Agronomy and Crop Sciences Commons^™

Response Of Soybean To Variable Irrigation Levels In Eastern Nebraska Using The Aquacrop Model, Anmol Singh

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

AquaCrop was calibrated and validated for soybean [Glycine max (L.) Merr.] using 19 irrigation treatments from five years using data from field experiments. The model accurately simulated canopy cover (CC), soil water content (SWC), and grain yield, with overall validation nRMSE values of 12%, 7%, and 7%, respectively. The overall validation nRMSE for SWC in individual 30-cm soil layers was comparatively higher, at 19%. The model was subsequently applied for long-term simulations (2010–2024) to estimate soybean yield and water requirements for two dominant soil types, Yutan silty clay loam and Tomek silt loam under three irrigation levels - rainfed, …

Use Of High-Throughput Phenomics With And Without Fungicide As A Wheat Breeding Tool, Gerardo Ivan Rivera Collazo

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

Wheat (Triticum aestivum) is an important food staple for many countries around the world and current consumption and production data demonstrate a production deficit. Breeders are challenged to help close this gap in production by selecting better cultivars with improved yields. Several methods aim to accelerate the breeding process to reduce the time required for releasing an elite variety. One of the main breeding bottlenecks is the lack of fast and reliable phenotypic data acquisition that could dissect physiological and morphological plant data. High-throughput remote sensing could have the potential to reduce this bottleneck by streamlining data acquisition, …

Primary Investigation Of Rice-Fish Co-Culture: Investigating The Feasibility Of Raising Fish In Flooded Rice Paddies In The Southern Usa, Yulin Jia, Aaron K. Jackson, Bartholomew Green, S. Adam Fuller, Heather Box, Laduska Sells, Candis Ray, Paxton Harper, Brennan Smith

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

With limited land and water resources available it has become critical to maximize output for agricultural products while maintaining sustainable farming practices. Ricefish co-culture can be used to maximize limited land and water resources for production of rice and fish concurrently and reduce the need of chemical inputs. While rice-fish co-culture has been practiced in Asia for centuries, very few studies have examined the feasibility and economic impact of rice fish co-culture in the U.S.A. Two studies were conducted in Stuttgart, Arkansas, U.S.A. from 2023-2024 to investigate the suitability of raising Koi carp in flooded rice paddies with a sushi …

Mitigating Nitrogen Losses: The Role Of Enhanced Efficiency Fertilizers In Sustainable Corn Production, Dipesh Giri

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

Nitrogen (N) is essential for crop production, but its inefficient use often leads to environmental losses through nitrate leaching, ammonia volatilization, and nitrous oxide (N₂O) emissions. Enhanced efficiency fertilizers (EEFs), such as nitrification inhibitors (NIs) and urease inhibitors (UIs), have been developed to minimize these losses and improve nitrogen use efficiency (NUE). This research combined a multi-year field experiment and a controlled laboratory study to evaluate how dual-inhibitor fertilizers compare to conventional urea and single-inhibitor formulations in Nebraska cropping systems. The main objective was to understand how nitrogen inhibitors influence N availability, crop performance, and nitrogen losses across different environmental …

Improving Nitrogen Management And Corn Productivity Through Enhanced Efficiency Fertilizer And Cover Crop Integration In Nebraska Cropping Systems, Madhusudhan Adhikari

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

Effective nitrogen (N) management is vital for sustaining corn yield and reducing environmental impacts in Nebraska cropping systems. Three field studies were conducted to evaluate the impact of 1) fertilizer type (anhydrous ammonia [AA] with nitrification inhibitor: enhanced efficiency fertilizer [EEF] or AA without EEF) and N application timing (pre-plant vs. split with side-dress UAN) on in-season soil N availability, crop response, nitrous oxide (N₂O) emissions, residual soil N and N use efficiencies (NUEs); 2) winter cover crop (CC) species and crop rotation variability on CC biomass production, N uptake, soil N dynamics, and cash crop performance in …

Extending Cover Crop Growing Window To Improve The Health Of Environmentally Sensitive Soils, Noshin Ara Tunazzina

