Life Sciences Commons^™

The Effects Of Silver Nanoparticles On Soybean (Glycine Max) Growth And Nodulation, Paul J. Boersma

Electronic Thesis and Dissertation Repository

Due to their antimicrobial properties, silver nanoparticles (AgNPs) have become more popular in consumer and industrial products, leading to increasing agricultural and environmental concentrations. Exposure to AgNPs could be detrimental to plants, microbes, and their symbiotic relationships. When subjected to 10 µg/mL AgNPs in a 96-well plate, growth of Bradyrhizobium japonicum USDA 110 was halted. In hydroponic culture with 2.5 µg/mL AgNPs, biomass of inoculated Glycine max (L.) Merr. was 50% of control. Axenic plants were unaffected by this dose, but growth was inhibited at higher doses, indicating that AgNPs inhibit both nodulation and growth. Nodules treated with 2.5 µg/mL …

Assessing Selective Plasmids For Bradyrhizobium Sp. Doa9 And Mesorhizobium Loti, Aiden J. Wilcox, Rebecca Meaney, Bogumil Karas

Undergraduate Student Research Internships Conference

No abstract provided.

Climate-Driven Impacts Of Warming And Grazing On Sub-Arctic Coastal Wetlands In Alaska, Ryan T. Choi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is rapidly warming the Arctic, especially at lower latitudes. Warmer temperatures and earlier springs are altering the timing of plants and animals, especially for long-distance migratory herbivores. Changes in the timing of both plants and herbivores have the potential to impact plant productivity and nutrient cycling, while also altering plant community diversity and composition.

In chapter 2, I conducted a field experiment to investigate how earlier growing seasons and differences in arrival times of migratory geese influence physical traits of sedge forage species. I found that both an earlier growing season and late grazing by geese had similar …

Testing Functional Variation In Thermal Properties For Antarctic Mosses, Andrew Forrest Clements

Dissertations and Theses

As the maritime Antarctic ecosystem continues to warm, glacial retreat will further expose subterranean permafrost to warmer conditions. One of the most visible changes in the ecosystem is the colonization of the new ice-free areas by bryophytes, particularly mosses. These bryophytes are having important effects on terrestrial thermal properties, but little is known about differences among Antarctic moss species in their thermal properties. Here, I measured the thermal conductivity, specific heat capacity, and the water content of moss species on King George Island to understand the insulation ability of Antarctic mosses, Polytrichastrum alpinum, Sanionia georgicouncinata, Chorisodontium aciphyllum, …

Dissolved Nitrogen Cycling In The Eastern Canadian Arctic Archipelago From Stable Isotopic Data, Holly Westbrook

Theses and Dissertations

Climate change is expected to drastically alter the input of inorganic nitrogen (N) sources in the Eastern Canadian Arctic Archipelago (ECAA) with increasing discharge from glacial meltwater and permafrost thawing. Since dissolved inorganic N is generally depleted in surface waters, dissolved organic N (DON) could represent a significant source of nutrients limiting primary production in Arctic ecosystems. Yet, few DON data for this region exist. We analyzed stable isotopes (δ¹⁵N and δ ¹⁸O of DON and NO₃-) to investigate dissolved nitrogen cycling in glacial rivers and marine surface samples collected in the ECAA during summer …

Soil Health Beneath Amended Switchgrass: Effects Of Biochar And Nitrogen On Active Carbon And Wet Aggregate Stability, Priya Saini, Jason P. De Koff, Richard Link, Chris Robbins

Agricultural and Environmental Sciences Faculty Research

Perennial crops, like switchgrass (Panicum virgatum L.), are important for bioenergy production and long-term carbon sequestration. Biochar, a byproduct of certain bioenergy production processes, is also identified as a potential tool for carbon sequestration and soil quality improvements, especially in marginal soils. Despite the focus on switchgrass, soil health characteristics under switchgrass production for biomass are unclear. This study focused on identifying the effects of four N rates (0, 17, 34, and 67 kg N ha−1) and biochar application (0 and 9 Mg ha−1) in a 3-year switchgrass field study on a silt loam soil. Soil active carbon (AC) and …

Protein And Carbohydrate Fractions In Sorghum Silage With Addition Of Urea And Two Storage Periods, F. E. P. Fernandes, R. Garcia, A. J. V. Pires, O. G. Pereira, D. R. Souza, F. B. L. Mendes, A. A. Pinheiro, C. S. Fernandes

IGC Proceedings (1997-2023)

No abstract provided.

