Digital Commons Network^™

Corn Rootworm Areawide Pest Management In The Midwestern Usa, Laurence D. Chandler, James R. Coppedge, C. Richard Edwards, Jon J. Tollefson, Gerald R. Wilde, Robert M. Faust

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

For many maize (Zea mays) producers across the Midwestern USA, as well as in parts of the northern and southern plains, the corn rootworm complex (Diabrotica spp.; Coleoptera: Chrysomelidae) has represented one of the greatest challenges to efficient, quality maize-grain production over the past 50-60 years. Three species of corn rootworm are particularly troublesome: the western corn rootworm, Diabrotica virgifera virgifera, the northern corn rootworm, D. barberi and the Mexican corn rootworm, D. virgifera zeae; all have consistently been important economic pests of maize (Metcalf, 1986b). Prior to the introduction of transgenic maize varieties designed …

Central And Peripheral Administration Of Kisspeptin Activates Gonadotropin But Not Somatotropin Secretion In Prepubertal Gilts, Clay A. Lents, Neely L. Heidorn, C. Richard Barb, J. Joe Ford

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

It is well established that kisspeptin signaling is necessary for the onset of puberty in laboratory animals. However, the role that kisspeptin may have in regulating puberty in large domestic animals is unknown.We tested the hypothesis that either central or peripheral infusion of kisspeptin would stimulate gonadotropin and GH secretion in prepubertal gilts. In experiment 1, prepubertal gilts were fitted with i.c.v. cannula and indwelling jugular catheters. Animals were randomly assigned to receive 0, 10, or 100 μg kisspeptin in saline. In experiment 2, prepubertal gilts, fitted with indwelling jugular catheters, randomly received 0, 1, 2.5, or 5 mg kisspeptin …

Improvement Of Perennial Forage Species As Feedstock For Bioenergy, William Anderson, Michael Casler, Brian S. Baldwin

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

Both native and non-native forage species other than switchgrass are less commonly considered as potential lignocellulosic feedstocks for bioenergy in the United States. These species hold potential as bioenergy feedstocks because of the experience and infrastructure that is already in place for management and harvest, and in certain areas of the country they have greater yield potential than switchgrass or other feedstocks. The forage grasses consist of temperate cool-season (most commonly C3) grasses as well as tropical or sub-tropical warm-season (C4) grasses. Some legume species may also play a significant role in supplying useful bioenergy feedstocks. Most have been researched …

The Artiodactyl Apobec3 Innate Immune Repertoire Shows Evidence For A Multi-Functional Domain Organization That Existed In The Ancestor Of Placental Mammals, Rebecca Larue, Stefán Jónsson, Kevin Silverstein, Mathieu Lajoie, Denis Bertrand, Nadia El-Mabrouk, Isidro Hötzel, Valgerdur Andrésdóttir, Timothy Smith, Reuben Harris

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

Background: APOBEC3 (A3) proteins deaminate DNA cytosines and block the replication of retroviruses and retrotransposons. Each A3 gene encodes a protein with one or two conserved zinccoordinating
motifs (Z1, Z2 or Z3). The presence of one A3 gene in mice (Z2–Z3) and seven in humans, A3A-H (Z1a, Z2a-Z1b, Z2b, Z2c-Z2d, Z2e-Z2f, Z2g-Z1c, Z3), suggests extraordinary evolutionary flexibility. To gain insights into the mechanism and timing of A3 gene expansion and into the functional modularity of these genes, we analyzed the genomic sequences, expressed cDNAs and activities of the full A3 repertoire of three artiodactyl lineages: sheep, cattle and pigs.
Results: …

Susceptibility Of Eggs And Adult Fecundity Of The Lesser Grain Borer, Rhyzopertha Dominica, Exposed To Methoprene, Y. Chanbang, F. H. Arthur, G. E. Wilde, J. E. Throne, Bh. Subramanyam

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

A series of tests were conducted to determine the susceptibility of eggs and neonates of the lesser grain borer Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae = Bostrychidae), exposed to the insect growth regulator, methoprene, on filter paper and on rough rice. In the first test, the hatch rate of eggs exposed on filter paper treated with methoprene at the label rate of 0.003 mg [AI] /cm² when used as a surface treatment in structures was 52.0 ± 7.3% compared to 93.0 ± 3.3% on untreated controls. In the second test, eggs were exposed to a dose-response series of 0.00003 to …

