Agricultural Science Commons^™

Building A Community Modelling And Information Sharing Culture, A. Voinov, R. R. Hood, J. D. Daues, H. Assaf, R. Stewart

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

Much of human creativity is geared towards moving energy and materials rather than information, even though information has become another crucial component of human welfare and livelihood. Information, unlike energy and materials, is not subject to conservation laws. By copying information from sources and distributing it to new destinations we do not lose information at the sources. This is what is known as non-rival goods in ecological economics (Daly and Farley, 2003). As with gravity, by using information we do not decrease the ability of others to use it. Nevertheless, exchange of information is restricted by patent law, as well …

Comparison Of Field Measured Soil Absorption Field Loading Rates And Loading Rates Estimated From Soil Morphologic Properties, Kelli S. Hart, Brad D. Lee, Philip J. Schoeneberger, Donald P. Franzmeier, Phillip R. Owens, Douglas R. Smith

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

Concerns from local health departments regarding premature septic system failure (less than 1 year from installation) has led to an investigation of septic system soil absorption field design parameters in northeast Indiana. The objective of this study was to compare the loading rate based on field measured saturated hydraulic conductivity (LR_m) across a toposequence to the estimated allowable loading rate (LR_e) based on soil morphological properties. Saturated hydraulic conductivity measurements were determined by a compact constant-head permeameter at five landscape positions, at four depths (surface horizon, upper argillic horizon, transition zone between the argillic horizon and …

Modeling Trench Sidewall And Bottom Flow In On-Site Wastewater Systems, S. D. Finch, D. E. Radcliffe, L. T. West

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

Little is known about how much wastewater infiltrates the soil via the trench sidewall versus the trench bottom in on-site wastewater systems. Our objectives were to develop a method of simulating trench bottom and sidewall flow using a two-dimensional numerical computer model that would include the trench within the model space and determine how much sidewall flow would occur under steady-state conditions. We used HYDRUS-2D to simulate water flow in a two-dimensional cross section of a conventional gravel-filled trench and the surrounding drainfield.

Numerical Modeling Of Bank Instability By Seepage Erosion Undercutting Of Layered Streambanks, M. L. Chu-Agor, G. V. Wilson, G. A. Fox

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

Undercutting, primarily considered due to fluvial mechanisms, has been reported to have a major impact on slope failure. Predicting bank collapse specifically due to seepage erosion undercutting by particle mobilization on layered streambanks has not been fully studied or modeled, even though its role in streambank erosion may be important. The limitation originates from the limited field measurements or laboratory experiments as well as the unavailability of discrete element models that can effectively simulate seepage particle mobilization, undercutting, and the corresponding mass wasting. The objective of this research was to demonstrate a procedure for incorporating seepage undercutting into bank stability …

Genomic Analysis Of Fusarium Verticillioides, D. W. Brown, R. A.E. Butchko, R. H. Proctor

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

Fusarium verticillioides (teleomorph Gibberella moniliformis) can be either an endophyte of maize, causing no visible disease, or a pathogen-causing disease of ears, stalks, roots and seedlings. At any stage, this fungus can synthesize fumonisins, a family of mycotoxins structurally similar to the sphingolipid sphinganine. Ingestion of fumonisin-contaminated maize has been associated with a number of animal diseases, including cancer in rodents, and exposure has been correlated with human oesophageal cancer in some regions of the world, and some evidence suggests that fumonisins are a risk factor for neural tube defects. A primary goal of the authors’ laboratory is to …

Soil Properties And Macro Cations Status Impacted By Long-Term Applied Poultry Litter, Zhongqi He, Irenus A. Tazisong, Zachary N. Senwo, Donglin Zhang

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

Most ethnic populations worldwide consume poultry products. Whereas poultry litter (PL) is a traditionally inexpensive and effective fertilizer to improve soil quality and agricultural productivity, overapplication to soils has raised concerns because excess nutrients in runoff could accelerate the eutrophication of fresh bodies of water. A long-term field experiment of land application of PL to soils used for pasture growth has been maintained for nearly two decades in the Sand Mountain region of north Alabama, USA. In this work, several soil parameters impacted by the long-term applied litter were characterized. The findings clearly support previous general observations that long-term applied …

Microbial Community Structure Dynamics In Ohio River Sediments During Reductive Dechlorination Of Pcbs, Andres Enrique Nunez

University of Kentucky Doctoral Dissertations

The entire stretch of the Ohio River is under fish consumption advisories due to contamination with polychlorinated biphenyls (PCBs). In this study, natural attenuation and biostimulation of PCBs and microbial communities responsible for PCB transformations were investigated in Ohio River sediments.