Effect Of Combined Fertilization On Seed Production Of Xinnong‐1 Bermudagrass, Yanhui Zhang, Abulaiti, Peiying Li

IGC Proceedings (1997-2023)

No abstract provided.

Effect Of Nitrogen And Foliar Spray Of Bio‐Regulators On Seed Production Of Lasiurus Sindicus, Nagendra Singh Yadava

IGC Proceedings (1997-2023)

No abstract provided.

Elevated Atmospheric Co2 Concentration Triggers Redistribution Of Nitrogen To Promote Tillering In Rice, Juan Zhou, Yingbo Gao, Junpeng Wang, Chang Liu, Zi Wang, Minjia Lv, Xiaoxiang Zhang, Yong Zhou, Guichun Dong, Yulong Wang, Jianye Huang, Dafeng Hui, Zefeng Yang, Youli Yao

Biology Faculty Research

Elevated atmospheric CO₂ concentration (eCO₂) often reduces nitrogen (N) content in rice plants and stimulates tillering. However, there is a general consensus that reduced N would constrain rice tillering. To resolve this contradiction, we investigated N distribution and transcriptomic changes in different rice plant organs after subjecting them to eCO₂ and different N application rates. Our results showed that eCO₂ significantly promoted rice tillers (by 0.6, 1.1, 1.7, and 2.1 tillers/plant at 0, 75, 150, and 225 kg N ha⁻¹ N application rates, respectively) and more tillers were produced under higher N application rates, …

Molecular Detection Of Pathogenic Leptospira And Microbial Source Tracking Of Fecal Pollution In San Juan, Puerto Rico, Taylor I. Chapman

Biology Theses

Leptospirosis, caused by pathogenic Leptospira, is endemic to tropical regions. Leptospira is released into the environment through the secretion of urine from animals, making it easily transmissible through water sources. The estuarian environment surrounding the area of San Juan, Puerto Rico and its high density of urban development creates ideal conditions for transmission of Leptospirosis. The goal of this study was to determine the presence of Leptospira in these surface waters and use Microbial Source Tracking (MST) to identify the possible source of pathogenic Leptospira. Eighty-seven water samples were collected during the dry (44) and wet (43) seasons. …

The Fate And Cycling Of Nitrogen, Phosphorous, And Trace Heavy Metals In Beaver-Altered Headwater Streams, Desneiges S. Murray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Human land-use can increase the amount of non-point source (NPS) pollution in a stream, negatively affecting ecosystem health and beneficial services provided by an ecosystem. Unfortunately, NPS pollution remains high in many waterbodies. Beaver dams may be a passive, cost-effective strategy for removing NPS pollution in headwater streams because beaver dams slow stream flow and collect sediments. Impounded sediments can change how nutrients and pollutants are cycled in a stream through multiple pathways. In the first part of our study, we investigated whether beaver activity can reduce nitrogen, phosphorous and heavy metals from otherwise traveling downstream. Results suggest beaver ponds …

Investigations Of Substrate Reduction By Nitrogenase: Light Powered Substrate Reduction By A Cds:Femoco System And Understanding Dinitrogen Inhibition Of Electron Transfer, Hayden Kallas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation is a key step of the nitrogen cycle which makes biologically inert N₂ gas available for organisms to use in the form of ammonia. Nitrogen fixing microorganisms all contain the same enzyme called nitrogenase which catalyzes the six electron transfers to N₂ required for conversion into ammonia. Nitrogenase is a two-component enzyme that contains a cofactor composed of iron and sulfur as well as heavier metals whose identity can be molybdenum, vanadium, or an additional iron atom depending on the variant. The two components of nitrogenase are the MFe protein and the Fe protein. The Fe …

