Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-04T18:26:09.042Z Has data issue: false hasContentIssue false
  • English
  • Français

Decision Criterion for Profitable Johnsongrass (Sorghum halepense) Management in Soybeans (Glycine max)

Published online by Cambridge University Press:  12 June 2017

Roland K. Roberts  and
Robert M. Hayes
Roland K. Roberts
Affiliation:
Dep. Agric. Econ. Rural Soc., Knoxville, TN 37916
Robert M. Hayes
Affiliation:
Dep. Plant Soil Sci., Univ. Tenn., Knoxville, TN 37916
Get access Rights & Permissions [Opens in a new window]

Abstract

A decision criterion is presented for postemergence johnsongrass control in soybeans. Models derived from actual data describing the relationship between johnsongrass density (X) and soybean yield loss are used to develop the decision criterion for soybeans planted in 0.25- and 1-m row spacings. The yield loss equations are L1 = 424–424 exp (-0.023X2) for 0.25-m row spacing and L2 = 643-643 exp (−0.004X2) for 1-m row spacing. When combined with the cost of control (Px) and the expected price of soybeans (Py), these equations can be used to find the density thresholds where johnsongrass control becomes profitable. For the 0.25-m row spacing, this relationship was Px = Py [424–424 exp (−0.023X2) or more simply Px = Py L1, which equates the cost of control to the value of the soybean yield increase from control. The johnsongrass density (X) that satisfies this equality is the threshold (X*) above which control is profitable.

Keywords

Johnsongrass, Sorghum halepense (L). Pers. #3 SORHAsoybeans, Glycine max (L.)Merr.Economic modeleconomic thresholdscontrol thresholdsweed management
Type
Research
Information
Weed Technology , Volume 3 , Issue 1 , March 1989 , pp. 44 - 47
Copyright
Copyright © 1989 by the Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

1. Bridges, D. C., and Chandler, J. M. 1987. Influence of johnsongrass (Sorghum halepense) density and period of competition on cotton yield. Weed Sci. 35:63–67.Google Scholar
2. Elmore, C. D. 1986. Weed survey – southern states. Res. Rep. South. Weed Sci. Soc. 39:136–158.Google Scholar
3. Holm, L. G., Plucknett, D. L., Pancho, J. V., and Herberger, J. P. 1977. The world's worst weeds, distribution and biology. 1st ed. Univ. Press Hawaii, Honolulu. p. 54–55.Google Scholar
4. Horowitz, M. 1973. Competition of Cynodon dactylon, Sorghum halepense, and Cyperus rotundus on cotton and mustard. Exp. Agric. 9:263–273.CrossRefGoogle Scholar
5. Jordan, T. N., Baker, R. S., and Barrentine, W. L. 1978. Comparative toxicity of several dinitroaniline herbicides. Weed Sci. 26:72–75.Google Scholar
6. Lolas, P. C., and Coble, H. D. 1982. Noncompetitive effects of johnsongrass (Sorghum halepense) on soybeans (Glycine max). Weed Sci. 30:589–593.CrossRefGoogle Scholar
7. McWhorter, C. G. and Anderson, J. M. 1981. The technical and economic effects of johnsongrass (Sorghum halepense) control in soybeans (Glycine max). Weed Sci. 29:245–253.Google Scholar
8. McWhorter, C. G., and Hartwig, E. E. 1972. Competition of johnsongrass and cocklebur with six soybean varieties. Weed Sci. 20:56–59.CrossRefGoogle Scholar
9. Williams, C. S., and Hayes, R. M. 1984. Johnsongrass (Sorghum halepense) competition in soybeans (Glycine max). Weed Sci. 32:498–501.CrossRefGoogle Scholar