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Full-Text Articles in Bioresource and Agricultural Engineering

Shear Strength Of Coal Combustion Product By Vane Shear, Wesley J. Herweynen, Christopher A. Bareither, Joseph Scalia Jan 2019

Shear Strength Of Coal Combustion Product By Vane Shear, Wesley J. Herweynen, Christopher A. Bareither, Joseph Scalia

Coal Combustion and Gasification Products Journal Archive

The objective of this study was to evaluate the shear strength of a coal combustion product (CCP) by using the vane shear test. A series of small-scale vane shear (SS-VS; diameter = 12.7 mm and height = 25.4 mm) and large-scale vane shear (LS-VS; diameter = 25 mm and height = 50 mm) laboratory tests were conducted. Undrained and drained strength envelopes were determined using consolidated undrained triaxial compression tests, and drained strength was checked via consolidated drained direct shear. In addition, effects of (1) rate of vane rotation, (2) time delay between vane insertion and beginning rotation, and (3) …


Mineralogy And Geochemistry Of Feed Coals And Combustion Residues From Tunçbilek And Seyitömer Coal-Fired Power Plants In Western Turkey, Ali Ihsan Karayigit, Ozlem Yigitler, Seda Iserli, Xavier Querol, Maria Mastalerz, Riza Gorkem Oskay, James C. Hower Jan 2019

Mineralogy And Geochemistry Of Feed Coals And Combustion Residues From Tunçbilek And Seyitömer Coal-Fired Power Plants In Western Turkey, Ali Ihsan Karayigit, Ozlem Yigitler, Seda Iserli, Xavier Querol, Maria Mastalerz, Riza Gorkem Oskay, James C. Hower

Coal Combustion and Gasification Products Journal Archive

This study focuses on the enrichment of elements in feed coal (FC) and combustion residues, namely, fly ash (FA) and bottom ash (BA) samples, picked up from the Tunçbilek and Seyitömer coal-fired power plants in western Turkey. The FCs in both plants have generally similar mineralogical compositions, although siderite and dolomite are more prominent in Tunçbilek and feldspar and pyrite are more abundant in Seyitömer. Minerals in the FA from both power plants are mainly quartz, hematite, magnetite, anhydrite, and mullite. Along with quartz, the Fe-oxides are dominant phases in the BA samples. Accessory minerals in the FCs, FAs, and …


Phaselous Vulgaris Growth Under The Influence Of Manufactured Coal Ash Aggregates, Sangchul Hwang, Imiraily Hernandez, Isomar Latorre, Sahid Rosado Jan 2019

Phaselous Vulgaris Growth Under The Influence Of Manufactured Coal Ash Aggregates, Sangchul Hwang, Imiraily Hernandez, Isomar Latorre, Sahid Rosado

Coal Combustion and Gasification Products Journal Archive

Manufactured coal ash aggregates (MAs) are a 2:1 (w/w) solidified composite of fly and bottom ash. The current study assessed the feasibility of beneficial utilization of MAs as a subsoil substitute for open-pit restoration to phyto-viable land. A series of indoor and outdoor experiments examined Phaselous vulgaris growth under the influence of MAs in the soil environment. With the MAs layer below the topsoil, P. vulgaris showed enhanced growth with respect to shoot height, leaf number, and leaf chlorophyll intensity. Similar growth enhancement was observed when the MAs were mixed with topsoil or applied as a micronutrient source over the …


Using The Conceptual Site Model To Efficiently And Effectively Implement Groundwater Monitoring And Corrective Action At Coal Combustion Residual Sites†, Carla Landrum, Jim Feild, Tim Glover, Alison Dunn Jan 2019

Using The Conceptual Site Model To Efficiently And Effectively Implement Groundwater Monitoring And Corrective Action At Coal Combustion Residual Sites†, Carla Landrum, Jim Feild, Tim Glover, Alison Dunn

