Plant Sciences Commons^™

Assessing Functional Biodiversity For The Future Of Plants, Planet, And People, Ali Loker

Doctor of Plant Health Program: Dissertations and Student Research

Biodiversity plays a critical role in supporting life in global ecosystems and its links to ecosystem services and sustainability are recognized by scientific and non-scientific communities. Growing awareness of the importance of biodiversity is accelerated by discussions of its loss, and how to design interventions to conserve and mitigate a biodiversity crisis. Stakeholders are funding and implementing assessment strategies at various scales to help direct conservation efforts. There is also growing interest in measuring and communicating biodiversity outcomes.

Functional biodiversity characterizes the multiplicity of life forms into groups based on their diverse contributions to natural and agro-ecosystems. Assessing functional biodiversity …

Food Security & Urban Agriculture - Considerations For Soil Improvements And Crop Planning, Aaron Sedivy

Doctor of Plant Health Program: Dissertations and Student Research

Urban agriculture provides many benefits, such as energy conservation, rainwater remediation, increased aesthetic and property value, and therapeutic use for physical, cognitive, and emotional wellbeing. Urban agriculture can also provide critical integrity to each pillar of food security: availability, access, utilization, and stability. As urban agricultural activities increase, social interactions will follow in concert. This will provide opportunities for building trust through the two-way communication of contrasting perspectives, cultures, and beliefs using impartial narratives. Growers can use knowledge and understanding gained from these positive social interactions to formulate their personal paradigms for practice and better meet the needs of each …

Image Analysis And Machine Learning In Agricultural Research, Xinzheng Chen

Doctor of Plant Health Program: Dissertations and Student Research

Agricultural research has been a focus for academia and industry to improve human well-being. Given the challenges in water scarcity, global warming, and increased prices of fertilizer, and fossil fuel, improving the efficiency of agricultural research has become even more critical. Data collection by humans presents several challenges including: 1) the subjectiveness and reproducibility when doing the visual evaluation, 2) safety when dealing with high toxicity chemicals or severe weather events, 3) mistakes cannot be avoided, and 4) low efficiency and speed.

Image analysis and machine learning are more versatile and advantageous in evaluating different plant characteristics, and this could …

Bridging The Gap Between Research And Smallholder Farmers Through Community-Based Development Organizations, Nathan D. Fortner

Doctor of Plant Health Program: Dissertations and Student Research

Food demand is expected to increase 30% to 62% by 2050 according to recent estimates. Yet, annual increases in agricultural productivity have slowed and plateaued since the green revolution increases of the 1960’s. Two strategies to help address future food demand are reducing post-harvest loss and consumer waste, and closing the yield gap between potential and farmer realized yields. Some of the largest yield gaps are those of smallholder farmers. While solutions may exist to close these gaps, delivering and integrating solutions into smallholder production systems is a complex process involving research, extension, cultural factors, government policy, NGOs, private industry, …

Climate Resilient Potato Systems For The 21st Century And Beyond, Brett A. Lynn

Doctor of Plant Health Program: Dissertations and Student Research

Climate change’s effects will dramatically reshape food systems and food security in the twenty-first century and beyond. Given potato’s susceptibility to heat and drought, climate change is poised to disproportionately affect potato production. Globally, potato is the fourth most important crop and yields a higher caloric density than any other commercial crop. Thus, disruptions to potato production bear serious implications for global food security.

In the United States, considerable potato production occurs in the arid West, which already faces water scarcity. This scarcity is anticipated to increase in many areas due to climate change. In addition to scarcity, growers will …

It Takes Brains: Cultivating The Learning Process For Effective Science Communication, Amy D. Hauver

Doctor of Plant Health Program: Dissertations and Student Research

Learning is a complex, subjective process. An important perspective on learning is that anyone, regardless of their level of education, can participate in learning about science and contribute to their community. The public increasingly looks towards online resources to find answers to challenges, so it is necessary that people become empowered to take information about issues rooted in science and apply them to their own lives and communities. In my experiences as a learner and educator, understanding the learning process provides a framework to design successful learning environments.

