Application of a preplant or preemergence glyphosate burndown is routine
in most no-tillage production systems of annual crops, however, time of
application may influence overall weed control and grain yield. Six field
trials were conducted over a three-year period (2008, 2009 and 2010) near Ridgetown,
Ontario, Canada to determine the effect of glyphosate burndown application
timing in glyphosate-resistant (GR) no-tillage soybean [Glycine max (L.) Merr.]. Soybean growth was reduced 5%, 10% and 20%
when the burndown was delayed to 1, 5 and 12 days after planting (DAP), when
evaluated one week after application (WAA), respectively. By 8 WAA, predicted
burndown timing increased to 9, 14 and 23 DAP, and was 10, 17 and 26 DAP at 12
WAA, to reduce soybean growth by 5%, 10% and 20%, respectively. Similarly,
burndown application at 14, 21 and 30 DAP corresponded to a soybean yield
reduction of 5%, 10% and 20%. Seed moisture content was generally insensitive
to burndown timing; 80 and 140 DAP were required to increase moisture by 5% and
10%, respectively. This research indicates that delaying glyphosate burndown by
up to 14 DAP, approximately VE to VC growth stage, has the potential to result
in a modest reduction in soybean yield (5%).
References
[1]
Statistics Canada (2014) Production of Principle Field Crops, September 2014.
http://www.statcan.gc.ca/daily-quotidien/141003/dq141003b-eng.htm
[2]
Kulasekera, K. (2014) Estimated Area, Yield, Production and Farm Value of Specified Field Crops, Ontario, 2011-2013. Ontario Ministry of Agriculture, Food and Rural Affairs.
http://www.omafra.gov.on.ca/english/stats/crops/estimate_new.htm
Duke, S.O. and Powles, S.B. (2008) Glyphosate: A Once-in-a-Century Herbicide. Pest Management Science, 64, 319-325. http://dx.doi.org/10.1002/ps.1518
[5]
Beckie, H.J., et al. (2006) A Decade of Herbicide-Resistant Crops in Canada. Canadian Journal of Plant Science, 86, 1243-1264. http://dx.doi.org/10.4141/P05-193
[6]
Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) (2013) Guide to Weed Control 2014-2015: Publication 75. Queen’s Printer for Ontario, Toronto.
[7]
Owen, M.D. (2008) Weed Species Shifts in Glyphosate-Resistant Crops. Pest Management Science, 64, 377-387.
http://dx.doi.org/10.1002/ps.1539
[8]
Marra, M.C., Piggott, N.E. and Carlson, G.A. (2004) The Net Benefits, Including Convenience, of Roundup Ready? Soybeans: Results from a National Survey, Technical Bulletin 2004-3. NSF Center for Integrated Pest Management, Ralieigh.
[9]
Gonzini, L.C., Hart, S.E. and Wax, L.M. (1999) Herbicide Combinations for Weed Management in Glyphosate-Resistant Soybean (Glycinemax). Weed Technology, 13, 354-360.
[10]
Van Acker, R.C., Swanton, C.J. and Weise, S.F. (1993) The Critical Period of Weed Control in Soybean [Glycinemax (L.) Merr.], Weed Science, 41, 194-200.
[11]
Vangessel, M.J., Ayeni, A.O. and Majek, B.A. (2000) Optimum Glyphosate Timing with or without Residual Herbicides in Glyphosate-Resistant Soybean (Glycine max) under Full-Season Conventional Tillage, Weed Technology, 14, 140-149. http://dx.doi.org/10.1614/0890-037X(2000)014[0140:OGTWOW]2.0.CO;2
[12]
Seefeldt, S.S., Jensen, J.E. and Fuerst, E.P. (1995) Log-Logistic Analysis of Herbicide Dose-Response Relationships. Weed Technology, 9, 218-227.
[13]
Bowley, S. (1999) A Hitchhiker’s Guide to Statistics in Plant Biology. AnyOldSubjectBooks, Guelph.
[14]
Vangessel, M.J., Ayeni, A.O. and Majek, B.A. (2001) Glyphosate in Full-Season No-Till Gly-phosate-Resistant Soybean: Role of Preplant Applications and Residual Herbicides. Weed Technology, 15, 714-724.
http://dx.doi.org/10.1614/0890-037X(2001)015[0714:GIFSNT]2.0.CO;2
[15]
Tharp, B.E. and Kells, J.J. (2001) Delayed Burndown in No-Tillage Glyphosate-Resistant Corn (Zea mays) Planted into Soybean (Glycine max) Residue and a Wheat (Triticum aestivum) Cover Crop. Weed Technology, 15, 467-473.
http://dx.doi.org/10.1614/0890-037X(2001)015[0467:DBINTG]2.0.CO;2
[16]
Cox, W.J., Hahn, R. and Stachowski, P.J. (2006) Time of Weed Removal with Glyphosate Affects Corn Growth and Yield Components. Agronomy Journal, 98, 349-353. http://dx.doi.org/10.2134/agronj2005.0078
[17]
Mulugeta, D. and Boerboom, C.M. (2000) Critical Time of Weed Removal in Glyphosate-Resistant Glycinemax. Weed Science, 48, 35-42. http://dx.doi.org/10.1614/0043-1745(2000)048[0035:CTOWRI]2.0.CO;2
[18]
Swanton, C.J., Shrestha, A., Chandler, K. and Deen, W. (2000) An Economic Assessment of Weed Control Strategies in No-Till Glyphosate-Resistant Soybean (Glycinemax). Weed Technology, 14, 755-763.
http://dx.doi.org/10.1614/0890-037X(2000)014[0755:AEAOWC]2.0.CO;2
[19]
Johnson, W.G., Gibson, K.D. and Conley, S.P. (2007) Does Weed Size Matter? An Indiana Grower Perspective about Weed Control Timing. Weed Technology, 21, 542-546. http://dx.doi.org/10.1614/WT-06-094R.1