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Biochemical Aspects Of The Thermal Sensitivity And Energy Balance Of Polar, Tropical And Subtropical Teleosts, Eloy Martinez Jan 2013

Biochemical Aspects Of The Thermal Sensitivity And Energy Balance Of Polar, Tropical And Subtropical Teleosts, Eloy Martinez

Graduate Theses and Dissertations

The maintenance of a functional energy balance in ectothermic fauna could be challenging in a thermally disparate environment. Biochemical adaptations at the enzyme and membrane levels allows for a set compensatory mechanism that allow the individual to maintain an energetic surplus, thus allocating energy for growth and reproduction. The present work describes how the energetic machinery in the cell, particularly the mitochondrion, could be affected by temperature changes. More specifically, this work aimed to determine how environmental temperature affects the mitochondria energetic performance of fishes from disparate thermal regimes.

Mitochondrial ATP production efficiency was evaluated in fishes from polar, tropical ...


Correction For Rapid-Growth Vegetation And Testing Of An Upscaling Method With A Cosmos Probe, Samantha Lou Irvin Jan 2013

Correction For Rapid-Growth Vegetation And Testing Of An Upscaling Method With A Cosmos Probe, Samantha Lou Irvin

Graduate Theses and Dissertations

COSMOS (COsmic-ray Soil Moisture Observing System) probes are a developing instrument in the field of remote sensing and are currently the only source of field scale soil moisture data. A COSMOS probe is essentially a hydrogen particle counter with a measurement depth ranging from 10-70 cm and a spatial resolution approaching 700 m in diameter. A majority of the hydrogen detected is in the form of water molecules. As vegetation contains both hydrogen in the vegetative dry matter and water, in addition to sitting above the ground, it may influence what is measured by the COSMOS probe as soil moisture ...


An Analysis Of Technical Assistance Providers In Copanch'orti' Guatemala, Victoria Lebeaux Jan 2013

An Analysis Of Technical Assistance Providers In Copanch'orti' Guatemala, Victoria Lebeaux

Graduate Theses and Dissertations

Guatemala has the fourth highest rate of chronic under-nutrition for children under five in the world. One region particularly impacted is the Copanch'orti' area of eastern Guatemala where chronic under-nutrition affected 61% of the population in 2008. Although efforts to solve the malnutrition problem have been underway for several decades, there is a persistent need for greater and better coordination and integration of food security programming, within and across sectors (agriculture, education, environment, health, etc.), as well as across local, regional, and national platforms. In this dissertation I addressed the question of how the actions of development practitioners can ...


Analysis Of Sugars And Phenolic Compounds In Bio-Oil, Marjorie Ruth Rover Jan 2013

Analysis Of Sugars And Phenolic Compounds In Bio-Oil, Marjorie Ruth Rover

Graduate Theses and Dissertations

The overall goal of this research is to develop methods for analyzing and recovering sugars and phenolic compounds from bio-oil. Specific objectives include (1) adapting analytical methods developed for sugar analysis in the food industry to measure total water-soluble sugars in the aqueous phase of bio-oil; (2) adapting analytical methods developed for total phenolic analysis of wine to measure total phenolic content of bio-oil; (3) separate the heavy fraction of bio-oil into a concentrated sugar solution and a phenolic oligomer-rich raffinate; and (4) determine the effect of pyrolysis temperature on the yield of sugars and phenolic compounds in bio-oil.

Recent ...


Anthropogenic Eutrophication And Ecosystem Functioning In Freshwater Lakes, Adam John Heathcote Jan 2013

Anthropogenic Eutrophication And Ecosystem Functioning In Freshwater Lakes, Adam John Heathcote

Graduate Theses and Dissertations

Theory predicts that ecosystems under stress change in their structure and functioning and these alterations may be symptomatic of potential breakdown in overall ecosystem functioning due to homeostatic regulation. In this dissertation, I present four studies looking at how ecosystem functioning in thirty-two freshwater lakes changes as a result of stress from anthropogenic eutrophication using paleolimnological and contemporary sampling techniques. In particular these studies looks at the changes to algae (diatom) community structure and production, organic carbon (OC) cycling, importance of external inputs of eroded sediment and nutrients, and resource use efficiency (RUE) of zooplankton. I found significant changes in ...


