Earth Sciences Commons^™

Rice Biomass Response To Various Phosphorus Fertilizers In A Phosphorus-Deficient Soil Under Simulated Furrow-Irrigation, Jonathan B. Brye

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Wastewater-recovered phosphorus (P), in the form of the mineral struvite (MgNH4PO4⋅6H2O), may provide a sustainable alternative to rapidly decreasing rock phosphate reserves. Struvite can be generated via chemical and/or electrochemical precipitation methods, potentially reducing the amount of P runoff to aquatic ecosystems. The objective of this greenhouse tub study was to evaluate the effects of chemically- and electrochemically precipitated struvite (CPST and ECST, respectively) on above- and belowground plant response in a hybrid rice cultivar (Gemini 214, RiceTec) grown using furrow-irrigation compared to other common fertilizer-P sources [i.e., triple super phosphate (TSP) and diammonium phosphate (DAP)] in a P-deficient silt …

Isotopic Ecology Of Bison And Bootherium At Big Bone Lick, Kentucky, Frances Stephenson

Electronic Theses and Dissertations

Big Bone Lick (BBL) is a late Pleistocene and Holocene fossil locality in the Ohio River valley of Kentucky. This study utilized stable isotopes (δ¹³C, δ¹⁸O, and ⁸⁷Sr/⁸⁶Sr) in tooth enamel to reconstruct mobility and diet in Bison, as well as diet in Bootherium bombifrons. Isotopic results from seven Bison and two B. bombifrons are reported. Results suggest Pleistocene Bison and Bootherium occupied different dietary niches. Although both had C3-dominated diets, Bison occupied more open environments than B. bombifrons. Two bison from the late Holocene deposit had diets that consisted …

Tropical Atlantic Temperature And Hydrologic Shifts During The Paleocene-Eocene Thermal Maximum, Chels Howard

All Graduate Theses and Dissertations, Fall 2023 to Present

The Paleocene-Eocene Thermal Maximum (PETM) is a geologic climate event that is studied heavily due to the similarities to anthropogenic climate change. This event occurred approximately 56 million years ago (Ma) and is characterized by a rapid release of carbon into the atmosphere, which resulted in an increase in temperature and a change in global climate events such as changes in patterns of evaporation and precipitation. We see this effect occurring in modern anthropogenic climate change due to the burning of fossil fuels releasing carbon dioxide (CO₂) into the atmosphere. In this study I use elemental data of …

Constraining Silicate Weathering During The Middle Eocene Climatic Optimum (Meco) Using Radiolarian Ge/Si, Olivia R. Laub

All Graduate Theses and Dissertations, Fall 2023 to Present

Silicate weathering has long been considered a fundamental component of the earth system and has been cited as one of, if not the primary stabilizing feedback for climate. However, recent work has shown that the role of silicate weathering in the climate system is more complicated and dynamic than previously assumed. In this study I examine the role of weathering in the enigmatic warming event, the Middle Eocene Climatic Optimum (MECO) that occurred approximately 40 Ma. This event works as a good case study as there are multiple features of the MECO that differentiate it from other warming events that …

Multi-Objective Water Management In Idaho's Henrys Fork Watershed: Leveraging Reservoir Operation And Groundwater Pathways To Benefit Aquatic Habitat, Christina N. Morrisett

All Graduate Theses and Dissertations, Fall 2023 to Present

Multi-user water management is a challenging arena further complicated by climate change. This research is based in the Henrys Fork, Snake River, Idaho—an agricultural watershed that exemplifies those throughout the semi-arid American West. This dissertation uses an integrated approach that considers groundwater-river relationships, farm-scale decisions and basin-scale outcomes, upstream reservoir operation for downstream aquatic habitat, water rights, and collaborative stakeholder management to identify drought adaptation strategies accordingly.

Chapter 2 uses an interdisciplinary approach to quantify how improvements to irrigation efficiency at the farm-scale (i.e., converting from flood to sprinkler irrigation) can add up to affect hydrology at the landscape-scale and …

Controls On Sediment Connectivity In Fluvial Networks Impacted By Wildfire Across Utah, Alec Arditti

All Graduate Theses and Dissertations, Fall 2023 to Present

Flooding and sedimentation caused by wildfire are among the greatest threats to watersheds, fish populations and reservoirs in the western US. Burned landscapes are at risk for increased runoff and erosion and have the potential to transport sediment that may put downstream resources at risk. The ability of the channel to transport sediment downstream, known as the connectivity, is important for determining where impacts may occur. Sediment bottlenecks are locations within the watershed where local conditions produce a persistent decrease in downstream connectivity of sediment, resulting in increased sediment deposition and potentially a substantial modification of the local channel and …

Opening Speech, Ray Smith

IGC Proceedings (2001-2023)

No abstract provided.

