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Weed suppressive cropping systems

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Matthew Fidelibus
Matthew Fidelibus

Row orientation in vineyards can affect weed management by influencing the light environment for weeds. A study examined the effects of east-west versus north-south row orientation on the growth of black nightshade weeds under grape vines. Weeds in east-west rows received less light and produced fewer seeds than those in north-south rows. Specifically, weeds in east-west rows produced 20% fewer seeds. The results suggest vineyard design can help manage weeds by manipulating their light environment through row orientation.

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Vineyard design and weed suppression: an example with black nightshade (Solanum nigrum) Matthew Fidelibus Extension Specialist Department of Viticulture and Enology University of California, Davis
Challenges to Weed Control in San Joaquin Valley (SJV) Vineyards ? Economic: Profit margins are slim and the ¡®cost¡¯ of weeds in mature vineyards is uncertain ? Environmental: ¨C Air and water pollution are major problems in the SJV ¨C Regulation of dust emissions may curtail mechanical controls. ¨C Herbicide use restricted in some SJV vineyards to protect groundwater ? Biological: Many weed species are resistant to common herbicides
Weed control a low priority in some raisin vineyards Photo courtesy of Kurt Hembree, UCCE
Dust emissions from vehicles, equipment and wind are regulated
Herbicide resistant horseweed discovered in SJV, 2005 Photo courtesy of Anil Shrestha, CSUF
New production concepts present opportunities to reassess vineyard design which could affect the ecology of vineyard weeds
OBJECTIVES: Determine whether row orientation of open gable DOV trellis system affects the light environment of weeds growing in the rows. If so, could such differences potentially help manage weeds?
MATERIALS AND METHODS
MATERIALS AND METHODS 3-4 leaf black nightshade (Solanum nigrum) plants were transplanted into 9-l pots
MATERIALS AND METHODS Pots placed beneath the canopy of raisin grapes in rows oriented East-West (E-W) or North-South (N-S) in April
MATERIALS AND METHODS Quantity and quality of light available to weeds measured weekly 3-times a day (9 AM, 12 PM, 3 PM). Photosynthesis and water use of weeds were also measured.
MATERIALS AND METHODS Weeds were harvested 2 months after planting and separated into: roots, stems, leaves and berries Leaf area was measured and each plant part was dried and weighed
SEASONAL SHADOW PATTERNS IN THE VINEYARD East-West North-South 9 AM 12 PM 4 PM PAR 12 PM 0 400 800 1200 1600 PAR 4 PM Date 0 400 800 1200 1600 PAR 9 AM PAR(?molm -2s-1) 0 400 800 1200 1600 NS EW 5/9 5/27 6/24
0 10 20 30 40 50 6.30 7.30 8.30 9.30 10.30 11.30 12.30 14.30 15.30 16.30 17.30 18.30 19.30 Time of day (hrs) Lightlevel(%offullsun) N-S E-W Typical light under the grape canopy zones of the N-S and E-W rows DAILY LIGHT MICROENVIRONMENTS
Row orientation 9 AM 12 PM 4 PM EW 0.26 0.24 0.24 NS 0.87 0.24 0.82 P-value 0.005 0.81 0.009 Red: Far Red ratio
2004 0 200 400 600 800 1000 1200 1400 EW NS 2003 PAR ( mol m-2 sec-1 ) 0 200 400 600 800 1000 1200 1400 Photosynthesis(molCO2 m-2 s-1 ) 0 5 10 15 20 25 Nightshades Need About 30% Full Sun for Optimal Photosynthesis
Clear effects on morphology, but not in shoot mass N-S E-WFull sun
Leaf characteristics of nightshade E-W N-S Larger, thinner leaves in E-W compared to N-S; This might make them more susceptible to herbicides
Nightshade roots Full sun N-S E-W Root mass and R:S ratio declined with shade; full sun > NS > EW
Leaf (33%) Stem (34%) Fruit (18%) Root (14%) Leaf (27%) Stem (31%) Fruit (24%) Root (17%) E-W N-S Row Orientation Affected How the Weeds Used their Resources Weeds in EW were light deficient; they invested more in leaves and stems, and less in fruits and roots than weeds in NS
Seed return of nightshade Row orientation Berries (No.) Seeds/berry (No.) Seeds/plant (No.) EW 155 47 7151 NS 184 51 8976 P-value .07 .004 .03
CONCLUSIONS ? Row direction affected light environment of weeds in this trellis and spacing system ? The growth and productivity of weeds was dependant on their to the light environments; weeds in EW rows produced 20% fewer seeds than weeds in NS rows ? An integrated approach to vineyard design can provide one of the ¡°many little hammers¡± needed to help manage weeds
Acknowledgements Dr. Anil Shrestha Kimberley Cathline Jorge Osorio Aguilar

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Weed suppressive cropping systems

