DEEP TILLAGE AND GLYPHOSATE REDUCED REDVINE AND TRUMPETCREEPER POPULATIONS IN ROUNDUP READY SOYBEAN

Authors: Reddy, Krishna

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 1/26/2004
Publication Date: 1/26/2004
Citation: Reddy, K.N. 2004. Deep tillage and glyphosate reduced redvine and trumpetcreeper populations in roundup ready soybean. Proceedings of Southern Weed Science Society.

Interpretive Summary:

Technical Abstract: Redvine [Brunnichia ovata (Walt.) Shinners] and trumpetcreeper [Campsis radicans (L.) Seem. ex Bureau] are deciduous perennial woody vines distributed extensively in the Mississippi Delta. These vines have an extensive, deep-rooted system, which enables them to spread and survive environmental extremes. They are among the 10 most troublesome weeds in row crops of the mid-southern U.S. As herbicides alone cannot provide complete control of these vines, additional management tactics are needed. This study examines integration of deep tillage and glyphosate for management of redvine and trumpetcreeper in Roundup Ready soybean. A 3-yr field study was conducted during 2000-2002 on a Dundee silty clay loam at Stoneville, MS. The experiment was conducted in a split-split plot arrangement of treatments in a randomized complete block design with tillage as main plot, preplant application of glyphosate as subplot, and in-crop glyphosate postemergence (POST) as sub-subplot with four replications. Deep tillage for 1, 2, and 3 years consecutively decreased redvine density by 95, 88, and 97%, respectively, compared with shallow tillage, but deep tillage had no effect on trumpetcreeper density. Glyphosate applied preplant reduced trumpetcreeper density (25 to 44%), but not redvine compared with no glyphosate in all three years. Glyphosate EPOST alone (45 to 67%) or followed by LPOST (59 to 83%) reduced density of trumpetcreeper but not redvine compared with no herbicide. However, dry biomass of redvine was reduced with glyphosate in-crop POST compared with no herbicide. Soybean yields were higher with deep tillage vs. shallow tillage, glyphosate preplant application vs. no glyphosate, and glyphosate EPOST alone or followed by glyphosate LPOST vs. no herbicide. These results show that deep tillage even for one year could effectively reduce redvine density. Glyphosate preplant, EPOST, and EPOST followed by LPOST applications could greatly reduce trumpetcreeper density and suppress growth of redvine in Roundup Ready soybean.