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The Implications Of Climate Change For Nebraska: Summary Report Of Sector-Based Roundtable Discussions, Donald A. Wilhite, Kimberly Morrow

National Drought Mitigation Center: Faculty Publications

This report is the result of the work of many individuals that contributed to the success of the series of eight sector-based roundtable events that were held in September and October of 2015. First and foremost, we would like to thank the organizers and the organizations they represent for their leadership in bringing together a diverse set of key stakeholders to discuss the implications of climate change on their sector. It was such a pleasure to work with such a dedicated group of individuals. Second, we would like to thank the more than 350 people who participated in these discussions …

Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter

Theses and Dissertations--Plant and Soil Sciences

Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …

Using Satellite Vegetation And Compound Topographic Indices To Maphighly Erodible Cropland Buffers For Cellulosic Biofuel Cropdevelopments In Eastern Nebraska, Usa, Yingxin Gu, Bruce K. Wylie

United States Geological Survey: Staff Publications

Cultivating annual row crops in high topographic relief waterway buffers has negative environmental effects and can be environmentally unsustainable. Growing perennial grasses such as switchgrass(Panicum virgatum L.) for biomass (e.g., cellulosic biofuel feedstocks) instead of annual row crops in these high relief waterway buffers can improve local environmental conditions (e.g., reduce soil erosion and improve water quality through lower use of fertilizers and pesticides) and ecosystem services (e.g.,minimize drought and flood impacts on production; improve wildlife habitat, plant vigor, and nitro-gen retention due to post-senescence harvest for cellulosic biofuels; and serve as carbon sinks). The main objectives of this …

Amino Acid Specific Stable Nitrogen Isotope Values In Avian Tissues: Insights From Captive American Kestrels And Wild Herring Gulls, C.E. Hebert, B.N. Popp, K.J. Fernie, C. Ka’Apu-Lyons, B.A. Rattner, N. Wallsgrove

United States Geological Survey: Staff Publications

Through laboratory and field studies, the utility of amino acid compound-specific nitrogen isotope analysis (AA-CSIA) in avian studies is investigated. Captive American kestrels (Falco sparverius) were fed an isotopically characterized diet and patterns in δ15N values of amino acids (AAs) were compared to those in their tissues (muscle and red blood cells) and food. Based upon nitrogen isotope discrimination between diet and kestrel tissues, AAs could mostly be categorized as source AAs (retaining baseline δ15N values) and trophic AAs (showing 15N enrichment). Trophic discrimination factors based upon the source (phenylalanine, Phe) and trophic (glutamic acid, Glu) AAs were 4.1 (muscle) …

Amino Acid Specific Stable Nitrogen Isotope Values In Avian Tissues: Insights From Captive American Kestrels And Wild Herring Gulls, C.E. Hebert, B.N. Popp, K.J. Fernie, C. Ka’Apu-Lyons, B.A. Rattner, N. Wallsgrove

United States Geological Survey: Staff Publications

Through laboratory and field studies, the utility of amino acid compound-specific nitrogen isotope analysis (AA-CSIA) in avian studies is investigated. Captive American kestrels (Falco sparverius) were fed an isotopically characterized diet and patterns in δ15N values of amino acids (AAs) were compared to those in their tissues (muscle and red blood cells) and food. Based upon nitrogen isotope discrimination between diet and kestrel tissues, AAs could mostly be categorized as source AAs (retaining baseline δ15N values) and trophic AAs (showing 15N enrichment). Trophic discrimination factors based upon the source (phenylalanine, Phe) and trophic (glutamic acid, Glu) AAs were 4.1 (muscle) …

Phosphorus Release Potential Of Agricultural Soils Of The United States, Rebecca A. Young

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

Phosphorus (P) is one of the leading causes of surface water quality decline in the United States, leading to algal blooms and hypoxia in lakes and streams. Decreasing conservation funds dictate that agencies such as the Natural Resources Conservation Service, maximizes its effectiveness and efficiency in implementing practices to address P management and runoff on agricultural lands. Additional information on P behavior in soil is needed to improve P management plans to reduce pollution risk at the watershed, farm, and field scales. This research focuses on the development of total soil P release models, to be included into assessment and …

