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10,777 full-text articles. Page 8 of 208.

Long-Term Land Management Practices And Their Effect On Soil Health And Crop Productivity, Thomas Joseph Muratore Jr. 2019 University of Kentucky

Long-Term Land Management Practices And Their Effect On Soil Health And Crop Productivity, Thomas Joseph Muratore Jr.

Theses and Dissertations--Plant and Soil Sciences

Agricultural intensification reliant on monocrops could change soil health in a way that does not support maximum crop productivity. Twenty-nine-year-old no-till field plots at the University of Kentucky Spindletop research farm showed a significant reduction in corn yields from continuous corn plots compared to those from plots in various types of rotation. The objective of this study was to determine what role soil microbes might play in yield reduction and how management and time effects microbial community structure. Samples were collected from the following treatments: continuous corn (CC), continuous soybean (SS), a 2-year corn/soybean rotation (CCSS), Corn in rotation ...


Field Evaluation Of Tobacco Engineered For High Leaf-Oil Accumulation, James Perry 2019 University of Kentucky

Field Evaluation Of Tobacco Engineered For High Leaf-Oil Accumulation, James Perry

Theses and Dissertations--Plant and Soil Sciences

The biofuel market is dominated by ethanol and biodiesel derived from cellulosic and lipid-based biomass crops. This is largely due to the relatively low costs and reliability of production. At present, production of non-food plant-derived oils for biofuel production in the U.S. is minimal. A research team from the Commonwealth Scientific and Industrial Research Organization (CSIRO), an independent Australian federal government research institution, has developed an efficient transgenic system to engineer oil production in tobacco leaves. This novel system is comprised of multiple transgenes that direct the endogenous metabolic flux of oil precursors towards triacylglycerol (TAG) production. Additional genes ...


A Statistical Analysis Of Zea Mays Grain Yield Response To Nitrification-Inhibitor Amendments Under Field Conditions Utilizing Parametric And Non-Parametric Techniques, Elliot H. Sully 2019 Iowa State University

A Statistical Analysis Of Zea Mays Grain Yield Response To Nitrification-Inhibitor Amendments Under Field Conditions Utilizing Parametric And Non-Parametric Techniques, Elliot H. Sully

Graduate Theses and Dissertations

Nitrification is a matter of economic and ecological importance in nitrogen-tensive agricultural practices such as corn (Zea mays) grain production. When ammonium is bacterially oxidized into nitrate it becomes more susceptible to leaching and denitrification as nitrous oxide. The nitrification process not only adds to water and air pollution but also impacts on farm productivity by reducing grains yields and increasing fertilizer demands. Nitrification inhibiting fertilizer amendments can potentially improve grain yields by retarding the growth of nitrifying soil bacteria. Multiple field studies conducted across various locations and timespans have generated mixed results regarding the grain yield difference attributed to ...


The Effect Of Year-To-Year Variability On Planting Date And Relative Maturity Selection For Maize, Mitch Baum 2019 Iowa State University

The Effect Of Year-To-Year Variability On Planting Date And Relative Maturity Selection For Maize, Mitch Baum

Graduate Theses and Dissertations

Current maize (Zea mays L.) planting date recommendations have not been updated in the state of Iowa since 2001. A state that produced 68.8 million tons of maize on 5.5 million hectares in 2016. It is imperative that this information be regularly updated as both climate and maize hybrid selection are constantly changing. We analyzed maize yield and phenology, from a multi-location, year, relative maturity (RM), and planting date (PD) experiment carried out in Iowa, US. The dataset was used to calibrate a site-specific model (Agricultural Production System sIMulation, APSIM) and extrapolate APSIM results across Iowa, using a ...


Uhf Band Attenuation Through A Corn Canopy With Crop Growth, Richard Jay Cirone 2019 Iowa State University

Uhf Band Attenuation Through A Corn Canopy With Crop Growth, Richard Jay Cirone

Graduate Theses and Dissertations

Soil moisture and vegetation remote sensing measurements can be inaccurate and/or misinterpreted in the US Corn Belt, specifically when considering seasonal variation in standing vegetation. A direct crop water measurement method was employed to assist in correction of satellite measurements, specifically to SMOS and SMAP. A 433 MHz radio link was installed in a central Iowa cornfield, shortly after planting, across a distance of 50 meters, for the purpose of measuring attenuation by crop water. This experiment ran until mid grain fill, development stage R3. Vegetation water column density increased from essentially 0 at planting to just above 4 ...


