Submitted to: Weed Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/20/2001
Publication Date: 8/23/2001
Citation: Kolberg, R.L., Wiles, L.J. 2001. Effect of steam application on cropland weeds. Weed Technology. 16(1):43-49. Interpretive Summary: The ability of steam to control common cropland weeds was compared to that of two common herbicides, glyphosate (Roundup), a systematic herbicide and paraquat, a contact herbicide. Weeds tested were common lambsquarters, redroot pigweed, green foxtail, downy brome, and black nightshade. Steam was similar to the herbicides in controlling lambsquarters and pigweed in the seedling stage. Steam was also similar to these herbicides in stunting the growth of green foxtail when applied after the seed head is exposed. Steam applied at two rates (x and 2x) was able to hinder growth of a mixed stand of weeds only at the higher rate (about 35t0 gal./ac). Steam was more effective in reducing growth of downy brome at flowering than at the seedling stage. Steam applied to the top layer of soil with tillage did not affect weed seed germination. In general, young broadleaf weeds were easiest to control using steam.
Technical Abstract: Plot-scale field studies were conducted to evaluate the efficacy of steam for control of cropland weed in comparison with common herbicides. Weed densities, biomass or emergence after treatment was measured. Steam (3200 kg/ha, energy dosage equivalent to 890 kJ/m2, speed of lambsquarters and seedling redroot pigweed. Steam was comparable to glyphosate and paraquat in reducing green foxtail biomass at heading 2 weeks after application. Steam applied at a rate of 3200 kg/ha significantly reduced weed biomass (mixed stand, treated at seedling stage) 9 weeks after application compared to the control, whereas a rate of 1600 kg/ha (1.6 m/s) did not. Biomass of downy brome treated with steam was reduced more at anthesis that at the seedling growth stage. Emergence of common lambquarters, redroot pigweed, and black nightshade was not affected by steam application. Amount of steam applied, weed species, and growth stage are key factors in determining control effectiveness.