Agricultural Science Commons^™

Carbon Dioxide Fluxes In Corn–Soybean Rotation In The Midwestern U.S.: Inter- And Intra-Annual Variations, And Biophysical Controls, Guillermo Hernandez-Ramirez, Jerry L. Hatfield, Timothy B. Parkin, Thomas J. Sauer, John H. Prueger

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

Quantifying carbon dioxide (CO₂) fluxes in terrestrial ecosystems is critical for better understanding of global carbon cycling and observed changes in climate. This study examined year-round temporal variations of CO₂ fluxes in two biennial crop rotations during 4 year of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production. We monitored CO₂ fluxes using eddy-covariance (EC) and soil chambers in adjacent production fields near Ames, Iowa. Under the non-limiting soil water availability conditions predominant in these fields, diel and seasonal variations of CO₂ fluxes were mostly controlled by ambient temperature and …

Forage Soybean Yield And Quality Response To Water Use, David C. Nielsen

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

Forages could be used to diversify reduced and no-till dryland cropping systems from the traditional wheat (Triticum aestivum L.)-fallow system in the semiarid central Great Plains. Forages present an attractive alternative to grain and seed crops because of greater water use efficiency and less susceptibility to potentially devastating yield reductions due to severe water stress during critical growth stages. However, farmers need a simple tool to evaluate forage productivity under widely varying precipitation conditions. The objectives of this study were to (1) quantify the relationship between crop water use and dry matter (DM) yield for soybean (Glycine max …

Evaluating Decision Rules For Dryland Rotation Crop Selection, David C. Nielsen, Merle F. Vigil, Joseph G. Benjamin

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

No-till dryland winter wheat (Triticum aestivum L.)-fallow systems in the central Great Plains have more water available for crop production than the traditional conventionally tilled winter wheat-fallow systems because of greater precipitation storage efficiency. That additional water is used most efficiently when a crop is present to transpire the water, and crop yields respond positively to increases in available soil water. The objective of this study was to evaluate yield, water use efficiency (WUE), precipitation use efficiency (PUE), and net returns of cropping systems where crop choice was based on established crop responses to water use while incorporating a …

Towards Estimation Of Canopy Foliar Biomass With Spectral Reflectance Measurements, Lingli Wang, E. Raymond Hunt Jr., John J. Qu, Xianjun Hao, Craig S.T. Daughtry

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

Canopy foliar biomass, defined as the product of leaf dry matter content and leaf area index, is an important measurement for global biogeochemical cycles. This study explores the potential for retrieving foliar biomass in green canopies using a spectral index, the Normalized Dry Matter Index (NDMI). This narrow-band index is based on absorption at the C–H bond stretch overtone and is correlated with leaf dry matter content in fresh green leaves. PROSPECT and SAIL model simulations suggest that the NDMI at the canopy scale is able to minimize the effects of leaf thickness and leaf water content and to maximize …

Development Of Simple Sequence Repeat Markers For Chionanthus Retusus (Oleaceae) And Effective Discrimination Of Closely Related Taxa, R. S. Arias, Timothy A. Rinehart, Richard T. Olsen, Joseph H. Kirkbride Jr., Brian E. Scheffler

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

The genus Chionanthus (Oleaceae Hoffmans. & Link) includes deciduous or evergreen trees and shrubs distributed widely in tropical and sub-tropical areas, including a few temperate species. Although Chionanthus species are planted as ornamental garden plants and commercialized for natural products, genetic information for Chionanthus spp. is lacking. We created micro satellite-enriched libraries of Chionanthus retusus Lindl. & Paxton, assembled 1072 contigs, and detected 1010 repeats. The frequency of the repeats decreased with the increase in repeat length, and the most abundant motifs were: AG, AC, AAG, ACC, AT, and ACTC. We screened 384 markers on 12 accessions of four related …

Identification Of Wild Apple Germplasm (Malus Spp.) Accessions With Resistance To The Postharvest Decay Pathogens Penicillium Expansum And Colletotrichum Acutatum, W. M. Jurick Ii, W. J. Janisiewicz, R. A. Saftner, I. Vico, V. L. Gaskins, E. Park, P. L. Forsline, G. Fazio, W. S. Conway

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

Penicillium expansum and Colletotrichum acutatum cause blue mould and bitter rot of apples during storage which results in significant economic losses. Resistance to these pathogens in commercial apple cultivars has not been documented in the literature. An apple germplasm collection, from the centre of origin in Kazakhstan, is maintained in Geneva, New York. This collection represents a more diverse apple gene pool than commercial cultivars and was evaluated for resistance to the pathogens that cause blue mould and bitter rot. Resistance reactions were skewed towards susceptibility for both fungi and comprised the majority of accessions examined. However, resistance to P. …