Segregation Strategies For Non-Gm Corn: Improving Effectiveness Through An Analytical Modeling Approach, Chad Joseph Dolphin 2019 Iowa State University

Segregation Strategies For Non-Gm Corn: Improving Effectiveness Through An Analytical Modeling Approach, Chad Joseph Dolphin

Graduate Theses and Dissertations

The open air growing environment for corn (Zea mays L.) makes it impossible to maintain genetic purity of 100%. Much debate has characterized the discussion on acceptable tolerance levels for adventitious presence to ensure coexistence between genetically modified and non-genetically modified crops. This research analyzes nine scenarios to test field, handling, and elevator-based segregation capabilities in a commodity system. Using stochastic models to model individual factors that contribute to adventitious presence in commodity maize including: impure seed, isolation distance, equipment cleanout, and elevator handling practices, Monte Carlo simulation was used to calculate the cumulative amount of adventitious presence for each ...


The Effects Of Zinc Nanofertilizers On Tomato Plants, Ketsira Pierre 2019 University of Central Florida

The Effects Of Zinc Nanofertilizers On Tomato Plants, Ketsira Pierre

Honors Undergraduate Theses

Farmers around the world aim to use soil with adequate nutrients to produce sufficient and quality crops to the world's ever-growing population. Unbalanced use of nutrients in the soil will lead to soil deficiency, which is usually seen in South and Southeast Asian countries. This soil deficiency is often due to loss of micronutrient(s) within the soil from farming practices. Micronutrient deficiency affects not only plant growth but human health. Plants grown in nutrient deficient soil produce food with nutrient deficiencies, which affect people dependent on these foods for nutrients (Kathmandu, 2004). Nutrient deficient diseases and disorders like ...


Optimum Droplet Size Using A Pulse-Width Modulation Sprayer For Applications Of 2,4-D Choline Plus Glyphosate, Thomas R. Butts, Chase A. Samples, Lucas X. Franca, Darrin M. Dodds, Daniel B. Reynolds, Jason W. Adams, Richard K. Zollinger, Kirk A. Howatt, Bradley K. Fritz, W. Clint Hoffmann, Joe D. Luck, Greg Kruger 2019 University of Nebraska - Lincoln

Optimum Droplet Size Using A Pulse-Width Modulation Sprayer For Applications Of 2,4-D Choline Plus Glyphosate, Thomas R. Butts, Chase A. Samples, Lucas X. Franca, Darrin M. Dodds, Daniel B. Reynolds, Jason W. Adams, Richard K. Zollinger, Kirk A. Howatt, Bradley K. Fritz, W. Clint Hoffmann, Joe D. Luck, Greg Kruger

Agronomy & Horticulture -- Faculty Publications

The delivery of an optimum herbicide droplet size using pulse-width modulation (PWM) sprayers can reduce potential environmental contamination, maintain efficacy, and provide more flexible options for pesticide applicators. Field research was conducted in 2016, 2017, and 2018 across three locations (Mississippi, Nebraska, and North Dakota) for a total of 6 site-years. The objectives were to evaluate the efficacy of a range of droplet sizes (150 μm [Fine] to 900 μm [Ultra Coarse]) using a 2,4-D choline plus glyphosate pre-mixture and to create novel weed management recommendations using PWM sprayer technology. A pooled site-year generalized additive model explained less than ...


Restoring Fire-Grazer Interactions To Pursue Heterogeneity In Sandhills Prairie, Jack R. Arterburn, Dirac L. Twidwell Jr, Carissa L. Wonkka, Walter H. Schacht, David A. Wedin 2019 University of Nebraska-Lincoln

Restoring Fire-Grazer Interactions To Pursue Heterogeneity In Sandhills Prairie, Jack R. Arterburn, Dirac L. Twidwell Jr, Carissa L. Wonkka, Walter H. Schacht, David A. Wedin

Agronomy & Horticulture -- Faculty Publications

Heterogeneity has emerged as a fundamental principle for grassland management and the importance of environmental heterogeneity for biological diversity has raised questions about the appropriateness of grassland practices that seek to promote uniform grassland structure and composition. Principles of uniformity in grassland management reflect a utilitarian target of “managing for the middle” by minimizing both overgrazing and underutilization while avoiding or preventing fire and other disturbances that consume aboveground biomass. We evaluated pioneering efforts to restore fire-grazer interactions via patch burning in an effort to increase spatial heterogeneity at the patch scale in the Nebraska Sandhills, a sandy soil, mixed-grass ...


