Agronomy and Crop Sciences Commons^™

Evaluating A Precision Sprayer For Detecting Weeds And Spraying Herbicides In Real Time (Spot Spray) For Weed Management In Corn And Soybean, Adam Eric Leise

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

Herbicide sprayers are becoming larger and more efficient in applications in crop fields. A precise and efficient herbicide application is advantageous in effective weed control. New precision sprayers were introduced in hopes of reducing the amount of herbicide applied. Greeneye Technology and John Deere have developed precision sprayers for the detection of weeds in crop fields, which come equipped with a dual tank system that allows for two different herbicides to be separated from tank to tip. The objectives of this study were to evaluate the broadleaf and grass weed control efficacy of spot spray (SS) technology when applied in …

Unmanned Aerial Vehicle (Uav)-Based High-Throughput Phenotyping For Maize Improvement, Eric T. Rodene

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Modern breeding programs rely heavily on efficiently screening large numbers of genotypes for agronomic traits, such as disease resistance, drought tolerance, and yield. Identifying the genetic loci or genes associated with these traits using GWAS or functional analyses will benefit future plant breeding efforts seeking to incorporate these traits into new crop varieties, whether through conventional breeding or gene editing techniques. Unmanned aerial vehicle (UAV)-based image data has been increasingly used for this task, as it allows entire test plots to be quickly and cost-effectively phenotyped. In my research, I have developed methods to improve the accuracy of machine learning …

Exploring Producers' Willingness To Pay For Ecosystem Services: Three Essays On Soil Health, Location Preferences, And Cover Crop Adoption, Kaouter Essakkat

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

This dissertation comprises three essays: one assessing Midwest producers' willingness-to-pay (WTP) for soil health-enhancing ecosystem services (ES), another examining the impact of policy implementation locations on WTP, and a third identifying factors influencing producers' adoption of cover crops (CC).

The first essay pioneers the understanding of agricultural producers’ valuation of soil health-associated ES amid growing concerns of soil degradation due to agricultural intensification. Using a discrete choice experiment, this study assesses producers’ WTP for a policy that incentivizes ES provision, specifically improved water quality, carbon sequestration, and enhanced crop yield. Surveying producers across Iowa, Kansas, and Nebraska, our results show …

Assessment Of Foam Decontamination In Tomato Washing Process, Basim M. Alohali

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The work of the dissertation investigated the efficacy of foam-based decontamination treatments to enhance microbial safety in Roma tomatoes, specifically targeting natural microflora and Salmonella contamination. Growing concerns over foodborne illnesses linked to fresh tomatoes and the limitations of conventional decontamination techniques, such as organic matter built-up and limited microbial reduction, are addressed. The primary objectives were to characterize the physiochemical properties of foams formed using various concentrations of Tween 20 (T20) and sodium dodecyl sulfate (SDS) with and without the addition of sodium hypochlorite (NaOCl) and peracetic acid (PAA), compare the efficacy of foam and traditional dump tank (DT) …

Integrating Remote Sensing And Machine Learning To Determine Past, Current And Future Crop Water Use From The Nubian Sandstone Aquifer System, Moaz Ishag

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The agriculture sector is a significant consumer of water, and sustainable water use begins with monitoring irrigated land. Delineating irrigated land supports decision-makers and promotes the sustainable use of this crucial resource. This study focuses on the Nubian Sandstone Aquifer System (NSAS), the largest aquifers in the world, which spans Egypt, Sudan, Libya, and Chad. The study aims to: 1) quantify the increase in irrigated hectares (both pivot and non-pivot) from 2000-2001 to 2023-2024; 2) identify major irrigated crop types and their water requirements; and 3) quantify groundwater crop water use from the NSAS using remote sensing via the Google …

Assessing Soil Properties For Optimized Irrigation Development In Sudan, Northern Africa, Suhib Hamid, Derek M. Heeren, Aaron R. Mittelstet, Saleh Taghvaeian, Randall S. Ritzema

