WEED POPULATIONS IN CONVENTIONAL AND CONSERVATION TILLAGE MANAGEMENT COTTON AND SOYBEAN SYSTEMS

Authors: Bryson, Charles; HANKS, JAMES - USDA-ARS

Submitted to: Mississippi Agricultural and Forestry Experiment Station Technical Bulletin
Publication Type: Experiment Station
Publication Acceptance Date: 8/25/2003
Publication Date: 5/30/2006
Citation: Bryson, C.T., Hanks, J.E. 2006. Weed populations in conventional and conservation tillage management cotton and soybean systems. Mississippi Agricultural and Forestry Experiment Station Technical Bulletin Vol. 23, No. 18, pp 1-6.

Interpretive Summary: Despite current knowledge and advancements in weed control methods, weed losses exceed $4.1 billion annually in the United States. The Mississippi Delta Management Systems Evaluation Area Project (MSEA) was established to improve water quality and incorporate safe and effective innovative agricultural practices. During a 5-year period, weed population shifts were detected in conservation tillage cotton and soybean. However, at the end of 5-year period, most weed populations were lower than at the initiation of the study in the reduced-tillage cotton and soybean, possibly because a hooded sprayer and genetically manipulated, herbicide-resistant crops were used for weed control. The results are encouraging for farmers because most weed species were effectively controlled despite less tillage. A few woody species (e.g. bigroot morningglory, horsenettle, etc.) populations increased in the reduced-tillage crop areas, regardless of the use of these management technologies.

Technical Abstract: Over a 5-year period, weed population shifts were detected in conservation tillage cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merrill] at the Mississippi Delta Management Systems Evaluation Area Deep Hollow (DH) site near Sidon, MS. Plant populations were monitored to determine plant species composition, population levels, and weed shifts in cropland areas including conventional, conservation tillage, and reduced herbicide management systems. Species composition was determined for non-cropland areas including grass filter strips, field borders, riparian zones, and in and around the watershed lake. The number of weeds and number per species were greater in conservation tillage than in conventional planted cotton and soybean. However, at the end of 5-year period, most weed populations were lower than at the initiation of the study in the reduced-tillage cotton and soybean, except a few woody species (e.g. bigroot morningglory, horsenettle, etc.) that increased in the reduced-tillage crop areas, regardless of the use of these management technologies.