Evaluation of changes in weed flora in arable fields of Nordic countries - based on Danish long-term surveys

Weed Research

Volumn 51, Issue 3, 2011, Pages 214-226

  Andreasen, C ^a   Streibig, J C ^a  

^a UNIVERSITY OF COPENHAGEN   (Denmark)

Author keywords

Agroecology; Biodiversity; Intensive farming; National survey; Weed composition; Weed control; Weed management

Indexed keywords

ABUNDANCE; AGRICULTURAL PRODUCTION; AGROECOLOGY; AGRONOMY; ARABLE LAND; COMMON AGRICULTURAL POLICY; CROP IMPROVEMENT; ENVIRONMENTAL PROTECTION; EUROPEAN UNION; FERTILIZER APPLICATION; FIELD SURVEY; GRASS; HERBICIDE; INTENSIVE AGRICULTURE; SPECIES DIVERSITY; WEED CONTROL; YIELD RESPONSE;

SCANDINAVIA;

ZEA MAYS;

EID: 79955539703     PISSN: 00431737     EISSN: 13653180     Source Type: Journal    
DOI: 10.1111/j.1365-3180.2010.00836.x     Document Type: Article

References (127)

1. Aamisepp A, Stecko V & ÅBerg E (1967) Ogräs frö spridning vid bindarskörd och skördetröskning. Landbrukshögsk Medd. Serie A 81, 31.
2. Albrecht H (1995) Changes in arable weed flora of Germany during the last five decades. In: Proceedings of the 9th EWRS Symposium, European Weed Research Society, Budapest, Hungary, 41-48.
3. Allen HP, Brian RC, Downes JE, Mees GC & Springett RH (1978) Selective herbicides. In: Jealott's Hill Fifty Years of Agricultural Research, 1928-1978 (ed. FC Peacock), 35-41. The Kynoch Press, Birmingham, UK.
4. Andersen JM, Boutrup S, Svendsen LM, Bøgestrand J et al. (2005) Aquatic environment 2004. State and trends - technical summary. NIRI technical Report no 561, 2005. National Environmental Research Institute. Ministry of the Environment, Denmark.
5. Andersson TN & Milberg P (1998) Weed flora and the relative importance of site, crop, crop rotation, and nitrogen. Weed Science 46, 30-38.
6. Andreasen C (1990) The Occurrence of Weed Species in Danish Arable Fields. PhD thesis, Department of Agricultural Sciences, The Royal Veterinary and Agricultural University, Copenhagen, Denmark.
7. Andreasen C & Skovgaard IM (2009) Crop and soil factors of importance for the distribution of plant species on arable fields. Agriculture, Ecosystems and Environment 133, 61-67.
8. Andreasen C & Streibig JC (2001) Reduced tillage and weed management in Scandinavia. Conservation agriculture, a worldwide challenge. I World Congress on Conservation Agriculture, Madrid, 1-5 October, 2001. Food and Agriculture Organisation of United Nations (FAO) and the European Conservation Agriculture Federation (ECAF). Spain, 443-446.
9. Andreasen C & Stryhn H (2008) Increasing weed flora in Danish arable fields and its importance for biodiversity. Weed Research 48, 1-9.
10. Andreasen C, Jensen JE & Streibig JC (1991a) Soil properties and plant nutrients affecting the occurrence of Poa annua, Stellaria media and Viola arvensis on arable land. In: Brighton Crop Protection Conference - Weeds. British Crop Protection Council, Farnham, UK, 395-402.
11. Andreasen C, Streibig JC & Haas H (1991b) Soil properties affecting the distribution of 37 weed species in Danish fields. Weed Research 31, 181-187.
12. Andreasen C, Jensen JE & Haas H (1992) Grøn Skærmaks (Setária víridis) og Hanespore (Echinóchloa sp.): Nye græsukrudtsarter i Danmark (Setária viridis and Echinochloa: New grass weed species in Denmark). In: 9th Danish Plant Protection Conference/Weeds. Statens Planteavlsforsøg, beretn. S 2178-1992, 49-60.
13. Andreasen C, Jensen JE, Madsen KH, Poulsen GS & Streibig JC (1995) Herbicide resistance in weeds and crops in Denmark. In: Proceedings of the International Symposium on Weed and Crop Resistance to Herbicides. Cordoba, Spain, 3-6 April 1995. Universidad de Cordoba, Serie Actas 24, 175-177.
14. Andreasen C, Stryhn H & Streibig JC (1996) Decline of the flora in Danish arable fields. Journal of Applied Ecology 33, 619-626.