Mitigating N2o Emissions From Soil: From Patching Leaks To Transformative Action, C. Decock, Juhwan Lee, M. Necpalova, Engil Isadora Pujol Pereira, D. M. Tendall, Johan Six

School of Earth, Environmental, & Marine Sciences Faculty Publications

Further progress in understanding and mitigating N2O emissions from soil lies within transdisciplinary research that reaches across spatial scales and takes an ambitious look into the future.

Mycorrhizal Roots In A Temperate Forest Take Up Organic Nitrogen From 13c- And 15n-Labeled Organic Matter, Matthew A. Vadeboncoeur, Andrew P. Ouimette, Erik A. Hobbie

All Materials

Background and Aims

The importance of the uptake of nitrogen in organic form by plants and mycorrhizal fungi has been demonstrated in various ecosystems including temperate forests. However, in previous experiments, isotopically labeled amino acids were often added to soils in concentrations that may be higher than those normally available to roots and mycorrhizal hyphae in situ, and these high concentrations could contribute to exaggerated uptake.

Methods

We used an experimental approach in which we added ¹³C-labeled and ¹⁵N-labeled whole cells to root-ingrowth cores, allowing proteolytic enzymes to release labeled organic nitrogen at a natural rate, as …

Understanding The Impact Of Intensive Horticulture Land-Use Practices On Surface Water Quality In Central Kenya, Faith K. Muriithi, Danlin Yu

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Rapid expansion of commercial horticulture production and related activities contribute to declining surface water quality. The study sought to understand the impacts on select rivers in Laikipia and Meru, production hotspots. The specific aims were (1) to identify prevailing surface water quality by examining variations of 14 physico-chemical parameters, and (2) to categorize measured surface water quality parameters into land use types highlighting potential pollutant source processes. Water samples were collected in July and August 2013 along 14 rivers in the study area. The data were analyzed using principal component analysis (PCA) and discriminant analysis (DA). Principal components (PCs) explained …

The Effect Of Warming And Simulated Rainfall On Soil Microbial Community Structure And Function, Torri A. Ivancic

Biology Theses

Soil respiration, from plant roots and soil microbes, accounts for 60 – 80 percent of total ecosystem respiration, with the microbial component contributing approximately 54 percent. Global climate trends resulting from CO₂ emissions include increased soil temperatures and changes in precipitation regimes resulting in less frequent, more intense rainfall events. Soil temperature and moisture availability drive soil respiration rates, but how they impact the microbial respiration is poorly qualified. I investigated how the soil microbial community responds to changes in temperature and moisture availability in a laboratory based experiment. Soils from a mixed hardwood forest under two thermal regimes …

Defining The Potassium Nutritional Requirements And Distribution Among Plant Parts Of Representative Soybean Cultivars From Different Maturity Groups, Md. Rasel Parvej

Graduate Theses and Dissertations

The potassium (K) requirement of soybean [Glycine max (L.) Merr.] was investigated to determine whether cultivar sensitivity to K deficiency was affected by growth habit (determinate or indeterminate) and how cultivars from each growth habit accumulate and distribute K among plant structures. We also diagnosed K deficiency across reproductive growth stages (R2-6) using trifoliolate leaf- and petiole-K concentrations and at harvest (R8) using seed-K concentration. Soybean responded similarly to K deficiency in terms of yield, selected yield components, and seed-K concentration, regardless of growth habit. The yield loss from K deficiency was greatest on the middle to upper nodes of …

Validation Of Soil-Test-Based Phosphorus And Potassium Fertilizer Recommendations For Rice And Soybean, Matthew Scott Fryer

