Florida Vegetable Handbook 2011

Citrus & VegetableM A G A Z I N E

Production Handbook for Florida

2011-2012

VegetableStephen M. Olson, Ph.D.

University of Florida's North FloridaResearch and Education Center, Quincy

Bielinski Santos, Ph.D. University of Florida's Gulf Coast

Research and Education Center, Wimauma

Editors:

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AUTHORS

Daniel A. Botts, Director, Environmental and Pest Management Division, Florida Fruit & Vegetable Association - MaitlandC.K. Chandler, Professor, Gulf Coast Research and Education Center WimaumaMichael D. Dukes, Associate Professor, Agricultural and Biological Engineering Department - GainesvilleMary L. Lamberts, Extension Agent IV, District V - Miami-Dade County - HomesteadAndrew W. MacRae, Assistant Professor, Gulf Coast Research and Education Center - WimaumaEugene McAvoy, Extension Agent IV, Hendry County, LabelleJoseph W. Noling, Professor, Citrus Research and Education Center - Lake AlfredStephen M. Olson, Professor, North Florida Research and Education Center - QuincyMonica Ozores-Hampton, Assistant Professor, Southwest Florida Research and Education Center ImmokaleeNatalia Peres, Associate Professor, Gulf Coast Research and Education Center - WimaumaJames F. Price, Associate Professor, Gulf Coast Research and Education Center - WimaumaRichard N. Raid, Professor, Everglades Research and Education Center - Belle GladePam D. Roberts, Professor, Southwest Florida Research and Education Center - ImmokaleeBielinski M. Santos, Assistant Professor, Gulf Coast Research and Education Center - WimaumaEric H. Simonne, Professor, Office of District Directors - GainesvilleScott A. Smith, Coordinator, Economic Analysis, Food and Resource Economics Department - GainesvilleCrystal A. Snodgrass, Extension Agent I, Manatee County - PalmettoWilliam M. Stall, Professor Emeritus, Horticultural Sciences Department - GainesvilleDavid D. Sui, Extension Agent II, Palm Beach County - West Palm BeachGary E. Vallad, Assistant Professsor, Gulf Coast Research and Education Center - WimaumaSusan E. Webb, Associate Professor, Entomology and Nematology Department - GainesvilleAlicia J. Whidden, Extension Agent II, Hillsborough County, SeffnerVance M. Whitaker, Assistant Professor, Gulf Coast Research and Education Center WimaumaShouan Zhang, Assistant Professor, Tropical Research adn Education Center - HomesteadLincoln Zotarelli, Assistant Professor, Horticultural Sciences Department - Gainesville

PHOTOGRAPHSCover photos courtesy of Hank Dankers, Senior Biological Scientist, University of Florida/IFAS, NFREC - Quincy

Top line: foliar and fruit symptoms of Target spot Center: fruit and foliar symptoms of Tomato spotted wilt Bottom: foliar and fruit symptoms of Bacterial spot.

ACKNOWLEDGEMENTThe purpose of this book is to provide the best and most up-to-date information available to the primary users of this

book - the Florida vegetable industry. This is possible because of the efforts of many University of Florida faculty in several locations around the State. The editors gratefully acknowledge their contributions. The editors also wish to acknowledge the contributions of the following faculty who have retired or are no longer involved in extension:

Richard P. Cromwell Chad Hutchinson Kenneth D. Shuler Kenneth PerneznyKent E. Cushman Freddie Johnson Donald N. Maynard Allen G. SmajstrlaGeorge Hochmuth Thomas A. Kucharek O.N. Nesheim Charles Vavrina

Chapter

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Chapter 1. IntroductionS.M. Olson .......................................................................................... 1

Chapter 2. Soil and Fertilizer Management for Vegetable Production in FloridaE.H. Simonne and G.J. Hochmuth .................................................... 3

Chapter 3. Principles and Practices for Irrigation ManagementE.H. Simonne, M.D. Dukes and L. Zotarelli ................................... 17

Chapter 4. Nematodes and Their ManagementJ.W. Noling ....................................................................................... 29

Chapter 5. Weed ManagementW.M. Stall and A.W. MacRae........................................................... 39

Chapter 6. Alternative to Methyl Bromide Soil Fumigation for Florida Vegetable ProductionJ.W. Noling, D.A. Botts and A. W. MacRae .................................... 47

Chapter 7. Cole Crop Production in FloridaS.M. Olson, E.H. Simonne, W.M. Stall, G.E. Vallad, S.E. Webb andS.A. Smith ....................................................................................... 55

Chapter 8. Specialty Asian Vegetable Production in South FloridaM.L. Lamberts, E.J. McAvoy, D.D. Sui, A.J. Whidden and C.A. Snodgrass ................................................................................. 79

Chapter 9. Cucurbit Production in FloridaS.M. Olson, E.H. Simonne, W.M. Stall, P.D. Roberts, S.E. Webb and S.A. Smith ......................................................................................... 85

Chapter 10. Eggplant Production in FloridaB.M. Santos, W.M. Stall, S. Zhang, S.E. Webb, S.A. Smith, E.J. McAvoy and M. Ozores-Hampton ...................... 109

Chapter 11. Legume Production in Florida: Snapbean, Lima Bean,Southern pea, SnowpeaS.M. Olson, E.H. Simonne, W.M. Stall, S.E. Webb, S. Zhang, S.A. Smith, E.J. McAvoy and M. Ozores-Hampton ...................... 125

Chapter 12. Lettuce, Endive, Escarole Production in FloridaB.M. Santos, W.M. Stall, R.N. Raid and S.E. Webb ...................... 141

Chapter 13. Okra Production in FloridaB.M. Santos, W.M. Stall, S.M. Olson, S.E. Webb and S. Zhang ... 159

Chapter 14. Onion, Leek, and Chive Production in FloridaS.M. Olson, W.M. Stall, N.A. Peres and S.E. Webb ...................... 167

Chapter 15. Minor Vegetable Crops: Beets, Carrots, Celery and ParsleyM. Ozores-Hampton, W.M. Stall, S.E. Webb, R.N. Raid and S.M. Olson ...................................................................................... 181

Chapter 16. Pepper Production in FloridaS.M. Olson, E.H. Simonne, W.M. Stall, G.E. Vallad, S.E. Webb, E.J. McAvoy, S.A. Smith, M. Ozores-Hampton and B.M Santos ..................................................................................... 215

Chapter 17. Potato Production in FloridaL. Zotarelli, P.D. Roberts, W.M. Stall, S.E. Webb, S.A. Smith, B.M. Santos, S.M. Olson and E.H. Simonne ................................. 235

Chapter 18. Radish Production in FloridaM. Ozores-Hampton, W.M. Stall, R.N. Raid, S.E. Webb and E.J. McAvoy ....................................................................................253

Chapter 19. Spinach Production in FloridaS.M. Olson, W.M. Stall, S.E. Webb and R.N. Raid .......................261

Chapter 20. Strawberry Production in FloridaB.M. Santos, N.A. Peres, J.F. Price, C.K. Chandler, V.M. Whitaker, W.M. Stall, S.M. Olson, S.A. Smith and E.H. Simonne ................271

Chapter 21. Sweet Corn Production in FloridaM. Ozores-Hampton, W.M. Stall, S.M. Olson, S.E. Webb, S.A. Smith, R.N. Raid and E.J. McAvoy ........................................ 283

Chapter 22. Sweetpotato Production in FloridaS.M. Olson, M.L. Lamberts, W.M. Stall, S. Zhang and S.E. Webb ................................................................. 297

Chapter 23. Tomato Production in FloridaS.M. Olson, W.M. Stall, G.E. Vallad, S.E. Webb, S.A. Smith, E.H. Simonne, E.J. McAvoy, B.M Santos and M. Ozores-Hampton ....................................................................... 309

Chapter 24. Tropical Root Crop Production in FloridaM. L. Lamberts and S.M. Olson .................................................... 333

CONTENTS

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ADDITIONAL REFERENCES

More Information from the UF/IFAS Electronic Database Information System (EDIS, http://edis.ufas.ufl.edu):

1. on-line chapters of previous editions of the Vegetable Production Handbook

Variety Selection:http://edis.ifas.ufl.edu/document_cv102

Seed Quality and Seeding Technology:http://edis.ifas.ufl.edu/document_cv103

Transplant Production:http://edis.ifas.ufl.edu/document_cv104

Mulching:http://edis.ifas.ufl.edu/document_cv105

Row Covers for Growth Enhancement:http://edis.ifas.ufl.edu/document_cv106

Pesticide Safety:http://edis.ifas.ufl.edu/document_cv108

Interpreting PPE Statements on Pesticide Labels:http://edis.ifas.ufl.edu/document_cv285

The Worker Protection Standard:http://edis.ifas.ufl.edu/document_cv138

Calibration of Chemical Applicators Used in Vegetable Production:http://edis.ifas.ufl.edu/document_cv110

Insects that Affect Vegetable Crops:http://edis.ifas.ufl.edu/document_cv111

Integrated Disease Management for Vegetable Crops in Florida: http://edis.ifas.ufl.edu/document_cv291

Yields of Vegetables: http://edis.ifas.ufl.edu/document_cv114

Handling, Cooling and Sanitation Techniques for Maintaining Postharvest Quality:http://edis.ifas.ufl.edu/document_cv115

Marketing Strategies for Vegetable Growers:http://edis.ifas.ufl.edu/document_cv116

Production Costs for Selected Florida Vegetables:http://edis.ifas.ufl.edu/document_cv117

Pesticide Provisions of the Florida Agricultural Worker Safety Act (FAWSA):http://edis.ifas.ufl.edu/document_cv289

Principles and Practices of Food Safety for Vegetable Production in Florida:http://edis.ifas.ufl.edu/document_cv288

Introduction to Organic Crop Production:http://edis.ifas.ufl.edu/document_cv118

2. Additional References:

Automatic irrigation based on soil mois-ture for vegetable crops:http://edis.ifas.ufl.edu/AE354

Causes and prevention of emitter plugging in microirrigation systems:http://edis.ifas.ufl.edu/AE032

Drip-irrigation Systems for Small Conventional Vegetable Farms and Organic Vegetable Farms:http://edis.ifas.ufl.edu/HS388

Field devices for monitoring soil water content:http://edis.ifas.ufl.edu/AE266

Good worker health and hygiene practices: Training manual for produce handlers:http://edis.ifas.ufl.edu/FY743

Guidelines for enrolling in Floridas BMP program for vegetable crops:http://edis.ifas.ufl.edu/HS367

Injection of chemicals into irrigation systems: Rates, volumes and injection periods:http://edis.ifas.ufl.edu/AE116

Principles of micro irrigation:http://edis.ifas.ufl.edu/WI007

Treating irrigation systems with chlorine:http://edis.ifas.ufl.edu/AE080

Water quality/quantity best management practices for Florida vegetable and agro-nomic crops: http://www.floridaagwaterpolicy.com/PDF/Bmps/Bmp_VeggieAgroCrops2005.pdf

Water wells for Florida irrigation systems:http://edis.ifas.ufl.edu/WI002

Weather and Climate Tools for Agricultural Producers:http://edis.ifas.ufl.edu/AE440

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Call 911 for pesticide emergencies or the appropriate contact below:

* National Pesticide Information Center (NPIC), 800-858-7378, 9:30 a.m. through 6:30 p.m., 7 days a week.* The Poison Center Emergency Telephone Service, 800-222-1222* The manufacturer of the pesticide in question. Their phone number is listed on the pesticide label.

