Physical Sciences and Mathematics Commons^™

Will Saf Turbocharge The Corn Ethanol Market?, Richard Perrin, Lilyan Fulginiti, Felipe Miranda De Souza Almeida

Cornhusker Economics

The long-run outlook for the corn ethanol industry is questionable, due to a transition to electric and hybrid vehicles. One source of hope for the long run is the potential demand for producing Sustainable Aviation Fuel (SAF). SAF is a key component in the United States Aviation Climate Action Plan, a path to net-zero greenhouse gas (GHG) emissions in the aviation industry by 2050. Demand for ethanol for SAF offers hope to the ethanol industry, but it depends a great deal on policy decisions that are being made now. Here we sketch out this story.

Based on the information available …

Β-Sheets Mediate The Conformational Change And Allosteric Signal Transmission Between The Aslov2 Termini, Sian Xiao, Mayar Terek Ibrahim, Gennady M. Verkhivker, Brian D. Zoltowski, Peng Tao

Mathematics, Physics, and Computer Science Faculty Articles and Research

Avena sativa phototropin 1 light-oxygen-voltage 2 domain (AsLOV2) is a model protein of Per-Arnt-Sim (PAS) superfamily, characterized by conformational changes in response to external environmental stimuli. This conformational change begins with the unfolding of the N-terminal A'α helix in the dark state followed by the unfolding of the C-terminal Jα helix. The light state is characterized by the unfolded termini and the subsequent modifications in hydrogen bond patterns. In this photoreceptor, β-sheets are identified as crucial components for mediating allosteric signal transmission between the two termini. Through combined experimental and computational investigations, the Hβ …

Field Research Report: Results From The Enreec Vri Field For The 2021, 2022, And 2023 Crop Seasons, Derek M. Heeren, Ali T. Mohammed, Eric Wilkening, Christopher M. U. Neale, Alan L. Boldt, Ankit Chandra, Precious Nneka Amori, Ivo Z. Goncalves, Yeyin Shi, Guillermo R. Balboa

Department of Biological Systems Engineering: Conference Presentations and White Papers

Long-term irrigation management research has been conducted from 2014 to 2023 for corn and soybean at the Eastern Nebraska Research, Extension, and Education Center (ENREEC) Variable Rate Irrigation (VRI) Field located in subhumid east-central Nebraska (in the Lower Platte North Natural Resources District). The objective of this report was to present the overall results from the VRI Field for 2021 to 2023. Across the three growing seasons, there were the following irrigation treatments: Best Management Practice (BMP), 50% BMP, 125% BMP, rainfed, Spatial ET Modeling Interface (SETMI), SDD1, SDD2, machine-learning-based Cyber-Physical System (CPS), a student team recommended rate, and industry …

Toward A Coordinated Understanding Of Hydro-Biogeochemical Root Functions In Tropical Forests For Application In Vegetation Models, Daniela F. Cusack, Bradley Christoffersen, Chris M. Smith-Martin, Kelly M. Andersen, Amanda L. Cordeiro, Katrin Fleischer, S. Joseph Wright, Nathaly R. Guerrero-Ramírez, Laynara F. Lugli, Lindsay A. Mcculloch, Mareli Sanchez-Julia, Sarah A. Batterman, Caroline Dallstream, Claire Fortunel, Laura Toro, Lucia Fuchslueger, Michelle Y. Wong, Daniela Yaffar, Joshua B. Fisher, Marie Arnaud, Lee H. Dietterich, Shalom D. Addo-Danso, Oscar J. Valverde-Barrantes, Monique Weemstra, Jing Cheng Ng, Richard J. Norby

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Tropical forest root characteristics and resource acquisition strategies are underrepresented in vegetation and global models, hampering the prediction of forest–climate feedbacks for these carbon-rich ecosystems. Lowland tropical forests often have globally unique combinations of high taxonomic and functional biodiversity, rainfall seasonality, and strongly weathered infertile soils, giving rise to distinct patterns in root traits and functions compared with higher latitude ecosystems. We provide a roadmap for integrating recent advances in our understanding of tropical forest belowground function into vegetation models, focusing on water and nutrient acquisition. We offer comparisons of recent advances in empirical and model understanding of root characteristics …

