Digital Commons Network^™

Branched Chain Α-Ketoacid Dehydrogenase Kinase 111–130, A T Cell Epitope That Induces Both Autoimmune Myocarditis And Hepatitis In A/J Mice, Bharathi Krishnan, Chandirasegara Massilamany, Rakesh H. Basavalingappa, Arunakumar Gangaplara, Guobin Kang, Qingsheng Li, Francisco A. Uzal, Jennifer L. Strande, Gustavo A. Delhon, Jean-Jack Riethoven, David J. Steffen, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Introduction: Organ-specific autoimmune diseases are believed to result from immune responses generated against self-antigens specific to each organ. However, when such responses target antigens expressed promiscuously in multiple tissues, then the immune-mediated damage may be wide spread.

Methods: In this report, we describe a mitochondrial protein, branched chain α-ketoacid dehydrogenase kinase (BCKD_k) that can act as a target autoantigen in the development of autoimmune inflammatory reactions in both heart and liver.

Results: We demonstrate that BCKD_k protein contains at least nine immunodominant epitopes, three of which, BCKD_k 71–90, BCKD_k 111–130 and BCKD_k 141–160, …

Β1-Adrenergic Receptor Contains Multiple IaK And IeK Binding Epitopes That Induce T Cell Responses With Varying Degrees Of Autoimmune Myocarditis In A/J Mice, Rakesh H. Basavalingappa, Chandirasegaran Massilamany, Bharathi Krishnan, Arunakumar Gangaplara, Rajkumar A. Rajasekaran, Muhammad Z. Afzal, Jean-Jack Riethoven, Jennifer L. Strande, David J. Steffen, Jay Reddy

School of Veterinary and Biomedical Sciences: Faculty Publications

Myocarditis/dilated cardiomyopathy (DCM) patients can develop autoantibodies to various cardiac antigens and one major antigen is β1-adrenergic receptor (β₁AR). Previous reports indicate that animals immunized with a β₁AR fragment encompassing, 197–222 amino acids for a prolonged period can develop DCM by producing autoantibodies, but existence of T cell epitopes, if any, were unknown. Using A/J mice that are highly susceptible to lymphocytic myocarditis, we have identified β₁AR 171–190, β₁AR 181–200, and β₁AR 211–230 as the major T cell epitopes that bind major histocompatibility complex class II/IA^k or IE^{k …}

The Effect Of Feed Form On Diet Digestibility And Cecal Parameters In Rabbits, Isabella Corsato Alvarenga, Charles Gregory Aldrich, Micah Kohles

School of Veterinary and Biomedical Sciences: Faculty Publications

Fifteen New Zealand rabbits were randomly assigned to one of 3 dietary treatment groups of 5 animals each and fed pelleted, extruded, or muesli diets in a completely randomized design experiment. Rabbits were placed in individual cages with ad libitum access to water and food for 45 days acclimation followed by 30 days experimental period. Feed intake of rabbits fed pelleted and extruded diets was greater (p < 0.05) than rabbits fed the muesli diet (125.6 and 130.4 vs. 91.9 g/d), but weight change and feed efficiency were not affected by treatment. Diet digestibility among the treatments was inconsistent when comparing results obtained from total fecal collection and AIA (please define) as an internal marker. Rabbits fed extruded and pelleted diets had lower (p < 0.05) cecal pH (6.42 and 6.38 vs. 7.02, respectively), and higher (p < 0.05) production of SCFA (18.5 and 19.0 vs. 11.7 mM, respectively) than those fed muesli. The fermentation products from rabbits fed pelleted and extruded diets had a greater proportion of butyrate and less propionate than rabbits fed muesli. The results of this study indicate that the basal dietary composition had a greater impact on diet utilization and cecal fermentation than food form.

