Agriculture Commons^™

Incorporation Of Native Plants For Biodiversity Conservation In South Texas Agroecosystems, Kaitlynn M. Lavallee

Theses and Dissertations

I address the concerning disconnect between food production and regenerative ecological principles. First, understanding the foundational processes of seed-dormancy and germination are essential for successful restoration efforts using native species. We examine four common seed treatments (aerated hydroprime, acid scarification, cold stratification, sand scarification) on twelve commercially available species native to south Texas. Pappophorum bicolor Fourn. (pink pappusgrass) was sown in the field with the aerated hydroprime treatment, D. virgatus (Willd.) B.L. Turner (prostrate bundleflower) was planted after sand scarification treatment, and Ratibida columnifera (Nutt.) Woot. & Standl. (Mexican hat) was seeded without treatment. Small-scale field trials were conducted to …

Native Plant Allelopathy: A Potential Approach To Limit Invasive Grass Encroachment In Thorn Forest Restoration, Emily A. Mullins

Theses and Dissertations

Less than 5% of the Tamaulipan thorn forest remains in the United States. For this reason, there have been many attempts at restoration of this ecosystem. Oftentimes these attempts are unsuccessful due to the high prevalence of invasive African grasses that outcompete the seedlings. In an effort to improve the efficacy of these restoration efforts, native plant allelopathy has been examined for its ability to exclude invasive guineagrass. Native species were surveyed and selected species were tested for allelopathy in laboratory bioassays. The species that exhibited allelopathy in the laboratory were then evaluated in pot experiments for their ability to …

Improving Sustainable Fertilizer Practices For Pomegranate By Leaf Nutrient Concentration Evaluation And Fertilizer Trials, Minh Le

Master's Theses

Fruit tree leaf nutrient concentrations are commonly used to determine fertilizer rates, but information is limited regarding nutrient requirements, seasonal N uptake and removal rates, and soil N dynamics for pomegranate. Relationships between fertilizer rates, leaf nutrient concentrations, fruit yield and quality were examined in five mature, commercial California ‘Wonderful’ pomegranate orchards. Site 1 was observed for two growing seasons (2018-2019) and sites 2-5 were observed for one season (2018 or 2019). In 2018, 150, 300, or 450 g N/tree was applied at sites 1-3 in a single application at early fruit development or in two equal applications at early …

Eelgrass (Zostera Marina) Population Decline In Morro Bay, Ca: A Meta-Analysis Of Herbicide Application In San Luis Obispo County And Morro Bay Watershed, Tyler King Sinnott

Master's Theses

The endemic eelgrass (Zostera marina) community of Morro Bay Estuary, located on the central coast of California, has experienced an estimated decline of 95% in occupied area (reduction of 344 acres to 20 acres) from 2008 to 2017 for reasons that are not yet definitively clear. One possible driver of degradation that has yet to be investigated is the role of herbicides from agricultural fields in the watershed that feeds into the estuary. Thus, the primary research goal of this project was to better understand temporal and spatial trends of herbicide use within the context of San Luis …

Optimization Of In-Vessel Food Waste Composting: Enzyme Activity And Microbial Dynamics, Ayawovi Selom Ametepe

Graduate Theses and Dissertations

A series of greenhouse-based, rotary-drum bioreactor experiments was designed to study microbial dynamics and enzyme activity during optimization of food waste composting. This work aims to optimize food waste composting by defining the best food waste-to-bulking agent proportion controlling conditions and by evaluating the food waste composting process when inoculated by a bacterial inoculant product compared to uninoculated compost. Three experiments were run in total. The two first experiments were conducted for 48 days with sampling at each step of composting, while the third experiment last 50 days and included one extra sampling date. In the first experiment, 50:50, 65:35 …

Influence Of Burning And Grazing Management Practices On Subirrigated Sandhill Meadow Hay Production, Tara M. Harms

