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Effects of Compost and Tillage on Soils and Nutrient Losses in a Simulated Residential Landscape

Permanent Link: http://ufdc.ufl.edu/UFE0041298/00001

Material Information

Title: Effects of Compost and Tillage on Soils and Nutrient Losses in a Simulated Residential Landscape
Physical Description: 1 online resource (134 p.)
Language: english
Creator: Loper, Shawna
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: compaction, nutrient, soil, urbanization
Soil and Water Science -- Dissertations, Academic -- UF
Genre: Soil and Water Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: EFFECTS OF COMPOST AND TILLAGE ON SOILS AND NUTRIENT LOSSES IN A SIMULATED RESIDENTIAL LANDSCAPE By SHAWNA LOPER December 2009 Chair: Amy L. Shober Major: Soil and Water Science Soil and landscape management practices at new home sites have the potential to negatively impact soil and water quality. Research has shown that soil management practices such as organic amendment additions or tillage can improve the physical and chemical properties of soil. However, it is not known if these management practices can significantly improve soil conditions in urban settings, specifically new residential areas. The objectives of this study were to evaluate soil treatment effects on: 1) selected soil physical and chemical properties, 2) plant growth and quality, and 3) nutrient losses in runoff and leachate from simulated residential landscapes. Six soil management treatments were evaluated with four replications (24 total plots) in mixed landscape (mixed ornamental species and turfgrass) plots that were established on compacted soils in a randomized complete block design. The soil management treatments were as follows: unamended soil, tillage only, aeration only, compost only, compost + tillage, and compost + aeration. Composted dairy manure solids were applied as an organic solid amendment at a rate of 508 m3 ha-1 (25% by volume). Tillage treatments turned the soil to a depth of 10-15 cm. Soil physical and chemical properties, plant growth and quality, plant tissue nutrients, leachate volume and leachate NO3-N, NH4-N and dissolved P were assessed periodically. Applications of compost to soils reduced bulk density and pH and increased soil organic matter, electrical conductivity and concentrations of Mehlich 1 P, K, Ca, and Na. Growth data, with the exception of Raphiolepis indica, indicated more growth for ornamental plant species grown in soils amended with composted dairy manure solids. In most instances, plant quality and tissue nutrient content were higher for plants grown in soils receiving compost. Soil treatments and vegetative cover had no affect on P concentrations in leachate. However, there were soil treatment effects on of NO3 + NO2 and NH4 concentration and load in leachate samples at various times throughout the study, where soil receiving compost leached more than unamended soils. Leachate volumes were higher under ornamentals than turfgrass. As a result, N losses (load and concentration) under ornamental cover often exceeded losses from turf. Losses of NO3 + NO2 were highest during the early weeks of the study, while NH4 losses peaked during the warm season as organic N began to mineralize. Results of our study suggest that the addition of compost to soils can improve soil properties and enhance plant growth in residential landscapes when fill soils are used. In contrast, it appears that shallow tillage and aeration had little effect on soil properties or plant growth and quality. Addition of compost did, however, increase nutrient loads in leachate. This creates concerns that one time application of low C:N ratio organic amendments at a rate of 25-35% by volume to the top six inches of soil may lead to significant N losses. The use of compost as a soil amendment in new residential lawns can be recommended only if the use of inorganic fertilizers is reduced.
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 Shawna Loper.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Shober, Amy L.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0041298:00001

Permanent Link: http://ufdc.ufl.edu/UFE0041298/00001

Material Information

Title: Effects of Compost and Tillage on Soils and Nutrient Losses in a Simulated Residential Landscape
Physical Description: 1 online resource (134 p.)
Language: english
Creator: Loper, Shawna
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: compaction, nutrient, soil, urbanization
Soil and Water Science -- Dissertations, Academic -- UF
Genre: Soil and Water Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: EFFECTS OF COMPOST AND TILLAGE ON SOILS AND NUTRIENT LOSSES IN A SIMULATED RESIDENTIAL LANDSCAPE By SHAWNA LOPER December 2009 Chair: Amy L. Shober Major: Soil and Water Science Soil and landscape management practices at new home sites have the potential to negatively impact soil and water quality. Research has shown that soil management practices such as organic amendment additions or tillage can improve the physical and chemical properties of soil. However, it is not known if these management practices can significantly improve soil conditions in urban settings, specifically new residential areas. The objectives of this study were to evaluate soil treatment effects on: 1) selected soil physical and chemical properties, 2) plant growth and quality, and 3) nutrient losses in runoff and leachate from simulated residential landscapes. Six soil management treatments were evaluated with four replications (24 total plots) in mixed landscape (mixed ornamental species and turfgrass) plots that were established on compacted soils in a randomized complete block design. The soil management treatments were as follows: unamended soil, tillage only, aeration only, compost only, compost + tillage, and compost + aeration. Composted dairy manure solids were applied as an organic solid amendment at a rate of 508 m3 ha-1 (25% by volume). Tillage treatments turned the soil to a depth of 10-15 cm. Soil physical and chemical properties, plant growth and quality, plant tissue nutrients, leachate volume and leachate NO3-N, NH4-N and dissolved P were assessed periodically. Applications of compost to soils reduced bulk density and pH and increased soil organic matter, electrical conductivity and concentrations of Mehlich 1 P, K, Ca, and Na. Growth data, with the exception of Raphiolepis indica, indicated more growth for ornamental plant species grown in soils amended with composted dairy manure solids. In most instances, plant quality and tissue nutrient content were higher for plants grown in soils receiving compost. Soil treatments and vegetative cover had no affect on P concentrations in leachate. However, there were soil treatment effects on of NO3 + NO2 and NH4 concentration and load in leachate samples at various times throughout the study, where soil receiving compost leached more than unamended soils. Leachate volumes were higher under ornamentals than turfgrass. As a result, N losses (load and concentration) under ornamental cover often exceeded losses from turf. Losses of NO3 + NO2 were highest during the early weeks of the study, while NH4 losses peaked during the warm season as organic N began to mineralize. Results of our study suggest that the addition of compost to soils can improve soil properties and enhance plant growth in residential landscapes when fill soils are used. In contrast, it appears that shallow tillage and aeration had little effect on soil properties or plant growth and quality. Addition of compost did, however, increase nutrient loads in leachate. This creates concerns that one time application of low C:N ratio organic amendments at a rate of 25-35% by volume to the top six inches of soil may lead to significant N losses. The use of compost as a soil amendment in new residential lawns can be recommended only if the use of inorganic fertilizers is reduced.
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 Shawna Loper.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Shober, Amy L.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2010-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0041298:00001


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1 EFFECTS OF COMPOST AND TILLAGE ON SOILS AND NUTRIENT LOSSES IN A SIMULATED RESIDENTIAL LANDSCAPE By SHAWNA LOPER A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMEN TS FOR TH E DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2009

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2 2009 Shawna Loper

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3 To my family

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4 ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Amy Shober for her endless guidance and support. I also thank my other committee me mbers, Dr. Craig Stanley and Dr. Geoff Shurberg, who gave a lot of help, support, and patience. I would also like to thank my family.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF TABLES ................................ ................................ ................................ ............ 7 LIST OF FIGURES ................................ ................................ ................................ ........ 10 ABSTRACT ................................ ................................ ................................ ................... 13 CHAPTER 1 LITERATURE REVIEW AND RESEARCH OBJECTIVES ................................ ...... 15 Population Growth and Urbanization ................................ ................................ ...... 15 Home Site Construction and the Residential Landscape ................................ ........ 16 Urbanization and Soil Quality ................................ ................................ .................. 17 Urbanization and Soil Hydrology ................................ ................................ ............. 18 Urbanization, Landscape Management and Water Quality ................................ ..... 20 Urbanization and Plant Quality ................................ ................................ ............... 22 Soil Management Practices ................................ ................................ .................... 25 Tillage ................................ ................................ ................................ ............... 25 Organic Amendments ................................ ................................ ....................... 26 Current Research and Needs ................................ ................................ ................. 28 2 EFFECTS OF TILLAGE AND ORGANIC AMENDMENTS ON SOIL PROPERTIES IN A SIMULATED RESIDENTIAL LANDSCAPE ............................ 30 Introduction ................................ ................................ ................................ ............. 30 Material and Methods ................................ ................................ ............................. 34 Experimental Design ................................ ................................ ........................ 34 Compost and Soil Characterization ................................ ................................ .. 36 Data Analysis ................................ ................................ ................................ ... 38 Results and Discussion ................................ ................................ ........................... 38 Compost and Initial Soil Characterization ................................ ......................... 38 Bulk Density ................................ ................................ ................................ ..... 40 Infiltration ................................ ................................ ................................ .......... 42 Organic Matter ................................ ................................ ................................ .. 43 Soil pH ................................ ................................ ................................ .............. 45 Electrical Conductivity ................................ ................................ ...................... 47 Field Moisture Capacity ................................ ................................ .................... 48 Nutrient Content ................................ ................................ ............................... 49 3 EFFECTS OF SOIL TILLAGE AND ORGANIC AM ENDMENTS ON PLANT GROWTH AND QUALITY IN A SIMULATED RESIDENTIAL LANDSCAPE .......... 54

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6 Introduction ................................ ................................ ................................ ............. 54 Materials and Method ................................ ................................ ............................. 56 Experimental Design ................................ ................................ ........................ 56 Plant Growth and Quality ................................ ................................ .................. 59 Plant Tissue Analysis ................................ ................................ ....................... 60 Data Analysis ................................ ................................ ................................ ... 60 Results ................................ ................................ ................................ .................... 61 Galphimia glauca ................................ ................................ .............................. 61 Raphiolepis indica ................................ ................................ ............................ 67 Ilex cornuta ................................ ................................ ....................... 72 Liriope muscari ................................ ................................ ................................ 78 Stenotaphrum secundatum ................................ ................................ .............. 84 Discussion ................................ ................................ ................................ .............. 89 4 NUTRIENT LEACHING FROM SIMULATED RESIDENTIAL LANDSCAPES AS AFFECTED BY COMPOST AND TILLAGE ................................ ............................ 92 Introduction ................................ ................................ ................................ ............. 92 Materials and Method ................................ ................................ ............................. 95 Experimental Design ................................ ................................ ........................ 95 Leachate Collection and Analysis ................................ ................................ ..... 98 Data Analysis ................................ ................................ ................................ ... 98 Results and Discussion ................................ ................................ ........................... 99 Leachate and Runoff Volume ................................ ................................ ........... 99 Leachate pH and Electrical Conductivity ................................ ........................ 102 Dissolved Phosphorus ................................ ................................ .................... 104 Leachate Nitrate (+ Nitrite) ................................ ................................ ............. 106 Leachate Ammonium ................................ ................................ ..................... 110 5 CONCLUSION S ................................ ................................ ................................ ... 112 APPENDIX A ADDITIONAL SOIL ANALYSIS ................................ ................................ ............. 114 Particle Size Analysis ................................ ................................ ............................ 114 Bulk Density ................................ ................................ ................................ .......... 116 Soil Organic Matter ................................ ................................ ............................... 118 Electrical Conductivity ................................ ................................ ........................... 119 Field Moisture Capacity ................................ ................................ ........................ 120 Mehlich 1 Nutrients ................................ ................................ ............................... 121 LIST OF REFEREN CES ................................ ................................ ............................. 124 BIOGRAPHICAL SKETCH ................................ ................................ .......................... 134

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7 LIST OF TABLES Table page 2 1 Selected chemical prope rties of the composted dairy manure solids applied to simulated residential landscapes as an organic soil amendment. ...................... 39 2 2 Selected initial physical and chemical properties of topsoil fill a nd the native subsoil used in simulated residential landscape plots. ................................ ....... 40 2 3 Bulk density of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals at four sampling dates. ................................ ................................ ................................ .................. 41 2 4 Bulk density of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with St. Augustine turfgrass at four sampling dates. ................................ ................................ ................................ .. 41 2 5 Infiltration rate of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals at five sampling dates. ................................ ................................ ................................ .................. 43 2 6 Infiltration rates of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with St. Augustine turfgrass at three sampling dates. ................................ ................................ ................................ .. 43 2 7 Soil organic matter of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ........................ 45 2 8 Soil pH of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ................................ ........................ 47 2 9 Electrical conductivity of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ........................ 48 2 10 Field moisture capacity of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sa mpling dates. ................................ ........................ 49 2 11 Mehlich I nutrient concentrations (mg kg 1 ) of fill soil samples (0 10 cm) collected from simulated residential landscape plots planted with mixed ornamentals and St. Aug ustine turfgrass at five sampling dates. ....................... 52

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8 3 1 Nutrient content in plant tissue collected from G. glauca grown in sandy fill soils receiving compost, shallow tillage, and/or aeration treatmen ts in simulated residential landscape plots at four sampling dates. ................................ ............ 66 3 2 Nutrient content in plant tissue collected from R. indica grown in sandy soils receiving compost, shallow tillage, an d/or aeration treatments in simulated residential landscape plots at four sampling dates. ................................ ............ 71 3 3 Nutrient content in plant tissue collected from I. cornuta grown in sandy soils receiving comp ost, shallow tillage, and/or aeration treatments in simulated residential landscape plots at four sampling dates. ................................ ............ 77 3 4 Nutrient content in plant tissue collected from L. muscari grown in san dy soils receiving compost, shallow tillage, and/or aeration treatments in simulated residential landscape plots at four sampling dates. ................................ ............ 83 3 5 Nutrient content in plant tissue collected from Stenotaphrum secundatum grown in sandy soils receiving compost, shallow tillage, and/or aeration treatments in simulated landscape plots at four sampling dates. ................................ ......... 88 A 1 Particle size distributi on of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ...................... 115 A 2 Particle size distribution of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ...................... 116 A 3 Bulk density of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals at four sampling dates. ................................ ................................ ................................ ................ 117 A 4 Bulk density of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with St. Augustine turfgrass at five sampling dates. ................................ ................................ ................................ 118 A 5 Soil organic matter of fill soil s amples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ...................... 119 A 6 Electrical conductivity (EC) of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ...................... 120 A 7 Fiel d moisture capacity of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ...................... 120

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9 A 8 Mehlich I nutrient content (mg kg 1 ) of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ..................... 122

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10 LIST OF FIGURES Figure page 2 1 Temporal trends in soil pH of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. ................................ ........................ 47 3 1 Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of G. glauca grown in sandy fill soils receiving compost, shallow ti llage and/or aeration treatments in simulated residential landscape plots. ............................ 62 3 2 Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of G. glauca grown in sandy fill soils receiving com post, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ .......... 63 3 3 Dieback ratings from 0 to 52 weeks after treatment (WAT) of G. glauca grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ............................ 64 3 4 Density ratings from 0 to 52 weeks after treatment (WAT) of G. glauca grown in sand y fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ............................ 65 3 5 Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ............................ 68 3 6 Mean SPAD readings from 0 to 52 weeks after tr eatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ .......... 68 3 7 Dieback ratings from 0 to 52 w eeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ............................ 69 3 8 Density ratings from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ............................ 70 3 9 Mea n canopy growth index from 0 to 52 weeks after treatment (WAT) of I. cornuta and/or aeration treatments in simulated residential landscape plots. ................. 73 3 10 Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ .......... 74

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11 3 11 Dieback ratings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ .......... 75 3 12 Density ratings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential lands cape plots. ................................ .......... 76 3 13 Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in sim ulated residential landscape plots. ............................ 79 3 14 Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillage and/or aeratio n treatments in simulated residential landscape plots. ................................ .......... 80 3 15 Dieback ratings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillag e and/or aeration treatments in simulated residential landscape plots. ................................ .......... 81 3 16 Density ratings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ .......... 82 3 17 Clipping dry weights from 0 to 52 weeks after treatment (WAT) of Stenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ................................ ................................ ................... 85 3 18 Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of S tenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ................................ ................................ ................................ ................... 86 3 19 Quality ratings from 0 to 52 week s after treatment (WAT) of Stenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. ............................ 87 4 1 Actua l weekly rainfall and irrigation applied to simulated residential landscapes established in a sandy soil in Balm, Florida. ................................ ..................... 1 01 4 2 Mean leachate volume from 0 52 weeks after treatment (WAT) col lected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass. ................................ ................................ .......................... 102 4 3 Mean electrical conductivity (EC) of leachate samples collected from simula ted residential landscape plots where sandy fill soils received compost, tillage and/or aeration soil treatments. ................................ ................................ ........ 103

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12 4 4 Mean concentration of dissolved phosphorus from 0 52 weeks after treatm ent (WAT) in leachate collected from simulated residential landscapes in Florida where soils were amended with composted dairy manure solids. .................... 105 4 5 Mean P load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass. ................................ ................................ .......................... 105 4 6 Mean concentration of nitrate in leachate collected from simulate d residential landscapes in Florida where soils were amended with composted dairy manure solids. ................................ ................................ ................................ .. 108 4 7 Mean concentration of nitrate in leachate collected from simulated residential landscape s in Florida planted with mixed ornamentals and St. Augustine turfgrass. ................................ ................................ ................................ .......... 109 4 8 Mean nitrate load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots pla nted with mixed ornamentals and St. Augustine turfgrass. ................................ ................................ .......................... 109 4 9 Mean concentration of ammonium in leachate collected from simulated residential landscapes in Florida where soils were amended w ith composted dairy manure solids. ................................ ................................ ......................... 111 4 10 Mean ammonium load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass. ................................ ................................ .......................... 111

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13 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECTS OF COMPOST AND TILLAGE ON S OILS AND NUTRIENT LOSSES IN A SIMULATED RESIDENTIAL LANDSCAPE By SHAWNA LOPER December 2009 Chair: Amy L. Shober Major: Soil and Water Science Soil and landscape management practices at new home sites have the potential to negatively impact soil and wat er quality. R esearch has shown that soil management practices such as organic amendment additions or tillage can improve the physical and chemical properties of soil. However, it is not known if these management practices can significantly improve soil c onditions in urban settings, specifically new residential areas. The objectives of this study were to evaluate soil treatment effects on: 1) selected soil physical and chemical properties, 2) plant growth and quality, and 3) nutrient losses in runoff and leachate from simulated residential landscapes Six soil management treatments were evaluated with four replications (24 total plots) in mixed landscape (mixed ornamental species and turfgrass) plots that were established on compacted soils in a randomized complete block design. The soil management treatments were as follows: unamended soil, tillage only, aeration only, compost only, compost + tillage, and compost + aeration. Composted dairy manure solids were applied as an organic solid amendment at a ra te of 508 m 3 ha 1 (25% by volume). Tillage treatments turned the soil to a depth of 10 15 cm. Soil physical and

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14 chemical properties, plant growth and quality, plant tissue nutrients, leachate volume and leachate NO 3 N, NH 4 N and dissolved P were assessed periodically. Applications of compost to soils reduced bulk density and pH and increased soil organic matter, electrical conductivity and concentrations of Mehlich 1 P, K, Ca, and Na. Growth data, with the exception of Raphiolepis indica indicated mor e growth for ornamental plant species grown in soils amended with composted dairy manure solids. In most instances, plant quality and tissue nutrient content were higher for plants grown in soils receiving compost. Soil treatments and vegetative cover ha d no affect on P concentrations in leachate. However, there were soil treatment effects on of NO 3 + NO 2 and NH 4 concentration and load in leachate samples at various times throughout the study, where soil receiving compost leached more than unamended soil s. Leachate volumes were higher under ornamentals than turfgrass. As a result, N losses (load and concentration) under ornamental cover often exceeded losses from turf. Losses of NO 3 + NO 2 were highest during the early weeks of the study, while NH 4 loss es peaked during the warm season as organic N began to mineralize. Results of our study suggest that the addition of compost to soils can improve soil properties and enhance plant growth in residential landscapes when fill soils are used. In contrast, it appears that shallow tillage and aeration had little effect on soil properties or plant growth and quality. Addition of compost did, however, increase nutrient loads in leachate. This creates concerns that o ne time application of low C:N ratio organic am endments at a rate of 25 35% by volume to the top six inches of soil may lead to significant N losses The use of compost as a soil amendment in new residential lawns can be recommended only if the use of inorganic fertilizers is reduced.

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15 CHAPTER 1 LITER ATURE REVIEW AND R ESEARCH O BJECTIVES Population Growth and Urbanization continues to grow (Kozlowski, 1999) When an area is urbani zed, the natural environment is replaced by roads, homes, and commercial structures (Wickham et al., 2002) Based on amount of land covered, urban lands have a disproportional im pact on regional and global systems (Collins et al., 2000; Pickett et al., 20 08) U rbanization can lead to changes in local climate biodiversity, and hydrology, as well as deposition of nutrients and soil disturbance over a large area (Jenerette et al., 2006; Pickett et al., 2008; Pouyat et al., 2006) As the population multiplies, the amount of urban land increases and it becomes more important to manage our soil resources properly. S oil conservation rarely occurs in urbanized areas and soils within these areas are simply (Jim, 1998) Urban soils are described as soil having a non agriculture, man made surface produced by mixing, filling, or by contamination of land surface in urban areas (Bockheim, 1974) I deal ly, an urban soil would be able to resist compaction, have sufficient water holding capacity and permeability, adequate root volume, appropriate soil reaction and fertility, and surface protection (Craul, 1985) ; however this is rarely the case As the population grows, more value has also been placed on aesthet ically pleasing ornamental landscapes (Hipp et al., 1993) The result is an increase in the use of water, fertilizers and pesticides in urban landscapes which can le ad to water quality and supply issues.

