Janice Reed and Donn Thill University of Idaho Janice Reed and Donn Thill University of Idaho...

Janice Reed and Donn Thill

University of Idaho

Janice Reed and Donn Thill

University of Idaho

Chemical and Mechanical Suppression of Kentucky Bluegrass Stands In An

Alternate Year Production System

Chemical and Mechanical Suppression of Kentucky Bluegrass Stands In An

Alternate Year Production System

IntroductionIntroduction

• Need to develop alternative residue management systems–Maintain stand longevity– Economically sustainable

• Suppression with herbicides in alternate year production– Year 1: Suppression, regrowth– Year 2: Seed production, mechanical

residue removal (mow, harrow)

• Need to develop alternative residue management systems–Maintain stand longevity– Economically sustainable

• Suppression with herbicides in alternate year production– Year 1: Suppression, regrowth– Year 2: Seed production, mechanical

residue removal (mow, harrow)

• Increase yield– Stand thinning– Moisture retention

• Residue decomposition

• Increase yield– Stand thinning– Moisture retention

• Residue decomposition

Herbicide Suppression of Bluegrass and Alternate Year

Seed Production

Herbicide Suppression of Bluegrass and Alternate Year

Seed Production

ObjectiveObjective

• Roundup Timing Studies

• Herbicide Comparison Study

Determine the optimum herbicide and herbicide application time to predictably suppress Kentucky bluegrass stands

• Roundup Timing Studies

• Herbicide Comparison Study

Determine the optimum herbicide and herbicide application time to predictably suppress Kentucky bluegrass stands

Roundup Timing StudiesRoundup Timing Studies

Jacklin Seed research site Nezperce, ID

• Palouse – early Newport – intermediate Nublue – late

• 2001-2002 and 2002-2003

• 10 by 30 ft, RCB, 4 reps

• Plots burned prior to trial establishment

Jacklin Seed research site Nezperce, ID

• Palouse – early Newport – intermediate Nublue – late

• 2001-2002 and 2002-2003

• 10 by 30 ft, RCB, 4 reps

• Plots burned prior to trial establishment

• Roundup Ultra at 1qt/A + AMS 8.5 lb/100 gal March 20, 27, April 5, 12, and 19, 2001 March 29, April 4, 11, 19, and 25, 2002 Untreated check

• Visual evaluation of suppression and regrowth

• Untreated checks harvested and burned year 1

• All plots fertilized fall of year 1

• Roundup Ultra at 1qt/A + AMS 8.5 lb/100 gal March 20, 27, April 5, 12, and 19, 2001 March 29, April 4, 11, 19, and 25, 2002 Untreated check


• Untreated checks harvested and burned year 1

• All plots fertilized fall of year 1

Roundup Timing StudiesRoundup Timing Studies

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Nublue Newport Palouse

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03/29/02 04/04/02 04/11/02 04/19/02 04/25/02

2002/2003 Roundup Timing Study 2003 Cover

2002/2003 Roundup Timing Study 2003 Cover

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UntreatedUntreated

Nublue May 2003Nublue May 2003

Palouse May 2003Palouse May 2003

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4/19/024/19/024/25/024/25/02UntreatedUntreated

4/11/024/11/02 4/4/024/4/02 3/29/023/29/02

4/25/024/25/02 4/19/024/19/02

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Nublue Newport Palouse

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2002/2003 Roundup Timing Study 2003 Seed Yield

2002/2003 Roundup Timing Study 2003 Seed Yield

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• Suppression is cultivar specific

• Stand suppression with Roundup is variable

• Recovery from Roundup suppression was best with a later-maturing variety

• Recovery from suppression and yield generally were best when Roundup was applied earlier

• Suppression is cultivar specific

• Stand suppression with Roundup is variable

• Recovery from Roundup suppression was best with a later-maturing variety

• Recovery from suppression and yield generally were best when Roundup was applied earlier

2002/2003 Roundup Timing Study Summary

2002/2003 Roundup Timing Study Summary

• Mosman farm near Craigmont, ID• Residue was not removed; plots mowed and

harrowed prior to plot establishment• 8 by 30 ft, split-plot, 4 reps, untreated check• 6 herbicides, 3 timings at 2-week intervals– Roundup Ultra 1.6 pt/A– Gramoxone Extra 1.6 pt/A– Plateau 0.5 pt/A– Liberty 2 pt/A– Maverick 0.66 oz/A– Assure II 0.5 pt/A