The information above was provided by the University of Floridas Institute of Food and Agricultural Sciences Pesticide Information Office 352-392-4721.

Crop Pages

Asian vegetables 79-84

Bean 125-140

Beet 181-214

Broccoli 55-77

Cabbage 55-77

Cantaloupe 85-107

Carrot 181-214

Cauliflower 55-77

Celery 181-214

Crop Pages

Tropical root crops 333-338

Chive 167-179

Collards 55-77

Cucumber 85-107

Eggplant 109-123

Endive, Escarole 141-158

Kale 55-77

Leek 167-179

Lettuce 141-158

Crop Pages

Lima bean 125-140

Mustard 55-77

Okra 159-166

Onion 167-179

Parsley 181-214

Pepper 215-234

Potato 235-251

Radish 253-259

Snowpea 125-140

Crop Pages

Southernpea 125-140

Spinach 261-270

Squash 85-107

Strawberry 271-282

Sweet corn 283-296

Sweetpotato 297-308

Tomato 309-332

Turnip 55-77

Watermelon 85-107

CROP INDEX

FLORIDA COUNTY COOPERATIVE EXTENSION OFFICES

FLORIDA PESTICIDE EMERGENCY PHONE LIST

ALACHUA COUNTY EXTENSION OFFICE2800 NE 39th AvenueGainesville, Florida 32609-2658PH: (352) 955-2402FAX: (352) 334-0122E-MAIL: [email protected]://alachua.ifas.ufl.edu

BAKER COUNTY EXTENSION OFFICE1025 West Macclenny Ave.Macclenny, Florida 32063-9640PH: (904) 259-3520FAX: (904) 259-9034E-MAIL: [email protected]://baker.ifas.ufl.edu

BAY COUNTY EXTENSION OFFICE2728 E. 14th StreetPanama City, Florida 32401-5022PH: (850) 784-6105FAX: (850) 784-6107EMAIL: [email protected]://bay.ifas.ufl.edu

BRADFORD COUNTY EXTENSION OFFFICE2266 North Temple AvenueStarke, Florida 32091-1612PH: (904) 966-6224FAX: (904) 964-9283EMAIL: [email protected]://bradford.ifas.ufl.edu

BREVARD COUNTY EXTENSION OFFICE3695 Lake DriveCocoa, Florida 32926-4219PH: (321) 633-1702FAX: (321) 633-1890EMAIL: [email protected]://brevard.ifas.ufl.edu

BROWARD COUNTY EXTENSION OFFICE3245 College AvenueDavie, Florida 33314-7719PH: (954) 357-5270FAX: (954) 357-5271EMAIL: [email protected] www.broward.org/extension

CALHOUN COUNTY EXTENSION OFFICE20816 Central Ave. East Suite1Blountstown, Florida 32424-2292PH: (850) 674-8323FAX: (850) 674-8353EMAIL: [email protected]://calhoun.ifas.ufl.edu

CHARLOTTE COUNTY EXTENSION OFFICE25550 Harbor View Road, Suite 3Port Charlotte, Florida 33980-2503PH: (941) 764-4340FAX: (941) 764-4343EMAIL: [email protected]://charlotte.ifas.ufl.edu

CITRUS COUNTY EXTENSION OFFICE3650 West Sovereign Path, Suite 1 Lecanto, FL 34461-8070 PH: (352) 527-5700FAX: (352) 527-5749EMAIL: [email protected]://citrus.ifas.ufl.edu

CLAY COUNTY EXTENSION OFFICE2463 SR 16WP.O. Box 278Green Cove Springs, Florida 32043-0278PH: (904) 284-6355FAX: (904) 529-9776EMAIL: [email protected]://clay.ifas.ufl.edu

COLLIER COUNTY EXTENSION OFFICE14700 Immokalee RoadNaples, Florida 34120-1468PH: (239) 353-4244FAX: (239) 353-7127EMAIL: [email protected]://collier.ifas.ufl.edu

COLUMBIA COUNTY EXTENSION OFFICE164 SW Mary Ethel Ln,Lake City, Florida 32025-1597PH: (386) 752-5384FAX: (386) 758-2173EMAIL: [email protected]://columbia.ifas.ufl.edu

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DESOSTO COUNTY EXTENSION OFFICE2150 Northeast Roan StreetArcadia, Florida 34266-5025PH: (863) 993-4846FAX: (863) 993-4849EMAIL: [email protected]://desoto.ifas.ufl.edu

DIXIE COUNTY EXTENSION OFFICE99 Northeast 121st Street P.O. Box 640Cross City, Florida 32628-0640PH: (352) 498-1237FAX: (352) 498-1471EMAIL: [email protected]://dixie.ifas.ufl.edu

DUVAL COUNTY EXTENSION OFFICE1010 North McDuff Ave.Jacksonville, Florida 32254-2083PH: (904) 387-8850FAX: (904) 387-8902EMAIL: [email protected]://duval.ifas.ufl.edu

ESCAMBIA COUNTY EXTENSION OFFICE3740 Stefani RoadCantonment, Florida 32533-7792PH: (850) 475-5230FAX: (850) 475-5233EMAIL: [email protected]://escambia.ifas.ufl.edu

FLAGLER COUNTY EXTENSION OFFICE150 Sawgrass RoadBunnell, Florida 32110-4325PH: (386) 437-7464FAX: (386) 586-2102EMAIL: [email protected] http://www.flaglercounty.org

FRANKLIN COUNTY EXTENSION OFFICE66 Fourth StreetApalachicola, Florida 32320-1775PH: (850) 653-9337FAX: (850) 653-9447EMAIL: [email protected]://franklin.ifas.ufl.edu

GADSDEN COUNTY EXTENSION OFFICE2140 West Jefferson Street Quincy, Florida 32351-1905PH: (850) 875-7255FAX: (850) 875-7257EMAIL: [email protected]://gadsden.ifas.ufl.edu

GILCHRIST COUNTY EXTENSION OFFICE125 East Wade Street P.O. Box 157Trenton, Florida 32693-0157PH: (352) 463-3174FAX: (352) 463-3197EMAIL: [email protected]://gilchrist.ifas.ufl.edu

GLADES COUNTY EXTENSION OFFICE900 US 27, SW P.O. Box 549Moore Haven, Florida 33471-0549PH: (863) 946-0244FAX: (863) 946-0629EMAIL: [email protected]://glades.ifas.ufl.edu

GULF COUNTY EXTENSION OFFICE200 N 2nd StreetP.O. Box 250Wewahitchka, Florida 32465-0250PH: (850) 639-3200FAX: (850) 639-3201EMAIL: [email protected]://gulf.ifas.ufl.edu

HAMILTON COUNTY EXTENSION OFFICE1143 NW US Highway 41 Jasper, Florida 32052-5856PH: (386) 792-1276FAX: (386)792-6446EMAIL: [email protected]://hamilton.ifas.ufl.edu

HARDEE COUNTY EXTENSION OFFICE507 Civic Center Drive Wauchula, Florida 33873-9460PH: (863) 773-2164FAX: (863) 773-6861EMAIL: [email protected]://hardee.ifas.ufl.edu

HENDRY COUNTY EXTENSION OFFICE1085 Pratt Blvd P.O. Box 68 LaBelle, Florida 33975-0068PH: (863) 674-4092FAX: (863) 674-4637EMAIL: [email protected]://hendry.ifas.ufl.edu

HERNANDO COUNTY EXTENSION OFFICE1653 Blaise DriveBrooksville, Florida 34601PH: (352) 754-4433FAX: (352) 754-4489EMAIL: [email protected] http://www.co.hernando.fl.us/county_exten-sion/

HIGHLANDS COUNTY EXTENSION OFFICE4509 George Blvd. Sebring, Florida 33875-5837PH: (863) 402-6540FAX: (863) 402-6544EMAIL: [email protected]://highlands.ifas.ufl.edu

HILLSBOROUGH COUNTY EXTENSION OFFICE5339 County Road 579 Seffner, Florida 33584-3334PH: (813) 744-5519FAX: (813) 744-5776EMAIL: [email protected]://hillsborough.ifas.ufl.edu

HOLMES COUNTY EXTENSION OFFICE1169 East Hwy 90 Bonifay, Florida 32425-6012PH: (850) 547-1108FAX: (850) 547-7433EMAIL: [email protected]://holmes.ifas.ufl.edu

INDIAN RIVER EXTENSION OFFICE1028 20th Place, Suite DVero Beach, Florida 32960-5305PH: (772) 770-5030FAX: (772) 770-5148EMAIL: [email protected]://indian.ifas.ufl.edu

JACKSON COUNTY EXTENSION OFFICE2741 Pennsylvania Avenue, Suite 3Marianna, Florida 32448-4022PH: (850) 482-9620FAX: (850) 482-9287EMAIL: [email protected]://jackson.ifas.ufl.edu

JEFFERSON COUNTY EXTENSION OFFICE275 North Mulberry StreetMonticello, Florida 32344-1423PH: (850) 342-0187FAX: (850) 997-5260EMAIL: [email protected]://jefferson.ifas.ufl.edu

LAFAYETTE COUNTY EXTENSION OFFICE176 Southwest Community Circle, Suite DMayo, Florida 32066-4000PH: (386) 294-1279FAX: (386) 294-2016EMAIL: [email protected]://lafayette.ifas.ufl.edu