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16 Home Site Construction and the Residential Landscape During the construction of residential landscapes, most of the resources go toward plant materials and installation, with the soil receiving little attention (Jim, 1998) Often the topsoil is completely removed during preparation of the home site, which reduces soil organic matter and exposes the less fertile subsoil (Scharenbroch et al., 2005) Topsoil material may be stockpiled for future use at the site or removed from the site completely. Construction related activities, such as the use of heavy equipment, the us e of fill soil materials, and the installation of impervious surfaces can alter the physical properties of the exposed subsoil. The landscape is installed o nce construction is complete. The typical residential landscape contains turfgrass, one or two sh ade trees, and some shrubs. Plant species are often chosen with no regard for their water or fertilizer requirements or suitability to the area, but rather because they are available and cheap (Hipp et al., 1993) By choosing plants that are not suited to the area (e.g., soils, hardiness zone, etc.), homeowners often must apply supplemental fertilizers and irrigation to their landscapes This ultimately increases the chance that nutrients will move offsite and pollute local water systems (Hipp et al., 1993) As a result, many homeowner landscape extension programs, such as the Flo rida Yards and Neighborhoods Program (Florida Yards and Neighborhoods Program, 2006) now encourage the use of landscape materials that are suited f or local growing conditions and require less water and fertilizer inputs as a means to reduce pollution from urban areas. Residential landscapes management practices that minimize fertilizer runoff and leaching are advantageous to both public health and t he environment (Cisar et al., 2004)

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17 Urbanization and Soil Quality Urban land management practices ( e.g., physical disturbance to land, different cover ma terial, management of inputs and vegetation harvest) play an important role in determining soil characteristics, and can have lasting effects on soil for a long period of time (Jenerette et al., 2006) Various construction practices (such as removal of the topsoil, heavy traffic, compac tion of the site) during construction of urban landscapes, result in higher variability of soil conditions than would be found in undisturbed soils (Hamilton and Waddington, 1999) For example, Pouyat et al. (2007) found large variabi lity in surface soil properties of sandy loam soils (e.g. soil bulk density, amount of organic matter, particle size, pH, and nutrient quantities) along an urban rural land use gradient. Urban development can cause a loss of organic matter, loss of soil structure, decreased permeability, and increased compaction (Cogger, 2005) C ompaction has been documented in many urban soils and is generally acknowledged as an obstacle for plant establishment in urban systems (Randrup and Dralle, 1997; Smith and Lawrence, 1985) While compaction is often intentional for site stabilization, it can also be caused inadvertently by heavy equipment that is driven across the soil (Gregory et al., 2006) Soil compaction in urban soils is a common and persist ent occurrence, with bulk densities ranging from normal (approximately 1.4 g cm 3 ) to extremely packed (2.2 g cm 3 ) (Jim, 1998) One study reported bulk densities arou nd 1.8 g cm 3 in residential landscapes (Lichter and Lindsey, 199 4) Individual site sensitivity to compaction is a function of local climate, soil characteristics (Whalley et al., 1995) and the type of construction equ ipment being used (Gregory et al., 2006) Change s to soil physical properties that occur as a result of compaction include: surface crusting destruction of soil aggregates, reduc tion of average pore size, increased soil

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18 strength, and increased bulk density (Gregory et al., 2006; Jim, 19 98; Shestak and Busse, 2005) These changes can lead to problems such as decreased infiltration, reduced water holding capacity, and increased mechanical root impedance (Craul, 1994) all of which pose serious restrictions to plant development (Jim, 1998) Proper land managem ent is important to protect soil function (e.g. infiltration, nutrient cycling) and to maintain the health and durability of plants. Poor urban soil management decisions often lead to problems including: 1) limited root development, which is needed for he althy plant establishment and 2) a reduction in infiltration rates, which leads to runoff and nutrient loss. The current approach to soil management does not address the problems facing plant establishment and pollution concerns (Jim, 1998) Soil conservation and fertility management practices that are based on sound scientific principles are needed in urban areas. Specifically, it is important to take precautions to reduce the occurrence of compaction when developing a residential landscape (Randrup, 1997) Deve lopers must plan appropriately to account for individual site sensitivity to compaction because plant and lawn failure and increased pollution can stem from improper planning. If the developer can factor in the significance of the soil from the beginning, management of the residential landscape after development will be less demanding (Randrup, 1997). Urban ization and Soil Hydrology Urbanization has a greater affect on the hydrology of an area than any other change in land use (Hamilton and Waddington, 1999) C onversion of land from natural conditions to agriculture or urban land use greatly alters the hydrolog ic characteristics of the land surface and modifies the pathway and rate of water flow (Bai et al., 2008) In urban ecosystems the land is covered with impervious surfaces and artificial drainage

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19 systems are installed, both of which affect water movement by increasing runoff and limiting infiltration (Kaye et al., 2006) As a result, urban areas with large population densities have the pote ntial to strongly influence water resources throughout the world (Cisar et al., 2004) Soil compaction that results from construction activities also inf luences urban hydrology by affecting infiltration rates and other hydraulic properties of the soil that directly affect surface runoff, erosion, and groundwater recharge (Defossez and Richard, 2002; Gregory et al., 2006; Hamilton and Waddington, 1999) A study by Zhang et al. (2005) evaluated three different levels of soil compaction on the hydraulic properties of two silt loam soils from the Loess Plateau, China. Results showed that c ompaction of soils (bulk density range = 1.60 1.69 g cm 3 ) changed the water retention curve and decreased the hydraulic conductivity of both soils Gregory et al. (2006) quantified the effects of construction activities on soil infiltration rate of fine sand soils at urban development sites. They found that compaction caused by heavy construction equipment resul ted in an overall decrease in infiltration rates from 733 to 178 mm hr 1 which corresponded with an increase in soil bulk density from 1.34 to 1.40 g cm 3 after compaction. The study concluded that soil compaction has a negative effect on infiltration ra tes in sandy soils and advised avoiding soil compaction to reduce runoff. Meek et al. (1992) evaluated a sandy loam soil and found that infiltration and hydraulic conductivity decreased by 53 and 58%, respectively as bulk density increased from 1.6 to 1.8 g cm 3 A study by Hamilton and Waddington (1999) observed infiltration rates in 15 lawns and suggested that activities, such as topsoil stripping, site traffic, disposal of construction debris, and soil s tratification, can have a significant effect on

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20 soil infiltration rates. The potential for surface runoff from residential landscapes is increased if the soils are compacted and receive intense rainfall (Cisar et al., 2004) Urbanization, Landscape Management and Water Quality In the past traditional agriculture has received most of the blame for off site pollution of nutrients, however urban lands can a lso contribute nutrients to surface water and groundwater (Shuman, 2003) Urbanization and land use have been linked to water quality deg radation. In fact, more than 50% of F affected by urban non point source pollution, which includes nutrients originating from residential landscape (Association of State and Interstate Water Pollution Control Administrators, 1984) For example an increase in NO 3 N was highly correlated with county population growth at the Weeki Wachee Springs in Hernando County, FL (Cisar et al., 2004) The loss of nutrients from residential and commercial landscapes can pose economic losses to homeowners and nutrient losses to plants, as wel l as have ecological consequences (Cisar et al., 2004; Erickson et al., 2005; Gross et al., 1990) Both N and P pose a risk to water quality at relatively low levels, ranging from 0.01 to 0.035 mg L 1 for P and 10 mg L 1 for NO 3 (as set by E PA for human safety) ( Erickson et al., 2001; Mallin and Wheeler, 2000) Coastal areas are often N limited and may be degraded by NO 3 N levels lower than the drinking standard (10 mg L 1 ) (Cisar et al., 2004) Residential land is managed more intensely than agricultural land, which can result in greater losses of N and P from urban systems than from agricultural systems (Bhattarai et al., 2008) As a result, the runoff from urban areas may contain significant levels of N, P, and pesticides due to excessive fertilizer application rates and improper timing of application (Hipp et al., 1993) The rate of chemicals (such as pesticides and fertilizers) applied, the soil moisture content, plant irrigation requirements, and the soil

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21 infiltration rate are important factors that affect amount chemicals and nutrients runoff from landscapes (Cisar et al., 2004; Erickson et al., 2005; Hipp et al., 1993) A large amount of the land is devoted to turfgrass in urban areas (Gross et al., 1990) Considerable inputs of water and fertilizers are needed to establish and maintain healthy, high quality turf (King et al., 2001) Turf dominated landscapes may receive yearly nitrogen and phosphorus applications in excess of 450 kg N h a 1 and 100 kg P ha 1 (Hipp et al., 1993) For example, St. Augustine turfgrass, the most common turfgrass species used in Florida, receives 150 to 300 kg N ha 1 when properly fertilized (Cisar et al., 2004) It is recommend ed that turf irrigation be deep and infrequent to avoid wilting, with the time and amount of wat er to apply depend ing on application rates, month of the year and the climate of the area (Dukes, 2008) In Florida, t urfgrass evapotranspiration ( ET ) demands during dry periods rates range from 3.2 3.3 in per month in cooler months and 5.1 5.7 in per month in warmer months (Dukes, 2008) These high nutrient and water requirements make turf systems a probable source of non point source nutrient pollution to surface and groundwater bodies. Elevated levels of N in watersheds is thought to be a result of fertilizer N runoff and leaching from originating from residential landscapes where turfgrass is routinely fertilized (Erickson et al., 2001 ) However, slower runoff velocities and increased infiltration of water are expected when turf is intensely managed (G ross et al., 1990) Turfgrass and ornamentals reside together in the landscapes and generally receive similar fertilization and irrigation (Saha et al., 2005) despite the fact that t he nutrient and water requirements of ornamental plants differ widely f rom those of turfgrass species. There is significantly less information on te i rrigation re quirements of

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22 ornamentals are less known because of the wide range of plants and the lack of scientific research (Duk es, 2008) Similarly, information about the fertilizer requireme nts of annuals and perennials in the landscape is lacking. However, a few studies have investigated optimum fertilization of ornamental plants growing in the landscape; most have focused on the nutrient requirements of selected woody shrubs and tree species. In general, woody ornamentals likely require less N, P, and K than turfgrass species or more demanding landscape plant type s (e.g., annuals, flowering perennials). Homeowners may be inc lined to add additional fertilizers to their plants when they are not performing as expected, regardless of whether the problem can be attributed to a nutrient deficiency problem. The application of nutrients in excess of plant needs in fertilizers increa ses the potential for nutrients to leach (Shuman, 2003) from or runoff the landscape. Therefore, residential landscape management practic es that minimize fertilizer N in runoff and leachate are advantageous to both humans and the environment (Cisar et al., 2004) Alternatively, Hipp et al. (1993) suggested that establishment of low maintenance landscapes is a practical approach to help prevent pollution because it should reduce chemical i nput and also runoff from residential landscapes. Urbanization and Plant Quality Although urban soils differ from natural soils, the characteristics that support optimal plant growth are the same for both types (Jim, 1998; Whalley et al., 1995) Plants need adequate soil aeration (Unger and Kaspar, 1994) nutrient s and water supply to function and establish properly. However, urban soils often lack these characteristics due to disturbances that occur during construction. Soil compaction is

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23 one of the most common problems stemming from construction in ur ban soils Changes in bulk density that are associated with soil compaction can alter the volumetric water content of the soil, the movement of water in response to water content gradients, the root soil contact, and the level of mechanical impedance to r oot growth (Stirzaker et al., 1996) R esearch has show n that soil compaction impact s root length, root diameter, and the volume of soil that roots are able to explore (Stirzaker et al., 1996; Watson and Kelsey, 2005) For example, Montagu et al. (2001) showed that root gro wth of broccoli seedlings was slowed in a compacted soil. Smiley et al. (2006) reported longer root length and less shoot dieback when Snowgoose cherry ( Prunus serrulata ) and Bosque lacebark elm ( Ulmus parviflia ) trees were grown in uncompacted soils compared with plants grown in compacted or structural soils A study by Stirzaker et al. (1996) found that root length of assorted grasses and clovers was greatest at lower bulk densities and began to shorten as soil bulk density increased. Agronomic c rops grown in compacted soil have fewer lateral roots and less dry matter than plants grown under managed conditions at both low and high soil water contents (Hamza and Anderson, 2005) Soil compaction affect s root growth and development by restricting oxygen, water, and nutrient supply (Glab, 2007) Since most nutrients have limited mobility in soils, roots need to grow to the nutrients to absorb them. However, t he air filled por es that are needed to help roots penetrate the soil, and the water filled pores that are responsible for plant uptake and nutrient transport are often destroyed when soils are compacted (Stirzaker et al., 1996) Plus, since root growth and spread is often

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24 restricted in compacted soils, the ability of plants to capture water and nutrients is also limite d (Jim, 1998; Stirzaker et al., 1996; Unger and Kaspar, 1994; Whalley et al., 1995) Soil compaction also limits soil nutrient holding capacity reducing the amount of nutrients held in available forms to a level that is inade quate to maintain vigorous plant performance (Jim, 1998) The extent of root reduction is mostly dependent on the depth that the compacted restrictive layer occurred within the soil profile (Unger and Kaspar, 1994) A shallow compacted layer that prevents root penetration is very damaging to plant growth and yield when plants are dependent on only precipitation for th eir water supply; under these conditions plants will quickly remove plant available soil water and the plant will exhibit water stress (Unger and Kaspar, 1994) While root limitation has been found to be detrimental, Smith et al. (2001) concluded that roots continued to establish in compacted soils when high levels of available water w ere maintained. Restrictions on root growth that occur as a result of soil compaction can also affect shoot growth and plant vigor (Glab, 2007; Jim, 1998; Watson and Kelsey, 2005) Montague (2001) reported a strong correlation between root length and leaf area indicat ing that shoot growth was reduced when total root length was reduced. Sm i ley et al. (2006) linked t ree decline at development sites to soil compaction and degradation of the root environment When roots growth is restricted in compacted soils, chemical signals within the plant can reduce the size of mature cell in leaves and the number of leaves so plants do not grow as full as they would in uncompacted soils (Beemster and Masle, 1996; Montagu et al., 2001; Mulholland et al., 1999)

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25 Soil Management Practices Proper soil management during construction may improve the survival rate of t urfgrass and landscape plants and reduce the potential for nutrients losses in runoff or leachate For plant survival, soil management should protect or improve conditions so that roots are able to form and penetrate different soil layers (Whalley et al., 1995) To reduce nutrient loss potential, soil mana gement should protect or improve the hydraulic conditions. In both cases, soil management should protect the soil from compaction. Randrup (1997) made the following recommendations for dealing with compaction on construction sites: 1) expect the soil to be compacted, 2) prevent additional compaction, and 3) fence off planting sites to prevent compact ion While reducing compaction as much as possible is recommended, methods to prevent soil compaction should be considered prior to construction (Hanks and Lewandowski, 2003) However, once soil is compacted there may be a few options for improving compacted soils. Tillage When topsoil is removed, tillage of the subsoil before development would be beneficial, since compaction often occur s in the subsoil. Tillage breaks up soil aggregates creating more pore space, thereby allowing water to infiltrate and roots to penetrate through the soil profile (Li piec and Stepniewski, 1995; Vogeler et al., 2005) To alleviate compaction in subsurface soil horizons, tillage equipment needs to reach a depth of two feet or more (Randrup, 1997) Deep tillage allows root growth into deeper soil horizons that have more structure development and greater water holding capacity (Busscher et al., 2006; Lipiec and Stepniewski, 1995) A study by da Silva et al. (1997 ) concluded that tillage contributed to a decrease bulk density by increas ing the resistance of the soil aggregates to compact ion or by increasing recover y of the

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26 compacted soil after the compressive pressure was removed. Research also suggests that spik e and core aeration and rototilling can alleviate soil compaction (Jim, 1993; Kozlowski, 1999; Unger and Kasper, 1994). Organic Amendments The application of organic amendments to soil is gaining favor as an environmental waste management strategy and as a way to improve soil conditions in low fertility soils (Flavel and Murphy, 2006) The a ddition of compost increases s oil organic matter which helps to retain soil water thereby increasing plant available water (Hamza and Anderson, 2005) Studies have shown that organic amendments can also have a positi ve effect on soil bulk density and aggregate stability, especially in course textured soils (Cogger, 2005; da Silva et al., 1997) Similarly, Rivenshield and Bassuk (2007) showed that a sandy loam soil and a clay loam soil, when amended with peat or food waste compost, had lower bulk density and higher macroporosity than those that were not amended, even after recompaction. Applying organic amendments at higher rat es led to more pronounced improvements in density and macroporosity (Rivenshield and Bassuk, 2007) Johnson et al. (2006) also reported that soil bulk density in a clay loam soil decreased as the rate of compost ( added as a topdress ) increased. An other study attributed a n increase in water content and soil water retention to the application of composted yard waste to a sandy soil (Pandey and Shukla, 2006) Organic years after application (Ginting et al., 2003) However, in a warm and moist climates the rate of organic matter decomposition is fast and different characteristics in organic amendments can lead to large differences in the organic matter content of the soil (Albiach et al., 2001)

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27 The use of organic amendments during turfgrass establishment has been shown to increase soil water holding capacity, porosity, and surface area, thereby providing an environment that will allow for the growth of healthy root systems (Cogger, 2005) Studies showed that Kentucky bluegrass establishment could be enhanced by amending the soil with selected organic compost amendments (Landschoot and McNitt, 2004; Linde and Hepner, 2005) Compost amendment treatments provided longer turfgrass response than one time fertilizer treatments and composted land is likely to have fewer weeds (Linde and Hepner, 2005) The application rate of organic amendments in agricultural systems is often based on N content of the material N mineralization, and crop requirement and often leads to applications of P in excess of plant needs (Davis et al., 1997; Jaber et al., 2005) In contrast organic amendments are usually added to soils in turf systems in addition to inorganic fertilizers without taking into account the nutrient content of the amendment (Gaudreau et al., 2002; Johnson et al., 2006) This can lead to an increase in soil nutrient concentrations and the potential for nutrients to be lost in runoff or leachate. Although co mpost is generally applied to add organic matter ( OM ) to the soil, the nutrients supplied by compost additions are also beneficial to plants (Landschoot and McNitt, 2004) Composts conta in all essential plant nutrients; however, the amount and availability of these nutrients varies depending on the compost source (Cogger, 2005) The availability of some nutrients, such as N, in composted materials is lower when compared with un composted materials because decomposition of organic material converts soluble nutrie nts into organically bound forms (Cogger, 2005) Wright et al. (2007b) found that water extractable micronutrients concentrations in compost

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28 amended soils decr eased to below recorded background levels because the addition of compost caused dissolved organic matter to occupy exchange sites to soil particles instead of micronutrients. Stamatiadis et al. (1999) found that despite applying a compost with high NO 3 content, NO 3 levels in the soil were low and similar to the unamended control s oils, suggesting that NO 3 may have been lost through leaching, root uptake, or immobilization and denitrification processes. Johnson et al. (2006) reported no difference in soil NO 3 content when organic dairy cattle manure compost was applied at rates of 0, 33, 66, and 99 m 3 h a 1 The same study found that soil concentrations of P and K increased as compost application rates increased; soil P content of compost amended soils were 187% higher than the in unamended soils. Organic amendments (such as compost) should be managed i n a way that minimiz es the potential for nutrient loss but still optimizes the effect s of the amendment on infiltration, root growth, and compaction (Wright et al., 2007a) Current Research and Needs Soil and landscape management practices at new home sites have the potential to negatively impact soil and water quality. Best management practices need to be developed and implemented in order to minimize the effect of urbanization on soil and water quality and supply. These management practices must be low cost, energy efficient, sustainable, and ecologically sound (Whalley et al., 1995) However, m ore studies are needed to fully understand the impact of soil damag e to root systems and plant health (Watson and Kelsey, 2005) Land developers need to consider the importance of the root environment and implement practices that coinc ide with this into their management. Improved management of urban soils and landscapes will lead to

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29 an improvement in soil and plant properties and aesthetic enhancement of the landscape. The purpose of this study was to determine the effects of applica tion of composted dairy manure solids and tillage practices could reduce the negative impacts of poor soil management practices that lead to issues such as compaction, poor soil fertility, and nutrient loss in newly established landscapes. The specific ob jectives for the research were to evaluate soil treatment effects on: 1) selected soil physical and chemical properties 2) plant growth and quality and 3) nutrient losses in runoff and leachate. A secondary objective was to determine the effect of veget ative cover type (e.g., turf, ornamental landscape plants) on the potential for nutrient leaching from urban landscapes.

