.78 b Soln Soln 16.4 3.10 b 5.13 c 3.60 193 c 12.65 c 1.98 6.61 c P value w <0.0001 <0.0001 <0.0001 0.3359 <0.0001 <0.0001 <0.0001 <0.0001 Compost treatment (C) x NC 24.5 3.24 a 5.58 3.55 b 253 16.18 2.09 10.45 b YW 25.5 2.98 b 5.60 3.60 ab 273 16.31 2.09 9.76 b PL 32.7 3.02 b 5.49 3.73 a 272 17.27 2.11 12.61 a P value 0.0001 0.0031 0.6562 0.0208 0.4057 0.3330 0.9505 0.0028 Interaction (F*C) P value 0.0048 0.1051 0.3025 0.4091 0.3174 0.3647 0.0001 0.0736 z NUE: calculated using total yield values. y Convtl: conve ntional mineral based solution injected through irrigation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic so lution injected through irrigation system beginning at sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected thro ugh irrigation system throughout the season. Total season application of N, P, K, Ca and water were consistent across all treatments. x NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume).

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114 w P significantly different.

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115 A B Figure 2 22 Whole plant dry weight (g) at harvest interaction effects in Fall 2010 Interaction means designated by different letters within each x axis treatment are significantl y different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost. A B Figure 2 23 Fruit percent TKN at harvest interaction effects in Fall 2010 Int eraction means designated by different letters within each x axis treatment are significantly different at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Comp ost.

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116 Table 2 1 7 The effects of conventional and organic fertil izer and compost treatments at harvest on whole plant dry weight, leaf percent total k jeldahl n itrogen (TKN), and fruit pericarp thickness, lobe numb er, fresh weight, dry weight percent TKN and percent nitrogen use efficiency (NUE) from determinate red bell pepper plants grown in a saw tooth style greenhouse Spring 201 1 Whole Pericarp Fruit plant dry Leaf thickness lobe Fruit fresh Fruit dry Fruit Fruit Main effects weight (g) TKN (%) (mm) number weight (g) weight (g) TKN (%) NUE (%) z Fertilizer treatment (F) y Convtl 88.7 a 5.21 a 4.57 a 3.85 220 a 13.97 3.07 a 21.91 a Gran Gran 45.9 b 2.87 d 4.20 a c 3.85 175 bc 14 .27 1.89 c 9.79 b Gran Soln 46.1 b 2.71 d 4.32 ab 3.75 194 ab 14.09 1.93 c 10.20 b Soln Gran 31.0 c 3.26 c 4.15 bc 3.67 159 c 13.56 2.31 b 10.20 b Soln Soln 31.3 c 3.73 b 3.87 c 3.62 147 c 11.41 2.44 b 6.73 b P value w <0.0001 <0.0001 0.0191 0.00 04 0.0001 0.2182 <0.0001 <0.0001 Compost treatment (C) x NC 41.0 b 3.64 4.21 3.67 170 12.85 2.40 11.01 YW 44.3 b 3.48 4.35 3.76 192 13.96 2.28 11.52 PL 60.5 a 3.55 4.10 3.81 175 13.56 2.30 12.76 P value <0.0001 0.40 96 0.2952 0.0123 0.1379 0.5670 0.35 29 0.5305 Interaction (F*C) P value 0.1751 0.0783 0.2776 0.0227 0.1618 0.4493 0.2865 0.8710 z NUE: calculated using total yield values. y Convtl: conventional mineral based solution injected through irrig ation system throughout the season; Gran Gran: organic granular incorporated into media at transplanting and sidedress; Gran Soln: organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning a t sidedress; Soln Gran: organic solution injected through irrigation system beginning at transplanting and organic granular incorporated into media at sidedress; Soln Soln: organic solution injected through irrigation system throughout the season. Total se ason application of N, P, K, Ca and water were consistent across all treatments. x NC: no compost; YW: 30% yard waste compost by volume; PL: 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume).

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117 w Means separated wi P significantly different. A B Figure 2 24. Fruit lobe number at harvest interaction effects in Spring 2011. Interaction means designated by different letters within each x axis treatment are significantly di fferent at P 0.05. Means with no letters are not significantly different. A) Fertilizer x Compost sliced by Fertilizer. B) Fertilizer x Compost sliced by Compost.

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118 CHAPTER 3 ECONOMIC ANALYSIS Materials and Methods T he data used in this ec onomic analysi s were from experiments conducted at the in Marion County, near Citra, Florida in Fall 2010 and Spring 2011. Site Description The experiment was conducted in Fall 2010 and Sprin g 2011 in a multi bay, 2023 m 2 passively ventilated, saw tooth style greenhouse (Top Gr eenhouses Ltd., Barkan, Israel) The high roof structure is covered with UV absorbing polyethylene film, the ventilated side walls and roof vents are covered with 50 me sh insect screen and the floors are covered in white landscape fabric. The experiment was established in one bay of the greenhouse, where 0.15 m diameter polyvinyl chloride (PVC) pipe s were placed in four rows (1.2 m apart) down the north south length of t he greenhouse to serve as a drainage system. Because the experiment contained a conventional fertilizer treatment for comparison, the greenhouse was not certified organic. Pest management was achieved using biological control methods as described below, an d no prohibited pesticides were applied in the greenhouse for six months prior to and during the course of the experiment. Experimental Design Overview An experiment was arranged as a randomized complete block design with treatments replicated four times t o evaluate the effects of fertilizer and media source and form

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119 Mount Vernon, WA) in Fall 2010 and Spring 2011. Treatments were a factorial combination of five fertilizer treatments (one conventional hydroponic and four organic compliant) and three compost treatments (no compost, 30% yard waste compost or 30% poultry litter compost) for a total of 15 treatments. yielding and top qualit y determinate variety well adapted to Florida climate (Shuler, 2003) which could potentially be grown in three crops per year (spring, summer and fall); it is resistant to Bacterial Leaf Spot ( Xanthomonas axonopodis pv. vesicatoria races 1 3), Tobacco Mosa ic Virus and Potato Virus Y strain which is important in an organic compliant growing system that does not use chemicals for disease suppression; and it is an early mid maturing variety which would allow growers to target specific market windows. On 13 Sep t. 2010 and 9 Mar. 2011, bell pepper seedlings were transplanted into 11.4 L black polyethylene nursery pots (C1200, BWI Co Inc Apopka, FL) with two 1.5 cm diameter drainage holes drilled equidistant from each other and 3.8 cm from the bottom of the pot to create a reservoir. Pots were placed on the four rows of PVC pipe, and each row of pipe comprised one block of the experiment. P lots contained six plants (one plant per pot) arranged in a row, for a total of 60 plots and 360 plants. Plants within each r ow were 30 cm apart and between row spacing was 120 cm from center to center for a plant density of three plants per m 2 The center four plants in each plot were harvested by hand on 2 and 9 Dec 2010 [80 and 87 days after transplant (DAT) respectively ] an d 18 May, 25 May and 7 June 2011 (70, 77 and 90 DAT respectively ). Fertilizer treatments mix of mineral based fertilizers and was injected through the irrigation system throughout the

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120 season based on a nutrient levels and irrigation schedule formulated for hydroponic gree nhouse grown bell peppers (Jovicich et al. 2004). The organic granular fertilizer x of four OMRI approved sources and was incorporate d directly into the media either at transplant or at sidedress depending on the mix of th ree OMRI approved sources and was injected through the irrigation system beginning either at transplant or at sidedress depending on the treatment. Sidedress fertilizers were applied on 13 October 2010 and 9 April 2011. The five fertilizer treatments were as follows: Convtl: mineral applied throughout the season Gran Gran Soln ss Soln season Total season applications of N, P, K and Ca were consistent across all treatments (i.e., 10,220, 3513, 13,365 and 11,692 mg per plant, respectively). In conventiona l greenhouse hydroponic fertigation production systems, all nutrients are typically metered out via the irrigation system with each irrigation event throughout the season allowing precise control over nutrient applications, and calcium is usually injected separately from phosphorus and sulfur because they precipitate when mixed together In field production systems that utilize fertigation, most, if not all, of the phosphorus is applied in granular form at planting because it is relatively less soluble (esp ecially if it is derived from organic sources), and can clog the irrigation system if

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121 injected. In field systems, at least half of the nitrogen and potassium are applied in granular form at planting, but the other half is injected through the irrigation sy stem so that the nutrient supply can be controlled and adjusted according to plant dema nd during the season An advantage shared by both the greenhouse and field fertigation methods is the reduced risk of fertilizer leaching and salt toxicity in young plan ts because these methods supplant heavy fertilizer applications early in the season. The application timing and strategies of the organic fertilizer treatments in this study were based on these basic principles in addition to the goal of keeping total seas on N, P, K and Ca consistent across treatments. Application of Convtl fertilizer. Two fertilizer proportional injectors ( MiniDos 2.5%, Dosmatic U.S.A., Inc Carrollton, TX) placed in series were used to pump mineral based stock solution into the irrigati on water (dilution rate 1:50; v/v) from two 18.9 L buckets according to conventional hydroponic greenhouse practices that keep calcium separate from both phosphorus and sulfur to prevent precipitation. Application of Gran fertilizer. At transplanting, th incorporated into the top 15 cm of the media in the pots. The depth was chosen because it is the most biologically active zone for transforming organic sources of nutrients into plant available forms izer was incorporated into the top 8 cm to avoid damaging plant roots. Application of Soln fertilizer. A fertilizer proportional injector was used to pump organic stock solution into irrigation water (dilution rate 1:50; v/v) from an 18.9 L bucket for ea ch of the three fertilizer treatments involving incidence of clogging, new organic stock solutions were made weekly emitters were

