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AUTHOR
Theodore M. Webster
Crop Protection and Management Research Unit
USDA-ARS
Tifton, GA

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TABLE OF CONTENTS
  1. Should I Stay or Should I Grow? The nutsedge dilemma in polyethylene mulch systems
  2. Low-Density Polyethylene Mulch is a Great Physical Weed Control Barrier
  3. In the absence of Methyl Bromide, Mulch will be a critical component of Weed Management Systems
  4. Nutsedges will pierce this physical barrier and interfere with crop growth
  5. 40 acre watermelon field without Methyl Bromide treatment
  6. Hypotheses
  7. Temporal patterns of emergence
  8. Nutsedge shoots/pot: by mulch and species
  9. Previous Studies: nutsedge population with and without black LDPE mulch
  10. Purple Nutsedge growing under black LDPE
  11. Nutsedge shoots/pot below mulch: by mulch and species
  12. Soil sieved for tubers
  13. Nutsedge tubers/pot: by mulch and species
  14. How does mulch affect nutsedge patch expansion in the field?
  15. There were differences due to mulch
  16. Grid system used to quantify Yellow and Purple Nutsedge shoot populations
  17. Grid system used to quantify Purple Nutsedge shoot populations after 8 WAP
  18. Unable to evaluate Purple Nutsedge in clear mulch
  19. Purple Nutsedge shoots/patch
  20. Purple Nutsedge Non-Mulched Control: 16 WAP
  21. Purple Nutsedge Non-Mulched Control: 24 WAP
  22. Purple Nutsedge Non-Mulched Control: 32 WAP
  23. Purple Nutsedge Non-Mulched Control: 60 WAP
  24. Purple Nutsedge Non-Mulched Control
  25. Purple Nutsedge Black LDPE Mulch: 16 WAP
  26. Purple Nutsedge Black LDPE Mulch: 24 WAP
  27. Purple Nutsedge Black LDPE Mulch: 32 WAP
  28. Purple Nutsedge Black LDPE Mulch: 60 WAP
  29. Purple Nutsedge Black LDPE Mulch
  30. Purple Nutsedge Black LDPE Mulch vs Non-Mulched Control: 32 WAP
  31. Purple Nutsedge Black LDPE Mulch vs Non-Mulched Control: 60 WAP
  32. Purple Nutsedge Patch Area
  33. Yellow Nutsedge: a different growth pattern
  34. Yellow Nutsedge was sensitive to cool autumn temperatures
  35. Yellow Nutsedge Shoots/Patch
  36. Yellow Nutsedge Patch Expansion: 24 weeks of growth
  37. Number of Yellow Nutsedge Quadrats/Patch
  38. Yellow Nutsedge vs. Purple Nutsedge: 24 WAP Non-Mulched Controls
  39. Conclusions: Greenhouse
  40. Conclusions: Field
  41. Take Home Message
  42. Acknowledgements



SLIDE CONTENTS
  1. Should I Stay or Should I Grow? The nutsedge dilemma in polyethylene mulch systems Theodore M. Webster Crop Protection and Management Research Unit USDA-ARS, Tifton, GA
  2. Low-Density Polyethylene Mulch is a Great Physical Weed Control Barrier
  3. Low-Density Polyethylene Mulch is a Great Physical Weed Control Barrier In the Absence of Methyl Bromide, Mulch Will Be a Critical Component of Weed Management Systems
  4. But Nutsedges Will Pierce This Physical Barrier and Interfere With Crop Growth
  5. X X X 40 Acre Watermelon Field Without Methyl Bromide Treatment
  6. Hypotheses: Polyethylene mulch will hinder nutsedge shoot growth, tuber production, and patch expansion Purple and yellow nutsedge will be affected by mulches in a similar manner Purple and yellow nutsedge will have similar growth habits in the absence of mulches.