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30 CHAPTER 2 EFFECTS OF TILLAGE AND ORGANIC AMENDMENTS ON SOIL PROPERTIES IN A SIMULATED RESIDENTIAL LANDSCAPE Introduction In recent ye ars, Florida has been one of the fastest growing states in the U nited S tates The U.S. Census Bureau forecasts that the population of Florida will increase from 17.8 million people in 2005 to approximately 23.4 million people by 2020 (U.S. Census Bureau, 2004) In many cases, rural land will be converted to urban uses to accommodate the growing population (Heimlich and Krupa, 1994) During urbanization, natural ecosystems are replaced by roads, homes, and commercial structures (Wickham et al., 2002) Construction a nd other human activities associated with urbanization also cause significant disturbance to soils. Studies have shown that urban soils often lack natural soil horizons (Jim, 1998) are significantly compacted (Gregory et al., 2006; Jim, 1998) can have alkaline pH as a result of carbonate release from the calcareous construction waste, and contain low amounts of soil organic matter (OM) N and P (Jim, 1998; Law et al., 2004) As a result, urban soils often require different management strategies than those applied to natural or agricultural soils (Kaye et al., 2006) Residential construction activities can drastically alter soil physical, chemical, and biological properties. During residential construction, topsoil is often removed from the site exposing the subsoil (Hamilton and Waddington, 1999) To psoil material may be stockpiled for future use at the site or removed completely. Construction related activities, such as the use of heavy equipment, the use of fill soil materials, and installation of impervious surfaces can alter the physical properti es of the exposed subsoil. Compaction, which is quantified by high bulk density, is one of the most

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31 common and persistent problems in urban soils (Jim, 1998) Compaction of the soil can be an unintentional result of heavy equipment use and lot grading, or an intentional result of preparing a site to increase structural strength of the soil (Gregory et al., 2006) Research has shown that bulk densities can range from 1.4 g cm 3 (normal) to 2.2 g cm 3 ( extremely packed) in urban soils (Jim, 1998) Similarly, Lichter and Lindsey (1994) reported a bulk density of approximately 1.8 g cm 3 for residential landscapes. When soils are compacted, aggregates are destroyed and soil porosity decreases. As a result, water holding capacity of the soil is decreased, the movement of air and water is reduced and root spread is restricted, ultimately creating an environment that is unsuitable for plant growth (Craul, 1994) Soil hydraulic properties are also impacted by compaction that occurs during urbanization. For exampl e, a study by Zhang et al. (2005) found that a 10% and 20% increase in soil bulk density significantly reduced the saturated hydraulic conductivity of two silt loam soils thereby affecting soil water retention. Gregory et al. (2006) reported an overall decrease of the infiltration rate of s andy soils at a residential construction site, which corresponded with the increase in soil bulk density after compaction that occurred from the use of heavy construc tion equipment. Infiltration rate directly affects surface runoff, erosion and groundwater recharge (Hamilton a nd Waddington, 1999) The potential for surface runoff from residential landscapes is increased when soils with low infiltration rates, resulting from soil compaction, receive intense rainfall or excessive irrigation (Cisar et al., 2004) Tillage can be used to improve the physical properties of compacted soils. In compacted soils, tillage breaks up massive structure thereby increasing soil pore space

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32 a nd allowing water to infiltrate and roots to penetrate through the soil profile (Lipiec and Stepniewski, 1995) da Silva et al. (1997) reported that relative bulk density, which is the ratio of the bulk density of a soil to the bul k density under standard compaction treatment (i.e., samples placed under 200 kPa of pressure), was lower in soils receiving conventional tillage (0.79) when compared with no till soils (0.87). Vogeler et al. (2005) also reported that conventional tillage decreased the soil strength and increased po rosity in a sandy loam agricultural topsoil. The addition of organic amendments (e.g., compost or manure) to soils has been shown to improve soil function by increasing water holding capacity, porosity, and surface area (Cogger, 2005) Zhang (1994) found that moisture retention of silt loam and clay soil aggregates was enhanced when peat moss was added to the soil as a source of organic matter. Adding organic amendments to maintain adequate levels of soil OM by can help to stabilize soil structure (Thomas et al., 1996) Orga nic amendments have also been shown to decrease soil bulk density when applied to soils (Curtis and Claass en, 2009) Curtis and Claassen (2009) found that tillage and application of composted y ard waste decreased the bulk density in four soils (with soil texture ranging from loam to sand) of severely disturbed soils in northern California compared to non tilled treatment Cogger et al. (2008) also reported a decrease in soil bulk density when compost was incorporated in to soils in landscape beds. The addition of organic amendments can also affect s soil ch emical properties. Ginting et al. (2003) reported that the pH of soils amended with beef cattle manure or composted feedlot manure (mean pH = 6.5) was consistently higher than soils fertilized with inorganic fertilizers or unamended soils (mean pH = 6.2). Calcium carbonates

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33 found in land applied manures have been shown to increase soil pH (Eghball and Power, 1999) Ginting et al. (2003) also found that soil EC was higher when soils were a mended with composted feedlot manure soils (0.49 dS m 1 ) compared with unamended soils (0.34 dS m 1 ). Although compost is generally applied to add OM to the soil, the nutrients supplied by compost additions are also beneficial to plants (Landschoot and McNitt, 2004) Composts contain all essential plant nutrients; however, the amount and availability of these nutrients varies depending on the compost source (Cogger, 2005) The availability of some nutrients, such as N, in composted materials is lower when compa red with un composted materials because decomposition of organic material converts soluble nutrients into organically bound forms (Cogger, 2005) Stamatiadis et al. (1999) found that despite applying a compost with high NO 3 content, NO 3 levels in the soil were low and similar to the unamended control soils, suggesting that NO 3 may have been lost through leaching, root uptake, or immobilization and denitrifi cation processes. Johnson et al. (2006) reported no difference in soil NO 3 content when organic dairy cattle manure compost was applied at rates of 0, 33, 66, and 99 m 3 ha 1 The same study found that soil concentrations of P and K increased as compost application rates incre ased; soil P content of compost amended soils were 187% higher than in unamended soils. There is a need to develop soil management practices that can minimize the effects of soil disturbance in residential landscapes. While research has shown that soil m anagement practices such as organic amendment additions or tillage can improve the physical and chemical properties of soil, much of the research has been conducted in

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34 agricultural systems (Martens and Frankenberger, 1992) However, it is not known if these management practices can significantly improve soil conditions in urban settings, specifically new residential areas, where disturba nce of the soil may contribute to environmental degradation. The objective of this study was to determine the effects of adding compost and/or applying shallow tillage on soil physical and chemical properties in a simulated new residential landscape. Ma terial and Methods Experimental Design Twenty four mixed landscape plots (3.05 m x 3.66 m) were established in a randomized complete block design at the University of Florida Institute of Food and Agricultural Science s ( IFAS ) Gulf Coast Research and Educ ation Center in Wimauma, FL to simulate new residential landscapes. All vegetation was removed from the site before plot construction. The entire research area was prepared at a 2% grade (as is typically required by construction codes) and compacted (bulk density range: 1.7 1.9 g cm 3 ) using a small plate compactor (Wacker Neuson, Munich, Germa 0 ny). Individual landscape plots were constructed inside water sealed treated wooden boxes. Within each plot, the compacted field soil (Zolfo fine sand ; sandy, sil iceous, hyperthermic Oxyaquic Alorthods ) (USDA NRCS, 2004) was then buried under 1.13 m 3 of un compacted soil fill material. Soil fill material was create d by mixing three fill soil residential construction. The three fill soil material sources included: a subsoil fill containing construction material and other debris; a clean topsoil material (St. Johns fine sand; sandy, siliceous, hyperthermic Typic Alaquod) obtained from depth of 30 to

PAGE 35

35 60 cm (Hills Dirt Pit, LLC., Riverview, FL), and a clean subsoil fill (St. Johns fine sand) fill obtained from a depth of 122 to 213 c m (Hills Dirt Pit, LLC., Riverview, FL). Composted dairy manure solids (compost; Agrigy, Palm Harbor, FL) were applied as an organic soil amendment at a rate of 508 m 3 ha 1 ( approximately 256 Mg ha 1 ) in combination with two mechanical soil treatments (t illage and aeration) for a total of five soil management treatments. The soil management treatments were as follows: 1) tillage only, 2) compost only, 3) compost + tillage, 4) aeration only, 5) compost + aeration. In plots receiving the tillage treatment soil w as turned to a depth of 10 15 cm using counter rotating tines tiller (Sears Brands, LLC, Hoffman Estates, IL). In plots receiving the aeration treatment, soil aeration plugs were mechanically removed using a core aerator (Billy Goat Industries, In (no tillage or organic amendment) was included as the sixth soil treatment. Once soil treatments were applied, each plot was split and 5.58 m 2 of the plot was planted with Stenotaphrum secundatum (Walter) K untze (St. Augustine turfgrass); the remaining 5.58 m 2 was planted with mixed ornamentals. Mixed ornamentals species included Galphimia glauca Cav. (Thryallis), Rhaphiolepis indica (L.) Lindl. ex Ker Gawl. (Indian hawthorn), Lindl. & Paxton (Buford holly), and Liriope muscari (Decne.) L. H. Bailey (Liriope). Turfgrass was fertilized at a total N rate of 220 kg ha 1 based on current University of Florida Institute of Food and Agricultural Sciences (UF IFAS) recommendations (modera te maintenance schedule for South Florida ): 48.8 kg N ha 1 per application using Lesco Professional turf fertilizer (26 2 11) in February and October, 48.8 kg N ha 1 per application using polymer coated urea ( 42 0 0 tions, Lakeland, FL ) as a slow release N source

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36 in May and August, 24.4 kg N ha 1 with urea ( 46 0 0; Potash Corp., Northbrook, IL) as a soluble N source, and 6.34 L ha 1 of ferrous sulfate (Sunniland Corporation, Sanford, FL ) in July (Sartain, 2007) Ornamental plants were fertilized every 3 months with urea (40 0 0) at an N rate o f 97.6 kg ha 1 based on UF IFAS recommendations for established woody ornamentals grown in the landscape (Knox et al., 2002) The entire research plot area was equipped with a spray irrigation system, which allowed for individual landscape plots to be irrigated, as needed, based on UF IFAS recommendations (Zazueta et al., 2005) During establishment, plots were watered dail y for 30 d after planting to allow for establishment of turf and ornamental plant material. Irrigation frequency was then reduced to two days a week based on typical watering restrictions for landscape irrigation that would be mandated in times of drought (South Florida Water Management District, 2008; St. Johns River Water Management District, 2008) Irrigation was applied for 51 min (irrigation controller run time for two irrigation events per week at an application rate of 0.13 cm per hour, assuming system efficiency of 80% and considering effective rainfall) per plot on Mondays and Thursdays starting at 0 300 HR and ending around 0 900 HR Compost and Soil Characterization Selected physical and chemica l properties of the compost were determined before it was added to the plots as an organic soil amendment. A bulk sample was air dried at room temperature (25 2C) and sieved to pass a 2 mm screen. The pH and EC of the compost was determined using the slurry method and organic matter was determined by loss on ignition (US Composting C ouncil, 2002) T otal C and N concentrations were determined with a Carlo Erba NA 1500 CNS Analyzer (Haak Buchler Instruments, Saddlebrook, NJ) to determine C to N ratio Nutrient content w as determined on a

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37 separate compost sample collected from the sa me dairy as the compost used in our study (Shober, unpublished data) Nutrient content was determined by digesting the compost using the EPA 3050 hot acid digestion (USEPA, 1986) and analyzing the sample for digestible P, Al, Fe, Ca, Mg, and K using in ductively coupled plasma atomic emission spectroscopy (ICP AES) (Perkin Elmer, Waltham, MA). Soil physical and chemical characteristics were measured before tillage and compost treatments were added and then repeated every 3 months (0, 13, 27, 40, and 52 w eeks after treatment [WAT] for a period of one year. Composite soil samples were collected from each plot at 0 10 cm and 10 20 cm depths using a soil probe. Samples were then air dried at room temperature (25 2C) and sieved to pass a 2 mm screen. Soi l pH (1:2 soil to deionized water ratio), electrical conductivity (EC; 1:2 soil to deionized water ratio) and organic matter (OM; loss on ignition) were determined by standard methods of the UF Extension Soil Testing Laboratory (Mylavarapu and Kennelley, 2002) Soil moisture content at field capacity was determined by the method described in Tan (1996) and parti cle size was determined by the hydrometer method (Bouyoucos, 1962) There were no significant changes in soil composition throughout the study; the soils were predominantly sand ( mean = 88%), with very little silt ( mean = 5%) and little clay ( mean = 6%) (Appendix A ). Bulk density was measured using the core method (Blake and Har tge, 1986) and infiltration rate was determined using a double ring infiltrometer (Bouwer, 1986) separately for orn amental and turfgrass cover. The composite soil samples were analyzed for soil test P, K, Mg, Ca, Al, and Fe by Mehlich 1 extraction (1:4 ratio of soil to 0.0125 M H 2 SO 4 + 0.05 M HCl). Mehlich 1

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38 extracts were analyzed by ICP AES. Results from 10 20 cm de pth show ed little treatment effect s and therefore, are reported in A ppendix A Data Analysis The experiment was designed as randomized complete block split plot design with 4 blocks and 6 soil treatments in each block. Half of each plot was planted wit h ornamental plants and the other was planted with turfgrass as described previously. The soil treatments were assigned randomly within each block. Soil properties were analyzed using the PROC MIXED procedure in SAS with soil treatment as a fixed effec t and block as a random effect (SAS Institute, 2003) All comparisons were completed using the Tukey honestly significant difference ( HSD ) test with a significance level 0.05. Results and Discussion Compost and Initial Soil Characterization Initial compost samples had a pH of 6.59, an EC of 1.02 dS m 1 and a total carbon to nitrogen (C:N) ratio of 13.6 (Table 2 2). Li et al. (2009) reported a pH of 6.9, an EC of 4.8 dS m 1 and a C:N ratio of 15. 1 for a separate batch of compost produced at the same dairy as the compost used in our study. Compost nutrient analysis was reported in a previous study (Shober, unpublished data) (Table 2 2). Addition of compost to the plots supplied significant amounts of N, P, and other es sential plant nutrients in addition to the inorganic fertilizers applied to the plots. Plots that received compost applications received a pproximately 3 277 kg total N ha 1 Initial soil samples were divided between the topsoil fill (0 10 cm depth) and t he native field soil (10 20 cm). The topsoil had a pH of 7.5 and an EC of 0.30 dS m 1 The field soil had a pH of 6.5 and EC of 0.49 dS m 1 Initial nutrient content analysis of the

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39 native field soil showed lower nutrient concentrations, with the excep tion of P, when compared to the topsoil (Table 2 1). Phosphorus levels of the topsoil and the native field soil were very high (145 and 77.6 mg kg 1 respectively ). In addition, levels of Mehlich 1 K were medium while Mg was very high. Only application s of N and K fertilizers would be recommended for these soils (Kidder et al., 1998) Initial soil texture classification indicated that the topsoil fill was loamy sand and the native field soil was sand. Table 2 1 Selected chemic al properties of the composted dairy manure solids applied to simulated residential landscapes as an organic soil amendment. Chemical Property Compost pH 6.59 EC, dS m 1 1.02 Total C, g kg 1 174 Total N, g kg 1 12.8 C:N ratio 13 .6 EPA 3050 P, mg kg 1 5410 EPA 3050 Al, mg kg 1 1238 EPA 3050 Ca, mg kg 1 12038 EPA 3050 Fe, mg kg 1 9149 EPA 3050 K, mg kg 1 5362 EPA 3050 Mg, mg kg 1 2560 EPA 3050 Mn, mg kg 1 76 EPA 3050 Na, mg kg 1 1124 EPA3050 nutrient concentrations determined on separate sampl e of composted dairy manure solids from the same dairy that supplied the compost for our study (Shober, unpublished data).

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40 Table 2 2 Selected initial physical and chemical properties of topsoil fill and the native subsoil used in simulated residential landscape plots. Soil Property Topsoil Fill Native Field Soil pH 7.5 6.5 EC, dS m 1 0.3 0.49 Soil texture Loamy sand Sand Mehlich 1 P, mg kg 1 145 77.6 Mehlich 1 K, mg kg 1 2 0 2 9.7 Mehlich 1 Mg, mg kg 1 81.7 18.3 Mehlich 1 Ca, mg kg 1 2300 386 Bu lk Density Due to a significant soil treatment vegetative cover interaction at 13, 40 and 52 WAT (week after treatment) soil bulk density was analyzed separately for each type of vegetation (i.e., mixed ornamentals, turfgrass). Soil bulk density under mixed ornamental vegetation was significantly lower for compost amended soils (1.00, 1.25, 1.09 and 1.07 g cm 3 at 13, 27, 40 and 52 WAT, respectively) when compared with unamended soils (1.65, 1.72, 1.59, and 1.68 g cm 3 at 13, 27, 40 and 52 WAT, respecti vely ) (Table 2 3). In addition, soil bulk density was significantly lower when compost was tilled to 20 cm (1.40 g cm 3 ) than composted soils that were aerated (1.68 g cm 3 ). Under turfgrass cover, soil bulk density was significantly lower for composted soils at 27 and 40 WAT (1.37 and 1.41 g cm 3 at 27 and 40 WAT, respectively) than unamended soils (1.56 and 1.56 g cm 3 at 27 and 40 WAT, respectively) (Table 2 4). No soil treatment effects were reported at 13 or 52 WAT under turfgrass vegetation. Rive nshield and Bassuk (2003) reported that amending both a sandy loam and a clay loam soil with peat or food waste compost resulted in lower soil bulk density and higher macroporosity than una mended soils. Johnson et al. (2006) also reported lower

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41 soil bulk density (1.17 1.46 g cm 3 ) on a clay loam soil, under Kentucky Bluegrass turf at a depth of 0 15 cm when soils were amended with organic dairy cattle manure compost when compared to the control Table 2 3. Bu lk density of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT g cm 3 Control 1.66a 1.68ac 1.63a 1.65a Tillage Only 1.63a 1.81a 1.58a 1.68a Aeration Only 1.67a 1.67ab 1.58a 1.71a Compost Only 0.92b 1.28bc 0.95b 0.85b Compost + Tillage 1.14b 1.32ab 1.17b 1.25b Compost + Aeration 0.95b 1.15b 1.16b 1.12b WAT = week after treatment Values w ithin the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Table 2 4. Bulk density of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with St. A ugustine turfgrass at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT g cm 3 Control 1.51a 1.57a 1.49ab 1.50a Tillage Only 1.57a 1.52ab 1.64a 1.6a Aeration Only 1.36a 1.58a 1.55ab 1.52a Compost Only 1.49b 1.5 1ab 1.40b 1.45a Compost + Tillage 1.32b 1.24b 1.33ab 1.3a Compost + Aeration 1.52b 1.36ab 1.5ab 1.33a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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42 Infiltration Soil infiltration rates were not influenced by soil treatment at any time during the study (Table 2 5 and 2 6). These results differ from those of Weindorf et al. (2006) where infiltration rate increased when clay rich soils were amended with yard waste compost. Meek et al. (1992) also found that infiltration rate increased by >50% when bulk density of a sandy loam was decreased from 1.8 to 1.6 g cm 3 Similarly, Gregory et al. (2006) reported an increase in the infiltration rate of a fine sand from 733 to 178 mm hr 1 when heavy construction e quipment caused an increase in bulk density from 1.34 to 1.49 g cm 3 The lack of treatment effect on soil infiltration in our study could be due to the high sand content and low clay content of the fill and field soils use d in the landscape plots (Table 2 1). Even though our buried field soil was compacted (10 20 cm), the mean soil bulk density reported at the 0 10 and 10 20 cm depths were 1.42 and 1.60 g cm 1 which is considered to be an ideal bulk density for sandy soils and is well below the 1.8 g cm 1 bulk density threshold for root restriction (Hanks and Lewandowski, 2003) In fact, the maximum soil bulk density we reported for soils at 0 10 and 10 20 cm depths were 1.81 and 1.85 g cm 1 respectively.

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43 Table 2 5. Infiltration rate of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots plan ted with mixed ornamentals at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT cm h 1 Control 41.0a 35.1a 39.6a 58.6a 66.7a Tillage Only 41.9a 34.7a 29. 8 a 52.5a 64. 9 a Aeration Only 38.9a 29. 3 a 50. 0 a 47.3a 78. 2 a Compost Only 52.7a 23.6a 34.2a 52. 3 a 70.7a Compost + Tillage 42.6a 32.9a 43.7a 48. 3 a 76.6a Compost + Aeration 45.7a 92.7a 46.9a 46.1a 77. 8 a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Table 2 6. Infiltration rates of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with St. Augustine turfgrass at three sampling dates. Treatment 13 WAT 40 WAT 52 WAT cm h 1 Control 38.7a 50.6a 48.9a Tillage Only 39.0 a 45.4a 51. 4 a Aeration Only 43.3 a 49. 3 a 49. 3 a Compost Only 49.4a 44. 5 a 48.7a Compost + Tillage 42.5a 35.7a 38.0a Compost + Aeration 46. 7 a 50.5a 51.4a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Organic Matter Application of compost increased the soil OM content compared with unamen ded soils through 40 WAT (Table 2 7). While the soil treatment effect on soil OM content at 52 WAT was not statistically significant, soil OM of composted soil was reported to be

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44 higher (31.2 g kg 1 ) than for unamended soils (23.4 g kg 1 ). Pandey and Shu kla (2006) reported higher soil OM content in a sandy field soil amended with 100 Mg ha 1 of composted yard waste ( 22.6 g kg 1 ) compared with the unamended soil (18 1 g kg 1 ). The amount of soil OM in composted soils decreased significantly with time due to oxidation of the compost material, suggesting that the benefits of adding organic matter to soil may eventually be negligible once all the organic matter has bee n oxidized. However, a review by Khaleel et al. (1981) concluded that repeated applications of organic soil amendments can sustain an increase d soil organic matter content Since our project was conducted for only one year, we were not able to determine if multiple applications would maintain higher levels of soil OM compared with unamended soils Time effects of compost applications in Florida are influenced by rapid oxidation due to the warm moist climate. From our study we were unable to evaluate the persistence of the compost ma terial and the related effects on soils after one year. Albiach et al. (2001) found that differences in the degradability of organic amendments can result in large differences in soil OM content in a short amount of time when applied in warm are as where the rate of OM decomposition is fast.

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45 Table 2 7. Soil organic matter of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Tr eatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT g kg 1 Control 16.5a 22.2a 15.0ab 7.00a 14.5a Tillage Only 19.0a 28.6a 8.50a 10.5a 17.5a Aeration Only 17.5a 28.7a 10.0a 13.5ab 43.7a Compost Only 46.3b 63.1b 31.7ab 32.6 bc 30.3a Compost + Tillage 44.8b 60.9b 33.0b 33.1c 31.4a Compost + Aeration 54.4b 60.9b 37.6ab 46.3bc 32.0a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tuk ey's HSD test. Soil pH Soil samples collected immediately after the initiation of soil treatments exhibited no soil pH differences at the 0 10 cm depth (data not shown). This is likely due to the natural buffering capacity of the soil. By 13 WAT, soils t hat received compost additions had a lower soil pH (mean pH = 7.29) than unamended soils ( pH = 7.70); this trend persisted through 52 WAT (Figure 2 1). The decrease in soil pH after application of compost was a result of the pH of the compost ( pH = 6.59; Table 2 2), which was lower than the pH of our fill soils (pH = 7.5; Table 2 1). Other researchers have documented that the pH of compost can influence soil pH when compost is applied to the soil (Eghball, 1999; Eghball, 2002) For example, the incorporation of yard waste compost with a pH of 7.4 raised the pH of several slightly acidic to neutral TX soils (Weindorf et al., 2006) In our study, the pH of unamended soils increased significantly over time (Figure 2 1). This increase may be due to the use of alkaline water (pH = 7.83) for irrigation.

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46 Irrigation of turf with alkaline water was indicated as the cause for a pH increase in a fine sandy loam soil (Wright et al., 2007b) Alternatively, the increase in soil pH could be due to the presence of construction debris in the fill soil material. Some construction debris can cause a rise in pH as the calcium carbonate ric h materials weather (Craul, 1985) Through 40 WAT, there was no temporal effect on soil pH for composted soils (Figure 2 1). While the pH at 52 WAT was significantly higher at 13, 27, and 40 WAT, it was not significantly different than the initial pH. It is likely that, when ap plied to the soil, compost acted to buffer to changes in pH. A study by Stamatiadis et al. (1999) found that surface application of composted dairy manure increased soil buffering capacity, thereby preventing changes in soil pH. Organic matter is able to buffer soil pH because it has many sites that H + ions can bond with in variou s strength; it can also buffer soil by the release of Al +3 ions from organic complexes (Brady and Weil, 2002) Alternatively, it is possible that as the compost decomposed over time, humic and other organic acids were released into the soil; thereby counteracting the liming effect of the irrigation water or construction debris (Brady and Weil, 2002) Albiach et al. (2001) found that application o f municipal solid waste compost increased the level of humic acids in the soil.