Coal Combustion and Gasification Products Journal Archive

On 19 October 2015, the Disposal of Coal Combustion Residuals (CCRs) for Electric Utilities final rule (CCR Rule), issued by the U.S. Environmental Protection Agency (US EPA) under Subtitle D of the Recovery and Conservation Act (RCRA), became effective. The Groundwater Monitoring and Corrective Action subsections of the CCR Rule (40 CFR §§ 257.90–257.98) set out strict requirements for groundwater monitoring at the detection and assessment levels, followed by (if necessary) groundwater characterization in support of corrective measures assessment. Since the federal CCR Rule was implemented, the US EPA has proposed and finalized some amendments, and some states have proposed …


The Role Of Ash Mineralogy On Breakthrough Pressure And Contact Angle: A Statistical Evaluation, Jenberu L. Feyyisa, John L. Daniels Jan 2019

The Role Of Ash Mineralogy On Breakthrough Pressure And Contact Angle: A Statistical Evaluation, Jenberu L. Feyyisa, John L. Daniels

Coal Combustion and Gasification Products Journal Archive

One method to minimize contaminant leaching from coal fly ash (CFA) involves modifying its surface to become water repellent. Five types of CFA, CFA-1, CFA-2, CFA-3, CFA-5, and CFA-6, were modified by three organosilane (OS) products at different mix ratios. Multiple breakthrough pressure (BP) experiments were conducted for different samples at different mix ratios to identify the performance of the modified surface to resist a positive water entry pressure. The contribution of oxides and minerals in CFA to form a water-repellent surface were analyzed without considering OS effects. Results showed that semi-log–transformed regression models can effectively establish the relationship between …


South Africa’S Power Producer’S Revised Coal Ash Strategy And Implementation Progress, Kelley Reynolds-Clausen, Nico Singh Jan 2019

South Africa’S Power Producer’S Revised Coal Ash Strategy And Implementation Progress, Kelley Reynolds-Clausen, Nico Singh

Coal Combustion and Gasification Products Journal Archive

The South African electricity public utility Eskom has embarked on a process to increase utilisation of the ash produced through the electricity generation process at its coal-fired power stations. In the 2014–2015 financial year, 119.2 million tons of coal was consumed, producing 34.4 million tons (28.9%) of ash. About 7% of the Eskom ash is sold from 6 of the 13 coal-fired power stations. Many stations are currently running out of ash storage space, and expansion of the ash disposal facilities is required, which could affect security of supply because of limited ashing areas. Additionally, legislative requirements lead to extra …


Variability Of E. Coli In Streambed Sediments And Its Implication For Water Quality, Sadia Salam Jan 2019

Variability Of E. Coli In Streambed Sediments And Its Implication For Water Quality, Sadia Salam

Electronic Theses and Dissertations

Fecal indicator bacteria (FIB), including E. coli, are the number one cause of water quality impairments in the United States according to the USEPA. FIB are used as a predictor to identify the possible presence of pathogens in waterbodies. E. coli is a useful indicator of gastrointestinal (GI) related illnesses from contact with fresh water. While surface water is routinely monitored for water quality, streambed sediments are rarely considered as a source of FIB to the overlying water column. This study focuses on understanding the variation of E. coli concentrations in streambed sediments and the potential impact of sediment sources …


The Effect Of Edge-Of-Field Nutrient Management Practices On Microbial Concentrations In Subsurface Drainage Water And The Associated Risk Of Antibiotic Resistance Dissemination, Sara Mardani Jan 2019

The Effect Of Edge-Of-Field Nutrient Management Practices On Microbial Concentrations In Subsurface Drainage Water And The Associated Risk Of Antibiotic Resistance Dissemination, Sara Mardani

Electronic Theses and Dissertations

Many in-field and edge-of-field management practices have been used to reduce nutrient loads from agricultural fields. The denitrification woodchip bioreactor (WB) is one edgeof- field management practice that has proven to be effective in removing nitrate from subsurface drainage water. The success in nitrate removal achieved with WBs has raised interest in expanding their capabilities for removing other agricultural pollutants, including phosphorus, by using other types of media like phosphorus-sorbing filters or combining these filters with woodchips to remove both nitrate and phosphorus as dual-nutrient removal systems. Despite the extensive research done on WBs and nutrient filter materials, little consideration …


Actual Evapotranspiration And Crop Coefficients Of Irrigated Lowland Rice (Oryza Sativa L.) Under Semiarid Climate, Koffi Djaman, Daran R. Rudnick, Yonnelle D. Moukoumbi, Abdoulaye Sow, Suat Irmak Jan 2019