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122 frequently checked for clogging and flushed out, the dilution ratio of 1:50 was chosen to feed a less c oncentrated fertilizer solution and all filters were cleaned at least twice a week (Rippy et al., 2004 Zhai et al., 2009 ) Compost treatments All pots received a media base mix of 1 peat : 1 pine bark (by volume). The OMRI approved peat (Sunshine Peat Mos s; Sun Gro Horticulture Canada Ltd, Orlando, FL) was custom mixed with dolomitic limestone for a target pH between pH 5.5 and pH 6.5. The OMRI approved pine bark (Elixson Wood Products, Starke, FL) was screened to a size less than 2.5 x 2.5 cm. The three c ompost treatments were as follows: NC: no compost YW: 30% yard waste compost by volume PL: 30% poultry litter compost by volume The OMRI approved yard waste compost was locally sourced (Gainesville Wood Resource and Recovery, Gainesvill e, FL) was screened to 0.95 cm The poultry litter compost was sourced from a local organic farm certified by Quality Certification Services, Gainesville, FL ) and was composed of 100% poultry manure and pine sawdust from a neighboring po ultry producer. The compost was screened to 1.27 cm Irrigation system Untreated well water was used for irrigation. W ater was delivered through black 1.9 cm diameter poly ethylene pipe (John Deere Landscapes, Gainesville, FL) with or without fertilizer de pending on the treatment. Previous studies ( Rippy et al., 2004; Zhai et al., 2009) have found that typical hydroponic greenhouse emitters with a flow rate of 1.9 L/h or less are readily clogged by fertilizer solutions made from organic sources; therefore in this study, each plant received the irrigation through a 7.6 L/h pressure

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123 compensated emitter on the end of a 60 cm long spaghetti tube. Other measures taken to avoid clogging issues included using poly ethylene pipe and spaghetti tubing with diameters l arger than normal for hydroponic greenhouse operations, incorporating three filters before the fertilizer proportional injectors in order to filter out particulates from the well water and drawing each stock solution u p through its own filter Irrigation duration and frequency was automated using a timer, was consistent across all treatments and was increased over the course of the season to meet plant demand (ranging from 300 to 1500 mL/plant/day). Although the fertilizer proportional injectors were all o perated on the same timer, each was connected to its own solenoid and separate program on the timer to allow them to run individually and avoid reductions in pressure. Crop Seasonal Management Temperature control and trellising Throughout the season, the greenhouse polyethylene side curtains were manually lowered when air temperatures were less than 18C or during periods of rainfall and were raised when air temperatures were greater than 25C. Thermal tu bes (Polyon, Barkai, Israel) and aluminized thermal screens were used when air temperatures were less than 10C (Jovicich et al., 2005 ; Jovicich et al. 2007 ). In high temperatures, fans were used to improve air circulation. system as the plants were a deter minate growth structure (Jovicich et al., 2004; Saha and Cantliffe 2009). Pairs of vertical poles and horizontal twine supported the plants on both sides of the rows, and twine was placed every vertical 20 cm as the plants grew.

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124 Integrated pest management practices No chemical means of pest co ntrol were used in this study. Plants were scouted on a weekly basis or more often as needed to identify disease occurrence and increasing pest thresholds. Pests were controlled using integrated pest management (IPM) practices, including biological control with banker plant systems and alternate hosts that help to sustain beneficial insect populations but do not negat ively affect bell pepper crops ( Jo vicich et al., 2004; Osborne and Barrett 2005; Saha and Cantliffe 2 009 ; Shaw and Cantliffe, 2002 ). Alternate host grain aphids were reared on sorghum banker plants in order to sustain the beneficial parasitic wasp colonies ( Aphidius colemani ) that control the aphid pests. Alternate host papaya whiteflies were reared on pa paya banker plants in order to sustain the beneficial parasitic wasp colonies ( Encarsia formosa and Eretmocerus eremicus ) that control the whitefly pests. Alternate host grass mites were reared on sorghum banker plants in order to sustain the beneficial pr edatory mite colonies ( Amblyseius swirskii Neoseiulus cucumeris and Neoseiulus californicus ) that control mite and thrip pests. Additionally, sticky cards were used to trap winged pests such as fungus gnats, and diligent sanitation habits were observed du ring the course of the season Bumblebees ( Bombus impatiens ) were introduced for supplementary pollination to aid in fruit set; one bee hive per season serviced 650 to 1115 m 2 (Jo vicich et al. 2004; Saha and Cantliffe, 2009; Shaw and Cantliffe 2002). Ben eficials ( i.e., Aphipar, Enermix, Swirski Mite, Thripex V and Spical) and bumblebees ( i.e., NATUPOL class B) were acquired from Koppert Biological Systems in Romulus, Michigan. The seedlings were transplanted to the depth of the cotyledonary node level a nd the emitter placed at the base of the seedling at transplant was gradually moved back

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125 from the base of the plant over the course of 4 weeks. These IPM measures were taken which could predispose the plants to a Fusarium infection (Jovicich and Cantliffe 2004) Fruit Yields Harvest Bell pepper fruit were harvested by hand on 2 and 9 Dec 2010 (80 and 87 DAT respectively ) and 18 May, 25 May and 7 June 2011 (70, 77 and 90 DAT respectively ). Using a slide ruler, all peppers on the center four plants of each plot were graded by size according to a fresh market diameter scale used for imported greenhouse grown bell peppers (Jovicich et al., 2004 ; Saha and Cantliffe, 2009 ). Market able fruit were graded as extra large ( XL 84 mm), large ( L = 75 to 83.9 mm), medium ( M = 65 to 74.9 mm) or small ( S = 55 to 64.9 mm) with no serious external defects. Unmarketable fruit were less than 55 mm in diameter or had at least one of the six major bell pepper external defects: b lossom end rot, sunscald, r adial cracking, flat shape, mis shapen or russeting. Weight of fruit in each of the five size categories and six cull categories were recorded per plant. Statistical a nalysis Combined analyses of variance (ANOVA) among years (Fall 2010 and Spring 2011) indicated significant treatment and year interactions. This may have been attributed to the seasonal variation in growing conditions and the resulting differences in irrigation scheduling as well as to the minor adjustments made when the study was repeated in Spring 2011. Therefore separate statistical analyses for each year were conducted to evaluate the effect of fertilizer treatment, compost treatment and their interaction on organic greenhouse grown bell pepper production In each year, the two

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126 highest yielding conventional treatments (Convtl x NC and Convtl x YW) and the two highest yielding organic treatments (Gran Gran x PL and Gran Soln x PL) were selected for use in the economic analysis. Economic Analysis A partial budget ana lysis can be used to examine the effects of changes in costs of certain pr oduction inputs on the change in profit of an agriculture system ( Barrett et al., 2012; Cantliffe et al. 2008; Jovicich et al. 2005; Rivard et al., 2010) This technique was utilized to focus on the portion of the budget that differs between treatments of interest, rather than the entire budget. A partial budget analysis was conducted using data acquired during this hydroponic greenhouse bell pepper study to compare the potential part ial net returns from conventional vs. organic production methods. The portion of the budget that differed between the conventional and organic treatments of interest was the nutrient management system, i.e. the fertilizer inputs, the media inputs and parts of the hydroponic fertigation system. All other costs for materials and labor were not included in the partial budget analysis because they were consistent across all tr eatments in the study and will vary considerably from grower to grower These o ther pr oduction, harvest, and packing costs (e.g. site preparation, greenhouse structure, irrigation and climate control systems, electrical and drainage systems, growing containers, trellis accessories, IPM materials, pollinators, energy, packing cartons, labor, etc.) must be factored in by the grower to achieve a full net retu rn. Sources and prices for the nutrient management system materials of interest that were used to perform the partial budget analysis were identified (Table 3 1) for estimating the differen tial cost of producing hydroponic greenhouse grown red bell pepper under the two conventional treatments (Convtl x NC and Convtl x YW) and the

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127 two organic treatments (Gran Gran x P L and Gran Soln x PL) (Table 3 2 ). The amount and cost of each material used for each of the four treatments was based on one 4 month determinate bell p epper crop and Fall 2010 price estimates from manufacturing companies for a population of 1000 plants The MiniDos 2.5% fertilizer proportional injector used in the experiment has a 45 L/ m in flow rate and can service 360 plants fed by 7.6 L/ h emitters ; this information was used to calculate the quantity and cost of the equipment per 1000 plants based on a straight line depreciation applied for five expected years of use The total c ost per plant and per square meter of greenhouse area (based on a plant density of 3 plants/m 2 ) for each of the four treatments was then calculated from the total cost of nutrient management for 1000 plants. Sensitivity analyses were conducted to compare p artial net returns for determinate red bell pepper plants grown under conventional and organic greenhouse nutrient management systems Gross revenue was estimated by multiplying the wholesale market price ($/kg) by the marketable fruit yield (kg/m 2 ). The p artial net returns ($/m 2 ) were calculated by subtracting the nutrient management cost from the gross revenue. The yields used in the sensitivity analyses were the mean yield per square meter 3 standard errors to provide a 99% confidence interval of expect ed yields. The mean yields and standard errors for each of the four nutrient management treatments were estimated from the analyses of yield data from the Fall 2010 and Spring 2011 greenhouse trials separately. The prices used in the sensitivity analyses are expressed in terms of 5 kg cartons because this is the typical packaging unit for greenhouse grown bell pepper. The range of prices and the mean price for each analysis was based on historical price data