Natural attenuation of PCBs was negligible in sediments, which was likely attributed to low temperature conditions during most of the year, as well as low amounts of available nitrogen, phosphorus, and organic carbon. Moreover, surface sediments were relatively oxidized, as indicated by the prevalence of aerobic bacteria such as beta- Proteobacteria, alpha-Proteobacteria, Sphingobacteria, and Nitrospira in 16S rRNA sediment …

Registration Of ‘Darrell’ Wheat, A. M. H. Ibrahim, S. D. Haley, P. S. Baenziger, Y. Jin, M. A. C. Langham, J. Rickertsen, S. Kalsbeck, R. Little, J. Ingemansen, O. K. Chung, B. W. Seabourn, G. H. Bai, Ming-Shun Chen, D. V. Mcvey

Department of Agronomy and Horticulture: Faculty Publications

‘Darrell’ (Reg. No. CV-1024, PI 644224) hard red winter wheat (Triticum aestivum L.) was developed by the South Dakota State University–Agricultural Experiment Station and released in 2006 to seed producers by the South Dakota State University–Agricultural Experiment Station and the University of Nebraska Agricultural Experiment Station. Darrell was selected from the cross 2076-W12-11/‘Karl 92’ (PI 564245)//NE89526. NE89526 is an experimental line from the University of Nebraska with the pedigree ‘Lancota’ (CI 17389) selection/’Siouxland’ (PI 483469)//TX792729. 2076-W12-11 is an unreleased experimental line that originated from a population with an unidentified pedigree. Darrell was selected as an F3:4 line in 1998 …

Comparison Of Nitrogen Fertilization Methods And Rates For Subsurface Drip Irrigated Corn In The Semi-Arid Great Plains, D. D. Tarkalson, J. O. Payero

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

In semi‐arid areas such as western Nebraska, interest in subsurface drip irrigation (SDI) for corn is increasing due to restricted irrigation allocations. However, crop response quantification to nitrogen (N) applications with SDI and the environmental benefits of multiple in‐season (IS) SDI N applications instead of a single early‐season (ES) surface application are lacking. The study was conducted in 2004, 2005, and 2006 at the University of Nebraska‐Lincoln West Central Research and Extension Center in North Platte, Nebraska, comparing two N application methods (IS and ES) and three N rates (128, 186, and 278 kg N ha^-1) using a …

Using The Solvent Retention Capacity Test When Breeding Wheat For Diverse Production Environments, Carl Walker, Kimberly A. Garland-Campbell, Brady Carter, Kimberlee Kidwell

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

The solvent retention capacity (SRC) test is used to predict commercial baking performance of soft wheat (Triticum aestivum L.) by measuring the capacity of flour to retain each of four solvents— water, Na₂CO₃, sucrose, and lactic acid— to assess overall absorption capacity, starch damage, pentosan and gliadin content, and glutenin quality, respectively. Our objectives were to determine sources of variation in the test, repeatability, and optimum scale and resource allocation needed to maximize efficiency. Duplicate SRC tests were conducted for each solvent using two flour sample sizes (5 and 0.2 g) from two field replications …

Winter Cover Crops And Vinegar For Early-Season Weed Control In Sustainable Cotton, P. J. Moran, S. M. Greenberg

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

Weeds may be suppressed by winter cover crops and the use of organic herbicides such as vinegar. Black oat (Avena strigosa) and hairy vetch (Vicia villosa) winter cover crops were planted for 2 years as part of a sustainable production system for cotton in the Lower Rio Grande Valley of Texas, and were till-killed each spring prior to cotton planting. Palmer amaranth (Amaranthus palmeri), common purslane (Portulaca oleracea), and sunflower (Helianthus annuus) were frequently-encountered winter and spring weeds. Both cover crops controlled winter weeds as well as did winter tillage …

A Landscape Perspective In Managing Vegetation For Beneficial Plant-Pestnatural Enemy Interactions: A Foundation For Areawide Pest Management, Michael J. Brewer, Takuji Noma, Norman C. Elliott

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

In the USA, Europe and increasingly in other regions, cropping systems designed for high production output are significant features of the landscape. Deployment of mechanized and high-input cropping systems over the last 50 years has resulted in substantial transformation and fragmentation of major grassland, shrubland and woodland systems throughout the world. These cropping systems are typically less diverse in species composition, structure and ecological functioning than those found in the original plant community (Altieri, 2004). Decreases in plant diversity of agroecosystems (i.e. the crops themselves and surrounding remnants of the original plant system) have negatively affected ecosystem functions (Freemark, 2005). …