15. Andreasen C, Litz A-S & Streibig JC (2006) Growth response of six weed species and spring barley (Hordeum vulgare) to increasing levels of nitrogen and phosphorus. Weed Research 46, 503-512.
16. Anon (1971) Landbrugsstatistik 1970 herunder gartneri og skovbrug. Danmarks Statistik, Copenhagen, Denmark.
17. Anon (1990) Landbrugsstatistik 1989. Danmarks Statistik, Copenhagen, Denmark, 124.
18. Anon (1991) Bekendtgørelse om forbud mod markafbrænding af halm m.v. Bekendtgørelse nr. 545 af 12. juli 1991. Danish Ministry of Environment.
19. Anon (2001) Landbrug 2004, Statistik om landbrug, gartneri og skovbrug. Danmarks Statistik, Copenhagen, Denmark. 94.
20. Anon (2004) In: Vejledning i planteværn 2004 (eds PH Petersen, PK Jensen, LN Jørgensen, GC Nielsen, SF Nielsen & K Paaske), 155. Dansk Landbrugsrådgivning, Landscentret, Århus, Denmark.
21. Anon (2005) Landbrug 2004, Statistik om landbrug, gartneri og skovbrug. Danmarks Statistik, Copenhagen, Denmark. 80.
22. Anon (2006) Danmarks Statistik - statistikbanken.dk. (last accessed 8 November 2010).
23. Anon (2008) Danmarks Statistik (last accessed 8 November 2010).
24. Anon (2009) European Parliament legislative resolution of 13 January 2009 on the Council common position for adopting a directive of the European Parliament and of the Council establishing a framework for Community action to achieve a sustainable use of pesticides (6124/2008 - C6-0323/2008 - 2006/0132(COD)) (last accessed 8 November 2010).
25. Bachthaler G (1982) The occurrence of weed species with low constancy and coverage levels at arable land locations in Bavaria during the investigation periods 1950 to 1960 and 1961-1980. Angewandte Botanik 56, 219-236.
26. Baessler C & Klotz S (2006) Effects of changes in agricultural land-use on landscape structure and arable weed vegetation over the last 50years. Agriculture, Ecosystems and Environment 115, 43-50.
27. Baylis AB (2000) Why glyphosate is a global herbicide: strengths, weaknesses and prospects. Pest Management Science 56, 299-308.
28. Beckie HJ, Harker KN, Hall LM et al. (2006) A decade of herbicide-resistant crops in Canada. Canadian Journal of Plant Science 86, 1243-1264.
29. Benton TG, Vickery JA & Wilson JD (2003) Farmland biodiversity: is habitat heterogeneity the key? Trends in Ecology and Evolution 18, 182-188.
30. Binimelis R, Pengue W & Monterroso L (2009) "Transgenic treadmill": responses to the emergence and spread of glyphosate-resistant johnsongrass in Argentina. Geoforum 40, 623-633.
31. Blacklow M & Andreasen C (1993) The Biology of Lolium: will L. temulentum be similar to L. rigidum and threaten crop rotation in Western Australia? In: Proceedings of the 14th Asian-Pacific Weed Science Society/10th Australia Weed Science Society Conference. Weed management - towards tomorrow. Brisbane, Australia. 358-362.
32. Blackman GE (1952) Studies of the principles of phytotoxicity I. The assessment of relative toxicity. Journal of Experimental Botany 3, 1-2.
33. Bohan DA, Boffey WHC, Brooks DR, Clark SJ et al. (2005) Effects on weed and invertebrate abundance and diversity of herbicide management in genetically modified herbicide-tolerant winter-sown oilseed rape. Philosophical Transactions of the Royal Society B 272, 463-474.
34. Bohren C, Delabays N & Rometsch S (2008) Invasive plants: agricultural aspects. Agrarforschung 15, 314-319.
35. Cavan G, Cussans J & Moss SR (2000) Modelling different cultivation and herbicide strategies for their effect on herbicide resistance in Alopecurus myosuroides. Weed Research 40, 561-568.
36. Chandler S & Dunwell JM (2008) Gene flow, risk assessment and the environmental release of transgenic plants. Critical Reviews in Plant Sciences 27, 25-49.
37. Christensen S, Søgaaard HT, Kudsk P, Nørremark M et al. (2009) Site-specific weed control technologies. Weed Research 49, 233-241.