Spatial Ramifications Of Crop Selection: Water Quality And Biomass Energy, M. P. Russelle, D. W. Kelley, A. S. Birr, D. C. Tiffany

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

The use of GIS in concert with simple or complex simulation modeling provides an unparalleled way to generate new data and to help a variety of audiences understand spatial patterns of data. From improved understanding, policy incentives can be crafted to reduce adverse environmental impacts of agricultural production at lower costs than would be necessary otherwise. In this chapter, two case studies demonstrate how GIS and modeling can be used to understand how crop selection and soils interact to effect environmental outcomes across an agricultural landscape. We addressed the needs of two distinctly different audiences: (1) a public drinking water …

Nutritional Plane And Selenium Supply During Gestation Affect Yield And Nutrient Composition Of Colostrum And Milk In Primiparous Ewes, A. M. Meyer, J. J. Reed, T. L. Neville, J. F. Thorson, K. R. Maddock-Carlin, J. B. Taylor, L. P. Reynolds, D. A. Redmer, J. S. Luther, C. J. Hammer, K. A. Vonnahme, J. S. Caton

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

The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/ kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed …

Putting The Whole Grain Puzzle Together: Health Benefits Associated With Whole Grains—Summary Of American Society For Nutrition 2010 Satellite Symposium, Satya S. Jonnalagadda, Lisa Harnack, Rui Hai Liu, Nicola Mckeown, Chris Seal, Simin Liu, George C. Fahey

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

The symposium “Putting the Whole Grain Puzzle Together: Health Benefits Associated with Whole Grains” sponsored by the ASN brought together researchers to review the evidence regarding the health benefits associated with whole grains. Current scientific evidence indicates that whole grains play an important role in lowering the risk of chronic diseases, such as coronary heart disease, diabetes, and cancer, and also contribute to body weight management and gastrointestinal health. The essential macro- and micronutrients, along with the phytonutrients present in whole grains, synergistically contribute to their beneficial effects. Current evidence lends credence to the recommendations to incorporate whole grain foods …

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 …

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 …

Past And Projected Future Changes In Snowpack And Soil Frost At The Hubbard Brook Experimental Forest, New Hampshire, Usa, John L. Campbell, Scott V. Ollinger, Gerald N. Flerchinger, Haley Wicklein, Katharine Hayhoe, Amey S. Bailey

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

Long-term data from the Hubbard Brook Experimental Forest in New Hampshire show that air temperature has increased by about 1°C over the last half century. The warmer climate has caused significant declines in snow depth, snow water equivalent and snow cover duration. Paradoxically, it has been suggested that warmer air temperatures may result in colder soils and more soil frost, as warming leads to a reduction in snow cover insulating soils during winter. Hubbard Brook has one of the longest records of direct field measurements of soil frost in the United States. Historical records show no long-term trends in maximum …

Molecular Mapping Of Greenbug Resistance Genes Gb2 And Gb6 In T1al.1rs Wheat-Rye Translocations, H. Lu, Jackie C. Rudd, J. D. Burd, Y. Weng

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

Two greenbug resistance genes Gb2 and Gb6 derived from the same donor rye line 'Insave', are present in wheat germplasm lines 'Amigo' and 'GRS1201', respectively as 1AL.1RS wheat-rye translocations. The allelic relationship between the two genes has not been determined, and no molecular markers for Gb6 are available. In this study, molecular mapping of Gb2 and Gb6 was performed in a mapping population derived from a cross between 'N96L9970' (Gb6Gb6) and 'TAM 107' (Gb2Gb2). Segregation among F_2:3 families of host responses to infestation of greenbug biotypes E and KS-1 revealed that Gb2 and Gb6 were …

Relationship Of Cooked-Rice Nutritionally Important Starch Fractions With Other Physicochemical Properties, James Patindol, Harmeet Guraya, Elaine Champagne, Ming-Hsuan Chen, Anna Mcclung

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

Sixteen rice cultivars representing five cytosine-thymine repeat (CT_n) microsatellite genetic marker groups were analyzed for their cooked rice nutritionally important starch fractions (NISFs, which include rapidly digestible (RDS), slowly digestible (SDS), and resistant starch (RS)), basic grain quality indices (apparent amylose (AM), crude protein (CP), alkali spreading value (AS), and gel consistency (GC)), pasting characteristics, and thermal properties. Chemometric tools (bivariate correlation, principal component analysis, multiple linear regression, and partial least squares regression) were used to establish the association of NISF with other milled rice physicochemical properties. CT₁₁ was generally associated with high percentages of RS and …

