Department of Agriculture and EcologyWeed flora changes in responseto weed control over thelast 100 yearsAssociate Profess...
Department of Agriculture and Ecology                                    Weed surveys in Denmark 1911-15                  ...
Department of Agriculture and Ecology            Average number of species among 67 weed species                   surveye...
Department of Agriculture and Ecology    Changes of importance for the weed flora on the                 period 1987 to 20...
Department of Agriculture and Ecology    Average number of species (±SD) recorded in a single                Raunkiær circ...
Department of Agriculture and Ecology           Changes in frequency of Poa annuaFrequency %9080                          ...
Department of Agriculture and Ecology       Reasons for weed flora changes          during the last 100 year•   Crop rotat...
Department of Agriculture and Ecology           Cluster analysis of crops based on frequency     of occurrence of all spec...
Department of Agriculture and Ecology              Area of 10 crops as a fraction of the total arable                     ...
Department of Agriculture and Ecology                       Crop rotation  Is an important control methods to minimise the...
Department of Agriculture and Ecology    New crops may create new weed problems!Prague, 14 June 2011Dias 12
Department of Agriculture and Ecology               Echinochlora sp. and Setaria viridis in maizePrague, 14 June 2011Dias 13
Department of Agriculture and EcologyRed fescue (Festuca rubra)   Vulpia bromoides                                From:flo...
Department of Agriculture and Ecology                               Nitrogen and fertilisationAverage nitrogen fertilizer ...
Department of Agriculture and EcologyNitrogen fertilisers favour nitrophilous speciesElytrigia repensPoa annuaChenopodium ...
Department of Agriculture and Ecology          Use of lime has tripled since 1950Negative effect on calcifuge weed species...
Department of Agriculture and Ecology                       The effect of herbicidesPrague, 14 June 2011Dias 18
Changes in the dry weight production of                       Galium aparine after spraying                        with MC...
Department of Agriculture and Ecology                                       Dose response curve for a herbicideUncertainty...
Department of Agriculture and Ecology                       Changes in frequency of Frequency %              Elytrigia rep...
Department of Agriculture and Ecology                       Changes in frequency                        of Cirsium arvense...
Department of Agriculture and Ecology                 Number of resistent biotypes                                        ...
Department of Agriculture and Ecology                       Number of resistant biotypesPrague, 14 June 2011Dias 24
Department of Agriculture and Ecology                       Number of Resistant BiotypesPrague, 14 June 2011Dias 25
Department of Agriculture and EcologyPrague, 14 June 2011Dias 26
Department of Agriculture and Ecology                                          Seed cleaning             Improved techniqu...
Department of Agriculture and Ecology Mechanisation and changes in cultivation methodsEquisitum arvense Tussilago farfara ...
Department of Agriculture and Ecology          Combine harvester favoured seed           dispersal of certain therophytesS...
Department of Agriculture and EcologyMechanisation and changes in cultivation methods      Heavy machinery favour some spe...
The germination of seeds of various weeds in    relation to partial pressure of oxygenGermination %  100 Alopecurus myosur...
Department of Agriculture and Ecology    Prohibition on straw-burning and reduced  stubble cultivation could partly be res...
Department of Agriculture and EcologyDifferent soil cultivation methods impose different weed flora   Prague, 14 June 2011...
Department of Agriculture and Ecology  Ordinary                Reducedsoil cultivation       soil cultivationPrague, 14 Ju...
Department of Agriculture and EcologyConclusion and outlook•    Several factors have operated in concert to influence     ...