Actual Evapotranspiration And Crop Coefficients Of Irrigated Lowland Rice (Oryza Sativa L.) Under Semiarid Climate, Koffi Djaman, Daran R. Rudnick, Yonnelle D. Moukoumbi, Abdoulaye Sow, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Lowland irrigated rice is the predominant crop produced in the Senegal River Valley characterized by very low annual rainfall, high temperatures, and low relative humidity. The Senegal River is shared by Senegal, Mali, Mauritania, and Guinea, and serves as the main source of irrigation water for the adopted double rice cropping system. Developing appropriate resource management strategies might be the key factor for the sustainability of rice production in the region. This study aims to estimate rice seasonal evapotranspiration (ETa), irrigation water requirement, and to develop rice growth stage specific crop coefficients (Kc) to improve rice water productivity. Field experiments …


Design Of Plant Protection Uav Variable Spray System Based On Neural Networks, Sheng Wen, Quanyong Zhang, Xuanchun Yin, Yubin Lan, Jiantao Zhang, Yufeng Ge Jan 2019

Design Of Plant Protection Uav Variable Spray System Based On Neural Networks, Sheng Wen, Quanyong Zhang, Xuanchun Yin, Yubin Lan, Jiantao Zhang, Yufeng Ge

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Recently, unmanned aerial vehicles (UAVs) have rapidly emerged as a new technology in the fields of plant protection and pest control in China. Based on existing variable spray research, a plant protection UAV variable spray system integrating neural network based decision making is designed. Using the existing data on plant protection UAV operations, combined with artificial neural network (ANN) technology, an error back propagation (BP) neural network model between the factors affecting droplet deposition is trained. The factors affecting droplet deposition include ambient temperature, ambient humidity, wind speed, flight speed, flight altitude, propeller pitch, nozzles pitch and prescription value. Subsequently, …


Genetic Diversity And Population Structure Of A Camelina Sativa Spring Panel, Zinan Luo, Jordan Brock, John M. Dyer, Toni Kutchan, Daniel P. Schachtman, Megan Augustin, Yufeng Ge, Noah Fahlgren, Hussein Abdel-Haleem Jan 2019

Genetic Diversity And Population Structure Of A Camelina Sativa Spring Panel, Zinan Luo, Jordan Brock, John M. Dyer, Toni Kutchan, Daniel P. Schachtman, Megan Augustin, Yufeng Ge, Noah Fahlgren, Hussein Abdel-Haleem

Department of Agricultural and Biological Systems Engineering: Faculty Publications

There is a need to explore renewable alternatives (e.g., biofuels) that can produce energy sources to help reduce the reliance on fossil oils. In addition, the consumption of fossil oils adversely affects the environment and human health via the generation of waste water, greenhouse gases, and waste solids. Camelina sativa, originated from southeastern Europe and southwestern Asia, is being re-embraced as an industrial oilseed crop due to its high seed oil content (36–47%) and high unsaturated fatty acid composition (>90%), which are suitable for jet fuel, biodiesel, high-value lubricants and animal feed. C. sativa’s agronomic advantages include …


Nucleic Acid Delivery To Mesenchymal Stem Cells: A Review Of Nonviral Methods And Applications, Andrew Hamann, Albert Nguyen, Angela K. Pannier Jan 2019

Nucleic Acid Delivery To Mesenchymal Stem Cells: A Review Of Nonviral Methods And Applications, Andrew Hamann, Albert Nguyen, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background: Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated and expanded from many tissues, and are being investigated for use in cell therapies. Though MSC therapies have demonstrated some success, none have been FDA approved for clinical use. MSCs lose stemness ex vivo, decreasing therapeutic potential, and face additional barriers in vivo, decreasing therapeutic efficacy. Culture optimization and genetic modification of MSCs can overcome these barriers. Viral transduction is efficient, but limited by safety concerns related to mutagenicity of integrating viral vectors and potential immunogenicity of viral antigens. Nonviral delivery methods are safer, though limited …