Techno-Economic Analysis And Life Cycle Assessment Of The Corn Stover Biomass Feedstock Supply Chain System For A Midwest-Based First-Generation Cellulosic Biorefinery, Ajay Shah Jan 2013

Techno-Economic Analysis And Life Cycle Assessment Of The Corn Stover Biomass Feedstock Supply Chain System For A Midwest-Based First-Generation Cellulosic Biorefinery, Ajay Shah

Graduate Theses and Dissertations

Corn stover is the primary feedstock choice for most of the first-generation cellulosic biorefineries in the Midwest, and their rated capacities are in between 76 and 114 million liters per year (MLPY) (i.e., 20 and 30 million gallons per year (MGPY)). For the uninterrupted operation of these plants, a year-round supply of corn stover needs to be secured, which will require a robust, efficient, cost-effective and environmentally-balanced feedstock supply chain. However, there is limited techno-economic and environmental know-how in this area. Thus, the main objective of this dissertation is to stochastically analyze the technoeconomics, life-cycle energy use, and greenhouse ...


White-Faced Capuchins (Cebus Capucinus) Of Cahuita National Park, Costa Rica: Human Foods And Human Interactions, Jennifer Christine Campbell Jan 2013

White-Faced Capuchins (Cebus Capucinus) Of Cahuita National Park, Costa Rica: Human Foods And Human Interactions, Jennifer Christine Campbell

Graduate Theses and Dissertations

Cahuita National Park is an ecotourist destination in southeast Costa Rica. A troop of white-faced capuchins (Cebus capucinus) living in the park was reported by park officials as being problematic due to their food-raiding behavior. In May-June 2012 and again in December 2012-January 2013 I collected behavioral information in the form of scan samples and human-monkey interactions to assess the frequency and severity of these interactions. Type of food consumed was also noted, as consumption of human foods has been shown to cause both demographic and behavioral changes in non-human primate populations. Anthropogenic food sources accounted for 18% for the ...


Development Of Strategies For Synthesis Of Branched Caenorhabditis Elegans-Associated Oligosaccharides And Of Photo-Activated Lectin Capture Reagents, Randy Alan Benedict Jan 2013

Development Of Strategies For Synthesis Of Branched Caenorhabditis Elegans-Associated Oligosaccharides And Of Photo-Activated Lectin Capture Reagents, Randy Alan Benedict

Graduate Theses and Dissertations

The development and investigation of a new affinity proteomics probe and methodology are presented in this dissertation. A trifunctional affinity proteomics probe (TAPP) was envisioned and prepared to serve as a lectin capture reagent. The TAPP consists of a solid support to serve as a handle for captured protein as well as scaffold for multivalency, a saccharide of interest to fish for an unknown or elicit a suspected specific interaction, and a photoactivated cross-linking moiety to covalently capture binding proteins. The perfluorinated phenylazide cross-linker was shown to exhibit better performance relative to the parent phenylazide with respect to sensitivity and ...


Sustainable Chemistry, Synthesis And Structure-Activity Relationship Studies Of Biologically Important Small Molecules, Gerald R. Pollock, Iii Jan 2013

Sustainable Chemistry, Synthesis And Structure-Activity Relationship Studies Of Biologically Important Small Molecules, Gerald R. Pollock, Iii

Graduate Theses and Dissertations

With growing concerns for the environment, dwindling amounts of fossil fuels available for worldwide consumption and more resistant strains of diseases and infections becoming a reality, organic chemistry plays a vital role in the improvement and sustainability of modern society. Industrial chemicals from renewable sources has become an important area of research in recent years, while the synthesis and study of biologically active small molecules and their analogues leads to advancements which can help improve overall human health.

In this dissertation, we explore methods to create important industrial molecules from biorenewable sources, extend a novel cyclization to make heterocyclic compounds ...


Net Effects Of Batrachochytrium Dendrobatidis (Bd) And Fungicides On Anurans Across Life Stages, Jenise Brown Jan 2013

Net Effects Of Batrachochytrium Dendrobatidis (Bd) And Fungicides On Anurans Across Life Stages, Jenise Brown

Graduate Theses and Dissertations

Amphibians are declining at alarming rates globally. Multiple factors contribute to these declines, including chemical contaminants and emergent diseases. In recent years, agrochemical use, especially fungicide applications, has increased considerably. Previous studies have demonstrated that these agrochemicals leave application sites and enter wetlands via runoff and have detrimental effects on non-target organisms. For example, exposure to contaminants can have multifarious effects on amphibians, such as reducing their ability to deal with a secondary stressor, such as disease.