Expression Of The Arabidopsis Wrinkled 1 Transcription Factor Leads To Higher Accumulation Of Palmitate In Soybean Seed, Pamela A. Vogel, Shen Bayon de Noyer, Hyunwoo Park, Hanh Nguyen, Lili Hou, Taity Changa, Hoang Le Khang, Ozan N. Ciftci, Tong Wang, Edgar B. Cahoon, Thomas Elmo Clemente 2019 University of Nebraska - Lincoln

Expression Of The Arabidopsis Wrinkled 1 Transcription Factor Leads To Higher Accumulation Of Palmitate In Soybean Seed, Pamela A. Vogel, Shen Bayon De Noyer, Hyunwoo Park, Hanh Nguyen, Lili Hou, Taity Changa, Hoang Le Khang, Ozan N. Ciftci, Tong Wang, Edgar B. Cahoon, Thomas Elmo Clemente

Agronomy & Horticulture -- Faculty Publications

Soybean (Glycine max [L.] Merr.) is a commodity crop highly valued for its protein and oil content. The high percentage of polyunsaturated fatty acids in soybean oil results in low oxidative stability, which is a key parameter for usage in baking, high temperature frying applications, and affects shelf life of packaged products containing soybean oil. Introduction of a seed-specific expression cassette carrying the Arabidopsis transcription factor WRINKLED1 (AtWRI1) into soybean, led to seed oil with levels of palmitate up to approximately 20%. Stacking of the AtWRI1 transgenic allele with a transgenic locus harbouring the mangosteen steroyl-ACP thioesterase (GmFatA) resulted in ...


Applicability Of The Dual Isotopes Δ15n And Δ18o To Identify Nitrate In Groundwater Beneath Irrigated Cropland, R. F. Spalding, A. J. Hirsh, M. E. Exner, N. A. Little, K. L. Kloppenborg 2019 University of Nebraska - Lincoln

Applicability Of The Dual Isotopes Δ15n And Δ18o To Identify Nitrate In Groundwater Beneath Irrigated Cropland, R. F. Spalding, A. J. Hirsh, M. E. Exner, N. A. Little, K. L. Kloppenborg

Agronomy & Horticulture -- Faculty Publications

Identification of the nitrate sources that adversely impact groundwater quality is a necessary first step in the control of this major worldwide pollutant. The impact of nitrate leachate from urea-ammonium nitrate (UAN) (50% urea-N, 25% ammonium-N, 25% nitrate-N) fertilizer, whose use has increased dramatically in the last three decades largely because it can be applied through sprinkler irrigation systems to corn in all growth stages, is investigated. The dual isotopes δ15NNO3 and δ18ONO3 were measured in groundwater samples from 39 irrigation wells in two intensively sprinkler-irrigated, corn-growing areas of Nebraska with nitrate-contaminated (N > 10 ...


Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan 2019 University of Missouri

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Agronomy & Horticulture -- Faculty Publications

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset containing ...


Predicting Soil Wind Erosion Potential Under Different Corn Residue Management Scenarios In The Central Great Plains, M. K. Rakkar, Humberto Blanco-Canqui, J. Tatarko 2019 University of Minnesota

Predicting Soil Wind Erosion Potential Under Different Corn Residue Management Scenarios In The Central Great Plains, M. K. Rakkar, Humberto Blanco-Canqui, J. Tatarko

Agronomy & Horticulture -- Faculty Publications

Various models and simplified equations are available to predict wind erosion potential. However, their performance can be often site-specific, depending on soil characteristics and agronomic practices, warranting sitespecific model validations. Thus, in this study, we 1) validated the wind erodible fraction (WEF) predictive equations by Fryrear et al. (1994) and López et al. (2007) and 2) estimated the total soil loss with the Singleevent Wind Erosion Evaluation Program (SWEEP) using 3-yr measured data from six experiments located across a precipitation gradient in the central Great Plains. Each site had three corn (Zea mays L.) residue removal treatments: control (no removal ...