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Sustainable irrigation methods maximize agricultural productivity in Northern African countries like Sudan. This project evaluates soil properties to develop optimized irrigation strategies for Sudan's arid and semi-arid climate. Assessing soil characteristics such as texture, infiltration rates, and nutrient content informs the selection of modern irrigation systems. Data from 3,192 locations, collected using GPS and ring infiltrometers for infiltration rates, alongside laboratory analyses for soil properties, were employed. A ranking system determined suitable irrigation systems for specific soil classes, considering factors like slope, wind, crop tolerance, available water capacity (AWC), drainage, germination, capital cost, labor cost, maintenance, and evapotranspiration (ET). The …

Investigating The Abilities Of Potentially Beneficial Bacteria For Increasing Nitrogen-Use Efficiency In Maize, Lexie R. Foster

School of Biological Sciences: Dissertations, Theses, and Student Research

Global agriculture relies heavily on the use of synthetic nitrogen fertilizer to meet the current global food demand. Unfortunately, the average nitrogen-use efficiency (NUE) of maize (Zea mays) is approximately 50 percent. Improving the NUE of maize is essential for meeting the growing global food demand while also decreasing the negative environmental impacts caused by losses of nitrogen fertilizer due to runoff and volatilization. Harnessing the symbiotic relationship between plants and the soil microbiome may be one method for increasing the NUE in crops such as maize. In the present study, a set of potentially beneficial bacterial species …

Triticale As A Source Of Resistance To Wheat Streak Mosaic Virus And Triticum Mosaic Virus, Marcos Winicius Goncalves De Souza

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

Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) present a great threat to wheat production in the Great Plains area of the United States due to the loss of photosynthetic area causing reductions in crop yields. Effective control of these viruses is limited to a few available strategies including controlling volunteer wheat and using currently identified resistant genes to both the vector and viruses. While effective, these genes show temperature sensitivity and yield drag, and evidence that the vectors and viruses can overcome them has been found. Thus, new methods of genetic resistance are urgently needed. Field observations …

Tissue‑ And Time‑Dependent Metabolite Profiles During Early Grain Development Under Normal And High Night‑Time Temperature Conditions, Nathan Abshire, Andrew L. Hauck, Harkamal Walia, Toshihiro Obata

Department of Agronomy and Horticulture: Faculty Publications

Background Wheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to various environmental conditions, including high night temperatures (HNTs). Flag leaves and seed-associated bracts (glumes, awn, palea, and lemma) provide nutrients to the developing seed. However, the specific metabolic roles of these tissues are uncertain, especially their dynamics at different developmental stages and the time in a day. Tissue- and time-dependent metabolite profiling may hint at the metabolic roles of tissues and the mechanisms of how HNTs affect daytime metabolic status in early grain development. …

Fabrication Of A Low-Cost Drum Seeder For Paddy, Muhammad Rashed Al Mamun, Md Rejaul Karim, Md Towfiqur Rahman, Md Janibul Alam Soeb, Md Imranul Alam

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rice is a staple food crop. Bangladesh produces it extensively which raised the nation into the fourth-largest rice-grower in the world. Transplanting or direct seeding is a major task in rice cultivation where the manual transplanting method requires a huge labor cost which is beyond control in a peak season. Although mechanical rice transplanters become popularization land preparation and seedling rising as a pre transplanting task is costly and labor-intensive. On the other hand, manual broadcasting and machine seeding direct method still exist due to the above method’s problem. Considering spacing accuracies for intercultural operation, drum seeders are an easy …

Plas 439: Organic Farming And Food Systems Faculty-Led Inquiry Into Reflective Scholarly Teaching Benchmark Portfolio, Christian Stephenson

UNL Faculty Course Portfolios

Organic Farming and Food Systems is a senior and graduate level course for students in the Department of Agronomy and Horticulture. This course was previously offered but has been significantly modified as I have taken on responsibility for the course. Goals for the course include student comprehension of the methods of organic and regenerative farming and the impacts of those methods on economic, environmental, and social sustainability. An additional goal is to build student competency in the evaluation of primary, secondary, and tertiary information resources and critical thinking surrounding issues in food production. Assessment for the course was through diverse …