A pathogen that is found concomitant with chemical contaminants in aquatic systems is Batrachochytrium dendrobatidis (Bd). Bd has decimated amphibian populations worldwide. Susceptibility ...


Assessment Of A Modified Double Agar Layer Method To Detect Bacteriophage For Assessing The Potential Of Wastewater Reuse In Rural Bolivia, Sakira N. Hadley Jan 2013

Assessment Of A Modified Double Agar Layer Method To Detect Bacteriophage For Assessing The Potential Of Wastewater Reuse In Rural Bolivia, Sakira N. Hadley

Graduate Theses and Dissertations

Water scarcity is a global concern that impacts many developing countries, forcing people to depend on unclean water sources for domestic, agricultural, and industrial needs. Wastewater is an alternative water source that contains nutrients needed for crop growth. Wastewater reuse for agriculture can cause public health problems because of human exposure to pathogens. Pathogen monitoring is essential to evaluate the compliance of wastewater with established World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA) wastewater reuse guidelines. Indicator organisms are commonly used to detect pathogens in water and wastewater because they are quick and easy to measure, non-pathogenic ...


Reaction Enthalpy And Volume Profiles For Excited State Reactions Involving Electron Transfer And Proton-Coupled Electron Transfer, William Antonio Maza Jan 2013

Reaction Enthalpy And Volume Profiles For Excited State Reactions Involving Electron Transfer And Proton-Coupled Electron Transfer, William Antonio Maza

Graduate Theses and Dissertations

Electron transfer, ET, and proton-coupled electron transfer, PCET, reactions are central to biological reactions involving catalysis, energy conversion and energy storage. The movement of electrons and protons in either a sequential or concerted manner are coupled in a series of elementary reaction steps in respiration and photosynthesis to harvest and convert energy consumed in foodstuffs or by absorption of light into high energy chemi-cal bonds in the form of ATP. These electron transfer processes may be modulated by conformational dynamics within the protein matrix or at the protein-protein interface, the energetics of which are still not well understood. Photoacoustic calorimetry ...


Gradients In Season, Latitude, And Sea Ice: Their Effect On Metabolism And Stable Isotopic Composition Of Antarctic Micronekton, Erica H. Ombres Jan 2013

Gradients In Season, Latitude, And Sea Ice: Their Effect On Metabolism And Stable Isotopic Composition Of Antarctic Micronekton, Erica H. Ombres

Graduate Theses and Dissertations

Respiration, metabolic enzyme assays, and body composition parameters were measured in the Antarctic krill Euphausia superba during the summer, fall and winter on the Western Antarctic Peninsula (WAP). E. superba of all sizes decrease their metabolism from the summer to the winter. These same parameters were also measured along the WAP during the austral fall 2010. E. superba's enzyme activity indicated that there was a latitudinal gradient to the decline in metabolism along the WAP with the more northerly sites having significantly higher metabolic enzyme activities than the sites to the south.

Carbon (δ13C) and nitrogen (δ ...


Relative Survival Of Gags Mycteroperca Microlepis Released Within A Recreational Hook-And-Line Fishery: Application Of The Cox Regression Model To Control For Heterogeneity In A Large-Scale Mark-Recapture Study, Beverly J. Sauls Jan 2013

Relative Survival Of Gags Mycteroperca Microlepis Released Within A Recreational Hook-And-Line Fishery: Application Of The Cox Regression Model To Control For Heterogeneity In A Large-Scale Mark-Recapture Study, Beverly J. Sauls

Graduate Theses and Dissertations

The objectives of this study were to measure injuries and impairments directly observed from gags Mycteroperca microlepis caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were ...


Chlorophyll Fluorescence And Thermal Stress In Archaias Angulatus (Class Foraminifera), Heidi M. Toomey Jan 2013

Chlorophyll Fluorescence And Thermal Stress In Archaias Angulatus (Class Foraminifera), Heidi M. Toomey

Graduate Theses and Dissertations

ABSTRACT

Benthic foraminifers that host algal symbionts are similar to corals in that they rely on their algal endosymbionts for their energy needs, calcify prolifically, and are sensitive to changes in environmental conditions. They are abundant in the benthos of coastal coral-reef areas and are found throughout the tropical and subtropical regions. Pulse Amplitude Modulated (PAM) chlorophyll fluorometry and chlorophyll a extraction techniques were used to quantify and compare the photosynthetic responses of the benthic foraminiferal, Archaias angulatus and their isolated endosymbionts, Chlamydomonas hedleyi, to short-term changes in temperature. Maximum quantum efficiency (Fv/Fm) and rapid light curves ...