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128 collected from the U.S. Department of Agricultur e Fruit and Vegetable Market News Portal ( U.S. Dept. of Agriculture, 2012a ) For the sensitivity analyses of Convtl x NC and Convtl x YW treatments, prices per kg were calculated from published weekly average wholesale market prices for transactions of 5 kg cartons of imported, conventional greenhouse grown, red bell peppers at the Atlanta terminal market during December in years 2004 2011 (for the Fall 2010 analysis) and during May in years 2004 2012 (for the Spring 2011 analysis) ( U.S. Dept. of Agricultu re, 2012a ) For the sensitivity analyses of Gran Gran x PL and Gran Soln x PL, prices per kg were calculated from published weekly average wholesale market prices for transactions of 5 kg cartons of imported, organic greenhouse grown, red bell peppers at t he Atlanta, Boston, Chicago and Philadelphia terminal markets during D ecember in years 2004 2011 (for the Fall 2010 analysis) and during May in years 2005 2012 (for the Spring 2011 analysis ) ( U.S. Dept. of Agriculture, 2012a ) Price data were gathered from the three other markets in addition to the Atlanta mark et because organic price data are more scarce. Results and Discussion Nutrient Management Cost Analysis Sources and prices for materials used in hydroponic greenhouse production of conventional and org anic red bell peppers is presented in Table 3 1. Organic inputs are often more expensive than conventional inputs. However, the results of this cost analysis show that this is not always the case. With diligent research on the kinds and availabilities of O MRI approved organic inputs and locally sourcing as many of the chosen inputs as possible, it is feasible to reduce the organic input costs to those of conventional or even, as in this case, render them less expensive than conventional. In this study, the nutrient management input cost s of the Convtl x NC, Convtl x YW, Gran

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129 Gran x PL and Gran Soln x PL treatments were $3.58, $3.08, $2.31 and $2.94 per square meter, respectively (Table 3 2). A large proportion of this cost difference is attributed to the cos t of p eat moss as a media component. Although peat is a popular and effective hydroponic greenhouse soilless media, it is substantially more expensive at $86/yd 3 compared to the cost of the other media ingredients of pine bark, poultry litter compost and y ard waste compost ($8.25, $10 and $15/yd 3 respectively). The Convtl x NC treatment used media made of 1 peat : 1 pine bark (by volume), whereas the other treatments incorporated 30% compost into the media mix, reducing the amount of peat in the mix from 5 0% to 35% resulting in a 30% decrease in media costs. While compost is particularly beneficial in organic fertility programs like the Gran Gran x PL and Gran Soln x PL treatments, its use is not traditionally popular or necessary in systems that use conve ntional hydroponic fertility programs. However, one of the conventional treatments explored in this study was Convtl x YW, in which yard waste compost was incorporated into the media and coupled with conventional hydroponic fertilizers. The result was lowe r media costs (as previously discussed) and, surprisingly, higher yields when compared with the Convtl x NC control treatment. Therefore, this treatment was included in the sensitivity analyses in order to compare the best case scenario of the conventional treatments with that of the organic treatments in the greenhouse production study. One of the reasons why the two organic treatments were still less expensive than even the Convtl x YW treatment is the difference in compost prices. The poultry litter comp ost used in the two organic treatments is 33% less expensive than the yard waste compost used in the Convtl x YW treatment.

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130 Total fertilizer costs per 1000 plants for the Convtl x NC, Convtl x YW, Gran Gran x PL and Gran Soln x PL treatments were $226.36, $226.36, $146.71 and $280.30, respectively. Many organic fertilizer sources can be cost prohibitive, however the granular nature and local sourcing of the Gran Gran x PL treatment organic fertilizer inputs proved effective in terms of cost reduction as we ll as yield, costing 35% less than the conventional mineral based fertilizer inputs used in the Convtl x NC and Convtl x YW treatments. The Gran Soln x PL treatment received half of its total season nutrients via the organic granular fertilizer inputs and the other half of its total season nutrients via dry finely ground organic fertilizer inputs that were mixed with water to create an organic nutrient solution that was then fertigated to the plants. The HFPC spray dried hydrolyzed fish protein that made up a large proportion of this organic nutrient solution was more costly compared to the organic granular fertilizer inputs and so almost doubled the total fertilizer costs compared to Gran Gran x PL treatment. However, the higher costs of the fertilizers in this organic treatment was not cost prohibitive, and total nutrient management cost of this organic treatment was still lower than that of the conventional treatments, primarily due to the reduction of peat in the media and the use of less fertilizer propo rtional injectors. Also, liquid organic fertilizers are more expensive that dry, therefore I chose the dry, fine ly ground, solution grade fertilizer to dissolve in water to make the organic nutrient so lution rather than utilizing an expensive liquid option In conventional greenhouse hydroponic fertility programs, calcium and iron are mixed into a separate nutrient solution from the rest of the elements in order to avoid precipitation problems. As a result two separate mineral based nutrient solutions are

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131 m ade and injected into the irrigation system via two separate fertilizer proportional injectors. As a result, the Convtl x NC and Convtl x YW treatments incurred the cost of twice as many injectors as the Gran Soln x PL treatment, while the Gran Gran x PL t reatment did not require any injectors at all. This also contributed to the lower total nutrient management costs of the two organic treatments compared to the two conventional treatments. Sensitivity Analysis A sensitivity analysis was used to examine ho w partial ne t returns changed under various combinations of marketable bell pepper yields and market prices and to compare the returns under these varying situations of the two conventional and two organic greenhouse nutrient management treatments. Exclud ing the differences in nutrient management input costs, overall production costs would be similar across all four treatments. This study focused on organic greenhouse red bell pepper production because the higher market prices of red bell pepper compared t o green, greenhouse grown compared to field grown peppers and organic produce compared to conventional produce highlights this as a potentially lucrative market niche for growers to expand into. Because many conventional greenhouse growers use soilless hyd roponic systems, this study focused on the feasibility of these growers to use their existing hydroponic infrastructure and materials and modify it for successful organic greenhouse production. By adapting the existing greenhouse system, the costs of trans itioning from conventional to organic production would be minimized. The results of the Fall 2010 sensitivity analyses are presented in Tables 3 3 and 3 4. December wholesale market prices for conventional greenhouse grown red bell peppers ranged from $14 to $35.50/5 kg carton, and the 99% confidence interval of

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132 expected prices for that range was used in the analyses ($15.75 to $33.75/5 kg carton). December wholesale market prices for organic greenhouse grown red bell peppers ranged from $26 to $60/5 kg car ton, and the 99% confidence interval of expected prices for that range was used in the analyses ($29.50 to $56.50/5 kg carton). Convtl x NC plants produced a mean marketable yield of 3.49 kg/m 2 and at that yield for the mean conventional greenhouse grown red bell pepper price of $24.75/5 kg carton, the estimated partial net return was $13.68/m 2 Convtl x YW plants produced a mean marketable yield of 4.01 kg/m 2 and at that yield for the mean conventional greenhouse grown red bell pepper price of $24.75/5 k g carton, the estimated partial net return was $16.79/m 2 Convtl x YW treatment achieved a higher partial net return than Convtl x NC because it produced greater yields and incurred lower nutrient management costs. Gran Gran x PL plants produced a mean mar ketable yield of 2.34 kg/m 2 and at that yield for the mean organic greenhouse grown red bell pepper price of $43.00/5 kg carton, the estimated partial net return was $17.79/m 2 which is $4.11/m 2 and $1.00/m 2 more than the partial net return of the Convtl x NC and Convtl x YW treatments, respectively. Gran Soln x PL plants produced a mean marketable yield of 2.37 kg/m 2 and at that yield for the mean organic greenhouse grown red bell pepper price of $43.00 /5 kg carton, the estimated partial net return was $ 1 7.46 /m 2 which is $3.78/m 2 and $0.67/m 2 more than the partial net return of the Convtl x NC and Convtl x YW treatments, respectively. Gran Soln x PL nutrient management input cost of $2.94/m 2 was slightly higher than that of Gran Gran x PL at $2.31/m 2 ho wever the slightly higher yield of the Gran Soln x PL treatment offset this extra cost and resulted in a partial net return comparable to that of Gra n Gran x PL. Although the yield achieved by the Gran

