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Weed Science Research Summaries 2011, K. L. Smith, J. A. Bullington, R. C. Doherty, J. R. Meier 2012 University of Arkansas at Monticello

Weed Science Research Summaries 2011, K. L. Smith, J. A. Bullington, R. C. Doherty, J. R. Meier

Arkansas Agricultural Experiment Station Research Series

No abstract provided.


Distribution And Control Of Herbicide-Resistant Italian Ryegrass (Lolium Perenne L. Ssp. Multiflorum Lam. Husnot) In Arkansas, James Walker Dickson 2012 University of Arkansas, Fayetteville

Distribution And Control Of Herbicide-Resistant Italian Ryegrass (Lolium Perenne L. Ssp. Multiflorum Lam. Husnot) In Arkansas, James Walker Dickson

Graduate Theses and Dissertations

Italian ryegrass populations have evolved resistance to herbicides that producers rely on for weed control both in wheat and burn-down. The objectives of this research were to: test populations of Italian ryegrass from across Arkansas for resistance to glyphosate, diclofop, pinoxaden, and pyroxsulam; determine if there were any differences in control of 12 glyphosate-resistant populations in relation to glyphosate rate or application timing; determine the level of glyphosate resistance in one selected population versus a susceptible standard and a previously discovered glyphosate-resistant population; and determine the best options for controlling Italian ryegrass prior to planting crops. A total of 215 ...


Herbicide Resistance Mechanism(S) In Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Populations In The Southern United States, Reiofeli Algodon Salas 2012 University of Arkansas, Fayetteville

Herbicide Resistance Mechanism(S) In Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Populations In The Southern United States, Reiofeli Algodon Salas

Graduate Theses and Dissertations

Italian ryegrass is a principal weed problem in wheat production fields in the Southern US. Resistance to herbicides diclofop, mesosulfuron, and pinoxaden among ryegrass populations has been reported. Glyphosate-resistant Italian ryegrass populations were identified in Desha County, Arkansas. This research aimed to 1) determine resistance patterns to ACCase (diclofop and pinoxaden) and ALS (imazamox, mesosulfuron, and pyroxsulam) herbicides among Italian ryegrass populations from the southern US; 2) determine if cytochrome P450-mediated enhanced herbicide metabolism contributed to resistance; and 3) elucidate the resistance mechanism to glyphosate in four Arkansas populations (Des03, Des05, Des14, and D8). For objective 1, 30 accessions from ...


'Early' Early-Spring Weed Management, Robert G. Hartzler, Micheal D. K. Owen 2012 Iowa State University

'Early' Early-Spring Weed Management, Robert G. Hartzler, Micheal D. K. Owen

Integrated Crop Management News

The unusually warm weather may create additional weed challenges this spring. Winter annuals in no-till fields will likely accumulate much more biomass prior to planting than normal and therefore use more soil moisture, tie up more nutrients and potentially interfere with planting and crop establishment. In addition, weeds such as horseweed (marestail) will grow more rapidly and reach growth stages that are difficult to control much sooner than in a “normal” spring.


Understanding The Biology, Inheritance And Mechanism Of Resistance Of 2,4-D Resistant Waterhemp (Amaranthus Tuberculatus) - Research Proposal, Roberto Crespo 2012 University of Nebraska-Lincoln

Understanding The Biology, Inheritance And Mechanism Of Resistance Of 2,4-D Resistant Waterhemp (Amaranthus Tuberculatus) - Research Proposal, Roberto Crespo

Theses, Dissertations, and Student Research in Agronomy and Horticulture

Waterhemp is a very well adapted summer annual weed to the U.S. Corn Belt region. Auxinic herbicides such as 2,4-D constitute effective and widely used herbicides to control waterhemp and other broadleaf species in cereal crops and turf grasses. Recently, Bernards et al. (2012) have reported a Nebraska waterhemp biotype has evolved resistant to 2,4-D. This finding represents the sixth mode-of action herbicide group to which waterhemp has evolved resistance to. Several attributes may have contributed to make waterhemp a very successful weed and prone to evolve to herbicide resistant: a high genetic variability, aggressive growth habits ...


Herbicide Resistance Meetings, Micheal D. K. Owen, Robert G. Hartzler 2012 Iowa State University

Herbicide Resistance Meetings, Micheal D. K. Owen, Robert G. Hartzler

Integrated Crop Management News

In response to rapidly expanding problems associated with herbicide resistant weeds, ISU Extension and Outreach will conduct a series of meetings in March to address the issue. The meetings will provide information about the causes of herbicide-resistant weed populations, objectively evaluate weed management programs currently used in Iowa, and support the development of durable weed management programs. The meetings will begin at 9 a.m. and conclude with a noon meal.