Chapter

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LAKE COUNTY EXTENSION OFFICE1951 Woodlea Road Tavares, Florida 32778-4407PH: (352) 343-4101FAX: (352) 343-2767EMAIL: [email protected] http://lake.ifas.ufl.edu LEE COUNTY EXTENSION OFFICE3406 Palm Beach Blvd.Fort Myers, Florida 33916-3736PH: (239) 533-4327FAX: (239) 485-2305EMAIL: [email protected] http://lee.ifas.ufl.edu

LEON COUNTY EXTENSION OFFICE615 Paul Russell RoadTallahassee, Florida 32301-7099PH: (850) 606-5200FAX: (850) 606-5201EMAIL: [email protected] http://leon.ifas.ufl.edu

LEVY COUNTY EXTENSION OFFICE625 North Hathaway Avenue, Alt 27 P.O. Box 219Bronson, Florida 32621-0219PH: (352) 486-5131FAX: (352) 486-5481EMAIL: [email protected]://levy.ifas.ufl.edu

LIBERTY COUNTY EXTENSION OFFICE10405 Northwest Theo Jacobs Way Bristol, Florida 32321-3299PH: (850) 643-2229FAX: (850) 643-3584EMAIL: [email protected]://liberty.ifas.ufl.edu

MADISON COUNTY EXTENSION OFFICE184 NW College LoopMadison, Florida 32340-1412PH: (850) 973-4138FAX: (850) 973-2000EMAIL: [email protected]://madison.ifas.ufl.edu

MANATEE COUNTY EXTENSION OFFICE1303 17th Street WestPalmetto, Florida 34221-2934PH: (941) 722-4524FAX: (941) 721-6608EMAIL: [email protected]://manatee.ifas.ufl.edu

MARION COUNTY EXTENSION OFFICE2232 NE Jacksonville Rd.Ocala, Florida 34470-3615PH: (352) 671-8400FAX: (352) 671-8420EMAIL: [email protected]:// marion.ifas.ufl.edu

MARTIN COUNTY EXTENSION OFFICE2614 S.E. Dixie Hwy.Stuart, Florida 34996-4007 PH: (772) 288-5654FAX: (772) 288-4354EMAIL: [email protected]://martin.ifas.ufl.edu

MIAMI-DADE COUNTY EXTENSION OFFICE18710 SW 288th StreetHomestead, Florida 33030-2309PH: (305) 248-3311FAX: (305) 246-2932EMAIL: [email protected]://miami-dade.ifas.ufl.edu/

MONROE COUNTY EXTENSION OFFICE1100 Simonton Street, # 2-260Key West, Florida 33040-3110PH: (305) 292-4501FAX: (305) 292-4415EMAIL: [email protected]://monroe.ifas.ufl.edu

NASSAU COUNTY EXTENSION OFFICE543350 US Hwy. 1Callahan, Florida 32011-6486PH: (904) 879-1019FAX: (904) 879-2097EMAIL: [email protected]://nassau.ifas.ufl.edu

OKALOOSA COUNTY EXTENSION OFFICE5479 Old Bethel RoadCrestview, Florida 32536-5512PH: (850) 689-5850 FAX: (850) 689-5727EMAIL: [email protected]://okaloosa.ifas.ufl.edu

OKEECHOBEE COUNTY EXTENSION OFFICE458 Hwy. 98 North Okeechobee, Florida 34972-2303PH: (863) 763-6469FAX: (863) 763-6745EMAIL: [email protected]://okeechobee.ifas.ufl.edu

ORANGE COUNTY EXTENSION OFFICE6021 South Conway RoadOrlando, Florida 32812-3604PH: (407) 254-9200FAX: (407) 850-5125EMAIL: [email protected]://orange.ifas.ufl.edu/

OSCEOLA COUNTY EXTENSION OFFICE1921 Kissimmee Valley LaneKissimmee, Florida 34744-6107PH: (321) 697-3000FAX: (321) 697-3010EMAIL: [email protected] http://osceola.ifas.ufl.edu

PALM BEACH COUNTY EXTENSION OFFICE559 North Military TrailWest Palm Beach, Florida 33415-1311PH: (561) 233-1700FAX: (561) 233-1768EMAIL: [email protected]://palm-beach.ifas.ufl.edu

PASCO COUNTY EXTENSION OFFICE36702 SR 52Dade City, Florida 33525-5198PH: (352) 521-4288FAX: (352) 523-1921EMAIL: [email protected]://pasco.ifas.ufl.edu

PINELLAS COUNTY EXTENSION OFFICE12520 Ulmerton Road Largo, Florida 33774-3602PH: (727) 582-2100FAX: (727) 582-2149EMAIL: [email protected] http://pinellas.ifas.ufl.edu

POLK COUNTY EXTENSION OFFICE1702 Highway 17-98 South Bartow, Florida 33830 P.O. Box 9005 Drawer HS03Bartow, FL 33831-9005PH: (863) 519-8677FAX: (863) 534-0001EMAIL: [email protected] http://polk.ifas.ufl.edu

PUTNAM COUNTY EXTENSION OFFICE111 Yelvington Road, Suite 1East Palatka, Florida 32131-2114PH: (386) 329-0318FAX: (386) 329-1262EMAIL: Putnam@ ifas.ufl.eduhttp://putnam.ifas.ufl.edu


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SANTA ROSA COUNTY EXTENSION OFFICE6263 Dogwood DriveMilton, Florida 32570-3500PH: (850) 623-3868FAX: (850) 623-6151EMAIL: [email protected] http://santarosa.ifas.ufl.edu

SARASOTA COUNTY EXTENSION OFFICE6700 Clark Road Sarasota, Florida 34241-9328PH: (941) 861-5000FAX: (941) 861-9886EMAIL: [email protected] http://sarasota.ifas.ufl.edu

SEMINOLE COUNTY EXTENSION OFFICE250 W. County Home Rd.Sanford, Florida 32773-6189PH: (407) 665-5551FAX: (407) 665-5563EMAIL: [email protected] http://www.seminolecountyfl.gov/coopext/

ST. JOHNS COUNTY EXTENSION OFFICE3125 Agricultural Center DriveSt. Augustine, Florida 32092-0572PH: (904) 209-0430FAX: (904) 209-0431EMAIL: [email protected]://stjohns.ifas.ufl.edu

ST. LUCIE COUNTY EXTENSION OFFICE8400 Picos Road, Suite 101Fort Pierce, Florida 34945-3045PH: (772) 462-1660FAX: (772) 462-1510EMAIL: Stlucie@ ifas.ufl.eduhttp://stlucie.ifas.ufl.edu

SUMTER COUNTY EXTENSION OFFICE7620 State Road 471, Suite 2 Bushnell, Florida 33513-8716PH: (352) 793-2728FAX: (352) 793-6376EMAIL: [email protected] http://sumter.ifas.ufl.edu

SUWANNEE COUNTY EXTENSION OFFICE1302 11th Street SWLive Oak, Florida 32064-3600PH: (386) 362-2771FAX: (386) 364-1698EMAIL: Suwannee@ ifas.ufl.eduhttp://suwannee.ifas.ufl.edu

TAYLOR COUNTY EXTENSION OFFICE203 Forest Park Drive Perry, Florida 32348-6340PH: (850) 838-3508FAX: (850) 838-3546EMAIL: [email protected]://taylor.ifas.ufl.edu

UNION COUNTY EXTENSION OFFICE25 NE 1st StreetLake Butler, Florida 32054-1701PH: (386) 496-2321FAX: (386) 496-1111EMAIL: [email protected]://union.ifas.ufl.edu

VOLUSIA COUNTY EXTENSION OFFICE3100 E New York Ave. Deland, Florida 32724-6497PH: (386) 822-5778FAX: (386) 822-5767EMAIL: Volusia@ ifas.ufl.eduhttp://volusia.org/extension

WAKULLA COUNTY EXTENSION OFFICE84 Cedar AvenueCrawfordville, Florida 32327-2063PH: (850) 926-3931FAX: (850) 926-8789EMAIL: [email protected]://wakulla.ifas.ufl.edu

WALTON COUNTY EXTENSION OFFICE732 North 9th Street DeFuniak Springs, Florida32433-3804PH: (850) 892-8172FAX: (850) 892-8443EMAIL: Walton@ ifas.ufl.eduhttp://walton.ifas.ufl.edu

WASHINGTON COUNTY EXTENSION OFFICE1424 Jackson Ave., Suite AChipley, Florida 32428-1602PH: (850) 638-6180FAX: (850) 638-6181EMAIL: Washington@ ifas.ufl.eduhttp://washington.ifas.ufl.edu

DISCLAIMER - We appreciate the financial support of Valent in the production of this publication. The use of trade names and advertisements in this

publication is solely for the purpose of providing specific information. It is not a guarantee or warranty of the products named, and does not signify that they are approved to the exclusion of others of suitable composition. Use pesticides safely. Read and follow directions on the manufacturers label.

IFAS INFO - The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,

educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handi-cap, or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office/ Florida Cooperative Service/ Institute of Food and Agricultural Sciences/ University of Florida/ Millie Ferrer-Chaney, Dean.

See our web sites with electronic extension publications at http://edis.ifas.ufl.edu and for more information visit "Solutions for your life" at http://solutionsforyourlife.ufl.edu

Chapter 1.IntroductionS.M. Olson

Florida ranks second among the states in fresh market vegetable production on the basis of harvested acreage (10.7 %), production (9.3 %) and value (13.3 %) of the crops grown (Table 1). In 2009, vegetables were harvested from 220,800 acres and had a farm value exceeding 1.8 billion dollars.

A more detailed analysis of the national importance of Florida production of specific vegetables indicates that Florida ranks first in fresh-market value of snap bean, cucumber, squash, sweet corn, tomatoes and watermelons. Florida ranks second in fresh market value of strawberry, sweet pepper and cabbage.

More than 40 different crops are grown commercially in Florida with 7 of these exceeding $100 million in value. Harvest occurs in late fall, winter and spring when at times the only available United States supply is from Florida.

On the basis of value, in 2009 tomato production accounted for about 28.5 % of the states total value. Other major crops with a lesser proportion of the 2009 crop value were strawberry (17.2 %), sweet corn (12.4 %), sweet pep-per (10.9 %), watermelon (7.4 %), potatoes (7.0 %), snap beans (6.2 %), cucumber (4.3 %), cabbage (3.3 %) and squash (2.8 %).

Table 1. Leading fresh market vegetable producing states, 2009.

Harvested acreage Production Value

Rank State Percent of total State Percent of total State Percent of total

1 California 43.9 California 49.4 California 52.1

2 Florida 10.7 Florida 9.3 Florida 13.3

3 Arizona 6.7 Arizona 7.1 Arizona 7.4

4 Georgia 6.4 Georgia 5.1 Georgia 5.1

5 New York 3.8 Washington 3.6 New York 2.7

Source: Vegetables, USDA Ag Statistics, 2010.