Biodiversity—The Birds And The Bees And Healthy Grasslands, D. Borrenpohl, Pat D. Keyser

IGC Proceedings (2001-2023)

Losses in biodiversity abound in modern agroecosystems, and biodiversity loss hampers ecosystem function and primary productivity comparable to abiotic stress. One of the most endangered ecosystems in the world is North American tallgrass prairie, and native birds and pollinators that historically depended on tallgrass prairie are in precipitous decline. Fortunately, native warm-season grasses that dominated tallgrass prairie present a valuable opportunity for summer forage to beef producers in the Eastern United States—a time when coolseason grasses endure a lack in productivity called the “summer slump.” Tallgrass prairie was sustained by periodic disturbance from grazing and fire, and combining fire and …

The Soil Health Properties Of Native Grasslands, C. Bitler, Pat Keyser

IGC Proceedings (2001-2023)

Due to an increased interest in soil health and the role soils can have in carbon sequestration, native grasslands are getting heightened attention. Native grasslands are known for their deep top-soils that develop over time through the accumulation of soil organic matter. The deep and fibrous root systems that make up two-thirds of the biomass of native grasslands are the primary contributors to the soil organic carbon (SOC) content of grassland soils. Increased SOC content has a cascading effect on soil health metrics through increasing water infiltration and water holding capacity, supporting diverse and abundant soil microbial life, and improving …

Using Functional Ecology To Predict Restoration Success In Managed Grasslands, J. Bergman

IGC Proceedings (2001-2023)

Plants have developed remarkable functional variation over evolutionary time to cope with different environmental conditions. As a result, functional variation – measurable as functional traits above and below ground – can be found within but also among grassland communities today. The functional space covered by a community is thereby restricted by environmental factors while each single species within the community inhabits a specific niche with a certain breadth along different environmental gradients. Data from field sampling in European grasslands have shown, that species intraspecific functional variation can cover considerable amounts of possible functional spaces, hence holding the potential to establish …

Toxic Plants In Grasslands And Their Impact On Livestock, A. C. Barr

IGC Proceedings (2001-2023)

Grasslands are critical infrastructure for most cow/calf operations. Quality and abundance of pasture grasses directly influence livestock rate of gain, thereby affecting livestock margins and production costs, which determine the profitability of stocker operations. Successful cattlemen control weeds to preserve healthy pasture but also to prevent plant poisonings that may reduce individual animal performance or cause fatalities. Integrated Toxic Plant Management (ITPM) programs teach ranchers to identify the potentially toxic plants, recognize symptoms of plant poisonings, and use appropriate strategies to control those plants. Toxic plants can produce a range of effects in cattle and other grazing species. Nightshades ( …

Response Of Reproductive Phenology To Soil Water Content Of Stipa Breviflora Under Warming And Nitrogen Application, L. Bai, H. Y. Ren, G. D. Han

IGC Proceedings (2001-2023)

Plant phenology is considered as the most direct and sensitive characteristic indicators of plant response to regional climate change. Based on the observation data of phenology and soil water content of Stipa breviflora in an experimental platform of warming and nitrogen application in Inner Mongolia desert steppe from 2009 to 2019. The results showed that warming and nitrogen application significantly advanced the reproductive phenological period (P < 0.001), and the interaction of warming and nitrogen application promoted the advance of reproductive phenological period (P < 0.05).

Conference Agenda, Igc

IGC Proceedings (2001-2023)

No abstract provided.

Modelling Basal Area Of Perennial Grasses In Australian Semi-Arid Wooded Grasslands, S. G. Marsden, K. C. Hodgkinson

IGC Proceedings (2001-2023)

In many semi-arid pastoral systems, landscape processes easily become dysfunctional. Shifts to less functional states may be irreversible, and have long-term consequences for pastoral profitability and social viability of rural communities. Typically, shifts to lower functional states involve a decline in perennial grasses (Hodgkinson, 1994). Here we develop a conceptual basis for modelling the basal area of perennial grasses in a semi-arid grassland and validate the model using data from a 10-year grazing study.

The Effect Of Manipulated Conservation Margins In Intensively Grazed Dairy Paddocks On The Biodiversity Of Pteromalidae And Braconidae (Hymenoptera: Parasitica), A. Anderson, G. Purvis, A. Helden, H. Sheridan

IGC Proceedings (2001-2023)

Conserving field margins provides an opportunity to enhance biodiversity in agricultural landscapes. The parasitoid Hymenoptera represent one of the most diverse and biologically specialised of all insect groups and play an important role in insect pest control (LaSalle & Gauld, 1993). The diversity of parasitiods in any habitat is theoretically likely to reflect the diversity of host taxa. The aim of this study was to assess the effects of field margin manipulations on the diversity of parasitoids as a wider indication of effects on general arthropod diversity.