Perennializing Marginal Croplands: Going Back To The Future To Mitigate Climate Change With Resilient Biobased Feedstocks, Salvador Ramirez Ii, Marty R. Schmer, Virginia L. Jin, Robert B. Mitchell, Catherine E. Stewart, Jay Parsons, Daren D. Redfearn, John J. Quinn, Gary E. Varvel, Kenneth P. Vogel, Ronald F. Follett

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

Managing annual row crops on marginally productive croplands can be environmentally unsustainable and result in variable economic returns. Incorporating perennial bioenergy feedstocks into marginally productive cropland can engender ecosystem services and enhance climate resiliency while also diversifying farm incomes. We use one of the oldest bioenergy-specific field experiments in North America to evaluate economically and environmentally sustainable management practices for growing perennial grasses on marginal cropland. This long-term field trial called 9804 was established in 1998 in eastern Nebraska and compared the productivity and sustainability of corn (Zea mays L.)—both corn grain and corn stover—and switchgrass (Panicum virgatum …

Using Phenology To Unravel Differential Soil Water Use And Productivity In A Semiarid Savanna, Blake Steiner, Russell L. Scott, Jia Hu, Natasha Mcbean, Andrew Richardson, David J. P. Moore

University Administration Publications

Savannas are water-limited ecosystems characterized by two dominant plant types: trees and an understory primarily made up grass. Different phenology and root structures of these plant types complicate how savanna primary productivity responds to changes in water availability. We tested the hypothesis that productivity in savannas is controlled by the temporal and vertical distribution of soil water content (SWC) and differences in growing season length of understory and tree plant functional types. To quantify the relationship between tree, understory, and savanna-wide phenology and productivity, we used PhenoCam and satellite observations surrounding an eddy covariance tower at a semiarid savanna site …

Can Phytoremediation-Induced Changes In The Microbiome Improve Saline/Sodic Soil And Plant Health?, Achal Neupane, Duncan Jukubowski, Douglas Fiedler, Liping Gu, Sharon A. Clay, David E. Clay, Shin-Yi Marzano

Agronomy, Horticulture and Plant Science Faculty Publications

Increasing soil salinity and/or sodicity is an expanding problem in the Northern Great Plains (NGP) of North America. This study investigated the impact of phytoremediation on the soil microbiome and if changes, in turn, had positive or negative effects on plant establishment. Amplicon sequencing and gas chromatograph/mass spectrometer analysis compared root metabolites and microbial composition of bulk vs. rhizosphere soils between two soil types (productive and saline/sodic). Beta-diversity analysis indicated that bacterial and fungal communities from both the bulk and rhizosphere soils from each soil type clustered separately, indicating dissimilar microbial composition. Plant species also influenced both root-associated bacterial and …

Assessing The Morphological And Physiological Traits Of Smooth Brome Pastures Under Long Term Grazing And Nutrient Enrichment In Eastern Nebraska, Hassan Shehab

School of Natural Resources: Dissertations, Theses, and Student Research

Climate change together with the increase in demands for food, feed, fuel, and fiber are becoming a threat to sustainability and resilience of agriculture and pasture lands. Bromus inermis (smooth bromegrass) dominates pastures for cattle grazing in Eastern Nebraska, US, where it is planted in monocultures, and is considered high quality forage because of its palatability and high nutritional value for cattle, especially under intensive management practices. Sustainable management of these pastures is key to long-term resilience. This study aims to assess the performance of smooth bromegrass pastures to the combined effects of long-term management practices (since 2005) of fertilization …

Human Dimensions Of Woody Encroachment Management In Nebraska, Emily Rowen

School of Natural Resources: Dissertations, Theses, and Student Research

Woody plant encroachment (WPE) is a social-ecological problem that will challenge conservation professionals and agricultural producers to adapt their management strategies. This research first examined WPE from the perspective of individual conservation professionals through an online survey. Conservation professionals’ attitudes about adaptation to vegetation transitions, such as WPE, were of interest because these attitudes are one measure of how prepared this group is to respond to WPE. Hypothesized predictors of adaptation attitude were tested through linear regression modeling. These predictors included ecological change, observation of WPE, or risk perception. It was found that risk perception was the strongest predictor of …