Department of Agriculture and Ecology             Thank you for your attention!Prague, 14 June 2011Dias 36
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ChristianAndreasen_Prague_Jun11

  1. 1. Department of Agriculture and EcologyWeed flora changes in responseto weed control over thelast 100 yearsAssociate Professor Christian AndreasenDepartment of Agriculture and EcologyCrop SciencePrague, 14 June 2011Dias 1
  2. 2. Department of Agriculture and Ecology Weed surveys in Denmark 1911-15 1940-45 1960-70 1987-89 2001-04 l l l l l l l l l l l 1910 1930 1950 1970 1990 2010Crops: 2 2 19 9 11Fields:64 50 466 357 407 Prague, 14 June 2011 Dias 2
  3. 3. Department of Agriculture and Ecology Average number of species among 67 weed species surveyed in a single circle of 0.1 m28 1967-707 1987-896543210 Spring barley Spring rape Winter rye Winter wheat Grass leysPrague, 14 June 2011Dias 3
  4. 4. Department of Agriculture and Ecology Changes of importance for the weed flora on the period 1987 to 2000• Pesticide action plans• The amount of active ingredient has been reduced 50% and the treatment index has been reduced 1/4• New herbicides have been introduced• Set aside directives• Organic farming make up about 6%• The mean farm size has increased from 32.2 to 44.7ha• Change in use of cropping area Prague, 14 June 2011 Dias 4
  5. 5. Department of Agriculture and Ecology Average number of species (±SD) recorded in a single Raunkiær circle of 0.1 m2Average number of weed species 12 1967-70 10 1987-89 2001-04 8 6 4 2 0 Spring Spring rape Winter rye Winter Grass ley Peas Fodder Sugar beets Winter barley wheat beets barley Prague, 14 June 2011 Dias 6
  6. 6. Department of Agriculture and Ecology Changes in frequency of Poa annuaFrequency %9080 1987-8970 2001-046050403020100 Sugar beets Fodder S. barley S. rape Peas w. barley W. wheat W. rye Grass leys beets Prague, 14 June 2011 Dias 7
  7. 7. Department of Agriculture and Ecology Reasons for weed flora changes during the last 100 year• Crop rotation• Fertilisation• Drainage• Herbicides• Seed cleaning• Mechanisation and changes in cultivation methods• LegislationPrague, 14 June 2011Dias 8
  8. 8. Department of Agriculture and Ecology Cluster analysis of crops based on frequency of occurrence of all species in a Danish survey (2001-2004) A B C DPrague, 14 June 2011Dias 9
  9. 9. Department of Agriculture and Ecology Area of 10 crops as a fraction of the total arable area in DenmarkPercentage of total arable land 45 40 1967-70 1987-89 35 2001-04 30 25 20 15 10 5 0 Winter Spring Winter Winter Spring Maize Grass Sugar Fodder Winter rye barley barley rape rape leys beets beets wheat (From Andreasen & Stryhn, 2005) Prague, 14 June 2011 Dias 10
  10. 10. Department of Agriculture and Ecology Crop rotation Is an important control methods to minimise the occurrence of weeds, which pose particularly problems in specific crops Apera spica-venti in cerealsPrague, 14 June 2011Dias 11
  11. 11. Department of Agriculture and Ecology New crops may create new weed problems!Prague, 14 June 2011Dias 12
  12. 12. Department of Agriculture and Ecology Echinochlora sp. and Setaria viridis in maizePrague, 14 June 2011Dias 13
  13. 13. Department of Agriculture and EcologyRed fescue (Festuca rubra) Vulpia bromoides From:florabase.calm.wa.gov.au Prague, 14 June 2011 Dias 14
  14. 14. Department of Agriculture and Ecology Nitrogen and fertilisationAverage nitrogen fertilizer (kg/ha) used on arable land200180160140120100 80 60 40 N fertiliser (kg/ha) 20 0 1950 1960 1970 1975 1979 (from Haas & Streibig, 1982) Commercial Dung and slugde N-fixation From air Fertilizer slurry manure Prague, 14 June 2011 (From: http://dmu.dk) Dias 15
  15. 15. Department of Agriculture and EcologyNitrogen fertilisers favour nitrophilous speciesElytrigia repensPoa annuaChenopodium albumStellaria mediaEnhance the shading ability of cropsShade tolerant speciesPoa annuaStellaria mediaViola arvenseSpecies able to elongate into more favourable light conditionFallopia convolvulusGalium aparinePrague, 14 June 2011Dias 16