38. Chtioui Y, Bertrand D, Dattée Y & Devaux MF (1999) Identification of seeds by colour imaging: comparison of discriminant analysis and artificial neural network. Journal of the Science of Food and Agriculture 71, 433-441.
39. Cimalova S & Lososova Z (2009) Arable weed vegetation of the northeastern part of the Czech Republic: effects of environmental factors on species composition. Plant Ecology 203, 45-57.
40. Ciuberkis S, Bernotas S & Raudonius S (2006) Long-term manuring effect on weed flora in acid and limed soils. Acta Agriculturae Scandinavica, Section B - Plant Soil Science 56, 96-100.
41. Clarke JH, Orlando D & Melander B (1995) Comparison of the effect of weed control strategies for rotational set-aside in United Kingdom, Denmark and France. In: Brighton Crop Protection Conference-Weeds. The British Crop Protection Council, Farnham, UK, 329-338.
42. Cobb A (1992) Herbicides and Plant Physiology. Chapman & Hall, London, UK, 131-140.
43. Cussans GW, Moss SR, Pollard F & Wilson BJ (1979) Studies of the effect of tillage on annual weed populations. The influence of different factors on the development and control of weeds. In: Proceedings of European Weed Research Society Symposium. Mainz, Germany, 115-122.
44. Dale MRT, Thomas AG & John EA (1992) Environmental factors including management practices as correlates of weed community composition in spring seeded crops. Canadian Journal of Botany 70, 1931-1939.
45. Devine MC, Duke SO & Fedtke C (1993) Physiology of herbicide actions. Prentice Hall, Englewood Cliffs, NJ, 225-243.
46. Duke SO (2005) Taking stock of herbicide-resistant crops ten years after introduction. Pesticide Management Science 61, 211-218.
47. Duke SO & Powles SB (2008) Glyphosate: a once-in-a-century herbicide. Pest Management Science 64, 319-325.
48. Erviö L-R & Salonen J (1987) Changes in the weed population of spring cereals in Finland. Annals of Agriculturae Fenniae 26, 201-226.
49. Erviö R, Hyvarinen S, Erviö L-R & Salonen J (1994) Soil properties affecting weed distributions in spring cereal and vegetable fields. Agricultural Science in Finland 3, 497-504.
50. Esser HO, Dupuis G, Ebert E, Vogel C & Marco GJ (1975) S-trazines. In: Herbicides Chemistry, Degradation and Mode of Action (eds PC Kerney & DD Kaufman), 129-208. Marcel Dekker, New York, NY, USA.
51. Fedtke C (1982) Biochemistry and Physiology of Herbicide Action. Springer-Verlag, Berlin, Germany, 159-176.
52. Fogelfors H (1973) Några ogräsarters utveckling under skida ljusforhållanden och koncurrensförmåga i kornbestånd. Dissertation, Swedish University of Agricultural Sciences, Department of Plant Husbandry, Uppsala.
53. Freyssinet G (2003) Herbicide-resistant transgenic crops - a benefit for agriculture. Phytoparasitica 31, 105-108.
54. Fried G, Petit S, Dessaint F & Reboud X (2009) Arable weed decline in Northern France: crop edges as refugia for weed conservation? Biological Conservation 142, 238-243.
55. Froud-Williams J, Drennan DSH & Chancellor RJ (1983) Influence of Cultivation regime on weed flora of arable cropping systems. Journal of Applied Ecology 20, 187-197.
56. Fumanal B, Girod C, Fried G, Bretagnolle F & Chauvel B (2008) Can the large ecological amplitude of Ambrosia artemisiifolia explain its invasive success in France? Weed Research 48, 349-359.
57. Geissbühler H, Martin H & Voss G (1975) The substituted ureas. In: Herbicides Chemistry, Degradation and Mode of Action (eds PC Kerney & DD Kaufman), 209-291. Marcel Dekker, New York, NY, USA.
58. Gianessi LP (2008) Economic impacts of glyphosate-resistant crops. Pest Management Science 64, 346-352.
59. Grossman K & Scheltrup F (1995) On the mode of action of the new, selective herbicides Quinmerac. In: Brighton Crop Protection Conference - Weeds 1995. The British Crop Protection Council, Farnham, UK, 1, 393-398.