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133 Gran x PL treatment was lower than the yield achieved by the Convtl x NC and Convtl x YW treatments (by 33 and 42%, respectively) the lower nutrient management input cost of the organic treatment compared to the conventional treatments (by 35 and 25%, respectively) and the higher average market price (by 74% ) resulted in a 30 and 6%, respectively, increase in partial net return for the organic treatment compared to the conventional treatments. Although the yield achieved by the Gran Soln x PL treatment was lower than the yield achieved by the Convtl x NC and Convtl x YW treatments (by 32 and 41%, respectively), the lower nutrient management input cost of the organic treatment compared to the conventional treatments (by 18 and 5%, respectively) and the higher average market price (by 74%) resulted in a 28 and 4 %, respectively, increase in partial net return for the organic treatment compared to the conventional treatments. The results of the Spring 2011 sensitivity analyses are presented in Tables 3 5 and 3 6. May wholesale market prices for conventional greenh ouse grown red bell peppers ranged from $13.50 to $42.00/5 kg carton, and the 99% confidence interval of expected prices for that range was used in the analyses ($15.75 to $39.75/5 kg carton). May wholesale market prices for organic greenhouse grown red be ll peppers ranged from $33 to $54.50/5 kg carton, and the 99% confidence interval of expected prices for that range was used in the analyses ($34.75 to $52.75/5 kg carton). Convtl x NC plants produced a mean marketable yield of 1.78 kg/m 2 and at that yiel d for the mean conventional greenhouse grown red bell pepper price of $27.75/5 kg carton, the estimated partial net return was $6.31/m 2 Convtl x YW plants produced a mean marketable yield of 2.91 kg/m 2 and at that yield for the mean conventional greenhou se

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134 grown red bell pepper price of $27.75/5 kg carton, the estimated partial net return was $13.09/m 2 Convtl x YW treatment achieved a higher partial net return than Convtl x NC because it produced greater yields and incurred lower nutrient management cost s. Gran Gran x PL plants produced a mean marketable yield of 0.90 kg/m 2 and at that yield for the mean organic greenhouse grown red bell pepper price of $43.75/5 kg carton, the estimated partial net return was $5.59/m 2 which is $0.72/m 2 and $7.50 /m 2 less than the partial net return of the Convtl x NC and Convtl x YW treatments, respectively. Gran Soln x PL plants produced a mean marketable yield of 2.45 kg/m 2 and at that yield for the mean organic greenhouse grown red bell pepper price of $ 43.75 /5 kg car ton, the estimated partial net return was $1 8.48 /m 2 which is $ 12.17 /m 2 and $5.39 /m 2 more than the partial net return of the Convtl x NC and Convtl x YW treatments, respectively. Gran Soln x PL nutrient management input cost of $2.94/m 2 was slightly higher than that of Gran Gran x PL at $2.31/m 2 however the significantly higher yield of the Gran Soln x PL treatment offset this extra cost and resulted in a partial net return substantially higher than that of Gran Gran x PL. Although the nutrient management input cost of the Gran Gran x PL treatment was lower than that of the Convtl x NC and Convtl x YW treatments (by 35 and 25%, respectively) and the average market price was higher (by 58 %) the yield achieved by the organic treatment was too low compared to the yield achieved by the conventional treatments (by 49 and 69%, respectively) resulting in a 11 and 57 %, respectively, decrease in partial net return for the organic treatment compared to the conventional treatments. Although there were higher yielding organic treatments in the Spring 2011 experiment, this one was included in the Spring 2011 sensitivity analysis to show how drastically conditions

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135 can change from season to season, and how important it is for growers to be aware of this before attempting organic greenhouse production of bell pepper. On the other hand, the yield achieved by the Gran Soln x PL treatment was higher than the yield achieved by the Convtl x NC treatment (by 38%) and lower than the yield achieved by the Convtl x YW treatment (by 16% ) However, the lower nutrient management input cost of the organic treatment compared to the conventional treatments (by 18 and 5%, respectively) and the higher average market price (by 58 %) resulted in a 193 and 4 1 %, respectively, increase in partial net return for the organic treatment compared to the conventional treatments. Because of the late transplant date (early March instead of January or early February) and the unavoidable greenhouse management problems that occurred in Spring 2011 that contri buted to the overall yield decreases of both conventional and organic nutrient management treatments, Fall 2010 is probably a more representative season to base the economic analyses off of. However, delays and unforeseen problems will always occur in agri culture and the lessons to be taken away from the Spring 2011 economic analyses are no less important. A full economic analysis was performed on indeterminate colored bell pepper conventionally grown in the same greenhouse structure used in this study by J ovicich et al ( 2005 ) Under similar crop management practices and market prices for red conventionally grown greenhouse bell pepper fruit, the study estimated that fruit yields should be greater than 7.8 kg/m 2 in order to generate positive returns to mana gement. The indeterminate nature of the plants used in that study cause d them to grow very tall and continually produce fruit for 6 7 months out of the 10 month long crop season (from seeding to plant removal) The determinate nature of the plants used in my study

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136 means that they grow only to a height of about 3 feet and produce f ruit for only 2 3 harvests at the end of the 5 month long crop season (from seeding to plant removal) resulting in lower season yields compared to indeterminate plants Determinat e plants were chosen for this study because they are, by nature of their size, less demanding than indeterminate plants and so may be more suitable for organic nutrient management systems in which nutrients have to be transformed before they become plant a vailable. Also, clogging of the hydroponic greenhouse fertigation systems by organic nutrient sources worsens with time, so using a determinate variety creates shorter crop seasons (and less liability) between which the fertigation lines can be thoroughly cleaned and reused for the next crop season. As a result, a greenhouse growe r could potentially produce three determinate bell pepper crops per year corresponding to spring, summer and f all. Based on the yields achieved in the Fall 2010 and Spring 2011 t rials of my organic greenhouse study (and averaging the Fall and Spring yields for an estimate of what a summer crop yield would be), the Gran Gran x PL nutrient management strategy would result in an average yearly marketable yield of 4.86 kg/m 2 and a max imum yearly marketable yield of 6.59 kg/m 2 The Gran Soln x PL nutrient management strategy would result in an average yearly marketable yield of 7.23 kg/m 2 and a maximum yearly marketable yield of 10.08 kg/m 2 Other factors to consider are: The delayed tr ansplanting, electrical issues and irrigation system clogging that negatively affected yield in th e Spring 2011 trial highlights the fact that as the system is modified and improved over the years, yields will increase, thereby increasing gross revenue. Re search has cited that it can take up to 5 years after transition to organic farming for growers to reach and maintain their top organic production level ( U.S. Dept. of Agriculture, 2009b ).

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137 Prices are significantly higher for organic greenhouse grown red be ll pepper compared to conventional which would result in higher gross revenue ( U.S. Dept. of Agriculture, 2012a ) P roduction costs may be less for determinate plants compared to indeterminate because they are significantly shorter (e.g. trellis accessories labor, yearly fertilizer and water quantities, etc.) The l ower n utrient management costs associated with these organic treatments (as demonstrated in Table 3 2) could be factored in. The costs of pesticides would not be included because pesticides are p rohibited in organic production. Certain materials like pots, media, and irrigation lines would be re used across crop seasons in the year. With all these factors considered in how the organic nutrient management treatments used in my study would affect th e full economic analysis of greenhouse grown red bell pepper performed by Jovicich et al (2005) it would be understandable to extrapolate and conclude that organic greenhouse gr own red bell pepper operations c ould be profitable. However a full economic a nalysis must be performed or the above changes made to the analysis performed by Jovicich et al (2005) in order to fully explore this hypothesis. Also different greenhouse operations vary considerably in their size, technology and infrastructure, all of w hich would significantly affect total costs and yields and the potential profitability of organic greenhouse colored bell pepper operations, therefore greenhouse growers should use this information only as a guide and calculate the budgets for their own en terprises Some research suggests that 50% of the applied nitrogen in organic nutrient sources is made available in a given season. As a result, organic production guidelines often suggest applying organic nitrogen at a rate two times that of conventional inorganic nitrogen However, this was not done in this study because it was important to

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138 keep applied nutrient (especially nitrogen) levels consistent across treatments for comparison purposes (in both the production and economic analysis studies), and als o because other research has shown higher disease incidence and leachate/substrate EC (and therefore lower marketable yields) from higher organic fertilizer rates ( Miles and Peet, 2002 ; Rippy et al, 2004 ; Zhai et al., 2009 ). It was also important to keep o rganic nutrient management input costs down to help ensure positive partial net returns in the subsequent economic analysis. Conclusions As demand for and price premiums associated with colored, greenhouse grown and organic fresh market bell pepper increas e, combining these aspects into a successful organic greenhouse grown red bell pepper operation presents itself as a potentially lucrative market niche for growers to expand into Although only a fraction of applied organic nitrogen becomes available durin g the season and organic yields tend to be lower than conventional yields, this study demonstrates that by keeping organic fertilizer rates consistent with typical conventional hydroponic fertilizer rates, locally sourcing relatively inexpensive organic nu trient /media sources and adjusting application strategies the yield reduction could potentially be offset by lower nutrient management input costs and substantially higher market prices of organic compared to conventional greenhouse produce, resulting in potentially higher organic partial net returns. Since red bell pepper market prices tend to be highest in December and May (Cantliffe et al., 2008) it will be important for growers to time their growing season to capture these highest market prices. Howev er, the economic viability of organic greenhouse grown red bell pepper production will ultimately depend on types and amounts of organic nutrient/media sources available to a specific grower, the type of cultivar chosen (e.g.

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139 determinate vs. indeterminate) and the specific greenhouse size, technology and infrastructure (which will affect both yields and production costs). Therefore, full cost benefit analysis will be essential for individual growers to gauge the profitability and feasibility of such an ent erprise. Future research could also focus on implementing greenhouse technologies that can contribute to organic production and in the long run reduce nutrient management and energy costs. For example, the technology exists for composting greenhouses, in w hich the heat and carbon dioxide generated from manure based compost contained in a chamber attached to one side of the greenhouse can be used to heat the greenhouse during the winter months when needed (Greer and Diver, 2000). This would cut down on energ y costs, prepare and provide poultry litter compost for incorporation into the media mixes of the next organic greenho use crop season, and take advan tage of local resources.