Ponderosa Pine Regeneration,Wildland Fuels Management, And Habitat Conservation: Identifying Trade-Offs Following Wildfire, Victoria M. Donovan, Caleb P. Roberts, Carissa L. Wonkka, David A. Wedin, Dirac L. Twidwell 2019 University of Nebraska-Lincoln

Ponderosa Pine Regeneration,Wildland Fuels Management, And Habitat Conservation: Identifying Trade-Offs Following Wildfire, Victoria M. Donovan, Caleb P. Roberts, Carissa L. Wonkka, David A. Wedin, Dirac L. Twidwell

Agronomy & Horticulture -- Faculty Publications

Increasing wildfires in western North American conifer forests have led to debates surrounding the application of post-fire management practices. There is a lack of consensus on whether (and to what extent) post-fire management assists or hinders managers in achieving goals, particularly in under-studied regions like eastern ponderosa pine forests. This makes it difficult for forest managers to balance among competing interests. We contrast structural and community characteristics across unburned ponderosa pine forest, severely burned ponderosa pine forest, and severely burned ponderosa pine forest treated with post-fire management with respect to three management objectives: ponderosa pine regeneration, wildland fuels control, and ...


Beyond Bird Feed: Proso Millet For Human Health And Environment, Saurav Das, Rituraj Khound, Meenakshi Santra, Dipak K. Santra 2019 University of Nebraska - Lincoln

Beyond Bird Feed: Proso Millet For Human Health And Environment, Saurav Das, Rituraj Khound, Meenakshi Santra, Dipak K. Santra

Agronomy & Horticulture -- Faculty Publications

Domesticated in 8000–10,000 BP in northern China, proso millet (Panicum miliaceum L.) is the best adaptive rotational crop for semiarid central High Plains of the USA, where average annual precipitation is 356–407 mm. Proso millet has multiple benefits when consumed as human food. Proso millet is rich in minerals, dietary fiber, polyphenols, vitamins and proteins. It is gluten-free and therefore, ideal for the gluten intolerant people. Proso millet contains high lecithin which supports the neural health system. It is rich in vitamins (niacin, B-complex vitamins, folic acid), minerals (P, Ca, Zn, Fe) and essential amino acids (methionine ...


A Key Variant In The Cis-Regulatory Element Of Flowering Gene Ghd8 Associated With Cold Tolerance In Rice, Peng Wang, Yin Xiong, Rong Gong, Ying Yang, Kai Fan, Sibin Yu 2019 Huazhong Agricultural University

A Key Variant In The Cis-Regulatory Element Of Flowering Gene Ghd8 Associated With Cold Tolerance In Rice, Peng Wang, Yin Xiong, Rong Gong, Ying Yang, Kai Fan, Sibin Yu

Agronomy & Horticulture -- Faculty Publications

Variations in the gene promoter play critical roles in the evolution of important adaptive traits in crops, but direct links of the regulatory mutation to the adaptive change are not well understood. Here, we examine the nucleotide variations in the promoter region of a transcription factor (Ghd8) that control grain number, plant height and heading date in rice. We find that a dominant promoter type of subspecies japonica displayed a high activity for Ghd8 expression in comparison with the one in indica. Transgenic analyses revealed that higher expression levels of Ghd8 delayed heading date and enhanced cold tolerance in rice ...