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

Sloping and sandy soils are highly susceptible to degradation. The health of these soils could be improved with cover crops (CCs). However, CC effectiveness in improving soil health mainly depends on CC biomass production, which is often low in temperate regions. The question is: how can we increase CC biomass production? Lengthening the CC growing window can be a potential strategy. This study assessed how 1) interseeded and terminated early (2-3 weeks before crop planting) CC, 2) interseeded and terminated late (at crop planting) CC, 3) drilled (after harvest) and terminated early CC, 4) drilled and terminated late CC, and …

Evaluating Risk And Return Of Corn And Soybean Marketing Strategies Using Monte Carlo Simulation Methods, Johanna Ilves

Department of Agricultural Economics: Dissertations, Theses, and Student Research

This study evaluates the performance of pre-harvest marketing strategies for corn and soybeans, using Monte Carlo simulation techniques. Given the increasing volatility in commodity prices and the evolving landscape of agricultural markets, producers face growing challenges in developing effective marketing plans that manage risk and enhance profitability. This thesis examines thirteen marketing strategies from 2008 to 2024, including benchmark harvest-only sales and various pre-harvest futures contract approaches. Historical futures price data for December corn and November soybean contracts were used to simulate 1,000 marketing outcomes per strategy per year, capturing a broad range of market conditions. Key performance indicators such …

Landscape Effects On The Beneficial Arthropod Community In Agriculturally Dominated Environments, Hannah E. Stowe

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

Ecosystem services in agriculturally dominated regions rely, at least in part, on arthropods. Environment and biodiversity influence beneficial arthropods in population size, community structure, diversity, and ecosystem service provisioning. Predation is among the most important services provided by arthropods in agroecosystems. Understanding what alters predation and predator activity can support the successful application of biological control and, more broadly, integrated pest management. Land use and edge adjacency, field characteristics, landscape, seasonality, and diel period all alter predatory behavior. Crop fields dominate Nebraska agroecosystems, although interspersed perennial grasslands persist through the Conservation Reserve Program (CRP). Such grasslands supply crucial resources and …

Gene Editing Approaches To Improving Grain Amino Acid Profiles In Maize And Sorghum, Joseph Preston Hurst

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

Maize grain is deficient in lysine. While the opaque2 mutation increases grain lysine, o2 is a transcription factor that regulates a wide network of genes beyond zeins, which leads to pleiotropic and often negative effects. Additionally, the drastic reduction in 19kDa and 22kDa alpha-zeins causes a floury kernel, unsuitable for agricultural use. Sorghum, closely related to maize, has a similar lack of lysine that can be corrected with prolamin alteration and also subject to the same deleterious kernel texture. CRISPR/cas9 gives researchers the ability to directly target genes of interest. In this research, gene editing was used to specifically target …

Mechanisms Of Perennial Sorghum Resistance To Sugarcane Aphid Infestation, Esha Kaler

Department of Entomology: Dissertations, Theses, and Student Research

Sorghum, Sorghum bicolor (L.) Moench, the fifth most-grown cereal crop in the world, is a versatile crop, grown across different agro-ecological regions. Sorghum has numerous uses ranging from food and forage purposes to biofuel production. Sugarcane aphid (SCA; Melanaphis sacchari) is a major threat to sorghum production, accounting for 50% to 100% yield loss under heavy infestations. Perennial sorghum can be a sustainable and climate-resilient alternative to the current cereal farming systems. The development of perennial sorghum offers numerous benefits, such as reduced economic inputs, more carbon sequestration, better soil health, and sustainable yields. We employed host plant resistance …

Integrating Genomic And Phenomic Breeding Tools For Wheat Stem Sawfly Resistance In Hard Winter Wheat, Sydney E. Graham