Water Effects On Optical Canopy Sensing For Late-Season Site-Specific Nitrogen Management Of Maize, Tsz Him Lo, Daran Rudnick, Brian Krienke, D. M. Heeren, Yufeng Ge, Tim M. Shaver Jan 2019

Water Effects On Optical Canopy Sensing For Late-Season Site-Specific Nitrogen Management Of Maize, Tsz Him Lo, Daran Rudnick, Brian Krienke, D. M. Heeren, Yufeng Ge, Tim M. Shaver

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The interpretation of optical canopy sensor readings for determining optimal rates of late-season site-specific nitrogen application to corn (Zea mays L.) can be complicated by spatially variable water sufficiency, which can also affect canopy size and/or pigmentation. In 2017 and 2018, corn following corn and corn following soybeans were subjected to irrigation×nitrogen fertilizer treatments in west central Nebraska, USA, to induce variable water sufficiency and variable nitrogen sufficiency. The vegetation index-sensor combinations investigated were the normalized difference vegetation index (NDVI), the normalized difference red edge index (NDRE), and the reflectance ratio of near infrared minus red edge over near …


Principal Variable Selection To Explain Grain Yield Variation In Winter Wheat From Features Extracted From Uav Imagery, Jiating Li, Arun-Narenthiran Veeranampalayam-Sivakumar, Madhav Bhatta, Nicholas D. Garst, Hannah Stoll, P. Stephen Baenziger, Vikas Belamkar, Reka Howard, Yufeng Ge, Jiating Li Jan 2019

Principal Variable Selection To Explain Grain Yield Variation In Winter Wheat From Features Extracted From Uav Imagery, Jiating Li, Arun-Narenthiran Veeranampalayam-Sivakumar, Madhav Bhatta, Nicholas D. Garst, Hannah Stoll, P. Stephen Baenziger, Vikas Belamkar, Reka Howard, Yufeng Ge, Jiating Li

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background: Automated phenotyping technologies are continually advancing the breeding process. However, collecting various secondary traits throughout the growing season and processing massive amounts of data still take great efforts and time. Selecting a minimum number of secondary traits that have the maximum predictive power has the potential to reduce phenotyping efforts. The objective of this study was to select principal features extracted from UAV imagery and critical growth stages that contributed the most in explaining winter wheat grain yield. Five dates of multispectral images and seven dates of RGB images were collected by a UAV system during the spring growing …


Agenator: An Open Source Computer-Controlled Dry Aging System For Beef, Soon Kiat Lau, Felipe Azevedo Ribeiro, Jeyamkondan Subbiah, Chris R. Calkins Jan 2019

Agenator: An Open Source Computer-Controlled Dry Aging System For Beef, Soon Kiat Lau, Felipe Azevedo Ribeiro, Jeyamkondan Subbiah, Chris R. Calkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Dry aging of beef is a process where beef is exposed to a controlled environment with the ultimate goal of drying the beef to improve its quality and value. Comprehensive investigations into the effects of various environmental conditions on dry aging are crucial for understanding and optimizing the process, but the lack of affordable equipment focused on data collection makes it difficult to do so. The Agenator was thus developed as an open source system with a suite of features for investigating dry aging such as: measuring and recording relative humidity, temperature, mass, air velocity, and fan rotational speed; precise …


Early Prediction Of Soybean Traits Through Color And Texture Features Of Canopy Rgb Imagery, Wenan Yuan, Nuwan Kumara Wijewardane, Shawn Jenkins, Geng Bai, Yufeng Ge, George L. Graef Jan 2019

Early Prediction Of Soybean Traits Through Color And Texture Features Of Canopy Rgb Imagery, Wenan Yuan, Nuwan Kumara Wijewardane, Shawn Jenkins, Geng Bai, Yufeng Ge, George L. Graef

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Global crop production is facing the challenge of a high projected demand, while the yields of major crops are not increasing at sufficient speeds. Crop breeding is an important way to boost crop productivity, however its improvement rate is partially hindered by the long crop generation cycles. If end-season crop traits such as yield can be predicted through early-season phenotypic measurements, crop selection can potentially be made before a full crop generation cycle finishes. This study explored the possibility of predicting soybean end-season traits through the color and texture features of early-season canopy images. Six thousand three hundred and eighty-three …