Superweeds And Suspect Seeds: Does The Genetically-Engineered Crop Deregulation Process Put American Agriculture At Risk, Margaret Sova McCabe 2012 University of New Hampshire School of Law

Superweeds And Suspect Seeds: Does The Genetically-Engineered Crop Deregulation Process Put American Agriculture At Risk, Margaret Sova Mccabe

Law Faculty Scholarship

The federal government’s regulatory approach to genetically engineered (GE) crops, known as “The Framework”, is now twenty-five years old. Despite two and half decades of a consistent regulatory regime, GE crop and food regulation remains controversial. This article suggests that regulatory science and its tenets of independence, transparency, and public science should guide reforms of The Framework so that it is an efficient and reliable regulatory system. The article has four parts: 1) it provides a brief overview of the history of GE crop regulation; 2)it describes the key attributes of The Framework and related regulatory documents, with ...


Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: Iii. Seedling Recruitment Behavior, Kari Jovaag, Jack H. Dekker, Brad Atchison 2012 Iowa State University

Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: Iii. Seedling Recruitment Behavior, Kari Jovaag, Jack H. Dekker, Brad Atchison

Agronomy Publications

Seedling recruitment of heterogeneous Setaria faberi seed entering the soil post-abscission is elucidated herein. This is the third in a series of three articles providing evidence that weedy Setaria seedling recruitment behavior is predicated on dormancy state heterogeneity at abscission (seed heteroblasty), as modulated by environmental signals. Complex oscillating patterns of seedling emergence were observed during the first half of the growing season in all 503 soil burial cores of the 39 populations studied. These patterns were attributed to six distinct dormancy phenotype cohorts arising from inherent somatic polymorphism in seed dormancy states (canalized phenotypes). Early season cohorts were formalized ...


Coexistence Patterns Of Two Invasive Thistle Species, Carduus Nutans And C. Acanthoides, At Three Spatial Scales, Emily S.J. Rauschert, Katriona Shea, Ottar N. Bjørnstad 2012 Cleveland State University

Coexistence Patterns Of Two Invasive Thistle Species, Carduus Nutans And C. Acanthoides, At Three Spatial Scales, Emily S.J. Rauschert, Katriona Shea, Ottar N. Bjørnstad

Biological, Geological, and Environmental Faculty Publications

To better understand the competitive processes involved in invasion by congeners, we examine coexistence patterns of two invasive species, Carduus nutans and C. acanthoides, at three spatial scales. A roadside survey of 5 × 5 km blocks in a previously identified overlap zone provided information about the regional scale. At smaller scales, we surveyed four fields of natural co-occurrence, quantifying the spatial patterns at the field scale by randomly placed 1 × 1 m quadrats and at the smallest scale by detailing plant position within the quadrats. The patterns observed are strikingly different at the different scales. At the regional scale, there ...


The Influence Of Biochar Production On Herbicide Sorption Characteristics, Sharon A. Clay, Douglas D. Malo 2012 South Dakota State University

The Influence Of Biochar Production On Herbicide Sorption Characteristics, Sharon A. Clay, Douglas D. Malo

Agronomy, Horticulture and Plant Science Faculty Publications

Biochar is the by-product of a thermal process conducted under low oxygen or oxygen-free conditions (pyrolysis) to convert vegetative biomass to biofuel (Jha et al., 2010). There are a wide variety of end-products that can be manufactured depending on processing parameters and initial feedstocks (Bridgewater, 2003). The pyrolytic process parameters such as temperature, heating rate, and pressure can change the recovery amounts of each end-product, energy values of the bio-oils, and the physico-chemical properties of biochar (Yaman, 2004).


Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: Ii. Seed Behavior In The Soil, Kari Jovaag, Jack H. Dekker, Brad Atchison 2012 Iowa State University

Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: Ii. Seed Behavior In The Soil, Kari Jovaag, Jack H. Dekker, Brad Atchison

Agronomy Publications

The fate of heteroblastic Setaria faberi seed entering the soil post-abscission is elucidated. Introduction of four populations of S. faberi seeds with heterogeneous dormancy capacities into the soil of a no-till Glycine max field resulted in the formation of enduring pools with varying cycles of dormancy, after-ripening, germination, dormancy reinduction and death. The buried seed rain of these highly dormant seed after-ripened with time and became highly germinable, awaiting favourable temperature and moisture conditions: the heterogeneous germination candidate pool. As this pool was depleted in the spring and early summer by seedling emergence and death, dormancy was re-induced in the ...


Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: I. Seed Dormancy Heterogeneity At Abscission, Kari Jovaag, Jack H. Dekker, Brad Atchison 2012 Iowa State University

Setaria Faberi Seed Heteroblasty Blueprints Seedling Recruitment: I. Seed Dormancy Heterogeneity At Abscission, Kari Jovaag, Jack H. Dekker, Brad Atchison

Agronomy Publications

Studies were conducted to determine the relationship between weedy Setaria faberi seed dormancy and subsequent behaviors in the soil culminating in seedling recruitment.This is the first in a series of three articles demonstrating weedy Setaria seed dormancy capacity heterogeneity at abscission (seed heteroblasty) provides a “blueprint” for those subsequent behaviours. The objective for this present article was to provide a robust characterization of seed heteroblasty at the time of dispersal for 39 locally adapted S. faberi populations, as influenced by parental genotype (time of embryogenesis) and environment (year, location). The heteroblastic structure of each population was revealed by the ...


