Agricultural Science Commons^™

Saving The Sagebrush Sea: An Ecosystem Conservation Plan For Big Sagebrush Plant Communities, Kirk W. Davies, Chad S. Boyd, Jeffrey L. Beck, Jon D. Bates, Tony J. Svejcar, Michael A. Gregg

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

Vegetation change and anthropogenic development are altering ecosystems and decreasing biodiversity. Successful management of ecosystems threatened by multiple stressors requires development of ecosystem conservation plans rather than single species plans. We selected the big sagebrush (Artemisia tridentata Nutt.) ecosystem to demonstrate this approach. The area occupied by the sagebrush ecosystem is declining and becoming increasingly fragmented at an alarming rate because of conifer encroachment, exotic annual grass invasion, and anthropogenic development. This is causing rangewide declines and localized extirpations of sagebrush associated fauna and flora. To develop an ecosystem conservation plan, a synthesis of existing knowledge is …

Effects Of Transmission Gear Selection On Tractor Performance And Fuel Costs During Deep Tillage Operations, C.M. Kichler, J.P. Fulton, R.L. Raper, T.P. Mcdonald, W.C. Zech

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

Deep tillage operations required to alleviate soil compaction common in the Southeastern US remain energy intensive and expensive. Equipment performance and in-field efficiency are two variables that can be improved to minimize fuel consumption and ultimately reduce input costs for crop production. The objective of this study was to investigate the effects of transmission gear selection on fuel costs, draft, and other equipment performance variables using two deep tillage implements. Three different transmission gears were selected which represented slow, normal, and fast operating speeds for two typical in-row, integral subsoilers (KMC generation I rip-strip and Bigham Brothers Paratill^TM). …

Differentially Expressed Genes In Populus Simonii×Populus Nigra In Response To Nacl Stress Using Cdna-Aflp, Lei Wang, Boru Zhou, Lili Wu, Baozhu Guo, Tingbo Jiang

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

Salinity is an important environmental factor limiting growth and productivity of plants, and affects almost every aspect of the plant physiology and biochemistry. The objective of this study was to apply cDNA-AFLP and to identify differentially expressed genes in response to NaCl stress vs. no-stress in Populus simonii × Populus nigra in order to develop genetic resources for genetic improvement. Selective amplification with 64 primer combinations allowed the visualization of 4407 transcript-derived fragments (TDFs), and 2027 were differentially expressed. Overall, 107 TDFs were re-sequenced successfully, and 86 unique sequences were identified in 10 functional categories based on their putative functions. …

Methodologies For Simulating Impacts Of Climate Change On Crop Production, Jeffrey W. White, Gerrit Hoogenboom, Bruce A. Kimball, Gerard W. Wall

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

Ecophysiological models are widely used to forecast potential impacts of climate change on future agricultural productivity and to examine options for adaptation by local stakeholders and policy makers. However, protocols followed in such assessments vary to such an extent that they constrain cross-study syntheses and increase the potential for bias in projected impacts. We reviewed 221 peer-reviewed papers that used crop simulation models to examine diverse aspects of how climate change might affect agricultural systems. Six subject areas were examined: target crops and regions; the crop model(s) used and their characteristics; sources and application of data on [CO₂] …

Evaluation Of Waxy Grain Sorghum For Ethanol Production, Shuping Yan, Xiaorong Wu, Scott R. Bean, Jeffery F. Pedersen, Tesfaye Tesso, Yuanhong Chen, Donghai Wang

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

The objective of this research was to investigate the fermentation performance of waxy grain sorghum for ethanol production. Twenty-five waxy grain sorghum varieties were evaluated with a laboratory dry-grind procedure. Total starch and amylose contents were measured following colorimetric procedures. Total starch and amylose contents ranged from 65.4 to 76.3% and from 5.5 to 7.3%, respectively. Fermentation efficiencies were in the range of 86.0-92.2%, corresponding to ethanol yields of 2.61-3.03 gallons/bushel. The advantages of using waxy sorghums for ethanol production include easier gelatinization and low viscosity during liquefaction, higher starch and protein digestibility, higher free amino nitrogen (FAN) content, and …

Anointing Chemicals And Hematophagous Arthropods: Responses By Ticks And Mosquitoes To Citrus (Rutaceae) Peel Exudates And Monoterpene Components, Paul J. Weldon, John F. Carroll, Matthew H. Kramer, Robert H. Bedoukian, Russell E. Coleman, Ulrich R. Bernier

