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High Seed Retention at Maturity of Annual Weeds Infesting Crop Fields Highlights the Potential for Harvest Weed Seed Control

  • Michael J. Walsh (a1) and Stephen B. Powles (a1)


Seed production of annual weeds persisting through cropping phases replenishes/establishes viable seed banks from which these weeds will continue to interfere with crop production. Harvest weed seed control (HWSC) systems are now viewed as an effective means of interrupting this process by targeting mature weed seed, preventing seed bank inputs. However, the efficacy of these systems is directly related to the proportion of total seed production that the targeted weed species retains (seed retention) at crop maturity. This study determined the seed retention of the four dominant annual weeds of Australian cropping systems - annual ryegrass, wild radish, brome grass, and wild oat. Beginning at the first opportunity for wheat harvest and on a weekly basis for 28 d afterwards the proportion of total seed production retained above a 15 cm harvest cutting height was determined for these weed species present in wheat crops at nine locations across the Western Australian (WA) wheat-belt. Very high proportions of total seed production were retained at wheat crop maturity for annual ryegrass (85%), wild radish (99%), brome grass (77%), and wild oat (84%). Importantly, seed retention remained high for annual ryegrass and wild radish throughout the 28 d harvest period. At the end of this period, 63 and 79% of total seed production for annual ryegrass and wild radish respectively, was retained above harvest cutting height. However, seed retention for brome grass (41%) and wild oat (39%) was substantially lower after 28 d. High seed retention at crop maturity, as identified here, clearly indicates the potential for HWSC systems to reduce seed bank replenishment and diminish subsequent crop interference by the four most problematic species of Australian crops.

La producción de semilla de malezas anuales, que persisten a lo largo de las fases de la producción de cultivos, repone/establece bancos de semilla viables a partir de los cuales estas malezas continuarán interfiriendo con la producción de cultivos. El control de semillas de malezas mediante sistemas de cosecha (HWSC) es ahora visto como un medio efectivo para interrumpir este proceso al enfocarse en semillas maduras de malezas, previniendo la entrada de nuevas semillas en el banco de semillas. Sin embargo, la eficacia de estos sistemas está directamente relacionada a la proporción del total de semilla producida que la especie de maleza retiene (retención de semilla) al momento de la madurez del cultivo. Este estudio determinó la retención de semilla de cuatro malezas anuales dominantes en sistemas de cultivos Australianos -Lolium rigidum, Raphanus raphanistrum, Bromus spp., y Avena fatua. Empezando en la primera oportunidad de cosecha de trigo, y siguiendo intervalos semanales durante 28 d, se determinó la proporción del total de la semilla producida que fue retenida sobre 15 cm (altura de corte de la cosechadora) para estas especies de malezas presentes en campos de trigo, en nueve localidades a lo largo de la faja de trigo en el oeste de Australia (WA). Proporciones muy altas de la semilla total producida fue retenida al momento de la madurez del trigo para L. rigidum (85%), R. raphanistrum (99%), Bromus spp. (77%), y A. fatua (84%). Importantemente, la retención de semilla se mantuvo alta para L. rigidum y R. raphanistrum durante los 28 d del período de cosecha. Al final de este período, se retuvo 63 y 79% del total de la semilla producida de L. rigidum y R. raphanistrum, respectivamente, por encima de la altura de corte de cosecha. Sin embargo, la retención de semilla para Bromus spp. (41%) y A. fatua (39%) fue sustancialmente menor después de 28 d. Alta retención de semilla al momento de la madurez del cultivo, como se identificó aquí, claramente indica el potencial de los sistemas HWSC para reducir la recuperación del banco de semillas y disminuir así la interferencia con el cultivo de cuatro de las especies de enivos reponecciones ar el daño que persisten a lo largo de las fases de la producci de daño para hacer proyecciones ar el daño enmalezas más problemáticas en cultivos Australianos.