2011-2012

Chapter 2.

Soil and Fertilizer Management for Vegetable Production in FloridaE.H. Simonne and G.J. Hochmuth

BEST MANAGEMENT PRACTICESWith the passage of the Federal Clean Water Act

(FCWA) in 1972, states were required to assess the impacts of non-point sources of pollution on surface and ground waters, and establish programs to minimize them. Section 303(d) of the FWCA also requires states to iden-tify impaired water bodies and establish total maximum daily loads (TMDLs) for pollutants entering these water bodies. Water quality parameters targeted by the TMDLs and involving vegetable production are concentrations of nitrate, phosphate, and total dissolved solids in these waters. A TMDL establishes the maximum amount of pol-lutant a water body can receive and still keep its water quality parameters consistent with its intended use (swim-ming, fishing, or potable uses). The establishment of the TMDLs is currently underway and they will be implement-ed through a combination of regulatory, non-regulatory, and incentive-based measures. Best Management Practices (BMPs) are specific cultural practices aimed at reduc-ing the load of a specific compound, while maintaining or increasing economical yields. They are tools available to vegetable growers to achieve the TMDLs. BMPs are intended to be educational, economically sound, environ-mentally effective, and based on science. It is important to recognize that BMPs do not aim at becoming an obstacle to vegetable production. Instead, they should be viewed as a means to balance economical vegetable production with environmental responsibility.

The BMPs that will apply to vegetable production in Florida are described in the Agronomic and Vegetable Crop Water Quality/Water Quantity BMP Manual for Florida. This manual was developed between 2000 and 2005 through a cooperative effort between state agen-cies, water management districts and commodity groups, and under the scientific leadership of the University of Floridas Institute of Food and Agricultural Sciences (UF/IFAS). The manual has undergone a thorough scientific review in 2003 and was presented to stakeholders and state commodity groups for feed back in 2004. The manual was adopted by reference in 2006 and by rule in Florida Statutes (5M-8 Florida Administrative Code) and may be consulted on-line at http://www.floridaagwaterpolicy.com/PDFs/BMPs/vegetable&agronomicCrops.pdf. BMPs are 1-to-3 page long chapters that include a picture, a working definition of the topic, list specific things to do (BMPs) as

well as things to avoid (pitfalls), and present existing appli-cable technical criteria together with additional references.

Vegetable growers may get one-on-one information on 1) the benefits for joining the BMP program, 2) how to join it, 3) how to select the BMPs that apply to their opera-tion and 4) record keeping requirements by getting in con-tact with their county extension agent or their local imple-mentation team (see the vegetable BMP website at www. imok.ufl.edu/bmp/vegetable for more information).

The vegetable BMPs have adopted all current UF/IFAS recommendations, including those for fertilizer and irriga-tion management (see BMP no. 33 "Optimum Fertilizer Management" on pg. 93 of BMP manual). Through the implementation of a series of targeted cultural practices (the BMPs), growers should be able to reconcile economi-cal profitability and responsible use of water and fertilizer. At the field level, adequate fertilizer rates should be used together with irrigation scheduling techniques and crop nutritional status monitoring tools (leaf analysis, petiole sap testing). In the BMP manual, adequate fertilizer rates may be achieved by combinations of UF/IFAS recom-mended base rates and supplemental fertilizer applications.

SOILS

Vegetables are grown on more than 300,000 acres in vari-ous soil types throughout the state. These soil types include sandy soils, sandy loam soils, Histosols (organic muck), and calcareous marl soils. Each soil group is described below.

SandsSandy soils make up the dominant soil type for vegetable

production in Florida (Fig. 2-1). Vegetables are produced on sandy soils throughout the Florida peninsula and on sandy soils and sandy loams in the panhandle. Sandy soils have the advantage of ease of tillage and they can produce the earliest vegetable crops for a particular region. Sandy soils allow timely production operations such as planting and harvesting. Sandy soils, however, have the disadvantage that mobile nutrients such as nitrogen, potassium and even phosphorus can be leached by heavy rain or over irrigation. Therefore, sands must be managed carefully with regard to fertility programs. Sands hold very little water; therefore,

2011-2012

Vegetable Production HandbookPage 4

Table 1. Fertilizer nutrients required by plants.

Nutrient Deficiency symptoms Occurrence

Nitrogen (N) Stems thin, erect, hard. Leaves small, yellow; on some crops (tomatoes) undersides are reddish.Lower leaves affected first.

On sandy soils especially after heavy rain or after over-irrigation. Also on organic soils during coolgrowing seasons.

Phosphorus (P) Stems thin and shortened. Leaves develop purple color. Older leaves affected first. Plants stunted and maturity delayed.

On acidic soils or very basic soils. Also when soils are cool and wet.

Potassium (K) Older leaves develop gray or tan areas on leaf margins. Eventually a scorch appears on the entire margin.

On sandy soils following leaching rains or overirrigation.

Boron (B) Growing tips die and leaves are distorted. Specific diseases caused by boron deficiency include brown curd and hollow stem of cauliflower, cracked stem of celery, blackheart of beet, and internal browning of turnip.

On soils with pH above 6.8 or on sandy, leached soils, or on crops with very high demand such as cole crops.

Calcium (Ca) Growing-point growth restricted on shoots and roots. Specific deficiencies include blossom-end rot of tomato, pepper and watermelon, brownheart of escarole, celery blackheart, and cauliflower or cabbage tipburn.

On strongly acidic soils, or during severe droughts.

Copper (Cu) Yellowing of young leaves, stunting of plants. Onion bulbs are soft with thin, pale scales.

On organic soils or occasionally new mineral soils.

Iron (Fe) Distinct yellow or white areas between veins on youngest leaves.

On soils with pH above 6.8.

Magnesium (Mg) Initially older leaves show yellowing between veins, followed by yellowing of young leaves.

On strongly acidic soils, or on leached sandy soils.

Older leaves soon fall.

Manganese (Mn) Yellow mottled areas between veins on youngest leaves, not as intense as iron deficiency.

On soils with pH above 6.4.

Molybdenum (Mo) Pale, distorted, narrow leaves with some interveinal yellowing of older leaves, e.g. whiptail disease of cauliflower. Rare.

On very acidic soils.

Zinc (Zn) Small reddish spots on cotyledon leaves of beans; light areas (white bud) of corn leaves.

On wet, cold soils in early spring or where excessive phosphorus is present.

Sulfur (S) General yellowing of younger leaves and reduced growth. On very sandy soils, low in organic matter, especially following continued use of sulfur-free fertilizers and especially in areas that receive little atmospheric sulfur.

Chlorine (Cl) Deficiencies very rare. Usually only under laboratory conditions.

irrigation management is more critical compared to other soil types used for vegetable production in Florida. Nearly all vegetable crops produced in Florida can be successfully grown on sandy soils. The major vegetable crops such as tomatoes, peppers, potatoes, watermelons, strawberries, and cabbage are grown commonly on sandy soils.

HistosolsHistosols are organic soils which occur in areas through-

out the peninsula, especially in southern and central Florida (Fig. 2-2). Large organic deposits used for vegetable pro-duction occur south of Lake Okeechobee. Smaller pockets of muck occur throughout central and northern Florida. Histosols consist largely of decomposing plant material and are largely underlain by calcareous deposits. Muck soils have large water and nutrient holding capacities and are used to produce crops such as the leafy vegetables (leaf let-tuce, and various greens), celery, sweet corn, and radishes. With time, the organic matter decomposes and the muck

subsides. Thus, the pH in the muck can increase because of proximity to the underlying calcareous material. Muck subsidence causes problems for water and nutrient man-agement. The increase in pH due to subsidence and also to the practice of flooding the Histosols to reduce oxidation can result in increased requirements of phosphorus and micronutrients. These nutrients can be fixed by the high pH of the soil. Nutrient management in these situations should involve banding rather than increased rates of nutrients.

Calcareous Rock and MarlThe calcareous soils in southern Florida (Miami-

Dade County) consist of two phases, rockland and marl. Rockland soils are calcium carbonate soils consisting of particles that range from sand-like in size to pebble and gravel (Fig. 2-3). The rockland soils are extremely shallow, about 4 to 6 inches deep. The marl is the fine-textured, clay-like phase of the calcium carbonate soils. Tomatoes, beans, summer squash, okra, sweet corn, boni-

Chapter 2: Soil and Fertilizer Management for Vegetable Production in Florida Page 5

ato, and strawberries can be produced in the winter months on the rockland soils of Miami-Dade County. Potatoes, malanga, snap beans and sweet corn are produced on the marl. Both soils have extremely high pH, therefore, nutrients such as phosphorus and micronutrients must be banded to ensure availability.

SOIL TESTING

Plants require 16 elements for normal growth and repro-duction, 13 of which are presented in Table 1. The crop nutrient requirement (CNR) for a particular element is defined as the total amount in lb/A of that element needed by the crop to produce economic optimum yield. This con-cept of economic optimum yields is important for vegeta-bles because a certain amount of nutrients might produce a moderate amount of biomass, but produce negligible mar-ketable product due to small fruit size. Fruit size and qual-ity must be considered in the CNR concept for vegetables.

The CNR can be satisfied from many sources, includ-ing soil, water, air, organic matter, or fertilizer. For example, the CNR of potassium (K) can be supplied from K-containing minerals in the soil, from K retained by soil organic matter, or from K fertilizers.

The CNR for a crop is determined from field experi-ments that test the yield response to levels of added fertil-izer. For example, a watermelon study involving K might

be conducted on a soil which tests very low in extractable K. In this situation, the soil can be expected to contribute only a small amount of K for optimum watermelon growth and yield, and K must be supplied largely from fertilizer. The researcher plots the relationship between crop yield and fertilizer rate. The CNR is equivalent to the fertil-izer rate above which no significant increases in yield are expected. The CNR values derived from such experiments take into account factors such as fertilizer efficiencies of the soils. These efficiencies include fertilizer leaching or fertilizer nutrient fixing capability of the soil. If data are available from several experiments, then reliable estimates of CNR values can be made. Using the CNR concept when developing a fertilizer program will ensure optimum, eco-nomic yields while minimizing both pollution from over-fertilization and loss of yield due to underfertilization.