Plant Diversity Patterns Along Altitudinal Gradient In Understory Communities Of Darkesh Region, Bojnord, Iran, A. Arjmandi, H. Ejtehadi, F. Memariani, Mansour Mesdaghi

IGC Proceedings (2001-2023)

The ecotone region of Darkesh with an area of 22,500 hectares is located in the Irano-Turanian xeric-continental bioclimatic zone of Khorassan-Kopet Dagh. To investigate the plant diversity patterns of understory communities along three elevation classes of 1100-1600, 1600-2100, and 2100-2600 m, 187 plots were sampled randomly and abundance and cover of species were recorded using 4-m² plots. Beta diversity and Hill indices were calculated by using R and PAST software. A total of 252 species were recorded including 31 perennial grasses. The most abundant grasses were Poa nemoralis, Poa bulbosa, Bromus sterilis, Brachypodium sylvaticum, and Dactylis glomerata subsp. glomerata …

Using Genetic Diversity In Deep Root Systems Of Perennial Forage Grasses And Rice To Capture Carbon In Tropical Soils, J. Arango, Daniel M. Villegas, R. N. Jauregui, J. A. Cardoso, C. Costa Jr., C. Rebolledo, M. F. Alvarez, M. Selvaraj, L. Rodriguez, M. Mayorga, P. Chavarriaga, A. Notenbaert, M. Quintero, M. Da Silva, Manabu Ishitani, M. Peters, I. Rao, Joe Tohme

IGC Proceedings (2001-2023)

Agricultural soils have the potential not only to be sinks of carbon dioxide (CO₂) but also to mitigate the emissions of this gas to the atmosphere, thus, alleviating global warming. Perennial tropical grasses and rice upland and lowland varieties exhibit a large untapped genetic diversity in their root systems (e.g., deep rooting ability, exudation rates and chemical composition) that, if unlocked, could contribute to increased food production in crop-livestock systems while enhancing soil organic carbon (SOC) in tropical regions. Naturebased solutions that improve crop adaptation and SOC storage in tropical soils could help to remove CO₂ from …

Salt Tolerance Mechanisms In Perennial Fodder Grasses, Edna Antony, B. Aravind, A. Amulya, T. Anushree, P. V. Rakshata, F. H. Savitha, M. B. Doddamani, P. V. Kuligod, Akbar, Vinod Kumar, K. Sridhar, Vijay Kumar Yadav

IGC Proceedings (2001-2023)

Salinity stress is one of the most damaging stresses in crop plants. It reduces the productivity of the soil and makes it unsuitable for crop cultivation. Fodder crops are considered the best alternative in such uncultivable land. Using salinity-affected land for pasture development is the best alternative to utilize such lands. However, the extent of salinity tolerance varies among different grass species. In this study, Pearl millet Napier hybrids (PMN hybrid) and guinea grass varieties were studied for salinity tolerance in artificially created saline soils in the ratio of 13:7:1:2 (NaCl: Na₂SO₄: MgCl: CaSO₄, …

Effect Of Soil Nitrogen And Water Content On The Establishment Of A Lolium Perenne L. And Trifolium Repens L. Pasture, M. F. Alonso, Oscar A. Balocchi, I. Calvache, O. Martínez

IGC Proceedings (2001-2023)

Climate change has decreased rainfall in Southern Chile affecting the productivity of the grasslands that sustain the dairy and beef cattle industries. These grasslands are mainly mixtures of Lolium perenne L. and Trifolium repens L. Thus, we study the response on the establishment of a mixture of these two species to three levels of soil water content and two levels of nitrogen (N) fertilization. The trial was carried out in containers sowed in a complete randomized block´s design. Soil moisture measurements were taken daily. N fertilizations was applied at the establishment and every 60 days. Leaf appearance rate was measured …

Impact Of Level Of Use On Plant Vigor And Weight Of Festuca Humilior And Calamagrostis Vicunarum, T. Edson, L. Aguirre, E. R. Flores

IGC Proceedings (2001-2023)

Tussock grasslands of Festuca humilior and Calamagrostis vicunarum cover a significant extension of the central Andes of Peru, constituting a plant association highly appreciated by cattle ranchers. The objective of this research was to estimate the cumulative impact of the level of use of the key grasses Festuca humilior and Calamagrostis vicunarum on plant height, vigor, and weight. This study was conducted in a humid grassland of regular condition located at 4186 masl in the Puna ecoregion. The variables evaluated were: plant height, basal and canopy diameter and plant weight. The experiment lasted two years in which individual plants from …