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Full-Text Articles in Population Biology

Winter Cover Crop Impacts On Weed Dynamics In Eastern And Central Nebraska, Elizabeth Ann Oys Apr 2022

Winter Cover Crop Impacts On Weed Dynamics In Eastern And Central Nebraska, Elizabeth Ann Oys

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Reducing tillage in cropping systems causes weed management to be dependent on chemical and cultural methods for weed control. Over time, herbicide-resistant weeds have developed due to the continuous selection pressures from herbicides, particularly in the Midwest Corn Belt. Integrated weed management strategies, such as cover crops, can be used to mitigate some of these issues. Cover crops are primarily known for their soil health benefits, but there is evidence that cover crops can suppress weeds. However, less research has been done at the field-scale level to address cover crop impacts on the weed seedbank and aboveground weeds during the …


Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo Jul 2011

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …


Biology, Systematics, Phylogenetic Analysis And Dna Character-Based Species Diagnosis Of The False Root-Knot Nematode Nacobbus Aberrans (Thorne, 1935) Thorne & Allen 1944 (Nemata:Pratylenchidae), Angel Ramirez-Suarez Jun 2011

Biology, Systematics, Phylogenetic Analysis And Dna Character-Based Species Diagnosis Of The False Root-Knot Nematode Nacobbus Aberrans (Thorne, 1935) Thorne & Allen 1944 (Nemata:Pratylenchidae), Angel Ramirez-Suarez

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The False Root-Knot nematode Nacobbus aberrans is a plant parasitic nematode that causes yield losses in several crops and plant protection agencies have established regulations to prevent infestations from spreading to new agricultural areas. The taxonomic status of the nematode has been the subject of controversy due to wide degree of variation exhibited by the species. This variability has led to the suggestion that N. aberrans is actually a species complex rather than a single species. In order to test this hypothesis, we compared twelve N. aberrans populations, which include isolates from western Nebraska, two distinct regions of Mexico and …


Demographics And Habitat Selection For The Western Meadowlark (Sturnella Neglecta) In The Nebraska Sandhills, Matthew D. Giovanni Jan 2009

Demographics And Habitat Selection For The Western Meadowlark (Sturnella Neglecta) In The Nebraska Sandhills, Matthew D. Giovanni

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

The prairie ecosystems of the Great Plains region in North America have largely been replaced and fragmented with industrial agriculture and invasive herbaceous and woody plant species. The concurrent and large-scale suppression of wildfire and elimination of grazing by native ungulates may have further decreased the availability and quality of habitat for wildlife. Indeed, 2004 estimates indicate only 30% of historic grasslands in the Great Plains still exist, while the trends of decreased land area enrolled in the Conservation Reserve Program and increased land area in commercial agriculture indicate continued loss of habitat. This decrease in habitat availability continues to …