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Angus, JF (2001) Nitrogen supply and demand in Australian agriculture. (Special Issue: Meeting future and current needs for on-farm nitrogen). Aust J Exp Agric 41:277288
Balsari, P, Finassi, A, Airoldi, G (1994) Development of a device to separate weed seeds harvested by a combine and reduce their degree of germination. 12th World Congress of the International Commission of Agricultural Engineers Report No. 94-D-062. Pages 942p
Barroso, J, Navarrete, L, Sánchez Del Arco, MJ, Fernandez-Quintanilla, C, Lutman, PJW, Perry, NH, Hull, RI (2006) Dispersal of Avena fatua and Avena sterilis patches by natural dissemination, soil tillage and combine harvesters. Weed Res 46:118128
Bhatti, MA (2004) Genetic variation in naturalized wild radish (Raphanus raphanistrum L.) populations in the mediterranean climate of south-western Australia. PhD dissertation Perth: University of Western Australia. 133p
Blanco-Moreno, JM, Chamorro, L, Masalles, RM, Recasens, J, Sans, FX (2004) Spatial distribution of Lolium rigidum seedlings following seed dispersal by combine harvesters. Weed Res 44:375387
BOM (2008) Bureau of Meteorology Weather and Climate Statistics. Accessed: Feburary 25, 2014
Boutsalis, P, Gill, GS, Preston, C (2012) Incidence of herbicide resistance in rigid ryegrass (Lolium rigidum) across Southeastern Australia. Weed Technol 26:391398
Broster, JC, Pratley, J (2006) A decade of monitoring herbicide resistance in Lolium rigidum in Australia. Aust J Exp Agric 46:11511160
Donald, CM (1965) The progress of Australian agriculture and the role of pastures in environmental change. Aust J Sci 27:187198
Duke, SO (2012) Why have no new herbicide modes of action appeared in recent years? Pest Manage Sci 68:505512
Feldman, M, Reed, WB (1974) Distribution of wild oat seeds during cereal crop swathing and combining. Pages 110 in 1974 Annual meeting of the Canadian Society of Agricultural Engineering. Ste. Foy, PQ: Laval University
Howard, CL, Mortimer, AM, Gould, P, Putwain, PD, Cousens, R, Cussens, GW (1991) The dispersal of weeds—seed movement in arable agriculture. Pages 664673 in Proceedings Brighton Crop Protection Conference—Weeds. Lavenham, UK The Lavenham Press
Kleemann, SGL, Gill, GS (2009) Population Ecology and Management of Rigid Brome (Bromus rigidus) in Australian Cropping Systems. Weed Sci 57:202207
Kloot, P (1983) The Genus Lolium in Australia. Aust J Bot 31:421435
Kon, KF, Blacklow, WM (1989) Identification, distribution and population variability of great brome (Bromus diandrus Roth.) and rigid brome (Bromus rigidus Roth.). Aust J Agric Res 39:10391050
Owen, MJ, Martinez, NJ, Powles, SB (2014) Multiple herbicide-resistant Lolium rigidum (annual ryegrass) now dominates across the Western Australian grain belt. Weed Res. DOI:
Paterson, JG (1976) The distribution of Avena species naturalized in Western Australia. J Appl Ecol 13:257
Radford, BJ, Wilson, BJ, Cartledge, O, Watkins, FB (1980) Effect of wheat seeding rate on wild oat competition. Aust J Exp Agric Anim Husb 20:7781
Reeves, TG (1976) Effect of annual ryegrass (Lolium rigidum Gaud.) on yield of wheat. Weed Res 16:5763
Reeves, TG, Code, GR, Piggin, CM (1981) Seed production and longevity, seasonal emergence and phenology of wild radish (Raphanus raphanistrum L.). Aust J Exp Agric Anim Husb 21:524530
Rew, LJ, Froud-Williams, RJ, Boatman, ND (1996) Dispersal of Bromus sterilis and Anthriscus sylvestris seed within arable field margins. Agric Ecosyst Environ 59:107114
Shirtliffe, SJ, Entz, MH (2005) Chaff collection reduces seed dispersal of wild oat (Avena fatua) by a combine harvester. Weed Sci 53:465470
Shirtliffe, SJ, Entz, MH, Van Acker, RC 2000. Avena fatua development and seed shatter as related to thermal time. Weed Sci 48:555560
Taghizadeh, MS, Nicolas, ME, Cousens, RD (2012) Effects of relative emergence time and water deficit on the timing of fruit dispersal in Raphanus raphanistrum L. Crop Pasture Sci 63:10181025
Walker, SR, Medd, RW, Robinson, GR, Cullis, BR (2002) Improved management of Avena ludoviciana and Phalaris paradoxa with more densely sown wheat and less herbicide. Weed Res 42:257270
Walsh, MJ, Harrington, RB, Powles, SB (2012) Harrington seed destructor: A new nonchemical weed control tool for global grain crops. Crop Sci 52:13431347
Walsh, MJ, Minkey, DM (2006) Wild radish (Raphanus raphanistrum L.) development and seed production in response to time of emergence, crop-topping and sowing rate of wheat. Plant Prot Quart 21:2529
Walsh, MJ, Newman, P (2007) Burning narrow windrows for weed seed destruction. Field Crops Res 104:2440
Walsh, MJ, Newman, P, Powles, SB (2013) Targeting Weed Seeds In-Crop: A New Weed Control Paradigm for Global Agriculture. Weed Technol 27:431436
Walsh, MJ, Owen, MJ, Powles, SB (2007) Frequency and distribution of herbicide resistance in Raphanus raphanistrum populations randomly collected across the Western Australia wheatbelt. Weed Res 47:542550
Walsh, MJ and Powles, SB (2007) Management strategies for herbicide-resistant weed populations in Australian dryland crop production systems. Weed Technol. 21:332338.
Wilson, BJ (1970) Studies on the shedding of seed of Avena fatua in various cereal crops and the presence of the seed in the harvested matter. Pages 831836 in Proceedings Brighton Crop Protection Conference-Weeds. Croydon, Great Britain British Crop Protection Council.
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Weed Technology
  • ISSN: 0890-037X
  • EISSN: 1550-2740
  • URL: /core/journals/weed-technology
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