• Mosman farm near Craigmont, ID• Residue was not removed; plots mowed and

harrowed prior to plot establishment• 8 by 30 ft, split-plot, 4 reps, untreated check• 6 herbicides, 3 timings at 2-week intervals– Roundup Ultra 1.6 pt/A– Gramoxone Extra 1.6 pt/A– Plateau 0.5 pt/A– Liberty 2 pt/A– Maverick 0.66 oz/A– Assure II 0.5 pt/A

Herbicide Suppression Study 2002/2003


* All herbicides applied with the recommended spray additives

* All herbicides applied with the recommended spray additives

• Quantum Leap: 1 yr old stand Short , aggressive, long floral induction April 4, 19, and May 1, 2002

• Newport: 10 yr old stand Tall, less aggressive, short floral induction April 19, May 1, and 16, 2002


• Untreated checks harvested and burned in 2002

• All plots fertilized fall 2002

• Quantum Leap: 1 yr old stand Short , aggressive, long floral induction April 4, 19, and May 1, 2002

• Newport: 10 yr old stand Tall, less aggressive, short floral induction April 19, May 1, and 16, 2002


• Untreated checks harvested and burned in 2002

• All plots fertilized fall 2002

Herbicide Suppression Study MethodsHerbicide Suppression Study Methods

Herbicide Suppression Study Newport Yield 2003

Herbicide Suppression Study Newport Yield 2003

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Gramoxone Plateau Liberty Assure Maverick

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4/19/02 5/1/02 5/16/02 Untrt

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Herbicide Suppression Study Quantum Leap Yield 2003

Herbicide Suppression Study Quantum Leap Yield 2003

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Gramoxone Plateau Liberty Assure Maverick

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Quantum LeapMay 2002


UntreatedUntreated

UntreatedUntreated

Assure II 4/4Assure II 4/4 Assure II 4/19Assure II 4/19

4/4 Roundup 4/194/4 Roundup 4/19

Gramoxone 4/19Gramoxone 4/19Gramoxone 5/1Gramoxone 5/1

UntreatedUntreated

UntreatedUntreatedGramoxone 5/1Gramoxone 5/1

Assure II 4/4Assure II 4/4 Assure II 4/19Assure II 4/19

Gramoxone 4/19Gramoxone 4/19

4/4 Roundup 4/194/4 Roundup 4/19





• Greencreek- Rambo, Worley- Cenex 22• Residue not removed; plots mowed and

harrowed prior to plot establishment• 8 by 30 ft, split-plot, 4 reps, untreated check• 5 herbicides at 3 times– Roundup Ultra 1.6 pt/A– Gramoxone Extra 1.6 pt/A– Plateau 0.5 pt/A– Liberty 2 pt/A– Assure II 0.5 pt/A

• Mow at 3 times– Vegatative, heading, early flower

• Greencreek- Rambo, Worley- Cenex 22• Residue not removed; plots mowed and

harrowed prior to plot establishment• 8 by 30 ft, split-plot, 4 reps, untreated check• 5 herbicides at 3 times– Roundup Ultra 1.6 pt/A– Gramoxone Extra 1.6 pt/A– Plateau 0.5 pt/A– Liberty 2 pt/A– Assure II 0.5 pt/A

• Mow at 3 times– Vegatative, heading, early flower

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Gramoxone Plateau Liberty Assure II

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Herbicide Suppression Study Rambo Cover 2003

Herbicide Suppression Study Rambo Cover 2003

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Gramoxone Plateau Liberty Assure II

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Herbicide Suppression Study Cenex 22 Cover 2003

Herbicide Suppression Study Cenex 22 Cover 2003

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Herbicide Suppression Study Summary

Herbicide Suppression Study Summary

• Bluegrass suppression with herbicides varies with cultivar and application time

• Yield from plots treated with Gramoxone, Liberty, and Assure II was equal to or greater than the untreated

• Bluegrass suppression with herbicides varies with cultivar and application time

• Yield from plots treated with Gramoxone, Liberty, and Assure II was equal to or greater than the untreated

Janice Reed and Donn Thill University of Idaho Janice Reed and Donn Thill University of Idaho...

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