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140 Table 3 1 Sourc es and prices for nutrient management materials used in greenhou se production of conventional and organic red bell peppers Item Source Description Unit Price ($/unit) z Fertilizers Calcium nitrate Chemical Dynamics, FL Ca(NO 3 ) 2 1 gal 5.15 DynaPhos phosphoric acid Chemical Dynamics, FL H 3 PO 4 1 gal 13.50 Potassium chloride Chemical Dynamics, FL KCl 1 ton 870 Epsom magnesium sulfate Giles Chemical, NC MgSO 4 50 lb 15.50 Sequestrene c helated iron Southern Ag, FL FE 330 5 lb 36.35 Copp er sulfate Southern Ag, FL CuSO 4 50 lb 92.50 Manganese sulfate Southern Ag, FL MnSO 4 50 lb 30 Zinc sulfate Hi Yield FL ZnSO 4 50 lb 38.75 Solubor boron Southern States FL B 50 lb 38 Sodium molibdate Southern Ag, FL Na 2 (MoO 4 ) 4 oz 5.60 Ag Life 2 4 2 O C Rhizogen, TX Composted poultry manure (granular) 1 ton 405 Blending Base Fertilizer 13 0 0 Nature Safe, KY Hydrolyzed feather meal, meat meal and blood meal (pelleted) 1 ton 712 Allganic p otassium sulfate 0 0 51 SQM, GA K 2 SO 4 (granular) 1 ton 740 Cal CM Plus calcium sulfate MP Art Wilson Co, NV Anhydrite CaSO 4 (granular) 1 ton 182 HFPC spr ay dried hydrolyzed fish protein California Spra y Dry Co, CA Fresh fish or fish frames from filleting plants (fine powder) 40 lb 68 Allganic p otassium sulf ate 0 0 52 SQM, GA K 2 SO 4 (crystalline, water soluble) 1 ton 670 Cal CM Plus calcium sulfate SG Art Wilson Co, NV Anhydrite CaSO 4 (solution grade) 1 ton 106 Media Sunshine peat moss SunGro Horticulture FL Peat; soilless substrate 1 cu yd 86 Pine ba rk Elixson Wood Products, FL Pine bark; soilless substrate 1 cu yd 8.25 Poultry litter compost Hoovers Organic Farm, FL Animal based compost 1 cu yd 10 Yard waste compost Gainesville Wood Resource and Recovery, FL Plant based compost 1 cu yd 15 Equipmen t MiniDos 2.5% y Dosmatic U.S.A., TX Fertilizer proportional injector 1 275 z Based on Fall 2010 prices. y A straight line depreciation was applied for five expected years of use.

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141 Table 3 2 Nutrient management costs in greenhouse production of determ inate red bell pepper plants under two conventional and two organic fertilizer and media treatments Spring 2011 Per 1000 plants z,y Convtl x NC Convtl x YW Gran Gran x PL Gran S oln x PL Item Amount Cost ($) A mount Cost ($) Amount Cost ($) Amount Cost ($) Fertilizers Calcium nitrate 78.32 L 106.55 78.32 L 106.55 DynaPhos phosphoric acid 9.80 L 34.97 9.80 L 34.97 Potassium chloride 25.95 kg 24.89 25.95 kg 24.89 Epsom magnesium sulfate 34.24 kg 23.40 34.24 kg 23.40 Sequestrene c helated iron 2.19 kg 35.03 2.19 kg 35.03 Copper sulfate 0.06 kg 0.23 0.06 kg 0.23 Manganese sulfate 0.19 kg 0.26 0.19 kg 0.26 Zinc sulfate 0.06 kg 0.10 0.06 kg 0.10 Solubor boron 0.24 kg 0.40 0 .24 kg 0.40 Sodium molibdate 0.01 kg 0.53 0.01 kg 0.53 Ag Life 2 4 2 OC 199.59 kg 89.11 155.81 kg 69.56 Blending Base Fertilizer 13 0 0 47.91 kg 37.60 15.36 kg 12.06 Allganic p otassium sulfate 0 0 51 23.75 kg 19.37 9.66 kg 7.88 Ca l CM Plus calcium sulfate MP 3.14 kg 0.63 HFPC spr ay dried hydrolyzed fish protein 47.75 kg 178.94 Allganic p otassium sulfate 0 0 52 14.32 kg 10.58 Cal CM Plus calcium sulfate SG 10.95 kg 1.28 Media Sunshine peat moss 6 .61 m 3 743.22 4.63 m 3 520.25 4.63 m 3 520.25 4.63 m 3 520.25 Pine bark 6.61 m 3 71.30 4.63 m 3 49.91 4.63 m 3 49.91 4.63 m 3 49.91 Poultry litter compost 3.96 m 3 51.85 3.96 m 3 51.85 Yard waste compost 3.96 m 3 77.78 Equipment MiniDos 2.5% x 5.56 152.78 5.56 152.78 2.78 76.39 Total cost/1000 plants 1193.65 1027.07 768.72 978.70 Total cost/plant 1.19 1.03 0.77 0.98 Total cost/m 2 w 3.58 3.08 2.31 2.94 z Estimates of amounts based on one 4 month determinate bell pepper crop and c osts based on Fall 2010 prices for 1000 plants.

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142 y Fertilizer x Compost treatment combinations. Fertilizer treatments: Convtl = conventional mineral based solution injected through irrigation system t hroughout the season; Gran Gran = organic granular incorpo rated into media at transpl anting and sidedress; Gran Soln = organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning a t sidedress Total season application of N, P, K, Ca and water were co nsistent across all treatments. Compost treatments: NC = no compost; YW = 30% y ard waste compost by volume; PL = 30% poultry litter compost by volume. All have a media base of 1 peat : 1 pine bark (by volume). x One MiniDos 2.5% fertilizer proportional inje ct or has a 45 L/min flow rate and can service 360 plants fed by 7.6 L/ h emitters. A straight line depreciation was applied for five expected years of use. w Based on a plant density of 3 plants/m 2

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143 T abl e 3 3 Estimated partial net return for yields of d eterminate red bell pepper plants grown with conventional fertilizer and two different compost treatments in a saw Estimated partial net return ($/m 2 ) y Standard Yield z Red greenhouse gro wn bell pepper price ($/5 kg carton) x Error ( kg/m 2 ) 15.75 18.75 21.75 24.75 w 27.75 30.75 33.75 Convtl x NC v 3 3.05 6.02 7.85 9.68 11.51 13.34 15.17 17.00 2 3.19 6.48 8.40 10.32 12.23 14.15 16.07 17.99 1 3.34 6.94 8.95 10.95 12.96 14.96 16.97 18. 97 Mean 3.49 7.40 9.49 11.59 13.68 15.77 17.86 19.95 +1 3.63 7.86 10.04 12.22 14.40 16.58 18.76 20.94 +2 3.78 8.32 10.59 12.86 15.12 17.39 19.66 21.92 +3 3.92 8.78 11.14 13.49 15.84 18.20 20.55 22.91 Convtl x YW v 3 3.08 6.61 8.45 10.30 1 2.14 13.99 15.83 17.68 2 3.39 7.59 9.63 11.66 13.69 15.72 17.76 19.79 1 3.70 8.58 10.80 13.02 15.24 17.46 19.68 21.90 Mean 4.01 9.56 11.97 14.38 16.79 19.20 21.61 24.02 +1 4.33 10.55 13.15 15.74 18.34 20.94 23.53 26.13 +2 4.64 11.54 14.32 17.10 19.8 9 22.67 25.46 28.24 +3 4.95 12.52 15.49 18.47 21.44 24.41 27.38 30.35 z Yields presented were the estimated mean marketable yield 3 standard errors; the estimated mean marketable yield was based on data from the Fall 2010 experimental greenhouse trials. Plant density = 3 plants/m 2 y Matrix values represent [(yield x $/kg) nutrient management cost]. Other production, harvest, and packing costs (e.g. site preparation, greenhouse structure, irrigation and climate control systems, electrical and drainage s ystems, growing cont ainers, trellis accessories, IPM materials, pollinators, energy, packing cartons, labor, etc.) must be factored in to achieve a full net return. x Prices per kg were calculated from published w eekly average wholesale market prices for tr ansactions of 5 kg cartons of imported, conventional greenhouse grown red bell peppers at the Atlanta terminal market during December and over the year period 2004 2 011 (U.S. Department of Agricult ure, Fruit and Vegetable Market News Portal). w Mean for th e collected price data. v Fertilizer x Compost treatment combinations. Convtl fertilizer treatment = conventional mineral based solution injected through irrigation system t hroughout the season (t otal season application of N, P, K, Ca and water were consist ent across all treatments ) Compost treatments have a media base of 1 peat : 1 pine bark (by volume) with NC = no compost, and YW = 30% y a rd waste compost by volume.