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Subirrigated meadows are a valuable forage resource to Sandhills ranching operations being used for hay production, grazing, or a combination of both. Practices that sustain meadow productivity should be encouraged to ensure a consistent feed supply for cattle. The potential influence of prescribed burning or pre-freeze and post-freeze grazing on forage production and quality are not well understood on these meadows. In grasslands, including meadows, excess dead plant material can accumulate, causing a potential reduction in forage yield and quality. Results of our three-year field study suggest that burning meadows in the spring is a suitable management option to remove …

Fungicide Resistance: Surveillance, Risk Assessment And Evolution In Two Soil-Borne Pathogens, Nikita Gambhir

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Fungicide-resistant pathogens are an increasing threat to fungicide efficacy and plant health. The goal of this dissertation was to advance the foundational knowledge required to prevent and detect fungicide resistance development in the seedling disease pathogen, Rhizoctonia zeae and the white-mold pathogen, Sclerotinia sclerotiorum. Corn and soybean fields in 12 states (Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Nebraska, South Dakota, and Wisconsin) were surveyed for R. zeae. In vitro fungicide sensitivity was determined for 91 isolates to fludioxonil, sedaxane, and/or prothioconazole. Rhizoctonia zeae was sensitive to all fungicides (EC₅₀ < 3 µg/ml) except azoxystrobin (EC₅₀ > 100 µg/ml). In …

Improving The Accuracy Of Genomic Predictions: Investigation Of Training Methods And Data Pooling, Johnna Lynn Baller

Department of Animal Science: Dissertations, Theses, and Student Research

One of the primary factors in the response to selection is the accuracy of selection. This study focused on methodologies to predict breeding values (BV) accurately within multi- and single-step genomic evaluations. Factors including cross-validation methods, dependent variables, and genotyping strategies were assessed on the accuracy of genomic BV while using multi-step prediction in real and simulated data. In both cases, random clustering led to largest estimated accuracies compared to clusters based on k-means, k-medoids, and principle component analysis, but differences in bias were not detected. Using deregressed estimated BV (EBV) to estimate SNP effects led to larger accuracies and …

Entry-Level Workplace Competencies Needed By Graduates Of A Community College Agriculture Program: A Midwest Case Study Using The Delphi Technique, Blake Colclasure

Journal of Research in Technical Careers

Community colleges have a strong history of providing vocational education and occupational training to meet changing workforce demands of local industries. In the Midwest, agricultural industries have expressed an expanding need for middle-skilled workers with postsecondary, prebaccalaureate credentials. The 21st century agricultural landscape has changed as a result of the need for efficiency and sustainability, and resulting emergent agricultural technologies. Community colleges will be integral to establishing a qualified agriculture workforce for entry-level, middle-skilled positions. This study utilized a modified Delphi approach to identify entry-level workplace competencies needed by graduates of a community college agriculture program. Delphi panel experts represented …

Can Soil Phosphorus Sorption Saturation Estimate Future Potential Legacy Phosphorus Sources?, A. N. Sharpley, K. R. Brye, J. M. Burke, L G. Berry, M. B. Daniels, P. Webb

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Various soil extraction methods are used to indicate plant available P in soil but do not account for soil specific sorption of subsequent applications of P. Thus, estimates of soil phosphorus sorption saturation (PSS; estimated from Mehlich-3 extractable P, Al, and Fe) have been used in conjunction with Mehlich-3 extractable soil phosphorus (M3P) to overcome these limitations. As less is known about the effect of land management on PSS than M3P under field conditions, the effect of field management on PSS was investigated for three pastures over 5 yr (2014-2018). Swine slurry was applied to two fields (Field 1 received …

Interaction Of Urea With Frequency And Amount Of Distillers' Grains Supplementation For Growing Steers On A High Forage Diet, Haley F. Linder

Department of Animal Science: Dissertations, Theses, and Student Research

Two studies were conducted to determine interactions of urea inclusion to a dried distillers grains plus solubles (DDGS) supplement fed at two amounts and two frequencies to steers on a high forage diet. In Exp. 1, 120 steers were fed individually for 84 d. Steers received ad libitum grass hay and 1 of 8 treatments. Supplement was fed either every day (D) or 3x/week (ALT), amount of supplement fed was 6.36 kg/week (LO) or 12.73 kg/week (HI), and contain either no urea (-U) or 1.3% urea (+U). Hay DMI and steer BW were measured. In Exp. 2, 8 ruminally cannulated …