Cereal Rye Cover Crop Termination At Or Before Soybean Planting Has Minimal Effect On Soybean Yield Across The Midwestern Us, Tatiane Severo Silva, Spyridon Mourtzinis, Anthony Justin Mcmechan, Gabriela Inveninato Carmona, Bruce D. Potter, Kelley J. Tilmon, Louis S. Hesler, Nicholas J. Seiter, Robert Wright, Shannon L. Osborne, Thomas E. Hunt, Shawn P. Conley

Department of Entomology: Faculty Publications

Context: Interest is growing among farmers in the Midwestern US region in the potential benefits of establishing cereal rye (Secale cereale L.) as a cover crop. However, they are concerned about the implications and potential trade-offs due to this practice. Objective: We aimed to evaluate the effects of cereal rye cover crop termination at or before soybean planting on soybean (Glycine max [L.] Merr.) seed yield. Methods: Field experiments were conducted from 2019 to 2021 across 28 location-years in the Midwestern US. Treatments consisted of no cereal rye, cereal rye termination before soybean planting, and termination at planting. …

Adopting Yield-Improving Practices To Meet Maize Demand In Sub-Saharan Africa Without Cropland Expansion, Fernando Aramburu-Merlos, Fatima A. M. Tenorio, Nester Mashingaidze, Alex Sananka, Stephen Aston, Jonathan J. Ojeda, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Maize demand in Sub-Saharan Africa is expected to increase 2.3 times during the next 30 years driven by demographic and dietary changes. Over the past two decades, the area croppedwithmaize has expanded by 17million hectares in the region, with limited yield increase. Following this trend could potentially result in further maize cropland expansion and the need for imports to satisfy domestic demand. Here, we use data collected from 14,773 smallholder fields in the region to identify agronomic practices that can improve farm yield gains. We find that agronomic practices related to cultivar selection, and nutrient, pest, and crop management can …

Evaluating The Yield Of Surviving Plants From Early-Season Hail Damage In Corn: A Field Survey, I. P. Lisboa, Christopher A. Proctor, R W. Elmore, A. J. Mcmechan, N. D. Mueller, J. Wilson, G. Zobeck, Aaron Nygren, A. Bastidas, Osler Ortez

Department of Agronomy and Horticulture: Faculty Publications

Economic losses due to hailstorms acrossUS corn fields occur every year.Hailstorms result in leaf defoliation, decreasing photosynthetic area and impairing carbon assimilation and crop yield for all corn (Zea mays L.) development stages. However, more attention is often given to stand reductions rather than damage to stems or leaf defoliation. During the 2014 growing season, a natural hail event affected many areas of eastern Nebraska. Twelve affected corn fields were surveyed and included in this study. An injury score scale (1–5) was developed based on various injury and severity levels before the V6 (6-leaf corn growth stage) (six-collared leaves). …

Natural Variation In Lonely Guy-Like 1 Regulates Rice Grain Weight Under Warmer Night Conditions, Jaspreet Sandhu, Larissa Irvin, Anil Kumar Chandaran, Shohei Oguro, Puneet Paul, Balpreet Dhatt, Waseem Hussain, Shannon S. Cunningham, Cherryl O. Quinones, Argelia Lorence, Maria Arlene Adviento-Borbe, Paul E. Staswick, Gota Morota, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Global nighttime temperatures are rising at twice the rate of daytime temperatures and pose a challenge for rice (Oryza sativa) production. High nighttime temperature (HNT) stress affects rice yield by reducing grain weight, size, and fertility. Although the genes associated with these yield parameters have been identified and characterized under normal temperatures, the genetic basis of grain weight regulation under HNT stress remains less explored. We examined the natural variation for rice single grain weight (SGW) under HNT stress imposed during grain development. A genome-wide association analysis identified several loci associated with grain weight under HNT stress. A …

