Author
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DONALD, WILLIAM |
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Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/17/2006 Publication Date: 6/1/2007 Citation: Donald, W.W. 2007. Control of both winter annual and summer annual weeds in no-till corn with between-row mowing systems. Weed Technology 21(3):591-601. Interpretive Summary: Throughout the Midwest, persistent herbicides, such as atrazine, can wash off fields in runoff water during storms. Then, this herbicide-laden runoff can contaminate surface and ground water. To minimize the chance of water contamination by herbicides, farmers need effective alternative ways to manage weeds in field crops, such as corn, that reduce herbicide use and are also compatible with soil conservation practices for controlling erosion, such as no-tillage. One way to halve total herbicide use is to reduce the area of fields treated with herbicides by substituting unconventional mechanical weed control for herbicides between rows. In published research in reduced-till soybean and corn, preemergence herbicide use for controlling summer annual weeds was reduced 50% by banding herbicides over crop rows and substituting between-row mowing for cultivation. The research objective was to determine whether such systems could successfully control both winter annual and summer annual weeds in no-till corn as well as broadcast herbicides. To control winter annual weeds before planting no-till corn, glyphosate (i.e., Roundup) was banded over rows and weeds between bands were trimmed close to the soil surface. Then to control summer annual weeds emerging after no-till corn was planted, a soil-active herbicide mixture of atrazine plus s-metolachlor (i.e., Bicep II) was banded over rows followed by mowing between rows when weeds were tall enough to mow. Winter annual weeds growing between rows were controlled with 1 mowing, and summer annual weeds were controlled with either 1 late mowing or 2 mowings (i.e., early and late). In 2 of 3 yrs in Missouri, between-row mowing systems controlled and reduced both winter annual and summer annual weed cover and prevented weeds from reducing corn yields. Such between-row mowing systems successfully controlled weeds, prevented weeds from reducing yields, and can be work in no-till corn. Commercially acceptable corn stands were critical for success of between-row mowing systems. Total herbicide use was reduced 50% (i.e., 25% and 25% for winter annual and summer annual weed control, respectively) in no-till corn. The generic system likely can be used with other banded herbicides. These applied results should interest farmers, extension agents, mower manufacturers, herbicide manufacturers, weed scientists, and environmentalists who wish to minimize herbicide contamination of surface water. Technical Abstract: In previous research, summer annual weeds were successfully controlled in no-till corn with between-row mowing systems that consisted of soil-residual preemergence herbicides banded over corn rows followed by mowing weeds close to the soil surface 1 or 2 times later during the growing season. The research objective was to determine whether between-row mowing systems could successfully control both winter annual and summer annual weeds as well as broadcast herbicides perform in no-till corn. In 2 of 3 yrs in Missouri, between-row mowing systems controlled and reduced both winter annual and summer annual weed cover and prevented weeds from reducing corn yields. Corn yields for the following no-till weed management systems equaled the weed-free check: winter annual weed control with between-row mowing plus preplant, banded, postemergence-applied glyphosate at 1.1 kg ae/ha and later summer annual weed control with postplant, banded, preemergence-applied atrazine plus s-metolachlor at 2.2 plus 1.8 kg ai/ha followed by between-row mowing. Winter annual weeds growing between rows were controlled with 1 mowing, and later summer annual weeds were controlled with either 1 late or "middle" mowing or 2 mowings (i.e., early and late). Total herbicide use was reduced 50% (i.e., 25% and 25%, respectively) in no-till corn. Commercially acceptable corn stands were needed for between-row mowing systems to adequately control weeds. In 1 of 3 yrs when corn stands were half of those of the other 2 yrs, broadcast herbicides performed better than between-row mowing systems in no-till corn. |