Graduate Theses and Dissertations

The science of soil-testing for nutrient management and fertilizer recommendations is widely accepted among scientists and agronomists. Although this science is unsurpassed in predicting soil nutrient availability, soil-test interpretations are seldom validated. Major research objectives for irrigated soybean [Glycine max (L.) Merr.] and direct-seeded, delayed-flood rice (Oryza sativa L.) were to: i) validate the accuracy of Mehlich-3 soil-test P (STP) and K (STK) interpretations and ii) published critical tissue-P and -K interpretations in predicting the yield response to fertilizer at different significance levels (p≤0.05 to 0.25), iii) examine how seed nutrient concentrations are influenced by fertilization and crop response to …

Decomposition And Nitrogen Dynamics Of Turtle Grass (Thalassia Testudinum) In A Subtropical Estuarine System, Monica Delgado

Theses and Dissertations

Seagrass beds are pivotal in the functioning of coastal ecosystems in terms of productivity, organic matter turnover and nutrient cycling. Aiming to document decay and nitrogen (N) dynamics of turtle grass (Thalassia testudinum) in a subtropical estuarine system, decomposition patterns of leaves and rhizomes were characterized and compared. Nitrogen usage during decomposition of tissues, and of live tissues and epiphytes growing on live leaves, was also quantified and compared. Stable isotope ratios allowed tracing N within the seagrass bed, following N incorporation into seagrass tissues from the surrounding media (water, sediment). Leaves had a higher N content and decomposed at …

A Comparative Analysis Of Portable X-Ray Fluorescence Spectrometry And Stable Isotopes In Assessing Ancient Coastal Peruvian Diets, Theresa Jane Gilbertson

USF Tampa Graduate Theses and Dissertations

This dissertation explores a cross-cultural analysis of the dietary signatures of four coastal cultures of prehistoric Peru. A combination of elemental analysis based on portable x-ray fluorescence spectrometry (pXRF), testing trace elements presented in 209 individuals’ skulls representing the Nazca (38), Cañete (33), Lima (40), and Moche (98) valleys and/or cultures of the first millennium AD, is weighed in conjunction with isotope ratio mass spectrometry (IRMS) to analyze human bone collagen and bone apatite derived from a portion of the individuals represented in the Nazca, Cañete, and Lima cranial samples.

Evidence from the results of both tests are weighed using …

In Situ Studies Of Limestone Dissolution In A Coastal Submarine Spring, Rachel Marie Schweers

USF Tampa Graduate Theses and Dissertations

Limestone dissolution in karst environments is likely due to geochemistry of the water, the actions of microbial communities, and the effect of water flow. We explored the rate of limestone dissolution and will examine here the microbial communities associated with the limestone. A conduit within the brackish cave, Double Keyhole Spring, on the coast of central west Florida was the site of the experiment. PVC pipes (5cm x 16cm) were filled with crushed limestone that was screened to a 1.9cm – 2.54cm size range. There were three treatments (5 replicates each): Control - sealed autoclaved controls with limestone and conduit …

The Founding Of The Robert B. Daugherty Water For Food Institute At The University Of Nebraska

Daugherty Water for Food Global Institute: Administrative Materials

University of Nebraska President J.B. Milliken drove to Omaha in to meet Robert Daugherty at his home. In the living room, the elder Daugherty was surrounded by Mogens Bay, his three sons and a covey of lawyers. Now 88 years old, the businessman had a reputation for being tough-minded and smart, a man who could intimidate, but also surprise with his ready sense of humor. In his long career, Daugherty had transformed agriculture and the rural landscape into the now familiar polka dot pattern, the signature of the center pivot irrigators Daugherty had popularized in the 1970s. He had started …

Pengaruh Dosis Pupuk Fosfor Dan Pupuk Organik Cair Terhadap Pertumbuhan Dan Hasil Kacang Hijau (Vigna Radiata L.) Pada Ultisol Jatinangor, Agus Wahyudin, Tati Nurmala, R. D. Rahmawati