Heterologous Expression And Functional Characterization Of A Gh10 Endoxylanase From Aspergillus Fumigatus Var. Niveus With Potential Biotechnological Application, Josman Velasco, Bianca Oliva, Evandro Jose Mulinari, Leidy Patricia Quintero, Awana Da Silva Lima, Aline Larissa Goncalves, Thiago Augusto Goncalves, Andre Damasio, Fabio Marcio Squina, Adriane Maria Ferreira Milagres, Asmaa Abdella, Mark R. Wilkins, Fernando Segato Jan 2019

Heterologous Expression And Functional Characterization Of A Gh10 Endoxylanase From Aspergillus Fumigatus Var. Niveus With Potential Biotechnological Application, Josman Velasco, Bianca Oliva, Evandro Jose Mulinari, Leidy Patricia Quintero, Awana Da Silva Lima, Aline Larissa Goncalves, Thiago Augusto Goncalves, Andre Damasio, Fabio Marcio Squina, Adriane Maria Ferreira Milagres, Asmaa Abdella, Mark R. Wilkins, Fernando Segato

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from Aspergillus fumigatus var. niveus (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60°C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMNGH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 …


Antibiotic Resistance Gene Profile Changes In Cropland Soil After Manure Application And Rainfall, Morgan Meyers, Lisa Durso, John E. Gilley, Heidi Waldrip, Lana Castleberry, Amy Millmier Schmidt Jan 2019

Antibiotic Resistance Gene Profile Changes In Cropland Soil After Manure Application And Rainfall, Morgan Meyers, Lisa Durso, John E. Gilley, Heidi Waldrip, Lana Castleberry, Amy Millmier Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Land application of manure introduces gastrointestinal microbes into the environment, including bacteria carrying antibiotic resistance genes (ARGs). Measuring soil ARGs is important for active stewardship efforts to minimize gene flow from agricultural production systems; however, the variety of sampling protocols and target genes makes it difficult to compare ARG results between studies. We used polymerase chain reaction (PCR) methods to characterize and/or quantify 27 ARG targets in soils from 20 replicate, long-term no-till plots, before and after swine manure application and simulated rainfall and runoff. All samples were negative for the 10 b-lactamase genes assayed. For tetracycline resistance, only source …


Optimization Of Process Parameters And Fermentation Strategy For Xylanase Production In A Stirred Tank Reactor Using A Mutant Aspergillus Nidulans Strain, Asmaa Abdella, Fernando Segato, Mark R. Wilkins Jan 2019

Optimization Of Process Parameters And Fermentation Strategy For Xylanase Production In A Stirred Tank Reactor Using A Mutant Aspergillus Nidulans Strain, Asmaa Abdella, Fernando Segato, Mark R. Wilkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The present work studied the optimization of aeration rate, agitation rate and oxygen transfer and the use of various batch fermentation strategies for xylanase production from a recombinant Aspergillus nidulans strain in a 3 L stirred tank reactor. Maximum xylanase production of 1250 U/mL with productivity of 313 U/mL/day was obtained under an aeration rate of 2 vvm and an agitation rate of 400 rpm using batch fermentation. The optimum volumetric oxygen transfer coefficient (kLa) for efficient xylanase production was found to be 38.6 h-1. Fed batch mode and repeated batch fermentation was also performed with kLa was 38.6 h …


System For Optimizing Fed-Batch Hydrolysis Of Biomass, Chao Tai, Deepak R. Keshwani Jan 2019

System For Optimizing Fed-Batch Hydrolysis Of Biomass, Chao Tai, Deepak R. Keshwani

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Provided herein is a system for optimizing the fed-batch hydrolysis of biomass.