Evaluation Of Irrigation And Nutrient Management Strategies In Rice Using Alternative Irrigation Methods, Justin Lee Chlapecka

Graduate Theses and Dissertations

As water resources gain value across the Mid-South, alternative irrigation strategies of rice (Oryza sativa L.) have garnered increasing attention. In 2015, an estimated 1.7% of Arkansas rice hectarage used alternate wetting and drying (AWD) irrigation and 0.9% used furrow irrigation. As of 2020, 2.5% used AWD and 16.9% used furrow irrigation, the latter accounting for near 99,000 ha in Arkansas. Little information exists in the scientific literature in relation to management of rice grown in the Mid-South without a conventional flood. This fact coupled with the rapid adoption rate, especially for furrow-irrigated rice (FIR), during the last five years …

Quantifying The Leaching Of Nutrients And Metals In A Pasture Soil As Affected By Excreta Of Ruminants Fed Alternative Diets, Ian Kennedy

Graduate Theses and Dissertations

The leaching of nitrate through the soil profile and into adjacent water systems has been a leading cause of water pollution and results in the loss of a valuable nutrient from animal production systems. Forage-based animal production systems may be improved through manipulation of animal diets that incorporate tannins and total polyphenolic compounds with feed, increasing the amount of nitrogen (N) retained by an animal/decreasing rates of digestion and altering the N-containing compounds that are excreted and deposited onto soil. Incorporating the forage legumes sericea lespedeza (Lespedeza cuneate [Dumont de Courset] G. Don) and lablab (Lablab purpurues L.) into the …

Nitrogen Use Efficiency And Soil Bioavailable Nitrogen In Corn Silage Production In A Semi-Arid Environment, Phearen Miller

Student Research Symposium

As agriculture intensifies, the world faces a dual challenge of increasing food production while reducing impacts of excess reactive nitrogen (N) in the environment. A field study examining different N sources in corn silage under semi-arid conditions was conducted at the Greenville farm in northern Utah (41°45’ N, 1111°48’52 W) since 2012. The experimental design is a randomized complete block design with four blocks and four treatments: control (no nitrogen), low ammonium sulfate (AS 112 kg N/ha), high ammonium sulfate (AS 224 kg N/ha), and steer manure compost (224 kg total N/ha). We examined yield, nitrogen use efficiency (NUE), and …

Estimating The Denitrification Rate In Hood Canal Using Water Circulation, Spencer Johnson

WWU Honors College Senior Projects

Hood Canal is a long, fjordal estuarine inlet. Because of a sill near its mouth, Hood Canal experiences regular low oxygen in its bottom water; recently, dissolved oxygen has been even lower than usual, leading to fish kills and other ecosystem damage. Anthropogenic nutrients, particularly nitrogen, may be the cause, so it is important to quantify the components of the nitrogen cycle, like denitrification. To my knowledge, there is only one estimate of denitrification from Hood Canal in the literature. This study sought to supplement that data with an independent estimate of denitrification using water circulation along with N2 concentrations …

Ecosystem-Scale Biogeochemical Fluxes From Three Bioenergy Crop Candidates: How Energy Sorghum Compares To Maize And Miscanthus, Caitlin E. Moore, Adam C. Von Haden, Mark B. Burnham, Ilsa B. Kantola, Christy D. Gibson, Bethany J. Blakely, Evan C. Dracup, Michael D. Masters, Wendy H. Yang, Evan H. Delucia, Carl J. Bernacchi

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

Perennial crops have been the focus of bioenergy research and development for their sustainability benefits associated with high soil carbon (C) and reduced nitrogen (N) requirements. However, perennial crops mature over several years and their sustainability benefits can be negated through land reversion. A photoperiod-sensitive energy sorghum (Sorghum bicolor) may provide an annual crop alternative more ecologically sustainable than maize (Zea mays) that can more easily integrate into crop rotations than perennials, such as miscanthus (Miscanthus × giganteus). This study presents an ecosystem-scale comparison of C, N, water and energy fluxes from energy sorghum, maize and miscanthus during a typical …

Nitrogen Status In Leaves Of Poapratensis In Relation To Nitrogen Fertilization Strategy In Intensive Lawn Utilization, Piotr Goliński, Barbara Golińska

IGC Proceedings (1997-2023)

No abstract provided.