Jurnal Kultivasi

Percobaan ini bertujuan untuk mengetahui pengaruh dosis pupuk fosfor dan pupuk organik cair terhadap pertumbuhan dan hasil tanaman kacang hijau (Vigna radiata L.). Percobaan dilaksanakan di kebun percobaan Fakultas Pertanian Universitas Padjadjaran, Jatinangor, Jawa Barat. Rancangan percobaan yang digunakan dalam penelitian ini adalah Rancangan Acak Kelompok (RAK) dengan sembilan perlakuan dan diulang tiga kali yaitu 50 kg ha-1 pupuk fosfor + O L ha-1 pupuk organik cair, 50 kg ha-1 pupuk fosfor + 4 L ha-1 pupuk organik cair, 50 kg ha-1 pupuk fosfor + 8 L ha-1 pupuk organik cair, 75 kg ha-1 pupuk fosfor + O L ha-1 …

A Multilevel Analysis Of Neighborhood Socioeconomic Effect On Preterm Births In Georgia, Usa, Wei Tu, Jun Tu, Stuart H. Tedders

Earth, Environment & Sustainability: Faculty Publications

This study estimates the neighborhood socioeconomic status (SES) effect on the risk of preterm birth (PTB) using multilevel regression (MLR) models. Birth data retrieved from year 2000 and 2010 Georgia Vital Records were linked to their respective census tracts. Principle component analysis (PCA) was performed on nine selected census variables and the first two principal components (Fac1 and Fac2) were used to represent the neighborhood-level SES in the MLR models. Two-level random intercept MLR models were specified using 122,744 and 112,578 live and singleton births at the individual level and 1613 and 1952 census tracts at the neighborhood level, for …

Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff

Ecosystem and Conservation Sciences Faculty Publications

Anthropogenic activities have significantly altered atmospheric chemistry and changed the global mobility of key macro-nutrients. Here we show that contemporary global patterns in nitrogen (N) and phosphorus (P) emissions drive large hemispheric variation in precipitation chemistry. These global patterns of nutrient emission and deposition (N:P) are in turn closely reflected in the water chemistry of naturally oligotrophic lake (r² = 0.81, p < 0.0001). Observed increases in anthropogenic N deposition play a role in nutrient concentrations (r² = 0.02, p < 0.05); however, atmospheric deposition of P appears to be major contributor to this pattern (r² = 0.65, p < 0.0001). Atmospheric simulations indicate a global increase in P deposition by 1.4 times the pre-industrial rate largely due to increased dust and biomass burning emissions. Although changes in the mass flux of global P deposition are smaller than for N, the impacts on primary productivity may be greater because, on average, one unit of increased P deposition has 16 times the influence of one unit of N deposition. These stoichiometric considerations, combined with the evidence presented here, suggest that increases in P deposition may be a major driver of alpine Lake trophic status, particularly in the Southern Hemisphere. These results underscore the need for the broader scientific community to consider the impact of atmospheric phosphorus deposition on the water quality of naturally oligotrophic lakes.

Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff

Watershed Sciences Faculty Publications

Anthropogenic activities have significantly altered atmospheric chemistry and changed the global mobility of key macronutrients. Here we show that contemporary global patterns in nitrogen (N) and phosphorus (P) emissions drive large hemispheric variation in precipitation chemistry. These global patterns of nutrient emission and deposition (N:P) are in turn closely reflected in the water chemistry of naturally oligotrophic lakes (r2 = 0.81, p < 0.0001). Observed increases in anthropogenic N deposition play a role in nutrient concentrations (r2 = 0.20, p < 0.05); however, atmospheric deposition of P appears to be major contributor to this pattern (r2 = 0.65, p < 0.0001). Atmospheric simulations indicate a global increase in P deposition by 1.4 times the preindustrial rate largely due to increased dust and biomass burning emissions. Although changes in the mass flux of global P deposition are smaller than for N, the impacts on primary productivity may be greater because, on average, one unit of increased P deposition has 16 times the influence of one unit of N deposition. These stoichiometric considerations, combined with the evidence presented here, suggest that increases in P deposition may be a major driver of alpine Lake trophic status, particularly in the Southern Hemisphere. These results underscore the need for the broader scientific community to consider the impact of atmospheric phosphorus deposition on the water quality of naturally oligotrophic lakes.