Mechanistic Understanding Of N-Glycosylation In Ebola Virus Glycoprotein Maturation And Function, Bin Wang, Yujie Wang, Dylan A. Frabutt, Xihe Zhang, Xiaoyu Yao, Dan Hu, Zhuo Zhang, Chaonan Liu, Shimin Zheng, Shi-Hua Xiang, Yong-Hui Zheng

School of Veterinary and Biomedical Sciences: Faculty Publications

The Ebola virus (EBOV) trimeric envelope glycoprotein (GP) precursors are cleaved into the receptor-binding GP₁ and the fusion-mediating GP₂ subunits and incorporated into virions to initiate infection. GP₁ and GP₂ form heterodimers that have 15 or two N-glycosylation sites (NGSs), respectively. Here we investigated the mechanism of how N-glycosylation contributes to GP expression, maturation, and function. As reported before, we found that, although GP₁ NGSs are not critical, the two GP₂ NGSs, Asn⁵⁶³ and Asn⁶¹⁸, are essential for GP function. Further analysis uncovered that Asn⁵⁶³ and Asn^{618 …}

A Novel Role Of Silibinin As A Putative Epigenetic Modulator In Human Prostate Carcinoma, Ioannis Anestopoulos, Aristeidis P. Sfakianos, Rodrigo Franco, Katerina Chlichlia, Mihalis I. Panayiotidis, David J. Kroll, Aglaia Pappa

School of Veterinary and Biomedical Sciences: Faculty Publications

Silibinin, extracted from milk thistle (Silybum marianum L.), has exhibited considerable preclinical activity against prostate carcinoma. Its antitumor and chemopreventive activities have been associated with diverse effects on cell cycle, apoptosis, and receptor-dependent mitogenic signaling pathways. Here we hypothesized that silibinin’s pleiotropic effects may reflect its interference with epigenetic mechanisms in human prostate cancer cells. More specifically, we have demonstrated that silibinin reduces gene expression levels of the Polycomb Repressive Complex 2 (PRC2) members Enhancer of Zeste Homolog 2 (EZH2), Suppressor of Zeste Homolog 12 (SUZ12), and Embryonic Ectoderm Development (EED) in DU145 and PC3 human prostate cancer cells, …

Pathogenesis, Molecular Genetics, And Genomics Of Mycobacterium Avium Subsp. Paratuberculosis, The Etiologic Agent Of Johne’S Disease, Govardhan Rathnaiah, Denise K. Zinniel, John P. Bannantine, Judith R. Stabel, Yrjo T. Grohn, Michael T. Collins, Raul G. Barletta

School of Veterinary and Biomedical Sciences: Faculty Publications

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiologic agent of Johne’s disease in ruminants causing chronic diarrhea, malnutrition, and muscular wasting. Neonates and young animals are infected primarily by the fecal–oral route. MAP attaches to, translocates via the intestinal mucosa, and is phagocytosed by macrophages. The ensuing host cellular immune response leads to granulomatous enteritis characterized by a thick and corrugated intestinal wall. We review various tissue culture systems, ileal loops, and mice, goats, and cattle used to study MAP pathogenesis. MAP can be detected in clinical samples by microscopy, culturing, PCR, and an enzyme-linked immunosorbent assay. There are commercial …

Ccpa Affects Infectivity Of Staphylococcus Aureus In A Hyperglycemic Environment, Markus Bischoff, Bodo Wonnenberg, Nadine Nippe, Naja J. Nyffenegger-Jann, Meike Voss, Christoph Beisswenger, Cord Sunderkotter, Virginie Molle, Quoc Thai Dinh, Frank Lammert, Robert Bals, Mathias Herrmann, Greg A. Somerville, Thomas Tschernig, Rosmarie Gaupp

School of Veterinary and Biomedical Sciences: Faculty Publications

Many bacteria regulate the expression of virulence factors via carbon catabolite responsive elements. In Gram-positive bacteria, the predominant mediator of carbon catabolite repression is the catabolite control protein A (CcpA). Hyperglycemia is a widespread disorder that predisposes individuals to an array of symptoms and an increased risk of infections. In hyperglycemic individuals, the bacterium Staphylococcus aureus causes serious, life-threatening infections. The importance of CcpA in regulating carbon catabolite repression in S. aureus suggests it may be important for infections in hyperglycemic individuals. To test this suggestion, hyperglycemic non-obese diabetic (NOD; blood glucose level ≥20 mM) mice were challenged with the …