The CNR values are those amounts of nutrients needed to produce optimum, economic yields from a fertilization standpoint. It is important to remember that these nutrient amounts are supplied to the crop from both the soil and the fertilizer. The amounts are applied as fertilizers only when a properly calibrated soil test indicates very small extract-able amounts of these nutrients to be present in the soil. Therefore, soil testing must be conducted to determine the exact contribution from the soil to the overall CNR. Based on such tests, the amount of fertilizer that is needed to supplement the nutrition component of the native soil can be calculated (Tables 2 and 3).

Table 2. Mehlich-1 (double-acid) interpretations for vegetable crops in Florida.

Very low Low Medium High Very high

Element Parts per million soil

P 60

K 125

Mg1 60

Ca2 4001 Up to 40 lbs/a may be needed when soil test results are medium or lower2 Ca levels are typically adequate when > 300 ppm

Table 3. Interpretations of Mehlich-1 soil tests for micronutrients.

Soil pH (mineral soils only)

5.5 - 5.9 6.0 - 6.4 6.5 - 7.0

parts per million

Test level below which there may be a crop response to applied copper. 0.1 - 0.3 0.3 - 0.5 0.5

Test level above which copper toxicity may occur. 2.0 - 3.0 3.0 - 5.0 5.0

Test level below which there may be a crop response to applied manganese. 3.0 - 5.0 5.0 - 7.0 7.0 - 9.0

Test level below which there may be a crop response to applied zinc. 0.5 0.5 - 1.0 1.0 - 3.0

When soil tests are low or known deficiencies exists, apply per acre 5 lbs Mn, 2 lbs Zn, 4 lbs Fe, 3 lb Cu and 1.5 lbs B (higher rate needed for cole crops).


It is important that soil samples represent the field or management unit to be fertilized. A competent soil testing laboratory that uses calibrated methodologies should ana-lyze the samples. Not all laboratories can provide accurate fertilizer recommendations for Florida soils. The BMP pro-gram for vegetables requires the importance of calibrated soil test.

LIMING

Current University of Florida standardized recommen-dations call for maintaining soil pH between 6.0 and 6.5 (Table 4). However, some vegetables, such as watermelon, will perform normally at lower soil pH as long as large amounts of micronutrients are not present in the soil. A common problem in Florida has been overliming, resulting in high soil pH. Overliming and resulting high soil pH can tie up micronutrients and restrict their availability to the crop. Overliming also can reduce the accuracy with which a soil test can predict the fertilizer component of the CNR.

It is important, however, not to allow soil pH to drop below approximately 5.5 for most vegetable production, especially where micronutrient levels in the soil may be high due to a history of micronutrient fertilizer and micro-nutrient-containing pesticide applications. When soil pH

decreases in such soils, the solubility of micronutrients can increase to levels that may become toxic to plants.

Irrigation water from wells in limestone aquifers is an additional source of liming material usually not considered in many liming programs. The combination of routine additions of lime and use of alkaline irrigation water has resulted in soil pH greater than 8.0 for many sandy soils in south Florida. To measure the liming effect of irrigation, have a water sample analyzed for total bicarbonates and carbonates annually, and the results converted to pounds of calcium carbonate per acre. Include this information in your decisions concerning lime.

It should be evident that liming (Table 5), fertilization (Table 6), and irrigation programs are closely related to each other. An adjustment in one program will often influ-ence the other. To maximize overall production efficiency, soil and water testing must be made a part of any fertilizer management program.

MANURES

Waste organic products, including animal manures and composted organic matter, contain nutrients (Table 7) that can enhance plant growth. These materials decompose

Table 5. Liming materials.

Material FormulaAmount of Material to be used to equal 1 ton of Calcium Carbonate1

Neutralizing value2(%)

Calcium carbonate, calcite, hi-cal lime CaCO3 2,000lbs 100

Calcium-magnesium carbonate, dolomite CaCO3 MgCO3 1,850lbs 109

Calcium oxide, burnt lime CaO 1,100lbs 179

Calcium hydroxide, hydrated lime Ca(OH)2 1,500lbs 136

Calcium silicate, slag CaSiO3 2,350lbs 86

Magnesium carbonate MgCO3 1,680lbs 1191 Calcutated as (2000 x 100) / neutralizing value (%).2 The higher the neutralizing value, the greater the amount of acidity that is neutralized per unit weight of material.

Table 4. A general guideline to crop tolerance of mineral soil acidity.1

Slightly tolerant (pH 6.8-6.0) Moderately tolerant (pH 6.8-5.5) Very tolerant (pH 6.8-5.0)

Beet Leek Bean, snap Mustard Endive

Broccoli Lettuce Bean, lima Pea Potato

Cabbage Muskmelon Brussels sprouts Pepper Shallot

Cauliflower Okra Carrot Pumpkin Sweetpotato

Celery Onion Collard Radish Watermelon

Chard Spinach Corn Squash

Cucumber Strawberry

Eggplant Tomato

Kale Turnip1 From Donald N. Maynard and George J. Hochmuth, Knotts Handbook For Vegetable Growers, 4th edition (1997). Reprinted by permission of John Wiley & Sons, Inc.

when applied to the soil, releasing nutrients that vegetable crops can absorb and utilize in plant growth. The key to proper use of organic materials as fertilizers comes in the knowledge of the nutrient content and the decomposi-tion rate of the material. Many laboratories offer organic material analyses to determine specific nutrient contents. Growers contemplating using organic materials as fertil-izers should have an analysis of the material before deter-mining the rate of application. In the case of materials such as sludges, it is important to have knowledge about the type of sludge to be used. Certain classes of sludge are not appropriate for vegetable production, and in fact may not be permitted for land application. Decomposition rates of organic materials in warm sandy soils in Florida are

rapid. Therefore, there will be relatively small amounts of residual nutrients remaining for succeeding crops. Organic materials are generally similar to mixed chemical fertiliz-ers in that the organic waste supplies an array of nutrients, some of which may not be required on a particular soil. For example, P in poultry manure would not be required on a soil already testing high in phosphate. Usually appli-cation rates of organic wastes are determined largely by the N content. Organic waste materials can contribute to groundwater or surface water pollution if applied in rates in excess of the crop nutrient requirement for a particular vegetable crop. Therefore, it is important to understand the nutrient content and the decomposition rate of the organic waste material, and the P-holding capacity of the soil.

N, P, K, NUTRIENT SOURCES

Nitrogen can be supplied in both nitrate and ammo-niacal forms (Table 8). Nitrate is generally the preferred form for plant uptake in most situations, but ammoniacal N can be absorbed directly or after conversion to nitrate-N by soil microbes. Since this rate of conversion is reduced in cold, fumigated, or strongly acidic soils, it is recommended that under such conditions 25% to 50% of the N be supplied from nitrate sources. This ratio is not as critical for unfumigated or warm soils.

Phosphorus (P) can be supplied from several sources, including normal and triple superphosphate, diammo-nium phosphate, monopotassium phosphate, and mono-ammonium phosphate. All sources can be effective for plant nutrition on sandy soil. However, on soils that test very low in native micronutrient levels, diammonium phosphate in mixtures containing micronutrients reduces yields when banded in large amounts. Availability of P also can be reduced with use of diammonium phosphate compared to use of triple superphosphate. Negative effects of diammonium phosphate can be eliminated by using it for only a portion of the P requirement and by broadcasting this material in the bed.

Potassium (K) can also be supplied from several sources, including potassium chloride, potassium sulfate, potassium nitrate, and potassium-magnesium sulfate. If soil-test-predicted amounts of K fertilizer are adhered to, there should be no concern about the K source or its relative salt index.

CA, S, AND MG NUTRIENT SOURCES

The secondary nutrients calcium (Ca), sulfur (S), and magnesium (Mg) have not been a common problem in Florida. Calcium usually occurs in adequate supply for most vegetables when the soil is limed. If the Mehlich-1 soil Ca index is above 300 ppm, it is unlikely that there

Page 7Chapter 2: Soil and Fertilizer Management for Vegetable Production in Florida

Table 7. Average nutrient concentration of selected organic fertilizers.

N P2O5 K2O

Product % dry weight

Blood 13 2 1

Fish meal 10 6 0

Bone meal 3 22 0

Cotton seed meal 6 3 1.5

Peanut meal 7 1.5 1.2

Soybean meal 7 1.2 1.5

Dried commercial manure products

Stockyard 1 1 2

Cattle 2 3 3

Chicken 1.5 1.5 2

Table 6. Effect of some fertilizer materials on soil pH.

Fertilizer material

Approximate calcium carbonate equivalent (lb)1

Ammonium nitrate -1200

Ammonium sulfate -2200

Anhydrous ammonia -3000

Diammonium phosphate -1250 to -1550

Potassium chloride 0

Sodium-potassium nitrate +550

Nitrogen solutions -759 to -1800

Normal (ordinary) superphosphate 0

Potassium nitrate +520

Potassium sulfate 0

Potassium-magnesium sulfate 0

Triple (concentrated) superphosphate 0

Urea -17001 A minus sign indicates the number of pounds of calcium carbonate needed to

neutralize the acid formed when one ton of fertilizer is added to the soil.


Table 8. Some commonly used fertilizer sources.

Nutrient Fertilizer source Nutrient content (%)Nitrogen (N) Ammonium nitrate 34

Ammonium sulfate 21Calcium nitrate 15.5Diammonium phosphate 18Potassium nitrate (nitrate of potash) 13Urea 46Sodium-potassium nitrate (nitrate of soda-potash) 13

Phosphorus (P2O5) Normal (ordinary) superphosphate 20Triple (concentrated) superphosphate 46Diammonium phosphate 46Monopotassium phosphate 53

Potassium (K2O) Potassium chloride (muriate of potash) 60Potassium nitrate 44Potassium sulfate (sulfate of potash) 50Potassium-magnesium sulfate (sulfate of potash-magnesia) 22Sodium-potassium nitrate 14Monopotassium phosphate 34

Calcium (Ca) Calcic limestone 32Dolomite 22Gypsum 23Calcium nitrate 19Normal superphosphate 20Triple superphosphate 14

Magnesium (Mg) Dolomite 11Magnesium sulfate 10Magnesium oxide 55Potassium-magnesium sulfate 11

Sulfur (S) Elemental sulfur 97Ammonium sulfate 24Gypsum 18Normal superphosphate 12Magnesium sulfate 14Potassium-magnesium sulfate 22Potassium sulfate 18

Boron (B) Borax 11Fertibor1 14.9Granubor1 14.3Solubor1 20.5

Copper (Cu) Copper sulfate, monohydrate 35Copper sulfate, pentahydrate 25Cupric oxide 75Cuprous oxide 89Copper chloride 17Chelates (CuEDTA) 13(CuHEDTA) 6

Iron (Fe) Ferrous sulfate 20Ferric sulfate 20Chelates (FeHEDTA) 5 to 12

Manganese (Mn) Manganous sulfate 28Manganous oxide 68Chelates (MnEDTA) 5 to 12

Molybdenum (Mo) Ammonium molybdate 54Sodium molybdate 39

Zinc (Zn) Zinc sulfate 36Zinc oxide 80Zinc chloride 50Chelates (ZnEDTA) 6 to 14(ZnHEDTA) 6 to 10

1 Mention of a trade name does not imply a recommendation over similar materials.

will be a response to added Ca. Maintaining correct mois-ture levels in the soil by irrigation will aid in Ca supply to the roots. Calcium is not mobile in the plant; therefore, foliar sprays of Ca are not likely to correct deficiencies. It is difficult to place enough foliar-applied Ca at the growing point of the plant on a timely basis.