Ecology And Morphology Of The Late Miocene Musk Deer, Longirostromeryx Wellsi (Artiodactyla: Moschidae: Blastomerycinae), Katheryn Y. C. Chen

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Longirostromeryx wellsi, one of the latest surviving members of the extinct clade Blastomerycinae (Artiodactyla: Moschidae), possesses highly derived craniodental morphology that deviates from typical musk deer form. Previous work suggests that the unique anatomy of L. wellsi represents adaptations for occupying open savannas. To test this hypothesis I conduct principal components analysis on five postcranial bones of L. wellsi, comparing them to that of several extant ruminant artiodactyls, which are divided among seven habitat categories. These elements are also compared with the postcrania of other blastomerycines. These analyses indicate that L. wellsi anatomy is most similar to that of other …

Assessment Of Heavy Metal Concentration In Water Around The Proposed Mkuju River Uranium Project In Tanzania, Firmi P. Banzi, Peter K. Msaki, Najat K. Mohammed

Tanzania Journal of Science

Effective verification for compliance with water quality standards in uranium mining in Tanzania requires data sensitive to monitor heavy metal concentration in water around the Mkuju River Uranium Project before mining commences. The area susceptible for pollution by the project was estimated using AERMOD dispersion model and found to cover about 1300 km2. Thirty one surface and groundwater samples were collected and analysed for heavy metals and physicochemical properties using ICP-MS and standards techniques, respectively. The physicochemical properties for water samples analysed ranges from 5.7 to 7.8 for pH, 2.8 to 80.2 mg/L for TDS and 15 to 534.5 mS/cm …

Lithologic Controls On Bedrock Channel Morphology In The Buffalo River Basin, Evan A. Thaler

Graduate Theses and Dissertations

The longevity of high relief terrains in passive margin systems remains an explained phenomenon in geomorphology. Current landscape evolution models assume an equilibrium state between rock uplift rates and erosion rates. However, analysis of chi gradients of bedrock channels across several lithologies in the Buffalo River Basin reveals disequilibrium in the basin controlled by the presence of a thick interval of Pennsylvanian sandstone that caps many of the plateaus in the basin. Headwater channels beneath the caprock tend to have higher chi gradient values in all lithologies than headwater channels in basins where the sandstone caprock is absent. High chi …

Soil Quality In Relation To Forest Conversion To Perennial Or Annual Cropping In Southern Brazil, Elcio Liborio Balota, Ines Fumiko Ubukata Yada, Higo Furlan Amaral, Andre Shigueyoshi Nakatani, Mariangela Hungria, Richard Peter Dick, Mark S. Coyne

Plant and Soil Sciences Faculty Publications

Many forested areas have been converted to intensive agricultural use to satisfy food, fiber, and forage production for a growing world population. There is great interest in evaluating forest conversion to cultivated land because this conversion adversely affects several soil properties. We examined soil microbial, physical, and chemical properties in an Oxisol (Latossolo Vermelho distrófico) of southern Brazil 24 years after forest conversion to a perennial crop with coffee or annual grain crops (maize and soybeans) in conventional tillage or no-tillage. One goal was to determine which soil quality parameters seemed most sensitive to change. A second goal …

Iron-Mediated Stabilization Of Soil Carbon Amplifies The Benefits Of Ecological Restoration In Degraded Lands, Lucas C. R. Silva, Timothy A. Doane, Rodrigo S. Correa, Vinicius Valverde, Engil Isadora Pujol Pereira, William R. Horwath

School of Earth, Environmental, & Marine Sciences Faculty Publications

Recent observations across a 14‐year restoration chronosequence have shown an unexpected accumulation of soil organic carbon in strip‐mined areas of central Brazil. This was attributed to the rapid plant colonization that followed the incorporation of biosolids into exposed regoliths, but the specific mechanisms involved in the stabilization of carbon inputs from the vegetation remained unclear. Using isotopic and elemental analyses, we tested the hypothesis that plant‐derived carbon accumulation was triggered by the formation of iron‐coordinated complexes, stabilized into physically protected (occluded) soil fractions. Confirming this hypothesis, we identified a fast formation of microaggregates shortly after the application of iron‐rich biosolids, …