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

Some birds and mammals roll on or wipe themselves with the fruits or leaves of Citrus spp. or other Rutaceae. These anointing behaviors, as with anointing in general, are thought to function in the topical acquisition of chemicals that deter consumers, including hematophagous arthropods. We measured avoidance and other responses by nymphal lone star ticks (Amblyomma americanum) and adult female yellow fever mosquitoes (Aedes aegypti) to lemon peel exudate and to 24 volatile monoterpenes (racemates and isomers), including hydrocarbons, alcohols, aldehydes, acetates, ketones, and oxides, present in citrus fruits and leaves in order to examine their …

Reflectance-Based Nitrogen Fertilizer Management For Irrigated Cotton, Kevin F. Bronson

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

Water and nitrogen are the first and second constraints to cotton production in the arid southwestern U.S, respectively (Morrow and Krieg, 1990). Subsurface drip irrigation (SDI) area in cottonland is currently estimated at 300,000 ac, and is growing (Jim Bordovsky, personal communication). Efficiency of water application to cotton in SDI systems is about 90% (Bordovsky and Lyle, 1998). However, N management research for cotton in SDI has not kept up with the water management research. Improving N fertilizer use efficiency would allow lower rates of N fertilizer to be used by producers without hurting lint yields. The reduced costs of …

Nitrous Oxide Emissions From Several Nitrogen Sources Applied To A Strip-Tilled Corn Field, Ardell Halvorson, Stephen J. Del Grosso, Claudia Pozzi Jantalia

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

We evaluated the effects of nitrogen (N) source on nitrous oxide (N₂O) emissions from a clay loam soil that was in strip-tilled (ST), irrigated continuous corn production in 2010 near Fort Collins, CO. Emissions were monitored from six different inorganic N fertilizer sources (urea, ESN¹, SuperU, UAN, UAN+AgrotainPlus, UAN+Nfusion). Each N source was applied at a rate of 202 kg N/ha, surface band applied near the corn row and watered into the soil the day after application including a subsurface band application of ESN (ESNssb). A check treatment (no N applied since 2000) located in separate …

The Acute Toxicity Of The Death Camas (Zigadenus Species) Alkaloid Zygacine In Mice, Including The Effect Of The Methyllycaconitine Coadministration On Zygacine Toxicity, K. D. Welch, K. E. Panter, D. R. Gardner, B. L. Stegelmeier, B. T. Green, J. A. Pfister, D. Cook

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

Death camas (Zigadenus spp.) is a common poisonous plant on foothill rangelands in western North America. The steroidal alkaloid zygacine is believed to be the primary toxic component in death camas. Poisonings on rangelands generally occur in the spring when death camas is abundant, whereas other more desirable forage species are limited in availability. In most cases where livestock are poisoned by plants in a range setting, there is more than one potential poisonous plant in that area. One common poisonous plant that is often found growing simultaneously in the same area as death camas is low larkspur ( …

Dry Matter Production And Leaf Elemental Concentrations Of Rambutan Grown On An Acid Ultisol, Ricardo Goenaga

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

Little is known about the adaptability of rambutan (Nephelium lappaceum) to highly acidic soils rich in aluminum (Al). A 2-yr field study was conducted to determine the effects of various levels of soil Al on dry matter production, plant growth, and nutrient concentration in the leaves of four cultivars of rambutan. Cultivars and the cultivar x year interaction were not statistically significant for most variables measured in the study. Total, leaf, petiole, stem and root dry weights significantly increased at soil Al concentrations ranging from 0.67 cmol kg⁻¹ to 11.0 cmol kg⁻¹. At this range …

Discriminating Microsatellites From Macrophomina Phaseolina And Their Potential Association To Biological Functions, R. S. Arias, J. D. Ray, A. Mengistu, B. E. Scheffler

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

One hundred and eighty-two microsatellites or simple-sequence-repeat (SSR) markers for Macrophomina phaseolina were developed. These were tested on 24 isolates of M. phaseolina obtained from seven plant species, and the genetic variation of isolates was studied in relation to potential biological processes that could be affected in this fungus. A total of 120 SSR markers were polymorphic, amplifying >90% of the 24 isolates tested. Thirty percent of the markers showed multiple alleles on individual samples. A large number of markers showed unique alleles in isolates collected from pumpkin and snap bean. DNA sequences corresponding to 43 markers had significant hits …

Field-Scale Soil Property Changes Under Switchgrass Managed For Bioenergy, Marty R. Schmer, M. A. Liebig, K. P. Vogel, Robert B. Mitchell