Improving Retrievals Of Crop Vegetation Parameters From Remote Sensing Data, Nathaniel Levitan Jan 2019

Improving Retrievals Of Crop Vegetation Parameters From Remote Sensing Data, Nathaniel Levitan

Dissertations and Theses

Agricultural systems are difficult to model because crop growth is driven by the strongly nonlinear interaction of Genotype x Environment x Management (G x E x M) factors. Due to the nonlinearity in the interaction of these factors, the amount of data necessary to develop and utilize models to accurately predict the performance of agricultural systems at an operational scale is large. Satellite remote sensing provides the potential to vastly increase the amount of data available for modelling agricultural systems as a result of its high revisit time and spatial coverage. Unfortunately, there have been significant difficulties in deploying remote …


Comparative Analysis Of Mosquito Trap Counts In The Peruvian Amazon: Effect Of Trap Type And Other Covariates On Counts And Diversity, George W. Peck, Fanny Castro-Llanos, Victor Lopez-Sifuentes, Erica Lindroth Dec 2018

Comparative Analysis Of Mosquito Trap Counts In The Peruvian Amazon: Effect Of Trap Type And Other Covariates On Counts And Diversity, George W. Peck, Fanny Castro-Llanos, Victor Lopez-Sifuentes, Erica Lindroth

Civil and Environmental Engineering Faculty Publications and Presentations

Efficient detection of multiple species of adult mosquitoes in various habitats using effective traps is a crucial 1st step in any disease prevention program. Novel trap types that target tropical vectors of human diseases require field testing in the habitat of the vector–disease system in question. This paper analyzes a series of mosquito trapping studies conducted at Mapacocha, San Juan Bautista District, Loreto, Peru, during August–September 2013 and April–May 2014. Six trap configurations were evaluated in forest and rural locations. Adult mosquito counts were analyzed using full Bayesian inference of multilevel generalized linear models and posterior probability point estimates of …


Invasion Of The P Elements: Tolerance Is Not Futile, Colin D. Meiklejohn, Justin P. Blumenstiel Oct 2018

Invasion Of The P Elements: Tolerance Is Not Futile, Colin D. Meiklejohn, Justin P. Blumenstiel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Organisms are locked in an eternal struggle with parasitic DNA sequences that live inside their genomes and wreak havoc on their host’s chromosomes as they spread through populations. To combat these parasites, host species have evolved elaborate mechanisms of resistance that suppress their activity. A new study in Drosophila indicates that, prior to the acquisition of resistance, individuals can vary in their ability to tolerate the activity of these genomic parasites, ignoring or repairing the damage they induce. This tolerance results from variation at genes involved in germline development and DNA damage checkpoints and suggests that these highly conserved cellular …


Causal Loop Development Activity, Ali Mirchi Aug 2018

Causal Loop Development Activity, Ali Mirchi

All ECSTATIC Materials

Students will work in groups to develop a causal loop diagram (CLD) to illustrate the structure and expected behavior of the fictional water short state of Nevizonato facilitate qualitative discussion of expected outcomes of a proposed water management strategy. This activity requires familiarity with systems thinking and system dynamics modeling. CLDs are introduced as a fundamental systems thinking tool for conceptual modeling.


Cover Crops Have Negligible Impact On Soil Water In Nebraska Maize–Soybean Rotation, J. Burdette Barker, Derek M. Heeren, Katja Koehler-Cole, Charles Shapiro, Humberto Blanco-Canqui, Roger W. Elmore, Christopher A. Proctor, Suat Irmak, Charles A. Francis, Tim M. Shaver, Ali T. Mohammed Aug 2018

Cover Crops Have Negligible Impact On Soil Water In Nebraska Maize–Soybean Rotation, J. Burdette Barker, Derek M. Heeren, Katja Koehler-Cole, Charles Shapiro, Humberto Blanco-Canqui, Roger W. Elmore, Christopher A. Proctor, Suat Irmak, Charles A. Francis, Tim M. Shaver, Ali T. Mohammed

Department of Agricultural and Biological Systems Engineering: Faculty Publications

One perceived cost of integrating winter cover cropping in maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] rotation systems is the potential negative impact on soil water storage available for primary crop production. The objective of this 3-year study was to evaluate the effects of winter cover crops on soil water storage and cover crop biomass production following no-till maize and soybean rotations. Locations were near Brule (west-central), Clay Center (south-central), Concord (northeast), and Mead (east-central), Nebraska, United States. Treatments included crop residue only (no cover crop) and a multi-species cover crop mix, both broadcast-seeded before …


