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Articles 1 - 8 of 8

Full-Text Articles in Life Sciences

Evaluation Of Prairie Grasses For Reducing The Environmental Impact Of Herbicide Contamination , Jason B. Belden Jan 2003

Evaluation Of Prairie Grasses For Reducing The Environmental Impact Of Herbicide Contamination , Jason B. Belden

Retrospective Theses and Dissertations

The primary goal of this dissertation was to evaluate the use of prairie grasses for reducing the environmental impact of herbicides. Studies included: use of prairie grasses as a phytoremediation tool for contaminated soil; comparison of grass species for use in vegetative buffer strips; fate of 14C-pendimethalin in vegetated and unvegetated soil; and environmental hazards of pendimethalin contaminated soil.;Throughout this dissertation, evidence was presented that prairie grasses can increase the dissipation rate of herbicides. In one study, 78% less metolachlor and 39% less pendimethalin remaining in vegetated treatments as compared to unvegetated treatments. In a separate study, the presence ...


A Biophysical And Socio-Economic Examination Of The Use Of Shelterbelts For Swine Odor Mitigation , John Charles Tyndall Jan 2003

A Biophysical And Socio-Economic Examination Of The Use Of Shelterbelts For Swine Odor Mitigation , John Charles Tyndall

Retrospective Theses and Dissertations

The use of shelterbelts (trees and shrubs) arranged in strategic designs near and within swine facilities potentially can play a significant incremental role in bio-physically mitigating odor in a socio-economically responsible way thereby reducing social conflict from odor nuisance. Shelterbelts of modest heights (i.e. 20--30 ft) may be ideal for plume interception, disruption, and dilution. Based on available evidence, there are five primary ways that shelterbelts can mitigate livestock odors: (1) Physical interception and capture of odor laden dust by trees/shrubs; (2) Dilution of gas concentrations of odor into the lower atmosphere; (3) Ground deposition of odor laden ...


Spatial And Temporal Scales Of Distribution And Demography In Breeding Songbirds: Implications Of Habitat Fragmentation And Restoration , Robert J. Fletcher Jr. Jan 2003

Spatial And Temporal Scales Of Distribution And Demography In Breeding Songbirds: Implications Of Habitat Fragmentation And Restoration , Robert J. Fletcher Jr.

Retrospective Theses and Dissertations

Tallgrass prairie has declined throughout the midwestern United States during the past two centuries, and migratory birds breeding in these habitats have also experienced precipitous population declines. One conservation strategy used to mitigate the effects of habitat loss and fragmentation is habitat restoration. I studied how both habitat fragmentation and restoration affect songbird populations breeding in grassland and wetland habitats in northern Iowa, 1999--2002. Most grassland birds tended to be less abundant near edges, yet birds avoided woodland edges more so than other types of edges. Edge avoidance could not be explained by changes in habitat structure. For Bobolinks (Dolichonyx ...


Studies Of Solute Transport Through Fractured Till In Iowa , Martin Frederick Helmke Jan 2003

Studies Of Solute Transport Through Fractured Till In Iowa , Martin Frederick Helmke

Retrospective Theses and Dissertations

Fractures may provide pathways for agricultural chemicals to reach aquifers through till units that have traditionally been considered effective barriers to contaminant transport. Till units were studied at three sites in Iowa that represented three landform regions, till ages from 12.5 to >730 ka, and depths from 1 to 27.5 m. Fractures were present at all study locations and at all depths, including one site where fractures intersected an aquifer at 30 m depth. Laboratory experiments using eight large (0.40 to 0.45 m in length and 0.43 m in diameter), undisturbed columns of till showed ...


The Fate Of Phosphorus And Molybdenum After Biosolids, Swine Manure And Triple Superphosphate Were Applied To A Soil , Jorge David Hernandez Jan 2003

The Fate Of Phosphorus And Molybdenum After Biosolids, Swine Manure And Triple Superphosphate Were Applied To A Soil , Jorge David Hernandez

Retrospective Theses and Dissertations

The possible effects of the application of swine manure and biosolids to high phosphorus (P) test soils has been widely debated due to the potential increase in P pollution. The application of these materials to soils might result in changes in water, soil, and crop quality. Increasing P in an already high soil P test (STP) soil may result in changing P dynamics in agro-ecosystems and enhancing P movement away from sorption sites. The purpose of this study was to determine the effect of swine manure (SM), biosolid (BS) and triple superphosphate (TSP) applications on the soil P content in ...


Corn Rootworms (Coleoptera: Chrysomelidae) In Space And Time , Yong-Lak Park Jan 2003

Corn Rootworms (Coleoptera: Chrysomelidae) In Space And Time , Yong-Lak Park

Retrospective Theses and Dissertations

Spatial dispersion is a main characteristic of insect populations. Dispersion pattern provides useful information for developing effective sampling and scouting programs because it affects sampling accuracy, efficiency, and precision. Insect dispersion, however, is dynamic in space and time and largely dependent upon interactions among insect, plant and environmental factors. This study investigated the spatial and temporal dynamics of corn rootworm dispersion at different spatial scales by using the global positioning system, the geographic information system, and geoStatistics and Probability; Egg dispersion pattern was random or uniform in 8-ha cornfields, but could be aggregated at a smaller scale. Larval dispersion pattern ...


Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr. Jan 2003

Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr.

Retrospective Theses and Dissertations

Genotypes with enhanced rooting ability are crucial for deployment of intensively cultured Populus plantations. Rooting of dormant, unrooted cuttings is the first biological prerequisite to stand establishment. The primary objective was evaluating three developmental systems affected by site conditions: lateral and adventitious root ontogenies, root/shoot growth rates, and temperature dependent physiologies. The study tested rooting ability of 21 clones from five taxonomic backgrounds ((Populus deltoides x Populus trichocarpa) x P. deltoides 'BC1'; P. deltoides 'D'; P. deltoides x Populus maximowiczii 'DM'; P. deltoides x Populus nigra 'DN'; P. nigra x P. maximowiczii 'NM') at Ames, Iowa; Waseca, Minnesota; and ...


Factors Affecting Symbolic And Use Adoption Of Local Foods For Consumers In Black Hawk County, Iowa, Erin M. Tegtmeier Jan 2003

Factors Affecting Symbolic And Use Adoption Of Local Foods For Consumers In Black Hawk County, Iowa, Erin M. Tegtmeier

Retrospective Theses and Dissertations

A local food system may be an alternative to the increasingly globalized and concentrated food market and a means to augment the availability of fresh foods, create economically viable options for farmers and enhance the health of local ecosystems. Consumers are a vital component of these systems. Insight into the decision-making process surrounding the purchase of local foods can aid in efforts to build thriving local food systems. Studies on consumer attitudes show that, in general, consumers are aware and supportive of local foods. Abstract or civic factors, such as concern for the environment or food safety, are often identified ...