Reducing Mowing Requirements In Home Lawn And Golf Course Turfgrass, Mark A. Keck

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Turfgrass systems are routinely managed by frequent mowing to increase aesthetics and function. Mowing is resource intensive with a high labor and energy demand. Reducing the number of mowings events in a growing season will decrease the labor and energy but may reduce quality as well. Previous work has looked at reducing mowing by changing the frequency and by using a plant growth regulator (PGR). Limited information is available about how to reduce mowing while maintaining acceptable quality. We looked at two different management practices to reduce mowing and maintain quality. The first study evaluated seven different mowing frequencies at …

Evaluating The Impact Of Grafting On Local Tomato Production In Nebraska, Raihanah Hassim

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Vegetable grafting has been known to improve plant production under both biotic and abiotic stresses. With an increase in interest among local growers towards grafting production, it is important to provide enough vegetable grafting information. Therefore, the objective of this study is to assess the impact of grafting, rootstock cultivar, and local conditions and management on the yield and quality of tomato across the diverse growing and environmental conditions, specifically in Nebraska. Three open-field and one limited growing condition study were conducted between 2018 and 2019 across Nebraska. In the open-field trial, two determinant fresh market tomatoes, ‘Nebraska Wedding’ and …

Effect Of Feed Additives And Toxic Elements On Swine Growth Performance, Nutrient Digestibility, Immune Function And Reproductive Performance, Richard A. Mudarra Hernández

Graduate Theses and Dissertations

To evaluate the effects of peptide in combination of zinc oxide (Zno) or acidifiers (Exp 1), and gossypol (G) from cottonseed meal (CSM) ( Exp 2&3) on growth performance, complete blood cell counts (Exp 1, 2&3), nutrient digestibility (Exp 1), plasma gossypol (Exp 2&3) and semen quality (Exp 3), weaned pigs (Exp 1), growing gilts (Exp 2) and growing boars (Exp 3) were randomly allotted to dietary treatments. Treatments for Exp 1 during phase 1&2 were: (1) Positive Control (PC), formulated to meet NRC (2012) nutrient requirements; (2) Negative control (NC), fish meal was reduced to achieve -0.13% SID lysine; …

Prospects For Enhancing The Market For Goat Meat Products: Analysis Of The 2019 Goat Meat Survey, Ashton M. Light

Graduate Theses/Dissertations

The objective of this study was to identify goat meat product attributes and sociodemographic drivers of consumers’ willingness to buy to goat meat products. To do so the study used a nationwide consumer survey on goat meat preferences. A binary logit model was used to examine the factors affecting willingness to buy. Results show that gender, age, region, primary shopper, and product attribute preference for quality, price, leanness, cholesterol, and freshness significantly affect consumer willingness to buy goat sausage, jerky, burger, and patties.

Discerning Competitive Vs. Facilitative Relationships Of Weeds On Forest Restoration Efforts At La Sal Del Rey, Tx, Mylen A. Arias

Theses and Dissertations

Dryland ecosystems need effective restoration strategies to address severe degradation. It is often assumed that voluntary forb weeds either compete with or have no effect on native seedlings. In contrast, theory and empirical work suggest a potential facilitative role for such forb weeds. We conducted a manipulative weed exclusion experiment at a semi-arid site in South Texas targeted for large scale forest restoration and subsequently dominated by early successional forb weeds to discern the net effect of these weeds on the growth and survival of target thornscrub tree and shrub seedlings. Overall, weed presence did not significantly affect seedling mortality …

Leadership Styles And Barriers To Leadership For Women In Agriculture: A Mixed Methods Study, Erica Ramsey Louder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Women are a growing demographic in agriculture, yet women holding positions in agricultural leadership is limited. This research sought to identify the ways women in agriculture lead by examining their leadership styles and the barriers they face as they strive to advance within their professions.

The results show that women are relationship-based leaders and that there are significant barriers that inhibit women’s advancement in agriculture. Many of these barriers are related to gender bias, self-perception, and life issues such as stress and workload.

