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Influence of Quackgrass (Agropyron repens) Density and Duration of Interference on Soybeans (Glycine max)

  • Frank L. Young (a1), Donald L. Wyse (a1) and Robert J. Jones (a1)


The effect of quackgrass [Agropyron repens (L.) Beauv.] density and duration of interference on soybeans [Glycine max (L.) Merr.] was investigated in two studies. In the density study, the average reduction in soybean yield by quackgrass densities of 520 and 910 shoots/m2 was 19 and 55%, respectively. Quackgrass densities of 95 and 160 shoots/m2 did not significantly reduce soybean yields. The number of branches that produced pods, the number of pods and seeds per plant, and soybean height were reduced by the two highest densities. In 1980, quackgrass densities of 265 and 595 shoots/m2 reduced soybean leaf area and plant dry weight. Leaf area partitioning (LAP), leaf weight partitioning (LWP), and net assimilation rate (NAR) of soybeans were reduced by a quackgrass density of 595 shoots/m2. In the duration study, interference by a natural stand of quackgrass for 6 weeks, 8 weeks, and full-season decreased soybean yield an average of 11, 23, and 33%, respectively. Results from the duration study suggest that a selective postemergence herbicide for the control of quackgrass in soybeans would be beneficial if available.



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1. Barrentine, W. L. 1974. Common cocklebur competition on soybeans. Weed Sci. 22:600603.
2. Burnside, O. C. 1979. Soybean (Glycine max) growth as affected by weed removal, cultivar, and row spacing. Weed Sci. 27:562565.
3. Coble, H. D. and Ritter, R. L. 1978. Pennsylvania smartweed (Polygonum pensylvanicum) interference in soybeans (Glycine max . Weed Sci. 26:556559.
4. Eaton, B. J., Feltner, K. C., and Russ, O. G. 1973. Vernice mallow competition in soybeans. Weed Sci. 21:224228.
5. Elakkad, M. A. and Behrens, R. 1978. Canada thistle [Cirsium arvense (L.) Scop.] competition with corn and soybeans for water, nutrients, and light. Abstr., Weed Sci. Soc. Am. p. 65.
6. Geddes, R. D., Scott, H. D., and Oliver, L. R. 1979. Growth and water use by common cocklebur (Xanthium pensylvanicum) and soybeans (Glycine max) under field conditions. Weed Sci. 27:206212.
7. Hagood, E. S. Jr., Bauman, T. T., Williams, J. L. Jr., and Schreiber, M. M. 1980. Growth analysis of soybeans (Glycine max) in competition with velvetleaf (Abutilon theophrasti . Weed Sci. 28:729734.
8. Knake, E. L. and Slife, F. W. 1962. Competition of Setaria faberii with corn and soybeans. Weeds. 10:2629.
9. Knake, E. L. and Slife, F. W. 1969. Effect of time of giant foxtail removal from corn and soybeans. Weed Sci. 17:281283.
10. Kommedahl, T., Old, K. M., Ohman, J. H., and Ryan, E. W. 1970. Quackgrass and nitrogen effects on succeeding crops in the field. Weed Sci. 18:2932.
11. McWhorter, C. G. and Anderson, J. M. 1979. Hemp sesbania (Sesbania exaltata) competition in soybeans (Glycine max . Weed Sci. 27:5864.
12. Modani, M. K., Knake, E. L., and Slife, F. W. 1964. Competition of smooth pigweed with corn and soybeans. Weeds 12:216218.
13. Oliver, L. R. 1979. Influence of soybean (Glycine max) planting date on velvetleaf (Abutilon theophrasti) competition. Weed Sci. 27:183188.
14. Oliver, L. R., Frans, R. E., and Talbert, R. E. 1976. Field competition between tall morningglory and soybean. I. Growth analysis. Weed Sci. 24:482487.
15. Orwick, P. L. and Schreiber, M. M. 1979. Interference of redroot pigweed (Amaranthus retroflexus) and robust foxtail (Setaria viridis var. robusta-alba or var. robusta-purpurea) in soybeans (Glycine max). Weed Sci. 27:665674.
16. Potter, J. R. and Jones, J. W. 1977. Leaf area partitioning as an important factor in growth. Plant Physiol. 59:1014.
17. Thurlow, D. L. and Buchanan, G. A. 1972. Competition of sicklepod with soybeans. Weed Sci. 20:379384.
18. Wilson, H. P. and Cole, R. H. 1966. Morningglory competition in soybeans. Weeds. 14:4951.
19. Wyse, D. L. 1980. Vernolate for augmentation of quackgrass (Agropyron repens) control with glyphosate. Weed Sci. 28:654657.


Influence of Quackgrass (Agropyron repens) Density and Duration of Interference on Soybeans (Glycine max)

  • Frank L. Young (a1), Donald L. Wyse (a1) and Robert J. Jones (a1)


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