Nitrogen Release From Turfgrass Clippings With Different Fertilization Rates, Karin Kauer, Tiina Köster, H. Raave, R. Viiralt, A. Selge

IGC Proceedings (1997-2023)

No abstract provided.

Corn Grain Weight: Dependence Upon Nitrogen Supply And Source-Sink Relations, J. A. Fernandez, I. A. Ciampitti

Kansas Agricultural Experiment Station Research Reports

From a yield component perspective, final grain yield in corn (Zea maysL.) is the result of the number of grains per unit area and their final grain weight. The understanding of grain weight parameters, the rate and duration of grain growth, is critical to improve our rational design of management practices and breeding strategies. In this study, we attempted to determine the effect on grain weight and grain-filling parameters of source-sink modifications (i.e. the amount of assimilates available per grain) during linear grain fill under contrasting levels of nitrogen (N) fertilization in two commercially available US corn hybrids. …

Corn Yield Response To Sulfur Applied With Nitrogen Fertilizer, T. E. Husa, D. A. Ruiz Diaz

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to evaluate the effect of nitrogen (N) with added sulfur (S) fertilizer on corn yield. The treatments included 1) a control with no sulfur and no nitrogen; 2) urea ammonium nitrate (UAN) (180 lb N/a; 0 lb S/a); and 3) UAN plus ammonium thiosulfate (ATS) (180 lb N/a; 15 lb S/a). Both the UAN and UAN+ATS were balanced to 180 lb N/a. These three treatments were evaluated at two locations in 2019 and three locations in 2020. Preliminary results show that yield trended upward with the application of nitrogen plus sulfur fertilization over N …

Timing, Source, And Placement Of Nitrogen Fertilizer Increases Wheat Yield And Protein Content In High Yielding Environments, L. M. Simão, D. A. Ruiz Diaz, R. P. Lollato

Kansas Agricultural Experiment Station Research Reports

The efficiency of nitrogen (N) fertilizer management depends on rate, timing, placement, and source, but the benefits of an integrated program have not been clearly quantified, to our knowledge. This study aimed to investigate the effects of integrated N management on winter wheat grain yield, grain protein content, grain test weight, and biomass in Kansas. The study consisted of two N management treatments: Normal (single N application as UAN using broadcast nozzles with the absence of urea inhibitors); and Progressive (split N application into two timings using streamer bars with urease inhibitors). Both treatments had similar results in all variables …

Do Different Wheat Varieties Respond Differently To Nitrogen Rates In Terms Of Grain Yield And Grain Protein Concentration In Kansas?, N. Giordano, R. P. Lollato

Kansas Agricultural Experiment Station Research Reports

Nitrogen management in wheat can result in positive impacts on grain yield and grain protein concentration (GPC) if addressed correctly. The aim of this study was to compare whether different varieties responded differently in terms of grain yield and GPC to management of nitrogen (N) rate across different environments. Factorial field experiments were carried out in a split-plot design in four different Kansas locations to evaluate the combination of four N rates (whole plot, 0, 40, 80, and 120 lb N/a) and fourteen different commercially available winter wheat varieties (sub-plots). Grain yield and GPC were measured at harvest maturity. The …

Wheat Variety Yield Response To Nitrogen And Sulfur Rates During The 2019–2020 Growing Season, B. R. Jaenisch, T. Wilson, N. Nelson, M. Guttieri, R. P. Lollato