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144 Table 3 4 Estimated partial net return for yields of determinate red bell pepper plants grown with two different organic fertilizer treatments and one compost treatment in a saw Fall 2010 Estimated partial net return ($/m 2 ) y Standard Yield z Red greenhouse grown bell pepper price ($/ 5 kg carton) x Error ( kg/m 2 ) 29.50 34.00 38.50 43.00 w 47.50 52.00 56.50 Gran Gran x PL v 3 1.89 8.81 10.51 12.21 13.91 15.60 17.30 19.00 2 2.04 9.70 11.54 13.37 15.20 17.03 18.87 20.70 1 2.19 10.59 12.56 14.53 16.50 18.46 20.43 22.40 Mean 2.34 11 .48 13.58 15.69 17.79 19.89 22.00 24.10 +1 2.49 12.37 14.61 16.85 19.08 21.32 23.56 25.80 +2 2.64 13.26 15.63 18.00 20.38 22.75 25.13 27.50 +3 2.79 14.14 16.65 19.16 21.67 24.18 26.69 29.20 Gran Soln x PL v 3 1.47 5.71 7.02 8.34 9.66 10.98 12.30 13.62 2 1.77 7.49 9.08 10.67 12.26 13.85 15.44 17.03 1 2.07 9.27 11.13 13.00 14.86 16.72 18.58 20.45 Mean 2.37 11.05 13.19 15.32 17.46 19.59 21.73 23.86 +1 2.67 12.84 15.24 17.65 20.05 22.46 24.87 27.27 +2 2.98 14.62 17.30 19.97 22.65 25.33 2 8.01 30.69 +3 3.28 16.40 19.35 22.30 25.25 28.20 31.15 34.10 z Yields presented were the estimated mean marketable yield 3 standard errors; the estimated mean marketable yield was based on data from the Fall 2010 experimental greenhouse trials. Plant de nsity = 3 plants/m 2 y Matrix values represent [(yield x $/kg) nutrient management cost]. Other production, harvest, and packing costs (e.g. site preparation, greenhouse structure, irrigation and climate control systems, electrical and drainage systems, g rowing cont ainers, trellis accessories, IPM materials, pollinators, energy, packing cartons, labor, etc.) must be factored in to achieve a full net return. x Prices per kg were calculated from published weekly average wholesale market prices for transaction s of 5 kg cartons of imported, organic greenhouse grown, red bell peppers at the Atlanta Boston, Chicago and Philadelphia terminal market s during December and over the year period 2004 2 011 (U.S. Department of Agricult ure, Fruit and Vegetable Market News Portal). w Mean for the collected price data. v Fertilizer x Compost treatment combinations. Gran Gran fertilizer treatment = organic granular incorporated into media at transpl anting and sidedress; Gran Soln fertilizer treatment = organic granular incorpora ted into media at transplanting and organic solution injected through irrigation system beginning at sidedress ; (t otal season application of N, P, K, Ca and water were consistent across all treatments ). PL compost treatment = a media base of 1 peat : 1 pin e bark (by volume) with 30% poultry litter compost by volume.

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145 Table 3 5 Estimated partial net return for yields of determinate red bell pepper plants grown with conventional fertilizer and two different compost treatments in a saw tooth style greenhouse Estimated partial net return ($/m 2 ) y Standard Yield z Red greenhouse grown bell pepper price ($/5 kg carton) x Error ( kg/m 2 ) 15.75 19.75 23.75 27.75 w 31.75 35.75 39.75 Convtl x NC v 3 1.24 0.32 1.31 2.2 9 3.28 4.27 5.26 6.25 2 1.42 0.89 2.02 3.16 4.29 5.43 6.56 7.70 1 1.60 1.46 2.74 4.02 5.30 6.58 7.86 9.14 Mean 1.78 2.03 3.46 4.89 6.31 7.74 9.16 10.59 +1 1.96 2.61 4.18 5.75 7.32 8.89 10.46 12.03 +2 2.15 3.18 4.90 6.61 8.33 10.05 11.76 13.48 +3 2. 33 3.75 5.61 7.48 9.34 11.20 13.06 14.92 Convtl x YW v 3 0.71 0.83 0.26 0.32 0.89 1.46 2.03 2.60 2 1.45 1.48 2.64 3.80 4.95 6.11 7.27 8.43 1 2.18 3.79 5.53 7.28 9.02 10.76 12.51 14.25 Mean 2.91 6.10 8.43 10.76 13.09 15.42 17.75 20.08 +1 3.65 8.40 11.32 14.24 17.15 20.07 22.99 25.90 +2 4.38 10.71 14.21 17.72 21.22 24.72 28.22 31.73 +3 5.11 13.02 17.11 21.20 25.29 29.37 33.46 37.55 z Yields presented were the estimated mean marketable yield 3 standard errors; the estimated mean marke table yield was based on data from the Spring 2011 experimental greenhouse trials. Plant density = 3 plants/m 2 y Matrix values represent [(yield x $/kg) nutrient management cost]. Other production, harvest, and packing costs (e.g. site preparation, green house structure, irrigation and climate control systems, electrical and drainage systems, growing containers, trellis accessories, IPM materials, pollinators, energy, packing cartons, labor, etc.) must be factored in to achieve a full net return. x Prices p er kg were calculated from published weekly average wholesale market prices for transactions of 5 kg cartons of imported, conventional greenhouse grown, red bell peppers at the Atlanta terminal market during May and over the year period 2004 2012 (U.S. Dep artment of Agriculture, Fruit and Vegetable Market News Portal). w Mean for the collected price data. v Fertilizer x Compost treatment combinations. Convtl fertilizer treatment = conventional mineral based solution injected through irrigation system t hrougho ut the season (t otal season application of N, P, K, Ca and water were consistent across all treatments ). Compost treatments have a media base of 1 peat : 1 pine bark (by volume) with NC = no compost, and YW = 30% y ard waste compost by volume.

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146 Table 3 6 Estimated partial net return for yields of determinate red bell pepper plants grown with two different organic fertilizer treatments and one compost treatment in a saw Spring 2011 Estimated partial net return ($/m 2 ) y Standard Yield z Red greenhouse grown bell pepper price ($/5 kg carton) x Error ( kg/m 2 ) 34.75 37.75 40.75 43.75 w 46.75 49.75 52.75 Gran Gran x PL v 3 0.21 0.85 0.72 0.60 0.47 0.35 0.22 0.09 2 0.44 0.76 1.02 1.29 1.55 1.81 2.08 2.34 1 0.67 2.36 2.77 3.17 3.57 3.98 4.38 4.78 Mean 0.90 3.97 4.51 5.05 5.59 6.14 6.68 7.22 +1 1.13 5.57 6.26 6.94 7.62 8.30 8.98 9.66 +2 1.37 7.18 8.00 8.82 9.64 10.46 11.28 12.10 +3 1.60 8.79 9.75 10.70 11.66 12.62 13.58 14.54 Gra n Soln x PL v 3 1.46 7.18 8.06 8.93 9.80 10.68 11.55 12.43 2 1.79 9.48 10.55 11.62 12.70 13.77 14.84 15.91 1 2.12 11.78 13.05 14.32 15.59 16.86 18.13 19.40 Mean 2.45 14.07 15.54 17.01 18.48 19.95 21.41 22.88 +1 2.78 16.37 18.03 19.70 21.37 23.03 24. 70 26.37 +2 3.11 18.66 20.53 22.39 24.26 26.12 27.99 29.85 +3 3.44 20.96 23.02 25.09 27.15 29.21 31.27 33.34 z Yields presented were the estimated mean marketable yield 3 standard errors; the estimated mean marketable yield was based on data from the S pring 2011 experimental greenhouse trials. Plant density = 3 plants/m 2 y Matrix values represent [(yield x $/kg) nutrient management cost]. Other production, harvest, and packing costs (e.g. site preparation, greenhouse structure, irrigation and climate control systems, electrical and drainage systems, growing containers, trellis accessories, IPM materials, pollinators, energy, packing cartons, labor, etc.) must be factored in to achieve a full net return. x Prices per kg were calculated from published wee kly average wholesale market prices for transactions of 5 kg cartons of imported, organic greenhouse grown, red bell peppers at the Atlanta, Boston, Chicago and Philadelphia terminal markets during May and over the year period 2005 2 012 (U.S. Department of Agriculture, Fruit and Vegetable Market News Portal). w Mean for the collected price data. v Fertilizer x Compost treatment combinations. Gran Gran fertilizer treatment = organic granular incorporated into media at transpl anting and sidedress; Gran Soln fer tilizer treatment = organic granular incorporated into media at transplanting and organic solution injected through irrigation system beginning at sidedress ; (t otal season application of N, P, K, Ca and water were consistent across all treatments ). PL comp ost treatment = a media base of 1 peat : 1 pine bark (by volume) with 30% poultry litter compost by volume.