Csr2- Soil Productivity Rating For Cropland In Iowa, Usa, C. Lee Burras, Rachel K. Owen 2012 Iowa State University

Csr2- Soil Productivity Rating For Cropland In Iowa, Usa, C. Lee Burras, Rachel K. Owen

Agronomy Publications

The Iowa Corn Suitability Rating (CSR2) is a soil productivity rating system used primarily for taxation purposes on cropland in Iowa and is derived from its original version “CSR.” CSR2 was created using seven transparent parameters that allow for efficient calculation.


Weed Identification Guide Available Electronically, Daren S. Mueller 2011 Iowa State University

Weed Identification Guide Available Electronically, Daren S. Mueller

Integrated Crop Management News

The popular Weed Identification Field Guide is now available electronically as an e-book and, for the first time, downloadable on iPad. The publication is distributed by the Iowa Soybean Association (ISA) and Iowa State University (ISU) Extension and Outreach. Pioneer Hi-Bred, a DuPont business, has sponsored the capability for users to download the electronic versions for no charge.


Herbicide-Resistant Weeds: An Evolving Problem Of Importance In Iowa Crop Production, Micheal D. K. Owen 2011 Iowa State University

Herbicide-Resistant Weeds: An Evolving Problem Of Importance In Iowa Crop Production, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

The changes in Iowa agriculture over the last three decades have been monumental and the implications of these changes often overlooked during the course of developing the plans for next year.


Weed Management For 2012, Micheal D. K. Owen 2011 Iowa State University

Weed Management For 2012, Micheal D. K. Owen

Proceedings of the Integrated Crop Management Conference

While there have not been many new things in weed control/management for 2012, some that have occurred are not necessarily good. Herbicide resistance, particularly in common waterhemp has escalated significantly for populations with evolved resistance to glyphosate and resistance to HPPD herbicides has predictably has been identified in a number of locations across Iowa. Unfortunately, again as predicted, no new “silver bullets” have surfaced and in fact, it is unlikely that new herbicide mechanisms of action will be introduced in the foreseeable future. Thus it comes that much more important to recognize the tactics that are available and establish ...


A Reintroduction To Soil Applied Herbicides, Bob Hartzler 2011 Iowa State University

A Reintroduction To Soil Applied Herbicides, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

Although the growth regulator herbicides (2,4-D; dicamba, etc.) were responsible for ushering in the chemical era of weed control in the late 1940’s, it was the introduction of the triazine, dinitroaniline and amide herbicides that transformed weed control in corn and soybean.


Annual Warm-Season Grasses Vary For Forage Yield, Quality, And Competitiveness With Weeds, Andrew W. Lenssen, S. Dennis Cash 2011 United States Department of Agriculture

Annual Warm-Season Grasses Vary For Forage Yield, Quality, And Competitiveness With Weeds, Andrew W. Lenssen, S. Dennis Cash

Andrew W. Lenssen

Warm-season annual grasses may be suitable as forage crops in integrated weed management systems with reduced herbicide use. A 2-year field study was conducted to determine whether tillage system and nitrogen (N) fertilizer application method influenced crop and weed biomass, water use, water use efficiency (WUE), and forage quality of three warm-season grasses, and seed production by associated weeds. Tillage systems were zero tillage and conventional tillage with a field cultivator. The N fertilization methods were urea broadcast or banded near seed rows at planting. Warm-season grasses seeded were foxtail (Setaria italica L.) and proso (Panicum mileaceum L.) millets, and ...


Review Of Teaching Children Science: Hands-On Nature Study In North America, 1890-1930 By Sally Kohlstedt, Meena M. Balgopal 2011 Colorado State University - Fort Collins

Review Of Teaching Children Science: Hands-On Nature Study In North America, 1890-1930 By Sally Kohlstedt, Meena M. Balgopal

The Prairie Naturalist

Many scientists and educators agree that the goal of science education is to prepare students "to know, use and interpret scientific explanations of the natural world," as cited in the National Research Council publication, Taking Science to School: Learning and Teaching Science in Grades K-8 (DuschI et al. 2007). Yet, many science instructors of K-12 and post-secondary students often rely on teacher-telling modes of pedagogy and neglect to engage their students in natural inquiry and scientific study that model the research methods used by scientists. As a result, many young people are not aware of how scientists make discoveries about ...


Modeling Parental Provisioning By Red-Winged Blackbirds In North Dakota, George M. Linz, Richard S. Sawin, Mark W. Lutman, William J. Bleier 2011 Wildlife Services, National Wildlife Research Center

Modeling Parental Provisioning By Red-Winged Blackbirds In North Dakota, George M. Linz, Richard S. Sawin, Mark W. Lutman, William J. Bleier

The Prairie Naturalist

Male red-winged blackbirds (Agelaius phoeniceus) exhibit a difference in nest provisioning rates along an east-west gradient in North America. North Dakota is located in the center of North America and harbors a large population of breeding red-winged blackbirds (RWBL). This location provided an opportunity to compare provisioning rates in the central U.S. with those reported for the eastern and western populations. We placed video cameras at RWBL nests to record male and female feeding trips. Thirty-four nests were located on territories with original males and 30 were on territories where a replacement (floater) male had taken over a territory ...


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