Sulfur deficiencies have seldom been documented for Florida vegetables. Sulfur deficiency would most likely occur on deep, sandy soils low in organic matter after leaching rains. If S deficiency has been diagnosed, it can be corrected by using S-containing fertilizers such as magnesium sulfate, ammonium sulfate, potassium sulfate, normal superphosphate, or potassium-magnesium sulfate. Using one of these materials in the fertilizer blend at levels sufficient to supply 30 to 40 lb S/A should prevent S defi-ciencies.

Magnesium deficiency may be a problem for vegetable production; however, when the Mehlich-1 soil-test index for Mg is below 15 ppm, 30-40 lb Mg/A will satisfy the Mg CNR. If lime is also needed, Mg can be added by using dolomite as the liming material. If no lime is needed, then the Mg requirement can be satisfied through use of magnesium sulfate or potassium-magnesium sulfate. Blending of the Mg source with other fertilizer(s) to be applied to the soil is an excellent way of ensuring uniform application of Mg to the soil.

MICRONUTRIENTS

It has been common in Florida vegetable production to routinely apply a micronutrient package. This practice has been justified on the basis that these nutrients were inex-pensive and their application appeared to be insurance for

high yields. In addition, there were few research data and a lack of soil-test calibrations to guide judicious application of micronutrient fertilizers. Compounding the problem has been the vegetable industry's use of micronutrient-contain-ing pesticides for disease control. Copper (Cu), manganese (Mn), and zinc (Zn) from pesticides have tended to accu-mulate in the soil.

This situation has forced some vegetable producers to overlime in an effort to avoid micronutrient toxicities. Data have now been accumulated which permit a more accu-rate assessment of micronutrient requirements (Table 3). Growers are encouraged to have a calibrated micronutrient soil test conducted and to refrain from (shotgun) micronu-trient fertilizer applications. It is unlikely that micronutri-ent fertilizers will be needed on old vegetable land, espe-cially where micronutrients are being applied regularly via recommended pesticides. A micronutrient soil test every 2 to 3 years will provide recommendations for micronutrient levels for crop production.

FOLIAR FERTILIZATION

Foliar fertilization should be thought of as a last resort for correcting a nutrient deficiency (Table 9). The plant leaf is structured in such a way that it naturally resists easy infiltration by fertilizer salts. Foliar fertilization most appropriately applies to micronutrients and not to macronu-trients such as N, P, and K. Foliar applications of N, P, and/or K are not needed where proper soil-directed fertilizer programs are in use. Leaves cannot absorb sufficient nutri-ents (without burning the leaves) to correct any deficiency. Some benefit from macronutrient foliar sprays probably results when nutrients are washed by rain or irrigation water off the leaf surface into the soil. The nutrient then may enters the plant via the roots. Amounts of macronutri-ents recommended on the label of most commercial foliar products are so minuscule compared to nutrition derived from the soil that benefit to the plant is highly unlikely. Additionally, fertilizer should only be added if additional yield results, and research with foliar-nutrient applications has not clearly documented a yield increase for vegetables.

In certain situations, temporary deficiencies of Mn, Fe, Cu, or Zn can be corrected by foliar application. Examples include vegetable production in winter months when soils are cool and roots cannot extract adequate amounts of micronutrients, and in cases where high pH (marl and Rockdale soils) fixes broadcast micronutrients into unavailable forms. Micronutrients are so termed because small or micro amounts are required to satisfy the CNR. Such micro amounts may be supplied adequately through foliar applications to correct a temporary defi-ciency.

Page 9Chapter 2: Soil and Fertilizer Management for Vegetable Production in Florida

Table 9. Recommendations for foliar applications of plant nutrients.

Nutrient SourceFoliar application (lb product per acre)

Boron Borax 2 to 5

Solubor1 1 to 1.5

Copper Copper sulfate 2 to 5

Iron Ferrous sulfate 2 to 3

Chelated iron 0.75 to 1

Manganese Manganous sulfate 2 to 4

Molybdenum Sodium molybdate 0.25 to 0.50

Zinc Zinc sulfate 2 to 4

Chelated zinc 0.75 to 1

Calcium Calcium chloride 5 to 10

Calcium nitrate 5 to 10

Magnesium Magnesium sulfate 10 to 151 Mention of a trade name does not imply a recommendation over similar

materials.


Boron is highly immobile in the plant. To correct defi-ciencies, small amounts of must be applied frequently to the young tissue or buds.

Any micronutrient should be applied only when a spe-cific deficiency has been clearly diagnosed. Do not make unneeded applications of micronutrients. There is a fine line between adequate and toxic amounts of these nutri-ents. Indiscriminate application of micronutrients may reduce plant growth and restrict yields because of toxic-ity. Compounding the problem is the fact that the micro-nutrients can accumulate in the soil to levels which may threaten crop production on that soil. An important part of any micronutrient program involves careful calculations of all micronutrients being applied, from all sources.

LIQUID VS. DRY FERTILIZER

There is no difference in response of crops to similar amounts of nutrients when applied in either liquid or dry form. Certain situations (use of drip irrigation or injection wheel) require clear or true solutions. However, sidedress applications of fertilizer can be made equally well with dry or liquid forms of nutrients.

The decision to use liquid or dry fertilizer sources should depend largely on economics and on the type of application equipment available. The cost per unit of nutri-ent (e.g., dollars per unit of actual N) and the combination of nutrients provided should be used in any decision-mak-ing process.

CONTROLLED-RELEASE FERTILIZERS (CRF)

Several brands of controlled-release fertilizers are avail-able for supplying N. Some vegetables increase in yield when controlled-release fertilizers, such as polymer-coated or sulfur-coated urea, or isobutylidene-diurea, are used to supply a portion of the N requirement. Although more expensive, these materials may be useful in reducing fertil-izer losses through leaching, in decreasing soluble salt dam-age, and in supplying adequate fertilizer for long-term crops such as strawberry or pepper. Controlled-release potassium fertilizers also have been demonstrated to be beneficial for several vegetables. It is essential to match the nutrient release pattern of the CRF with the crops uptake pattern.

SOLUBLE SALTS

Overfertilization or placement of fertilizer too close to the seed or root leads to soluble salt injury or fertilizer burn. Fertilizer sources differ in their capacity to cause soluble salt injury. Therefore, where there is a history of soluble salt problems, or where irrigation water is high in

soluble salts, choose low-salt index fertilizer sources, and broadcast or split-apply the fertilizer.

STARTER FERTILIZER

A true starter fertilizer is a soluble fertilizer, generally high in P, used for establishment of young seedlings and transplants. Starter fertilizers generally work best if a small amount of N and K is present along with the P. Starters represent a very small percentage of the overall fertilizer amount but are very important in establishing crops in cool, damp soils. They can be applied with the planter at 2 inches to the side of the seed and 2 inches deep or can be dissolved in the transplant water and applied in the furrow.

FERTILIZER PLACEMENT

Fertilizer rate and placement must be considered togeth-er. Banding low amounts of fertilizer too close to plants can result in the same amount of damage as broadcasting excessive amounts of fertilizer in the bed.

Because P movement in most soils is minimal, it should be placed in the root zone. Banding is generally considered to provide more efficient utilization of P by plants than broadcasting. This is especially true on the high P-fixing calcareous soils. Where only small amounts of fertilizer P are to be used, it is best to band. If broadcasting P, a small additional amount of starter P near the seed or transplant may improve early growth, especially in cool soils. The modified broadcast method where fertilizer is broadcast only in the bed area provides more efficient use of fertilizer than complete broadcasting.

Micronutrients can be broadcast with the P and incorpo-rated in the bed area. On the calcareous soils, micronutri-ents, such as Fe, Mn, and B, should be banded or applied foliarly.

Since N and, to a lesser extent, K are mobile in sandy soils, they must be managed properly to maximize crop uptake. Plastic mulch helps retain these nutrients in the soil. Under non-mulched systems, split applications of these nutrients must be used to reduce losses to leaching. Here, up to one-half of the N and K may be applied to the soil at planting or shortly after that time. The remaining fertilizer is applied in one or two applications during the early part of the growing season. Splitting the fertilizer applications also will help reduce the potential for soluble salt damage to the plants.

When using plastic mulch, fertilizer placement depends on the type of irrigation system (seep or drip) and on whether drip tubing or the liquid fertilizer injection wheel are to be used.

Chapter 2: Soil and Fertilizer Management for Vegetable Production in Florida

With seepage irrigation, all P and micronutrients should be incorporated in the bed. Apply 10 to 20% (but not more) of the N and K with the P. The remaining N and K should be placed in narrow bands on the bed shoulders, the number of which depend on the crop and number of rows per bed. These bands should be placed in shallow (2- to 21/2-inch-deep) grooves. This placement requires that adequate bed moisture be maintained so that capillarity is not broken. Otherwise, fertilizer will not move to the root zone.

Excess moisture can result in fertilizer leaching. Fertilizer and water management programs are linked. Maximum fertilizer efficiency is achieved only with close attention to water management.

Under either system above, fertilizing with drip irriga-tion or with a liquid fertilizer injection wheel might be suitable alternatives to the placement of all N and K in or on the bed prior to mulching.

In cases where supplemental sidedressing of mulched crops is needed, applications of liquid fertilizer can be made through the mulch with a liquid fertilizer injection wheel (Fig. 2-4). This implement is mounted on a tool bar and, using 30 to 40 psi pressure, injects fertilizer through a hole pierced in the mulch.