60. Gurian-Sherman D (2006) Contaminating the Wild? Gene Flow from Experimental Field Trials of Genetically Engineered Crops to Related Wild Plants. Center for Food Safety, Washington, DC, USA.
61. Haas H & Streibig JC (1982) Changing patterns of weed distribution as a result of herbicide use and other agronomic factors. In: Herbicide Resistance in Plants (eds HM LeBaron & J Gressel), 57-79. John Wiley & Sons, New York, NY, USA.
62. Håkansson I, Voorhees WB & Riley H (1988) Vehicle and wheel factors influencing soil compaction and crop response in different traffic regimes. Soil Tillage Research 11, 239-282.
63. Hald AB (1999) The impact of changing the season in which cereals are sown on the diversity of the weed flora in rotational fields in Denmark. Journal of Applied Ecology 36, 24-32.
64. Hald AB & Petersen PM (1992) Soil and vegetation in two Danish fens following changes in water regime. Nordic Journal of Botany 12, 707-732.
65. Hallgren E (1996) Do the weed flora and effect of a herbicide change with time? Proceedings of the Second International Weed Control Congress, Copenhagen, Denmark. Department of Weed Control and Pesticide Ecology, Flakkebjerg, Slagelse, Denmark, 1355-1368.
66. Hallqvist H (2002) Resistent renkavle finns även i Sverige. Ogräsbrev 2002-09-09. Jordbruksverket, Växtskyddscentralen Alnarp.
67. Hansen P, Rasmussen I, Holst N & Andreasen C (2007) Tolerance of four spring barley (Hordeum vulgare L.) varieties to weed harrowing. Weed Research 47, 241-251.
68. Hansson M & Fogelfors H (1998) Management of permanent set-aside on arable land in Sweden. Journal of Applied Ecology 35, 758-771.
69. Heap I (2010) The International Survey of Herbicide Resistant Weeds. Online Available on (last accessed November 8, 2010).
70. Heard MS, Hawes C, Champion GT, Clark SJ et al. (2003) Weeds in fields with contrasting conventional and genetically modified herbicide-tolerant crops 1. Effects on abundance and diversity. Philosophical Transactions of the Royal Society B 358, 1819-1832.
71. Hilbig W & Otto HW (1988) Veränderungen der Ackerunkrautflora der Oberlausitz in Zeitraum von 1965 bis 1985. Abhandlungen und berichte des Naturkundemuseum Görlitz 61, 1-68.
72. Hill JE (1995) Herbicide tolerant crops - environmentalists concerns and regulatory responses. In: Proceedings BCPC Brighton Crop Protection Conference -Weeds, 1027-1034. BCPC, Farnham, UK.
73. Hyvönen T, Ketoja E & Salonen J (2003) Changes in the abundance of weeds in spring cereal fields in Finland. Weed Research 43, 348-356.
74. Hyvönen T, Holopainen J & Tiainen J (2005) Detecting the spatial component of variation in the weed community at the farm scale with variation partitioning by canonical correspondence analysis. Weed Research 45, 48-56.
75. Jensen HA (1969) Content of buried seeds in arable soil in Denmark and its relation to the weed population. Dansk Botanisk Arkiv 27, 1.
76. Jensen PK (1991) Weed size hierarchies in Denmark. Weed Research 31, 1-7.
77. Jensen JE & Andreasen C (1993) The Poa species: problem and management in Danish arable fields. In: Brighton Crop Protection Conference-Weeds. Farnham, UK, 89-94.
78. Kaloumenos NS & Eleftherohorinos IG (2002) Corn poppy (Papaver rhoeas) resistance to ALS-inhibiting herbicides and its impact on growth rate. Weed Science 56, 789-796.
79. Keeley PE & Thullen RJ (1989) Influence of planting date on the growth of barnyard grass (Echinóchloa crus-galli). Weed Science 37, 557-561.
80. Kudsk P, Mathiassen SK & Cotterman JC (1995) Sulfonylurea resistance in Stellaria media [L.] Vill. Weed Research 35, 19-24.
81. Lapinsh D, Korolova J & Berzinsh A (2008) Crop rotation influence on the weed incidence in cereals. Zemdirbyste-Agriculture 95, 433-439.
