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The effect of selected herbicides on CO2 assimilation, chlorophyll fluorescence, and stomatal conductance in johnsongrass (Sorghum halepense L)

Published online by Cambridge University Press:  20 January 2017

Jason A. Ferrell
Affiliation:
Department of Crop and Soil Sciences, University of Georgia, Athens, GA 30602
Hugh J. Earl
Affiliation:
Department of Crop and Soil Sciences, University of Georgia, Athens, GA 30602

Abstract

Greenhouse studies were initiated to determine the duration of time after herbicide treatment required to render johnsongrass physiologically noncompetitive. Nicosulfuron, imazapic, clethodim, and glyphosate were applied to rhizomatous johnsongrass at 35, 70, 140, and 840 g ai ha−1, respectively. Net carbon assimilation, stomatal conductance, chlorophyll meter readings, and maximum (dark adapted) efficiency of photosystem II were measured. Net carbon assimilation (A N) was assumed to be the best indicator of johnsongrass competitiveness. Johnsongrass was considered to be physiologically noncompetitive when A N declined below 50% of that of nontreated check. From these data, it was concluded that glyphosate rendered johnsongrass noncompetitive most readily, 4.3 d after treatment, whereas no differences were detected between nicosulfuron, imazapic, or clethodim throughout the experiment. Stomatal conductance (g s) was highly correlated to A N and was determined to be an adequate substitute for A N when determining johnsongrass competitiveness. It was concluded that chlorophyll meter readings and photosystem II efficiency were poor indicators of johnsongrass competitiveness.

Type
Research Article
Copyright
Copyright © Weed Science Society of America 

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References

Literature Cited

Ahrens, W. H. 1994. Herbicide Handbook. 7th ed. Champaign, IL: Weed Science Society of America. 62 p.Google Scholar
Banks, P. A. and Bundschuh, S. A. 1989. Johnsongrass control in conventionally tilled and no-tilled soybean with foliar-applied herbicides. Agron. J. 81:757760.CrossRefGoogle Scholar
Banks, P. A. and Santelmann, P. W. 1977. Glyphosate as a postemergence treatment for johnsongrass control in cotton and soybeans. Agron. J. 69:579582.CrossRefGoogle Scholar
Banks, P. A. and Tripp, T. N. 1983. Control of johnsongrass (Sorghum halepense) in soybeans (Glycine max) with foliar-applied herbicides. Weed Sci. 31:628633.Google Scholar
Brecke, B. J. and Duke, W. B. 1980. Effects of glyphosate on intact bean plants (Phaseolus vulgaris L.) and isolated cells. Plant Physiol. 66:656659.Google Scholar
Dowler, C. C. 1999. Weed survey—southern states. Proc. South. Weed Sci. Soc. 52:281318.Google Scholar
Hall, M. R., Swanton, C. J., and Anderson, G. W. 1992. The critical period of weed control in grain corn. Weed Sci. 40:441447.Google Scholar
Hicks, R. D. and Fletchall, O. H. 1976. Control of johnsongrass in corn. Weeds 15:1620.CrossRefGoogle Scholar
Johnson, W. G. and Frans, R. E. 1991. Johnsongrass (Sorghum halepense) control in soybeans (Glycine max) with postemergence herbicides. Weed Technol. 5:8791.Google Scholar
Keeley, P. E. and Thullen, R. J. 1989. Growth and interaction of johnsongrass (Sorghum halepense) with cotton (Gossypium hirsutum). Weed Sci. 37:339344.Google Scholar
Marquard, R. D. and Tipton, J. L. 1987. Relationship between extractable chlorophyll and an in situ method to estimate leaf greenness. Hortscience 22:1327.Google Scholar
McWhorter, C. G. 1989. History, biology, and control of johnsongrass. Rev. Weed Sci. 4:85121.Google Scholar
McWhorter, C. G. and Hartwig, E. E. 1972. Competition of johnsongrass and cocklebur with six soybean varieties. Weed Sci. 20:5659.Google Scholar
Monje, O. A. and Bugbee, B. 1992. Inherent limitations of nondestructive chlorophyll meters: a comparison of two types of meters. Hortscience 27:6971.Google Scholar
Obrigawitch, T. T., Kenyon, W. H., and Kuratle, H. 1990. Effect of application timing on rhizome johnsongrass (Sorghum halepense) control with DPX-V9360. Weed Sci. 38:4549.Google Scholar
Parochetti, J. V., Wilson, H. P., and Burt, G. W. 1975. Activity of glyphosate on johnsongrass. Weed Sci. 23:395400.Google Scholar
Perry, K. M., Evans, R., and Jeffery, L. S. 1983. Competition between johnsongrass (Sorghum halepense) and corn (Zea mays). Proc. South. Weed Sci. Soc. 36:345.Google Scholar
Taylor, J. M. and Coats, G. E. 1999. Comparison of johnsongrass weed control programs applied before or after mowing in highway rightsof-ways. Proc. South. Weed Sci. Soc. 52:151152.Google Scholar
Wilcut, J. W., Richburg, J. S. III, and Walls, F. R. Jr. 1999. Response of johnsongrass and imidazolinone-resistant corn to AC 263,222. Weed Technol. 13:484488.CrossRefGoogle Scholar