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47 Fig ure 2 1. Temporal trend s in soil pH of fill soil samples (0 10 cm de pth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Table 2 8. Soil pH of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots plante d with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT Control 7.46a 7.63a 7.73a 7.66a 7.87ab Tillage Only 7.37a 7.59a 7.76a 7.71a 7.98a Aeration Only 7.48a 7.69a 7.86a 7.76a 7.93ab C ompost Only 7.32a 7.2b 7.11b 7.09b 7.39c Compost + Tillage 7.36a 7.36ab 7.35b 7.32b 7.65bc Compost + Aeration 7.35a 7.22b 7.16b 7.13b 7.43c WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantl y different at P < 0.05 using Tukey's HSD test. E lectrical C onductivity Following the application of compost, the amended soils had a significantly higher EC at 0 10 cm depth than unamended soils; this trend persisted through 27 WAT (Table 2 9). This was likely due to the high EC (1.02 dS m 1 ) in the compost when

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48 compared with the soil fill (0.30 dS m 1 ). Johnson et al. (2006) showed that amending soils with composted dairy manure increased soil EC when the compost application rate exceeded 99 m 3 ha 1 ; t he compost application rate in our experiment was 508 m 3 ha 1 Stamatiadis et al. (1999) also reported an increase in soil EC following application of compost due to the presence of salts ( other than nitrates ) in the compost materia l. After 27 WAT, the s alts likely leached out and we no longer have a difference among the treatments. Table 2 9. Electrical conductivity of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine t urfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT s cm 1 Control 299a 299ab 132abc 400a 223a Tillage Only 316a 291 ab 103 a 310 a 352 a Aeration Only 306a 254c 126 cd 224a 408a Compost Onl y 583ab 39 9bc 177bcd 500 a 292a Compost + Tillage 592b 400 a 196 ab 423 a 384a Compost + Aeration 638 ab 353 c 15 6d 272a 40 7 a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0 .05 using Tukey's HSD test. Field Moisture Capacity Compost application significantly increased the soil field moisture capacity at 0 10 cm depth compared with unamended soils at 0 and 13 WAT (Table 2 10). By 27 WAT, there was a significant compost till age interaction, where soils receiving the compost + tillage treatment maintained a higher field capacity than soils receiving the compost only (52 WAT only) and the compost + aeration (40 and 52 WAT) treatments. Johnson et al. (2006) found that volumetric water content of a c lay loam soil increased as

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49 compost application rates increased ; at saturation soils amended with 66 and 99 m 3 ha 1 compost held 7.2 and 7.9% more water compared to the control ( no compost added ) Aggelides and Londra (2000) reported that applications of compost increased the water retention capac ity of clay and loamy soils In our study, a pplications of compost increased soil OM (Table 2 7), which helps to retain soil water (Hamza and Anderson, 2005) resulting in a higher field moisture capacity. The addition of OM increase s water holding capacity by increasing porosity and surface area; especially in coarse textured soils (Cogger, 2005; Khaleel et al., 1981) Table 2 10. Field moisture capacity of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT % Control 10. 5 ab 12. 3 a 12. 3 ab 12. 6 ab 12. 8 c Tillage Only 10. 1 a 1 2.0 a 11.94ab 12.1 ab 12.6 c Aeration Only 10. 1 a 12.3a 12.30a 11.1a 11.8c Compost Only 21.3 c 19. 9b 14.54c 15.3 bc 15.9 b Compost + Tillage 16.2c 19.9b 13.68d 13.9 c 15.5a Co mpost + Aeration 17.5 bc 19.9b 16.78bc 17.2 b 19 .0 b WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Nutrient Content Soil test (Mehlich 1) P con centrations at 0 10 cm depth were significantly lower for soils receiving the aeration only treatment than soils receiving the only compost or tillage (Table 2 11). At 13 and 27 WAT, soil test P concentrations in composted soils were significantly higher than in the unamended soils. At 52 WAT, composted soils had significantly higher soil test P than the control and aeration only treatments. Gilley and

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50 Eghball (2002) found that soil test (Bray 1) P at 0 5 and 5 15 cm was significantly greater after four years of corn production when composted beef manure was applied based on the N requirements of crops than P requirements. Wright et al. (2007a) reported that NH 4 OAc EDTA extractable P i n soils increased with increasing compost application rates. The increase in P associated with compost additions may increase the risk for P loss from these soils. Nair et al. (2004) reported a P saturation ratio threshold of 0.15 for sandy soils, above which the potential for P loss in runoff or leaching increases greatly. We calculated Mehlich 1 P saturation ratio for these soils and found that all soils exceeded this thresholds due to low concentrations of soil test Al and Fe (Table 2 11). However, a dditions of compost to these sandy soils increased the mean P saturation ratio from 0.23 for unamended soils to 0.34 for composted soils thereby further increasing the risk of P losses from these soils However, Gaudreau et al. (2002) found that P in compost was less soluble and transportable than fertilizer P, but dissolved P in runoff f rom compost soil treatments still raised environmental concerns. Potassium concentrations were significantly higher for composted soils compared with non composted soils at 0 and 13 WAT (Table 2 10). At 27 WAT, the soils receiving the compost + tillage o r aeration only treatments were significantly higher than control and aeration only soils. Potassium concentrations in compost (5362 mg kg 1 ) were much higher than that of the topsoil (20.2 mg kg 1 ) and likely accounts for the difference found among the t reatments. By 40 WAT, there were no significant soil treatment effects on Mehlich 1 K levels, suggesting that K was absorbed by plant roots or leached downward into the soil profile Leaching of K was evident because K concentration s at

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51 10 20 cm depth at 27 and 40 WAT were higher for compost amended soils than unamended soils (Table A 8) Soil treatments had no effect on the concentration of Mehlich 1 Mg except at 27 WAT, when soils that received the tillage only treatment had significantly higher Mehlic h 1 Mg concentrations than the other plots. While the compost added a large amount of EPA 3050 extractable Mg to the soil (Table 2 2), it did not result in an increase in soil test Mg. Wright et al. (2007a) suggested that Mg may form a complex wit h organic matter in the compost and leach below the soil surface. Calcium concentrations at 0 WAT were significantly higher for soils receiving the compost + tillage and compost + aeration treatments compared with control and tillage only treatments. At 13 WAT, all composted soils had higher Mehlich 1 Ca concentrations then uncomposted soils. At 27 WAT, soils receiving the compost + aeration treatment had higher Mehlich 1 Ca than non composted soils. These increases are likely due to the application of Ca associated with the compost materials (Table 2 2) due to Ca supplementation in dairy diets (Toor et al., 2006). By 40 WAT significant differences among treatments were gone. Wright et al. (2007a) theorized that Ca, as was suggested for Mg, co mplexes with organic matter and is leached downward into the soil profile. The concentration of sodium was only affected by soil treatment at 0 WAT; where composted soils had higher concentrations than non composted treatments. The higher Na concentration in composted manure was likely from the salts contained in the manure that were subsequently leached from the soil during irrigation and rainfall events.

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52 Table 2 11. Mehlich I nutrient concentrations (mg kg 1 ) of fill soil samples (0 10 cm) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT mg kg 1 Phosphorus Control 141 ab 12 7 a 14 6 a 12 7 a 15 4 ab Tillage Only 15 7 ab 150ab 16 7 ab 1 80 a 167abc Compost Only 18 1 b 200 c 21 9 c 21 6 a 21 4 c Compost + Tillage 18 4 b 19 1 bc 21 9 c 217a 193bc Aeration Only 1 30 a 135a 172ab 147a 12 2 a Compost + Aeration 17 1 ab 208bc 193bc 226a 212c Potassium Control 23. 3 27. 8 a 19. 8 a 17.5a 24.0a Tillage Only 29. 3 a 35. 3 a 23. 8 ab 35. 3 ab 24.5a Compost Only 21 2 bc 64. 3 b 29. 8 ab 39.0b 25.0a Compost + Tillage 268c 61.0b 37. 3 b 38. 3 b 29.5a Aeration Only 86.5ab 32.5a 21. 3 a 27.5ab 27.0a Compost + Aeration 23 3 bc 55. 8 b 39.5b 37. 8 b 29. 8 a Magne sium Control 2303a 3096a 2681a 1697a 2306a Tillage Only 2335a 3097a 3605b 2488a 2445a Compost Only 2356a 2897a 2672a 2391a 2395a Compost + Tillage 2376a 2869a 2788a 2353a 2392a Aeration Only 2304a 2811a 2511a 2315a 2397a Compost + Aeration 2335a 3023 a 2644a 2310a 2416a Calcium Control 81.5a 17 3 a 17 8 a 128a 20 7 a Tillage Only 80.0a 17 2 a 16 3 a 22 8 ab 182a Compost Only 16 7 ab 330b 215ab 28 9 b 218a Compost + Tillage 22 1 bc 282b 20 7 ab 249b 215a

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53 Aeration Only 123ab 17 7 a 18 5 a 216ab 222a Compost + Aeration 18 3 c 325b 287b 268b 236a Aluminum Control 34.5ab 32. 7 a 32.2a 26. 4 a 25. 6 ab Tillage Only 41. 4 b 3 8.0 a 41.3b 40.5a 34. 4 c Compost Only 27. 3 ab 32. 1 a 35. 7 ab 32.6a 30.6bc Compost + Tillage 29. 2 ab 37.2a 37.1ab 35.6a 34.2c Aeration Only 25. 4 a 30. 3 a 30.1a 28.8a 21.0a Compost + Aeration 27. 7 ab 31.9a 32. 7 ab 35. 1 a 29. 3 bc Iron Control 977a 1000a 1227 a 7 30 a 921ab Tillage Only 1042a 1538b 1262a 1339a 1087b Compost Only 925a 1086ab 1177a 1082a 889a Compost + Tillage 83 9 a 1145ab 1084a 1020a 81 8 a Aeration Only 92 2a 1279ab 1268 a 1139a 917ab Compost + Aeration 843a 99 6 a 1206a 1157a 948ab Sodium Control 10.0a 17.0a 19. 7 a 14.4a 19.2 a Tillage Only 10.3a 21. 9 a 20.0a 2 2.0 a 17. 9 a Compost Only 61.9bc 25. 2 a 22. 4 a 24. 6 a 22. 1 a Compost + Tillage 69.6b 24.7a 23.2a 23. 7 a 22. 6 a Aeration Only 25.5ac 21. 9 a 20.3a 19.3a 19. 4 a Compost + Aeration 69.2b 20. 8 a 25.7a 2 2.0 a 23.8a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HS D test.

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54 CHAPTER 3 EFFECTS OF SOIL TILLAGE AND ORGANIC AMENDMENTS ON PLANT GROWTH AND QUALITY IN A SIMULATED RESIDENTIAL LANDSCAPE Introduction The impact of construction activities and landscape installation not only affects soil properties and water res ources, but also plant growth and performance. Urban construction typically involves land clearing, using heavy equipment, and importation of fill soils, all of which can negatively affect the ability of soils to function properly. For example, the use o f heavy equipment at construction sites has been shown to increase soil bulk density, increase soil strength, and reduce porosity (Smith et al., 2001) Urban soils are often compacted (Gregory et al., 2006; Jim, 1998) exhibit an unnatural and varied soil structure (Jim, 1993) have alkaline pH as a result of weather of construction waste, and contain low amounts of soil organic matter, N and P (Jim, 1998; Law et al., 2004) As a result, the urban soil environment is usually not conducive to healthy root gro wth and function, leading to problems with plant establishment, growth and aesthetic quality (Cogger, 2005; Smith et al., 2001; Watson and Kelsey, 2005; Zhang et al., 2005) In ad dition, u rban soils can impose serious constraints on tree establish ment and growth due to the impact on root growth and function (Smith et al., 2001) Soil compaction, which is quantified by high bulk density, is one of the most common and persistent problems in urban soils (Jim, 1998) While compacted soils provide a stable foundati on for homes, they are not ideal for plant growth (Hanks and Lewandowski, 2003 ) For example, decline and death of trees on construction sites is commonly attributed to soil compaction and the resulting deterioration of the root environment (Wats on and Kelsey, 2005) Compaction reduces the total volume of air filled pores and soil pore size, increases mechanical resistance to root penetration and

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55 can increase or decrease water holding capacity (Whalley et al., 1995) Research shows that compaction from construction can negatively impact root development and density (Watson and Kelsey, 2005) resulting in a loss of plant vigor. A study by Hirth et al. (2005) found that seedling mass, shoot length and root length decreased as the soil bulk density o f a silt loam soil increased from 1.25 to 1.38 g cm 3 Trees with rooting defects associated with compaction will show gradual dieback, reduced longevity, and premature death; new plants will lose vitality and fail to establish (Jim, 1993) Compaction also limits the nutrient holding capacity of the soil, resulting in concentrations of plant availab le nutrients that are inadequate for vigorous plant performance (Jim, 1998) The effect of soil compaction on nutrient transport to the roots ultimately depends on the extent of compaction and on the water and nutrient supply (Lipiec and Stepniewski, 1995) Short root length, restricted range of rooting or po or root soil contact would ultimately limit the ability of a plant to capture water and nutrients (S tirzaker et al., 1996) Soil management practices, such as organic amendment or soil tillage, have been reported to improve the growth of plants in urban soils. A study by Rivenshield and Bassuk (2007) found that the addition of organic amendments (sphagnum peat and food waste compost) increased macroporosity and reduced soil bulk density in a sandy loam and clay loam soil to levels that did not restrict root growth (approximately 1.4 g cm 3 ) The use of organic amendments during turfgrass establishment has been shown to increase soil water holding capacity, porosity, and surface area, thereby provid ing an environment that will allow for the growth of h ealthy root system s (Cogger, 2005) While the addition of compost is a common practice in agriculture it is often neglected in

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56 urban soil management ; however i t should be routinely adopted for long term mainten ance in urban landscapes (Jim, 1998) Studies showed that Kentucky bluegrass establishment could be enhanced by amending the soil with selected organic compost amendme nts (Landschoot and McNitt, 2004; Linde and Hepner, 2005) Tillage has also been suggested as a way to improve plant growth and quality in urban landscapes. T illage br eaks up soil aggregates creat ing more pore space thereby allowing water to infiltrate and roots to penetrate through the soil profile (Vogeler et al., 2005) S tudies have shown that s oil compaction can be alleviated by spike and core aeration and rototilling (Jim, 1993; Kozlowski, 1999; Unger and Kaspar, 1994) Deep tillage (to approximately 0.4 m) allows root growth into deeper soil hori zons with more structur al development and greater water holding capacity (Busscher et al., 2006) While several studies have demonstrated that these soil management practices can improve soil conditions for turfgrass or trees, there is still a need to determine the effects on in urban soil s, specifically new residential areas. Soil disturbance in new residential landscapes may lead to plant failure or poor plant growth when container grown landscape plants and sod are installed. The objective of this study was to determine the effect of a dding compost and/or or applying shallow tillage on plant growth and aesthetic quality in a simulated residential landscape. Materials and Method Experimental Design Twenty four mixed landscape plots (3.05 x 3.66 m) were established in a randomized comple te block design at the UF IFAS Gulf Coast Research and Education Center in Wimauma, FL. All vegetation was removed from the site before plot construction. The entire research area was prepared at a 2% grade (as is typically

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57 required by construction code s) and compacted (bulk density range: 1.7 1.9 g cm 3 ) using a small plate compactor (Wacker Neuson, Munich, Germany). Individual landscape plots were constructed inside water sealed treated wooden boxes. Within each plot, the compacted field soil (Zolfo fine sand: sandy, siliceous, hyperthermic Oxyaquic Alorthods (USDA NRCS, 2004) was then buried under 1.13 m 3 of un compacted soil fill material. Soil fill material was created by mixing three fill soil residential construction. The three fill soil material sources included: a subsoil fill containing construction materia l and other debris; a clean topsoil material (St. Johns f ine sand; sandy, siliceous, hyperthermic Typic Alaquod) obtained from depth of 30 to 61 cm (Hills Dirt Pit, LLC., Riverview, FL), and a clean subsoil fill (St. Johns fine sand) fill obtained from a d epth of 122 to 213 cm (Hills Dirt Pit, LLC., Riverview, FL). Initial soil and compost properties are reported in Chapter 2, Table 2 1 and 2 2. Composted dairy manure solids (compost; Agrigy, Palm Harbor, FL) were applied as an organic soil amendment at a rate of 508 m 3 ha 1 ( approximately 256 Mg ha 1 ) in combination with two mechanical soil treatments (tillage and aeration) for a total of five soil management treatments. The soil management treatments were as follows: 1) tillage only, 2) compost only, 3 ) compost + tillage, 4) aeration only, 5) compost + aeration. In plots receiving the tillage treatment, soils were turned to a depth of 10 15 cm using counter rotating tines tiller (Sears Brands, LLC, Hoffman Estates, IL). In plots receiving the aeration treatment, soil aeration plugs were mechanic ally removed using a (no tillage or organic amendment) was included as the sixth soil treatment.

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58 Once soil treatments were applied, each plot was split and 5.58 m 2 of each plot was planted with Stenotaphrum secundatum (Walter) Kuntze (St. Augustine turfgrass); the remaining 5.58 m 2 was planted with mixed ornamentals. Mixed ornamentals species included Galphimia glauca Cav. ( Thryallis), Rhaphiolepis indica (L.) Lindl. ex Ker Gawl. (Indian hawthorn), Ilex cornuta Burfordi Lindl. & Paxton (Buford holly), and Liriope muscari (Decne.) L. H. Bailey ( Liriope ). Turfgrass was fertilized at a total N rate of 220 kg ha 1 based on cur rent University of Florida Institute of Food and Agricultural Sciences (UF IFAS) recommendations (moderate maintenance schedule for South Florida ): 48.8 kg N ha 1 per application using Lesco Professional turf fertilizer (26 2 11) in February and October, 48.8 kg N ha 1 per application using polymer coated urea (42 0 0; H release N source in May and August, 24.4 kg N ha 1 with urea (46 0 0; Potash Corp., Northbrook, IL) as a soluble N source, and 6.34 L ha 1 of ferrous sulfate (Sunniland Corporation, Sanfor d, FL) in July (Sartain, 2007) Ornamental plants were fertilized every 3 mon ths with urea ( 46 0 0) at an N rate of 97.6 kg ha 1 based on UF IFAS recommendations for established woody ornamentals grown in the landscape (Knox et al., 2002) The entire research plot area was equipped with a spray irrigation system, which allowed for individual landscape plots to be irrigated, as needed, based on UF IFAS recommendations (Zazueta et al., 2005) During e stablishment, plots were watered daily for 30 d after planting to allow for establishment of turf and ornamental plant material. Irrigation frequency was then reduced to two days a week based on typical watering restrictions for landscape irrigation that would be mandated in times of drought (South Florida Water Management District, 2008; St. Johns River Water Management

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59 District, 2008) Irrigation was applied for 51 min (irrigation controller run time for two irrigation events per week at an application rate of 0.13 cm per hour, assuming system efficiency of 80% and considering effective rainfall) per plot on Mondays and Thursdays starting at 0 300 HR and ending around 0 900 HR Plant Growth and Quality P lant growth measurements and quality ratings were co llected monthly to evaluate the effect of soil tillage or compost amendment on the establishment and growth of ornamental plants and turfgrass. Growth index (GI) was used as a quantitative indicator of o rnamental plant growth rate and to compare the size of the plants grown under different soil treatments. Growth index for each plant was calculated as: GI (m 3 )= H W1 W2; where H is the plant height (m), W1 is the widest width (m), and W2 is the width perpendicular to the widest width (m) (Scheiber et al., 2007) Turfgrass was mowed on an as needed basis, with most collections occurring during the summer months. Turf clippings were collected to determine clipping dry weight based on the method outlined by Ervin and Koski (2001) with some modifications. A 0.46 m wide section from the center of each plot was mowed to a height of 5.7 cm. Th e clippings were collected from a bag attached to the mower after every plot and then dried to a constant mass at 105C and weighed. Plant greenness readings were collected monthly using a SPAD meter (SPAD 502, Spectrum Technologies INC., Plainfield, IL). Quality ratings, density and dieback, were used to put uniformity, color, density, and visual appeal into numerical representation. Quality ratings for ornamental plant species were taken on a 1 5 scale with the following rating system: 5 (dense, good p lant quality) to 1 (very poor plant quality). Turfgrass ratings were taken on a scale of 1 5 based on the percentage of turf area exhibiting symptoms with the following rating

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60 system: 1 (75 100% stressed), 2 (50 75% stressed), 3 (25 50% stressed), 4 (1 25 % stressed), and 5 (0% stressed). The plant was considered to be stressed is when it showed visible signs of strain such as discoloration, lack of growth, or even cessation. Plant Tissue Analysis Ornamental and turf tissue samples were collected by rand omly sampling approximately 40 50 leaves or blades of grass from each plot every 3 months. Plant tissue samples were dried at 105C and digested using the standard method of the UF IFAS Extension Soil Testing Laboratory (Mylavarapu and Kennelley, 2002) and analyzed for total Kjeldahl N, and total P and K by inductively coupled plasma atomic emission spectroscopy (ICP AES) Data Analysis The experiment was desig ned as randomized complete block split plot design with 4 blocks and 6 soil treatments in each block. Half of each plot was planted with ornamental plants and the other was planted with turfgrass as described previously. The soil treatments were assign ed randomly within each block. Plant GI was analyzed using the PROC MIXED procedure in SAS with soil treatment as a fixed effect and block as a random effect (SAS Institute, 2003) Initial GI (0 WAP) was included in the model as a covariate to account for variation in initial plant size at different sampling dates. All comparisons 0.05. Plant quality data were analyzed using the PROC GLIMMIX program in SAS (SAS Institute, 2003) with the multinomial distribution and the cumulative logit link functi on. All comparisons were completed using the 2 test with a significance level of

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61 Results Galphimia G lauca The growth index (GI) of the G glauca showed soil treatment effects starting at 19 WAT (weeks after treatment) (Figure 3 1). G glauca g rew larger in landscape plots where compost was applied to the soil than in soils that did not receive compost. Data collected from 15 24 WAT showed that tilling the compost into the soil to a depth of 20 cm resulted in more plant growth than applying com post to the soil surface. Plants grown in composted soils displayed higher SPAD values than uncomposted soils. However, these differences were not statistically significant (Figure 3 2) until 37 WAT, at which time SPAD readings for plants grown in plots that received the compost + aeration treatment were significantly higher than for plants grown in the control (no compost/no tillage) plots. At 45 WAT, G glauca SPAD readings were higher for plants grown in soils receiving the compost only treatment tha n those grown in the control and aeration only plots. Soil treatments had a significant effect on density ratings at 11, 15, 19, 24, 28, 45, and 49 WAT (Figure 3 3). Dieback ratings were affected by treatment effect at 11, 15, 24, 28, 32, 27, 40, 45, an d 49 WAT (Figure 3 4). For both density and dieback, G. glauca planted in compost amended soils were rated higher than shrubs grown in unamended soils (Figure 3 3 and 3 4). Tillage and aeration resulted in plants with comparable quality ratings to those grown in the control plots. Soil treatments affected the nutrient content in plant tissue throughout the study (Table 3 1) Total Kejdahl N in the tissue of G glauca shrubs grown in compost ed soils treatments at 13 and 27 WAT were significantly higher th an tissue from shrubs grown on unamended soils At 40 and 52 WAT plants grown in the soils receiving the

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62 compost only treatment had significantly higher tissue TKN than plants grown in un amend ed soils At 13 WAT, tissue total P was significantly higher for plants grown in soils receiving the compost only treatment compared to those grown in unamended soils ; there were no significant differences in tissue P at any other time in the study For total K in tissue the tillage only treatment led to significa ntly higher tissue K levels than the aeration only, compost only, and compost + aeration treatments at 13 WAT only Figure 3 1. Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of G glauca grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0 05) between composted treatments and non composted treatments. Double star (**) indicates a significant difference (P <0.05) between compost + tillage and non composted treatments. Plus sign (+) indicates a significant difference (P <0.05) between compost only, compost + aeration and control. Double plus sign (++) indicates a significant difference (P <0.05) between com post only and tillage only, aeration only. Arrow (^) indicates a significant difference (P <0.05) between compost only, compost + aeration and tillage only.