Soil Management Systems To Overcome Multiple Constraints For Dryland Crops On Deep Sands In A Water Limited Environment On The South Coast Of Western Australia, David J. Hall, Stephen L. Davies, Richard W. Bell, Tom Edwards

Grain and Other Field Crops Research Articles

Deep sands on the south coast sandplain of Western Australia (WA) have multiple soil constraints including water repellence, high soil strength, low nutrient levels and subsoil acidity. The aim of the study was to test contrasting methods of managing water repellence and to assess their impacts on one or more soil constraints to crop production. These methods included seeding tyne design (knife point, winged points, paired row), soil wetting agent addition, strategic inversion tillage (rotary spading, mouldboard ploughing to 0.35 m) and clay-rich subsoil addition (170 t ha−1 with incorporation by spading to 0.20 or 0.35 m). Limesand (2 t …

Evaluating The Untapped Potential Of U.S. Conservation Investments To Improve Soil And Environmental Health, Andrea Basche, Katherine Tully, Nora L. Alvarez-Berrios, Julian Reyes, Laura Lengnick, Tabitha Brown, Jennifer M. Moore, Rachel E. Schattman, Lana Koepke Johnson, Gabrielle Roesch-Mcnally

Department of Agronomy and Horticulture: Faculty Publications

There is increasing enthusiasm around the concept of soil health, and as a result, new public and private initiatives are being developed to increase soil health-related practices on working lands in the United States. In addition, billions of U.S. public dollars are dedicated annually toward soil conservation programs, and yet, it is not well quantified how investment in conservation programs improve soil health and, more broadly, environmental health. The Environmental Quality Incentives Program (EQIP) is one of the major U.S. public conservation programs administered on privately managed lands for which public data are available. In this research, we developed a …

Managing Suckers Around Fruit Trees, Samuel Johnson, Teryl Roper, Xin Dai

All Current Publications

Many types of fruit trees produce suckers around the base of the tree. Crown suckers arise in the area immediately surrounding the tree trunk (Photo 1), and root suckers can arise from roots further away from the trunk. Not only are suckers around trees unsightly, but they can also harbor insect pests like wooly apple aphid and provide points of entry for diseases like fire blight. If suckers are profuse, they interfere with in-row weed management and can absorb systemic herbicides such as glyphosate. Some rootstocks used for fruit trees such as M.7 for apples and Mazzard for cherries are …

2020 Seedless Pickling Cucumber Variety Trial, Ben Phillips, Hilda Mcshane

Midwest Vegetable Trial Reports

A pickling cucumber variety trial was planted at the Saginaw Valley Research and Extension Center (43.399097, -83.694497, Frankenmuth, Michigan). Bejo (BJ), Nunhems (NU), and Rijk Zwaan (RZ) seed companies donated parthenocarpic (seedless) varieties for mechanical once-over harvest.

Market Trends In Food Consumption Expenditures Away From Home Prior To The Covid-19 Pandemic, Rebecca Weir

Undergraduate Economic Review

U.S. food consumption expenditures away from home increased from 19 percent of total food expenditures in 1955 to 48 percent in 2015. Simultaneously, female participation in the labor force grew by 52.7 million women from 35 to 57 percent, signifying increased opportunity cost for women to prepare meals at home. This research uses an ordinary least squares regression to examine socioeconomic factors influencing the rise in U.S. food consumption expenditures away from home in 2018. Results inform food production and service industries’ marketing strategies, and set the stage for whether a new pattern emerges in response to the COVID-19 pandemic.

Northern Giant Hornet (Vespa Mandarinia) And Yellow-Legged Hornet (Vespa Velutina), Potential Pests Of Honey Bees, Benjamin Andrew Powell

Agricultural Education

Exotic hornets present a significant threat to apiculture. Recent introductions of the yellow-legged hornet to Europe and the asian giant hornet to North America have made it critical that regulators, beekeepers and the general public be able to detect and identify these exotic hornets and to understand their biology to minimize the potential impacts to apiculture in South Carolina were they to be introduced.