The 1939 Dickinson-Belskie Birth Series Sculptures: The Rise Of Modern Visions Of Pregnancy, The Roots Of Modern Pro-Life Imagery, And Dr. Dickinson’S Religious Case For Abortion, Rose Holz

Women's and Gender Studies Program: Faculty Publications

This multidisciplinary essay examines the hugely influential—yet surprisingly overlooked—Birth Series sculptures. Created in 1939 by Dr. Robert L. Dickinson (obstetrician-gynecologist and leader of the Planned Parenthood Federation of America) and sculptor Abram Belskie, they illustrate the process of human development from fertilization through delivery. First displayed at the 1939–1940 World’s Fair in New York City, they were reproduced in a variety of forms and sent out across the United States and overseas. Hardly a brief fad, their popularity persisted into the 1980s. This essay has four purposes. First, it tells the stories of Dickinson and Belskie to appreciate their contributions …

Theoretically Proposed Optimal Frequency For Ultrasound Induced Cartilage Restoration, April D. Miller, Anuradha Subramanian, Hendrik J. Viljoen

Department of Chemical and Biomolecular Engineering: Faculty Publications

Background: Matching the frequency of the driving force to that of the system’s natural frequency of vibration results in greater amplitude response. Thus we hypothesize that applying ultrasound at the chondrocyte’s resonant frequency will result in greater deformation than applying similar ultrasound power at a frequency outside of the resonant bandwidth. Based on this resonant hypothesis, our group previously confirmed theoretically and experimentally that ultrasound stimulation of suspended chondrocytes at resonance (5 MHz) maximized gene expression of load inducible genes. However, this study was based on suspended chondrocytes. The resonant frequency of a chondrocyte does not only depend on the …

Enacting Efficacy In Early Career: Narratives Of Agency, Growth, And Identity, Elizabeth K. Niehaus, Jillian Reading, Crystal E. Garcia

Department of Educational Administration: Faculty Publications

Aim/Purpose: To explore how early career faculty in the field of higher education administration develop and enact their personal and professional identities.

Background: Participants sought to understand themselves, to understand their environments and the “rules” of the academic “game,” and to reconcile conflicts between their own values and identities and the expectations and culture of their environments.

Methodology: In-depth case studies of seventeen early career scholars in the field.

Contribution: The participants’ experiences underscore important implications for mentoring and socialization that takes into consideration the unique motivation and identity development of aspiring and new faculty members.

Findings: Identifies the early …

Living-Learning Programs Through The Years: A Reflection On Partnerships Between Students, Faculty, And Student Affairs, Kathleen J. Buell, Vaugn L. Love, Christina W. Yao

Department of Educational Administration: Faculty Publications

LIVING-LEARNING PROGRAMS (LLPs), also known as learning communities, offer students a shared academic focus within a residential community; thus, LLPs are considered ideal contexts for student learning. In 1994, Zeller highlighted Washington State University as an example of how learning communities can successfully incorporate faculty, students, and student affairs practitioners/departments into collaborative learning environments. This study provides an overview of changes that have occurred in the creation and implementation of LLPs during the past two decades. Using the University of Nebraska-Lincoln as a case study, this paper illustrates the growth and adaptation of LLPs over the years. Implications and innovations …

Stress-Responsive Pathways And Small Rna Changes Distinguish Variable Developmental Phenotypes Caused By Msh1 Loss, Mon-Ray Shao, Sunil Kumar Kenchanmane Raju, John D. Laurie, Robersy Sanchez, Sally A. Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Background: Proper regulation of nuclear-encoded, organelle-targeted genes is crucial for plastid and mitochondrial function. Among these genes, MutS Homolog 1 (MSH1) is notable for generating an assortment of mutant phenotypes with varying degrees of penetrance and pleiotropy. Stronger phenotypes have been connected to stress tolerance and epigenetic changes, and in Arabidopsis T-DNA mutants, two generations of homozygosity with the msh1 insertion are required before severe phenotypes begin to emerge. These observations prompted us to examine how msh1 mutants contrast according to generation and phenotype by profiling their respective transcriptomes and small RNA populations.