SUPPLEMENTAL FERTILIZER APPLICATIONS AND BMPS

In practice, supplemental fertilizer applications allow vegetable growers to numerically apply fertilizer rates higher than the standard IFAS recommended rates when growing conditions require to do so. The two main grow-ing conditions that may require supplemental fertilizer applications are leaching rains and extended harvest peri-ods. Applying additional fertilizer under the following three circumstances is part of the current IFAS fertilizer recommendations. Supplemental N and K fertilizer appli-cations may be made under three circumstances:

1. For vegetable crops grown on bare ground with seep-age irrigation and without drip irrigation, a 30 lbs/acre of N and /or 20 lbs/acre of K2O supplemental application is allowed after a leaching rain. A leach-ing rain occurs when it rains at least 3 inches in 3 days, or 4 inches in 7 days.

2. For all vegetable crops grown on any production system with one of the IFAS recommended irrigation scheduling methods, a supplemental fertilizer appli-cation is allowed when nutrient levels in the leaf or in the petiole fall below the sufficiency ranges. For bare ground production, the supplemental amount allowed is 30 lbs/acre of N and/or 20 lbs/acre of K2O. For drip irrigated crops, the supplemental amount

allowed is 1.5 to 2.0 lbs/A/day for N and/or K2O for one week.

3. Supplemental fertilizer applications are allowed when, for economical reasons, the harvest period has to be longer than the typical harvest period. When the results of tissue analysis and/or petiole testing are below the sufficiency ranges, a supplemental 30 lbs/acre N and/or 20 lbs/acre of K2O may be made for each additional harvest for bare ground production. For drip-irrigated crops, the supplemental fertilizer application is 1.5 to 2.0 lbs/A/day for N and/or K2O until the next harvest. A new leaf analysis and/or petiole analysis is required to document the need for additional fertilizer application for each additional harvest.

DOUBLE-CROPPING

Successive cropping of existing mulched beds is a good practice in order to make effective use of the polyethylene mulch and fumigant (Fig. 2-5). Double-cropping also can make use of residual fertilizer in the beds. If fertilizer-N applications and amounts were properly managed for the first crop, then there should be negligible amounts of N-fertilizer remaining in the beds. The practice of adding extra fertilizer to the beds when planting the first crop, thinking that this fertilizer will aid growth of the second crop is strongly discouraged. The extra fertilizer could con-tribute to soluble-salt damage to the first crop, and might still be leached from the root zone before the second crop is established.

A drip-irrigation system can be used to supply adequate nutrition to each crop in a double crop system. In most cases, only N and K may be needed for the second crop. Amounts of P and micronutrients (if any) used for the first crop will likely remain adequate for the second crop as well. Soil testing of a sample taken from the bed away from any fertilizer bands will help determine P or micro-nutrient needs, assuming that these nutrients were broad-cast in the bed prior to planting the first crop.

If N for the first crop was not applied in excess of the CNR, then the second crop should receive an amount of N equal to its own CNR. Potassium requirements of the second crop can be determined as for P in cases where the K for the first crop was incorporated in the bed. Potassium requirements for the second crop are more difficult to determine in cases where K for the first crop was banded. A moderate amount of residual K will probably remain in the bed from the application to the first crop. Therefore, K requirements for the second crop will likely be slightly less than the CNR value for the chosen crop.


Once the crop fertilizer requirements have been ascer-tained, the needed nutrition may be applied through the drip system. Where drip irrigation is not being used, a liquid injection wheel can be used to place fertilizer in the bed for the second crop.

LINEAR BED FOOT (LBF) SYSTEM FOR FERTILIZER APPLICATION

The University of Florida Extension Soil Testing Laboratory (ESTL) employs the Standardized Fertilizer Recommendation System in which all recommendations are expressed in lb/A. These fertilizer rates are based upon typical distances between bed centers for each crop (Table 10). Table 10 also indicates the typical number of planting rows within each bed. Conversions of fertilizer rates from lb/A to lb/100 LBF, based upon these typical bed spacings, are shown in Table 11.

Use of lb/100 LBF as a fertilizer rate assures that an appropriate rate of fertilizer will be applied, regardless of

the total number LBF in the cropped area. In other words, use of lb/A to express the fertilizer rate requires an adjust-ment based upon actual cropped area.

In reality, the goal is to provide a specific concentra-tion of nutrients to plant roots; that is, a specific amount of fertilizer within a certain volume of soil. This conceptual approach makes sense because most plant roots are con-fined within the volume of soil comprising the bed, espe-cially under the polyethylene in the full-bed mulch system.

See Table 11 for the conversion of fertilizer rates in lb/A to lb/100 LBF. This table is used correctly by 1) determin-ing the typical bed spacing from Table 10 for the crop; 2) locating the column containing the recommended fertilizer rate in lb/A; and 3) reading down the column until reach-ing the row containing the typical row spacing. This rate, in lb/100 LBF, should be used even in situations where the grower's bed spacing differs from the typical bed spacing.

IRRIGATION MANAGEMENT

Water management and fertilizer management are linked. Changes in one program will affect the efficiency of the other program. Leaching potential is high for the mobile nutrients such as N and K; therefore, over irriga-tion can result in movement of these nutrients out of the root zone. This could result in groundwater pollution in the case of N. The goal of water management is to keep the irrigation water and the fertilizer in the root zone. Therefore, growers need knowledge of the root zone of the particular crop so that water and fertilizer inputs can be managed in the root zone throughout the season.

With increased pressure on growers to conserve water and to minimize the potential for nutrient pollution, it becomes extremely important to learn as much as pos-sible about irrigation management. For more informa-tion, see Chapter 3, Principles and Practices of Irrigation Management for Vegetables, which is part of this publica-tion.

Table 10. Typical bed spacings for vegetables grown in Florida.

VegetableTypical Spacing1 (ft)

Rows of plants per bed

Broccoli 6 2

Muskmelon 5 1

Cabbage 6 2

Pepper 6 2

Cauliflower 6 2

Summer squash 6 2

Cucumber 6 2

Strawberry 4 2

Eggplant 6 1

Tomato 6 1

Lettuce 4 2

Watermelon 8 11 Spacing from the center of one bed to the center of an adjacent bed.

Table 11. Conversion of fertilizer rates in lb/A to lb/100 LBF.

Typical bed spacing (ft)

Recommended fertilizer rate in lb/A (N, P2O5, or K2O)

20 40 60 80 100 120 140 160 180 200

Resulting fertilizer rate in lb/100 LBF (N, P2O5, or K2O)

3 0.14 0.28 0.41 0.55 0.69 0.83 0.96 1.10 1.24 1.38

4 0.18 0.37 0.55 0.73 0.92 1.10 1.29 1.47 1.65 1.83

5 0.23 0.46 0.69 0.92 1.15 1.38 1.61 1.84 2.07 2.30

6 0.28 0.55 0.83 1.10 1.38 1.65 1.93 2.20 2.48 2.76

8 0.37 0.73 1.10 1.47 1.84 2.20 2.57 2.94 3.31 3.68


PLANT TISSUE ANALYSIS

Analysis of plants for nutrient concentration provides a good tool to monitor nutrient management programs. There are basically two approaches to plant tissue testing:stan-dard laboratory analyses based on dried plant parts; and the plant sap testing procedures. Both procedures have value in nutrient management programs for vegetable crops, each having its own advantages and disadvantages.

Standard laboratory analyses can be very accurate and are the most quantitative procedure. However, they can be time consuming for most diagnostic situations in the field. Standard laboratory analysis involves analyzing the most-recently-matured leaf of the plant for an array of nutrients. The resulting analyses are compared against published adequate ranges for that particular crop. Laboratory results that fall outside the adequate range for that nutrient may indicate either a deficiency or possibly a toxicity (espe-cially in the case of micronutrients). The most-recently-matured leaf serves well for routine crop monitoring and diagnostic procedures for most nutrients. However, for the immobile nutrients such as Ca, B, and certain other micro-nutrients, younger leaves are generally preferred.

Several plant sap quick test kits have been calibrated for N and K for several vegetables in Florida (Fig. 2-6). These testing kits analyze fresh plant sap for N and K. Quick test kits offer speed of analysis; however, these are less quanti-tative than standard laboratory procedures. However, quick tests are accurate enough and if properly calibrated are a valuable tool for on-the-spot monitoring of plant nutrient status with the goal of making fine adjustments in fertilizer application programs, especially for those involving drip irrigation.

DRIP IRRIGATION/FERTIGATION

Drip irrigation has become a very important water management tool for Florida vegetable growers (Fig. 2-7). Approximately 60,000 acres of vegetables are produced with drip irrigation yearly in Florida. Many drip irrigation users have turned to fertigation (applying nutrients through the irrigation tube) to gain better fertilizer management capability. In most situations, N and K are the nutrients injected through the irrigation tube. Split applications of N and K through irrigation systems offers a means to capture management potential and reduce leaching losses. Other nutrients, such as P and micronutrients, are usually applied to the soil rather than by injection. This is because chemi-cal precipitation can occur with these nutrients and the high calcium carbonate content of our irrigation water in Florida.

Nutrient management through irrigation tubes involves precise scheduling of N and K applications. Application

rates are determined by crop growth and resulting nutri-ent demand. Demand early in the season is small and thus rates of application are small, usually on the order of 1/2 to 3/4 lb of N or K2O per acre per day. As the crop grows, nutrient demand increases rapidly so that for some vegeta-ble crops such as tomato the demand might be as high as 2 lb of N or K2O per day. Schedules of N and K application have been developed for most vegetables produced with drip irrigation in Florida. Schedules for these crops are pre-sented in the crop chapters in this book.

SOIL PREPARATION

A well-prepared seed or planting bed is important for uniform stand establishment of vegetable crops. Old crop residues should be plowed down well in advance of crop establishment. A 6- to 8-week period between plow-ing down of green cover crops and crop establishment is recommended to allow the decay of the refuse. Freshly incorporated plant material promotes high levels of damp-ing-off organisms such as Pythium spp. and Rhizoctonia spp. Turning under plant refuse well in advance of crop-ping reduces damping-off disease organisms. Land should be kept disced if necessary to keep new weed cover from developing prior to cropping.

Chisel plowing is beneficial in penetrating and breaking tillage pan layers in fields. If plastic mulch culture is prac-ticed, debris and large undecayed roots will create problems in preparing good beds over which mulch will be applied.

BEDDING

Fields where seepage irrigation is used or fields prone to flooding should be cropped using raised beds. Beds generally range from 3 to 8 inches in height, with high beds of 6 to 8 inches preferred where risk of flooding is the greatest. Raised beds dry faster than if the soil was not bedded, requiring closer attention to irrigation manage-ment especially early in the season when root systems are limited. Raised beds promote early season soil warming resulting in somewhat earlier crops during cool seasons. Many raised beds covered with mulch in north Florida in sandy, well drained soils do not need to be as high as 6 to 8 inches as they do in poorly drained soils.