Since the brain is the organ most closely associated with the process …

Site-Specific Pest Management In Nebraska Corn And Soybean Production Systems, Zachary D. Rystrom

Doctor of Plant Health Program: Dissertations and Student Research

Site-specific management (SSM) is widely used by farm producers to fertilize their fields. However, whole field management is currently practiced in integrated pest management (IPM). Site-specific management and agricultural technology can improve IPM especially when precision application of inputs can reduce selection pressure on pest populations, benefit the environment, or save costs of inputs. There is potential for site-specific pest management (SSPM) where pests, or environments vary spatially, and recommended management practices can be applied with precision. Three case studies are evaluated for SSPM to be applied in Nebraska corn and soybean production systems including corn rootworm, preemergence herbicides, and …

The Impact Of Beneficial Organisms In Corn Agroecosystems, Callie Rosalind Braley

Doctor of Plant Health Program: Dissertations and Student Research

Corn is one of the world’s, and Nebraska’s, most important crops. Millions of acres are planted to corn each year in the Cornhusker State. However, each year there are a plethora of arthropod, weed, and microorganism pests that rob farmers of reaching their maximum yield potential. There are many options available to manage these pests in corn agroecosystems, but one option is often underutilized: beneficial organisms. For each pest, there are a variety of natural enemies that can assist in mitigating the damage caused by pests.

Many beneficial organisms exist, and they can be grouped by the type of pest …

Intricacies In Agronomic Management: The Role Of Interdisciplinary Education, Adam M. Striegel

Doctor of Plant Health Program: Dissertations and Student Research

As a science, agronomy is built upon the connection of inter-disciplinary fields of study. Management (M) of various discipline considerations (and their subsequent interactions) can be influenced by and have significant effects on genetic by environment (GxE) expression. This has led to the promotion of GxExM systems. However, optimizing GxExM programs requires extensive, interdisciplinary knowledge. To evaluate interdisciplinary training provided in undergraduate education, 11 four-year universities were selected in the United States that offer baccalaureate degree majors in agronomy or crop science. Surveys of undergraduate programs of study were conducted, with all required coursework separated into general degree components (general …

The Importance Of Communication Skills To Independent Crop Consultants, Lindsay Overmyer

Doctor of Plant Health Program: Dissertations and Student Research

Independent crop consulting companies provide services to farmers by scouting (i.e., collecting field observations of plants and pests) and developing management recommendations for individual fields. In production agriculture, independent crop consultants (ICCs) are professionals who are independent of product sales. They are knowledgeable in many disciplines including plant pathology, entomology, weed science, plant science, economics, water management, and soil science. However, ICCs must also have extensive communication skills to communicate to their audience of field scout(s), farmers, industry professionals, and government officials. The goal of this document is to examine how ICCs use their communication skills and how they can …

Addressing The Challenges Facing Wheat Production: Nebraska And International Breeding Efforts, Sarah Blecha

Doctor of Plant Health Program: Dissertations and Student Research

Bread wheat, Triticum aestivum L., provides 20 percent of the global daily calorie intake. It is the third most important food crop, after rice and corn. Biotic challenges significantly reduce wheat yield; chemical control can be a solution but can be cost prohibitive for subsistence farmers. For many farmers, genetic resistance to biotic stresses can be the most cost effective solution.

The International Center for Agricultural Research in the Dry Areas (ICARDA) and the Nebraska Small Grains Breeding Program have been addressing these wheat production challenges. ICARDA is part of an international research consortium to increase wheat yield and tolerance …

Science Communication In Agriculture: The Role Of The Trusted Adviser, Lee Galen Briese

Doctor of Plant Health Program: Dissertations and Student Research

Agronomy is not simply the selling of agricultural products to farmers, nor is it the process of solving singular production problems. Agronomy is defined as the integrated, holistic perspective of agriculture (ASA, 2019) and “agronomists are specialists in crop and soil sciences, as well as ecology” (ASA, 2019). While scientific investigation and discovery are essential to understanding systems function, the tangible benefits from our knowledge stems from the application to solve problems. Clear communication is vital to successfully help stakeholders understand the importance of the science and help scientists understand the challenges stakeholders face. However, to successfully put science into …

Defining, Measuring, And Applying Soil Quality: An Unresolved Debate, Salvador Ramirez Ii

Doctor of Plant Health Program: Dissertations and Student Research

Paradigm shifts occur periodically in the sciences. Proposed paradigm shifts offer opportunities to reexamine extant paradigms and evaluate new ones. Soil science experienced a controversy resembling a proposed paradigm shift in the late 1990s and early 2000s when it grappled with the idea of soil quality (SQ). The most contentious points in the SQ debates were (1) the word “quality” itself and designing a functional definition, (2) identifying appropriate soil quality indicators, (3) the integration of soil quality indicators, and (4) the interpretation of soil quality indicators. The latter three disagreements were rooted in the established, fundamental, soil science paradigm. …

A Brief History Of Corn: Looking Back To Move Forward, Jon Derek Pruitt

Doctor of Plant Health Program: Dissertations and Student Research

Maize was domesticated from teosinte in Mexico some 7,000 to 10,000 years ago and quickly spread through the Americas. It has become one of the most important crops at a local and global level. Two types, Northern Flint corn and Southern Dent corns provided the basis of the genetic background of modern maize hybrids. The development of hybrids, first double-cross and later single-cross hybrids, along with a transition to high input farming provided huge yield increases, which have continued to improve with improving technology.

