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Management of Pigweed (Amaranthus spp.) in Glufosinate-Resistant Soybean in the Midwest and Mid-South

  • Thomas R. Butts (a1), Jason K. Norsworthy (a2), Greg R. Kruger (a3), Lowell D. Sandell (a4) (a5), Bryan G. Young (a6) (a7), Lawrence E. Steckel (a8), Mark M. Loux (a9), Kevin W. Bradley (a10), Shawn P. Conley (a1), David E. Stoltenberg (a1), Francisco J. Arriaga (a11) and Vince M. Davis (a1) (a12)...


Pigweeds are among the most abundant and troublesome weed species across Midwest and mid-South soybean production systems because of their prolific growth characteristics and ability to rapidly evolve resistance to several herbicide sites of action. This has renewed interest in diversifying weed management strategies by implementing integrated weed management (IWM) programs to efficiently manage weeds, increase soybean light interception, and increase grain yield. Field studies were conducted across 16 site-years to determine the effectiveness of soybean row width, seeding rate, and herbicide strategy as components of IWM in glufosinate-resistant soybean. Sites were grouped according to optimum adaptation zones for soybean maturity groups (MGs). Across all MG regions, pigweed density and height at the POST herbicide timing, and end-of-season pigweed density, height, and fecundity were reduced in IWM programs using a PRE followed by (fb) POST herbicide strategy. Furthermore, a PRE fb POST herbicide strategy treatment increased soybean cumulative intercepted photosynthetically active radiation (CIPAR) and subsequently, soybean grain yield across all MG regions. Soybean row width and seeding rate manipulation effects were highly variable. Narrow row width (≤ 38 cm) and a high seeding rate (470,000 seeds ha−1) reduced end-of-season height and fecundity variably across MG regions compared with wide row width (≥ 76 cm) and moderate to low (322,000 to 173,000 seeds ha−1) seeding rates. However, narrow row widths and high seeding rates did not reduce pigweed density at the POST herbicide application timing or at soybean harvest. Across all MG regions, soybean CIPAR increased as soybean row width decreased and seeding rate increased; however, row width and seeding rate had variable effects on soybean yield. Furthermore, soybean CIPAR was not associated with end-of-season pigweed growth and fecundity. A PRE fb POST herbicide strategy was a necessary component for an IWM program as it simultaneously managed pigweeds, increased soybean CIPAR, and increased grain yield.

Las especies del género Amaranthus están entre las especies de malezas más abundantes y problemáticas en los sistemas de producción de soja en el medio oeste y el sur medio debido a sus características de crecimiento prolífico y su habilidad para evolucionar rápidamente resistencia a varios sitios de acción de herbicidas. Esto ha renovado el interés en la diversificación de estrategias de manejo de malezas implementando programas de manejo integrado de malezas (IWM) para manejar eficientemente a las malezas, que incluyan una mayor intercepción de luz por parte de la soja a la vez que se aumente el rendimiento de grano. Se realizaron estudios de campo a lo largo de 16 sitios-años para determinar la efectividad de la distancia entre hileras, densidad de siembra, y la estrategia de herbicidas, como componentes de un IWM en soja resistente a glufosinate. Los sitios fueron agrupados de acuerdo a las zonas óptimas de adaptación según los grupos de madurez (MGs) de la soja. Al promediar todas las regiones MG, la densidad y altura de Amaranthus, al momento de la aplicación POST del herbicida, y la densidad, la altura y la fecundidad de Amaranthus al final de la temporada, fueron reducidas en programas IWM que usaron una estrategia de herbicidas PRE seguidos por (fb) POST. Además, un tratamiento con una estrategia de herbicidas PRE fb POST aumentó la intercepción acumulativa de radiación fotosintéticamente activa (CIPAR) de la soja y subsecuentemente el rendimiento de grano de la soja al promediar todas las regiones MG. Los efectos de la distancia entre hileras y la densidad de siembra de la soja fueron altamente variables. Hileras angostas (≤ 38 cm) y una alta densidad de siembra (470,000 semillas ha−1) redujeron la altura y la fecundidad al final de la temporada en forma variable entre las regiones MG al compararse con hileras anchas (≥ 76 cm) y densidades de siembra de moderadas a bajas (322,000 a 173,000 semillas ha−1). Sin embargo, las hileras angostas y las altas densidades de siembra no redujeron la densidad de Amaranthus al momento de la aplicación de herbicida POST o al momento de la cosecha de la soja. Al promediar todas las regiones MG, la CIPAR de la soja aumentó al disminuir la distancia entre hileras e incrementar la densidad de siembra. Sin embargo, la distancia entre hileras y la densidad de siembra tuvieron efectos variables sobre el rendimiento de la soja. Adicionalmente, la CIPAR de la soja no estuvo asociada con el crecimiento ni la fecundidad de Amaranthus al final de la temporada. Una estrategia que use herbicidas PRE fb POST fue un componente necesario para que el programa IWM simultáneamente manejara malezas Amaranthus e incrementara la CIPAR de la soja y su rendimiento de grano.


