Life Sciences Commons^™

A Comparison Of Drinking Water Contamination In Buried Slab Wells, Other Large-Diameter Wells, And Drilled Wells, Rita M. Gergely

Journal of the Iowa Academy of Science: JIAS

This study presents the results of a statewide water well survey conducted by the Iowa Department of Public Health from 1993 to 1995 to determine whether there were statistically significant differences between well water contamination in buried slab wells, other large-diameter wells, and drilled wells. Wells were sampled for total coliform bacteria, fecal coliform bacteria, nitrate, and atrazine. Staff collected water samples and completed a site survey at each well, which included an interview with the occupant or owner and actual observations of the wellhead and surrounding area.

The study included 293 buried slab wells, 287 other large-diameter wells, and …

Nf02-503 Atrazine And Non-Atrazine Herbicide Comparisons In Conventional Till Corn, Fred Roeth, Alex Martin

University of Nebraska-Lincoln Extension: Historical Materials

Atrazine herbicide has been in an EPA special review since 1994 because of surface and groundwater contamination concerns. Beginning in 1997, we evaluated atrazine and non-atrazine herbicides in conventional tillage corn and no-till corn on university research farms at Clay Center and Lincoln, Nebraska. The objective was to compare some common atrazine and non-atrazine herbicides for weed control and crop response. Thirteen herbicides were selected to represent commonly used herbicide classes and treatment timings. This NebFact reports the conventional till results.

Nf02-504 Atrazine And Non-Atrazine Herbicide Comparisons In No-Till Corn, Fred Roeth, Alex Martin

University of Nebraska-Lincoln Extension: Historical Materials

Atrazine herbicide has been in an EPA special review since 1994 because of soil surface runoff concerns. Beginning in 1997, we evaluated atrazine and non-atrazine herbicide treatments in conventional tillage corn and no-till corn on university research farms at Clay Center (irrigated) and Lincoln, Nebraska (non-irrigated). The objective was to compare some common atrazine and non-atrazine herbicides in soil-applied and post emergence treatment combinations. Fourteen herbicide treatments were selected to represent commonly used herbicide classes and application timings. This NebFact reports the no-till results.

Atrazine And Non-Atrazine Herbicide Comparisons In Conventional Till Corn, Fred Roeth, Alex Martin

University of Nebraska-Lincoln Extension: Historical Materials

Sequential herbicide applications (preemergence followed by postemergence) were more consistent in weed control across four environments because the postemergence treatments controlled weed escapes and second flushes. Singular herbicide treatments were less effective in that regard. Several single applications gave good control but not the excellent control of the sequential treatments. Atrazine in the preemergence application failed to control velvetleaf, but provided good control when used postemergence. The non-atrazine herbicides were at least as effective as the atrazine herbicides.

Atrazine And Non-Atrazine Herbicide Comparisons In No-Till Corn, Fred Roeth, Alex Martin

University of Nebraska-Lincoln Extension: Historical Materials

Although not all herbicides were completely effective in this study, various ones performed well, including atrazine and non-atrazine treatments. The atrazine treatments cost less than most other treatments. The sequential application strategy was consistently better than a single application because the postemergence followup treatment controlled the escapes and second flushes. Single treatments were at a disadvantage in that regard; however, several preemergence, non-atrazine herbicide treatments were noteworthy in their performance.

Interactive Effects Of Anthropogenic, Environmental, And Biotic Stressors On Multiple Endpoints In Hyla Chrysoscelis, Carol A. Britson, Stephen T. Threlkeld

Journal of the Iowa Academy of Science: JIAS

Multiple stressors have been proposed as causative agents for declining populations and increased incidence of malformations in amphibians although few studies have examined possible interactions among these stressors. We measured interactive effects of UV radiation, three chemicals, and interspecific competition (with Rana 1phenocephala) on multiple endpoints in Hyla chrysoscelis using a center point- and chemical-free control-enhanced 2⁴ factorial design. UV radiation was transmitted or filtered using OP-4 or OP-3 acrylite filters installed above 72, 500-liter mesocosms on 16 May 1997. Methyl mercury, chlorpyrifos, and atrazine were applied at levels of 0, 10, 50, and 100 % of 400 ppb, …

Nf98-362 Chemical Weed Control In Tree Planting Projects: Part I - Pre-Emergence Herbicides, John Duplissis

University of Nebraska-Lincoln Extension: Historical Materials

This NebFact examines weed control in tree planting projects.

G96-1299 Agricultural Management Practices To Reduce Atrazine In Surface Water, Thomas G. Franti, Fred Roeth, Robert N. Klein, David L. Holshouser, Andrew P. Christiansen, James A. Schild, Gary L. Zoubek

University of Nebraska-Lincoln Extension: Historical Materials

Ways to reduce atrazine availability, reduce the amount of water runoff, and reduce the impact of the first runoff are covered here. Each year growers face many decisions when planning for a new growing season, including selection of an economical weed control program. Because of their ease of use and effectiveness, many producers use preemergence herbicides to control weeds. Because of its low cost, corn and sorghum growers often select atrazine or an atrazine combination. Nebraska corn growers annually apply an estimated 6.3 million pounds of atrazine. Atrazine is an effective and low-cost herbicide, but there is a hidden cost …

Nf93-120 The 1993 Atrazine Label Revision, Fred W. Roeth

University of Nebraska-Lincoln Extension: Historical Materials

This NebFact discusses the 1993 label revision of Atrazine.

G93-1158 Questions And Answers About Atrazine, Fred Roeth, S.D. Comfort

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide addresses some of the current concerns about atrazine and water quality. Included are some questions and answers about atrazine regarding toxicity, EPA guidelines, presence in water supplies, weed resistance and best management practices. What is atrazine? Atrazine is a herbicide that selectively controls broadleaf (dicot) weeds, such as pigweed, cocklebur, velvetleaf and certain grass weeds in fields of corn and sorghum. Selective control means that the target weeds are controlled, with little or no injury to the crop. Atrazine is well tolerated by actively growing corn and sorghum, which absorb and metabolize the herbicide and thereby detoxify it.

Mutant Weeds Of Iowa: V. S-Triazine Resistant Setaria Faberi Herrm, R. Thornhill, J. Dekker

Journal of the Iowa Academy of Science: JIAS

S-triazine resistance in giant foxtail (Setaria faberi Herrm.) has been reported previously, but not in the midwestern U.S. corn belt or Iowa. A study was conducted using a chlorophyll fluorescence assay to confirm the presence of resistance in one S. faberi population in Iowa. Variable chlorophyll fluorescence assays confirmed that a population of this species with this type of resistance exists in Iowa. This is the first report of s-triazine resistance in S. faberi, and the fourth species with this type of herbicide resistance, found in an Iowa agroecosystem.

Mutant Weeds Of Iowa: S-Triazine-Resistant Plastids Chenopodium Album L., Jack Dekker, Ronald Burmester

Journal of the Iowa Academy of Science: JIAS

S-triazine resistance in common lambsquarters (Chenopodium album L.) has been reported previously but not in Iowa. A study was conducted using a chlorophyll a fluorescence assay to confirm the presence of resistance in C. album populations in Iowa. Variable chlorophyll a fluorescence assays confirmed that mutations conferring resistance exist in five (5) geographically separated populations of C. album in Iowa: relatively greater fluorescence yields were measured in untreated resistant tissue compared with untreated susceptible plants, relatively greater fluorescence yield in treated compared with untreated susceptible leaf disks; and similar fluorescence yields of treated and untreated resistant tissue. This is the …