Results: Using RNA-seq, we analyze …

Influence Of Olfactory And Visual Cover On Nest Site Selection And Nest Success For Grassland-Nesting Birds, Dillon T. Fogarty, Dwayne Elmore, Samuel D. Fuhlendorf, Scott R. Loss

Department of Agronomy and Horticulture: Faculty Publications

Habitat selection by animals is influenced by and mitigates the effects of predation and environmental extremes. For birds, nest site selection is crucial to offspring production because nests are exposed to extreme weather and predation pressure. Predators that forage using olfaction often dominate nest predator communities; therefore, factors that influence olfactory detection (e.g., airflow and weather variables, including turbulence and moisture) should influence nest site selection and survival. However, few studies have assessed the importance of olfactory cover for habitat selection and survival. We assessed whether ground-nesting birds select nest sites based on visual and/or olfactory cover. Additionally, we assessed …

Patterns Of Gene Expression In Western Corn Rootworm (Diabrotica Virgifera Virgifera) Neonates, Challenged With Cry34ab1, Cry35ab1 And Cry34/35ab1, Based On Next-Generation Sequencing, Haichuan Wang, Seong-Il Eyun, Kanika Arora, Sek Yee Tan, Premchand Gandra, Etsuko N. Moriyama, Chitvan Khajuria, Jessica D. Jurzenski, Huarong Li, Maia Donahue, Kenneth E. Narva, Blair Siegfried

Department of Agronomy and Horticulture: Faculty Publications

With Next Generation Sequencing technologies, high-throughput RNA sequencing (RNAseq) was conducted to examine gene expression in neonates of Diabrotica virgifera virgifera (LeConte) (Western Corn Rootworm, WCR) challenged with individual proteins of the binary Bacillus thuringiensis insecticidal proteins, Cry34Ab1 and Cry35Ab1, and the combination of Cry34/Cry35Ab1, which together are active against rootworm larvae. Integrated results of three different statistical comparisons identified 114 and 1300 differentially expressed transcripts (DETs) in the Cry34Ab1 and Cry34/35Ab1 treatment, respectively, as compared to the control. No DETs were identified in the Cry35Ab1 treatment. Putative Bt binding receptors previously identified in other insect species were not identified …

Interaction Of 2,4-D Or Dicamba With Glufosinate For Control Of Glyphosate-Resistant Giant Ragweed (Ambrosia Trifida L.) In Glufosinate-Resistant Maize (Zea Mays L.), Zahoor A. Ganie, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Glyphosate-resistant (GR) giant ragweed is a problematic broadleaf weed in crops including maize and soybean in the Midwestern United States. Commercialization of crops with 2,4-D or dicamba and glufosinate resistance will allow post-emergence (POST) applications of these herbicides. Therefore, information is needed on how 2,4-D/dicamba will interact with glufosinate in various rate combinations. The objectives of this study were to evaluate the interaction of glufosinate plus 2,4-D and/or dicamba for control of GR giant ragweed, and to determine their effect on GR giant ragweed density, biomass, maize injury, and yield. Field experiments were conducted in 2013 and 2014 in a …

Changes In Soil Microbial Communities After 10 Years Of Winter Wheat Cultivation Versus Fallow In An Organic-Poor Soil In The Loess Plateau Of China, Hui Tian, Hui Wang, Xiaoli Hui, Zhaohui Wang, Rhae A. Drijber, Jinshan Liu

Department of Agronomy and Horticulture: Faculty Publications

Agricultural management methods, such as cultivation or fallowing, have led to significant changes in soil fertility and hence, crop yield. Such changes may have stemmed from changes in soil microbial communities and associated biogeochemical processes. This phenomenon is particularly true in organic-poor soil in the Loess Plateau of China. In this study, we examined three existing soil management regimes as part of a 10-year field experiment and evaluated their effects on fungal and bacterial community structures by performing high-throughput 454 pyrosequencing. These management regimes were (i) fertilized winter wheat (Triticum aestivum L.) (FW), (ii) continuous …