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

The wheat stem sawfly (WSS; Cephus cinctus) is an insect pest that affects wheat (Triticum aestivum) in the Northern Great Plains. This pest causes stem cutting that makes the plants susceptible to lodging and results in up to 30% yield loss. The primary management strategy for producers is utilizing host plant resistance, for which the main trait is stem solidness. This trait increases the pith thickness and provides resistance to the WSS by increasing larval mortality and reducing stem cutting. While stem solidness is largely controlled by a known major gene (SSt1), the phenotypic expression is also …

Understanding Pre-Harvest Hedging Behavior And Basis Forecasting: The Role Of Information In Grain Marketing, Iyore Eronmwon

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

This dissertation examines decision-making under risk in grain marketing, focusing on how information influences behavior, attitudes toward accessible information, and methods for forecasting commodity basis. Through three essays, it explores the impact of information on hedging decisions, the determinants of information-seeking behavior, the extent to which students can serve as proxies for farmers in risk experiments, and the effectiveness of different forecasting approaches for commodity basis.

The first essay examines the impact of information on pre-harvest grain marketing hedging decisions and grain marketing information-seeking behavior. Specifically, it evaluates two types of information hypothesized to influence decision-making: expected cost of production …

Where Is Your Crop Insurance Agent? Understanding The Geographical Distribution Of Agents, Cory Walters, Nathan Delay

Cornhusker Economics

Following the modifications to the Standard Reinsurance Agreement (SRA) in 2010, there was limited understanding of the impact of policy changes on agent availability. Our objective is to construct a model of the equilibrium supply of crop insurance agents and to test hypotheses regarding the factors influencing agent concentration, such as commissions, competition, and risk. We developed a theoretical equilibrium model of the federal crop insurance market, which encompasses three tiers: insurance companies, agents, and farmers. The model incorporates key features of the federal program, including government-set premiums and the stipulation that agents cannot refuse coverage or modify premiums for …

Field Calibration Of A Time Domain Reflectometry Sensor For Water Content Measurement In Soils With Low Content Of Coarse Fragments, Rehnuma Maisha, Dean Steele, Aaron L. M. Daigh, Derek M. Heeren, Trenton E. Franz

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Comparison of soil water sensors for irrigation scheduling requires an accurate reference measurement. An Acclima TDR-310H soil water content sensor was calibrated and validated for sand, loamy sand, clay loam, sandy clay loam, and sandy loam soils. In 2021, sensor readings and soil samples were collected in the same sensor volume at depths of 15 and 46 cm at three irrigated field sites with five stations each. Gravimetric water content, bulk density, and volumetric water content (θv) were determined in the lab. The root mean square error was 0.032 cm³ cm⁻³, which was within acceptable limits. The …

Evaluation Of The Global Durum Panel (Triticum Turgidum Ssp. Durum) For Wheat Streak Mosaic Virus Resistance, Winter Survival, And Seed Characteristics, Megan Engel

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

The majority of durum wheat (Triticum turgidum spp. durum; AABB; 2n=4x=28) is predominantly grown in the northern Great Plains of the United States, and is used in the production of semolina, a coarse flour that makes pasta and couscous. Durum has been widely regarded for being more tolerant to abiotic stress, due to its ability to withstand drought and high temperatures. In this thesis, we conducted greenhouse, field, and lab studies, for the traits wheat streak mosaic virus (WSMV), winter survival, and single kernel characteristics of the Global Durum Panel version 2 (GDPv2 n = 976), a panel …

Herbicide Management For Bromus Tectorum To Enhance Rangeland Productivity In Western Nebraska, Miranda Mueller

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

Cheatgrass, Bromus tectorum (L.), has increased in the mixed-grass prairies of the Nebraska Panhandle. Limited research is available in these ecosystems on the ecological factors that influences its spread and options for management. This study focuses on the efficacy of herbicide treatments (indaziflam and imazapic) as a cheatgrass control method on the native rangelands of western Nebraska. In September of 2022, a mixture of indaziflam (73 g ai ha^-1, Rejuvra) and imazapic (70 g ai ha^-1, Plateau) was aerially applied at 6 unique upland ecological sites (1-3 ha) near Scottsbluff, Nebraska. Functional group plant biomass data …

Genetic And Soil Influences On The Grapevine Rhizosphere Microbiome, Lauren M. Quackenbush

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

In vineyard cropping systems, the rhizosphere microbiome arises through recruitment and filtering of the bulk soil microbiome shaped over time by soil carbon and nitrogen, climate, pH and historical legacies of vineyard management. The recruitment and filtering steps occur under the genetic influences of rootstock and scion that together drive variability in rhizosphere microbiome diversity and composition.

