Agriculture Commons^™

Quantifying Crop Phenology For Food Sustainability Under Climate Change: Integration Of Remote Sensing, Machine Learning, And Ecosystem Modeling, Yanjun Yang

Theses and Dissertations--Plant and Soil Sciences

Climate change is projected to continue and accelerate significantly in the future if global greenhouse gas emissions are not curbed. Previous studies have shown that crop growth and production in agroecosystems are primarily determined by the weather conditions over the growing season. Crop phenology represents one of the most critical indicators in determining crop yield and adjusting the adaptation of crops to climate change. It provides essential information for monitoring and modeling crop growth dynamics and productivity. Therefore, understanding and quantifying the impacts of climate change on crop phenology and then agricultural production is crucial to formulate feasible climatic adaptation …

An Evaluation Of Eragrostis Tef For Future Cultivar Development, Eric Wayne Luteyn

Theses and Dissertations--Plant and Soil Sciences

The many benefits of utilizing teff (Eragrostis tef) as small grain is well documented in journal publications. Over time the domestication of this species has become essential to the diets of the local population and the livestock living in the African highlands. Current research points to a high diversity of trait characteristics found in many teff populations and the potential utilization of these traits to increase desirable characteristics in both grain and forage varieties. With the overarching goal of adding to what is already known about teff, this study evaluates the different traits that are of interest to …

Understanding The Cellular And Physiological Mechanisms Of Fertilization And Early-Stage Seed Development, Mohammad Foteh Ali

Theses and Dissertations--Plant and Soil Sciences

Flowering plants have evolved a unique double-fertilization process. Two sperm cells fuse with two female gametophytic cells, the egg and central cells within the ovule, giving rise to the embryo and endosperm, respectively. Sperm cells in flowering plants are nonmotile and delivered in close proximity to the egg and central cells by the pollen tube. Flowering plants have established filamentous actin (F-actin) based sperm nuclear migration system for successful fertilization. Prior to fertilization, the female gamete forms a mesh-like structure of F-actin that shows constant inward movement from the plasma membrane periphery to the center of the cell where the …

Building Capacity For Cool Season Vegetable Production In Kentucky: Strengthening Supply Chains Through Crop Model Development And Analysis Of A Farm-To-Institution Market, Chelsea Jo Maupin

Theses and Dissertations--Plant and Soil Sciences

Cool season vegetable crops are suitable for both direct-to-consumer (DTC) and farm-to-institution (FTI) markets in central Kentucky. However, crop planning for predictable harvest is challenging. Seasonality issues can be detrimental to FTI markets wherein institutions require consistent, large volumes of product. This research investigates both production and market aspects of salad crops in central Kentucky, through development of growing degree day (GDD) crop models for loose-leaf lettuce (Latuca sativa), carrots (Daucus carota subsp. sativus), and spinach (Spinacia oleracea), and through a case study analysis for a FTI initiative called the Salad Bar Program. Simple …

Invasion Of Plant Communities, Stephen L. Young, Sarah Kimball, Stephen J. Novak

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Due to numerous human activities, organisms have been transported and either accidentally or deliberately introduced all around the globe. Biological invasions are now considered to be one of the main drivers of global change because many invasive plants have severe ecological, economic, and health consequences. Thus, there is an ever-growing need to better understand invasions to determine how specific plant species are able to establish in communities and, in many cases, expand their range. Here, we describe the invasion process and how it contributes to the invasion of plant communities. We present an invasion-factor framework (IFF) model that uses three …

Predicting Spatial-Temporal Patterns Of Diet Quality And Large Herbivore Performance Using Satellite Time Series, Sean P. Kearney, Lauren M. Porensky, David J. Augustine, Justin D. Derner, Feng Gao

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Adaptive management of large herbivores requires an understanding of how spatial-temporal fluctuations in forage biomass and quality influence animal performance. Advances in remote sensing have yielded information about the spatial-temporal dynamics of forage biomass, which in turn have informed rangeland management decisions such as stocking rate and paddock selection for free-ranging cattle. However, less is known about the spatial-temporal patterns of diet quality and their influence on large herbivore performance. This is due to infrequent concurrent ground observations of forage conditions with performance (e.g., mass gain), and previously limited satellite data at fine spatial and temporal scales. We combined multi-temporal …