Game-Theoretic Approaches To Optimal Resource Allocation And Defense Strategies In Herbaceous Plants, Molly R. Creagar

Department of Mathematics: Dissertations, Theses, and Student Research

Empirical evidence suggests that the attractiveness of a plant to herbivores can be affected by the investment in defense by neighboring plants, as well as investment in defense by the focal plant. Thus, allocation to defense may not only be influenced by the frequency and intensity of herbivory but also by defense strategies employed by other plants in the environment. We incorporate a neighborhood defense effect by applying spatial evolutionary game theory to optimal resource allocation in plants where cooperators are plants investing in defense and defectors are plants that do not. We use a stochastic dynamic programming model, along …

Volcanic Diffuse Volatile Emissions Tracked By Plant Responses Detectable From Space, Robert R. Bogue, Peter M. J. Douglas, Joshua B. Fisher, John Stix

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Volcanic volatile emissions provide information about volcanic unrest but are difficult to detect with satellites. Volcanic degassing affects plants by elevating local CO2 and H2O concentrations, which may increase photosynthesis. Satellites can detect plant health, or a reaction to photosynthesis, through a Normalized Difference Vegetation Index (NDVI). This can act as a potential proxy for detecting changes in volcanic volatile emissions from space. We tested this method by analyzing 185 Landsat 5 and 8 images of the Tern Lake thermal area (TLTA) in northeast Yellowstone caldera from 1984 to 2022. We compared the NDVI values of the thermal area with …

Are Plant–Soil Feedbacks Caused By Many Weak Microbial Interactions?, Julia K. Aaronson, Andrew Kulmatiski, Leslie E. Forero, Josephine Grenzer, Jeanette M. Norton

Wildland Resources Student Research

We used high-throughput sequencing and multivariate analyses to describe soil microbial community composition in two four-year field plant–soil feedback (PSF) experiments in Minnesota, USA and Jena, Germany. In descending order of variation explained, microbial community composition differed between the two study sites, among years, between bulk and rhizosphere soils, and among rhizosphere soils cultivated by different plant species. To try to identify soil organisms or communities that may cause PSF, we correlated plant growth responses with the microbial community composition associated with different plants. We found that plant biomass was correlated with values on two multivariate axes. These multivariate axes …

Belowground Growth Strategies Of Native And Invasive Rhizomatous Perennial Grasses In Response To Precipitation Variability, Clipping, And Competition, Surendra Bam, Jacqueline P. Ott, Jack Butler, Lan Xu

Natural Resource Management Faculty Publications

Invasive clonal species may exhibit different growth strategies than their native clonal competitors. In this study, we examined the spatial distribution of tiller outgrowth and the bud bank by comparing the investment in phalanx versus guerilla growth of a native and invasive perennial grass in North America. We also examined the efect of altered precipitation frequency, clipping, and competition on their clonal growth strategies. Investment in phalanx and guerilla growth was assessed by examining live propagule and tiller production from the plant crown versus its rhizomes. Although invasive Bromus inermis and native Pascopyrum smithii exhibited similar clonal growth strategies as …

Variation Of Carbon Stock Of Boca Del Drago Mangrove Forests Based On Salinity And Seaward Proximity, Fiona Wyrtzen

Independent Study Project (ISP) Collection

Mangrove forests, at the intersection of land and sea, are considered one of the most important marine environments for their variety of ecosystem services and their ability to sequester large amounts of carbon in their biomass and adjacent soils. With a changing climate, many of the abiotic and biotic factors influencing mangroves will begin to shift, potentially impacting resilience, growth capacity, and distribution of mangroves worldwide. This study aimed to examine the influence of changing salinity on the carbon stock capacity for Rhizophora mangle and Laguncularia racemosa forests, and the distribution of biomass in each species relative to salinity in …