82. Lassen P (1988) Om gullört, Amsinckia, i Norden. Svensk botanisk tidskrift 82, 143-150.
83. Loos MA (1975) Phenoxyalkanoic acids. In: Herbicides Chemistry, Degradation and Mode of Action (eds PC Kerney & DD Kaufman), 1-128. Marcel Dekker, New York, USA.
84. Lososova Z, Chytry M, Cimalova S, Kropac Z et al. (2004) Weed vegetation of arable land in central Europe: gradients in diversity and species composition. Journal of Vegetation Science 15, 415-422.
85. Martin TJ (1987) Broad versus narrow-spectrum herbicides and future of mixtures. Pesticide Science 20, 289-299.
86. Melander B, Holst N, Jensen PK, Hansen EM & Olsen JE (2008) Apera spica-venti population dynamics and impact on crop yield as affected by tillage, crop rotation, location and herbicide programmes. Weed Research 48, 48-57.
87. Mikkelsen VM & Laursen F (1966) Markukrudt i Danmark omkring 1960. Botanisk Tidsskrift 62, 1.
88. Milberg P & Andersson L (2006) Evaluating the potential northward spread of two grass weeds in Sweden. Acta Agriculturae Scandinavica, Section B - Plant Soil Science 56, 91-95.
89. Milberg P & Hallgren E (2004) Yield loss due to weeds in cereals and its large-scale variability in Sweden. Field Crops Research 86, 199-209.
90. Morris NL, Miller PCH, Orson JH & Froud-Williams RJ (2010) The adoption of non-inversion tillage systems in the United Kingdom and the agronomic impact on soil, crops and the environment - a review. Soil & Tillage Research 108, 1-15.
91. Moss SR & Cussans GW (1991) The development of herbicide resistant population of Alopecurus myosuroides (black-grass) in England. In: Herbicide Resistant in Weeds and Crops (eds C Caseley, GW Cussans & RK Atkin), 445-465. Butterworth-Heneman, Oxford, UK.
92. Mullverstedt R (1963) Untersuchungen über die Keimung von Unkrautsamen in Abhängigkeit von Sauerstoffpartialdrück. Weed Research 10, 26-29.
93. Netland J (1996) Weed species and frequency of simazine-resistant populations of Poa annua and Senecio vulgaris in nursery stocks imported to Norway or inland-raised. Second International Weed Control Congress, Copenhagen, 364-468.
94. Palm HL, Rigglemann JD & Allison DA (1980) World review on the new serial herbicides - DPX 4198. Proceedings 1980 British Crop Protection Conference - Weeds. British Crop Protection Council, Croydon, UK, 1-6.
95. Pedersen BP, Neve P, Andreasen C & Powles SB (2007) Ecological fitness of a glyphosate-resistant Lolium rigidum population: growth and seed production along a competition gradient. Basic and Applied Ecology 8, 258-268.
96. Petzoldt K (1959) Wirkung des Mähdruschverfahrens auf die Verunkrautung. Zeitschrift für Acker-Pflanzenbau 109, 49.
97. Pinke G & Pal R (2008) Phytosociological and conservation study of the arable weed communities in western Hungary. Plant Biosystems 142, 491-508.
98. Pollard F, Moss SR, Cussans GW & Froud-Williams RJ (1982) The influence of tillage on the weed flora in a succession of winter wheat crops on a clay loam soil and silt loam soil. Weed Research 22, 129-136.
99. Ponce GR & Señas R (1983) Experiments with isoproturon for the control of weds in cereal crops. Weed Research 23, 39-43.
100. Putwain PD, Scott KR & Hilliday RJ (1982) The nature of resistance to triazine herbicides: case histories of phenology and population studies. In: Herbicide Resistance in Plants (eds HM LeBaron & J Gressel), 99-115. John Wiley & Sons, New York, NY, USA.
101. Rademacher B (1950) Über die lichtverhältnisse in kulturpflanzenbeständen insbesondere in hinblick auf Unkrautwuchs. Zeitschrift für Acker- und Pflanzenbau 92, 129.
102. Rademacher B, Koch W & Hurle K (1970) Changes in the weed flora as the result of continuous cropping of cereals and the annual use of the same weed control measure since 1956. In: Proceedings of 10th British Weed Control Conference, 1-6. British Crop Protection Council.