Regeneration And Invasion Of Cottonwood Riparian Forest Following Wildfire, Carissa L. Wonkka, Dirac L. Twidwell Jr., Christine H. Bielski, Craig R. Allen, Michael C. Stambaugh

Department of Agronomy and Horticulture: Faculty Publications

Populus deltoides is considered to be a weak resprouter and highly susceptible to wildfire, but few post-wildfire studies have tracked P. deltoides response and resprouting within the Great Plains of North America. Following a wildfire in southwestern Kansas, U.S.A., we surveyed burned and unburned areas of a cottonwood riparian forest along the Cimarron River that included a major understory invader, tamarisk (Tamarix ramosissima Ledeb.). We tested the following hypotheses, which are consistent with the current understanding of P. deltoides response to wildfire in the Great Plains: (1) regeneration of P. deltoides will be low in areas burned by the …

Genome-Guided Phylo-Transcriptomic Methods And The Nuclear Phylogentic Tree Of The Paniceae Grasses, Jacob D. Washburn, James C. Schnable, Gavin C. Conant, Thomas P. Brutnell, Ying Shao, Yang Zhang, Martha Ludwig, Gerrit Davidse, J. Chris Pires

Department of Agronomy and Horticulture: Faculty Publications

The past few years have witnessed a paradigm shift in molecular systematics from phylogenetic methods (using one or a few genes) to those that can be described as phylogenomics (phylogenetic inference with entire genomes). One approach that has recently emerged is phylo-transcriptomics (transcriptome-based phylogenetic inference). As in any phylogenetics experiment, accurate orthology inference is critical to phylo-transcriptomics. To date, most analyses have inferred orthology based either on pure sequence similarity or using gene-tree approaches. The use of conserved genome synteny in orthology detection has been relatively under-employed in phylogenetics, mainly due to the cost of sequencing genomes. While current trends …

Genetic Basis Of The Very Short Life Cycle Of ‘Apogee’ Wheat, Genqiao Li, Rungravee Boontung, Carol Powers, Vikas Belamkar, Tianrong Huang, Fang Miao, P. Stephen Baenziger, Liuling Yan

Department of Agronomy and Horticulture: Faculty Publications

Background: ‘Apogee’ has a very short life cycle among wheat cultivars (flowering 25 days after planting under a long day and without vernalization), and it is a unique genetic material that can be used to accelerate cycling breeding lines. However, little is known about the genetic basis of the super-short life of Apogee wheat.

Results: In this study, Apogee was crossed with a strong winter wheat cultivar ‘Overland’, and 858 F₂ plants were generated and tested in a greenhouse under constant warm temperature and long days. Apogee wheat was found to have the early alleles for four flowering time …

Genome-Wide Characterization Of Non-Reference Transposable Element Insertion Polymorphisms Reveals Genetic Diversity In Tropical And Temperate Maize, Xianjun Lai, James C. Schnable, Zhengqiao Liao, Jie Xu, Gengyun Zhang, Chuan Li, Erliang Hu, Tingzhao Rong, Yunbi Xu, Yanli Li

Department of Agronomy and Horticulture: Faculty Publications

Background: Maize was originally domesticated in a tropical environment but is now widely cultivated at temperate latitudes. Temperate and tropical maize populations have diverged both genotypically and phenotypically. Tropical maize lines grown in temperate environments usually exhibit delayed flowering, pollination, and seed set, which reduces their grain yield relative to temperate adapted maize lines. One potential mechanism by which temperate maize may have adapted to a new environment is novel transposable element insertions, which can influence gene regulation. Recent advances in sequencing technology have made it possible to study variation in transposon content and insertion location in large sets of …

Long-Term Tillage Impact On Soil Hydraulic Properties, Humberto Blanco-Canqui, Brian J. Weinhold, Virginia L. Jin, Marty R. Schmer, Leonard C. Kibet