Synthesis And Bioassay Of Improved Mosquito Repellents Predicted From Chemical Structure, Alan R. Katritzky, Zuoquan Wang, Svetoslav Slavov, Maia Tsikolia, Dimitar Dobchev, Novruz G. Akhmedov, C. Dennis Hall, Ulrich R. Bernier, Gary G. Clark, Kenneth Linthicum

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

Mosquito repellency data on acylpiperidines derived from the United States Department of Agriculture archives were modeled by using molecular descriptors calculated by CODESSA PRO software. An artificial neural network model was developed for the correlation of these archival results and used to predict the repellent activity of novel compounds of similar structures. A series of 34 promising N-acylpiperidine mosquito repellent candidates (4a–4q’) were synthesized by reactions of acylbenzotriazoles 2a–2p with piperidines 3a–3f. Compounds (4a–4q’) were screened as topically applied mosquito repellents by measuring the duration of repellency after application to cloth patches worn on the arms of human volunteers. Some …

Responsive In-Season Nitrogen Management For Cereals, J.F. Shanahan, N. R. Kitchen, W. R. Raun, James S. Schepers

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

Current nitrogen (N) management strategies for worldwide cereal production systems are characterized by low N use efficiency (NUE), environmental contamination, and considerable ongoing debate regarding what can be done to improve N fertilizer management. Development of innovative strategies that improve NUE and minimize off-field losses is crucial to sustaining cereal-based farming. In this paper, we review the major managerial causes for low NUE, including (1) poor synchrony between fertilizer N and crop demand, (2) uniform field applications to spatially variable landscapes that commonly vary in crop N need, and (3) failure to account for temporally variable influences on crop N …

Asas Centennial Paper: Net Energy Systems For Beef Cattle – Cattles, Application, And Future Models, Calvin Ferrell, J. W. Oltjen

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

Development of nutritional energetics can be traced to the 1400s. Lavoisier established relationships among O₂ use, CO₂ production and heat production in the late 1700s, and the laws of thermodynamics and law of Hess were discovered during the 1840s. Those discoveries established the fundamental bases for nutritional energetics and enabled the fundamental entity ME = retained energy + heat energy to be established. Objectives became: 1) to establish relationships between gas exchange and heat energy, 2) to devise bases for evaluation of foods that could be related to energy expenditures, and 3) to establish causes of energy expenditures. …

A Putative Quantitative Trait Locus On Chromosome 20 Associated With Bovine Pathogenic Disease Incidence, E. Casas, G. Snowder

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

The objective of this study was to detect QTL associated with the incidence of multiple pathogenic diseases in offspring from half-sib bovine families. Four F₁ sires were used to produce offspring: Brahman × Hereford (BH; n = 547), Piedmontese × Angus (PA; n = 209), Brahman × Angus (n = 176), and Belgian Blue × MARC III (n = 246). Treatment records for bovine respiratory disease, infectious keratoconjunctivitis (pinkeye), and infectious pododermatitis (footrot) were available for all of the offspring from birth to slaughter. The incidences of these 3 microbial pathogenic diseases were combined into a single binary trait …

Chapter 18. Daycent Simulated Effects Of Land Use And Climate On County Level N Loss Vectors In The Usa, S. J. Del Grosso, W. J. Parton, D. S. Ojima, C. A. Keough, T. H. Riley, A. R. Mosier

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

We describe the nitrogen (N) gas (NH₃, NO_x, N₂O, N₂) emission and NO₃ leaching submodels used in the DAYCENT ecosystem model and demonstrate the ability of DAYCENT to simulate observed N₂O emission and NO₃ leaching rates for various sites representing different climate regimes, soil types, and land uses. DAYCENT simulated seven major crops, grazing lands, and potential native vegetation at the county level for the United States. At the national scale, NO₃ leaching was the major loss vector, accounting for 86%, 66%, and 56% of total N …

Chapter 15. Proven Practices And Innovative Technologies For On-Farm Crop Nitrogen Management, N. R. Kitchen, K. W. T. Goulding, J.F. Shanahan

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

Nitrogen (N) from soil, fertilizer, and manure sources is generally inefficiently used (30-60%) in most crop production systems. As a consequence, unused inorganic N can move off crop fields and contaminate surface and groundwater resources. Local and national governments have responded with guidelines, standards, regulations, and in some cases fines when off-field losses of N have not been reduced. Along with these environmental pressures, soaring energy costs have resulted in commensurate increased costs for N fertilizers. These factors are real for crop producers and are compelling them to scrutinize their crop N management more closely than in previous decades. Numerous …