2020 Nebraska Ballot Issues – Election Results, J. David Aiken

Cornhusker Economics

This publication provides educational information regarding the two constitutional amendments recommended by the Unicameral to Nebraska voters and the four citizen ballot initiatives on the November 2020 general election ballot.

Sustainable Management Of Groundwater In Louisiana, Dependra Bhatta

LSU Doctoral Dissertations

The common property nature of the Mississippi River Alluvial Aquifer (MRAA) results in the formation of a cone of depression in the southern portion of the aquifer encompassing Concordia parish, Louisiana. Excessive groundwater withdrawal and the resulting cone of depression formation have caused some wells to go dry and others to be affected by saltwater intrusion. The depleting groundwater stock can be managed optimally using different groundwater management policies. The findings of this dissertation are relevant to both policymakers and researchers to understand the effects of policies to keep the aquifer sustainable.

My dissertation is written in a three-essay format. …

Measured And Simulated Carbon Dynamics In Midwestern U.S. Corn‐Soybean Rotations, C Dold, K M. Wacha, T J. Sauer, J L. Hatfield, J H. Prueger

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

Corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) production dominate Midwestern U.S. agriculture and impact the regional carbon and nitrogen cycles. Sustaining soil carbon is important for corn‐soybean production (CS); however, quantifying soil carbon changes requires long‐term field measurements and/or model simulations. In this study, changes in soil organic (SOC), inorganic (SIC), and total (TC) carbon; pH; total nitrogen (TN); and net ecosystem production (NEP) were measured in a conventional corn‐soybean rotation in central Iowa. Soil samples (n = 42; 0–120 cm depth) were collected from two adjacent fields in 2005 and 2016. Eddy‐flux stations set up in …

The Impact Of Hemp Cropping Systems On Soil Quality In Western Kentucky, Jack Eaker

Scholars Week

Recently, hemp farming systems are increasingly popular in Kentucky replacing tobacco cropping systems. However, the study on the impacts of hemp cropping on soil properties is rarely conducted, resulting in limited data on soil’s behavior/changes under these management practices. Therefore, the objective of this study was to determine soil characteristics including compaction, acidity level, moisture level, and water retention. The measurements were collected from three different hemp fields, three crop rotation studies ( in 2020 - corn, soybean and tobacco) and a bare field adjacent to these fields. All fields are located at Murray State University West Farm, Calloway County, …

Seed Quality And Dormancy Of Hemp (Cannabis Sativa L.), Sabry G. Elias, Yea-Ching Wu, David C. Stimpson

Journal of Agricultural Hemp Research

Hemp has great potential as cash crop for growers in the US because of its multiple uses in food, pharmaceutical, and industrial products. Seed quality and dormancy research had been put off for decades. The indeterminate flowering pattern of hemp results in harvesting seeds with varying maturity levels, affecting their quality. The objectives of this study were to: 1) investigate the differences in quality of seeds harvested from different locations on the same plant, 2) determine suitable viability and vigor tests for evaluating hemp seeds, and 3) examine the extent of dormancy in newly harvested seeds and develop a dormancy-breaking …

Beginning And Small Acreage Farms: Nonmotorized Tool Selection, Sheriden M. Hansen, Melanie Stock, Dan Drost, Katherine Wagner

All Current Publications

Farming on 2 acres or less can be challenging, especially when considering equipment selection. It is important to carefully consider the equipment options available. Tools should be cost-effective, task and operation appropriate, of high quality and durability, and provide labor savings. Appropriate equipment contributes to farm viability by enhancing labor efficiency and crop quality. This fact sheet briefly describes equipment beginning farmers commonly need or use on small farms.

Evaluation Of Louisiana Farm To School Programming: Harvest Of The Month And Local Food Procurement, Arin M. Shaffer

LSU Master's Theses

Farm to school is a growing movement that is beginning to draw serious interest in different parts of the United States due to its ability to connect communities with their local producers while providing many benefits. Farm to school entails three main components: school gardening, education and curriculum, and local food procurement. The farm to school movement is relatively new to the state of Louisiana and very little research has been conducted to evaluate the impact of the farm to school programs on local food procurement and the effect on school food environments. Case studies of three Louisiana parish school …