Plant Biology Commons^™

Ecophysiological Responses Of Tropical Woody Species To Ambient And Elevated Temperatures, Kelsey R. Carter

Dissertations, Master's Theses and Master's Reports

Tropical forests cycle one third of Earth’s carbon, yet we are still unsure how tropical vegetation will respond to climate warming. Tropical biomes experience a smaller temperature margin compared to other systems, possibly making them less capable of thermal adjustments. In addition, thermal responses of vegetation have been identified as one of the areas of greatest uncertainty for global carbon models. This dissertation works to quantify tropical forest photosynthetic responses to temperature as well as assessing physiological thermal acclimation of four tropical species. In Chapter, 2 we conducted a meta-analysis to investigate global tropical photosynthetic responses to temperature. We presented …

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …

The Effect Of Cold Stratification And Perigynia Removal On The Germination Of Three Prairie Carex Species, Christina M. Boeck Crew

Dissertations and Theses @ UNI

Sedges (Carex spp. Linneaus. [Cyperaceae]) are a major component of Midwestern U.S. tallgrass prairie and prairie wetland plant communities, yet they are often lacking in restoration projects because they can be difficult to germinate. Cold-wet stratification and perigynia removal have been shown to increase germination in some Carex species. The germination response of 3 native species, plains oval or shortbeak sedge (C. brevior (Dewey) Mack.), field oval or troublesome sedge (C. molesta Mack.), and prairie or Bicknell’s sedge (C. bicknellii Britton.), was tested to cold-wet stratification (28d) and perigynia removal in stored seed (10 months). Seed treatments …

The Mitochondrial Genome Of Eleusine Indica And Characterization Of Gene Content Within Poaceae, Nathan D. Hall, Hui Zhang, Jeffrey P. Mower, Joseph Scott Mcelroy, Leslie R. Goertzen

Department of Agronomy and Horticulture: Faculty Publications

Plant mitochondrial (mt) genome assembly provides baseline data on size, structure, and gene content, but resolving the sequence of these large and complex organelle genomes remains challenging due to fragmentation, frequent recombination, and transfers of DNA from neighboring plastids. Themt genome for Eleusine indica (Poaceae: goosegrass) is comprehensibly analyzed here, providing key reference data for an economically significant invasive species that is also the maternal parent of the allotetraploid crop Finger millet (Eleusine coracana). The assembled E. indica genome contains 33 protein coding genes, 6 rRNA subunits, 24 tRNA, 8 large repetitive regions 15 kb of transposable elements across a …

A Spatial Framework For Ex-Ante Impact Assessment Of Agricultural Technologies, José F. Andrade, Juan I. Rattalino Edreira, Andrew Farrow, Marloes P. Van Loon, Peter Q. Craufurd, Jairos Rurinda, Shamie Zingore, Jordan Chamberlin, Lieven Claessens, Julius Adewopo, Martin K. Van Ittersum, Kenneth G. Cassman, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Traditional agricultural research and extension relies on replicated field experiments, on-farm trials, and demonstration plots to evaluate and adapt agronomic technologies that aim to increase productivity, reduce risk, and protect the environment for a given biophysical and socio-economic context. To date, these efforts lack a generic and robust spatial framework for ex-ante assessment that: (i) provides strategic insight to guide decisions about the number and location of testing sites, (ii) define the target domain for scaling-out a given technology or technology package, and (iii) estimate potential impact from widespread adoption of the technology(ies) being evaluated. In this study, we developed …

Adaptation Of Photosynthesis To Water Deficit In The Reproductive Phase Of A Maize (Zea Mays L.) Inbred Line, H.F. Zheng, L.F. Xin, J.M. Guo, J. Mao, X.P. Han, L. Jia, B.Y. Zheng, C.G. Du, Roger W. Elmore, Q.H. Yang, R.X. Shao

Department of Agronomy and Horticulture: Faculty Publications

Photosynthesis is sensitive to water deficit (WD) stress. Maize (Zea mays L.) yield is vulnerable to water stress, especially if it occurs during the reproductive stage. In this study, the expression patterns of photosynthesis-related genes, together with photosynthetic gas-exchange and fluorescence parameters were investigated in a maize inbred line exposed to 50% of field water capacity (moderate WD) for 15 d after tassel emergence. The results demonstrated that WD down-regulated expression of psbA, psbB, psbC, psbP, psaA, psaB, and cab, especially at later periods of WD stress. Besides, with the increased WD stress, the steady decline in the value of …

Engineering Linear, Branched-Chain Triterpene Metabolism In Monocots, Chase Kempinski, Zuodong Jiang, Garrett Zinck, Shirley J. Sato, Zhengxiang Ge, Thomas E. Clemente, Joseph Chappell

Department of Agronomy and Horticulture: Faculty Publications

Triterpenes are thirty-carbon compounds derived from the universal five-carbon prenyl precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Normally, triterpenes are synthesized via the mevalonate (MVA) pathway operating in the cytoplasm of eukaryotes where DMAPP is condensed with two IPPs to yield farnesyl diphosphate (FPP), catalyzed by FPP synthase (FPS). Squalene synthase (SQS) condenses two molecules of FPP to generate the symmetrical product squalene, the first committed precursor to sterols and most other triterpenes. In the green algae Botryococcus braunii, two FPP molecules can also be condensed in an asymmetric manner yielding the more highly branched triterpene, botryococcene. Botryococcene …

