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

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

3. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Experiment details Patch size 3x3 m Two sowing densities: –10 plants/m 2 and 50 plants/m 2 Ploughing, cultivations and combining in same direction each year +/- wild-oat herbicide in 2000

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

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

7. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Panicle and seed distribution 1999 Panicles / m 2 Seeds / m 2 Direction of cultivation & combining

8. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Panicle and seed distribution Sprayed Treatments 2000 Panicles / m 2 Seeds / m 2 Direction of cultivation & combining

9. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Seed distribution after harvest Sprayed v Unsprayed 2000 Direction of cultivation & combining Total no. seeds/m 2 Sprayed: 17,860 Unsprayed: 139,410

10. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Low Density Sprayed Patch 1998 (9 m 2 ) 1999 (20.3 m 2 ) 2000 (20.6 m 2 ) m harvesting & cultivation

11. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk m 1998 (9 m 2 ) 1999 (29.5 m 2 ) 2000 (41.0 m 2 ) High Density Unsprayed Patch harvesting & cultivation

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

13. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk 2000 Patch outline Outliers S S S S SSprayed plots

14. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk 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

15. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk 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

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

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

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

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

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

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

25. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Warren Field black-grass comparison of mapping methods Correlation : 0.82 Quadrat threshold 20 plants/m 2 (Dec 99) Black-grass No Black-grass ATV (Jan 00)

26. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Warren Field black-grass comparison of mapping methods Correlation : 0.60 Quadrat threshold 5 plants/m 2 (Dec 99) Black-grass No Black-grass ATV (Jan 00)

27. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Warren Field black-grass comparison of mapping methods Correlation : 0.37 Quadrat threshold 20 plants/m 2 (Dec 99) Black-grass No Black-grass Tractor (June 00)

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

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

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

31. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk Broad Mead black-grass comparison of mapping methods ATV (Jan 00) Correlation : 0.70 Quadrat threshold 5 plants/m 2 (Dec 99) Black-grass No Black-grass

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

33. Nicola.Perry@bbsrc.ac.uk Peter.Lutman@bbsrc.ac.uk 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

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