103. Rasmussen J (2003) Punch planting, flame weeding and stale seedbed for weed control in row crops. Weed Research 43, 393-403.
104. Rasmussen J, Bibby BM & Schou AP (2008) Investigating the selectivity of weed harrowing with new methods. Weed Research 48, 523-532.
105. Raunkiær C (1934) The Lifeforms of Plants and Statistical Plant Geography. Clarendon Press, Oxford, UK.
106. Reintam E, Kuht J, Trukmann K & Raats V (2006) Soil compaction and fertilization effect on weed community and nutrient uptake on spring barley field. In: 17th Conference of the International-Soil-Tillage-Research-Organisation Soil management for Sustainability. Advances in Geoecology 38, 157-164.
107. Russell MH, Saladini JL & Lichtner F (2002) Sulfonylurea herbicides. Pesticide Outlook 13, 166-173.
108. Ryan GF (1970) Resistance of common groundsel to Simazine and Atrazine. Weed Science 18, 614-616.
109. Rydahl P, Fertin K, Mathiassen SK & Kristensen K (2005) Forekomst og bekæmpelse af væselhale. Frøavleren 8, 122-123.
110. Salonen J, Hyvönen T & Jalli H (2001) Weeds in spring cereal fields in Finland-a third survey. Agricultural and Food Science in Finland 10, 247-364.
111. Schou JS & Streibig JC (1999) Pesticide taxes in Scandinavia. Pesticide Outlook 10, 227-229.
112. Skaanild MT, Friis LC & Brimer L (2001) Interplant alkaloid variation and Senecio vernalis toxicity in cattle. Veterinary and Human Toxicology 43, 147-151.
113. Smart SM, Firbank LG, Bunce RGH & Watkins JW (2000) Quantifying changes in abundance of food plants for butterfly larvae and farmland birds. Journal of Applied Ecology 37, 398-414.
114. Squire GS, Brooks DR, Bohan DA, Champion GT et al. (2003) On the rationale and interpretation of the Farm Scale Evaluation of genetically modified herbicide-tolerant crops. Philosophical Transactions of the Royal Society B 358, 1779-1800.
115. Stace C (2001) New Flora of the British Isles, 2nd edn. Cambridge University Press, Cambridge, UK.
116. Streibig JC (1979) Numerical methods illustrating the phytosociology of crops in relation to weed flora. Journal of Applied Ecology 16, 577-587.
117. Sutcliffe OL & Kay QON (2000) Changes in the arable flora of central southern England since the 1960s. Biological Conservation 93, 1-8.
118. Svensson R & Wigren M (1983) Klättens historie och biologi I Sverige. Svensk botanisk tidsskrift 77, 165-190.
119. Tarmi S, Helenius J & Hyvönen T (2009) Importance of edaphic, spatial and management factors for plant communities of field boundaries. Agriculture, Ecosystems & Environment 131, 201-206.
120. Thies JE & Devare MH (2007) An ecological assessment of transgenic crops. Journal of Development Studies 43, 97-129.
121. Thorup S & Petersen HI (1970) National Research Center for Plant Protection, Institute for Weed Control, Flakkebjerg, unpublished data from 1944/45.
122. Tørrensen KS & Skuterud R (2002) Plant protection in spring cereal production with reduced tillage. IV. Changes in weed flora and weed seedbank. Crop Protection 21, 179-193.
123. Vanden Born WH (1971) Green foxtail: seed dormancy, germination and growth. Canadian Journal of Plant Science 51, 52-59.
124. Wallgren B & Avholm K (1978) Dormancy and Germination of Apera spica-venti L. and Alopecurus myosuroides Huds Seeds. Swedish Journal of Agricultural Research 8, 11-15.
125. Warwick SI (1979) The biology of Canadian weeds. 37. Poa annua L. Canadian Journal Plant Science 59, 103-106.
126. Wilson JD, Morris AJ, Arroyo BE, Clark SC et al. (1999) A review of the abundance and diversity of invertebrate and plant foods of granivorous birds in northern Europe in relation to agricultural change. Agriculture, Ecosystems & Environment 75, 13-30.
127. Zayas L, Pomeranz Y & Lai FS (1989) Discrimination of wheat and nonwheat components in grain samples by image analysis. Cereal Chemistry 66, 233-237.