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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. Low-Density Polyethylene Mulch is a Great Physical Weed Control Barrier…. Low-Density Polyethylene
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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
Low-Density Polyethylene Mulch is a Great Physical Weed Control Barrier…
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
…But Nutsedges Will Pierce This Physical Barrier and Interfere With Crop Growth
… 40 Acre Watermelon Field Without Methyl Bromide Treatment X X X
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.
16 Wks • 59 cm Diam. • 23 cm Deep • 1.25 mil • Drip Irrigation Black Mulch No-Mulch Clear Mulch Temporal Patterns of Emergence
Nutsedge Shoots/Pot by mulch and species 146 15 6 2
Previous Studies: Nutsedge Population With and Without Black LDPE Mulch
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
Nutsedge Shoots/Pot Below Mulch by mulch and species 73 39 14 12 58% 92% 80% 95%
Nutsedge Tubers/Pot by mulch and species 366 188 179 47
How does mulch affect nutsedge patch expansion in the field?
There were differences due to mulch! Black Plastic Clear Plastic No Plastic Purple Nutsedge
12.7 cm 12.7 cm Grid System Used To Quantify Yellow Nutsedge And Purple Nutsedge(<16 WAP) Shoot Populations
Grid System (12.7 cm X 12.7 cm)Used To Quantify Purple Nutsedge Shoot Populations After 8 WAP 12.7 cm
Unable To Evaluate Purple Nutsedge In Clear Mulch: This Is The Only Plot That Survived Establishment
Purple Nutsedge Shoots/Patch 3439 1548 1858 794
Purple Nutsedge Non-Mulched Control 16 Weeks After Planting
Purple Nutsedge Non-Mulched Control 24 Weeks After Planting
Purple Nutsedge Non-Mulched Control 32 Weeks After Planting
Purple Nutsedge Non-Mulched Control 60 Weeks After Planting
16 WAP 24 WAP Purple Nutsedge Non-Mulched Control 32 WAP 60 WAP
Purple Nutsedge Black LDPE Mulch 16 Weeks After Planting
Purple Nutsedge Black LDPE Mulch 24 Weeks After Planting
Purple Nutsedge Black LDPE Mulch 32 Weeks After Planting
Purple Nutsedge Black LDPE Mulch 60 Weeks After Planting
16 WAP 24 WAP Purple Nutsedge Black LDPE Mulch 32 WAP 60 WAP
32 Weeks After Planting Purple Nutsedge Black LDPE Mulch Purple Nutsedge Non-mulched control
60 Weeks After Planting Purple Nutsedge Black LDPE Mulch Purple Nutsedge Non-mulched control
Purple Nutsedge Patch Area 22.1 16.1 11.6 8.1
Clear Plastic Black Plastic No Plastic Yellow Nutsedge: a different growth pattern
Yellow nutsedge was sensitive to cool autumn temperatures, therefore there is no data beyond 24 WAP
Yellow Nutsedge Shoots/Patch 208 137 73 & 76 36 & 39
Yellow Nutsedge Patch Expansion: 24 Weeks of growth from a single tuber Patch Area: 0.18 m2 177 Yellow Nutsedge Shoots
Number of Yellow Nutsedge Quadrats/Patch 11.0 (0.18 m2) 9.3 5.3
Yellow nutsedge Purple nutsedge 0.18 m2 5.5 m2 24 WAP Non-mulched controls
Conclusions: Greenhouse • Non-mulched control: Relative to Purple Nutsedge, Yellow Nutsedge produced: • 9x’s more shoots • 7x’s 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
Conclusions: Field • Purple Nutsedge in Black Mulch Plots: • 2x’s MORE shoots at 32 and 60 WAP compared to Non-Mulched Control • 2x’s MORE patch area at 32 and 60 WAP compared to the Non-Mulched Control • Yellow Nutsedge in Black Mulch Plots: • 3x’s LESS shoots at 16 and 24 WAP compared to Non-Mulched Control • 2x’s LESS patch size (in terms of quadrat #’s) compared to Non-Mulched Control
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.
Acknowledgements • Eddie Sklany (Study Coordinator) • Aaron Wise • Dustin Taylor • John Bennet • Amy Davis • Stefanie Cross Contact Information: Twebster@tifton.usda.gov http://www.cpes.peachnet.edu/cpmru/ http://gaweed.com