Chapter 4. Relationship Of Environmental Nitrogen Metabolism To Human Health, J. R. Follett, R. F. Follett

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

The need for humans to produce and consume food and other agricultural products is increasing. This need is directly related to increasing world populations, demands for goods and services, and expectations. Nitrogen (N) is contained in all of the amino acids and proteins in the foods consumed by humans. The use of N to produce food and other products is generally increasing as human needs increase. Proteins are an essential component of the human diet because, unlike plants, humans are unable to utilize more simple forms of N and rely on food sources for protein which can then be digested …

Effect Of Sample Processing Procedures On Measurement Of Starch In Corn Silage And Corn Grain, M. B. Hall, D. R. Mertens

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

Methods for processing feedstuffs before analysis can affect analytical results. Effects of drying temperature (corn silage), preservation method (corn grain), and grinding method (corn silage and grain) on starch analysis values were evaluated. Corn silage samples dried at 55 or 105°C and grain samples dried at 55°C were ground to pass the 1-mm screen of an abrasion mill or cutting mill and analyzed for free glucose and starch corrected for free glucose. Starch analyses were performed in triplicate to assess the effect of treatment on precision of starch determination. Drying at 105°C decreased free glucose and tended to decrease starch …

Using The Solvent Retention Capacity Test When Breeding Wheat For Diverse Production Environments, Carl Walker, Kimberly A. Garland-Campbell, Brady Carter, Kimberlee Kidwell

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

The solvent retention capacity (SRC) test is used to predict commercial baking performance of soft wheat (Triticum aestivum L.) by measuring the capacity of fl our to retain each of four solvents— water, Na₂CO₃, sucrose, and lactic acid— to assess overall absorption capacity, starch damage, pentosan and gliadin content, and glutenin quality, respectively. Our objectives were to determine sources of variation in the test, repeatability, and optimum scale and resource allocation needed to maximize efficiency. Duplicate SRC tests were conducted for each solvent using two flour sample sizes (5 and 0.2 g) from two field …

Initial Response Of Evapotranspiration From Tallgrass Prairie Vegetation To Co2 At Subambient To Elevated Concentrations, H. W. Polley, H. B. Johnson, P. A. Fay, J. Sanabria

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

A series of weighing lysimeters in which tallgrass prairie species had been planted were exposed to a subambient to elevated gradient in CO₂ in a field chamber. Lysimeters with intact monoliths of three soil types were represented along the CO₂ gradient. We used regression analysis to determine how CO₂ effects on evapotranspiration per unit of soil surface area (ET_soil) and per unit of leaf area (ET_la) depended on variation in leaf area index (LAI) and diurnal changes in environmental variables during the initial 6 weeks of CO₂ treatment.

Hydraulic Core Extraction: Cutting Device For Soil–Root Studies, T. S. Kornecki, S. A. Prior, G. B. Runion, H. H. Rogers, D. C. Erbach

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

A critical objective of belowground research is to collect and process representative soil samples. Mechanical devices have been developed to quickly take soil cores in the field; however, techniques to rapidly process large-diameter soil cores are lacking. Our objective was to design and construct a soil extraction–cutting system that could effectively reduce processing time. Soil cores were extracted from large diameter steel core tubes using a custom hydraulic cylinder device that vertically pushes the soil core to a desired depth increment before cutting in a horizontal direction with another hydraulically driven device. As many as eight large cores per hour …

Growth And Feed Efficiency Of Juvenile Channel Catfish Reared At Different Water Temperatures And Fed Diets Containing Various Levels Of Fish Meal, Menghe H. Li, Edwin H. Robinson, Brian C. Peterson, Terry D. Bates

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

Channel catfish Ictalurus punctatus do not feed well at low temperatures. It is generally thought that a diet containing fish meal enhances feed palatability at low temperatures since fish meal is highly palatable to fish. There is a lack of information on the effects of fish meal levels on the growth performance of channel catfish reared at low temperatures. Therefore, a study was conducted in a recirculating system to examine the effects of fish meal levels on the feed consumption, weight gain, and feed efficiency of juvenile channel catfish reared at various temperatures. Fish with an initial weight of 9.6 …

Water And Bromide Recovery In Wick And Pan Lysimeters Under Conventional And Zero Tillage, John P. Schmidt, Henry Lin