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63 Figure 3 2. Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of G glauca grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between compost +tillage, compost + aeration and non composted treatments. Dou ble star (**) indicates a significant difference (P <0.05) between compost + aeration and control treatment. Plus sign (+) indicates a significant difference (P <0.05) between compost only and control, aeration only plots.

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64 Figure 3 3. Dieback ratings fr om 0 to 52 weeks after treatment (WAT) of G glauca grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. V alues within the same sampling date (WAT) with the same letter are not s ignificantly different at P < 0.05 using the 2 test.

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65 Figure 3 4. Density ratings from 0 to 52 weeks after treatment (WAT) of G glauca grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. V alues within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using the 2 test.

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66 Table 3 1. N utrient content in plant tissue collected from G. glauca grown in sandy fill soils receiving compost, shallow tillage, and/or aeration treatments i n simulated residential landscape plots at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT % Total Kejdahl N Control 1.35a 1.45a 1.55a 2.25ab Tillage Only 1.25a 1.32a 1.54a 2.07a Aeration Only 1 .31a 1.40a 1.46a 2.08a Compost Only 2.33b 2.46b 3.16b 2.59b Compost + Tillage 2.41b 2.24b 2.20ab 2.51ab Compost + Aeration 2.05b 2.29b 2.15ab 2.40ab Total Phosphorus Control 1.56a 2.11a 2.90a 3.58a Tillage Only 1.63ab 2.24a 2.74a 3.57a Aeration Only 1.75ab 2.01a 2.82a 3.64a Compost Only 3.13c 2.41a 2.84a 3.64a Compost + Tillage 2.35bc 2.60a 2.55a 3.22a Compost + Aeration 2.82bc 2.53a 2.62a 3.25a Total Potassium Control 4.56a 5.12ab 5.22a 9.32a Tillage Only 5.45a 5.74b 5.17a 10.76a Aeration Onl y 5.47a 4.60a 4.74a 9.76a Compost Only 6.07a 4.53a 4.99a 8.09a Compost + Tillage 5.78a 5.37ab 5.27a 9.02a Compost + Aeration 5.26a 4.30a 5.07a 7.55a WAT =week after treatment Values within the same sampling date (WAT) with the same letter are not sig nificantly different at P < 0.05 using Tukey's HSD test.

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67 Raphiolepis I ndica There were no significant soil treatment effects on the GI of R. indica during the study period (Figure 3 5). Chlorophyll readings for R. indica grown in compost amended soils wer e significantly higher than shrubs grown in amended soils at 45 WAT only (Figure 3 6). Starting at 28 WAT there were significant differences in dieback ratings, where composted treatments resulted in higher ratings than the non composted treatments (Figu re 3 7). Density ratings showed significant differences starting at 19 WAT for composted treatments when compared with n on com posted treatments (Figure 3 8). The nutrient content of R. i ndica tissue was affected by soil treatment throughout the study (T able 3 2) At 13 and 40 WAT, tissue had higher levels of TKN when plants were grown in composted soils when compared with unamended soils At 27 WAT the compost only treatment led to higher TKN levels than the non composted treatments At 40 WAT, tissu e t otal P was significantly higher in R. indica plants grown in soils receiving the compost + aeration compared with the aeration only treatment T issue t otal K was signi fi cantly higher plants grown in soils receiving the compost + aeration compared with plants grown with the tillage only treatment at 27 WAT A t 40 WAT the compost + aeration treatment led to higher tissue total K than the aeration only treatments. This trend was reversed a t 52 WAT where the tissue t otal K concentrations were significan tly lower from plants grown in composted soils than those grown in unamended soils

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68 Figure 3 5. Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Figure 3 6. Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between compost only, compost + aeration and tillage only.

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69 Figure 3 7. Dieback ratings from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving comp ost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Values within the same sampling date (WAT) with the same letter are not 2 test.

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70 Figure 3 8. Density ratings from 0 to 52 weeks after treatment (WAT) of R. indica grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Values within the same sampling date (WAT) with the same letter are not 2 test.

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71 Table 3 2 Nutrient content in plant tiss ue collected from R. indica grown in sandy soils receiving compost, shallow tillage, and/or aeration treatments in simulated residential landscape plots at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT % Total Kejdahl N Control 1.60a 1.56abc 1.53a 1.21a Tillage Only 1.53a 1.35a 1.39a 1.20a Aeration Only 1.59a 1.43ab 1.41a 1.23a Compost Only 1.88b 1.84d 1.90b 1.68a Compost + Tillage 1.90b 1.65bc 1.92b 1.65a Compost + Aeration 1.91b 1.79cd 2.1 0b 1.67a Total Phosphorus Control 2.07a 2.30a 2.55ab 3.15a Tillage Only 2.33a 2.41a 2.64ab 3.24a Aeration Only 1.94a 2.13a 2.44a 3.19a Compost Only 2.25a 2.77a 3.12ab 3.10a Compost + Tillage 2.10a 2.30a 2.53ab 2.64a Compost + Aeration 2.50a 2.71a 3. 48b 3.57a Total Potassium Control 7.98a 9.14ab 8.42ab 8.00a Tillage Only 7.77a 8.19a 8.83ab 8.72a Aeration Only 7.75a 8.48ab 8.05a 7.96a Compost Only 8.80a 9.77ab 9.25ab 6.08b Compost + Tillage 8.72a 9.68ab 9.50ab 5.96b Compost + Aeration 8.87a 10.0 2b 10.21b 7.12ab WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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72 Ilex C ornuta The GI of I. cornuta il treatment from 28 to 49 WAT. After 28 WAT, shrubs grown in soils receiving applications of compost grew larger than shrubs grown in soils that received no compost (Figure 3 9). Tilling the compost into the top 20 cm of the soil did not improve plant g rowth at most sampling dates compared with treatments where no compost was applied to the soil. Plant SPAD readings exhibited significant soil treatment effects at 32, 40 and 49 WAT (Figure 3 10). At 32 WAT, I. cornuta ng the compost only t reatment (no tillage or aeration) had higher readings than shrubs grown in unamended soils (Figure 3 10). At 40 WAT and 49 WAT, SPAD readings were lower for I. cornuta t only or compost + aeration treatments, respectively. Density and dieback ratings were significantly affected by soil treatments starting at 28 WAT; in general density and dieback ratings were better for shrubs grown in compost amended soils than for shr ubs grown in unamended soils (Figure 3 11 and 3 12). Soil treatment had a significant effect on p lant tissue nutrient content (Table 3 3) Total Kejdahl N in tissue collected from I. cornuta compost + aeration and compost only treatments were significantly higher than in plants grown in unamended soils at 13 WAT. At 27 and 40 WAT tissue collected from plants grown in composted soils had higher TKN than plants grown in unamended soils A t 52 WAT tissue concentrat ions of TKN were higher for the compost only treatments than the unamended soils Soil treatment effects on tissue t otal P began at 40 WAT, where compost treatments led to higher tissue concentrations of P than un composted treatments By 52 WAT, only the compost + tillage led to higher tissue P concentrations

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73 than the tillage only and aeration only treatments T issue t otal K was only affected by soil treatments at 27 WAT, where the control and tillage only treatments led to lower tissue K concentrations than the other soil treatments. Figure 3 9. Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential lands cape plots. Star (*) indicates a significant difference (P <0.05) between compost only, compost + aeration and non composted treatments.

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74 Figure 3 10. Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils r eceiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between compost only and non composted treatments. Double star (**) indicates a significant diff erence (P <0.05) between compost + aeration and control, aeration only treatments. Plus sign (+) indicates a significant difference (P <0.05) between compost only and aeration only treatments. Double plus sign (++) indicates a significant difference (P < 0.05) between compost + aeration and aeration only treatments.

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75 Figure 3 11. Dieback ratings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated reside ntial landscape plots. Values within the same sampling date (WAT) with the same letter are not 2 test.

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76 Figure 3 12. Density ratings from 0 to 52 weeks after treatment (WAT) of I. cornuta grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Values within the same sampling date (WAT) with the same letter are not 2 test.

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77 Table 3 3. Nutrient co ntent in plant tissue collected from I. cornuta grown in sandy soils receiving compost, shallow tillage, and/or aeration treatments in simulated residential landscape plots at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT % Total Kejdahl N Control 1.61ab 1.27a 1.29a 1.40ab Tillage Only 1.52a 1.24a 1.18a 1.18a Aeration Only 1.60ab 1.29a 1.30a 1.24ab Compost Only 1.79bc 1.68b 1.89b 1.77c Compost + Tillage 1.71ab 1.59b 1.71b 1.65bc Compost + A eration 1.89c 1.59b 1.68b 1.76bc Total Phosphorus Control 1.21a 1.11a 1.29ab 1.23ab Tillage Only 1.02a 1.09a 1.13a 1.06a Aeration Only 1.10a 1.19a 1.24a 1.17a Compost Only 1.18a 1.33a 1.60c 1.36ab Compost + Tillage 1.01a 1.14a 1.55bc 1.59b Compost + Aeration 1.31a 1.34a 1.66c 1.37ab Total Potassium Control 5.54a 5.33a 5.53a 4.36a Tillage Only 4.74a 5.36a 5.40a 4.19a Aeration Only 5.12a 5.48ab 5.52a 4.59a Compost Only 5.32a 7.29b 5.48a 4.18a Compost + Tillage 4.54a 6.58ab 5.46a 4.07a Compost + Aeration 6.19a 7.16ab 5.88a 4.18a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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78 Liriope M uscari There was a significant soil treatment effe ct on the GI of L. muscari starting at 19 WAT (Figure 3 13). In general, soils amended with compost produced L. muscari with higher GI than plants grown in the unamended soils. Surface applications of compost (no tillage or aeration) produced larger L. m uscari plants than unamended soils from 32 through 49 WAT, while composted soils that were aerated produced larger plants than unamended soils at 32, 40 and 49 WAT. Incorporation of the compost by tilling to a depth of 20 cm only improved growth over unam ended soils at 19 and 49 WAT. Plant SPAD readings for L. muscari were affected by soil treatment at 24, 37, 40 and 45 WAT (Figure 3 14). Treatment effects were mixed, however, at each date one or more of the compost treatments resulted in higher chlorop hyll readings than plants grown in plants grown in unamended soils. By 11 WAT, soil treatments were significantly affecting plant density and dieback ratings for L. muscari (Figure 3 15 and 3 16). In general, L. muscari grown in compost amended soils ha d better density and dieback ratings than plants grown in unamended soils. Soil treatments affected the plant nutrient content of TK N and total P for L. muscari (Table 3 4). At 13 WAT, TK N in tissue was significantly higher from plants grown in composted soils compared with those grown on unamended soils At 27 WAT the compost + tillage and compost + aeration treatments led to TKN concentrations that were significantly higher than for plants grown in soils receiving the other treatments. At 40 WAT TKN in plant tissue from L. muscari grown in composted soils were significantly higher than for plants grown in unamended soils. A t 52 WAT the compost only treatment resulted in plants with higher TKN than plants grown in unamended soils T issue t otal P exhi bited soil treatment effects by 13 WAT, where the control and

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79 aeration only treatments led to higher tissue P than plants grown in soils receiving the compost only treatment. At 40 WAT plants grown in soils receiving the control and aeration only treatme nts had significantly higher tissue P than plants grown in soils where compost was applied. A t 52 WAT the control treatment produced plants with higher tissue P than the compost + aeration treatment Soil treatments did not affect levels of tissue total K at any time throughout the project. Figure 3 13. Mean canopy growth index from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landsca pe plots. Star (*) indicates a significant difference (P <0.05) between compost only, compost + aeration and non composted treatments. Double star (**) indicates a significant difference (P <0.05) between compost + tillage and control treatments. Plus s ign (+) indicates a significant difference (P <0.05) between composted treatments and control, aeration only treatments. Double plus sign (++) indicates a significant difference (P <0.05) indicates significant difference between compost only and non compo sted treatments. Arrow (^) indicates a significant difference (P <0.05) indicates significant difference between compost and non composted treatments.

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80 Figure 3 14. Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sand y fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between composted treatments and tillage only, aeration only. Double star (**) ind icates a significant difference (P <0.05) between compost + tillage and non composted treatments. Plus sign (+) indicates a significant difference (P <0.05) between composted treatments and tillage only.

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81 Figure 3 15. Dieback ratings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Values within the same sampling date (WAT) w ith the same letter are not significantly di 2 test.

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82 Figure 3 16. Density ratings from 0 to 52 weeks after treatment (WAT) of L. muscari grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Values within the same sampling date (WAT) with the same letter are not 2 test.

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83 Table 3 4. Nutrient content in plant tissue collected from L. muscari grown in sandy soils receiving compost, shallow tillage, an d/or aeration treatments in simulated residential landscape plots at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT % Total Kejdahl N Control 2.39ab 1.84a 2.00a 1.60a Tillage Only 2.33a 1.89ab 1 .91a 1.67ab Aeration Only 2.34a 1.84a 2.05a 1.60a Compost Only 2.60c 2.16ab 2.66b 2.10b Compost + Tillage 2.73c 2.30c 2.45b 2.04ab Compost + Aeration 2.64bc 2.19bc 2.46b 2.01ab Total Phosphorus Control 5.58b 6.77a 4.81c 5.00b Tillage Only 5.06ab 5.0 8a 4.56bc 4.22ab Aeration Only 5.91b 6.80a 5.07c 4.60ab Compost Only 4.20a 4.59a 3.57ab 3.91ab Compost + Tillage 4.28ab 3.74a 3.46a 3.91ab Compost + Aeration 4.69ab 4.84a 2.90a 3.18a Total Potassium Control 9.46a 8.77a 5.76a 4.54a Tillage Only 8.57a 5.98a 5.68a 4.70a Aeration Only 9.56a 7.38a 5.10a 4.11a Compost Only 8.92a 7.41a 4.55a 4.62a Compost + Tillage 9.41a 7.01a 5.03a 4.23a Compost + Aeration 9.43a 6.65a 4.59a 3.37a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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84 Stenotaphrum S ecundatum During the summer months (15 28 WAT), the dry mass of turf clippings was greater from compost amended soils compared with uncomposted soils ( Figure 3 17). During other times of the year, soil treatment had no effect on the mass of turf clippings collected. While soil treatment effects on turf SPAD readings were only significant at 19 and 28 WAT (where either the compost + tillage or compost o nly treatments resulted in higher SPAD readings than the aeration only treatment), there was a trend where turf grown on compost amended soils typically had higher SPAD readings (mean 37.74 nm) than unamended soils (mean 35.93 nm). Soil treatments had no effect on turf quality (Figure 3 19). Soil treatments had a significant effect on tissue nutrient content (Table 3 5) T urf tissue concentrations of TKN were significantly higher when turf was grown on composted soils from 13 through 40 WAT. At 52 WAT, the compost + tillage and compost + aeration treatments produced turf with higher TKN than the unamended soils and the compost only treatment produced turf with higher TKN than the control and tillage only treatments T issue t otal P was affected by soil treatment starting at 13 WAT, where composted treatments led to higher turf tissue P than the unamended soils (Table 3 5) At 27 WAT turf grown on unamended soils had higher tissue P than when grown on composted soils A t 40 WAT tillage only and aerat ion only treatments produced turf with significantly higher tissue P concentrations than the composted treatments while the control treatment produced turf with higher P than the compost only treatment By 52 WAT there were no longer soil treatment effe cts on tissue P

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85 Soil treatments affected turf tissue t otal K had significant differences at 13 WAT when composted treatments produced turf with higher K concentrations than non composted treatments (Table 3 5) By 27 WAT turf grown on soils receiving the compost + aeration treatment had higher K than turf grown on soils receiving the tillage only treatment. A t 40 WAT application of compost resulted in higher tissue K concentration than the non composted treatments. As with total P, there was no sig nificant effect of soil treatment on tissue total K content at 52 WAT. Figure 3 17. Clipping dry weights from 0 to 52 weeks after treatment (WAT) of Stenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration trea tments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between composted and non composted treatments. Double star (**) indicates a significant difference (P <0.05) between compost only and tillage only, c ontrol treatments.

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86 Figure 3 18. Mean SPAD readings from 0 to 52 weeks after treatment (WAT) of Stenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. Star (*) indicates a significant difference (P <0.05) between compost + tillage and non composted treatments. Double star (**) indicates a significant difference (P <0.05) between compost only and aeration only treatments.

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87 Figure 3 19. Quality ratings from 0 to 52 weeks after treatment (WAT) of Stenotaphrum secundatum grown in sandy fill soils receiving compost, shallow tillage and/or aeration treatments in simulated residential landscape plots. V alues within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using the 2 test.

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88 Table 3 5. Nutrient content in plant tissue collected from Stenotaphrum secundatum grown in sandy soils receiving compost, shallow tillage, and/or aeration treatments in simulated land scape plots at four sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT % Total Kejdahl N Control 1.81a 2.38a 1.73a 1.93a Tillage Only 1.88a 2.31a 1.72a 1.85a Aeration Only 2.03a 2.53a 1.68a 2.21ab Comp ost Only 2.81b 3.31b 2.72b 2.78b Compost + Tillage 2.87b 3.26b 2.61b 2.85bc Compost + Aeration 2.62b 3.28b 2.81b 3.08c Total Phosphorus Control 4.51a 5.50b 4.91bc 4.39a Tillage Only 4.44a 5.74b 5.13c 4.26a Aeration Only 4.75a 5.83b 5.16c 4.86a Compo st Only 6.19b 4.47a 4.02a 4.69a Compost + Tillage 6.81b 3.91a 4.36ab 5.14a Compost + Aeration 6.66b 4.08a 4.24ab 4.24a Total Potassium Control 14.09a 17.15ab 10.14a 9.92a Tillage Only 13.56a 16.78a 10.44a 9.66a Aeration Only 15.13a 17.73ab 10.11a 10. 92a Compost Only 18.13b 17.93ab 13.58b 11.40a Compost + Tillage 20.62b 19.46ab 16.09b 12.54a Compost + Aeration 18.81b 20.11b 16.14b 11.72a WAT = week after treatment Values within the same sampling date (WAT) with the same letter are not significan tly different at P < 0.05 using Tukey's HSD test.