  16. 16. Department of Agriculture and Ecology Use of lime has tripled since 1950Negative effect on calcifuge weed species:Rumex acetosellaScleranthus annuusSpergula arvensisFavour weed species like:Veronica persicaAnagallis arvensisLamium purpureumPrague, 14 June 2011Dias 17
  17. 17. Department of Agriculture and Ecology The effect of herbicidesPrague, 14 June 2011Dias 18
  18. 18. Changes in the dry weight production of Galium aparine after spraying with MCPA and Mecoprop 200% of untreated 150 MCPA 100 Mecoprop Mechlorprop 50 0 Control 0.5 l /ha 1.0 l/ha 2.0 l/ha 1,0l (Petersen, 1960) (From Petersen, 1960)
  19. 19. Department of Agriculture and Ecology Dose response curve for a herbicideUncertainty Uncertainty 90% effect level 70% effect level Per cent effect DosePrague, 14 June 2011Dias 20
  20. 20. Department of Agriculture and Ecology Changes in frequency of Frequency % Elytrigia repens 18 16 1987-89 2001-04 14 12 10 8 6 4 2 0 pe y er ts W ley as S. y G rye s at le rle et dd ee he Pe ra ar be ss ba .Fo r b W .w .b ra ga S. WPrague, 14 June 2011 SuDias 21
  21. 21. Department of Agriculture and Ecology Changes in frequency of Cirsium arvense Frequency % 6 1987-89 5 2001-04 4 3 2 1 0 ys S. ets .b s er ts S. y W ye ra pe pe W t .w y a W ea rle W rle dd e e he le .r G ra ra be P ba a Fo r b ss . ga SuPrague, 14 June 2011Dias 22
  22. 22. Department of Agriculture and Ecology Number of resistent biotypes Senecio vulgarisPrague, 14 June 2011Dias 23
  23. 23. Department of Agriculture and Ecology Number of resistant biotypesPrague, 14 June 2011Dias 24
  24. 24. Department of Agriculture and Ecology Number of Resistant BiotypesPrague, 14 June 2011Dias 25
  25. 25. Department of Agriculture and EcologyPrague, 14 June 2011Dias 26
  26. 26. Department of Agriculture and Ecology Seed cleaning Improved techniques for crop seed cleaning have almost eradicated some species that were widespread before the Second World WarSteve Hurst @ USDA-NRCS PLANTS Database Lolium temulentum Agrostemma githago Prague, 14 June 2011 Dias 27
  27. 27. Department of Agriculture and Ecology Mechanisation and changes in cultivation methodsEquisitum arvense Tussilago farfara Sonchus arvensis Elytrigia repens Prague, 14 June 2011 Dias 28
  28. 28. Department of Agriculture and Ecology Combine harvester favoured seed dispersal of certain therophytesSome species shed seed later than the time at which reaping previous has been carried out but earlier than the present combine harvest:Capsella bursa-pastorisChenopodium albumMatricaria discoideaPolygonum aviculareStellaria mediaTripleurospermum inodorumPrague, 14 June 2011Dias 29
  29. 29. Department of Agriculture and EcologyMechanisation and changes in cultivation methods Heavy machinery favour some species: Chamomilla recutita Chamomilla suaveolens Plantago major Poa annua Polygonum aviculare Tripleurospermum inodorum Prague, 14 June 2011 Dias 30
  30. 30. The germination of seeds of various weeds in relation to partial pressure of oxygenGermination % 100 Alopecurus myosuroides 80 Avena fatua 60 Matricaria chamomilla Poa annua 40 Stellaria media 20 Chenopodium album 0 2 4 6 8 10 12 14 16 18 20 Oxygen % Oxygen (%) (Müllerstedt, 1953)
  31. 31. Department of Agriculture and Ecology Prohibition on straw-burning and reduced stubble cultivation could partly be responsible for an increase in grass weedsPrague, 14 June 2011Dias 32
  32. 32. Department of Agriculture and EcologyDifferent soil cultivation methods impose different weed flora Prague, 14 June 2011 Dias 33
  33. 33. Department of Agriculture and Ecology Ordinary Reducedsoil cultivation soil cultivationPrague, 14 June 2011Dias 34
  34. 34. Department of Agriculture and EcologyConclusion and outlook• Several factors have operated in concert to influence changes in weed abundance• Crop rotation, fertilization, mechanisation, management strategy and use of herbicides• The common agricultural policy influence the farmers choice of crop and with it the weed flora• Political initiatives to reduce side effects of pesticides and fertiliser will affect the weed floraPrague, 14 June 2011Dias 35
  35. 35. Department of Agriculture and Ecology Thank you for your attention!Prague, 14 June 2011Dias 36

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