Bedding equipment may include single or double bed-ding discs, and curved bedding blades. After the soil is cut and thrown into a loose bed the soil is usually firmed with a bed press. In unmulched production the loosely formed bed may be leveled off at the top by dragging a board or bar across the bed top. Boarding-off the raised beds is common in unmulched watermelon production in central and northern Florida. Mulching requires a smooth, well-pressed bed for efficient heat transfer from black mulch


to the soil. Adequate soil moisture is essential in forming a good bed for mulching. Dry sandy soils will not form a good bed for a tight mulch application. Overhead irrigation is sometimes needed to supply adequate moisture to dry soils before bedding.

COVER CROPS

Cover crops between vegetable cropping seasons can provide several benefits. The use of cover crops as green manure can slightly increase soil organic matter during the growing season. Properties of soil tilth can also be improved with turning under good cover crops. The cover can reduce soil losses due to erosion from both wind and water. Many crops are effective at recycling nutrients left from previous crops. Recycling of nutrients is becoming an increasingly important issue in protecting groundwater quality.

The selection of a cover crop is based on the seasonal adaptation and intended use for the crops. Vegetable pro-duction in south Florida results in cover crops needed dur-ing the late spring and summer months. Summer grasses like sorghum or sudan/sorghum hybrids have been popular among Florida producers as a summer cover. Pearl millet is another grass crop providing excellent cover but is not as popular as sudan/sorghum. Both pearl millet and sudan/sorghum provide a vigorous tall crop with high biomass production and are excellent at competing with weeds. The cover crop selected should have resistance to nema-todes or at least serve as a relatively poor nematode host. Warm-season legumes such as velvet bean and hairy indigo have been noted for their resistance to nematodes. Hairy indigo has been unpopular because of its habit of reseed-ing. It also has hard seed and produces volunteers in later years. Alyceclover is another warm season legume with one variety, F1-3, having nematode resistance. Alyceclover produces an excellent quality hay for producers that can utilize hay from a cover crop.

In north Florida, vegetable crops are established in the spring and early fall. Cover crops are generally utilized during the winter months of November through March. Popular cool season grasses have included rye, wheat, oats, or ryegrass. The traditional crop rotation for water-melon growers has included the use of well-established bahia grass pastures followed by a crop of watermelon. The acreage of available bahia grass pastures for rotation has been reduced and these pastures are difficult to find for many growers. As a result, growers are being forced to more intensively crop fields. Cover crops would be help-ful in managing the land. When bahia grass sod is used for production, the extensive root system must be very well tilled well in advance of the cropping season to break up the clumps, especially if plastic mulch will be used. Deep

plowing is best to facilitate decomposition of the grass roots and stems.

WINDBREAKS

The use of windbreaks is an important cultural practice consideration in many vegetable crops and in most states in the United States. Windbreaks used in agriculture are barriers, either constructed or vegetative, of sufficient height to create a windless zone to their leeward or pro-tected side. Strong winds, even if a few hours in duration, can cause injury to vegetable crops by: whipping plants around, abrasion with solid particles (sand blasting), cold damage, and plant dessication. Windbreaks are especially important to protect young plants that are most susceptible to wind damage. Abrasion to plants from wind-blown sand is of concern in most of Florida where sandy soils are commonly used for production. Spring winds in Florida are expected each year. Many of the vegetable crops pro-duced in central and north Florida are at a young and very susceptible stage during these windy spring periods. Strips of planted rye are generally recommended for temporary windbreaks in those areas (Fig. 2-8). Sugarcane can also serve as a more permanent windbreak in South Florida (Fig. 2-9).

The primary reasons windbreaks have been used in veg-etable crops has been to reduce the physical damage to the crop from the whipping action of the wind and to reduce sand blasting. Young, unprotected vegetable crops stands can be totally lost from these two actions. Many Florida vegetable crops are grown using plastic mulch culture. Young cucurbit crops, such as watermelon and cantaloupe grown on plastic are especially susceptible to the whipping action of the wind. Vines of these crops eventually become anchored to the soil between mulched beds, however, young vines can be whipped around in circles for several days until they become anchored. The physical damage by whipping and sandblasting can reduce stand, break or weaken plants, open wounds which can increase disease, and reduce flowering and fruit set.

Windbreaks can also help conserve moisture for the crop. Effective windbreaks reduce the wind speed reach-ing the crops. This reduces both direct evaporation from the soil and transpiration losses from the plant. Improved moisture conditions can help in early season stand establishment and crop growth. Air temperatures around the crop can also be slightly modified by windbreaks. Temperature on the leeward side of the windbreaks can be slightly higher than if no windbreak were present. Early season crop growth is also greater when windbreaks are utilized. Workers in several states reported increased earliness when rye strips were effectively used as wind-breaks.


A field layout to include windbreaks must be properly designed to achieve the maximum benefit. The windbreaks should be positioned perpendicular to the prevailing winds. This determination is perhaps more difficult in Florida than most other states, however, windbreaks planned for protec-tion in the spring should generally protect against winds from the west or northwest. Wind protection is achieved as long as the barrier is a least three feet high, the vegetation is sufficiently dense, and is positioned perpendicular to the prevailing wind.

The height of the windbreak is the most important fac-tor in determining how far apart the strips must be located. Research on windbreaks has been conducted indicating wind protection is afforded to a distance of 6 to 20 times the height of the barrier. Field research with rye strips showed protection was afforded up to a distance of 10 times the height of the barrier. For example, a healthy crop of rye planted in a 5 to 8 ft wide strip using a grain drill and reaching a height of 3 ft would afford wind protection up to 30 ft from the rye strip. If the same rye strip reached a height of 4 ft it would afford protection up to 40 ft from the rye strip. These examples use the calculation of protec-tion afforded up to 10 times the height of an adequate rye strip.

Crops such as small grains, trees, shrubs, or sugarcane are permeable barriers in comparison to solid barriers such as smooth constructed walls. Solid barriers are less effective windbreaks than permeable barriers. Wind pass-ing over a solid barrier is deflected over and creates an area of turbulence on the protected side and returns to the ground quickly.

Another type of technology that can provide excellent protection from high winds is the use of plastic row tun-nels. Polyethylene or polypropylene materials are place over the plants in a row and held in place. Tunnels are popular for many vegetable crops, especially cucurbits such as cantaloupes. The cover is removed from cucurbits when the first female blooms appear to allow honeybees to pollinate the crops. Tunnels are generally used in conjunc-tion with rye strips because the tunnels have to be removed and once removed the crop is susceptible to wind.

The most widely used windbreak in vegetable crops across the United States is the rye strip method. Winter or cereal rye (Secale cereale) is the preferred small grain for this use because the seed is usually cheaper, it provides more growth under cold temperatures and results in the highest plant habit. In some cases the field is solid seeded and later tilled in only the narrow strips where the plastic mulch bed is applied. This leaves a narrow strip of rye between each bed or row and is generally a very effective windbreak design. This design can result in more difficul-ties in weed management if weeds emerge in the rye strips,

however, the rye can be managed with herbicide in certain crops.

The most common use of rye as a windbreak is plant-ing it into strips. Seeding rye should be done in the fall (October - December) for protection in a spring crop. The strips are typically 5-8 ft wide and planted with a grain drill. The windbreak is a valuable component of the crop-ping system and should be treated as such. A top dressing or two of a fertilizer (at least nitrogen) will promote suffi-cient early spring growth of the rye to maximize effective-ness as a windbreak. Unfertilized rye strips on low fertility soil will often result in poor, thin, short strips of rye that will be less effective as a windbreak.

The spacing of the rye strips every 30 to 40 feet allows them to also be used as drive roads or spray roads in the field. These are generally necessary in managing most vegetable crops and therefore the rye strips are not taking away cropped areas of the field.

When the rye strips have served their purpose, they can be removed by mowing, rototilling, or discing. If mow-ing is used in a plastic mulched field, the mower should not throw the rye stems into the plastic area because holes will be pierced in the mulch. One insect management con-cern in using rye strips in Florida is their attractiveness to thrips. Rye strips also seem to be an excellent environment for beneficial insects, especially lady beetles. If thrips need to be managed in the rye strips, the strips could be sprayed just before the rye is mowed or tilled out. Once the rye is destroyed, the thrips migrate to the crops so control would be more effective while they are still on the rye strips.

Chapter 3.Principles and Practices of Irrigation Management for VegetablesE.H. Simonne, M.D. Dukes and L. Zotarelli

This section contains basic information on vegetable water use and irrigation management, along with some references on irrigation systems. Proper water manage-ment planning must consider all uses of water, from the source of irrigation water to plant water use. Therefore, it is very important to differentiate between crop water requirements and irrigation or production system water requirements. Crop water requirements refer to the actual water needs for evapotranspiration (ET) and plant growth, and primarily depend on crop development and climatic factors which are closely related to climatic demands. Irrigation requirements are primarily determined by crop water requirements, but also depend on the characteristics of the irrigation system, management practices and the soil characteristics in the irrigated area.

BEST MANAGEMENT PRACTICES (BMP) FOR IRRIGATION

BMPs have historically been focused on nutrient man-agement and fertilizer rates. However, as rainfall or irri-gation water is the vector of off-site nutrient movement of nitrate in solution and phosphate in sediments as well as other soluble chemicals, proper irrigation management directly affects the efficacy of a BMP plan. The irrigation BMPs in the Water Quality/Quantity Best Management Practices for Florida Vegetable and Agronomic Crops (accessible at www.floridaagwaterpolicy.com) manual cover all major aspects of irrigation such as irrigation system design, system maintenance, erosion control, and irrigation scheduling.

USES OF IRRIGATION WATER

Irrigation systems have several uses in addition to water delivery for crop ET. Water is required for a preseason operational test of the irrigation system to check for leaks and to ensure proper performance of the pump and power plant. Irrigation water is also required for field prepara-tion, crop establishment, crop growth and development, within-season system maintenance, delivery of chemicals, frost protection, and other uses such as dust control.

Field PreparationField preparation water is used to provide moisture

to the field soil for tillage and bed formation. The water used for field preparation depends on specific field cul-tural practices, initial soil moisture conditions, the depth to the natural water table, and the type of irrigation sys-tem. Drip-irrigated fields on sandy soils often require an additional irrigation system for field preparation because drip

Florida Vegetable Handbook 2011

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