This study compares rhizosphere microbiomes of four Pinot Noir blocks under two rootstocks (101-14 and 420A) and four scions (777, 828, Calera, Mt. Eden). Core microbiomes were consistent across all replicates. The most abundant bacterial phyla were Actinobacteriota, Proteobacteria, and Acidobacteriota …

Addressing Agricultural Mulch Challenges In Specialty Crop Production, Caleb David Wehrbein

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

Agricultural mulches are an essential yield-boosting tool in modern specialty crop production that provide weed suppression, temperature modulation, and moisture conservation functions. Polyethylene plastic mulches are the most widely used agricultural mulch but are not sustainable given their pollutive effect on the environment and challenges associated with recycling. In order to move towards a more sustainable industry, plastic mulch use in agriculture should become more efficient or replaced with more environmentally friendly alternatives. Biodegradable mulches may be a suitable alternative to plastic mulch, but they are often less durable and prematurely degrade in field conditions. Considering this, my dissertation research …

Applications Of Archaeal Antioxidant Coenzyme M As An Agricultural Biostimulant, Jeremy Hunter Brown

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

As the demand to meet global food security goals continue to increase, the need to increase efficiency and productivity of agricultural output also rises. This calls for innovative and cost-effective methods for improving plant growth and yield. Here we explore how antioxidants, molecules that inhibit oxidation and are necessary for redox based signaling and redox homeostasis, can be utilized as chemical biostimulants. Specifically, we investigated Coenzyme M, an antioxidant from archaea that holds potential economic advantages over other antioxidants. Chapter 1 provides a comprehensive review of antioxidants and how exogenously application of them affects plant growth and biology, highlighting the …

Too Much Of A Good Thing: Lessons From Compromised Rootworm Bt Maize In The Us Corn Belt, Ziwei Ye, Christina Difonzo, David A. Hennessy, Jinhua Zhao, Felicia Wu, Shawn P. Conley, Aaron J. Gassmann, Erin W. Hodgson, Bryan Jensen, Janet J. Knodel, Bradley Mcmanus, Lance J. Meinke, Andrew Michel, Bruce Potter, Nicholas J. Seiter, Jocelyn L. Smith, Joseph L. Spencer, Kelley J. Tilmon, Robert J. Wright, Christian H. Krupke

Department of Entomology: Faculty Publications

Widespread use of genetically engineered maize targeting the corn rootworm complex (Diabrotica species) has raised concerns about insect resistance. Twelve years of university field trial and farm survey data from ten United States Corn Belt states indicate that maize hybrids expressing toxins derived from the bacterium Bacillus thuringiensis (Bt maize) exhibited declining protection from rootworm feeding with increased planting while pest pressures simultaneously decreased. The analysis revealed a tendency to overplant Bt maize, leading to substantial economic losses; this was particularly striking in eastern Corn Belt states. Our findings highlight the need to go beyond the “tragedy of the …

Nebraska Crop Budgets Updated For 2025, Glennis Mcclure

Cornhusker Economics

For the 2025 production season, 83 crop budgets were developed for Nebraska. These budgets show slightly lower per-unit costs compared to 2023 and 2024. The primary factor behind the reduction in input costs is the lower estimated costs of fuel and fertilizer. In most cases, machinery depreciation and opportunity costs remained relatively stable, while land values and rental rates increased slightly. Additionally, seed and interest costs also rose in the 2025 budgets. Budget scenarios for individual producers may vary depending on the timing of their input purchases and fluctuations in prices.