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147 CHAPTER 4 CONCLUSIONS AND SUMM ARY Peat and pine bark substrate amended with poultry litter compost and fertilized with all granular or either com bination of organic granular and nutrient solution sources produced the highest organic greenhouse marketable red bell pepper yields of 57 138% of the hydroponic control. Because different organic nutrient fertilizers and media/composts vary considerably i n their properties and rates of nutrient availability, using multiple sources of organic nutrients and a combination of incorporated, top dressed and fertigated fertilization systems may increase the size, biodiversity and activity of the microbial populat ions in the media, thereby influencing the physical, chemical and biological characteristics of the media that govern plant health as well as nitrification/mineralization activities and, therefore, yield ( Chang et al., 2007 ; Greer and Diver, 2000 ; Treadwel l et al., 2007; Zhai et al., 2009 ). In my study, organic granular fertilizer treatments consisted of four different products, and organic solution fertilizer treatments consisted of three different products, for a total of seven different organic nutrient sources applied to the Gran Soln or Soln Gran fertilizer treatments. Since organic fertilizers delivered hy d roponically tend to clog the irrigation system, it may be best to not use them at all (Gran Gran treatment) or delay their use for the first 30 days and then fertigate with them at low concentration (Gran Soln treatment). Incorporating half of total season nutrients via granular organic fertilizers into the media at transplant avoids excessive EC and allows the plants to derive their nutrients from gr anular sources until 30 days after transplant, at which time the rest of total season nutrients can be supplied by an organic granular sidedress or a dilute organic nutrient solution delivered through the irrigation system regularly until harvest.

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148 Poultry litter compost is more effective than yard waste compost for organic greenhouse bell pepper production because it has lower pH, higher EC, more temperature buffering capacity, higher water holding capacity, lower C:N ratio, higher micronutrient concentrati ons and possibly more active nitrifying/mineralizing microorganism populations as evidenced by the higher leachate [NO 3 N] and fruit percent NUE. As a result, the media treatment containing poultry litter compost (PL) resulted in higher yields, taller plan ts throughout the season and greater whole plant dry weight at harvest compared to the media treatments containing no compost or yard waste compost. However, it is important to keep water availability consistent because the high sodium, potassium and solub le salt levels in poultry litter compost can lead to higher than optimal EC and salt salinity stress under water deficiency, resulting in higher blossom end rot incidence and lower yields. Also, the phosphorus content in poultry litter compost could potent ially limit Ca availability through precipitation reactions, leading to blossom end rot, so effective calcium supplementation via fertilizers must be utilized to avoid this problem. On the other hand, because the poultry litter compost increased the water holding capacity of the media to 90%, it is important to not over irrigate, reducing the oxygen filled pore spaces that are necessary for nitrification reactions (Evanylo and McGuinn, 2009). For future research, it would also be interesting to apply this e xperiment to an indeterminate bell pepper cultivar, which is typically used in greenhouse production systems and has a crop season of 10 months. Although the organic nutrient solution in low concentration did fairly well, there were still clogging problems and so a future study could look at exploring a variety of different organic nutrient sources to make into

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149 fertigation solution and assess their clogging potential. Also, future research could attempt to acidify the organic nutrient solution with citric acid or other OMRI approved acidifying agent to help solubilize the materials and decrease the pH in the media of the organic treatments. As demand for and price premiums associated with colored, greenhouse grown and organic fresh market bell pepper increa se, combining these aspects into a successful organic greenhouse grown red bell pepper operation presents itself as a potentially lucrative market niche for growers to expand into Although only a fraction of applied organic nitrogen becomes available duri ng the season and organic yields tend to be lower than conventional yields, this study demonstrates that by keeping organic fertilizer rates consistent with typical conventional hydroponic fertilizer rates, locally sourcing relatively inexpensive organic n utrient/media sources and adjusting application strategies, the yie ld reduction could potentially be offset by lower nutrient management input costs and substantially higher market prices of organic compared to conventional greenhouse produce, resulting in potentially higher organic partial net returns. Since red bell pepper market prices tend to be highest in December and May (Cantliffe et al., 2008), it will be important for growers to time their growing season to capture these highest market prices. Howe ver, the economic viability of organic greenhouse grown red bell pepper production will ultimately depend on types and amounts of organic nutrient/media sources available to a specific grower, the type of cultivar chosen (e.g. determinate vs. indeterminate ), and the specific greenhouse size, technology and infrastructure (which will affect both yields and production costs). Therefore, full cost benefit analysis will be essential for individual growers to gauge the profitability and

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150 feasibility of such an en terprise Future research could also focus on implementing greenhouse technologies that can contribute to organic production and in the long run reduce nutrient management and energy costs. For example, the technology exists for composting greenhouses, in which the heat and carbon dioxide generated from manure based compost contained in a chamber attached to one side of the greenhouse can be used to heat the greenhouse during the winter months when needed (Greer and Diver, 2000). This would cut down on ener gy costs, prepare and provide poultry litter compost for incorporation into the media mixes of the next organic greenho use crop season, and take advan tage of local resources. T here is potential for organic greenhouse production of fresh market colored bell pepper to be successful for Florida growers, both in terms of yield and economic viability. However, the breadth of research on this topic needs to expand and new technologies, products and practices must be developed in order to improve organic yields, r educe costs of gr eenhouse production, and, eventually, render organic greenhouse production of colored bell pepper an economically and environmentally sustainable and well established enterprise for U.S. growers.

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151 LIST OF REFERENCES Barrett, C.E., X. Zhao and A.W. Hodges. 2012. Cost benefit analysis of using grafted transplants for root knot nematode management in organic heirloom tomato production. HortTechnology 22(2):1 6. Bar Tal, A., M. Keinan, S. Fishman, B. Aloni, Y. Oserovitz, and M. Genard. 1999. Simulation of environmental effects on Ca content in pepper fruit. Acta Hort. 507:253 262. Bulluck III., L R M Brosius G.K. Evanylo, and J.B. Ristaino 2002. Organic and synthetic fertility amendments influence soil microbial, physical and chemical pr operties on organic and conventional farms. Appl. Soil E col. 19: 147 160. Cantliffe, D.J., J.E. Webb, J.J. VanSickle, and N.L. Shaw. 2008. Increased net profits result from greenhouse grown colored peppers compared to field production in Florida Proc. Fla. State Hort. Soc. 121:194 200. Celi k I., I. Ortas, and S. Kilic. 2004. Effect of compost, mycorrhiza, manure and fertilizer on some physical properties of Chromoxerert soil. Soil Till. Res. 78:59 67. Chang, E. H., R. S. Chung, and Y. H. Tsai. 2007. Effect of different application rates of organic fertilizer on soil enzyme activity and microbial population. Soil Sci. Plant Nutr. 53:132 140. Cruz Huerta, N 2010. Temperature effects on o vary swelling in sweet pepper: P hysiology and anatomy. Univ. of Florida, Gainesville ,PhD Diss d el Amor, F.M. 2007 Yield and fruit quality response of sweet pepper to orga nic and mineral fertilization. Renew. Agr. Food Syst. 22(3): 233 238. d el Amor, F.M. A. Serrano Martinez, I. Fortea, and E. Nunez Delicado. 2008. Differenti al effect of organic cultivation on the levels of phenolics, peroxidase a nd capsidiol in sweet peppers. J. Sci. Food Agr. 88: 770 777. Dodson, M., J. Bachmann, and P. Williams. 2002. Organic greenhouse tomato production. National Center for Approp riate Tech nology (NCAT), ATTRA publication 54 16p. 7 June 2012. < https://attra.ncat.org/attra pub/summaries/summary.php?pub=54 > Evanylo, G. and R. McGuinn. 2009. Agricultural management p ractices and soil quality: measuring, assessing, and comparing laboratory and field test kit indicators of soil quality attributes. Communications and marketing, College of Agriculture and Life Sciences, Virginia Polytechnic Institute and State University. Virginia Cooperativ e Extension Publication 452 400, 9p.

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152 Florida Dept. of Environmental Protection. 2010. services: C ontainers and preservation.28 May 2010. < http://www.dep.state.fl.us/labs/docs/container_preserv.pdf > Greer, L. and S. Diver. 2000. Organic gr eenhouse vegetable production. National Center for Approp riate Technology (NCAT), ATTRA publication 45 19p. 7 June 2012. < https://attra.ncat.org/attra pub/summaries/summary.php?pub=45 > Hartz, T .K., R. Smith, and M. Gaskell. 2010. Nitrogen availability fr om liquid organic fertilizers. HortTechnology 20(1): 169 172 Heeb, A., B. Lundegardh, G. Savage, and T. Ericsson. 2006. Impact of organic and inorganic fertilizers on yield, taste, and nutritional quality of tomatoes. J. Plant Nutr. Soil Sci. 169:535 541. Hochmuth, G.J., D.N. May nard, C. Vavrina, and E. Hanlon. 19 91. Plant tissue a nalysis and interpretation for vegetable c rops in Florida Florida Cooperative Extension Service p ublication SS VEC42, 12 p Jovicich E. and D.J. Cantliffe. 2004. Salts deposited on the lower stem of bell pepper contribute to a basal stem disorder in soilless green house grown plants. HortScience 39(1):36 39. Jovicich, E., D.J. Cantliffe, N.L. Shaw, and S. A Sargent. 2003. Production of greenh ouse grown peppers in Florida. Citrus and Vegetable Mag azine 67:G 7 12 Jovicich, E., D.J. Cantliffe and P.J. Stoffella. 2004. Fruit yield and quality of greenhouse grown bell pepper as influenced by density, container, and trellis system. HortTechnology 14(4): 507 513. Jovi cich, E., D.J. Cantliffe, P.J. Stoffella, and D.Z. Haman. 2007. Bell pepper fruit yield and quality as influenced by solar ratdiation based irrigation and container media in a pa ssively ventilated greenhouse. HortScience 42(3): 642 652. Jovicich, E. J.J. VanSickle, D.J. Cantliffe and P.J. Stoffella. 2005. Greenhouse grown colored pepp ers: a profitable alternative for ve getable production in Florida? HortTechnology 15(2): 355 369. Kelley, T W. and G. E. Boyhan. 2009. Commercial p epper production h andbook. The University of Georgia Cooperative Extension Bulletin 1309, 45p. 6 July 2012 < http://www.caes.uga.edu/publications/pubdetail.cfm?pk_id=7461 > Kokalis Burelle Kabana, C.S. Vavrina, E.N. Rosskopf and D.S. Kenney. 1999. Evaluation of amended transplant mixes for fruit and vegetable production. Proc Annual International Research Conference on Methyl Bromide Alternatives and Emiss ions Reductions, p. 83.1 83.2 18 Jan. 2000. < http://mbao.org/1999airc/83burell.pdf >