Department of Agronomy and Horticulture: Faculty Publications

An improved understanding of the impact of tillage systems on soil hydraulic properties is necessary to conserve and manage soil water under a changing climate. The objective of this study was to specifically measure soil hydraulic properties (total porosity, water infiltration, saturated hydraulic conductivity, and water retention characteristics) in no-till, chisel plow, disk, and moldboard plow systems under rainfed continuous corn (Zea mays L.) after 35 yr on silty clay loam soils in eastern Nebraska. We measured ponded water infiltration (positive soil water pressure) and tension (-1 kPa matric potential) infiltration to exclude macropore (>125 mm diameter) flow. …

Reversing Resistance To Tembotrione In An Amaranthus Tuberculatus (Var. Rudis) Population From Nebraska, Usa With Cytochrome P450 Inhibitors, Maxwel C. Oliveira, Todd A. Gaines, Franck E. Dayan, Eric L. Patterson, Amit J. Jhala, Stevan Z. Knezevic

Department of Agronomy and Horticulture: Faculty Publications

Background: A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed a non-target-site resistance mechanism in this population. The main objective of this study was to explore the role of cytochrome P450 inhibitors in restoring the efficacy of HPPD-inhibitor herbicides on the HPPD-inhibitor resistant A. tuberculatus population from Nebraska, USA (HPPD-R).

Background: A population of Amaranthus tuberculatus (var. rudis) was confirmed resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor herbicides (mesotrione, tembotrione, and topramezone) in a seed corn/soybean rotation in Nebraska. Further investigation confirmed …

Can Cover Crop Use Allow Increased Levels Of Corn Residue Removal For Biofuel In Irrigated And Rainfed Systems?, S. J. Ruis, Humberto Blanco-Canqui, Paul J. Jasa, R. B. Ferguson, G. Slater

Department of Agronomy and Horticulture: Faculty Publications

Corn (Zea mays L.) residue removal at high rates can result in negative impacts to soil ecosystem services. The use of cover crops could be a potential strategy to ameliorate any adverse effects of residue removal while allowing greater removal levels. Hence, the objective of this study was to determine changes in water erosion potential, soil organic C (SOC) and total N concentration, and crop yields under early- and late-terminated cover crop (CC) combined with five levels of corn residue removal after 3 years on rainfed and irrigated no-till continuous corn in Nebraska. Treatments were no CC, early- and …

Using An Unmanned Aerial Vehicle To Evaluate Nitrogen Variability And Height Effect With An Active Crop Canopy Sensor, Brian Krienke, Richard B. Ferguson, Michael Schlemmer, Kyle Holland, David B. Marx, Kent M. Eskridge

Department of Agronomy and Horticulture: Faculty Publications

Ground-based active sensors have been used in the past with success in detecting nitrogen (N) variability within maize production systems. The use of unmanned aerial vehicles (UAVs) presents an opportunity to evaluate N variability with unique advantages compared to ground-based systems. The objectives of this study were to: determine if a UAV was a suitable platform for use with an active crop canopy sensor to monitor in-season N status of maize, if UAV’s were a suitable platform, is the UAV and active sensor platform a suitable substitute for current handheld methods, and is there a height effect that may be …

Dissecting The Genetic Basis Of Local Adaptation In Soybean, Nonoy B. Bandillo, Justin E. Anderson, Michael B. Kantar, Robert M. Stupar, James E. Specht, George L. Graef, Aaron J. Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max) is the most widely grown oilseed in the world and is an important source of protein for both humans and livestock. Soybean is widely adapted to both temperate and tropical regions, but a changing climate demands a better understanding of adaptation to specific environmental conditions. Here, we explore genetic variation in a collection of 3,012 georeferenced, locally adapted landraces from a broad geographical range to help elucidate the genetic basis of local adaptation. We used geographic origin, environmental data and dense genome-wide SNP data to perform an environmental association analysis and discover loci displaying steep …

Comparison Of Organic And Integrated Nutrient Management Strategies For Reducing Soil N2O Emissions, Rebecca F. Graham, Samuel E. Wortman, Cameron M. Pittelkow