Predicting Biochemical Acclimation Of Leaf Photosynthesis In Soybean Under In-Field Canopy Warming Using Hyperspectral Reflectance, Etsushi Kumagai, Charles H. Burroughs, Taylor L. Pederson, Christopher M. Montes, Bin Peng, Hyungsuk Kimm, Kaiyu Guan, Elizabeth A. Ainsworth, Carl J. Bernacchi

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Traditional gas exchange measurements are cumbersome, which makes it difficult to capture variation in biochemical parameters, namely the maximum rate of carboxylation measured at a reference temperature (Vcmax25) and the maximum electron transport at a reference temperature (Jmax25), in response to growth temperature over time from days to weeks. Hyperspectral reflectance provides reliable measures of Vcmax25 and Jmax25; however, the capability of this method to capture biochemical acclimations of the two parameters to high growth temperature over time has not been demonstrated. In this study, Vcmax25 and Jmax25 were measured over multiple growth stages during two growing seasons for field-grown …

Far-Red Photography For Measuring Plant Growth: A Novel Approach, Cole Webb, F. Mitchell Westmoreland, Bruce Bugbee, Xiaojun Qi

Techniques and Instruments

A critical part of agricultural studies is determining plant stress and growth rate. Modern computer vision provides a series of tools that can be applied to derive this data. In this paper, we will show our findings, analyze their accuracy, and define a system capable of deriving this data with near-human accuracy in a fraction of the time. Denoising techniques applicable to this system will be discussed, as will our discoveries and findings. Finally, suggestions for further research opportunities will be provided.

Rural Feminism And Perspectives Of Women Farmers In The Agriculture Industry: "I Don't Think I'D Want To Be A Man In This Industry", Cassie M. Duncan

College of Graduate Studies: Theses & Dissertations

Women currently make up 36% of the workforce in the agriculture industry and are actively growing in number (National Agricultural Statistics Service, 2017). Historically, women’s roles in the agriculture industry were silent or ignored, which has had consequences for women, such as poorer quality of life (Meares, 1997). Today, women are becoming more and more involved in the agriculture industry, but still face inequality in the workplace due to their gender. This research aims to understand the day-to-day experiences and impact of gender for women who work in the production agriculture industry; and by doing so, expand Feminist Theory to …

Selected Dietary Plant-Based Proteins For Growth And Health Response Of Nile Tilapia Oreochromis Niloticus, Tzodoq O. Magbanua, Janice A. Ragaza

Biology Faculty Publications

Tilapia culture is one of the largest sectors of global aquaculture. Among the different species of tilapia, Nile tilapia (Oreochromis niloticus) is perhaps the top cultured species. The production of Nile tilapia has been continually increasing throughout the years resulting in genetic deterioration. Several tilapia strains with better growth performance and adaptive capability to survive in different culture conditions have been developed to alleviate the crisis. Increased demand for Nile tilapia implies higher farming cost. Plant-based proteins are utilized as partial or complete fishmeal replacements to reduce feed cost. However, these proteins can adversely affect and alter growth …

Early-Life Farm Exposures And Eczema Among Adults In The Agricultural Lung Health Study, Annah B. Wyss, Thanh T. Hoang, Hilde K. Vindenes, Julie D. White, Sinjini Sikdar, Marie Richards, Laura E. Beane-Freeman, Christine G. Parks, Mikyeong Lee, David M. Umbach, Stephanie J. London

Mathematics & Statistics Faculty Publications

Background

Several studies conducted in Europe have suggested a protective association between early-life farming exposure and childhood eczema or atopic dermatitis; however, few studies have examined associations in adults.

Objectives

We investigated associations between early-life exposures and eczema among 3217 adult farmers and farm spouses (mean age, 62.8 years) in a case–control study nested within an US agricultural cohort.

