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Effect of Herbicide Systems on Weed Shifts in Soybean and Cotton

  • S. Gregory Flint (a1), David R. Shaw (a1), Franklin S. Kelley (a1) and James C. Holloway (a2)

Abstract

Field studies were conducted from 1998 through 2000 to compare weed population shifts in soybean and cotton using a total glyphosate system, preemergence (PRE) herbicides followed by glyphosate, and a conventional herbicide program. In the first year of the soybean study, populations of hemp sesbania were highest for treatments of PRE herbicides followed by either glyphosate or the conventional herbicide program because of better control from the total glyphosate system. Barnyardgrass populations in the first year of the study for the nontreated plots were 0 plants/m2 but increased in the third year to 61 plants/m2. Flumetsulam plus metolachlor followed by glyphosate at the lower rates and the nontreated check were the only treatments in which there was an increase in barnyardgrass over the 3-yr study. Broadleaf signalgrass populations increased in the third year with 0.1 kg ai/ha flumetsulam plus 2.1 kg ai/ha metolachlor followed by 0.84 kg ae/ha glyphosate, primarily because of reduced competition from lower populations of other weeds such as hemp sesbania. Pitted morningglory populations for all treatments decreased in the third year because of good control of this species and the high level of interference from other weed species in the first 2 yr. Johnsongrass populations decreased in the third year with 0.4 kg ai/ha flumetsulam plus 1.1 kg ai/ha metolachlor followed by 0.84 kg/ha glyphosate. Johnsongrass populations decreased with timely glyphosate sequential applications, with 5 plants/m2 in 1998 and 0 plants/m2 in 2000. Yields increased from the first year to the second year, corresponding to reduced weed pressure, and yields varied from 710 to 1,420 kg/ha. Because of weed pressure, soybean yields were not different in any of the treatments, including the nontreated, although treatments changed the species present. In the cotton study, weed populations over the 3 yr decreased, with the most significant reductions from the treatments of fluometuron plus prometryn plus metolachlor followed by either pyrithiobac or glyphosate. Weeds that showed the most significant decline were barnyardgrass and hemp sesbania, whereas johnsongrass increased, with 27 plants/m2 in treatments of 0.6 kg ai/ha fluometuron plus 0.3 kg ai/ha prometryn plus 0.7 kg ai/ha metolachlor followed by 0.84 kg/ha glyphosate. Lint cotton yields varied from 0 to 128 kg/ha. Because of the weed pressure, cotton yields were not different in any of the treatments, although treatments changed the species present. This research has shown that weed species can decrease over time with the continued use of any of these herbicide programs.

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Corresponding author

Corresponding author's E-mail: dshaw@gri.msstate.edu

References

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Bello, I. A., Owen, M. D. K., and Hetterman-Valenti, H. M. 1995. Effect of shade on weed growth, seed production, and dormancy. Weed Technol. 9:452455.
Brown, S. M. 1997. Potential fit of Roundup Ready cotton in Georgia. in Dugger, P. and Richter, D., eds. Proceedings of the Beltwide Cotton Conferences. Memphis, TN: National Cotton Council of America. P. 479.
Clements, D. R., Weise, S. F., and Swanton, C. J. 1994. Integrated weed management and weed species diversity. Phytoprotection 75:118.
Culpepper, A. S. and York, A. C. 1998. Weed management in glyphosate-tolerant cotton. J. Cotton Sci. 4:174185.
Dowler, C. C. 1997. Weed survey-Southern states. Grass crops subsection. Proc. South. Weed Sci. Soc. 50:227272.
Elmore, C. D., Wiseman, J. B., and McDaniel, J. 1987. Morningglory survey of cotton and soybean fields in the Mississippi Delta. Proc. South. Weed Sci. Soc. 36:319328.
Frick, B. and Thomas, A. G. 1992. Weed surveys in different tillage systems in southwestern Ontario field crops. Can J. Plant Sci. 72:13371347.
Grossbard, E. and Atkinson, D. 1985. The Herbicide Glyphosate. London: Butterworth. 490 p.
Isgett, T. D., Murdock, E. C., and Keeton, A. 1997. Weed control in Roundup Ready cotton. in Proceedings of the Beltwide Cotton Research conference. Memphis, TN: National Cotton Council of America. P. 342.
Johnson, W. G. and Frans, R. E. 1991. Johnsongrass (Sorghum halepense) control in soybean (Glycine max) with postemergence herbicides. Weed Technol. 5:8791.
Lindwall, C. W., Larney, F. J., Johnston, A. M., and Moyer, J. R. 1994. Crop management in conservation tillage systems. in Unger, P. W., ed. Managing Agricultural Residues. Boca Raton, FL: Lewis. Pp. 185209.
McWhorter, C. G. and Anderson, J. M. 1979. Hemp sesbania (Sesbania exaltata) competition in soybean (Glycine max). Weed Sci. 27:5864.
Sims, B. D. and Oliver, L. R. 1990. Mutual influences of seedling johnsongrass (Sorghum halepense), sicklepod (Senna obtusifolia) and soybean (Glycine max). Weed Sci. 38:139147.
Sprankle, P. L., Parker, W. B., Miller, K. J., and Wells, B. H. 1994. Weed control with Roundup Ready soybeans. Proc. South. Weed Sci. Soc. 50:3940.
York, A. C. 1995. Weed management with Roundup Ready soybean. Proc. South. Weed Sci. Soc. 48:3435.

Keywords

Effect of Herbicide Systems on Weed Shifts in Soybean and Cotton

  • S. Gregory Flint (a1), David R. Shaw (a1), Franklin S. Kelley (a1) and James C. Holloway (a2)

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