The Influence Of Propagation Method And Stand Age On Miscanthus X Giganteus Performance In Iowa, Usa, Nicholas Boersma Jan 2013

The Influence Of Propagation Method And Stand Age On Miscanthus X Giganteus Performance In Iowa, Usa, Nicholas Boersma

Graduate Theses and Dissertations

Climate change and a desire for oil independency have stimulated interest in dedicated biomass crops for domestic biofuels production. Miscanthus × giganteus Greef et Deu., an exceptionally productive crop in the Midwestern USA, exhibits many ideal biomass crop traits, notably sterility which decreases invasive potential. Although a labor intensive process, rhizome propagation is the most common method for vegetatively propagating M. × giganteus. Stem propagation, investigated here, alleviates many challenges associated with rhizome production. Utilizing 30 °C soil and the first five nodal stem segments increased M. × giganteus propagation rates 12 fold of reported rhizome multiplication rates. Stem propagated plants (SPs) were ...


Raman Spectroscopic Characterization And Analysis Of Agricultural And Biological Systems, Qi Wang Jan 2013

Raman Spectroscopic Characterization And Analysis Of Agricultural And Biological Systems, Qi Wang

Graduate Theses and Dissertations

Technical progresses in the past two decades in instrumental design, laser and electronic technology, and computer-based data analysis have made Raman spectroscopy, a noninvasive, nondestructive optical molecular spectroscopic imaging technique, an attractive choice for analytical tasks. Raman spectroscopy provides chemical structural information at molecular level with minimal sample preparation in a quick, easy-to-operate and reproducible fashion. In recent years it has been applied more and more to the analysis and characterization of agricultural products and biological samples. This dissertation documents the innovative research in Raman spectroscopic characterization and analysis in both biomedical and agricultural systems that I have been working ...


Effect Of Corn Stover Harvest And Winter Rye Cover Crop On Corn Nitrogen Fertilization, Jose L. Pantoja Jan 2013

Effect Of Corn Stover Harvest And Winter Rye Cover Crop On Corn Nitrogen Fertilization, Jose L. Pantoja

Graduate Theses and Dissertations

Improvement in N management to optimize corn N fertilization requirement and minimize NO33--N loss from agricultural fields is an ongoing need for continuous corn (Zea mays L.) and corn-soybean [Glycine max (L.) Merr.] production systems. This is especially important in Iowa as this state has the largest corn production across the U.S.A. The present dissertation includes two projects that evaluated corn response to N application and optimal fertilization rate. The first project evaluated the effect of corn stover harvest (SH) in continuous corn and the interaction with chisel plow and no-tillage systems; and the second project ...


Development And Optimization Of Algal Cultivation Systems, Martin Gross Jan 2013

Development And Optimization Of Algal Cultivation Systems, Martin Gross

Graduate Theses and Dissertations

This thesis describes research done on two novel algae cultivation systems. The first system was an attached algal growth system to facilitate biomass harvest with improved biomass yield. In the attached system, algal cells were grown on the surface of a material rotating between the nutrient-rich liquid phase and the carbon dioxide-rich gaseous phase. The algal cells from the attached growth system were harvested by simply scraping off the algal biofilm. The operation conditions of the attached growth system were optimized to improve biomass productivity. A harvesting frequency of 7 days with a rotational speed of 4 rpm resulted in ...


Building And Simulating Protein Machines, Ataur Rahim Katebi Jan 2013

Building And Simulating Protein Machines, Ataur Rahim Katebi

Graduate Theses and Dissertations

Glycolysis is a central metabolic pathway, present in almost all organisms, that produces energy. The pathway has been extensively investigated by biochemists. There is a significant body of structural and biochemical information about this pathway. The complete pathway is a ten step process. At each step, a specific chemical reaction is catalyzed by a specific enzyme. Fructose bisphosphate aldolase (FBA) and triosephosphate isomerase (TIM) catalyze the fourth and the fifth steps on the pathway.