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

Quantifying in situ solute transport through soils and the landscape has been widely acknowledged as important and yet challenging. The objective of this study was to evaluate water and bromide movement in no-tilled (NT) and conventionally tilled (CT) corn using two different types of in situ lysimeters—pan and capillary wick— for single rainfall events. Four zero-tension pan and four capillary-wick lysimeters were installed 1.2 m deep on opposite sides of four soil pits. Two were under NT corn, and two were under CT corn. Bromide (Br) was either surface applied or applied with an initial 25 to 27 mm of …

Nationally Coordinated Evaluation Of Soil Nitrogen Mineralization Rate Using A Standardized Aerobic Incubation Protocol, T. S. Griffin, C. W. Honeycutt, S. L. Albrecht, K. R. Sistani, H. A. Torbert, B. J. Wienhold, B. L. Woodbury, R. K. Hubbard, J. M. Powell

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

Aerobic incubation methods have been widely used to assess soil nitrogen (N) mineralization, but standardized protocols are lacking. A single silt loam soil (Catlin silt loam; fine-silty, mixed, superactive, mesic, Oxyaquic Arguidoll) was subjected to aerobic incubation at six USDA-ARS locations using a standardized protocol. Incubations were conducted at multiple temperatures, which were combined based on degree days (DD). Soil water was maintained at 60% waterfilled pore space (WFPS; constant) or allowed to fluctuate between 60 and 30% WFPS (cycle). Soil subsamples were removed periodically and extracted in 2 M potassium chloride (KCl); nitrate (NO₃) and ammonium (NH …

Areawide Suppression Of Fire Ants, M. D. Aubuchon, R. K. Vander Meer

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

The imported fire ants, Solenopsis invicta and S. richteri, were inadvertently introduced into the USA in the early 1900s and currently inhabit over 129 million ha in Puerto Rico and 12 southern states, from Texas to Virginia (Callcott and Collins, 1996; USDA-APHIS map). Imported fire ants have also become established in isolated sites in California, Arizona, New Mexico and Maryland. Strict quarantine procedures have limited the spread of this pest (Lockley and Collins, 1990), but eventually populations will expand westward in increasing numbers in New Mexico, Arizona and California. They will also move upward along the Pacific coast, southward …

The Hawaii Fruit Fly Areawide Pest Management Programme, Roger I. Vargas, Ronald F. L. Mau, Eric B. Jang, Robert M. Faust, Lyle Wong

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

Fruit flies (Diptera: Tephritidae) are among the most economically important pests attacking soft fruits worldwide (White and Elson-Harris, 1992). Four invasive species Mediterranean fruit fly or medfly (Ceratitis capitata), melon fly (Bactrocera cucurbitae), oriental fruit fly (Bactrocera dorsalis) and the so-called Malaysian fruit fly or solanaceous fruit fly (Bactrocera latifrons) - have been devastating to Hawaiian agriculture for over 100 years by infesting more than 400 different host plants. These fruit flies:

• Jeopardize development of a diversified tropical fruit and vegetable industry.

• Require that commercial fruits undergo quarantine treatment prior …

Short Communication- An Update On The Diversity Of Wolbachia In Spalangia Spp. (Hymenoptera: Pteromalidae), K.D. Floate, P.C. Coghlin, D. B. Taylor

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

Results from 13 additional host populations improves resolution on the diversity of Wolbachia bacteria in Spalangia spp. (Hymenoptera: Pteromalidae). These bacteria are of interest because they can profoundly affect their host’s reproduction. Manipulating Wolbachia infections may provide a method to improve the efficacy of biocontrol agents including Spalangia spp.

Parasitoid wasps (Pteromalidae: Hymenoptera) are of interest as biocontrol agents for pest flies (Diptera: Muscidae) of livestock confinements; e.g. dairies, cattle feedlots, poultry houses, swine barns. Many of these wasps are infected with Wolbachia bacteria that can profoundly affect their host’s reproduction. Wolbachia induce parthenogenesis in Muscidifurax uniraptor Kogan & Legner …

Aged Switchgrass Seed Lot's Response To Dormancy-Breaking Chemicals, Gautam Sarath, Robert B. Mitchell

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

Aged switchgrass seed lots can display various levels of dormancy. Under-standing the causes for this dormancy will provide better insight into seed physiology, and potentially lead to treatments that reduce variability in seed germination assays. The effects of sodium nitroprusside, potassium ferro-cyanide and hydrogen peroxide on the germination of eight aged switch-grass (Panicum virgatum L.) seed lots, seven of which were produced in the same year at a single experiment station, were examined. Seed germination demonstrated a significant seed lots × days and treatments × days effect. However, responses of individual seed lots to specific chemicals varied considerably. Genetically …