Soil Succession: Short And Long-Term Impacts Of Grazing On Soil Properties In A Tropical Montane Cloud Forest, June Curtis

Independent Study Project (ISP) Collection

Cattle ranching is the leading cause of deforestation in South America, causing long-lasting alterations to the continent's landscape and ecology. Tropical montane cloud forests (TMCFs) are a rare ecosystem particularly vulnerable to the effects of land conversion to pasture, a process which has implications ranging from biodiversity loss to soil degradation. Grazing is known to significantly alter soils' physical structure through processes of compaction and erosion as well as significant additions of organic matter. Silvopasture, or the integration of pasture and forest, has emerged as an alternative to traditional grazing practices with the hope of mitigating environmental and soil degradation. …

The Truth Behind Avocado Expansion In The Algarve: A Synthesis Of Public, Environmental Associations, And Government Perspectives And Response, Mandy Ausman

Independent Study Project (ISP) Collection

Avocado expansion has exponentially increased in the Algarve region of southern Portugal in recent years. The surge in expansion has provoked contention and discrepancy in the media regarding how and if avocado production can persist in the water-scarce region due to worsening drought conditions related to climate change coupled with the fruit’s significant water footprint. This paper aims to synthesize the arguments and response of the public, environmental associations, and government agencies to the expansion of avocado production in the water- scarce region of the Algarve, highlight the region’s current challenges of avocado expansion and water management regulation, and analyze …

Portugal To New Mexico: Investigating The Applicability Of Syntropic Agriculture To A Semi-Arid Continental Climate, Arielle Nathan

Independent Study Project (ISP) Collection

Conventional industrial agriculture has numerous detrimental effects on the environment including high carbon emissions, pollution and overconsumption of water, soil degradation, and reduction of biodiversity (FAO, 2018). Large-scale alternatives are needed to combat these negative consequences and provide climate solutions. Syntropic Agriculture is a promising farming alternative especially in arid systems subject to degraded soils and desertification. New Mexico is a semi-arid continental climate in a prolonged period of drought and predicted to experience worsening agricultural conditions due to desertification, wildfire intensification, and exacerbated water scarcity. In an area with similar agricultural challenges, a project in Mértola, Portugal (Terra Sintrópica) …

Community Complexity Of A Pollination Network: Analysis Of Plant-Pollinator Interactions In The Eastern Ecuadorian Cloud Forest, Anisa López-Ruiz

Independent Study Project (ISP) Collection

Global declines in pollinators and temporal/spatial mismatches between plants and pollinators threaten the integrity of plant-pollinator networks. Ecological network analysis provides a powerful framework for understanding the dynamics of plant-pollinator networks and measures of community complexity that can help inform areas of priority in conservation. This study observed a plant-pollinator network in a secondary forest close to the Río Zuñac Reserve in the eastern Ecuadorian cloud forest to identify assemblages of plants and pollinators and evaluate measures of community complexity, including specialization and nestedness. Flowering plants were identified and observed along a 1.2 km transect, and floral visitors to these …

Friends In High Places: Establishing Pollination Networks For The Páramos Of Central Ecuador, Emma Diaz

Independent Study Project (ISP) Collection

Well-known for being a global biodiversity hotspot, the Andean Páramos hosts a unique array of floristic diversity seen nowhere else in the world (Luteyn, n.d.). With the resiliency of this ecosystem dependent on the successful reproduction of these plants, it is crucial to understand the pollination network which sustains them. Modern-day research has outlined networks in the Chilean, Venezuelan, and Argentinean Páramos, but one has yet to be defined for Ecuador, despite being the suspected home to nearly half of floristic diversity in the Páramos (Arroyo et al., 1985; Pelayo et al., 2021; Medan et al., 2023; Caranqui et al., …

Assessing The Performance Of Agricultural Systems In The Inland And Coastal Regions Of Northern Portugal Using Indicators: Establishing The Foundation Towards Better Agricultural Practices, Genevieve Gehlken

