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AUTHOR
Eric P. Prostko
Professor and Extension Weed Specialist
University of Georgia

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TABLE OF CONTENTS
  1. Herbicide Effects on Field Corn Yield in A High Input Environment
  2. Georgia Field Corn Production
  3. Something to think about?
  4. RR1 Field Corn (Pioneer 2023BVT) Yield Response to Roundup WeatherMax
  5. ‘DKC 64-69’ Yield Response to POST Applications of Steadfast Q
  6. Materials and Methods
  7. Test 1 Herbicides
  8. Test 2 Corn Info
  9. High Input Environment - 2014
  10. Results
  11. Figure 1. Herbicide Effects on Field Corn Yield in a High Input Environment
  12. Figure 2. Herbicide Effects on Field Corn Ear #/A in a High Input Environment
  13. Figure 3. Herbicide Effects on Field Corn Ear Weight in a High Input Environment
  14. Roundup + Sandea + Atrazine??????
  15. Figure 4. Roundup W-Max + Atrazine + AMS Xtra Timing Effects on Field Corn Yield in a High Input Environment
  16. Figure 5. Roundup W-Max + Atrazine + AMS Xtra Timing Effects on Field Corn Ear #/A in a High Input Environment
  17. Figure 6. Roundup W-Max + Atrazine + AMS Xtra Timing Effects on Field Corn Ear Weight in a High Input Environment
  18. Summary
  19. Acknowledgements
  20. Question/Comments



SLIDE CONTENTS
  1. E.P. Prostko and O.W. Carter Dept. Crop & Soil Sciences Herbicide Effects on Field Corn Yield in A High Input Environment
  2. Georgia Field Corn Production Source: NASS
  3. Something to think about? Some GA growers are pushing yield limits (250+ Bu/A) 75%-80% irrigated weed science researcher (me) typically does not make 225+ Bu/A yields At lower yield/input levels, are herbicide stresses masked by other stresses? At higher yield/input levels (i.e. most stresses are controlled), what about herbicides?
  4. RR1 Field Corn (Pioneer 2023BVT) Yield Response to Roundup WeatherMax P = 0.2275 CV = 3.8 Applied 28 DAP, V5, 5” tall corn All trts included Aatrex 4L @ 64 oz/A + COC @ 1% v/v Bu/A
  5. ‘DKC 64-69’ Yield Response to POST Applications of Steadfast Q (RUWM @ 22 oz/A, ATZ @ 64 oz/A, STDQ @ 1.5 or 3 oz/A) P = 0.5017 CV = 1.75 Applied 28 DAP V4, 6” tall corn Bu/A
  6. Materials and Methods Brooks County, GA Small plot techniques Test 1 7 herbicides 1 timing (V3-V4, 4” tall, 21 DAP) Test 2 1 herbicide RUWM (32 oz/A) + ATZ (48 oz/A) + AMS (2.5% v/v) 4 timings V2-V3, V4, V6-V7, V7-V8
  7. Test 1 Herbicides *RUWM = Roundup WeatherMax, NIS = Adept, COC = Reliable
  8. Test 2 Corn Info
  9. High Input Environment - 2014 Pioneer 1685 Planted March 22 Tifton loamy sand Twin Row (48”-15”) 42,000 seed/A 340-60-150/A 5-6 apps of N via pivot 3 fungicides Approach – V12 (1 app) Approach/Prima + B (2 apps) 3 insecticides Bifenthrin (with fungicides) ~27” rainfall (March 22 – Aug 12) 9” supplemental irrigation (pivot)
  10. Results
  11. Figure 1. Herbicide Effects on Field Corn Yield in a High Input Environment CN-01-14 Applied 21 DAP V3-V4 Pioneer 1685 P = 0.4165 CV = 12.32
  12. Figure 2. Herbicide Effects on Field Corn Ear #/A in a High Input Environment CN-01-14 Applied 21 DAP V3-V4 Pioneer 1685 P = 0.8593 CV = 5.66
  13. Figure 3. Herbicide Effects on Field Corn Ear Weight in a High Input Environment CN-01-14 Applied 21 DAP V3-V4 Pioneer 1685 P = 0.1126 CV = 9.17
  14. Roundup + Sandea + Atrazine?????? (26 DAT) - 2014
  15. Figure 4. Roundup W-Max (32 oz/A) + Atrazine (48 oz/A) + AMS Xtra (2.5% v/v) Timing Effects on Field Corn Yield in a High Input Environment Pioneer 1685 P = 0.1430 CV = 6.56
  16. Figure 5. Roundup W-Max (32 oz/A) + Atrazine (48 oz/A) + AMS Xtra (2.5% v/v) Timing Effects on Field Corn Ear #/A in a High Input Environment Pioneer 1685 P = 0.8757 CV = 8.0
  17. Figure 6. Roundup W-Max (32 oz/A) + Atrazine (48 oz/A) + AMS Xtra (2.5% v/v) Timing Effects on Field Corn Ear Weight in a High Input Environment Pioneer 1685 P = 0.5334 CV = 6.48
  18. Summary No effect of herbicides or timing in high input environment Encouraging growers to be done by V5 But…… Sandea issues??? V7-V8 applications
  19. Acknowledgements Randy Dowdy Brooks County, GA Winner of National Corn Growers Association Yield Contest (Irrigated) 2011 = 352.3 Bu/A (2nd place) 2012 = 372.3 Bu/A (1st Place) 2013 = 405.1 Bu/A (2nd Place) 2014 = 503.7 Bu/A (1st Place)
  20. Question/Comments eprostko@uga.edu www.gaweed.com