This thesis investigates the possible substrate transfer mechanism between FBA and TIM. FBA cleaves its substrate, the six-carbon fructose-1,6-bisphosphate (FBP), into two three-carbon products - glyceraldehydes ...


Impacts Of Conventional And Organic Agriculture On Soil-Borne Entomopathogenic Fungi, Eric Harold Clifton Jan 2013

Impacts Of Conventional And Organic Agriculture On Soil-Borne Entomopathogenic Fungi, Eric Harold Clifton

Graduate Theses and Dissertations

Entomopathogenic fungi (EPF) kill pests and can diminish outbreaks. Species of EPF such as Beauveria bassiana and Metarhizium brunneum (formerly M. anisopliae) are significant mortality factors for several insects. Better understanding of these organisms is an essential step in developing strategies to conserve EPF in agricultural systems. We hypothesize that 1) organically farmed soil is more suitable to EPF than conventional soil, and 2) conventionally-farmed soil, coupled with the use of synthetic chemical inputs, could have negative impacts on EPF. In 2011 and 2012, soil was collected from organic and conventional fields of corn and soybean and the field margins ...


Fatty Acid And Polyketide Synthesis Enzymes: Sequences, Structures, And Mechanisms, David Cantu Jan 2013

Fatty Acid And Polyketide Synthesis Enzymes: Sequences, Structures, And Mechanisms, David Cantu

Graduate Theses and Dissertations

The fatty acid and polyketide synthesis enzymes were studied, and findings compose this dissertation. The thioester-active enzyme database (ThYme) was constructed, which provides almost all known sequences of fatty acid and polyketide synthesis enzymes classified and organized into families based on amino acid sequence similarity. ThYme aids in predicting active sites, catalytic residues, and mechanisms of individual sequences, as well as providing a standardized nomenclature. Detailed and timely reviews on thioesterases, ketoacyl reductases, hydroxyacyl dehydratases, enoyl reductases, and acyl carrier proteins, as well as their products and pathways, were also done.

Normal vibrational mode analysis showed that the dynamic behavior ...


Workflow Tools For Biological Applications, Marie C. Vendettuoli Jan 2013

Workflow Tools For Biological Applications, Marie C. Vendettuoli

Graduate Theses and Dissertations

When identifying best practices for multistep processes involving data analysis, it is fre- quently the case that the data scientist is asked to wear many hats simultaneouly: developer, programmer, statistician, graphic designer, writer, administrator. Although many scientists address these roles with great success, it is often at the expense of reproducibility, scalability, and organizational knowledge. The process of formalizing each step of the process creates op- portunity to apply lessons learned and proven tools from multiple disciplines to optimize each step of the transformation from raw data to usable output. This modular approach allows organizations to mix off the shelf ...


Biophysical Interactions In Prairie Pothole Wetlands Of Iowa: Consequences For Macroinvertebrate Assemblages And Ecosystem Condition, Kristine Maurer Jan 2013

Biophysical Interactions In Prairie Pothole Wetlands Of Iowa: Consequences For Macroinvertebrate Assemblages And Ecosystem Condition, Kristine Maurer

Graduate Theses and Dissertations

Wetlands are capable of supporting diverse assemblages of plants and animals, and performing various ecosystem services (e.g., waterfowl production, flood mitigation). However, the capacity of a wetland to perform these functions is dependent upon its condition (i.e., ecosystem condition, integrity, or health). Wetland condition is affected and reflected by internal (within-system) biophysical features, and interactions among these features. To protect and effectively manage wetlands, it is essential that we identify reliable determinants and indicators of wetland condition. As a result of the inherent complexity of wetland ecosystem interactions, this knowledge is difficult to obtain. The objectives of this ...


Reproductive Decisions Of Mountain Plovers In Southern Phillips County, Montana, Paul Daniel Blom Skrade Jan 2013

Reproductive Decisions Of Mountain Plovers In Southern Phillips County, Montana, Paul Daniel Blom Skrade

Graduate Theses and Dissertations

The Mountain Plover (Charadrius montanus) is a shorebird of conservation concern that breeds in the Great Plains and the Great Basin. They have an uncommon uniparental care system where males and females tend separate nests. Although males and females have similar incubation and chick-rearing responsibilities, it is thought that the males arrive first to the breeding grounds in early to mid-April, establish loose territories, and compete for females. Long-term monitoring of this species in north-central Montana has allowed for studies comparing the effectiveness of the two sexes at separately raising young, showing evidence for differences in nest and brood survival ...