Independent Study Project (ISP) Collection

This study conducts a comprehensive evaluation of agricultural systems in the distinct coastal and inland regions of Northern Portugal. Employing key indicators, including soil erosion, nitrogen surplus, irrigation practices, Agricultural Gross Domestic Product (GDP), and crop yield, the analysis reveals statistically significant disparities and unique challenges in each region. The coastal areas, marked by higher agricultural GDP, exhibit distinct economic dependencies on agriculture, while the inland regions face challenges related to water scarcity, soil erosion, and rural isolation. The looming threat of climate change adds complexity to these dynamics, further highlighting the need for region-specific, sustainable agricultural practices. In the …

Mineral Licks As A Potential Nidus For Parasite Transmission, William J. Severud, Todd M. Kautz, Jerrold L. Belant, Seth A. Moore

Natural Resource Management Faculty Publications

Discrete landscape features can concentrate animals in time and space, leading to non-random interspecific encounters. These encounters have implications for predator-prey interactions, habitat selection, intraspecific competition, and transmission of parasites and other pathogens. The lifecycle of the parasitic nematode Parelaphostrongylus tenuis requires an intermediate host of a terrestrial gastropod. Natural hosts of P. tenuis are whitetailed deer, and an aberrant host of conservation concern is moose, which are susceptible to high levels of mortality as a naive host to the parasite. Intermediate hosts become infected when P. tenuis larvae are shed in deer feces, then consumed or enter the gastropod …

Evaluation Of Native Plant Communities On Nebraska Game And Parks Commission State Parks, Robert F. Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report evaluates the Native Plant Communities on Nebraska Game and Parks Commission State Parks East Region, also known as Region 3, which includes much of northeast and extreme eastern Nebraska, including portions of the lower Niobrara, Elkhorn and Platte Rivers and nearly the entire east border formed by the Missouri River. Fifteen state-listed threatened and endangered species have been recorded within the boundaries of Region 3 within the last twenty years. Several of these occupy habitats within major river channels.

Surveyed areas which contained habitat for legally protected species include Dead Timber State Recreation Area, Indian Cave State Park, …

Managing Water Quality To Enable Future Irrigation Development In The Kimberley Region, Department Of Primary Industries And Regional Development, Western Australia

Natural resources commissioned reports

Three-Dimensional Hydrodynamic Modelling to Evaluate the Effect of Farm Chemicals on the Lower Pools of the Keep River

The National Water Grid Authority awarded the Department of Primary Industries and Regional Development (DPIRD) a project entitled ‘Managing Water Quality to Enable Future Irrigation Development in the Kimberley Region’.

The purpose of the project is to review the current and future risk profile of agrichemicals (pesticides) in the Keep River catchment (Ord - East Kimberley) in the context of irrigation development across the last decade and proposed in the medium term. The results of the review were to define prospective mitigation …

Updating The Dual C And O Isotope—Gas-Exchange Model: A Concept To Understand Plant Responses To The Environment And Its Implications For Tree Rings, Rolf T. W. Siegwolf, Marco M. Lehmann, Gregory R. Goldsmith, Olga V. Churakova (Sidorova), Cathleen Mirande-Ney, Galina Timoveeva, Rosmarie B. Weigt, Matthias Saurer

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The combined study of carbon (C) and oxygen (O) isotopes in plant organic matter has emerged as a powerful tool for understanding plant functional responses to environmental change. The approach relies on established relationships between leaf gas exchange and isotopic fractionation to derive a series of model scenarios that can be used to infer changes in photosynthetic assimilation and stomatal conductance driven by changes in environmental parameters (CO₂, water availability, air humidity, temperature, nutrients). We review the mechanistic basis for a conceptual model, in light of recently published research, and discuss where isotopic observations do not match our …

Review Of Toxicity Of Agricultural Chemicals And Implications For Aquatic Fauna Of The Keep River, Samanatha Reynolds, David Morgan

Natural resources commissioned reports

This report was compiled for the Western Australian Department of Primary Industries and Regional Development (DPIRD) as part of the National Water Grid Authority (NWGA) project entitled “Managing water quality to enable future irrigation development in the Kimberley Region, WA”. The purpose of this report is to review the toxicity of farm chemicals (herbicides and insecticides) used by farm operators in the Keep River catchment and their potential impacts on the aquatic species in the river, in particular those species that are listed under the Environment Protection and Biodiversity Conservation Act 1999. It is designed to complement the report entitled …

Report On And Recommendations Arising From The Visit Of Dr Michael Warne (University Of Queensland) And Robert Sluggett To Kununurra, Michael Warne Dr, Rob Sluggett

Natural resources commissioned reports

Dr Michael Warne of the Reef Catchments Science Partnership and Robert Sluggett of Farmacist Pty Ltd were invited by Richard George of Department of Primary Industries and Regional Development (DPIRD) to visit Kununurra, Western Australia.