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

The capacity of perennial grasses to affect change in soil properties is well documented but information on switchgrass (Panicum virgatum L.) managed for bioenergy is limited. An on-farm study (10 fields) in North Dakota, South Dakota, and Nebraska was sampled before switchgrass establishment and after 5 years to determine changes in soil bulk density (SBD), pH, soil phosphorus (P), and equivalent mass soil organic carbon (SOC). Changes in SBD were largely constrained to near-surface depths (0–0.05 m). SBD increased (0–0.05 m) at the Nebraska locations (mean=0.16 Mgm^-3), while most South Dakota and North Dakota locations showed declines …

Community Structures Of Fecal Bacteria In Cattle From Different Animal Feeding Operations, Orin C. Shanks, Catherine A. Kelty, Shawn Archibeque, Michael Jenkins, Ryan Newton, Sandra L. Mclellan, Susan M. Huse, Mitchell L. Sogin

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

The fecal microbiome of cattle plays a critical role not only in animal health and productivity but also in food safety, pathogen shedding, and the performance of fecal pollution detection methods. Unfortunately, most published molecular surveys fail to provide adequate detail about variability in the community structures of fecal bacteria within and across cattle populations. Using massively parallel pyrosequencing of a hypervariable region of the rRNA coding region, we profiled the fecal microbial communities of cattle from six different feeding operations where cattle were subjected to consistent management practices for a minimum of 90 days. We obtained a total of …

Use Of Gis-Based Site-Specific Nitrogen Management For Improving Energy Efficiency, Kevin F. Bronson, Peter C. Scharf, Newell R. Kitchen

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

To our knowledge, geographical information system (GIS)-based site-specific nitrogen management (SSNM) techniques have not been used to assess agricultural energy costs and efficiency. This chapter uses SSNM case studies for corn (Zea mays L.) grown in Missouri and cotton (Gossypium hirsutum L.) grown in Texas. In five case studies, the impact of SSNM will be compared with blanket N fertilizer recommendations. The five case studies are investigating (I) the impact N on energy produced in cotton production, (2) the impact of variable-rate N for cotton production based on soil nitrate and crop reflectance, (3) the feasibility of variable-rate …

Twentieth-Century Trends In Essential Fatty Acid Intakes And The Predicted Omega-3 Index: Evidence Versus Estimates, William S. Harris, David M. Klurfeld

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

Although the health benefits of omega-3 (n–3) fatty acids are widely appreciated, those of the omega-6 (n–6) fatty acids have become somewhat controversial in recent years, with some viewing them as harmful at current intakes (1, 2) and others (3) [including the American Heart Association (4)] supporting the status quo. Understanding the relations between intakes of these essential fatty acids and disease prevalence over time could inform the debate. To that end, this issue of the Journal contains a report by Blasbalg et al (5) that attempts to reconstruct those intakes and, from this information, to estimate fatty acid tissue …

New Records And Ecological Remarks Regarding The Tribe Stomoxyini (Diptera: Muscidae) From Israel, Günter Müller, Jerome Hogsette, Vasiliy Kravchenko, Edita Revay, Yosef Schlein

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

The Stomoxyini is a small tribe with only ten genera and 49 known species worldwide (Zumpt 1973) belonging to the Muscidae, one of the largest dipteran. Apart from feeding occasionally on nectar (Müller et al. 2011a), the adult flies of this tribe are obligate blood feeders and can easily be recognized by their conspicuous proboscis adapted for biting and sucking blood (Zumpt 1973). Several members of the tribe, especially Stomoxys and Haematobia species, are major pests of domestic livestock. Two species, Stomoxys calcitrans (Linnaeus 1758) and Haematobia irritans (Linnaeus 1758), cause billions of USD in damages annually in the cattle …

Evapotranspiration Information Reporting: I. Factors Governing Measurement Accuracy, Richard G. Allen, Luis S. Pereira, Terry A. Howell, Marvin E. Jensen

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

More and more evapotranspiration models, evapotranspiration crop coefficients and associated measurements of evapotranspiration (ET) are being reported in the literature and used to develop, calibrate and test important ET process models. ET data are derived from a range of measurement systems including lysimeters, eddy covariance, Bowen ratio, water balance (gravimetric, neutron meter, other soil water sensing), sap flow, scintillometry and even satellite-based remote sensing and direct modeling. All of these measurement techniques require substantial experimental care and are prone to substantial biases in reported results. Reporting of data containing measurement biases causes substantial confusion and impedance to the advancement of …