  7. Black Mulch Clear Mulch No-Mulch Temporal Patterns of Emergence 16 Wks 59 cm Diam. 23 cm Deep 1.25 mil Drip Irrigation
  8. Nutsedge Shoots/Pot by mulch and species 146 15 6 2
  9. Previous Studies: Nutsedge Population With and Without Black LDPE Mulch
  10. Purple Nutsedge Growing Under Black LDPE Minimal Shoot Penetration Through The Mulch (shoots growing under black mulch in previous slide) So we evaluated nutsedge shoot numbers trapped beneath mulch in the greenhouse study
  11. Nutsedge Shoots/Pot Below Mulch by mulch and species 73 39 14 12 58% 92% 80% 95%
  12. Soil Sieved for tubers
  13. Nutsedge Tubers/Pot by mulch and species 366 188 179 47
  14. How does mulch affect nutsedge patch expansion in the field?
  15. Purple Nutsedge Black Plastic Clear Plastic No Plastic There were differences due to mulch!
  16. Grid System Used To Quantify Yellow Nutsedge And Purple Nutsedge (<16 WAP) Shoot Populations
  17. Grid System (12.7 cm X 12.7 cm) Used To Quantify Purple Nutsedge Shoot Populations After 8 WAP 12.7 cm
  18. Unable To Evaluate Purple Nutsedge In Clear Mulch: This Is The Only Plot That Survived Establishment
  19. Purple Nutsedge Shoots/Patch 1548 794 3439 1858
  20. 16 Weeks After Planting Purple Nutsedge Non-Mulched Control
  21. 24 Weeks After Planting Purple Nutsedge Non-Mulched Control
  22. 32 Weeks After Planting Purple Nutsedge Non-Mulched Control
  23. 60 Weeks After Planting Purple Nutsedge Non-Mulched Control
  24. 16 WAP 24 WAP 32 WAP 60 WAP Purple Nutsedge Non-Mulched Control
  25. 16 Weeks After Planting Purple Nutsedge Black LDPE Mulch
  26. 24 Weeks After Planting Purple Nutsedge Black LDPE Mulch
  27. 32 Weeks After Planting Purple Nutsedge Black LDPE Mulch
  28. 60 Weeks After Planting Purple Nutsedge Black LDPE Mulch
  29. 16 WAP 24 WAP 32 WAP 60 WAP Purple Nutsedge Black LDPE Mulch
  30. 32 Weeks After Planting Purple Nutsedge Non-mulched control Purple Nutsedge Black LDPE Mulch
  31. 60 Weeks After Planting Purple Nutsedge Non-mulched control Purple Nutsedge Black LDPE Mulch
  32. Purple Nutsedge Patch Area 16.1 8.1 22.1 11.6
  33. Yellow Nutsedge: a different growth pattern Black Plastic Clear Plastic No Plastic
  34. Yellow nutsedge was sensitive to cool autumn temperatures, therefore there is no data beyond 24 WAP
  35. Yellow Nutsedge Shoots/Patch 208 73 & 76 36 & 39 137
  36. Yellow Nutsedge Patch Expansion: 24 Weeks of growth from a single tuber Patch Area: 0.18 m2 177 Yellow Nutsedge Shoots
  37. Number of Yellow Nutsedge Quadrats/Patch 11.0 (0.18 m2) 9.3 5.3
  38. 24 WAP Non-mulched controls Yellow nutsedge Purple nutsedge 0.18 m2 5.5 m2
  39. Conclusions: Greenhouse Non-mulched control: Relative to Purple Nutsedge, Yellow Nutsedge produced: 9xs more shoots 7xs more tubers Mulches: Reduced Yellow Nutsedge Shoot #s by 96% Tuber #s by 50% Differences in purple nutsedge shoot #s and tuber #s could not be detected among treatments
  40. Conclusions: Field Purple Nutsedge in Black Mulch Plots: 2xs MORE shoots at 32 and 60 WAP compared to Non-Mulched Control 2xs MORE patch area at 32 and 60 WAP compared to the Non-Mulched Control Yellow Nutsedge in Black Mulch Plots: 3xs LESS shoots at 16 and 24 WAP compared to Non-Mulched Control 2xs LESS patch size (in terms of quadrat #s) compared to Non-Mulched Control
  41. Take Home Message: Yellow Nutsedge: Growth SUPPRESSED by black mulch Does not distribute itself far from the mother tuber Confirms the predictions of a spatial model of yellow nutsedge growth: farming operations are the main cause of yellow nutsedge dispersal in the field (Schippers et al. 1993). Purple nutsedge: Growth PROMOTED by black mulch Well suited to distribute itself through its environment.
  42. Acknowledgements Contact Information: Twebster@tifton.usda.gov http://www.cpes.peachnet.edu/cpmru/ http://gaweed.com Eddie Sklany (Study Coordinator) Aaron Wise Dustin Taylor John Bennet Amy Davis Stefanie Cross