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Current address: Department of Agronomy and Horticulture, University of Nebraska-Lincoln, North Platte, NE 69101.

Associate Editor for this paper: Mark VanGessel, University of Delaware.



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Arce, GD, Pedersen, P, Hartzler, RG (2009) Soybean seeding rate effects on weed management. Weed Technol 23:1722
Ball, RA, Purcell, LC, Carey, SK (2004) Evaluation of solar radiation prediction models in North America. Agron J 96:391397
Bell, MS, Hager, AG, Tranel, PJ (2013) Multiple resistance to herbicides from four site-of-action groups in waterhemp (Amaranthus tuberculatus). Weed Sci 61:460468
Bensch, CN, Horak, MJ, Peterson, D (2003) Interference of redroot pigweed (Amaranthus retroflexus), Palmer amaranth (A. palmeri), and common waterhemp (A. rudis) in soybean. Weed Sci 51:3743
Board, JE, Harville, BG (1993) Soybean yield component responses to a light interception gradient during the reproductive period. Crop Sci 33:772777
Box, GEP, Cox, DR (1964) An analysis of transformations. J R Stat Soc B Met 26:211252
Carpenter, AC, Board, JE (1997) Branch yield components controlling soybean yield stability across plant populations. Crop Sci 37:885891
Conley, SP, Gaska, J (2010) Factors to Consider if Using Lower Soybean Seeding Rates in 2010. University of Wisconsin-Extension. Accessed April 10, 2012
Cox, WJ, Cherney, JH (2011) Growth and yield responses of soybean to row spacing and seeding rate. Agron J 103:123128
Culpepper, AS, Grey, TL, Vencill, WK, Kichler, JM, Webster, TM, Brown, SM, York, AC, Davis, JW, Hanna, WW (2006) Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) confirmed in Georgia. Weed Sci 54:620626
Davis, VM (2010) Soybean Seeding Rates for 2010. The Bulletin: Pest Management and Crop Development Information for Illinois. Pages 4 p
De Bruin, JL, Pedersen, P (2008) Effect of row spacing and seeding rate on soybean yield. Agron J 100:704710
De Bruin, JL, Pedersen, P (2009) New and old soybean cultivar responses to plant density and intercepted light. Crop Sci 49:22252232
DeWerff, RP, Conley, SP, Colquhoun, JB, Davis, VM (2014) Can soybean seeding rate be used as an integrated component of herbicide resistance management? Weed Sci 62:625636
Diebold, RS, McNaughton, KE, Lee, EA, Tardif, FJ (2003) Multiple resistance to imazethapyr and atrazine in Powell amaranth (Amaranthus powellii). Weed Sci 51:312318
Edwards, JT, Purcell, LC, Karcher, DE (2005) Soybean yield and biomass responses to increasing plant population among diverse maturity groups: II. Light interception and utilization. Crop Sci 45:17781785
Hanna, SO, Conley, SP, Shaner, GE, Santini, JB (2008) Fungicide application timing and row spacing effect on soybean canopy penetration and grain yield. Agron J 100:14881492
Heap, I (2014) The International Survey of Herbicide Resistant Weeds. Accessed November 1, 2014
Horak, MJ, Loughin, TM (2000) Growth analysis of four Amaranthus species. Weed Sci 48:347355
Jha, P, Norsworthy, JK, Bridges, W Jr., Riley, MB (2008) Influence of glyphosate timing and row width on Palmer amaranth (Amaranthus palmeri) and pusley (Richardia spp.) demographics in glyphosate-resistant soybean. Weed Sci 56:408415
Johnson, WG, Gibson, KD, Conley, SP (2007) Does weed size matter? An Indiana grower perspective about weed control timing. Weed Technol 21:542546
Karcher, DE, Richardson, MD (2005) Batch analysis of digital images to evaluate turfgrass characteristics. Crop Sci 45:15361539
Lambert, DM, Lowenberg-DeBoer, J (2003) Economic analysis of row spacing for corn and soybean. Agron J 95:564573