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89 Discussion The GI data for the ornamental plants, with the exception of R. indica indicated more growth for plants grown in soils amended with compost ed dairy manure solids A study by Rivenshield (2003) also found that additions of food waste compost to compacted urban soil increased plant vigor and growth of Acer saccharum and Acer saccharinum trees The lack of significant effect on R. indica may be due to the plants adaptability to a wide range of soil conditions. The improved growth of plants in composted soil s may be explained by the additional nutrients contained in the compost (Table 2 3). In most instances plant tissue nutrient content was higher when plants were grown in soils receiving composted compared with those grown in unamended soils Compost application s have been shown to improve turf establishment and provide a healthy environment for root establishment (Cogger, 2005) I n our study, the bulk density of compost amended soils was lower (1.00, 1.25, 1.09 and 1.07 g cm 3 at 13, 27, 40 and 52 WAT, respectively) than non composted soils (1.65, 1.72, 1.59, and 1.68 g cm 3 at 13, 27, 40 and 52 WAT, respectively ) (Table 2 3). However, t he bulk density of the unamended soils was below the 1.8 g cm 1 bulk density threshold for root restriction for a sandy soil (Hanks and Lewand owski, 2003) suggesting that bulk density likely to influence plant growth in our study. In addition, we found that application of compost improved soil field moisture capacity (Table 2 10), thereby increasing the volume of plant available water in the soil. Pandey and Shukla (2006) reported that the application of 100 Mg ha 1 yard trimming compost to soils at a commercial vegetable farm increased the soil moisture content compared with soils where no compost was appli ed However, since plant water stress was not

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90 measured in this study, we cannot definitively say that the increase in the water holding capacity of the soil was responsible for the increase i n plant growth. Plant SPAD readings were typically higher for plants grown in soils receiving composted treatments versus non composted treatments in our study. Similar results were reported by Smiley et al. (2006) who found that th e mean SPAD readings of Prunus serrulata and Ulmus parvifolia grown in a sandy clay loam soil were significantly higher when grown in non compacted/suspended pavement treatment than when grown in a gravel/soil mixture, Stalite/soil mixture, Stalite, or a c ompacted soil. In our study, high SPAD readings were likely due to the addition of nutrients in the compost. In our study plant tissue N content was typically higher for plants grown in composted soils than for plants grown in the unamended soils SPAD readings measure the ratio of the amount of light transmitted through a leaf at two wavelengths; one that is absorbed by chlorophyll and the other one is not (Ntamatungiro, 1999 ). SPAD readings indicate degree of greenness of the plant, that correlates to amount of chlorophyll presen t ( Ntamatungiro, 1999 ). All plants in the study showed significant soil treatment effects on quality ratings at some point during the study. Composted treatments typically resulted in plants with higher quality ratings than t he non composted treatments. In instances when there were no statistical differences, visual differences in appearance may have still been observed in the field where plants grown in composted soils tending to have higher quality The lack of difference in quality ratings could be caused by human error, as the same people did not evaluate the plants every time and the ratings were based on personal judgment Linde and Hepner (2005) re ported Kentucky bluegrass grown in

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91 coarse loamy sand with compost addition outperformed one time fertilized plots in turfgrass color and density after 2 3 weeks. They attributed the observed difference in turf response, in part, to nutrients added to the soil in the compost. Landschoot and McNitt (2004) reported that compost source and rate of application greatly influenced turf establishment and that most compost treatme nts increased rate of Kentucky bluegrass establishment when compared to control plots. During the course of our study soil treatments affected plant nutrient content at some point for all plants. Warman et al. (2009) that the higher the application rate of a municipal solid w aste significantly increased the levels of N, P, and K in blueberry leaves in a sandy loam soil. In most cases the plant tissue nutrient content was higher for plants grown in compost amended soils when compared with those grown in unamended soils ; this f ollows the pattern for soil nutrient content in our study A study by Yavari et al. (2009) found that high concentration of N in soil often resulted in increased N concentration in plant tissues. However, p lant nutrient content in each species varied and was possibl y a re sult of differences in plant physiology that influenced the ability of plant to take up and use specific nutrients Grigatti et al. (2007) found that plant nutrient composition of four different plant species ( Begonia semperflorens, Mimu lus Salvia splendens, and Tagete patula ) varied within the species showing notable species differences in nutrient utilization as compost nutrient concentration increased. Similarly, a study by Wright et al. (2007a) suggested that the higher le vels of macronutrients in the tissue of Bermudagrass compared with St. Augustinegrass tissue were due to differences in plant uptake and absorption between the species when grown in compost amended soils

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92 CHAPTER 4 NUTRIENT LEACHING FROM SIMULATED RESI DENTIAL LANDSCAPES AS AFFECTED BY COMPOST AND TILLAGE Introduction Urban growth has been linked to water quality degradation and supply issues (Kaye et al., 2006) Urbanization of land results in disturbances to the soil profile, soil compaction and an increase in imp ervious cover, all of which can alter infiltration rates and other hydraulic properties of the soil. In turn, soil disturbances associated with urbanization directly affect surface runoff, erosion, and groundwater recharge (Defossez and Richard, 2002; Gregory et al., 2006; Hamilton and Waddington, 1999; Kaye et al., 2006) Runoff from urban areas is one of the leading sources of nutrients and ot her pollutants to surface waters (Shuman, 2004; USEPA, 2000) In fact, more than 50% of water bodies in Florida a re affected by urban non point source pollution, which includes pollution originating from residential landscapes (Association of State and Interstate Wa ter Pollution Control Administrators, 1984) Residential land is managed more intensively than agricultural land, which can result in greater losses of nitrogen and phosphorus from urban systems compared to agriculture (Bhattarai et al., 2008; Johnson et al., 2006) Once these nutrients are lost from residential landscapes, they have the potential to degrade surface and groundwater bodies (Erickson et al., 2005) Excess applications of N or P to the soil in fertilizers increase the potential for nitrate movement to groundwater and phosphate movement to surface waters (Confesor et al., 2007; Johnson et al., 2006) An increase in water, and fertilizer use is often a direct result of by the urban landowner a beautiful landscape (Hipp et al., 1993)

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93 The application of organic amendments (e.g., composted materials, manures) to soil is gaining favor as an en vironmental waste management strategy and a way to improve soil organic matter content in low fertility soils (Flavel and Murphy, 2006) However, the use of manure and compost as a nutrient source or soil amendment can also lead to pollution of water systems (Gille y and Eghball, 2002) When used in agricultural systems, organic amendments are often applied at rates that are based on N content of the material, an estimation of potential N mineralization, and crop requirement (Jaber et al., 2005) Application of organic amendments based on crop N requirements often results in applications of P that exceed crop requirements (Davis et al., 1997; Gaudreau et al., 2002) R e search has linked the degradation of water quality to increased losses of dissolved and particulate P from agricultural soils that received repeated applications of organic amendments based on crop N requirements (Sims et al., 1998) Hawver and Bassuk (2007) recommend well composted organic amendments be applied at a rate of >25% (>50% for loam or clayey soils) by volume to the top 46 cm of compacted urban soils to improve soil conditions. However, Urban (2008) suggest s that application of organic amendments to the top 30 cm of soils urban landscapes should not exceed 10 to 15% of the soil (by volume) to prevent subsidence. But app lications of 25 to 35% organic amendments by volume to the top 15 cm of soil have been suggested to increase soil biology and enhance the formation of topsoil in urban landscapes (Urban, 2008) These suggested rates for urban applications are likely to far exceed the N and P requirements of ornamental landsca pe plants. Both N and P have been shown to pose a risk to water quality at relatively low levels, ranging from

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94 0.01 to 0.035 mg L 1 for P and 10 mg L 1 for NO 3 (as set by EPA for human safety) (Erickson et al., 2001; Mallin and Wheeler, 2000) Nitrate leaching is a concern w hen high rates of compost with a low C to N ratio is applied to landscapes that are unable to utilize large amounts of N (Cogger, 2005) In addition, organic amendments are usually applied to the urban landscapes in addition to inorganic fertilizers, without taking into account the nutrient requirements of plants in the landscape (Gaudreau et al., 2002; Johnson et al., 2006) Tillage has also been suggested as a way to improve plant growth and quality in urban landscapes. Soil tillage can improve soil physical properties thereby improving the plant environment and allowing deeper root growth (Lipiec and Stepniewski, 1995) T illage breaks up soil aggregates creat ing more pore space thereby allowing water to infiltrate and roots to penetrate through the soil profile (Vogeler et al., 2005) Studies have shown that soil compaction can be alleviated by spike and core aeration and rototilling (Jim, 1993; Kozlowski, 1999; Unger and Kaspar, 1994) Deep tillage (to approximately 0.4 m) allows root growth into deeper soil horizons wit h more structur al development and greater water holding capacity (Busscher et al., 2006) However, it has been suggested that tillage practices have the potential to release greater amounts of NH 4 and NO 3 in surface runoff from agricultural soils than no till practices, as they compact the soil when machines run over the soil and decrease infiltration (Drury et al., 1993) Considerable inputs of water and fertilizers are needed to establish and maintain healthy, high quality turf (King et al., 2001) Turf dominated landscapes may receive yearly nitroge n and phosphorus applications in excess of 450 kg N ha 1 and 100 kg P

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95 ha 1 (Hipp et al., 1993). In Florida, turfgrass should receive 150 300 kg N ha 1 yr 1 when fertilized on a moderate maintenance schedule (Sartain, 2007) In contrast, the recommended N rate for o rnamentals on a moderate mai ntenance schedule in Florida is 97.6 kg N ha 1 yr 1 (Florida Yards and Neighborhoods Program, 2006). However, t urfgrass and mixed ornamentals generally receive similar rates of fertilization when they are situated in close proximity within the landscape (Saha et al., 2005). Elevated levels of N in watersheds is thought to be a result of fertilizer N runoff and leaching from originating from residential landscapes where turfgrass is routinely fertilized (Erickson et al., 2001) However, slower runoff velocities and increased infiltration of water are expected when turf is intensely managed (Gross et al., 1990) Research has suggested that adding organic amendments and tillage can help with plant establishment in urban landscapes. However, there is limited research that evaluates how these practices may affect nut rient losses in runoff or leachate from mixed residential landscapes The objectives of this study were to determine the effects of 1) compost additions and tillage or aeration and 2) vegetative cover (e.g. mixed ornamental species, turfgrass) on the pote ntial for nutrient losses in runoff or leachate from simulated urban landscapes. Materials and Method Experimental Design Twenty four mixed landscape plots (3.05 x 3.66 m ; 1.1 2 10 3 ha ) were established in a randomized complete block design at the UF IFAS Gulf Coast Research and Education Center in Wimauma, FL. All vegetation was removed from the site before plot construction. The entire research area was prepared at a 2% grade (as is typically required by construction codes) and compacted (bulk dens ity range: 1.7 1.9

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96 g cm 3 ) using a small plate compactor (Wacker Neuson, Munich, Germany). Individual landscape plots were constructed inside water sealed treated wooden boxes. Within each plot, the compacted field soil (Zolfo fine sand: sandy, siliceous hyperthermic Oxyaquic Alorthods (USDA NRCS, 2004) was then buried under 1.13 m 3 of un compacted soil fill material. Soil fill material was created by mi xing three fill soil residential construction. The three fill soil material sources included: a subsoil fill containing construction material and other debris; a clean topsoil material (St. Johns f ine sand; sandy, siliceous, hyperthermic Typic Alaquod) obtained from depth of 30 to 61 cm (Hills Dirt Pit, LLC., Riverview, FL), and a clean subsoil fill (St. Johns fine sand) fill obtained from a depth of 122 to 213 cm (Hill s Dirt Pit, LLC., Riverview, FL). Composted dairy manure solids (compost; Agrigy, Palm Harbor, FL) were applied as an organic soil amendment at a rate of 508 m 3 ha 1 ( approximately 256 Mg ha 1 ) in combination with two mechanical soil treatments (tillage and aeration) for a total of five soil management treatments. The soil management treatments were as follows: 1) tillage only, 2) compost only, 3) compost + tillage, 4) aeration only, 5) compost + aeration. In plots receiving the tillage treatment, soils were turned to a depth of 10 15 cm using counter rotating tines tiller (Sears Brands, LLC, Hoffman Estates, IL). In plots receiving the aeration treatment, soil aeration plugs were mechanically removed using a core aerator (Billy Goat Industries, Inc., L (no tillage or organic amendment) was included as the sixth soil treatment. Once soil treatments were applied, each plot was split and 5.58 m 2 of the plot was planted with Stenotaphrum secundatum (Walter) Kuntze (St. Augustine turfgrass); the

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97 remaining 5.58 m 2 was planted with mixed ornamentals. Mixed ornamentals species included Galphimia glauca Cav. (Thryallis), Rhaphiolepis indica (L.) Lindl. Ex Ker Gawl. (Indian hawthorne), Burfordi Lindl. & P axton (Buford holly), and Liriope muscari (Decne.) L. H. Bailey ( Liriope ). Turfgrass was fertilized at a total N rate of 220 kg ha 1 based on current UF IFAS recommendations (moderate maintenance schedule for South Forida ): 48.8 kg N ha 1 per application using Lesco Professional turf fertilizer (26 2 11) in February and October, 48.8 kg N ha 1 per application using polymer coated urea (42 0 ertilizer Solutions, Lakeland, FL) as a slow release N source in May and August, 24.4 kg N ha 1 with urea ( 46 0 0; Potash Corp., Northbrook, IL ) as a soluble N source, and 6.34 L ha 1 of ferrous sulfate (Sunniland Corporation, Sandord,FL ) in July (Sartain, 2007) Ornamental plants were fertilized every 3 months with urea at an N rate of 97.6 kg ha 1 based on UF IFAS recommendations for established woody ornamentals grow n in the landscape (Knox et al., 2002) The entire rese arch plot area was equipped with a spray irrigation system, which allowed for individual landscape plots to be irrigated as needed, based on UF IFAS recommendations (Zazueta et al., 2005) During establishment, plots were watered daily for 30 d after planting to allow for establishment of turf and ornamental plant mater ial. Irrigation frequency was then reduced to two days a week based on typical watering restrictions for landscape irrigation that would be mandated in times of drought (South Florida Water Management Distr ict, 2008; St. Johns River Water Management District, 2008) Irrigation was applied for 51 min (irrigation controller run time for two irrigation events per week at an application rate of 0.13 cm per hour, assuming system efficiency of 80% and considerin g effective rainfall) per plot on Mondays and Thursdays

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9 8 starting at 0 300 HR and ending around 0 900 HR Cumulative weekly rainfall data was collected from the Florida Automated Weather Network (FAWN) located within 50 m of the landscape plots (Figure 1) L eachate Collection and Analysis Each plot was outfitted with gutters to direct runoff from rain and irrigation events into collection containers at the bottom of the graded plots. Two 38 L capillary wick lysimeters (5 3 cm 3 6 cm) were also buried at a de pth of 15 25 cm below the soil surface in each plot to allow for leachate collection. Leachate samples were collected weekly and the volume was recorded. Leachate subsamples were collected for analysis every three months except during periods where rainf all produced significant volumes of leachate ( summer months ) (2, 3, 4, 5, 6, 7, 14, 18, 21, 24, 27, 32, 42, 55 weeks after treatment [WAT]). The leachate subsamples were passed through a 0.45 m filter and stored at 4C until analysis. Leachate pH was me asured using a combination electrode and electrical conductivity (EC) was analyzed using an EC meter. Leachate samples were analyzed colorimetrically for NO 3 + NO 2 (USEPA, 1993a), NH 4 (USEPA, 1983) and dissolved phosphorus (USEPA, 1993b) using a discrete analyzer (Seal Analytical, Wes t Sussex, UK) The volume of leachate collected in each collector was adjusted based on the land area (2.11 x 10 5 ha) drained to each collector. Nutrient load was then calculated by multiplying the area adjusted leachate volume by the nutrient concentra tion. Data Analysis The experiment was designed as randomized complete block split plot design with 4 blocks and 6 soil treatments in each block. Half of each plot was planted with ornamental plants and the other was planted with turfgrass as describe d previously.

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99 The soil treatments within each block were assigned randomly. Data were analyzed using the PROC MIXED procedures in SAS with soil treatment as a fixed effect and block as a random effect (SAS Institute, 2003) Leachate volume EC, NO 3 + NO 2 NH 4 and dissolved P data were log transformed prior to statistical analysis. All comparisons were completed using the Tukey honestly significant difference ( HSD ) test with a Results and Discussion Leachate and Runoff Volume Most of the landscape plots produced no measurable runoff during the entire study period. Runoff was only collected at 16 WAT (June 2008) from five plots receivi ng the compost only (3) or compost + aeration (2) treatments; the average volume of runoff collected from these landscape plots was 1.02 L. This runoff event occurred during the rainy season (Figure 4 1) and it was probably a result of soil saturation fro m a previous rainfall event. A similar study by Erickson et al. (2001) measured only one runoff event from simulated landscapes constructed o n a 10% slope in a sandy soil in southern Florida despite frequent intense rainfall events occurring throughout the study Our study did not account for the proportion of land area at a residential home site that would be covered with impervious surfaces (e.g., roof, driveway, sidewalks, etc.). The presence of these impervious surfaces would essentially increase the volume of rainfall that would be delivered to the landscaped areas. It is probable more runoff events would have been reported from our plot s if a portion of the plot was covered with impervious surfaces. The volume of leachate collected from the landscape plots was influenced by irrigation, time of year, and rainfall received. The landscape plots received 5.72 cm of

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100 irrigation per week, spli t into two applications, during the initial plant establishment period (30 days) and 2.16 cm of irrigation per week throughout the remainder of the study based on UF IFAS recommendations (Zazueta et al., 2005) Higher leachate volumes were collected from landscape plots in the summer months (12 28 WAT) due to the higher amount of rainfall (Figures 4 1 and 4 2). Soil treatments (e.g., compost, tillage, and aeration) had no effect on the volume of leachate collected at any date during the study (Figure 4 2). This could be due to the high sand content and low clay content that is common in Florida soils. Even though our soil was compacted at a depth of 10 cm the mean soil bulk density reported was 1.42 g cm 1 which is considered to an be an ideal bulk density for sandy soils and is well below the 1.8 g cm 1 bulk density threshold for root restriction (Hanks and Lewandowski, 2003). There was, however, a vegetative cover effect on the volume of leachate collected between 16 52 WAT. Generally, higher leachate volumes were collected from under ornamentals (mean = 60221 L ha 1 ) than under turfgrass (mean = 30421 L ha 1 ). While our study found an effect of vegetative cover on leachate volume, Erickson et al. (2005) reported no significant differences in leachate volume from mixed ornamental cover (e.g., groundcovers, woody shrubs, and trees; 3,437 mm) compared with a monoculture of turfgrass (3,802 mm) in simulated mixed landscapes in South Florida, when both were irrigated as needed to avoid wilt. The higher leachate volumes collected under mixed ornamentals in our study co uld be due to the fact that the canopy of the ornamental plants did not cover the entire plot and that these plants had a lower root density than the turf. Erickson et al. (2008) noted that root biomass was significantly greater for St. Augustinegrass mon oculture than for mixed ornamental species in the

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101 landscape. Higher leachate volumes could also be the result of over irrigatin g the ornamentals. Previous studies suggested that many ornamental plants will exhibit acceptable growth and quality once estab lished when irrigation is significantly reduced (e.g., <50% of reference evapotranspiration) (Montague et al., 2007; Pittenger et al., 2001; Staats and Klett, 1995) Figure 4 1. Actual week ly rainfall and irrigation appli ed to simulated residential landscapes established in a sandy soil in Balm, Florida

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102 Figure 4 2. Mean l eachate volume from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass Leachate pH and Electrical Conductivity Leachate pH was not affected by soil treatment o r vegetative cover (data not shown). The pH ranged from 5.11 to 9.09 throughout the study. The pH of the leachate was likely a factor of the soil pH, which varied as a result of soil treatments. Landscape plots receiving compost had a mean pH of 7.29, wh ile uncomposted plots had a mean pH of 6.59. The irrigation water used in the study had a pH of 7.83. There is also a trend for higher leachate pH during times where significant rainfall was reported (12 28 WAT) (Figure 4 1). Electrical conductivity valu es in leachate from plots amended with compost typically exhibited higher EC values (0.22 to 0.73 dS m 1 ) than the unamended plots (0.17 to 0.54 dS m 1 ). However, results were significant at 5 and 6 WAT only, when composted treatments had significantly hi gher EC than non composted treatments

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103 (Figure 4 3). At 21 and 24 WAT, plots that received compost + aeration treatments had significantly higher EC than unamended soils. After 27 WAT, there is no longer any soil treatment effect on leachate EC. Similar results were reported for soil EC (Table 2 9). The elevated EC in leachate collected from composted soils is likely due to the presence of soluble salts in the composted dairy manure solids (EC = 1.02 dS m 1 ) that were applied. These salts were leached f rom the landscape plots with repeated application of rainfall and irrigation. Figure 4 3. Mean electrical conductivity (EC) of leachate samples collected from simulated residential landscape plots where sandy fill soils received compost, tillage and/or a eration soil treatments. Star (*) indicates a significant difference (P <0.05) between composted treatments and non composted treatments. Plus sign (+) indicates a significant difference (P <0.05) between compost + aeration and non composted treatments

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104 Dissolved Phosphorus Leachate P concentrations ranged from 0.0 8 to 0.52 mg L 1 Soil treatments (compost, tillage, aeration) and vegetative cover had no affect on P concentrations in leachate (Figure 4 4). Toth et al. (2006) reported no significant differences in leachate total P when c orn or alfalfa grown in a silt loam soils received inorganic fertilizer, dairy manure, or no nutrient source; however the highest annual mean leachate total P concentrations (0.18 to 0.19 mg L 1 ) were collected from manure amended soils. There was no soil treatment effect on P load; however, there was a vegetative cover effect on P load from 18 WAT through the completion of the study ( Figure 4 5) Phosphorus load was higher under ornamental cover ( 21.8 g ha 1 ) compared with turf cover ( 11.7 g ha 1 ). This was a direct result of the higher volume of leachate collected under ornamental plant cover (Figure 4 2). A study by Erickson et al. (2005) found greater P and K leaching from mixed ornamentals that were fertilized during establishment, than St. Augustine turfgrass that was routinely fertilized, with the greatest concentrations reported during periods of high drainage. Reed et al. (2006) reported a decrease (not statistically significant) in P movement through the soil when biosolids, clean organic w aste, and Bedminster composts (contains 75% municipal solid waste and 25% biosolids) were applied to a Krome (loamy skeletal, carbonatic, hypertermic, Lithic Udorthents) soil in south Florida. The decrease of P movement following compost applications coul d be due to the presence of organic matter in the compost which increase d the ability to sorb P Another possibility of P loss could be attributed the decrease in P leaching to P association with soil cations such as Fe, Al, and Ca (Reed et al., 2 006 ).

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105 Figure 4 4. Mean concentration of dissolved phosphorus from 0 52 weeks after treatment (WAT) in leachate collected from simulated residential landscapes in Florida where soils were amended with composted dairy manure solids. Figure 4 5. Mean P load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass.