Methods

We used sampling-weighted logistic regression to estimate odds ratios and 95% confidence intervals for associations between early-life exposures and self-reported doctor-diagnosed eczema (273 cases) and polytomous logistic regression to estimate odds ratios (95% confidence intervals) for a 4-level outcome combining …

The Comparison Of Three Different Fecal Egg Counting Techniques And Their Ability To Perform A Fecal Egg Count Reduction Test, Diana J. Summitt

Graduate Theses/Dissertations

A comprehensive gastrointestinal parasite control program includes an understanding of common parasites, application of chemotherapeutic agents, as well as frequent and appropriate diagnostic testing. An effective control program is essential for facilities such as animal shelters, that deal with large populations of transient canines with unknown parasite exposure and deworming history. The identification of a sensitive flotation method to evaluate anthelmintic efficacy is critical in monitoring parasite populations for drug resistance. The objective of the current study was to compare three different fecal egg counting technologies and their ability to perform a fecal egg reduction test. The flotation techniques evaluated …

Minimum Dataset And Metadata Guidelines For Soil-Test Correlation And Calibration Research, Nathan A. Slaton, Sarah E. Lyons, Deanna L. Osmond, Sylvie M. Brouder, Steve W. Culman, Gerson L. Drescher, Luciano C. Gatiboni, John Hoben, Peter J.A. Kleinman, Joshua M. Mcgrath, Robert O. Miller, Austin Pearce, Amy L. Shober, John T. Spargo, Jeff J. Volenec

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Soil-test correlation and calibration data are essential to modern agriculture, and their continued relevance is underscored by the expansion of precision farming and the persistence of sustainable soil management priorities. In support of transparent, science-based fertilizer recommendations, we seek to establish a core set of required and recommended information for soil-test P and K correlation and calibration studies, a minimum dataset, building on previous research. The Fertilizer Recommendation Support Tool (FRST) project team and collaborators are developing a national database that will support a soil-test-based nutrient management decision aid tool. The FRST team includes over 80 scientists from 37 land-grant …

Curriculum Development Of Agricultural Educators In South Dakota, Mercedes Lemke

Electronic Theses and Dissertations

Curriculum development is an essential component of teaching. Understanding how agriculture education teachers utilize, develop, and adapt content to curriculum can benefit teachers to spend less time on curriculum development. Recognizing the way agriculture education teachers use content in curriculum implementation will allow curriculum developers to create materials that can effectively be used by teachers. This study also looked at the affects of how COVID19 pandemic affected the way teachers locate and develop curriculum. The purpose of this study was to evaluate the way agriculture education instructor’s usage of content for curriculum development, implementation decisions and the affects of the …

Effect Of Essential Oils In The Control Of Fungal Diseases In Small Grains, Esneider Mahecha Bojaca

Electronic Theses and Dissertations

Spring wheat (Triticum aestivum L.) and oats (Avena sativa L.) are important crops due to their high consumption in our daily diet worldwide. They are the main food of consumption per capita due to the high amino-acid content as well of vitamins. However, grain production is limited due to the negative impact of the diseases that cause significant yield loss. Diseases in oats, such as crown rust caused by Puccinia coronata f. sp. avenae (Pca), and in wheat such as Fusarium head blight (FHB) caused by the fungus Fusarium graminearum. Foliar diseases such as tan spot incited by the fungi …

Characterizing Implied Volatility Functions From Agricultural Options Markets, Andrew M. Mckenzie, Michael R. Thomsen, Michael K. Adjemian

Agricultural Economics and Agribusiness Faculty Publications and Presentations

We provide the first comprehensive characterization and comparison of implied volatility functions for five major agricultural options markets—corn, soybeans, soft red winter wheat, live cattle, and feeder cattle—using intraday tick data. Our results show that cattle markets exhibit a distinct leftward skew, which is puzzling and indicates that out-of-the-money traded put options are theoretically overpriced. In contrast, we find that grain market implied volatility functions display a flatter, less pronounced smile pattern. We examine market sentiment induced short-term hedging pressures using Commodity Futures Trading Commission reports, and market uncertainty around Cattle on Feed reports, as potential causes of the cattle …