First Record Of The Invasive Chenopodium Aphid, Hayhurstia Atriplicis (Linnaeus, 1761) (Hemiptera: Aphididae), In Colombia, Takumasa Kondo, Roberto Rosero, Jackeline Gaviria

Insecta Mundi

The chenopodium aphid, Hayhurstia atriplicis (Linnaeus, 1761) (Hemiptera: Aphididae), is reported for the first time in Colombia. The aphid was found on the aerial parts of the quinoa plant, Chenopodium quinoa Willd. (Amaranthaceae), especially on the leaves, in five municipalities in the department of Cauca, Colombia. Brief information on its natural enemies, distribution and biology is provided. This is the only aphid in Colombia known to cause malformations on the leaves of quinoa plants. In South America, this aphid has been found previously only in Ecuador, where it was reported for the first time in 2023 based on specimens collected …

On-Farm Nitrogen And Irrigation Management Strategies To Protect Groundwater Quality In The Bazile Groundwater Management Area, Arshdeep Singh

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

Increasing groundwater nitrate (NO₃-N) contamination has raised significant environmental and health concerns in the irrigated sandy soils of Nebraska. Four studies were conducted to evaluate the impact the impact of 1) static (NE Yield Goal) vs. dynamic nitrogen (N) recommendations tools (Maize-N, Canopy Reflectance Sensing, Granular, and Adapt-N), 2) three N (optimum, suboptimum, and low) and irrigation rates (farmer’s full irrigation (FIT), 80% FIT, and 60% FIT), 3) conventional N sources vs. enhanced efficiency fertilizers (EEFs), and 4) multiple N splits (2, 3, 4, and 5-N splits) on agronomic (maize yield), environmental (NO3-N leaching), and economic returns (return …

In-Field Optimization Of Soil Water Parameters For Irrigation Scheduling, Ishani Lal

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

Several precision technologies are being developed to assist farmers in informed irrigation decision-making. These technologies aim to enhance irrigation water efficiency, check overirrigation, boost crop water productivity, and promote the sustainable utilization of water resources. We hypothesize that soil moisture parameters used in irrigation decision tools need to be validated to best represent the correct state of soil moisture in the field. This is an important factor that affects the accuracy of the irrigation recommendations forecasted by the decision support tools. In this research, we evaluated different methods of estimating field capacity (FC) and wilting point (WP) to optimize soil …

Establishment Of Wildflower Islands To Enhance Roadside Health, Ecological Value, And Aesthetics, Jackson Ebbers

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

Roadsides provide an abundant opportunity to increase connectivity of fragmented landscapes with diminishing floral resources for pollinating insects. The ecological value of these sites is often overlooked as quality habitat for pollinators, particularly monarch butterflies, which have been experiencing severe declines due to loss of habitat and loss of milkweeds that provide food for their larvae. Land managers across the nation are realizing the potential of roadsides to provide high quality floral resources for the benefit of insects and other wildlife. Current wildflower seed mixes used by state transportation departments are often low diversity and may only be implemented following …

Impact Of Plant Defenses And Aphid-Associated Microbes In Modulating Sorghum–Sugarcane Aphid Interactions, Edith Ikuze

Department of Entomology: Dissertations, Theses, and Student Research

Sorghum (Sorghum bicolor) is a vital cereal crop globally, facing challenges from invasive pests such as the sugarcane aphid (SCA; Melanaphis sacchari). To elucidate mechanisms of sorghum resistance to SCA, we examined the role of plant defenses and the influence of aphid-associated microbes in modulating sorghum defenses. Lignin is a complex heterogenous polymer present in nearly all plant cell walls that plays a critical role in protecting plants from various stresses. In this study, we investigated the role of the caffeoyl coenzyme-A O-methyltransferase (CCoAOMT), one of the core enzymes in monolignol biosynthesis pathway that leads to lignin …

Irt-Based Irrigation Scheduling And Dry Bean Crop Water Productivity Under Different Irrigation Scenarios In The Nebraska High Plains, Angie Gradiz