Insomniac Of The Soil: A Collection Of Poetry And Essays, Sarah E. Golibart

Senior Honors Projects, 2010-2019

“Insomniac of the Soil” is a homage to a landscape that has deeply informed Sarah Golibart's life and her artistic voice – the tidewater flatlands of Virginia’s Chesapeake Bay peninsula where her family lives and where Golibart has worked on farms since high school. Both her poems and essays are earthy, imagistic, and grounded – quite literally – in the soil as well as in a sensibility of ecological ethics and sustainability. “Insomniac of the Soil” is also a love song to the fervent and fallow cycles of the soil.

Water Balance Of Flooded Rice In The Tropics, Siva Sivapalan

Books & book chapters

Department of Agriculture and Food, WA staff member authored "Water Balance of Flooded Rice in the Tropics" in the publication Irrigation and Drainage - Sustainable Strategies and Systems’, edited by Muhammad Salik Javaid, published by INTECH, May 2015

Chapter Summary: Excess groundwater recharge rates under irrigated agriculture may lead to problems such as rising watertable, waterlogging and salinity. In irrigated areas, growers may need to manage this water and hence, understanding what leakage is attributed to what crops will become more important. In this study, evaporation, transpiration, and deep percolation losses were estimated for ponded rice culture, using a …

Assessing And Mapping Vulnerability And Risk Perceptions To Groundwater Arsenic Contamination : Towards Developing Sustainable Arsenic Mitigation Models, Sushant Kumar Singh

Theses, Dissertations and Culminating Projects

This study focuses on the arsenic-affected rural communities in Bihar located within the mid-Gangetic Plain in India. A random stratified sampling method is applied to survey 340 households in three villages (Suarmarwa, Rampur Diara, and Bhawani Tola), through a structured questionnaire. A reliable arsenic field testing kit is used to analyze the drinking water sources in the field, followed by a confirmatory test of a subset of water samples through Atomic Absorption Spectrophotometry. The study has two major goals: 1) Develop sustainable arsenic-mitigation models; and 2) Create a “composite vulnerability index,” and present the information as a map for use …

Rice Grain Yield And Nitrogen Uptake And Ammonia Volatilization From Urea As Affected By Urea Amendment And Simulated Rainfall, Randy Dempsey

Graduate Theses and Dissertations

The effect of rainfall between urea application and flood establishment on N loss and grain yield of rice (Oryza sativa L.) has not been studied. The first research objective was to compare the effects of simulated rainfall amounts and N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor rate on NH3 volatilization and rice growth. Three field experiments were conducted and NH3 volatilization was measured in two experiments for 11 days after urea application (DAU) in semi-open chambers. Urea or NBPT-treated urea (NBPT-Urea) was subjected to six simulated rainfall amounts (0-25 mm) applied 5 to 15 h after urea application and flooded 7 …

The Promise And Peril Of Intensive-Site-Based Ecological Research: Insights From The Hubbard Brook Ecosystem Study, Timothy J. Fahey, Pamela H. Templer, Bruce T. Anderson, John J. Battles, John L. Campbell, Charles T. Driscoll, Anthony R. Fusco, Mark B. Green, Karim-Aly S. Karrim, Nicholas L. Rodenhouse, Lindsay E. Rustad, Paul G. Schaberg, Matthew A. Vadeboncoeur

All Materials

Abstract.

Ecological research is increasingly concentrated at particular locations or sites. This trend reflects a variety of advantages of intensive, site-based research, but also raises important questions about the nature of such spatially delimited research: how well does site based research represent broader areas, and does it constrain scientific discovery?We provide an overview of these issues with a particular focus on one prominent intensive research site: the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. Among the key features of intensive sites are: long-term, archived data sets that provide a context for new discoveries and the elucidation of ecological mechanisms; …