Légère, A, Schreiber, MM (1989) Competition and canopy architecture as affected by soybean (Glycine max) row width and density of redroot pigweed (Amaranthus retroflexus). Weed Sci 37:8492
McWilliams, DA, Berglund, DR, Endres, GJ (1999) Soybean Growth and Management Quick Guide. North Dakota State University-Extension Service, A-1174. Pages 8 p
Monteith, JL (1977) Climate and the efficiency of crop production in Britain. Phil Trans R Soc B Biol Sci 281:277294
Norsworthy, JK, Ward, SM, Shaw, DR, Llewellyn, RS, Nichols, RL, Webster, TM, Bradley, KW, Frisvold, G, Powles, SB, Burgos, NR, Witt, WW, Barrett, M (2012) Reducing the risks of herbicide resistance: best management practices and recommendations. Weed Sci 60:3162
Pedersen, P (2007) Managing Soybean for High Yield. Iowa State University Extension. Accessed April 22, 2012
Purcell, LC (2000) Soybean canopy coverage and light interception measurements using digital imagery. Crop Sci 40:834837
Riar, DS, Norsworthy, JK, Steckel, LE, Stephenson, DO IV, Eubank, TW, Bond, J, Scott, RC (2013a) Adoption of best management practices for herbicide-resistant weeds in midsouthern United States cotton, rice, and soybean. Weed Technol 27:788797
Riar, DS, Norsworthy, JK, Steckel, LE, Stephenson, DO IV, Eubank, TW, Scott, RC (2013b) Assessment of weed management practices and problem weeds in Midsouth U.S. soybean: a consultant's perspective. Weed Technol 27:612622
Robinson, AP, Conley, SP (2007) Plant populations and seeding rates for soybeans. West Lafayette, IN: Purdue University Publication No. AY-217-W. Soybean Production Systems: Purdue Extension. Pages 3 p
Sellers, BA, Smeda, RJ, Johnson, WG, Kendig, JA, Ellersieck, MR (2003) Comparative growth of six Amaranthus species in Missouri. Weed Sci 51:329333
Suhre, JJ, Weidenbenner, NH, Rowntree, SC, Wilson, EW, Naeve, SL, Conley, SP, Casteel, S, Diers, BW, Esker, PD, Specht, JE, Davis, VM (2014) Soybean yield partitioning changes revealed by genetic gain and seeding rate interactions. Agron J 106:112
Swanton, CJ, Weise, SF (1991) Integrated weed management: the rationale and approach. Weed Technol 5:657663
[USDA-NASS] U.S. Department of Agriculture National Agricultural Statistics Service (2013) Quick Stats. Accessed March 15, 2015
Vencill, WK, Nichols, RL, Webster, TM, Soteres, JK, Mallory-Smith, C, Burgos, NR, Johnson, WG, McClelland, MR (2012) Herbicide resistance: toward an understanding of resistance development and the impact of herbicide-resistant crops. Weed Sci 60:230
Walker, RH, Buchanan, GA (1982) Crop manipulation in integrated weed management systems. Weed Sci 30:1724
Wax, LM, Pendleton, JW (1968) Effect of row spacing on weed control in soybeans. Weed Sci 16:462465
Yelverton, FH, Coble, HD (1991) Narrow row spacing and canopy formation reduces weed resurgence in soybeans (Glycine max). Weed Technol 5:169174
Zhang, LX, Kyei-Boahen, S, Zhang, J, Zhang, MH, Freeland, TB, Watson, CE, Liu, X (2007) Modifications of optimum adaptation zones for soybean maturity groups in the USA. Crop Manage 6. DOI:


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Management of Pigweed (Amaranthus spp.) in Glufosinate-Resistant Soybean in the Midwest and Mid-South

  • Thomas R. Butts (a1), Jason K. Norsworthy (a2), Greg R. Kruger (a3), Lowell D. Sandell (a4) (a5), Bryan G. Young (a6) (a7), Lawrence E. Steckel (a8), Mark M. Loux (a9), Kevin W. Bradley (a10), Shawn P. Conley (a1), David E. Stoltenberg (a1), Francisco J. Arriaga (a11) and Vince M. Davis (a1) (a12)...


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