The Nebraska crop budgets are updated annually to serve …

Nebraska Seed Focus, March 2025, Nebraska Crop Improvement Association

Nebraska Seed Focus

Nebraska Seed Focus, March 2025

Nebraska Seed Focus, June 2025, Nebraska Crop Improvement Association

Nebraska Seed Focus

Nebraska Seed Focus, June 2025

2025-2026 Seed Book, Nebrasa Crop Improvement Association

Nebraska Crop Improvement Association Seed Guides

2025-2026 seed book, Nebraska Crop Improvment Association.

Nebraska Seed Focus, September 2025, Nebraska Crop Improvement Association

Nebraska Seed Focus

Nebraska Seed Focus, September 2025

Introduction To Hydroponics- 2025-2026 Workshop Handbook, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

Hydroponically grown plants grow faster than traditional production systems, with greater productivity, greater palatability, and having optimal visual character. Three principal components of a system include the plant support platform, a nutrient solution reservoir, and an interface for the root-solution. This publication provides in-depth explanation to system design, evaluation of water quality, nutrient formulation, and prototype systems that can be easily constructed for those wanting to explore hydroponics, such as educators, organizational leaders, or home enthusiasts.

Geometric Modeling, Reconstruction And Evaluation Of Maize Leaf Morphology In 3d, Zhaocheng Xiang

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

Maize is a vital crop for global food security, yet quantitative characterization of its three-dimensional (3D) morphology remains a major challenge due to the geometric complexity of curved leaf structures and occlusions during data collection. This work presents an integrated framework for the digital reconstruction, parametric modeling, and functional analysis of maize leaf morphology and canopy architecture, advancing the precision and interpretability of phenotyping and modeling in smart agriculture.

First, we propose a descriptive and parametric model that represents maize leaves through three fundamental components: midrib, cross-section, and blade contour. Each is described by geometric curves and controlled by biologically …

Leaf-Based Varietal Categorization Of Sweetpotato (Ipomoea Batatas L. Lam.), A Potentially Healthful Vegetable, Using Image Processing And K-Means Clustering, Shahidul Islam, Md Towfiqur Rahman, Md Hamidul Rahman, Abdul Momin

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

Sweetpotato (Ipomoea batatas Lam) leaves contain higher concentrations of phenolic compounds, flavonoids, and carotenoids that are remarkable in health promotion. However, the nutrient content in sweetpotato leaves varies from variety to variety, and leaf shape and color are the key identifying factors for the varietal classification of sweetpotatoes. So, detecting sweetpotato leaves is essential for the in-situ identification of sweetpotato varieties and for developing intelligent agricultural systems. This study aimed to create a leaf-shape-based varietal classification technique for sweetpotato using image processing techniques coupled with a K-means clustering algorithm. 38 leaf images (RGB) of two sweetpotato cultivars were collected …

Greenhouse Management For The Smaller Structure--Educational And Hobby, Stacy A. Adams

Department of Agronomy and Horticulture: Faculty Publications

Greenhouses used for teaching or by hobbyist are smaller than those used for commercial production or found in the retail environment. Structural materials, covering, mechanical equipment, and control systems often are packaged as a kit made available through greenhouse suppliers. Supplier construction services may not be available, in which buyers must use local contractors to complete the installation. Greenhouses are unique structures that differ greatly from sheds or other outbuildings. They have coverings that allow maximum light transmittance, protected from UV degradation, and can handle wide inside to outside temperature extremes. This extension circular provides valuable information on the character, …

Addressing Food Security In Cameroon, Stacy A. Adams, Ruth Abunaw Besong

Department of Agronomy and Horticulture: Faculty Publications

Cameroon Africa has experience a period of nearly a decade of unrest as militants fight for independence for two Anglophone regions within a predominantly Francophone country. The English-speaking minority have felt aggrieved for continued erosion of rights by the central government. Protests have rapidly spread since 2016, causing closure of schools, businesses, and medical facilities. People have lost homes and been displaced, negatively affecting food production and crop availability. The United States Department of State leads an effort of diplomacy beyond emergency food relief through the Mandela Washington Fellowship that connects American professionals to innovative and impactful young African leaders. …