Department of Agronomy and Horticulture: Faculty Publications

To prevent nutrient limitations to crop growth, nitrogen is often applied in agricultural systems in the form of organic inputs (e.g., crop residues, manure, compost, etc.) or inorganic fertilizer. Inorganic nitrogen fertilizer has large environmental and economic costs, particularly for low-input smallholder farming systems. The concept of combining organic, inorganic, and biological nutrient sources through Integrated Nutrient Management (INM) is increasingly promoted as a means of improving nutrient use efficiency by matching soil nutrient availability with crop demand. While the majority of previous research on INM has focused on soil quality and yield, potential climate change impacts have rarely been …

Rooting For Food Security In Sub-Saharan Africa, Nicolas Guilpart, Patricio Grassini, Justin Van Wart, Haishun Yang, Martin K. Van Ittersum, Lenny G.J. Van Bussel, Joost Wolf, Lieven Claessens, Johan G.B. Leenaars, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

There is a persistent narrative about the potential of Sub-Saharan Africa (SSA) to be a ‘grain breadbasket’ because of large gaps between current low yields and yield potential with good management, and vast land resources with adequate rainfall. However, rigorous evaluation of the extent to which soils can support high, stable yields has been limited by lack of data on rootable soil depth of sufficient quality and spatial resolution. Here we use location-specific climate data, a robust spatial upscaling approach, and crop simulation to assess sensitivity of rainfed maize yields to root-zone water holding capacity. We find that SSA could …

Can Yield Gap Analysis Be Used To Inform R & D Prioritisation?, P. A. J. Van Oort, K. Saito, I. Dieng, P. Grassini, K. G. Cassman, M. K. Van Ittersum

Department of Agronomy and Horticulture: Faculty Publications

The phrase “biggest bang for a buck” is associated with the policy making question that governments and development agencies face: “Where and which crops should receive highest priority for improving local and global food supply?”. A first step of prioritisation is to identify region x crop combinations for which high impact can be anticipated. We developed a new method for this prioritisation exercise and applied it to data from the Global Yield Gap and Water Productivity Atlas (GYGA). Our prioritisation distinguishes between two policy objectives (humanitarian and economic) and builds upon the relative yield gap and climate risk. Results of …

Supplemental Material For: Multi-Site Evaluation Of Apex For Water Quality: Ii. Regional Parameterization, Nathan O. Nelson, Claire Baffaut, John A. Lory, G.M.M.M. Anomaa Senaviratne, Ammar B. Bhandari, Ranjith P. Udawatta, Daniel W. Sweeney, Matt J. Helmers, Mike W. Van Liew, Antonio P. Mallarino, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

Model performance was assessed using Nash-Sutcliffe model efficiency (NSE), coefficient of determination (r²), and percent bias (PBIAS) as defined by Moriasi et al. (2007 and 2015). Threshold values indicating acceptable model performance based on these statistics are dependent on the spatial and temporal scales of the data, water quality constituents of interest, and the modeling objectives (Moriasi et al., 2015). Although some standard values have been suggested (Moriasi et al., 2007 and 2015), considerable variability exist in the published literature. For instance Ramanarayan et al. (1997) considered r² >0.5 and NSE >0.40 as satisfactory for simulation of …

Multisite Evaluation Of Apex For Water Quality: I. Best Professional Judgment Parameterization, Claire Baffaut, Nathan O. Nelson, John A. Lory, G.M.M.M. Anomaa Senaviratne, Ammar B. Bhandari, Ranjith P. Udawatta, Daniel W. Sweeney, Matt J. Helmers, M. W. Van Liew, Antonio P. Mallarino, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

The Agricultural Policy Environmental eXtender (APEX) model is capable of estimating edge-of-field water, nutrient, and sediment transport and is used to assess the environmental impacts of management practices. The current practice is to fully calibrate the model for each site simulation, a task that requires resources and data not always available. The objective of this study was to compare model performance for flow, sediment, and phosphorus transport under two parameterization schemes: a best professional judgment (BPJ) parameterization based on readily available data and a fully calibrated parameterization based on site-specific soil, weather, event flow, and water quality data. The analysis …