Soil Carbon Cycling And Storage Of Bioenergy Cropping Systems Across A Heterogeneous Agroecosystem, Todd Allan Ontl Jan 2013

Soil Carbon Cycling And Storage Of Bioenergy Cropping Systems Across A Heterogeneous Agroecosystem, Todd Allan Ontl

Graduate Theses and Dissertations

Emerging markets for cellulosic bioenergy feedstocks provide opportunities for implementing soil conservation practices that restore soil carbon (C) stocks within agricultural landscapes. Conservation strategies--including conversion to no-till, using cover crops, and establishing perennial vegetation--alter belowground C cycling processes and increase soil C storage through protection of soil organic matter (SOM). In particular, marginal sites less suited for conventionally tilled annual row crops are being targeted as appropriate locations for conversion to perennial bioenergy crops. However, the effects of topography and variations in soil properties on belowground C cycling processes remain largely unknown. The goal of this research is to quantify ...


Hybrid Striped Bass: Culture And Use In Midwestern Waters, James Wamboldt Jan 2013

Hybrid Striped Bass: Culture And Use In Midwestern Waters, James Wamboldt

Graduate Theses and Dissertations

In response to increased demand from fisheries managers, the Iowa Department of Natural Resources and Iowa State University worked to produce standard operating procedures for pond culture of hybrid striped bass Morone saxatilis × M. chrysops in Iowa. In 2011 we evaluated an organic fertilization regime in nutrient rich earthen ponds. In addition to pond fertilization, the role of offering a supplemental commercial feed during phase I culture was also investigated within plastic-lined ponds. With greater utilization and stocking of hybrid striped bass fingerlings in local waters, we also sought to evaluate the effects that introductions have on the trophic dynamics ...


Development Of Best-Practices For Conserving Beneficial Insects Within Iowa's Agricultural Landscape, Kelly Ann Gill Jan 2013

Development Of Best-Practices For Conserving Beneficial Insects Within Iowa's Agricultural Landscape, Kelly Ann Gill

Graduate Theses and Dissertations

The annual value of crop pollination and biological control of plant pests provided by beneficial insects is estimated to be worth at least $22 billion to United States crop production. Beneficial insects that supply these services to agricultural lands are threatened by limited or suboptimal resources due to the loss of biodiversity in agroecosystems, which is a growing concern in agricultural states like Iowa. Conservation practices are recommended to address a multitude of conservation concerns related to Iowa's declining natural resources; however, guidelines for best practices that conserve beneficial insects are not well defined. Due to the valuable relationship ...


Corn Yield Variability On The Des Moines Lobe Of Iowa: Assessment Of Extent And Soil-Related Causes, Matthew Thomas Streeter Jan 2013

Corn Yield Variability On The Des Moines Lobe Of Iowa: Assessment Of Extent And Soil-Related Causes, Matthew Thomas Streeter

Graduate Theses and Dissertations

Precision agriculture techniques are an essential component to modern row crop agriculture in Iowa and can be used to create crop yield variability maps via geographic information systems. The first objective of this thesis was to explore the methodology that could be used to locate significant long-term corn yield variability on the Iowa Des Moines Lobe. A 158-ha site, consisting mainly of Clarion, Nicollet and Webster soil map units and containing multiple years of geo-referenced corn (Zea mays) yield data was selected. A cluster analysis tool was performed to locate spatially consistent corn yield variability (high, low and mean yield ...


Effects Of Perennial And Cover Crops On Hydrology In Iowa, Ryan Goeken Jan 2013

Effects Of Perennial And Cover Crops On Hydrology In Iowa, Ryan Goeken

Graduate Theses and Dissertations

Since European settlement, and beginning in the 1940's, two dramatic shifts in land use have occurred in Iowa - the first from prairie and forest to tile-drained farmland, and the second from diverse rotations to a heavier concentration of corn-soybean rotations and continuous corn. These shifts in land use and management have altered hydrological and biogeochemical cycles in the Upper Midwest, but perennial and cover crops have the potential to assist in mediating changes in these cycles.

The first study in this thesis examines how the perennial forage (PF) crop orchardgrass (Dactylis glomerata) affects subsurface drainage as compared to a ...