A Tmeff2-Regulated Cell Cycle Derived Gene Signature Is Prognostic Of Recurrence Risk In Prostate Cancer, Constantin Georgescu, Joshua M. Corbin, Sandra Thibivilliers, Zachary D. Webb, Yan D. Zhao, Jan Koster, Kar-Ming Fung, Adam S. Asch, Jonathan D. Wren, Maria J. Ruiz-Echevarria 2019 Oklahoma Medical Research Foundation

A Tmeff2-Regulated Cell Cycle Derived Gene Signature Is Prognostic Of Recurrence Risk In Prostate Cancer, Constantin Georgescu, Joshua M. Corbin, Sandra Thibivilliers, Zachary D. Webb, Yan D. Zhao, Jan Koster, Kar-Ming Fung, Adam S. Asch, Jonathan D. Wren, Maria J. Ruiz-Echevarria

Agronomy & Horticulture -- Faculty Publications

Background: The clinical behavior of prostate cancer (PCa) is variable, and while the majority of cases remain indolent, 10% of patients progress to deadly forms of the disease. Current clinical predictors used at the time of diagnosis have limitations to accurately establish progression risk. Here we describe the development of a tumor suppressor regulated, cell-cycle gene expression based prognostic signature for PCa, and validate its independent contribution to risk stratification in several radical prostatectomy (RP) patient cohorts.

Methods: We used RNA interference experiments in PCa cell lines to identify a gene expression based gene signature associated with Tmeff2, an androgen ...


Generating High Density, Low Cost Genotype Data In Soybean [Glycine Max (L.) Merr.], Mary M. Happ, Haichuan Wang, George L. Graef, David L. Hyten 2019 University of Nebraska - Lincoln

Generating High Density, Low Cost Genotype Data In Soybean [Glycine Max (L.) Merr.], Mary M. Happ, Haichuan Wang, George L. Graef, David L. Hyten

Agronomy & Horticulture -- Faculty Publications

Obtaining genome-wide genotype information for millions of SNPs in soybean [Glycine max (L.) Merr.] often involves completely resequencing a line at 5X or greater coverage. Currently, hundreds of soybean lines have been resequenced at high depth levels with their data deposited in the NCBI Short Read Archive. This publicly available dataset may be leveraged as an imputation reference panel in combination with skim (low coverage) sequencing of new soybean genotypes to economically obtain high-density SNP information. Ninety-nine soybean lines resequenced at an average of 17.1X were used to generate a reference panel, with over 10 million SNPs called using ...


Impact Of Hurricane Katrina On The Coastal Systems Of Southern Louisiana, Wen-Ching Chuang, Tarsha Eason, Ahjond Garmestani, Caleb Roberts 2019 Miami University - Oxford

Impact Of Hurricane Katrina On The Coastal Systems Of Southern Louisiana, Wen-Ching Chuang, Tarsha Eason, Ahjond Garmestani, Caleb Roberts

Agronomy & Horticulture -- Faculty Publications

Natural disasters, such as hurricanes and forest fires, could trigger collapse and reorganization of social-ecological systems. In the face of external perturbations, a resilient system would have capacity to absorb impacts, adapt to change, learn, and if needed, reorganize within the same regime. Within this context, we asked how human and natural systems in Louisiana responded to Hurricane Katrina, and how the natural disaster altered the status of these systems. This paper discusses community resilience to natural hazards and addresses the limitations for assessing disaster resilience. Furthermore, we assessed social and environmental change in New Orleans and southern Louisiana through ...


Genome-Wide Association Study For Multiple Biotic Stress Resistance In Synthetic Hexaploid Wheat, Madhav Bhatta, Alexey Morgounov, Vikas Belamkar, Stephen N. Wegulo, Abdelfattah A. Dababat, Gul Erginbas-Orakci, Mustapha El Bouhssini, Pravin Gautam, Jesse Poland, Nilufer Akci, Lutfu Demir, Ruth Wanyera, P. Stephen Baenziger 2019 University of Nebraska - Lincoln

Genome-Wide Association Study For Multiple Biotic Stress Resistance In Synthetic Hexaploid Wheat, Madhav Bhatta, Alexey Morgounov, Vikas Belamkar, Stephen N. Wegulo, Abdelfattah A. Dababat, Gul Erginbas-Orakci, Mustapha El Bouhssini, Pravin Gautam, Jesse Poland, Nilufer Akci, Lutfu Demir, Ruth Wanyera, P. Stephen Baenziger

Agronomy & Horticulture -- Faculty Publications

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2n = 6x = 42, AABBDD, Triticum aestivum L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; Puccinia triticina, stem; P. graminis f.sp. tritici, and stripe; P. striiformis f.sp. tritici) and crown rot (Fusarium spp.); cereal cyst nematode ...


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