Regulatory Control Of High Levels Of Carotenoid Accumulation In Potato Tubers, Xiangjun Zhou, Ryan Mcquinn, Zhangjun Fei, Anne-Marie A. Wolters, Joyce Van Eck, Charles Brown, James J. Giovannoni, Li Li

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

Potato (Solanum tuberosum L.) tubers contain a wide range of carotenoid contents. To decipher the key factors controlling carotenoid levels in tubers, four potato lines (Atlantic, Désirée, 91E22 and POR03) were examined by a combination of biochemical, molecular and genomics approaches. These lines contained incremental levels of carotenoids, which were found to be associated with enhanced capacity of carotenoid biosynthesis as evident from norflurazon treatment. Microarray analysis of high and low carotenoid lines (POR03 versus Atlantic) revealed 381 genes that showed significantly differential expression. The carotenoid metabolic pathway genes b-carotene hydroxylase 2 (BCH2) and b-carotene hydroxylase 1 (BCH1), along …

Invited Commentary: Dietary Pattern Analysis, Fumiaki Imamura, Paul F. Jaques

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

The analytic approaches used in nutritional epidemiology for dietary pattern analyses share common characteristics with those of genetic epidemiology. In this issue of the Journal, Gorst-Rasmussen et al. (Am J Epidemiol. 2011;173(10):1097–1104) discuss one such approach. Application of methods used in genetic pattern analyses to nutritional epidemiology could prove valuable but raises important issues that need to be considered because dietary and genetic studies often address different types of questions in analyzing interrelated variables. These different aims require statistical methods that assume different characteristics of the underlying patterns. The authors briefly describe such differences to facilitate interpretation and …

Physiology And Endocrinology Symposium: Role Of The Oviduct In Maintaining Sustained Fertility In Hens, M. R. Bakst

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

In poultry, sperm transferred by natural mating or AI into the distal end of the vagina immediately begin their ascent to the uterovaginal junction (UVJ) at the anterior end of the vagina. However, due to an intense selection process in the vagina, less than 1% of the sperm transferred actually reach the UVJ. Those sperm that do reach the UVJ enter numerous tubular invaginations of the surface epithelium of the vagina located in the UVJ mucosa, collectively referred to as the sperm-storage tubules (SST). Sperm residing in the SST lumen are capable of surviving up to several weeks while retaining …

The Rural Growth Trifecta: Outdoor Amenities, Creative Class And Entrepreneurial Context, David A. Mcgranahan, Timothy R. Wojan, Dayton M. Lambert

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

Recent work challenges the notion that attracting creative workers to a place is sufficient for generating local economic growth. In this article, we examine the problem of sustaining robust growth in the periphery of the USA, demonstrating the contingent nature of talent as an engine for economic growth. We test the hypothesis that rural growth in the knowledge economy is dependent on the ability to utilize new knowledge, perhaps generated elsewhere, in addressing local economic challenges. Tests confirm that the interaction of entrepreneurial context with the share of the workforce employed in the creative class is strongly associated with growth …

Upland Contribution Of Sediment And Runoff During Extreme Drought: A Study Of The 1947–1956 Drought In The Blackland Prairie, Texas, P.M. Allen, R.D. Harmel, J.A. Dunbar, J. G. Arnold

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

The 1950s drought severely impacted a 1.1 million km² area in the central US. This drought, along with the famous 1930s drought, was among the most severe of the 20th century for large areas and is the drought of record for water supply planning in Texas. At the USDA-ARS Riesel Watersheds during the drought, average annual rainfall was reduced 27%, which produced 75% less runoff and 35% less sediment yield. Rainfall intensity during the drought was, however, typically greater than for the non-drought period. Based on long-term data from the Riesel Watersheds, the mean, 75th, 90th, and 95th percentile …

26th Hohenheim Consensus Conference, September 11, 2010 Scientific Substantiation Of Health Claims: Evidence-Based Nutrition, Hans Konrad Biesalski, Peter J. Aggett, Robert Anton, Paul S. Bernstein, Jeffrey Blumberg, Robert P. Heaney, Jeya Henry, John M. Nolan, David P. Richardson, Ben Van Ommen, Renger F. Witkamp, Ger T. Rijkers, Iris Zöllner

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

Objective: The objective was to define the term evidence based nutrition on the basis of expert discussions and scientific evidence.

Methods and procedures: The method used is the established Hohenheim Consensus Conference. The term “Hohenheim Consensus Conference” defines conferences dealing with nutrition-related topics. The major aim of the conference is to review the state of the art of a given topic with experts from different areas (basic science, clinicians, epidemiologists, etc.). Based on eight to 12 questions, the experts discuss short answers and try to come to a consensus. A scientifically based text is formulated that justifies the …