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 …

Differential Effects Of Understory And Overstory Gaps On Tree Regeneration, Brian Beckage, Brian D. Kloeppel, J. Alan Yeakley, Sharon F. Taylor, David C. Coleman

Environmental Science and Management Faculty Publications and Presentations

Gaps in the forest canopy can increase the diversity of tree regeneration. Understory shrubs also compete with tree seedlings for limited resources and may depress tree recruitment. We compared effects of shrub removal and canopy windthrow gaps on seedling recruitment and understory resource levels. Shrub removal, with the canopy left intact, was associated with increased levels of understory light and soil moisture and coincided with increased species richness and diversity of tree regeneration compared to both control plots and canopy gaps. Canopy windthrow gaps, however, resulted in a more than 500 fold increase in soil nitrate concentrations, and seedling growth …

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 …

A Dgge-Cloning Method To Characterize Arbuscular Mycorrhizal Community Structure In Soil, Zhanbei Liang, Rhae A. Drijber, Donald J. Lee, Ismail M. Dwiekat, Steven D. Harris, David A. Wedin

Department of Plant Pathology: Faculty Publications

Although arbuscular mycorrhizal fungi (AMF) are crucial for ecosystem functioning, characterizing AMF community structure in soil is challenging. In this study, nested polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) were combined with cloning of fungal 18S ribosomal gene fragments for the rapid comparison of AMF community structure in soil. Reference AMF isolates, representing four major genera of AMF, were used to develop the method. Sequential amplification of 18S rDNA fragments by nested PCR using primer pairs AM1-NS31 and Glo1-NS31GC followed by DGGE analysis yielded a high-resolution band profile. In parallel, 18S rDNA fragment clone libraries were constructed …

Virulence Diversity Of The Common Bean Rust Pathogen Within And Among Individual Bean Fields And Development Of Sampling Strategies, C. Jochua, M. I. V. Amane, J. R. Steadman, X. Xue, K. M. Eskidge

Department of Plant Pathology: Faculty Publications

There is a dearth of information on pathogen variation within an individual field. In this study, virulence diversity of Uromyces appendiculatus, cause of bean rust, within individual fields was investigated. From six bean fields in the United States, Honduras, Dominican Republic, and South Africa, 380 U. appendiculatus isolates were differentiated into 65 virulence phenotypes on bean lines containing Andean- and Middle American-derived rust resistance genes. Race variation among bean rust isolates from different geographic regions was found, and virulence phenotypes found in fields from tropical and subtropical regions were more virulent and diverse than those found in fields from …

Branching Of Fungal Hyphae: Regulation, Mechanisms And Comparison With Other Branching Systems, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The ability of rapidly growing hyphae to generate new polarity axes that result in the formation of a branch represents one of the most important yet least understood aspects of fungal cell biology. Branching is central to the development of mycelial colonies and also appears to play a key role in fungal interactions with other organisms. This review presents a description of the two major patterns of hyphal branching, apical and lateral, and highlights the roles of internal and external factors in the induction of branch formation. In addition, potential mechanisms underlying branch site selection are outlined, and the possible …

First Report Of Annual Bluegrass Weevil, Listronotus Maculicollis, Damage In Ohio, John L. Koenig, David J. Shetlar, Joseph W. Rimelspach, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Annual bluegrass weevil [Listronotus maculicollis (Kirby) (1)] larvae, pupae, and adults were recovered and identified in a sample received by the C. Wayne Ellett Plant and Pest Diagnostic Clinic (CWEPPDC) at Ohio State University on 19 June 2007. Damage to the approaches and collars of four golf course putting greens was detected by the superintendent of Stonewater Golf Club, Highland Heights, OH (a suburb of Cleveland) during the week of 11 June 2007. The superintendent suspected damage from the larvae of the black turfgrass ataenius, Ataenius spretulus (1). Insecticide applications applied to suppress black turfgrass ataenius did not provide …

Rapid Development Of Fungicide Resistance By Sclerotinia Homoeocarpa On Turfgrass, Young-Ki Jo, Seog Won Chang, Michael J. Boehm, Geunhwa Jung

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa, is the most prevalent and economically important turfgrass disease in North America. Increasing levels of fungicide resistance, coupled with tightening environmental scrutiny of existing fungicides, has left fewer options for managing dollar spot. More knowledge about S. homoeocarpa populations is needed to improve dollar spot management strategies, especially with respect to minimizing the development of fungicide resistance. Population diversity of S. homoeocarpa was examined using inter-simple sequence repeat markers and vegetative compatibility assays. Two subgroups were found in S. homoeocarpa field populations on both fairway and putting green turfgrass at a research field …

