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Soybean Nitrogen Dynamics: Nitrogen Fixation, Yield, And Residue Decomposition, S Carolina Cordova Martinez Jan 2018

Soybean Nitrogen Dynamics: Nitrogen Fixation, Yield, And Residue Decomposition, S Carolina Cordova Martinez

Graduate Theses and Dissertations

Nitrogen (N) a crucial element for plant growth, often limits net primary productivity of agroecosystems. In agricultural systems it is vital to have proper management of N to secure productivity and environmental sustainability. Soybean [Glycine max (L.) Merr.] is the second most important crop in the US Corn Belt, and it can fix part of its N through biological N fixation. The overarching goal of this research was to investigate soybean N fixation dynamics in response to environmental factors, and plant tissue decomposition to understand better N cycling and improve Midwestern US N budget estimations.

A long-term incubation study was ...


Using Genomic And Gene Expression Methods To Understand The Phenotypic Response Of Soybean To Sudden Death Syndrome Caused By Fusarium Virguliforme, Alexander Stephen Luckew Jan 2018

Using Genomic And Gene Expression Methods To Understand The Phenotypic Response Of Soybean To Sudden Death Syndrome Caused By Fusarium Virguliforme, Alexander Stephen Luckew

Graduate Theses and Dissertations

Soybean sudden death syndrome (SDS) is one of the most important soybean diseases in the Midwestern United States, leading to average losses of $396 million per year from 1996 to 2015. The causal agent of SDS, soilborne fungus Fusarium virguliforme (Fv), causes root rot symptoms and releases phytotoxins taken up by the plant to produce chlorosis and necrosis in the leaves. The main management practice used to reduce the impact of SDS is planting resistant soybean cultivars. Resistance to SDS is known to be quantitative with 88 known quantitative trait loci (QTL) based on Soybase.org. Many of these QTL ...


Winter Cereal Rye And Selected Brassica Cover Crops For Forage Prior To Soybeans, Timothy James Sklenar Jan 2018

Winter Cereal Rye And Selected Brassica Cover Crops For Forage Prior To Soybeans, Timothy James Sklenar

Graduate Theses and Dissertations

Despite myriad benefits to incorporating winter cover crops into conventionally managed row crop systems farmer adoption remains low in Iowa. Commonly cited apprehensions include the costs associated with managing cover crops without any short term economic benefits and the complexities associated with management of cover crops. The management of cover crops as a forage could potentially help address both of these issues while at the same time enhancing the environmental sustainability of conventionally managed systems. The work provided in this thesis is an attempt to evaluate the potential for four selected species to be managed as dual-purpose winter cover crops ...


Functional Characterization Of A Fungal Polyamine Oxidase Fvpo1, Jordan Lillian Baumbach Jan 2018

Functional Characterization Of A Fungal Polyamine Oxidase Fvpo1, Jordan Lillian Baumbach

Graduate Theses and Dissertations

Soybean is an important source of protein and oil for both human and animal nutrition. The United States is the world’s leading soybean producing nation. In 2016, the U.S. soybean production was valued over 40.9 billion dollars. Sudden death syndrome (SDS) of soybean is ranked as one of the top ten yield limiting disease of soybean and is caused by the pathogen Fusarium virguliforme. Fusarium virguliforme is a soil borne fungal pathogen, which infects soybean roots resulting in both root sot symptoms and foliar chlorosis and necrosis. To date there is no known single gene resistance to ...


Effect Of Soybean Sudden Death Syndrome On Seed Quality And Agronomic Trait Qtls, Josh Knight Jan 2018

Effect Of Soybean Sudden Death Syndrome On Seed Quality And Agronomic Trait Qtls, Josh Knight

Graduate Theses and Dissertations

Soybean production has grown over the years and soybean has become one of the main crops in the world. Protecting and advancing soybean production has become a main goal for soybean producers and breeders. The following chapters look at the soybean-pest interaction for one of the leading soybean diseases called Fusarium virguliforme. that causes sudden death syndrome (SDS) in soybean, and potential genetic regions controlling seed quality traits. Chapter two compares Fusarium virguliforme, Fv inoculated fields vs non-inoculated fields for soybean agronomic and seed quality traits. SDS is one of the leading soybean pests in the United States. This study ...


Evaluation Of Soybean Grain Yield As Influenced By Soybean Seeding Rate And Fomesafen Herbicide, Paul Parcher Jan 2018

Evaluation Of Soybean Grain Yield As Influenced By Soybean Seeding Rate And Fomesafen Herbicide, Paul Parcher

Creative Components

Glyphosate (N-(phosphonomethyl)glycine) herbicide has been extensively used on several herbicide tolerant crops in the United States since the introduction of the first commercially available genetically modified glyphosate-tolerant soybean [Glycine max (L.) Merr.] seed in 1996. The launch of commercially available glyphosate-tolerant corn (Zea mays L.) seed in 1998 provided farmers in Iowa and other states, where corn and soybean are primarily grown, the ability to apply glyphosate to every acre of these crops annually.


Effects Of A Plant Growth Regulator Product On Soybean At R2-R3, Geoffrey Klumpp Jan 2018

Effects Of A Plant Growth Regulator Product On Soybean At R2-R3, Geoffrey Klumpp

Creative Components

The agricultural industry had a rapid increase in commodity prices from late in 2010 until the fall of 2014. With those higher prices, there was a niche market for added-value products brought to the market, many of which promised the local grower a five-bushel yield increase per acre on soybeans. I wanted to focus on a select group of these products, plant growth regulators (PGRs). I specifically worked with a commercial product that contained three phytohormones, cytokinin, a gibberellic acid, and an auxin. For this project, there were thirteen side-by-side trials for each of the following years, 2015, 2016, 2017 ...


Evolution Of Soybean Weed Management In The United States, Aaron Rowe Jan 2018

Evolution Of Soybean Weed Management In The United States, Aaron Rowe

Creative Components

Weeds have been an unwanted nuisance since the beginning of agriculture. The processes and technologies utilized to manage this yield limiting problem have evolved over time. Soybean [Glycine max (L.) Merr.] production in the United States has experienced all of the major agriculture revolutions. This has included horse-drawn field implements, tractor power implementation, chemical era, and the most recent era of biotechnology. There has been a continuous gain in efficiencies with the discovery and introduction of new technologies to manage weeds in soybeans. A period of rapid discovery and introduction of new and novel herbicide sites of action (SOA) with ...