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153 Kraus, H.T. and S.L. Warren. 2000. Performance of turkey litter compost as a slow release fertilizer in containerized p lant production. HortScience 35:19 21. Kuepper, G. and K. Everett. 2004. Potting mixes for certified organic production. National Center for Appropriate Techno logy (NCAT), ATTRA publication 47 20p. 7 June 2012. < https://attra.ncat.org/attra pub/summaries/summary.php?pub=47 > Lee, J.J., R.D. Park, Y.W. Kim, J.H. Shim, D.H. Chae, Y.S. Rim, B.K. Sohn, T.H. Kim, and K.Y. Kim. 2004. Effect of food waste compost on microbial populations soil enzyme activity and lettuce growth. Bioresour. Technol. 93:21 28. Marcelis, L. and L.C. Ho. 1999. Blossom end rot in relation to growth and calcium content in fruit of sweet pepper ( Capsicum annuum L.). J. Expt. Bot. 50:357 363. Marinari, S., G. Mas ciandaro, B. Ceccanti, and S. Grego. 2000. Influece of organic and mineral fertilisers on soil biological and physical properties. Bioresour. Technol. 72:9 17. Martinez, V., F.M. d el Amor, and L.F.M. Marcelis 2005 Growth and physiological response of tom ato plants to different periods of nitrogen sta rvation and recovery. J. Hort. Sci. Biotechnol. 80:147 153. Miles, J.A. and M.M. Peet. 2002. Maintaining nutrient balances in systems utilizing soluble organic fertilizers. Horticultural Sciences Department, N orth Carolina State University, Organic Farming Res. Fou ndation Project Rpt. 23 p Mylavarapu, R assurance plan. Environmental water quality l aboratory QA Manual 6: Doc 6 Mylavarapu, R.S. an d E.D. Kennelley. 2002. UF/IFAS extension soil t estin g laboratory (ESTL) analytical procedures and training m anual. Florida Cooperative Extensio n Service p ublication CIR 1248. July 2012. < http://edis.ifas.ufl.ed u/SS312 > Nutrition Business Journal. 2009 U.S. organic food s ales ($Mil) 1997 2010e c hart 22. New Hope Natural Media, Inc., Boulder, CO Olson, S.M. and B. Santos (eds.). 2013. Vegetable production handbook for Florida 2012 2013. Inst. Food Agr. Sci., U niv. of Florida, Gainesville. Organic Materials Review Institute 2010. OMRI products list: A directory of products for organic use, provided by OIA North America. NOP USDA Organic Certification Program. < http://www.omri.or g > Organic Trade Association. 2011. U.S. organic industry overview. Organic industry survey. 26 Jan. 2012. < http://www.ota.com/pics/documents/2011OrganicIndustrySurvey.pdf >

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154 Or tas, I., A. Demirbas, C. A kpinar, M. Simsek, and Z. Kaya. 2009. The effects of organic material and mycorrhizal inoculation on h orticultural seedling quality. UC Davis: The proceedings of the international plant nutrition colloquium XVI. Osborne, L.S ., and J.E. Barrett. 2005. You can bank on it, banker plants can be used to rear natural enemies to help control greenhouse pests. O rnamental Outlook, Sept. 2 005: 26 27. Paul, E. and F.E. Clark. 1996. Soil microbiology and biochemistry. Academic Press, San Diego, CA. Rippy, J.F.M., M.M. Peet, F.J. Louws, P.V. Nelso n, D.B. Orr, and K.A. Sorensen. 2004. Plant development and harvest yields of greenhouse tomatoes i n six organic growing systems. HortScience 39(2): 1 7. et, and F.J. Louws. 2010. An economic analysis of two grafted tomato transplant production systems in the United States. HortTechnology 20(4):794 803. Russo, V.M. 2006. Biological amendment, fertilizer rate, and irrigation frequency for organic bell pepper transplant production. HortScience 41(6): 1402 1407. Saha, K.S. and D.J. Cantliffe. 2009. Utilization of chlorination and soilless media for management of Pythium aphanidermatum (Edson) Fitzp. in greenhouse production of Capsicum annuum L in a closed soil less system. Univ. of Florida, Gainesville,PhD Diss S anchez, E.S. and T.L. Richard. 2009. U sing organic nutrient sources. The Pennsylvania State University, Ag Communications and Marketing publication UJ256, 15 p 13 Mar. 2009. < http://pubs.cas.psu.edu/FreePubs/pdfs/uj256.pdf > Schwankl, L.J. and G. McGourty. 1992. Organic fertilizers can be injected through low volume i rrigation s ystems. California Agriculture, September October: 21 23. Shaw, N. and D.J. Cantliffe. 2002. Brightly colored pepper cultivars for greenhouse production in Florida. Proc. Fla. State Hort. Soc. 115:236 241. Shuler, K.D. 2003. Performance of bell p epper varieties over two seasons in southeast florida, 2000 2002. P roc. Fla. State Hort. Soc. 116: 107 137. Succop, C.E. and S.E. Newman. 2004. Organic fertilization of fresh marke t sweet basil in a greenhouse. HortTechnology 14(2): 235 239.

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155 Treadwell, D.D, G.J. Hochmuth, R.C. Hochmuth, E.H. Simonne, L.L. Davis, W.L. Laughlin, Y. Li, T. Olczyk, R.K. Sprenkel, and L.S. Osborne. 2007. Nutrient management in organic greenhouse herb production: Where are we now? HortTechnology 17(4):461 466. U.S. Dept. of Agricu lture. 2008 a Table 64: World bell and chile peppers, production, 1 990 2007. Econ. Res. Serv., U.S. Dept. Agr Economics, Statistics and Market Information System. United Nations, Food and Agriculture Organization, FAOStat. 5 Nov. 2008. < http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID= 1659 > U.S. Dept. of Agriculture. 2008b. Tables 6 and 7: U.S. bell peppers, production and value of production b y state, 1 960 2007. Econ. Res. Serv., U.S. Dept. Agr Economics, Statistics and Market Information System. Nat l Ag r. Stat. Serv., vegetables annual s ummary. 5 Nov. 2008. < http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID= 1659 > U.S. Dept. of Agriculture. 2008c. Table 10: Certified organic vegetables; acres of tomatoes, lettuce, carrots, mixed vegatables and unclassified vegetables by state, 1997 and 2000 08. Econ. Res. Serv U.S. Dept. Agr 24 Sept. 2010. < http://www.ers.usda.gov/data products/organic production.aspx > U.S. Dept. of Agriculture. 2009 a Census of agricult ure, quick stats. Nat l A gr. Stat. Serv., U.S. Dept. Agr 30 June 2010. < http://quickstats.nass.usda.gov/ > U.S. Dept. of Agriculture. 2009b. Marketing U.S. organic foods: Recent trends from farms to c onsume rs. Econ. Res. Serv., U.S. Dept. Agr Economic Information Bulletin Number 58 (by C. Dimitri and L. Oberholtzer), 36p. 7 April 2010. < http://www.ers.usda.gov/p ublications/eib economic information bulletin/eib58.aspx > U.S. Dept. of Agriculture. 2012 a Fruit and Vegetable Market News Portal. Agr. Mktg. Serv U.S. Dept. Agr. 6 July, 2012 < http://marketnews.usda .gov/portal/fv > U.S. Dept. of Agriculture. 2012b. Electronic code of federal regulations. Title 7, Subchapter M: Organic foods production act provisions, Sections 205.1 205.691. U.S. Dept. Agr. 24 July, 2012. < http://ecfr.gpoaccess.gov > Van Delden, A. 2001. Yield and growth components of potato and wheat under organic nitrogen management. Agronomy Journal 93:1370 1385. Zbee tnoff A gro Environmental Consulting. 2006. The North American Greenhouse Vegetable Industry, Farm Credit Canada 6 June 2010. < http://www.fcc fac.ca >

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157 BIOGRAPHICAL SKETCH Allison Beyer was born in 19 82 in Smithtown, Long Island, New York. She received her Bachelor of Arts degree in b iology from Cornell University in December 2005. In October 2007, she began working for the University of Florida as a research assistant and field technician at the resea rch farm in Hastings, F L under Dr. Chad Hutchinson. In 2008, she was promoted to senior statistician, conducting research and reporting on potato variety selection, BMP nitrogen rates, and performance of controlled release fertilizers with a variety of cro ps. In January 2010, she began her graduate studies in the Department of Horticultural Sciences at the University of Florida in Gainesville under advisor Dr. Danielle Treadwell and committee members Dr. Dan Cantliffe and Dr. Michael Gunderson working on n utrient management strategies and economic analysis of organic greenhouse production of red bell pepper.