Increase in maize production also caused a rise in Western corn Rootworm (Diabrotica virgifera virgifera …

Managing Drought Stress In California Agricultural Systems, Gregory D. Brittain Jr.

Doctor of Plant Health Program: Dissertations and Student Research

California is currently facing a historic drought, and this has led many farmers in the state to severely cut back on irrigation. Optimal use of water for irrigation requires a comprehensive understanding of how plants respond physiologically to water stress (Chapter 1). By monitoring water requirements in crops and managing irrigation to meet those requirements, growers can significantly reduce water use (Chapter 2). This can be done through improving application efficiency of irrigation technology as well as increasing the water use efficiency of the crops themselves. Deficit irrigation practices can be used to manipulate the physiology of water use in …

A Vision For Extension: Case Studies On Managing Extreme Weather Challenges In Corn, Anthony J. Mcmechan

Doctor of Plant Health Program: Dissertations and Student Research

Global demand for corn is projected to rise in the coming decades to meet the food and fuel requirements of an increasing human population. Technological innovations have significantly improved corn yields over the past few decades; however, corn production is continually limited by unfavorable weather conditions. Extreme weather events put pressure on producers, adjustors, and consultants to make quick management decisions to maintain the highest return on their investment. Proper management decisions require an understanding of plant response and practical ways of applying this knowledge under real world conditions.

The following document was written after completing a six-month internship at …

Canola: A Modern Crop For A Modern Era, Kenneth J. Roché

Doctor of Plant Health Program: Dissertations and Student Research

The University of Nebraska-Lincoln Doctor of Plant Health program is a professional doctorate program with a comprehensive approach to plants and agriculture. The program emphasizes a broad interdisciplinary education across all plant-related disciplines, practical learning, research, and experience through internships. For my final required internship, I worked as a senior agricultural research intern with Research Designed for Agriculture (RD4AG) in Montana. RD4AG is a contract research organization based in Yuma, AZ with over thirty-years of experience. During my three month internship at RD4AG in Montana, a large portion of my responsibilities centered on managing regulated canola trials that were undertaken …

Producing Quality Barley For The Malting Industry, Haley H. Oser Dph

Doctor of Plant Health Program: Dissertations and Student Research

The University of Nebraska – Lincoln Doctor of Plant Health program requires each student to fulfill a professional internship over the last summer of the program. For my internship, I worked as a Barley Scientist Intern for MillerCoors and Golden Malting in Golden, Colorado. During this internship I gained a fundamental understanding of malting barley production with a significant emphasis on grain quality. Barley produced for malting must fulfill strict industry quality standards before it is accepted by the head maltsters. These quality standards include: a high germination rate, low moisture content, protein content within an acceptable range and the …

Managing Threats To The Urban Forest: From Dutch Elm Disease To Emerald Ash Borer - Learning From Experience, Christopher J. Borman

Doctor of Plant Health Program: Dissertations and Student Research

The urban forest provides important essential services to all municipalities; however, its value is often overlooked. The urban forest contributes to energy savings, environmental benefits, psychological well-being, and social benefits. Managing the urban forest in a sustainable manner is important if we wish to benefit from these services well into the future. Reliable management techniques have been created through previous experiences with pests, and these should be utilized and improved for use on urban forests.

American elm (Ulmus americana L.) was once a major component of the urban forests of North America. In 1927, Dutch elm disease (DED) was …

Agricultural Development In The Northern Savannah Of Ghana, Tara N. Wood

Doctor of Plant Health Program: Dissertations and Student Research

Since declaring independence in 1957, the Republic of Ghana has become a stable constitutional democracy. Ghana’s economy has grown substantially over the past decade, yet remains primarily agrarian, accounting for 50% of the total employment and 25% of the country’s Gross Domestic Product. Smallholder rain-fed farming using rudimentary technologies dominates the agricultural sector accounting for 80% of total agricultural production. Approximately 90% of smallholder farms are less than two hectares in size, and produce a diversity of crops. The major crops cultivated in Ghana include numerous cereal, root and tuber, leguminous, fruit, vegetable and industrial crops. Maize is the most …