Observing Gravitropism In Brassica Rapa Roots, Trang Ly, Maya O'Callagham, Lan Poeschl, Adil Saeed, George Zorn

Undergraduate Research Posters

The objective of this experiment is to observe the effect of gravitropism on the orientation of Brassica rapa (B. rapa) roots. Specifically, amyloplasts that reside at the bottom of root tips act as gravity sensors. As plants are disturbed from upright orientation, roots automatically grow according to the downward pull of gravity. It is hypothesized that as the angle of rotation increases, the angle of root growth is inversely proportional. Five plants containing four seeds of B. rapa were grown over the course of 10 days. Each plates, aside from the control, were rotated once 90°, 80°, and 270° to …

Application Of Mass Spectrometry For Characterization Of Plant-Based Phenolics And Alkaloids, Masoumeh Dorrani

Theses and Dissertations--Chemistry

Plant-derived compounds have the potential to produce value-added compounds with a variety of applications. For example, the lignin part of the lignocellulosic biomass, produced in large quantities as waste from the paper and pulp industries, is a rich source of phenolics with potential applications in the renewable energy sector, pharmaceutical, and chemical industries. On the other hand, plant alkaloids are the primary source for developing plant-derived therapeutics. Unfortunately, the recalcitrant nature of plant cell walls, low extraction yields of small secondary metabolites, and the lack of effective analytical methods for a rapid and accurate identification of plant-based compounds and plant’s …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports (ETD)

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Phomopsis Stem Canker Of Sunflower (Helianthus Annuus L.): Etiology And Epidemiological Conditions Affecting Endophytic Population Of Diaporthe Spp., And Fungicide Efficacy, Nabin Kumar Dangal

Electronic Theses and Dissertations

Phomopsis stem canker (PSC), caused by species of Diaporthe, is a major disease of sunflower (Helianthus annuus L.) in the U.S., which can cause yield loss over 40%. The disease prevalence increased since 2010 in the major sunflower producing U.S. states of Nebraska, Minnesota, North Dakota, and South Dakota. Previous studies on the use of foliar fungicides in managing Phomopsis stem canker indicated mixed results on their efficacy in disease reduction and yield gain. Additionally, we do not have sufficient information on asymptomatic colonization by endophytic Diaporthe on sunflower tissue and how foliar fungicide and weather parameters affect the prevalence …

Study Of Root System Architectural Traits Of Oat And Response To Endophyte Inoculation And Drought Stress, Krishna Ghimire

Electronic Theses and Dissertations

Oat is an important cereal crop grown worldwide. Oats have the potential to contribute to human health due to their unique nutritional attributes. Developing oat cultivars with efficient root systems able to extract heterogeneously distributed soil resources can help maintain yield under drought conditions and in nutrient poor soil. Various root traits determine the soil volume that is explored by the root system for resource acquisition. Knowledge about the genetic control of oat root traits and response to biotic and abiotic environmental factors is lacking. Identifying quantitative trait loci associated with root traits and understanding the response of roots to …

Reduced Chelate Strength Increases Iron Bioavailability For Monocots In Hydroponic Culture, Paul Kusuma, Bruce Bugbee

Hydroponics/Soilless Media

Hydroponically grown corn (Zea mays) is highly susceptible to Fe-chlorosis. Iron (Fe) is essential for chlorophyll synthesis. Metals bound to chelates have reduced bioavailability (activity) compared to free ions.

Policy Sustainability Issues: Case Study Of Cassava Farmers In Ikorodu. Lagos, Nigeria, Medinat Oluwatoyin Adetunji

Walden Dissertations and Doctoral Studies

The inconsistency and lack of continuity of Nigeria's agricultural policies impact the cassava sector. Despite being the world's biggest producer, the country is yet to benefit from the advantage due to a lack of sustainable growth. The situation manifests in terms of low productivity, low production level, and poor income to the farmers. The purpose of this qualitative study was to investigate the experiences and perceptions of the cassava farmers on cassava policies and the effect on their income and livelihoods in the Ikorodu local government of Lagos State. This qualitative study adopted a case study research design using participatory …