Kansas Agricultural Experiment Station Research Reports

Early spring visual sulfur (S) deficiency symptoms are increasingly a concern for Kansas wheat growers, but the extent of yield limitation due to S deficiencies and its interaction with nitrogen (N) supply is not well quantified in this environment. Our objective was to evaluate the responses of three wheat varieties to the interaction of N and S rates. The experiment was conducted in four Kansas locations during the 2019–2020 winter wheat growing season: Ashland Bottoms, Argonia, Belleville, and Hutchinson. These locations were selected to provide a range in soil textures and organic matter content, as these variables might impact the …

Long Term Nutrient And Chlorophyll A Dynamics Across Long Island Sound And Impacts On Dissolved Oxygen Conditions Within The Western Sound (1991-2019), Sherry Perreira

Dissertations and Theses

Nitrogen overload, eutrophication, and hypoxia have been challenging and persistent water quality problems in Long Island Sound (LIS) over the past decades with major impacts on commercial industries, ecology, and recreational activities in the region. Recognizing these problems, the EPA enforced three phases of the Clean Water Act (CWA) to reduce nitrogen loads in an effort to improve this important estuary. This study examines how nitrogen (NH₃, NO_x & TDN), chlorophyll a (CHLA), and dissolved oxygen (DO) concentrations changed in LIS over the past 30 years, in response to water quality regulations as well as changes in …

Evaluation Of Corn Agronomic Management Practices Following A Rye Cover Crop, Daniel John Quinn

Theses and Dissertations--Plant and Soil Sciences

Fall implementation of a rye (Secale cereale L.) cover crop (RCC) prior to spring corn (Zea mays L.) planting is a management practice used to improve soil conservation, water quality, and limit herbicide dependence. However, corn growth and yield following a RCC is often reduced due to early-season nitrogen (N) stress and decreased plant emergence, which can limit RCC adoption. The objective(s) of this research were to evaluate corn agronomic management practices (e.g., N and seeding rate management, in-furrow (IF) starter use) following a RCC and determine which management practices can be used to limit corn stress following …

Effects Of Nitrogen And Phosphorus Input On Lake Louise, Dallas, Luzerne County, Pa, Hailey Kubiski, Cosima Wiese

Student Research Poster Presentations 2021

The runoff of nitrogen and phosphorus can be detrimental to a lakes health and ability to support life (Baker, et al. 2007). Eutrophication is a product of large amounts of nitrogen and phosphorous in lakes (Rice and Horgan, 2017). The purpose of this study is to examine if large amounts of nitrogen and phosphorus are present in Lake Louise. The proposed research question is: Are there high concentrations of nitrogen and phosphorus in and around Lake Louise? The null hypothesis of this study is that there will be no significant difference in nitrogen and phosphorus concentrations in areas in and …

Date Of Planting And Nitrogen Management For Malt Barley Production In The Northeast Usa, Arthur Siller, Masoud Hashemi, Alexandra Smychkovich, Caroline Wise, Heather Darby

Data and Datasets

There is an increasing market for locally grown malting barley (Hordeum vulgare L.) in the Northeast US. Malting barley must meet certain quality standards for acceptability in the brewing market. Up-to-date recommendations are needed regionally for adaptation to ongoing climate change. A two-year field experiment was conducted to assess the interactive influence of three dates of planting (5 Sept., 15 Sept, and 25 Sept.), two levels of fall N (0 or 28 kg ha^-1), and three levels of spring N (28, 50.5, and 73 kg ha^-1). No significant difference was detected in grain yield amongst …

Nitrogen Fertilizer Timing And Phosphorus And Potassium Fertilization Rates For Established Endophyte-Free Tall Fescue: Year 3, D. W. Sweeney, J. K. Farney, J. L. Moyer, D. A. Ruiz Diaz

Kansas Agricultural Experiment Station Research Reports

Tall fescue production was measured during the third production year of a study with locations started in fall of 2016 and fall of 2017. Phosphorus (P) fertilization rate af­fected spring harvest yield at Site 1, but not at Site 2. Applying nitrogen (N) in late fall or late winter resulted in greater spring yields than applying N in spring or not applying N. However, fall harvest yields at Site 1 were greater with spring N application, but not at Site 2. The third-year tall fescue total yield rank as affected by N fertilizer timing was late winter>late fall=spring>no …