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Irrigation plays a critical role for crop production in western Nebraska of the United States, where crop evapotranspiration often exceeds in-season precipitation. This study investigated the impacts of different irrigation treatments on yield and key physiological parameters of dry edible beans grown in semi-arid western Nebraska during the 2022-2023 growing seasons. Seven irrigation levels (0%, 25%, 50%, 75%, 100%, 125%, 150%) of the fully irrigated treatment (FIT), were applied using a Variable Rate Irrigation (VRI) Linear-Move Sprinkler System. Additionally, an eighth treatment was scheduled based on measurement from infrared radiometry thermometers (IRT) to evaluate the performance of the two-source energy …

Using Annual Forages To Replace Declining Cool-Season Grass Pasture Availability, Jonathon Matthew Jenkins

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

As land area in grain crop production increases in the US Midwest, perennial pasture availability decreases but the demand increases. Matching the seasonal growth patterns of C₃ and C₄ plant species to grow forages that are complementary allows producers to fill production gaps in otherwise monoculture systems and possibly increase overall productivity. One way to fill the forage production gap of C₃ grass dominated pastures is by producing a warm-season, annual forage in a separate field. However, with continual reductions in land availability, this may not be an option. Using two studies, our objectives were to improve …

Evaluation Of Essential Oils And Their Major Components For Disease Resistance, Serkan Tokgöz

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Essential oils (EOs) are natural hydrophobic compounds, which are highly complex, typically comprising 20 to 60 constituents, with two or three main components making up 20% to 95% of their composition, alongside other minor constituents. Research has firmly established the potent antibacterial and antifungal properties of EOs and their primary components. To assess their efficacy, one EO, nutmeg oil, and seven main components, including safrole, toscanol, safraleine, cinnamaldehyde, carvacrol, carvone, and thymol, were tested against four economically significant fungal pathogens (Alternaria solani, Fusarium graminearum, Rhizoctonia solani, and Sclerotiorum sclerotiorum), one oomycete pathogen (Phytium ultimum …

Next-Generation Crop Monitoring Technologies: Case Studies About Edge Image Processing For Crop Monitoring And Soil Water Property Modeling Via Above-Ground Sensors, Nipuna Chamara

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Artificial Intelligence (AI) has advanced rapidly in the past two decades. Internet of Things (IoT) technology has advanced rapidly during the last decade. Merging these two technologies has immense potential in several industries, including agriculture.

We have identified several research gaps in utilizing IoT technology in agriculture. One problem was the digital divide between rural, unconnected, or limited connected areas and urban areas for utilizing images for decision-making, which has advanced with the growth of AI. Another area for improvement was the farmers' demotivation to use in-situ soil moisture sensors for irrigation decision-making due to inherited installation difficulties. As Nebraska …

Linking Reactive Nitrogen Species Within The Vadose Zone With Surface Irrigation, Kaitlyn Richards

Honors Program: Senior Projects (Public)

This study investigated the relationship between irrigation methods and the mobilization of nitrogen in the vadose zone, focusing on soil properties, water dynamics, and nitrogen species distribution. Data collected from dryland and pivot-irrigated soil cores reveal distinct patterns in water content, bulk density, soil texture, pH, conductivity, and nitrogen concentrations. Results indicated that water content has a major influence in nitrogen availability and microbial activity. Nitrate-N and ammonium-N concentrations varied between dryland and pivot soils, with notable disparities observed. In dryland soils, nitrate-N concentrations varied widely across depth intervals, with notable accumulation in deeper layers, while ammonium-N concentrations exhibited a …

Overexpression Of Msdreb1c Modulates Growth And Improves Forage Quality In Tetraploid Alfalfa (Medicago Sativa L.), Yangyang Zhang, Zhen Wang, Fan Zhang, Xue Wang, Yajing Li, Ruicai Long, Mingna Li, Xianyang Li, Quanzhen Wang, Qingchuan Yang, Junmei Kang