Inoculation Strategies To Assess Biological Interactions Between Fusarium And Alternaria Species Infecting Sorghum, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

New cultivars of sorghum are being developed for increased food use, as livestock feed, and for the bioenergy industry by manipulation of secondary metabolic pathways through breeding. Previous work has suggested that such modifications may have an impact on cultivar response to fungal pathogens. We investigated four inoculation strategies that may be used in studies involving pathogens of sorghum. Plants of elite sorghum genotypes ‘Wheatland’ and RTx430, commonly used in breeding programs, were inoculated with isolates of Alternaria alternata, Fusarium equiseti, Fusarium proliferatum, Fusarium solani, Fusarium thapsinum, and Fusarium verticillioides recovered from field-grown sorghum. Wound inoculation of the peduncles …

Cloning And Characterization Of A Caesalpinoid (Chamaecrista Fasciculata) Hemoglobin: The Structural Transition From A Nonsymbiotic Hemoglobin To A Leghemoglobin, Sabarinathan K. Gopalasubramaniam, Frank A. Kovacs, Fernando Violante-Mota, Paul Twigg, Raul Arredondo-Peter, Gautam Sarath

Department of Agronomy and Horticulture: Faculty Publications

Nonsymbiotic hemoglobins (nsHbs) and leghemoglobins (Lbs) are plant proteins that can reversibly bind O₂ and other ligands. The nsHbs are hexacoordinate and appear to modulate cellular concentrations of NO and maintain energy levels under hypoxic conditions. The Lbs are pentacoordinate and facilitate the diffusion of O₂ to symbiotic bacteroids within legume root nodules. Multiple lines of evidence suggest that all plant Hbs evolved from a common ancestor and that Lbs originated from nsHbs. However, little is known about the structural intermediates that occurred during the evolution of pentacoordinate Lbs from hexacoordinate nsHbs. We have cloned and characterized a …

Effect Of Sorghum Seedlings, And Previous Crop, On Soil Fluorescent Pseudomonas Spp., Deanna L. Funnell-Harris, Jeffrey Pedersen, David B. Marx

Department of Agronomy and Horticulture: Faculty Publications

Hypotheses in which sorghum seedlings [Sorghum bicolor (L.) Moench] of different genotypes will differentially modify soil microorganisms and will affect subsequent planting of wheat (Triticum aestivum L.) seedlings, were tested. Wheat cultivar Lewjain, and sorghum genotypes Redlan and RTx433, were planted into soils previously planted with wheat or sorghum in growth chamber experiments. Total culturable fungi and oomycetes, and fluorescent Pseudomonas spp. numbers (cfu) were determined. Pseudomonads were screened for hydrogen cyanide (HCN) production, for the presence of the phlD gene for 2,4-diacetylphloroglucinol production (Phl) and for a region of the operon involved in phenazine-1-carboxylic acid (PCA) production. …

Importance And Effect Of Nitrogen On Crop Quality And Health, Jürg Blumenthal, David D. Baltensperger, Kenneth G. Cassman, Stephen Mason, Alexander Pavlista

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen (N) is often the most limiting factor in crop production. Hence, application of fertilizer nitrogen results in higher biomass yields and protein yield and concentration in plant tissue is commonly increased. Nitrogen often affects amino acid composition of protein and in turn its nutritional quality. In cereals, abundant supply of nitrogen decreases the relative proportion of lysine and threonine, thus, reducing the biological value of the protein. Increasing nitrogen supply generally improves kernel integrity and strength, resulting in better milling properties of the grain. In oil seed crops, protein levels are increased upon nitrogen fertilization, whereas oil concentration is …

Harvester Ant Nests Improve Recovery Performance Of Drought Impacted Vegetation In Grazing Regimes Of Semiarid Savanna, Texas, Nancy Nicolai, Fred Smeins, Jerry Cook

Department of Agronomy and Horticulture: Faculty Publications

Vegetation composition is often dictated by grazing intensity in semiarid savannas; recovery following drought may depend on pre drought species composition. Nests of the red harvester ant, Pogonomyrmex barbatus, affect the dynamics, composition and recovery of post drought communities due to their larger size, greater seed production and higher perennial grass richness. We hypothesized that vegetation at ant nests would survive drought and recover faster than vegetation in the surrounding grasslands, but that individual and population recovery would depend on plant species composition, which, in turn, would be influenced by grazing intensity. We assessed nest influence on density, cover, …