Long-Term Water Balance And Conceptual Model Of A Semi-Arid Mountainous Catchment, G.M. Chauvin, G.N. Flerchinger, T.E. Link, Danny Marks, A.H. Winstral, M.S. Seyfried

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

Long-term water balance investigations are needed to better understand hydrologic systems, especially semi-arid mountainous catchments. These systems exhibit considerable interannual variability in precipitation as well as spatial variation in snow accumulation, soils, and vegetation. This study extended a previous 10-year water balance based on measurements and model simulations to 24 years for the Upper Sheep Creek (USC) catchment, a 26 ha, snow-fed, semi-arid rangeland headwater drainage within the Reynolds Creek Experimental Watershed in southwestern Idaho, USA. Additional analyses afforded by the additional years of data demonstrated that the variability between streamflow and annual precipitation (r² = 0.54) could be …

Beneath The Surface Of Global Change: Impacts Of Climate Change On Groundwater, Timothy R. Green, Makoto Taniguchi, Henk Kooi, Jason J. Gurdak, Diana M. Allen, Kevin M. Hiscock, Holger Treidel, Alice Aureli

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

Global change encompasses changes in the characteristics of inter-related climate variables in space and time, and derived changes in terrestrial processes, including human activities that affect the environment. As such, projected global change includes groundwater systems. Here, groundwater is defined as all subsurface water including soil water, deeper vadose zone water, and unconfined and confined aquifer waters. Potential effects of climate change combined with land and water management on surface waters have been studied in some detail. Equivalent studies of groundwater systems have lagged behind these advances, but research and broader interest in projected climate effects on groundwater have been …

Landform, Soil, And Plant Relationships To Nitrate Accumulation, Central Nevada, W.D. Nettleton, F.F. Peterson

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

Nitrate (NO₃ ⁻¹) accumulates in Haplocambids and Torrifluvents in inset fan and fan skirt positions in central Nevada. The soils store as much as 17,600 kg of NO3 −1 N ha−1 within the upper 208 cm. This paper provides an explanation. These Holocene soils receive NO₃ ⁻¹ N from mineralization of organic matter and other NO₃ ⁻¹ N sources including snowmelt. The NO₃ ⁻¹ is delivered to soils in the first part of snowmelt in run-off from the higher surfaces. The last part of the melt and the run-off, when sufficient, serve to move the …

A Novel Monoclonal Antibody Effective Against Lethal Challenge With Swine-Lineage And 2009 Pandemic H1n1 Influenza Viruses In Mice, Hongxia Shao, Jianqiang Ye, Amy L. Vincent, Nicole Edworthy, Andrea Ferrero, Aijian Qin, Daniel R. Perez

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

The HA protein of the 2009 pandemic H1N1 viruses (H1N1pdm) is antigenically closely related to the HA of classical North American swine H1N1 influenza viruses (cH1N1). Since 1998, through mutation and reassortment of HA genes from human H3N2 and H1N1 influenza viruses, swine influenza strains are undergoing substantial antigenic drift and shift. In this report we describe the development of a novel monoclonal antibody (S-OIV-3B2) that shows high hemagglutination inhibition (HI) and neutralization titers not only against H1N1pdm, but also against representatives of the α, β, and γ clusters of swine-lineage H1 influenza viruses. Mice that received a single intranasal …

Arkansas Cotton Variety Test 2010, Fred M. Bourland, A. B. Beach, D. P. Roberts Jr.

Arkansas Agricultural Experiment Station Research Series

The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant.

Spider Cognition, Robert R. Jackson, Fiona R. Cross

All Peer-Reviewed Publications

Spiders, having minute brains, were once considered simple, instinct-driven automatons, but research on spider biology is revealing increasing evidence of their cognitive abilities. In this review, we discuss the complex, flexible behaviour of spiders, especially salticids, and highlight how sometimes the cognitive character of spider behaviour closely parallels that of much bigger animals. This includes the use of selective attention (both visual and olfactory) and the use of planned detours. The implications of these findings, and how they relate to bigger issues traditionally associated with big-brain animals, such as 'representation' and 'mind', are discussed. Also discussed are issues relating to …

Construction Of A Ssr-Based Genetic Map And Identification Of Qtl For Domestication Traits Using Recombinant Inbred Lines From A Cross Between Wild And Cultivated Cowpea (V. Unguiculata (L.) Walp.), Mebeaselassie Andargie, Remy S. Pasquet, Bhavani S. Gowda, Geoffrey M. Muluvi, Michael P. Timko