The project was financially supported by the National Water Grid Authority project “Managing water quality to enable future irrigation development in the Kimberley Region”. The aim of the visit was for Dr Warne and Rob Sluggett to engage with farmers, key stakeholders and staff from DPIRD in order to understand the agriculture and water quality in the Ord and Keep river region; and to share …

Detection Of A Diverse Endophyte Assemblage Within Fungal Communities Associated With The Arundo Leaf Miner, Lasioptera Donacis (Diptera: Cecidomyiidae), Marie-Claude Bon, John A. Goolsby, Guy Mercadier, Fatiha Guermache, Javid Kashef, Massimo Cristofaro, Ann T. Vacek, Alan Kirk

School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

The larvae of Lasioptera donacis Coutin feed on fungal communities lining galleries within the mesophyll of leaf sheaths of Arundo donax in an aggregative manner. It has been stated that L. donacis could have established a fundamental symbiotic relationship with one fungus, although the fungal composition of these communities remains unsettled. Using a culture-dependent approach and ITS sequencing, the present work characterizes and compares the fungal communities associated with L. donacis in Eurasia with the endophytes of A. donax in Texas where L. donacis is absent. The 65 cultivable isolates obtained from L. donacis fungal communities were sorted into 15 …

Deficit Irrigation Management For Irrigated Corn In Nebraska: Economically Viable?, Lia Nogueira, Cory Walters, Emily O'Donnell, Wesley Peterson, Suat Irmak

Cornhusker Economics

In this study we determine the economic value of deficit irrigation management using both technological and methodological advancements. The use of soil moisture probes represents the technological improvement. We provide improvements in the methodology as follows. Regarding data, we employ a field-size study, instead of plots, where the irrigation decision is determined by the moisture level in the soil measured through a soil moisture probe. Regarding the understanding of the yield response to water, although we examine the commonly used quadratic function, we improve upon this specification by also examining an alternative response function, the linear response stochastic plateau. Our …

Physiological And Transcriptomic Responses Of Two Artemisia Californica Populations To Drought: Implications For Restoring Drought-Resilient Native Communities, Hagop S. Atamian Dr., Jennifer L. Funk

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

As climate change brings drier and more variable rainfall patterns to many arid and semi-arid regions, land managers must re-assemble appropriate plant communities for these conditions. Transcriptome sequencing can elucidate the molecular mechanisms underlying plant responses to changing environmental conditions, potentially enhancing our ability to screen suitable genotypes and species for restoration. We examined physiological and morphological traits and transcriptome sequences of coastal and inland populations of California sagebrush (Artemisia californica), a critical shrub used to restore coastal sage scrub vegetation communities, grown under low and high rainfall environments. The populations are located approximately 36 km apart but …

Variation In The Growth Parameters And Biomass Of Rhizophora Mangle Seedlings With Distances From Playa Estrella, Bocas Del Toro, Panama, Thiny Tep

Independent Study Project (ISP) Collection

Mangrove is a salt-tolerant, intertidal, tropical tree or shrub and make up a rich community of various organism. On the Caribbean coast of Panama, in Bocas del Toro, mangrove forests cover 28 km² and are dominated by R. mangle, followed by L. racemosa and A. germinans. Simultaneously, Isla Colón, the most populated and developed among all islands in the Bocas del Toro Archipelago, is a tourist center. Unfortunately, tourism comes at the price of environmental degradation via alteration of natural habitats, solid and wastewater pollution. Therefore, this study aims to gain a preliminary understanding on how the …