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Spatial and Population Dynamics of Patches of Wild-oats

Spatial and Population Dynamics of Patches of Wild-oats. Nicola Perry and Peter Lutman IACR-Rothamsted. Background:. Wild-oats:. Important grass weed Patchy distribution Patch stability unknown. Experiment details. Patch size 3x3 m Two sowing densities: 10 plants/m 2 and 50 plants/m 2

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Spatial and Population Dynamics of Patches of Wild-oats

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  1. Spatial and Population Dynamics of Patches of Wild-oats Nicola Perry and Peter Lutman IACR-Rothamsted Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  2. Background: Wild-oats: • Important grass weed • Patchy distribution • Patch stability unknown Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  3. Experiment details • Patch size 3x3 m • Two sowing densities: • 10 plants/m2 and 50 plants/m2 • Ploughing, cultivations and combining in same direction each year • +/- wild-oat herbicide in 2000 Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  4. Experiment design 12m 3m HD SHD LD SHD 3m 30m HD SLD LD SLD HD = high density; LD = low density; S = sprayed N arrows indicate cultivation & combining direction Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  5. Monitoring • Panicle distribution • Seed movement • Patch shape • Location of outliers Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  6. Panicle and seed distribution 1999 Panicles / m2 Seeds / m2 Direction of cultivation & combining Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  7. Panicle and seed distribution Sprayed Treatments 2000 Panicles / m2 Seeds / m2 Direction of cultivation & combining Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  8. Seed distribution after harvestSprayed v Unsprayed 2000 Total no. seeds/m2 Sprayed: 17,860 Unsprayed: 139,410 Direction of cultivation & combining Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  9. Low Density Sprayed Patch harvesting & cultivation 1998 (9 m2) 1999 (20.3 m2) 2000 (20.6 m2) m Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  10. High Density Unsprayed Patch harvesting & cultivation 1998 (9 m2) 1999 (29.5 m2) 2000 (41.0 m2) m Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  11. 1999 Patch outline Outliers Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  12. 2000 Patch outline S Outliers S S S Sprayed plots S Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  13. Conclusions • Majority of seeds move 1-2 m • movement due to cultivations and plants leaning in wind • Isolated plants occur up to 30 m away • movement by combine • may lead to future infestations / new patches Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  14. Conclusions • Wild-oats need frequent re-mapping • Patches not stable and new patches may form from isolated plants • Presence of outliers make decisions on patch spraying complicated Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  15. Limitations of manually mapping weed patches Nicola Perry and Peter Lutman IACR-Rothamsted Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  16. Methods of manually mapping weed patches • Visual detection (human) • mapping on a grid • ATV, tractor/sprayer, combine • walking around patches Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  17. Weed attributes which can be recorded • Presence / absence • Approximate levels (high / low) • Weed numbers • Weed vigour / ground cover Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  18. Weed attributes which can be recorded from a vehicle or using quadrats Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  19. Timing of visual assessments Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  20. Activities on Warren Field(winter wheat) Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  21. Warren Field black-grass comparison of mapping methods Quadrat threshold 20 plants/m2 (Dec 99) ATV (Jan 00) Correlation : 0.82 Black-grass No Black-grass Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  22. Warren Field black-grass comparison of mapping methods Quadrat threshold 5 plants/m2 (Dec 99) ATV (Jan 00) Correlation : 0.60 Black-grass No Black-grass Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  23. Warren Field black-grass comparison of mapping methods Quadrat threshold 20 plants/m2 (Dec 99) Tractor (June 00) Correlation : 0.37 Black-grass No Black-grass Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  24. Warren Field black-grass comparison of mapping methods Quadrat threshold 2 plants/m2 (Dec 99) Tractor (June 00) Correlation : 0.84 Black-grass No Black-grass Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  25. Warren Field wild-oats comparison of mapping methods Quadrat threshold 2 plants/m2 (Dec 99) ATV (Jan 00) Correlation : 0.74 Wild-oats No Wild-oats Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  26. Warren Field wild-oats comparison of mapping methods Quadrat threshold 2 plants/m2 (Dec 99) Tractor (June 00) Correlation : 0.58 Wild-oats No Wild-oats Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  27. Broad Mead black-grass comparison of mapping methods Quadrat threshold 5 plants/m2 (Dec 99) ATV (Jan 00) Correlation : 0.70 Black-grass No Black-grass Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  28. Black-grass distribution in Cashmore Field Mapped from ATV Nov 99 Mapped on foot May 00 Mapped from combine July 00 Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  29. Conclusions • Limitations to manually mapping weeds • Discrete quadrat sampling too time consuming for mapping on a whole-field scale • Continuous visual detection from a vehicle is less accurate, & may be restricted to tramlines, but is quicker Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

  30. Conclusions • Need to make more progress with optimum visual detection in absence of automated detection Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk

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