Modeling Responses Of Dryland Spring Triticale, Proso Millet And Foxtail Millet To Initial Soil Water In The High Plains, S. A. Saseendran, D. C. Nielsen, Drew J. Lyon, L. Ma, D. D. Baltensperger, G. Hoogenboom, L.R. Ahuja

Department of Agronomy and Horticulture: Faculty Publications

Dryland farming strategies in the High Plains must make efficient use of limited and variable precipitation and stored water in the soil profile for stable and sustainable farm productivity. Current research efforts focus on replacing summer fallow in the region with more profitable and environmentally sustainable spring and summer crops. In the absence of reliable precipitation forecasts for the crop growing season, farmers rely mainly upon knowledge of plant available water (PAW) in the soil profile at planting for making crop choice decisions. To develop a decision support strategy for crop selection based on initial PAW, experiments were conducted with …

Characterization Of The Folate Salvage Enzyme P-Aminobenzoylglutamate Hydrolase In Plants, Gale G. Bozzo, Gilles J. C. Basset, Valeria Naponelli, Alexandre Noiriel, Jesse F. Gregory Iii, Andrew D. Hanson

Department of Agronomy and Horticulture: Faculty Publications

Folates break down in vivo to give pterin and p-aminobenzoylglutamate (pABAGlu) fragments, the latter usually having a polyglutamyl tail. Pilot studies have shown that plants can hydrolyze pABAGlu and its polyglutamates to p-aminobenzoate, a folate biosynthesis precursor. The enzymatic basis of this hydrolysis was further investigated. pABAGlu hydrolase activity was found in all species and organs tested; activity levels implied that the proteins responsible are very rare. The activity was located in cytosol/vacuole and mitochondrial fractions of pea (Pisum sativum L.) leaves, and column chromatography of the activity from Arabidopsis tissues indicated at …

Detection And Quantification Of Vitamin K1 Quinol In Leaf Tissues, Chloë Van Oostende, Joshua R. Widhalm, Gilles J.C. Basset

Department of Agronomy and Horticulture: Faculty Publications

Phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone; vitamin K₁) is vital to plants. It is responsible for the oneelectron transfer at the A1 site of photosystem I, a process that involves turnover between the quinone and semi-quinone forms of phylloquinone. Using HPLC coupled with fluorometric detection to analyze Arabidopsis leaf extracts, we detected a third redox form of phylloquinone corresponding to its fully reduced – quinol–naphthoquinone ring (PhQH₂). A method was developed to quantify PhQH₂ and its corresponding oxidized quinone (PhQ) counterpart in a single HPLC run. PhQH₂ was found in leaves of all dicotyledonous and monocotyledonous species tested, …

Whole-Plant Mineral Partitioning Throughout The Life Cycle In Arabidopsis Thaliana Ecotypes Columbia, Landsberg Erecta, Cape Verde Islands, And The Mutant Line Ysl1ysl3, Brian M. Waters, Michael A. Grusak

Department of Agronomy and Horticulture: Faculty Publications

Minimal information exists on whole-plant dynamics of mineral flow through Arabidopsis thaliana or on the source tissues responsible for mineral export to developing seeds. Understanding these phenomena in a model plant could help in the development of nutritionally enhanced crop cultivars. A whole-plant partitioning study, using sequential harvests, was conducted to characterize growth and mineral concentrations and contents of rosettes, cauline leaves, stems, immature fruit, mature fruit hulls, and seeds of three WT lines (Col-0, Ler, and Cvi) and one mutant line (Col-0::ysl1ysl3). Shoot mineral content increased throughout the life cycle for all minerals, although tissue-specific …

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 …

Geographic Patterns Of At-Risk Species, Curtis H. Flather, Michael S. Knowles, Jason Mcnees

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

This technical document supports the Forest Service’s requirement to assess the status of renewable natural resources as mandated by the Forest and Rangeland Renewable Resources Planning Act of 1974. It updates past reports on the trends and geographic patterns of species formally listed as threatened or endangered under the Endangered Species Act of 1973. We compare the geographic occupancy of threatened and endangered species at the county-level against the geographic occupancy of a broader set of species thought to be at risk of extinction. This is done to determine if new areas where species rarity may be concentrated emerge. Here …

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 …

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. …