Plant Community Composition, Floristic Quality, And Establishment Of Roadside Revegetation In Nebraska, Usa, Jonathan M. Soper Jul 2018

Plant Community Composition, Floristic Quality, And Establishment Of Roadside Revegetation In Nebraska, Usa, Jonathan M. Soper

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Roadside revegetation poses a challenge and opportunity for biodiversity conservation, as the land area occupied by roadsides is not expected to decline in the future. In the context of roadside revegetation activities in rural regions dominated by agricultural land uses, revegetation efforts can establish plant communities that offer unique species that would otherwise be absent on the landscape. To determine the efficacy of roadside revegetation efforts in 1) providing plant communities of high biodiversity value and 2) meeting the expectations of roadside revegetation managers for establishment, we quantified botanical composition, floristic quality, and success in seeding efforts to meet manager …


Tradeoffs In Model Performance And Effort For Long-Term Phosphorus Leaching Based On In Situ Field Data, Ryan P. Freiberger, Derek M. Heeren, Dean E. Eisenhauer, Aaron R. Mittelstet, Guillermo Baigorria Jun 2018

Tradeoffs In Model Performance And Effort For Long-Term Phosphorus Leaching Based On In Situ Field Data, Ryan P. Freiberger, Derek M. Heeren, Dean E. Eisenhauer, Aaron R. Mittelstet, Guillermo Baigorria

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Phosphorus and N are critical nutrients for agriculture but are also responsible for surface water enrichment that leads to toxic algal growth. Although P loading to surface waters has traditionally been thought to occur primarily in surface runoff, contributions from subsurface transport can also be significant. The primary objectives of this research were to evaluate several methods of representing macropore flow and transport in a finite element model using plot-scale infiltration and leaching data and to compare several models of various levels of complexity to simulate long-term P leaching. To determine flow and transport parameters, single- and dual-porosity models in …


Portable Flux Tower Deployments Field Campaign Report, M. S. Torn, L Kuepper, S. C. Biraud, D. P. Billesbach Jun 2018

Portable Flux Tower Deployments Field Campaign Report, M. S. Torn, L Kuepper, S. C. Biraud, D. P. Billesbach

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Contents

Acronyms and Abbreviations...................................................................... iii

1.0 Summary ....................................................... 1

2.0 Results ........................................... 1

3.0 Publications and References ................................................. 2

4.0 Lessons Learned .................................................................... 2


U.S. Agro-Climate In 20th Century: Growing Degree Days, First And Last Frost, Growing Season Length, And Impacts On Crop Yields, Meetpal Singh Kukal, Suat Irmak May 2018

U.S. Agro-Climate In 20th Century: Growing Degree Days, First And Last Frost, Growing Season Length, And Impacts On Crop Yields, Meetpal Singh Kukal, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Significant air temperature changes have occurred globally during the 20th century, which are spatially variable to a considerable degree and these changes can have substantial implications in agroecosystem productivity. The agroclimate indicators that are responsible in these contexts are first fall frost (FFF), last spring frost (LSF), climatological growing season (CGS) length, and heat accumulation (growing degree days, GDD). We explore spatial and temporal trends associated with these indices across the continental U.S. (CONUS) during 1900–2014 using datasets collected at 1218 sites. On average, FFF has been occurring later (by 5.4 days century−1), and LSF has been occurring …


Development Of A Digital Rain-Sensing Irrigation Pump Controller And An Android Enabled Bluetooth Paddlewheel Flowmeter, Jayendra Mishra May 2018

Development Of A Digital Rain-Sensing Irrigation Pump Controller And An Android Enabled Bluetooth Paddlewheel Flowmeter, Jayendra Mishra

Graduate Theses and Dissertations

For better irrigation efficiency, it is recommended that farmers track their water consumption to avoid over-irrigating. However, it is difficult to implement this as it is labor intensive to supervise pumps manually and available technologies require high investment. Therefore, a rain sensing pump controller for 3-phase electric irrigation pumps and a stand-alone portable Android enabled paddlewheel flowmeter has been developed to test their feasibility.

The pump timer is a retrofit device for irrigation pump panels. The controller allows an irrigator to start and stop the pump with less supervision. An infrared rain sensor is integrated with the controller to measure …