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item Bryson, Charles
item Hanks, James

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2000
Publication Date: 1/20/2001
Citation: Bryson, C.T., Hanks, J.E. Weed population shifts in the mississippi delta management systems evaluation area. 2001 Proceedings of Southern Weed Science Society. 54:192-193.

Interpretive Summary:

Technical Abstract: The Mississippi Delta Management Systems Evaluation Area (MSEA) was established as a consortium of several federal, state and local agencies to improve water quality and incorporate safe and effective innovative agricultural management systems. At Deep Hollow, Leflore County, MS, one of the MSEA sites, the use of a hooded sensor-controlled sprayer provided excellent weed control, reduced herbicide usage significantly, improved water quality, and increased farmer profits without adversely affecting crop yields. A total of 195 plant species (58 monocots and 137 dicots) were present in croplands (cotton and soybean) at Deep Hollow; however, only 76 species (24 monocots and 52 dicots) were present in both cotton and soybean. In cropland areas, 29 species (2 monocots and 27 dicots) were detected in cotton exclusively, while 90 species (32 monocots and 58 dicots) were present in soybean exclusively. Thus, more plant species were detected in soybean (166 species) than in cotton (105 species). Of the 195 plant species detected in reduced-tillage cotton and soybeans at Deep Hollow, only 25 to 30 were considered troublesome weed problems. Over a 5-yr period, the number of weed species in reduced-tillage was 3- to 4-fold greater than weedy species in conventional planted cotton and soybeans, respectively. Four types of weed shifts were detected in reduced tillage and transgenic crop production systems at the Deep Hollow: 1) populations decreased in cotton and soybean; (2) populations increased in cotton and soybean; 3) populations increased initially and then decreased; and 4) populations increased in one crop while remaining constant or decreasing in the other crop.