Department of Agronomy and Horticulture: Faculty Publications

DREB has been reported to be involved in plant growth and response to environmental factors. However, the function of DREB in growth and development has not been elucidated in alfalfa (Medicago sativa L.), a perennial tetraploid forage cultivated worldwide. In this study, an ortholog of MtDREB1C was characterized from alfalfa and named MsDREB1C accordingly. MsDREB1C was significantly induced by abiotic stress. The transcription factor MsDREB1C resided in the nucleus and had self-transactivation activity. The MsDREB1C overexpression (OE) alfalfa displayed growth retardation under both long-day and short-day conditions, which was supported by decreased MsGA20ox and upregulated MsGA2ox in the OE …

Evaluating Consistency Across Multiple Neospectra (Compact Fourier Transform Near-Infrared) Spectrometers For Estimating Common Soil Properties, Sadia M. Mitu, Colleen Smith, Jonathan Sanderman, Richard R. Ferguson, Keith Shepherd, Yufeng Ge

Department of Agronomy and Horticulture: Faculty Publications

Rapid and cost-effective techniques for soil analysis are essential to guide sustainable land management and production agriculture. This study aimed at evaluating the performance and consistency of portable handheld Fourier-transform near-infrared spectrometers and the NeoSpectra scanners in estimating 12 common soil physical and chemical properties including pH; organic carbon (OC); inorganic carbon (IC); total nitrogen (TN); cation exchange capacity (CEC); clay, silt, and sand fractions; and exchangeable potassium (K), phosphorus (P), calcium (Ca), and magnesium (Mg). A diverse set of samples (n = 600) were retrieved from a national-scale soil archive of the Kellogg Soil Survey Laboratory of USDA-NRCS …

Accurate Measurement Of Field Size Is Essential For Analysis Of Smallholder Survey Data, Rica Joy Flor, Shen Yuan, Gonzalo Rizzo, Fahmuddin Agus, Anny Ruth P. Pame, Akhara Ouk, Rathmuny Then, Sokheng Keo, Virender Kumar, Particio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Context: Agronomic surveys play a vital role in identifying on-farm yield constraints and opportunities to increase productivity, input-use efficiency, and farmer profit. These surveys typically rely on farmer-reported data, where crop yield and applied inputs per hectare are estimated based on farmer-reported total harvested output and applied inputs per field and associated field size. At question is how accurate field size is, which is vital in the case of smallholders as small inaccuracies can lead to large biases in estimated yield and inputs.

Objectives: The goals of this study are to assess current approaches to determine field size …

Phenotypic Diversity For Morpho-Agronomic Traits In The Us Proso Millet (Panicum Miliaceum L.) Core Collection, Santosh G. Rajput, Rituraj Khound, Dipak K. Santra

Department of Agronomy and Horticulture: Faculty Publications

Proso millet (Panicum miliaceum L.) is a short-season annual crop known for high water-use efficiency and drought tolerance. The low water requirement makes this ancient grain an excellent rotational crop for the winter wheat-based dryland cropping system in theHigh Plains of theUnited States. The genetic base of the commonly grown US cultivars is very narrow. Assessment of proso millet germplasm for agronomic traits is essential for its efficient utilization in the genetic improvement of this crop. The objectives of this study were to (1) characterize the US proso millet germplasm based on nine important morpho-agronomic traits and (2) classify …

Predicting The Potential Distribution Of Pseudococcus Longispinus (Targioni-Tozzetti) (Hemiptera: Pseudococcidae) In South Korea Using A Climex Model, Su Bin Kim, Soo-Jung Suh

Insecta Mundi

Pseudococcus longispinus (Targioni-Tozzetti) (Hemiptera: Pseudococcidae) is a widely-distributed pest that feeds on many economically important hosts, particularly tropical fruits and ornamentals. The potential distribution of this mealybug pest in South Korea remains a primary concern because of its high incidence of interceptions screened during inspection. Hence, this species prompted a modelling effort to assess its potential risk of introduction. Potential risk maps were developed for this pest with a CLIMEX model based on occurrence records under environmental data. The potential distribution of these pests in South Korea in the 2020s, 2050s and 2090s was projected based on the RCP 8.5 …