  • 1. Vineyard design and weed suppression: an example with black nightshade (Solanum nigrum) Matthew Fidelibus Extension Specialist Department of Viticulture and Enology University of California, Davis
  • 2. Challenges to Weed Control in San Joaquin Valley (SJV) Vineyards ? Economic: Profit margins are slim and the ¡®cost¡¯ of weeds in mature vineyards is uncertain ? Environmental: ¨C Air and water pollution are major problems in the SJV ¨C Regulation of dust emissions may curtail mechanical controls. ¨C Herbicide use restricted in some SJV vineyards to protect groundwater ? Biological: Many weed species are resistant to common herbicides
  • 3. Weed control a low priority in some raisin vineyards Photo courtesy of Kurt Hembree, UCCE
  • 4. Dust emissions from vehicles, equipment and wind are regulated
  • 5. Herbicide resistant horseweed discovered in SJV, 2005 Photo courtesy of Anil Shrestha, CSUF
  • 6. New production concepts present opportunities to reassess vineyard design which could affect the ecology of vineyard weeds
  • 7. OBJECTIVES: Determine whether row orientation of open gable DOV trellis system affects the light environment of weeds growing in the rows. If so, could such differences potentially help manage weeds?
  • 9. MATERIALS AND METHODS 3-4 leaf black nightshade (Solanum nigrum) plants were transplanted into 9-l pots
  • 10. MATERIALS AND METHODS Pots placed beneath the canopy of raisin grapes in rows oriented East-West (E-W) or North-South (N-S) in April
  • 11. MATERIALS AND METHODS Quantity and quality of light available to weeds measured weekly 3-times a day (9 AM, 12 PM, 3 PM). Photosynthesis and water use of weeds were also measured.
  • 12. MATERIALS AND METHODS Weeds were harvested 2 months after planting and separated into: roots, stems, leaves and berries Leaf area was measured and each plant part was dried and weighed
  • 13. SEASONAL SHADOW PATTERNS IN THE VINEYARD East-West North-South 9 AM 12 PM 4 PM PAR 12 PM 0 400 800 1200 1600 PAR 4 PM Date 0 400 800 1200 1600 PAR 9 AM PAR(?molm -2s-1) 0 400 800 1200 1600 NS EW 5/9 5/27 6/24
  • 14. 0 10 20 30 40 50 6.30 7.30 8.30 9.30 10.30 11.30 12.30 14.30 15.30 16.30 17.30 18.30 19.30 Time of day (hrs) Lightlevel(%offullsun) N-S E-W Typical light under the grape canopy zones of the N-S and E-W rows DAILY LIGHT MICROENVIRONMENTS
  • 15. Row orientation 9 AM 12 PM 4 PM EW 0.26 0.24 0.24 NS 0.87 0.24 0.82 P-value 0.005 0.81 0.009 Red: Far Red ratio
  • 16. 2004 0 200 400 600 800 1000 1200 1400 EW NS 2003 PAR ( mol m-2 sec-1 ) 0 200 400 600 800 1000 1200 1400 Photosynthesis(molCO2 m-2 s-1 ) 0 5 10 15 20 25 Nightshades Need About 30% Full Sun for Optimal Photosynthesis
  • 17. Clear effects on morphology, but not in shoot mass N-S E-WFull sun
  • 18. Leaf characteristics of nightshade E-W N-S Larger, thinner leaves in E-W compared to N-S; This might make them more susceptible to herbicides
  • 19. Nightshade roots Full sun N-S E-W Root mass and R:S ratio declined with shade; full sun > NS > EW
  • 20. Leaf (33%) Stem (34%) Fruit (18%) Root (14%) Leaf (27%) Stem (31%) Fruit (24%) Root (17%) E-W N-S Row Orientation Affected How the Weeds Used their Resources Weeds in EW were light deficient; they invested more in leaves and stems, and less in fruits and roots than weeds in NS
  • 21. Seed return of nightshade Row orientation Berries (No.) Seeds/berry (No.) Seeds/plant (No.) EW 155 47 7151 NS 184 51 8976 P-value .07 .004 .03
  • 22. CONCLUSIONS ? Row direction affected light environment of weeds in this trellis and spacing system ? The growth and productivity of weeds was dependant on their to the light environments; weeds in EW rows produced 20% fewer seeds than weeds in NS rows ? An integrated approach to vineyard design can provide one of the ¡°many little hammers¡± needed to help manage weeds
  • 23. Acknowledgements Dr. Anil Shrestha Kimberley Cathline Jorge Osorio Aguilar

Editor's Notes

  • #2: Thank Anil Shrestha
  • #3: Some herbicide have high VOCs
  • #14: Dark soil from water may look like shadow, but soil below N-S rows was sunlit in the morning and afternoon whereas it was constantly shaded in EW
  • #16: Lower R:FR could promote shade avoidance strategies. Weed canopy zone (WCZ) in EW rows have lower R:FR in morning and afternoon.