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106 Leachate Nitrate (+ Nitrite) There were soil treatment and vegetative cover effects on the concentration of NO 3 + NO 2 in the leachate samples between 2 7 WAT (Figure 4 6 ). From 2 to 5 WAT, compost amended soils leached more NO 3 + NO 2 than unamended soils. By 6 WAT, plots where compost was tilled into the soil were no longer pro ducing higher leachate NO 3 + NO 2 concentrations than the unamended soils. We likely see higher NO 3 + NO 2 concentrations at the beginning of the project because the NO 3 was leaching out from the compost (original compost samples reported NO 3 <4.00 mg kg 1 ) In contrast, Jaber et al. (2005) found no differences for approximately a year and a half, in leachate NO 3 + NO 2 concentrations when yard and food waste compost, biosolids compost, municipal solid waste biosolids compost, or an inorganic N fertilizer were applied to a sandy, calcareous soil. According to Burgos et al. (2006), NO 3 leaching is normally high when stabilized organic materials rich in N are applied, but loss of NO 3 in soils treated with composted materials is usually very low. Vegetative cover effects on NO 3 + NO 2 leachate concentrations were seen at 5, 6, 14 and 18 WAT. In all cases, NO 3 + NO 2 concentrations in leachate were higher when collected under ornamental plant cover than under turf (Figure 4 7 ). By 21 WAT, there was no longer any soil treatment or vegetative cov er effects on concentrations of NO 3 in leachate. Higher concentration of NO 3 + NO 2 collected under the ornamentals is likely due to the root density of the ornamental plants. Erickson et al. (2008) noted that root biomass was significantly greater for St. Augustine turf grass monoculture than for mixed ornamental species in the landscape after one year; which was the timeframe of our study. The differences in root biomass could affect nutrient uptake and well as infiltration rates which in fluence the concentration of NO 3 in leachate moving through

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107 the soil profile. Immediately after installation, the roots of ornamental plants are confined to the planting hole. As a result, there is a large volume of soil in ornamental plant beds that do e s not contain roots until the plants begin actively send roo ts laterally from the plant base. Therefore, it is likely that when fertilizers or compost are broadcast on the soil surface, some of the NO 3 + NO 2 will be subject to leaching as it was applied i n areas where plant roots are not available to intercept the nutrients. Brauen and Stahnke (1995) reported that NO 3 from nitrogen fertilizers moved freely through a pure sand rooting medium during turf establishment from seed when there were few roots, no thatch and no organic matt er accumulation. Nitrate load was affected by soil treatment only at 3 WAT, when NO 3 loads from the plots receiving the compost only or the compost + aeration treatments were significantly higher than loads from the plots receiving all other treatments. H owever, there was a significant vegetative cover effect on NO 3 + NO 2 load at 18, 27, 32, and 42 WAT; where the NO 3 + NO 2 load was higher from ornamentals than turf. This was due to the higher volume of leachate collected under ornamental cover (Figure 4 2 ), which could be a result of overwatering or limited root spread. Erickson et al. (2001) also found that losses of N concentration (both NO 3 and NH 4 ) were higher from mixed ornamentals than St. Augustine turfgrass which indicate s that turfgrass may be more efficient at N utilization than woody ornamentals Mangiafico and Guillard (2006) found greater concentrations of NO 3 in leachate during turfgrass establishment from sod and attributed it to mineralization that was stimulated by soil disturbance during planting ; once turf was established NO 3 losses were reduced. Cisar et al. (2004) hypothesized

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108 that as the landscape continues to develop N leaching would be greatly reduced for both turf and ornamentals Figure 4 6 Mean concentration of nitrate in leachate collected from simulated residential landscapes in Florida where soils were amended with composted dairy manure solids.

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109 Figure 4 7 Mean concentration of nitrate in leachate collected from simulated residential landscapes in Florida planted with mixed ornamentals and St. Augustine turfgrass. Figure 4 8. Mean nitrate load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass.

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110 Leachate Ammonium The concentration of NH 4 in leachate was affected by soil treatments from 18 through 42 WAT. In general, NH 4 concentrations in leachate collected from soils receiving one or more of the treatments where compost was applied were significantly higher than in leachate collected from unamended soils (Figure 4 9 ). Vegetative cover effects on NH 4 concentration in leachate were significant at 18 and 21 WAT only. At both sampling dates, leachate NH 4 concentrations were higher under ornamental cover when compared with NH 4 leached from turf. Ammonium concentrations were highest between July and September (12 28 WAT), which corresponds with high rainfall amounts (Figure 4 1) and warm temperatures ( warm season lasting May to August with temperatures ranging from 20.6 to 32.5 C ). Under these conditions, microorganisms in the soil are actively mineralizing organic N (from the compost and soil organic matter) into NH 4 (Brady and Weil, 2002) We hypothesize that this mineralized N is then lost in leachate due to concentrations that exceed plant requirements or due to low soil sorption capacity, high rainfall and, in the case of ornamentals, low root density. Soil treatment effects on NH 4 load were significant at 18, 21, 27, and 32 WAT (Figure 4 10) At 18 WAT, leachate NH 4 load was significan tly higher from the plots receiving the compost + aeration treatment then from unamended soils. Compost only and compost + aeration soil treatments led to higher NH 4 loads in leachate than the aeration only treatment at 32 WAT and the control or tillage o nly t reatments at 21, 27 and 32 WAT. Ammonium loss from composted treatments could likely be reduced if inorganic N fertilizer was not applied in conjunction with compost Leachate NH 4 load was affected by vegetative cover only at 18 and 21 WAT. As was reported for NO 3

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111 load, the increase in NH 4 load under ornamentals was related to the increased volume of leachate collected under the ornamental plant cover. Figure 4 9 Mean concentration of ammonium in leachate collected from simulated residential la ndscapes in Florida where soils were amended with composted dairy manure solids. Figure 4 10. Mean ammonium load from 0 52 weeks after treatment (WAT) collected from simulated residential landscape plots planted with mixed or namentals and St. Augustine turfgrass.

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112 CHAPTER 5 CONCLUSIONS Soils are often drastically disturbed during residential construction, resulting in inadequate conditions for landscape establishment. Results f rom our study indicate that the addition of comp ost (or other organic amendments) to soils can improve soil physical and chemical properties in residential landscapes when fill soils are used. Application of compost will also enhance the establishment and improve growth and quality of selected o rnament al landscape plants. However, it appears that the topdressing with compost will enhance plant growth and quality as well, if not better, than when the material was incorporated to a depth of 20 cm by tillage. In contrast, it appears that shallow tillage and aeration have little effect on measured soil properties; results may have been different if finer textured soils had been evaluated, where the threshold for bulk density above which root growth would be compromised are lower. Similarly there were no significant effects of aerating the soil on plant establishment, growth, or quality. Over the course of one year, the use of compost as a soil amendment in a simulated residential landscape did result in an increase in N losses in leachate. Most NO 3 + N O 2 losses occurred immediately after application of compost, while mineralization of organic N increased NH 4 losses during the summer months. Nutrient losses in leachate under ornamental cover were highest during the first few months of establishment, whe n the root density was limited and large amounts of rainfall were received. Since the addition of compost helps increase plant quality but does increase nutrient load to the system, using it as an addition to new residential lawns can be recommended, but only if the use of inorganic fertilizers is reduced. However, there are

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113 concerns that recommendations for one time application of organic amendments at a rate of 25 35% by volume to the top six inches of soil may lead to significant N losses, especially w ith low C:N ratios. In contrast, if the organic material has a high C:N ratio, it is possible that applications at this rate could lead to N immobilization at the detriment of the plant material. While the results of this study can only show the benefit s of compost additions during the first year after planting, data indicates that applications of compost may prevent plant failure, which results in less money and time dedicated to residential landscapes. Future research should determine if improved plan t growth in composted amended soils was a result of additional nutrients added to the soil in the compost or due to the improvements in soil conditions. Future research should also evaluate the long term effects of compost addition after plant establishme nt period. Also, more research needs to be conducted to determine if an increase in root density for ornamental plants will reduce the potential for N losses in leachate when compost and fertilizers are applied in the landscape.

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114 APPENDIX A ADDITIONAL SOI L ANALYSIS Particle Size Analysis All soils were classified as a loamy sand or sand, according the soil textural triangle (Tables A 1 and A 2) Soil particle size was determined by using the particle size was determined by the hydrometer method (Bouyoucos, 1962) There were no significant changes in soil composition throughout the stud y; the soils were predominantly sand (averaged 88.22%), with very little silt (5.48%) and little clay (6.30%).

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115 Table A 1. Particle size distribution of fill soil samples (0 10 cm depth) collected from simulated residential landscape plots planted with mi xed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT % Sand Control 88.6 85.4 91.2 87.5 90.8 Tillage Only 90.6 86.7 91.2 87.7 89.7 Compost Only 87. 8 83.8 90.7 84.8 89.0 Compost + Tillage 89.2 84.4 89.3 86.2 89.6 Aeration Only 89.9 85.8 91.5 88.0 89.4 Compost + Aeration 89.5 83.5 90.6 86.4 89.3 Silt Control 7.30 9.26 3.01 4.04 3.74 Tillage Only 6.28 7.70 3.33 5.60 4.16 Compost Only 6.28 7.16 3. 64 4.44 4.47 Compost + Tillage 7.30 8.24 3.95 3.95 3.53 Aeration Only 6.90 8.73 3.95 7.75 5.09 Compost + Aeration 6.68 8.64 3.33 4.44 4.47 Clay Control 4.15 5.39 5.80 8.45 5.43 Tillage Only 3.09 6.63 5.49 6.68 6.17 Compost Only 5.90 9.06 5.70 10.8 6.59 Compost + Tillage 3.52 7.35 6.75 9.90 6.92 Aeration Only 3.20 5.49 4.57 7.22 5.55 Compost + Aeration 3.84 7.90 6.13 9.20 6.26

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116 Table A 2. Particle s ize d istribution of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT % Sand Control 90.7 87.7 94.2 90.8 90.3 T illage Only 90.0 87.7 94.8 89.9 91.2 Compost Only 89.1 85.2 92.7 89.5 89.9 Compost + Tillage 90.4 86.8 92.8 88.8 88.9 Aeration Only 90.6 87.8 95.4 90.2 90.5 Compost + Aeration 91.4 87.3 93.2 89.1 90.4 Silt Control 7.08 7.39 3.33 4.89 5.51 Tillage On ly 7.30 6.45 3.33 5.20 6.76 Compost Only 6.99 7.39 3.01 5.51 6.76 Compost + Tillage 6.76 7.39 2.71 5.20 6.66 Aeration Only 7.08 7.08 3.01 4.89 6.14 Compost + Aeration 7.30 7.39 3.01 5.20 5.82 Clay Control 2.28 4.97 2.49 4.27 4.18 Tillage Only 2.69 5 .82 1.87 4.90 2.09 Compost Only 3.92 7.38 4.25 5.00 3.34 Compost + Tillage 2.81 5.79 4.57 6.04 4.49 Aeration Only 2.35 5.18 1.55 4.90 3.34 Compost + Aeration 1.32 5.31 3.84 5.73 3.76 Bulk Density Soil bulk density under o rnamentals at 10 20 cm was affected by soil treatments at 13 and 52 WAT only (Table A 3). At 13 and 52 WAT, soil bulk density was significantly

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117 lower when compost was tilled to a depth of 15 cm compared with soils where no compost was applied. These resu lts are likely due to the fact that surface applications of compost did not impact soil bulk density at the 10 20 cm soil depth, while tillage of compost to 15 cm was able to reduce bulk density under ornamentals. Soil bulk density under turf was not impa cted by soil treatment (Table A 4 ). Table A 3. Bulk density of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals at four sampling dates. Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Treatment 13 WAT 27 WAT 40 WAT 52 WAT g cm 3 Control 1.79a 1.63a 1.75a 1.76a Tillage Only 1.76a 1.79a 1.72a 1.60a Aeration Only 1.69ab 1.73a 1.70a 1.77a Compost Only 1.66ab 1.54a 1.63a 1.54ab Compost + Tillage 1.51b 1.56a 1.55a 1.40b Compost + Aeration 1.64a b 1.56a 1.70a 1.68a

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118 Table A 4. Bulk density of fill soil samples (10 20 cm depth) collecte d from simulated residential landscape plots planted with St. Augustine turfgrass at five sampling dates. Treatment 13 WAT 27 WAT 40 WAT 52 WAT g cm 3 Control 1.64a 1.39a 1.49a 1.60a Tillage Only 1.75a 1.62a 1.58a 1.57a Aeration Only 1.73a 1.63a 1.46a 1.52a Compost Only 1.64a 1.52a 1.47a 1.52a Compost + Tillage 1.73a 1.53a 1.36a 1.47a Compost + Aeration 1.62a 1.50a 1.56a 1.43a Values within the same sampling date (WAT) with the sa me letter are not significantly different at P < 0.05 using Tukey's HSD test. Soil Organic Matter At the 10 20 cm depth, soil organic matter content was influenced by soil treatment at 13 and 52 WAT only (Table A 5). At 13 WAT, soils amended with compost had significantly higher organic matter (OM) content compared with soils receiving the control and tillage only treatments; soils receiving the aeration only treatment had significantly lower OM content than soils receiving the compost + tillage treatment By 52 WAT, there was a significant difference between soils receiving the compost + tillage and tillage only treatments. Overall, composted soils maintained a higher OM content (9 23 g kg 1 ) than the non composted treatments (1 13 g kg 1 ).

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119 Table A 5 Soil organic matter of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT g kg 1 Control 9 0 0 a 1 1 5a 4 5 0 a 4 5 0 a 1 0 5ab Tillage Only 9 0 0 a 1 2 0a 1 0 0 a 5 5 0 a 8 5 0 a Aeration Only 1 0 5a 1 3 0a 1 0 0 a 8 0 0 a 1 0 5ab Compost Only 9 0 0 a 2 0 0b 1 0 0a 9 0 0 a 1 5 5ab Compost + Tillage 9 5 0 a 1 8 5b 9 0 0 a 1 0 6a 14 0b Com post + Aeration 9 0 0 a 2 3 1b 1 2 0a 1 5 6a 16 0ab Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Electrical Conductivity Soil treatments affe cted EC at 10 20 cm at 13 and 27 WAT only. At 13 WAT, the soils receiving the compost only treatment had significantly higher EC than soils receiving the other treatments (Table A 6) At 27 WAT, soils receiving the compost only and compost + aeration tre atments had significantly higher EC than non composted plots. The increase in EC in composted soils is likely due to the leaching of salts that were added with the compost through the soil profile. These effects disappear by 40 WAT after large rainfall e vents removed most of the salts from the root zone.

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120 Table A 6 Electrical conductivity (EC) of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampl ing dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT s cm 1 Control 454a 2 20 ab 173a 837a 334a Tillage Only 481 a 187a 1 60 a 594 a 297a Aeration Only 496 a 195 a 164 a 763a 426a Compost Only 519a 301 b 328b 591a 422a Compost + Tillage 534 a 263ab 331ab 69 3 a 357a Compost + Aeration 441 a 24 8 ab 247b 71 5 a 261a Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test. Field Moisture Capacity The field moisture capacity at the 10 20 cm depth was not influenced by soil treatment throughout the duration of the study (Table A 7) Table A 7 Field moisture capacity of fill soil samples (10 20 cm depth) collected from simula ted residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT % Control 8.12a 22.82a 11. 4 a 11.2 a 15. 3 a Tillage Only 8.12a 9.50a 10.0a 10.0a 10.6 a Aeration Only 8.52a 12.4 a 12.4 a 12.4a 11.5 a Compost Only 10. 1 a 20. 8a 12.1 a 12.3a 12.0a Compost + Tillage 8.26a 10.5a 11.6 a 11.6a 11.0a Compost + Aeration 8.91a 10.7a 12 .2 a 12.2a 15.6 a Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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121 Mehlich 1 Nutrients Phosphorus concentrations at the 10 20 cm depth were affected by soil treatments from 13 WAT through 52 WAT. At 13 WAT, soils receiving the compost only treatment had higher concentrations of P than the control plots (Table A 8) At 27 WAT, the compost + aeration treatment resulted in higher P concentrations than the non composted treatments. At 40 WAT, all com posted soils had higher P concentrations than soils receiving the control treatment. At 52 WAT, the compost only treatment resulted in higher P concentrations than the tillage only treatment. These results suggest that some of the P applied in compost wa s moving downward through the soil profile. Soil test K concentrations at 10 20 cm depth were significantly higher for the composted treatments compared with the non composted treatments at 27 WAT only (Table A 8) This suggests that K added in compost wa s leaching downward through the soil profile. At the 10 20 cm depth, significant soil treatment effects were reported for soil Mg concentration at 13 and 27 WAT (Table A 8) At 27 WAT, compost only and compost + aeration treatments had higher Mg concentra tions than non composted soils. At 40 WAT, the compost + aeration plots had significantly higher soil Mg than soils receiving the tillage only treatment. Soil Ca concentrations at 10 20 cm depth were affected by soil treatments at 13, 27 and 52 WAT (Tabl e A 8) At 13 WAT, composted soils had higher Ca concentrations than unamended soils. At 27 WAT, the compost only and compost + aeration treatments maintained higher soil Ca than the non composted treatments. At 52 WAT, the compost only treatment led to higher soil Ca than the non composted treatments.

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122 Table A 8 Mehlich I nutrient content (mg kg 1 ) of fill soil samples (10 20 cm depth) collected from simulated residential landscape plots planted with mixed ornamentals and St. Augustine turfgrass at five sampling dates. Treatment 0 WAT 13 WAT 27 WAT 40 WAT 52 WAT mg kg 1 Phosphorus Control 94. 4 a 128 a 129a 131 a 151ab Tillage Only 101 a 13 7 5ab 125a 152ab 137a Compost Only 11 9 a 17 9 b 164ab 197b 189b Compost + Tillage 99. 7 a 17 7 6ab 153ab 18 8 b 16 2 ab Aeration Only 11 5 a 1 70 ab 141a 168ab 161ab Compost + Aeration 1 20 a 17 4 ab 181b 188b 169ab Potassium Control 6.55a 12. 8a 11. 8a 14. 3 a 10. 7 a Tillage Only 7.45a 12. 6 a 10. 9a 13. 3a 15. 6a Compost Only 8.10a 30. 0b 16. 5a b 22. 4a 12. 6 a Compost + Tillage 9.78a 30. 7b 16. 9 ab 22. 4a 12. 6a Aeration Only 7.15a 15. 8a 13. 3a 16. 9a 11. 8 a Compost + Aeration 9.40a 32. 9b 23. 2b 16. 9a 14. 9a Magnesium Control 345a 1784a 1498ab 1730a 1570a Tillage Only 343a 1611a 1120a 1712a 1426a Com post Only 4 30 a 3131b 1600ab 2571a 2200a Compost + Tillage 352a 2452ab 1518ab 2158a 1713a Aeration Only 44 3 8a 1916a 1602ab 1952a 2151a Compost + Aeration 431 a 3206b 2131b 2020a 1918a Calcium Control 15. 5a 49. 4a 56. 1 ab 95. 9 a 60. 3 a Tillage Only 16. 4 a 49 1 a 49. 3a 75. 8a 64. 3 a Compost Only 21. 9 a 11 8 b 90. 7 ac 130a 93. 5 b Compost + Tillage 17. 4a 128b 73. 1ab 11 8 a 70. 7 ab

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123 Aeration Only 25. 0a 53. 5a 56. 2ab 77. 9a 67. 4a Compost + Aeration 20. 2 a 12 4 b 111c 109a 83. 5 ab Aluminum Control 42. 5a 38. 5a 42. 3a 42. 0a 45. 2 a Tillage Only 44. 2 a 46. 1a 44. 4 a 50. 8a 47. 8a Compost Only 44. 3 a 40. 6 a 43. 3 a 44. 5 a 44. 7 a Compost + Tillage 42. 7a 40. 6 a 42. 8a 46. 6 a 47. 1a Aeration Only 46. 6 a 42. 0a 42. 9 a 47. 3a 45. 1a Compost + Aeration 42. 4a 39. 4a 41. 5 a 43. 1a 45. 6 a Iron Control 288a 53 7 a 578a 660a 53 2 a Tillage Only 29 6 a 645a 628a 621a 578a Compost Only 331a 976a 67 7 a 72 9 a 673a Compost + Tillage 28 9 a 578a 56 8 a 593a 561a Aeration Only 318a 6 30 a 610a 61 5 a 597a Compost + Aeration 310a 74 9 a 744a 714a 655a Sodium Control 5.91a 12. 1 a 13. 7 a 11. 9a 10. 6 a Tillage Only 5.85a 12. 1 a 12. 7a 12. 3 a 10. 2a Compost Only 5.76a 15. 9a 15. 1a 13. 9a 13. 3a Compost + Tillage 5.63a 15. 5a 14. 0a 14. 6 a 12. 2 a Aeration Only 5.69a 14. 7 a 13. 8a 13. 4a 12. 2 a Compost + Aeration 5.94a 17. 5a 17. 9a 12. 1 a 11. 8 a weeks after treatment Values within the same sampling date (WAT) with the same letter are not significantly different at P < 0.05 using Tukey's HSD test.

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124 LIST OF REFERENCES Aggelides, S.M., and P.A. Londra. 2000. Effects of compost produced from town wastes and sewage sludge on the physical properties of a loamy and clay soil. Bioresour. Technol. 71:253 259. Albiach, R., R. Canet, F. Pomares, and F. Ingelmo. 2001. Organic matter components and aggregate stability after the applicatio n of different amendments to a horticultural soil. Bioresour. Technol. 76:125 129. Association of State and Interstate Water Pollution Control Administrators. 1984. America's clean water: The state's evaluation of progress 1972 1982: Appendix. Washington, D.C. Bai, X., K.M. Ma, L. Yang, and X.L. Zhang. 2008. Simulating the impacts of land use changes on non point source pollution Lugu Lake watershed. Int. J. Sustainable Development World Ecol. 15:18 27. Beemster, G., and J. Masle. 1996. Effects of soil resi stance to root penetration on leaf expansion in wheat ( Triticum aestivum L. ): composition, number and size of epidermal cells in mature blades. J. Exp. Bot. 47:1651 1662. Bhattarai, G., P. Srivastava, L. Marzen, D. Hite, and U. Hatch. 2008. Assessment of e conomic and water quality impacts of land use change using a simple bioeconomic model. Environ. Management 42:122 131. Blake, G.R., and K.H. Hartge. 1986. Bulk density, In G. S. Campbell, et al., eds. Methods of Soil Analysis, Part 1: Physical and Mineral ogical Methods. Soil Science Society of America, Madison, WI. Bockheim, J.G. 1974. Nature and properties of highly disturbed urban soils. Soil Science Society of America, Philadelphia, PA. Bouwer, H. 1986. Intake rate: Cylinder infiltrometer, In A. Klute, ed. Methods of Soil Analysis Part 1: Physical and Mineralogical Methods. Soil Science Society of America, Madison, Wisconsin. Bouyoucos, G.J. 1962. Hydrometer method improved for making particle size analy ses of soils. Agron. J. 54:464 Brady, N.C., and R. R. Weil. 2002. The Nature and Properties of Soils. 13th ed., Upper Saddle River, New Jersey. Brauen, S., and G. Stahnke. 1995. Leaching of nitrate from sand putting greens. United States Golf Association 33:29 32. Busscher, W.J., J.M. Novak, P.G. Hunt, and P.J. Bauer. 2006. Increase of soil strength over time in a US southeastern coastal plain loamy sand. Soil Sci. 171:519 526.