All Peer-Reviewed Publications

Cowpea (Vigna unguiculata (L.) Walp.) is a grain legume commonly grown and consumed in many parts of the tropics and subtropics. A genetic linkage map was constructed using simple sequence repeat (SSR) markers and a recombinant inbred (RI) population of159 individuals derived from a cross between the breeding line 524B, a California Blackeye, and 219-01, a perennial wild cowpea from Kenya. Out of 912 primer combinations predicted to amplify SSRs in cowpea, 639 reliably produced amplification products in PCR assays and 202 (31.6%) were polymorphic between the two parents. These polymorphic SSRs were used to construct a genetic map consisting …

Isolation, Phylogeny And Evolution Of The Symrk Gene In The Legume Genus Lupinus L., Frédéric Mahé, Dragomira Markova, Rémy Pasquet, Marie Thérèse Misset, Abdelkader Aïnouche

All Peer-Reviewed Publications

SymRK is one of the key genes involved in initial steps of legume symbiotic association with fungi (mycorrhization) and nitrogen-fixing bacteria (nodulation). A large portion of the sequence encoding the extracellular domain of SYMRK was obtained for 38 lupine accessions and 2 outgroups in order to characterize this region, to evaluate its phylogenetic utility, and to examine whether its molecular evolutionary pattern is correlated with rhizobial diversity and specificity in Lupinus. The data suggested that, in Lupinus, SymRK is a single copy gene that shows good phylogenetic potential. Accordingly, SymRK provided additional support to previous molecular phylogenies, and shed additional …

Farmers' Markets In Kentucky: A Geospatial, Statistical, And Cultural Analysis, Elizabeth Ann Schmitz

Masters Theses & Specialist Projects

To assess what factors are driving the exponential growth of farmers’ markets in Kentucky, geospatial and statistical analysis of a database of 121 farmers’ markets was conducted. A statewide survey of market leaders and a case study of a single farmers’ market both identified reasons for growing support of farmers’ markets in Kentucky.

Market distribution, vendor levels, and gross sales were mapped against a backdrop of county urban classification, median household income, and education levels. Kruskal-Wallace analysis was used to identify if Kentucky’s rural, micropolitan, and metropolitan markets differ significantly in terms of their age, number of vendors, and market …

Estimating Maize Grain Yield From Crop Biophysical Parameters Using Remote Sensing, Noemi Guindin-Garcia

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

The overall objective of this investigation was to develop a robust technique to predict maize (Zea mays L.) grain yield that could be applied at a regional level using remote sensing with or without a simple crop growth simulation model. This study evaluated capabilities and limitations of the Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Index 250-m and MODIS surface reflectance 500-m products to track and retrieve information over maize fields. Results demonstrated the feasibility of using MODIS data to estimate maize green leaf area index (LAI_g). Estimates of maize LAI_g obtained from Wide Dynamic Range Vegetation …

Enhancing Out-Of-Season Production Of Tomatoes And Lettuce Using High Tunnels, Britney L. Hunter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The growing season for vegetable crops is limited by freezing temperatures in arid high elevation climates such as northern Utah. Logan, Utah (41.73 N, 111.83 W, 1382 m elevation) has a short, variable growing season with an average frost-free period of 135 days. Extending the growing season provides growers with an opportunity to extend revenue into a normally unproductive period and benefit from out-of-season price premiums. High tunnels have been used to effectively extend the growing season for numerous crops by providing cold temperature protection. However, limited high tunnel research has been performed in arid high elevation regions that experience …

Effect Of Mica Content On Surface Infiltration Of Soils In Northwestern Kern County, California, Steven Keyes Stakland

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A soils infiltration rate (IR) is the measured rate that soil is able to absorb water, either from precipitation or irrigation. A low IR can cause damage to crops if the necessary amount of water cannot penetrate to the plant roots in the time needed. The damage can be common in permanent plantings such as almond and pistachio orchards where regular tillage is avoided. This indicates a physical aspect to the problem because tillage increases IR. However, there is also an electrochemical side to infiltration problems because certain calcium surfactant treatments can increase IR. Various other methods have been used …

Arkansas Soybean Performance Tests 2010, R. D. Bond, D. G. Dombek, J. A. Still, R. M. Pryor

Arkansas Agricultural Experiment Station Research Series

Soybean variety and strain performance tests are conducted each year in Arkansas by the University of Arkansas Division of Agriculture Arkansas Crop Variety Improvement Program.