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125 Cisar, J.L., J.E. Erickson, G.H. Snyder, J.J. Haydu, and J.C. Volin. 2004. Documenting nitrogen leaching and runoff losses from urb an landscapes, p. 161 179 Environmental Impact of Fertilizer on Soil and Water, Vol. 872. Cogger, C., R. Hummel, J. Hart, and A. Bary. 2008. Soil and Redosier dogwood response to incorporated and surface applied compost. HortScience 43:2143 2150. Cogger, C .G. 2005. Potential compost benefits for restoration of soils disturbed by urban development. Compost Sci. Utilization 13:243 251. Collins, J.P., A. Kinzing, N.B. Grimm, W.F. Fagan, D. Hope, J. Wu, and E.T. Borer. 2000. A new urban ecology. Am. Scientist 8 8:416. Confesor, R.B., J.M. Hamlett, R.D. Shannon, and R.E. Graves. 2007. Movement of nitrogen and phosphorus downslope and beneath a manure and organic waste composting site. Compost Sci. Utilization 15:119 126. Craul, P.J. 1985. A description of urban so ils and their desired characteristics J. Arboriculture 11:330 339. Craul, P.J. 1994. Soil compaction on heavily used sites. J. Arboriculture 20:69 74. Curtis, M.J., and V.P. Claassen. 2009. Regenerating topsoil functionality in four drastically disturbed s oil types by compost incorporation. Restoration Ecol. 17:24 32. da Silva, A.P., B.D. Kay, and E. Perfect. 1997. Management versus inherent soil properties effects on bulk density and relative compaction. Soil Tillage Res. 44:81 93. Davis, J.G., B. Ahnstedt and M. Young. 1997. Soil characteristics of cropland fertilized with feedlot manure in the South Platte River Basin of Colorado. J. Soil Water Conserv. 52:327 331. Defossez, P., and G. Richard. 2002. Models of soil compaction due to traffic and thier eva luation. Soil Tillage Res. 67:41 64. Drury, C., D. McKenney, W. Findlay, and J. Gaynor. 1993. Influence of tillage on nitrate loss in surface runoff and tile drainage. Soil Sci Soc Am J 57:797 802. Dukes, M. 2008. Summary of IFAS turf and landscape irrigat ion recommendations [Online]. Available by University of Florida Institute of Food and Agricultural Sciences http://edis.ifas.ufl.edu/AE436 (verified 12 October 2009). Eghball, B. 1999. Liming effects of be ef cattle manure or compost. Commun. Soil Sci. Plant Anal. 30:2563 2570.

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126 Eghball, B. 2002. Soil properties as influenced by phosphorus and nitrogen based manure and compost applications. Agron. J. 94:128 135. Eghball, B., and J.F. Power. 1999. Phosphorus and nitrogen based manure and compost applications: Corn production and soil phosphorus. Soil Sci. Soc. Am. J. 63:895 901. Erickson, J.E., J.L. Cisar, J.C. Volin, and G.H. Snyder. 2001. Comparing nitrogen runoff and leaching between newly established St. Augustinegrass turf and an alternative residential landscape. Crop Sci. 41:1889 1895. Erickson, J.E., J.L. Cisar, G.H. Snyder, and J.C. Volin. 2005. Phosphorus and potassium leaching under contrasting residential landscape models established on a sandy soi l. Crop Sci. 45:546 552. Erickson, J.E., J.L. Cisar, G.H. Snyder, D.M. Park, and K.E. Williams. 2008. Does a mixed species landscape reduce inorganic nitrogen leaching compared to a convential St. Augustinegrass lawn? Crop Sci. 48:1586 1594. Ervin, E.H., a nd A.J. Koski. 2001. Kentucky Bluegrass growth respones to trinexapac ethyl, traffic, and nitrogen. Crop Sci. 41:1871 1877. Flavel, T.C., and D.V. Murphy. 2006. Carbon and nitrogen mineralization rates after application of organic amendments to soil. J. En viron. Qual. 35:183 193. Florida Yards and Neighborhoods Program. 2006. A guide to Florida friendly landscaping: Florida Yards & Neighborhoods Program. 3rd ed. University of Florida, IFAS, Gainesville, FL. Gaudreau, J.E., D.M. Vietor, R.H. White, T.L. Prov in, and C.L. Munster. 2002. Response of turf and quality of water runoff to manure and fertilizer. J. Environ. Qual. 31:1316 1322. Gilley, J.E., and B. Eghball. 2002. Residual effects of compost and fertilizer applications on nutrients in runoff. Trans. AS AE 45:1905 1910. Ginting, D., A. Kessavalou, B. Eghball, and J.W. Doran. 2003. Greenhouse gas emissions and soil indicators four years after manure and compost applications. J. Environ. Qual. 32:23 32. Glab, T. 2007. Effect of soil compaction on root syste m development and yields of tall fescue. Int. Agrophysics 21:233 239. Gregory, J.H., M.D. Dukes, P.H. Jones, and G.L. Miller. 2006. Effect of urban soil compaction on infiltration rate. Journal of Soil and Water Conservation 61:117 124.

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127 Grigatti, M., M.E. Giorgioni, and C. Ciavatta. 2007. Compost based growing media: Influence on growth and nutrient use of bedding plants. Bioresour. Technol. 98:3526 3534. Gross, C.M., J.S. Angle, and M.S. Welterlen. 1990. Nutrient and sediment losses from turfgrass. J. Env iron. Qual. 19:663 668. Hamilton, G.W., and D.V. Waddington. 1999. Infiltration rates on residential lawns in central Pennsylvania. Journal of Soil and Water Conservation 54:564 568. Hamza, M.A., and W.K. Anderson. 2005. Soil compaction in cropping systems A review of the nature, causes and possible solutions. Soil Tillage Res. 82:121 145. Hanks, D., and A. Lewandowski. 2003. Protecting urban soil quality: Examples for landscape codes and specifications [Online]. Available by USDA NRCS http://soils.usda.gov/sqi/management/files/protect_urban_sq.pdf (verified April 7). Hawver, G.A., and N.L. Bassuk. 2007. Soils: The key to successful establishment of urban vegetation, In J. E. Kuser, ed. Urban and Community Forestry in the Northeast Springer, New York, NY. Heimlich, R.E., and K.S. Krupa. 1994. Changes in land quality accompanying urbanization in U.S fast growth counties. Journal of Soil and Water Conservation 49:367 373. Hipp, B ., S. Alexander, and T. Knowles. 1993. Use of resource efficient plants to reduce nitrogen, phosphorus, and pesticide runoff in residential and commercial landscapes. Water Sci. Technol. 28:205 213. Hirth, J.R., B.M. McKenzie, and J.M. Tisdall. 2005. Abili ty of seedling roots of Lolium perenne L. to penetrate soil from artificial biopores is modified by soil bulk density, biopore angle and biopore relief. Plant Soil 272:327 336. Jaber, F.H., S. Shukla, P.J. Stoffella, T.A. Obreza, and E.A. Hanlon. 2005. Imp act of organic amendments on groundwater nitrogen concentrations for sandy and calcareous soils. Compost Sci. Utilization 13:194 202. Jenerette, G.D., J. Wu, N.B. Grimm, and D. Hope. 2006. Points, patches, regions: Scaling soil biogeochemical patterns in a n urbanized arid ecosytem. Global Change Biol. 12:1532 1544. Jim, C.Y. 1993. Soil compaction as a constraint to tree growth in tropical & subtropical urban habitats. Environ. Conservation 20:35 49. Jim, C.Y. 1998. Urban soil characteristics and limitations for landscape planting in Hong Kong. Landscape Urban Planning 40:235 249.

PAGE 128

128 Johnson, G.A., J.G. Davis, Y.L. Qian, and K.C. Doesken. 2006. Topdressing turf with composted manure improves soil quality and protects water quality. Soil Sci. Soc. Am. J. 70:2114 2121. Kaye, J.P., P.M. Groffman, N.B. Grimm, L.A. Baker, and R.V. Pouyat. 2006. A distinct urban biogeochemistry? Trends Ecol. Evolution 21:192 199. Khaleel, R., K.R. Reddy, and M.R. Overcash. 1981. Changes in soil physical properties due to organic waste applications: A review. J. Environ. Qual. 10:133 141 Kidder, G., E.A. Hanlon, T.H. Yeager, and G.L. Miller. 1998. IFAS standardized fertilization recommendations for environmental horticulture crops University of Florida, IFAS, Gainesville, FL. King, K.W., R.D. Harmel, A. Torbert, and J.C. Balogh. 2001. Impact of a turfgrass system on nutrient loadings to surface water. J. Am. Water Resour. Assoc. 37:629 640. Knox, G.T., T. Broschat, and R. Black. 2002. Fertilizer recommendations for landscape plants [Onlin e]. Available by University of Florida IFAS http://edis.ifas.ufl.edu/EP114 (verified 21 October 2009). Kozlowski, T.T. 1999. Soil compaction and growth of woody plants. Scand. J. For. Res. 14:596 619. Landsch oot, P., and A. McNitt. 2004. Improving turf with compost. Biocycle 34:54 58. Law, N., L. Band, and M. Grove. 2004. Nitrogen input from residential lawn care practices in suburban watersheds in Baltimore county, MD. J. Envrion. Planning Management 47:737 755. Li, Q., J. Chen, R.D. Caldwell, and M. Deng. 2009. Cowpeat as a substitute for peat in container substrates for foliage plant propagation. HortTechnology 19:340 345. Lichter, J.M., and P.A. Lindsey. 1994. The use of surface treatments for the prevent ion of soil compaction during site construction. J. Arboriculture 20:205 209. Linde, D.T., and L.D. Hepner. 2005. Turfgrass seed and sod establishment on soil amended with biosolid compost. HortTechnology 15:577 583. Lipiec, J., and W. Stepniewski. 1995. E ffects of soil compaction and tillage systems on uptake and losses of nutrients. Soil & Tillage Research 35:37 52. Mallin, M.A., and T.L. Wheeler. 2000. Nutrient and fecal coliform discharge from costal North Carolina golf courses. J. Environ. Qual. 29:979 986. Martens, D.A., and W.T. Frankenberger. 1992. Modification of infiltration rates in an organic amended irrigated soil. Agron. J. 84:707 717.

PAGE 129

129 Meek, B.D., E.R. Rechel, L.M. Carter, W.R. Detar, and A.L. Urie. 1992. Infiltration rate of a sandy loam soil Effects of traffic, tillage, and plant roots. Soil Sci. Soc. Am. J. 56:908 913. Montagu, K.D., J.P. Conroy, and B.J. Atwell. 2001. The position of localized soil compaction determines root and subsequent shoot growth responses. J. Exp. Bot. 52:2127 2133. Montague, T., C. McKenney, M. Maurer, and B. Winn. 2007. Influence of irrigation volume and mulch on establishment of select shrub species. Arboriculture Urban For. 33:202 209. Mulholland, B., A. Hussain, C. Black, I. Taylor, and J. Roberts. 1999. Does ro ot sourced ABA have a role in mediating growth and stomatal responses to soil compaction in tomato ( Lycopersicon esculentum ) Physiol. Plant. 107:267 276. Mylavarapu, R.S., and E.D. Kennelley. 2002. UF/IFAS Extension soil testing laboratory (ESTL) analytica l procedures and training manual. Circular 1248. University of Florida, Gainesville, FL. Pandey, C., and S. Shukla. 2006. Effects of soil organic amendment on water and nutrient movement in a sandy soil. 2006 ASABE Annual International Meeting, Portland, O R. Pickett, S.T.A., M.L. Cadenasso, J.M. Grove, P.M. Groffman, L.E. Band, C.G. Boone, W.R. Burch, C.S.B. Grimmond, J. Hom, J.C. Jenkins, N.L. Law, C.H. Nilon, R.V. Pouyat, K. Szlavecz, P.S. Warren, and M.A. Wilson. 2008. Beyond urban legends: An emerging f ramework of urban ecology, as illustrated by the Baltimore Ecosystem Study. Bioscience 58:139 150. Pittenger, D.R., D.A. Shaw, D.R. Hodel, and D.B. Holt. 2001. Responses of landscape groundcovers to minimum irrigation. J. Environ. Hortic. 19:78 84. Pouyat, R.V., I.D. Yesilonis, and D.J. Nowak. 2006. Carbon storage by urban soils in the United States. J. Environ. Qual. 35:1566 1575. Pouyat, R.V., I.D. Yesilonis, J. Russell Anelli, and N.K. Neerchal. 2007. Soil chemical and physical properties that differenti ate urban land use and cover types. Soil Sci Soc Am J 71:1010 1019. Randrup, T.B. 1997. Soil compaction on construction sites. J. Arboriculture 23:207 210. Randrup, T.B., and K. Dralle. 1997. Influence of planning and design on soil compaction in construct ion sites. Landscape Urban Planning 38:87 92. Reed, S., D. Shinde, K. Konomi, K. Jayachandran, P. Nkedi Kizza, and M.R. Savabi. 2006. Phosphorus leaching potential from compost amendments in a carbonatic soil. Soil Sci. 171:865 873.

PAGE 130

130 Rivenshield, A. 2003. T he effects of organic amendments on tree growth in compacted soils. Ph.D Dissertation, Cornell University, Ithaca, NY. Rivenshield, A., and N. Bassuk. 2007. Using organic amendments to decrease bulk density and increase macroporosity. Arboriculture Urban F or. 33:140 146. Saha, S.K., L.E. Trenholm, and J.B. Unruh. 2005. Effect of fertilizer source on water use of St. Augustinegrass and ornamental plants. HortScience 40:2164 2166. Sartain, J.B. 2007. General recommendations for fertilization of turfgrasses on Florida soils [Online]. Available by University of Florida IFAS http://edis.ifas.ufl.edu/LH014 (verified 21 October 2009). SAS Institute. 2003. SAS/STAT 9 and 9.1 users guide SAS Institute, Cary, NC. Schar enbroch, B.C., J.E. Lloyd, and J.L. Johnson Maynard. 2005. Distinguishing urban soils with physical, chemical, and biological properties. Pedobiologia 49:283 296. Scheiber, S.M., E.F. Gilman, M. Paz, and K.A. Moore. 2007. Irrigation affects landscape estab lishment of Burford Holy, Pittosporum, and Sweet Viburnum. HortScience 42:344 348. Shestak, C.J., and M.D. Busse. 2005. Compaction alters physical but not biological indices of soil health. Soil Sci Soc Am J 69:236 246. Shuman, L.M. 2003. Fertilizer source effects on phosphate and nitrate leaching through simulated golf greens. Environ. Pollut. 125:413 421. Shuman, L.M. 2004. Runoff of nitrate nitrogen and phosphorus from turfgrass after watering in. Commun. Soil Sci. Plant Anal. 35:9 24. Sims, J.T., R.R. S imard, and B.C. Joern. 1998. Phosphorus loss in agricultural drainage: Historical perspective and current research. J. Environ. Qual. 27:277 293. Smiley, E.T., L. Calfee, B.R. Fraedrich, and E.J. Smiley. 2006. Comparison of structural and noncompacted soil s for trees surrounded by pavement. Arboriculture Urban For. 32:164 169. Smith, K.D., P.B. May, and G.M. Moore. 2001. The influence of compaction and soil strength on the establishment of four Australian landscape trees. Journal of Aboriculture 27:1 7. Smi th, L., and K. Lawrence. 1985. Surface and injection fertilization of murraya paniculate, Boynton Beach, FL.

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131 South Florida Water Management District. 2008. Watering restrictions [Online]. Available by South Florida Water Management District my.swfwmd.gov/w atershortage (verified 22 December). St. Johns River Water Management District. 2008. Drought information and irrigation rule [Online]. Available by St. Johns River Water Management District http://sjr.state.fl.us/irrigationrule/index.html (verified 22 December). Staats, D., and J.E. Klett. 1995. Water conservation potential and quality of non turf groundcovers versus Kentucky bluegrass under increasing levels of drought stress. J. Environ. H ortic. 13:181 185. Stamatiadis, S., M. Werner, and M. Buchanan. 1999. Field assessment of soil quality as affected by compost and fertilizer application in a broccoli field (San Benito County, California). Appl. Soil Ecol. 12:217 225. Stirzaker, R.J., J.B. Passioura, and Y. Wilms. 1996. Soil structure and plant growth: Impact of bulk density and biopores. Plant Soil 185:151 162. Tan, K.H. 1996. Measurement of field capacity water, p. 67 68 Soil sampling, preparation, and analysis. Marcel Dekker, New York. T homas, G.W., G.R. Haszler, and R.L. Blevins. 1996. The effects of organic matter and tillage on maximum compactability of soils using the proctor test. Soil Sci. 161:502 508. Toth, J.D., Z.X. Dou, J.D. Ferguson, D.T. Galligan, and C.F. Ramberg. 2006. Nitro gen vs. phosphorus based dairy manure applications to field crops: Nitrate and phosphorus leaching and soil phosphorus accumulation. J. Environ. Qual. 35:2302 2312. U.S. Census Bureau. 2004. Population estimates [Online] http://www.census.gov/popest/estimates.php (verified 17 March 2008). UF IFAS. 2006. A guide to Florida Friendly landscaping: Florida yards and neighborhoods handbook, Gainesville, FL. Unger, P.W., and T.C. Kaspar. 1994. Soil compa ction and root growth A review. Agron. J. 86:759 766. Urban, J. 2008. Up By Roots. International Society of Arboriculture, Champaign, IL. US Composting Council. 2002. Test Methods for the Examination of Composting and Compost. USDA NRCS. 2004. Official soil series descriptions [Online]. Available by USDA NRCS http://soils.usda.gov/soils/technical/classification/osd/index.html (posted 10 February 2004; verified 21 October 2009).

PAGE 132

132 USEPA. 1983. Nitrogen, Ammonia Method 350.1 (Colorimetric, Automated, Phenate), Cincinnati, Ohio USEPA. 1986. Tests for evaluating solid waste. EPA Publication SW 846, Springfield, VA. USEPA. 2000. National water quality i nventory: 1998 report to congress ( http://www.epa.gov/305b/98report) Vogeler, I., R. Horn, H. Wetzel, and J. Krummelbein. 2005. Tillage effects on soil strength and solute transport. Soil Tillage Res. 88: 193 204 Warman, P.R., J.C. Burnham, and L.J. Eaton. 2009. Effects of repeated applications of municipal solid waste compost and fertilizers to three lowbush blueberry fields. Sci. Hortic. 122:393 398. Watson, G.W., and P. Kelsey. 2005. The impact of soil c ompaction on soil aeration and fine root density of Q uercus palustris Urban For. Urban Greening 4:69 74. Weindorf, D.C., R.E. Zartman, and B.L. Allen. 2006. Effect of compost on soil properties in Dallas, Texas. Compost Sci. Utilization 14:59 67. Whalley, W.R., E. Dumitru, and A.R. Dexter. 1995. Biological effects of soil compaction. Soil Tillage Res. 35:53 68. Wickham, J.D., R.V. O'Neill, K.H. Riitters, E.R. Smith, T.G. Wade, and K.B. Jones. 2002. Geographic targeting of increases in nutrient export due t o future urbanization. Ecol. Applic. 12:93 106. Wright, A.L., T.L. Provin, F.M. Hons, D.A. Zuberer, and R.H. White. 2007a. Compost source and rate effects on soil macronutrient availability under Saint Augustine grass and Bermuda grass turf. Compost Sci. U tilization 15:22 28. Wright, A.L., T.L. Provin, F.M. Hons, D.A. Zuberer, and R.H. White. 2007b. Soil micronutrient availability after compost addition to St. Augustine grass. Compost Sci. Utilization 15:127 134. Yavari, S., S. Eshghi, E. Tafazoli, and N. K arimian. 2009. Mineral elements uptake and growth of strawberry as influenced by organic substrates. J. Plant Nutr. 32:1498 1512. Zazueta, F.S., A. Brockway, L. Landrum, and B. McCarty. 2005. Turf irrigation for the home [Online]. Available by UF IFAS http://edis.ifas.ufl.edu/AE144 (verified 31 July 2009). Zhang, H. 1994. Organic matter incorporation affects mechanical properties of soil aggregates. Soil Tillage Res. 31:263 275.

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133 Zhang, S., H. Grip, and L. Lovd ahl. 2005. Effect of soil compaction on hydraulic properties of two loess soils in China. Soil & Tillage Research 90:117 125.

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134 BIOGRAPHICAL SKETCH Shawna Loper started her education at Silo Public School in the southeast part of Oklahoma. Growing up in rural Oklahoma, she first got her love of the outdoors and decided to pursue a field that would allow her to express that. From high school, she then decided the best choice for higher education was Oklahoma State University. At OSU she majored in Plan t and Soil Sciences, with an emphasis in agronomy. While attending OSU, she worked for a soil science professor. Her job duties included assisting with the collection and analysis of swine effluent application in a no till, semi arid, corn and soybean ro tational cropping system. She also assisted graduate students in the department with their collection of crop and soil samples during her time there. During her undergraduate studies, she was highly involved in the Agronomy Club lege of Agricultural Sciences and Natural Resources as an Agricultural Ambassador for three years. From OSU she decided to further pursue her interest in soil science and attend the University of Florida and focus on soil and water sciences. Florida of fered a unique opportunity that allowed her to explore urban soil/environmental issues. Having a felt the need to explore a different area and felt this would broaden her studies and skills. Sh e environmental job field.