Relationships Between Wildfire Burn Severity, Cavity-Nesting Bird Assemblages, And Habitat In An Eastern Ponderosa Pine Forest, Emma C. Keele, Victoria M. Donovan, Caleb P. Roberts, Sarah M. Nodskov, Carissa L. Wonkka, Craig R. Allen, Larkin A. Powell, David A. Wedin, David G. Angeler, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

Historically, eastern ponderosa pine (Pinus ponderosa) forests were described as sparse patches of old-growth trees maintained by frequent, low-severity fires; however, in recent decades, there have been a number of large mixed-severity wildfires throughout the range of these forests. Wildlife responses to severe fire disturbance in eastern ponderosa pine forests are not well understood. Our study investigates how cavity-nesting bird species in an eastern ponderosa pine forest are impacted by burn severity. The objectives of our study were to: (1) identify the community composition of cavity-nesting birds in a 27 y old burn of mixed severity, (2) assess …

Cover Crop Mixture Diversity, Biomass Productivity, Weed Suppression, And Stability, A. M. Florence, Leon G. Higley, R. A. Drijber, Charles A. Francis, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

The diversity-productivity, diversity-invasibility, and diversity-stability hypotheses propose that increasing species diversity should lead, respectively, to increased average biomass productivity, invasion resistance, and stability. We tested these three hypotheses in the context of cover crop mixtures, evaluating the effects of increasing cover crop mixture diversity on above ground biomass, weed suppression, and biomass stability. Twenty to forty cover crop treatments were replicated three or four times at eleven sites using eighteen species representing three cover crop species each from six pre-defined functional groups: cool-season grasses, cool-season legumes, cool-season brassicas, warm-season grasses, warm-season legumes, and warm-season broadleaves. Each species was seeded as …

Winter Wheat Grain Yield Response To Fungicide Application Is Influenced By Cultivar And Rainfall, Emmanuel Byamukama, Shaukat Ali, Jonathan Kleinjan, Dalitso N. Yabwalo, Christopher Graham, Melanie Caffe-Treml, Nathan D. Mueller, John Rickertsen, William A. Berzonsky

Department of Agronomy and Horticulture: Faculty Publications

Winter wheat is susceptible to several fungal pathogens throughout the growing season and foliar fungicide application is one of the strategies used in the management of fungal diseases in winter wheat. However, for fungicides to be profitable, weather conditions conducive to fungal disease development should be present. To determine if winter wheat yield response to fungicide application at the flowering growth stage (Feekes 10.5.1) was related to the growing season precipitation, grain yield from fungicide treated plots was compared to non-treated plots for 19 to 30 hard red winter wheat cultivars planted at 8 site years from 2011 through 2015. …

Flue Gas Desulfurization Gypsum As Soil Amendment, Dinesh Panday, Richard Ferguson, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Flue gas desulfurization (FGD) gypsum is one of the by-products of a coal-fired power generation plant. Coal is the world’s most abundant and widely distributed fossil fuel. After natural gas, coal is the second primary source of energy to generate electricity globally (more than 25%) and remains a key component of the fuel mix for power generation to meet electricity demand in most of the developing countries. The U.S., China and India are the top coal producers and consumers (for production of electricity from coal sources) in the world (OECD/IEA, 2014; IEA, 2016). However, in the U.S., its contribution to …

A Key Variant In The Cis-Regulatory Element Of Flowering Gene Ghd8 Associated With Cold Tolerance In Rice, Peng Wang, Yin Xiong, Rong Gong, Ying Yang, Kai Fan, Sibin Yu

Department of Agronomy and Horticulture: Faculty Publications

Variations in the gene promoter play critical roles in the evolution of important adaptive traits in crops, but direct links of the regulatory mutation to the adaptive change are not well understood. Here, we examine the nucleotide variations in the promoter region of a transcription factor (Ghd8) that control grain number, plant height and heading date in rice. We find that a dominant promoter type of subspecies japonica displayed a high activity for Ghd8 expression in comparison with the one in indica. Transgenic analyses revealed that higher expression levels of Ghd8 delayed heading date and enhanced cold …

A Tmeff2-Regulated Cell Cycle Derived Gene Signature Is Prognostic Of Recurrence Risk In Prostate Cancer, Constantin Georgescu, Joshua M. Corbin, Sandra Thibivilliers, Zachary D. Webb, Yan D. Zhao, Jan Koster, Kar-Ming Fung, Adam S. Asch, Jonathan D. Wren, Maria J. Ruiz-Echevarria

Department of Agronomy and Horticulture: Faculty Publications

Background: The clinical behavior of prostate cancer (PCa) is variable, and while the majority of cases remain indolent, 10% of patients progress to deadly forms of the disease. Current clinical predictors used at the time of diagnosis have limitations to accurately establish progression risk. Here we describe the development of a tumor suppressor regulated, cell-cycle gene expression based prognostic signature for PCa, and validate its independent contribution to risk stratification in several radical prostatectomy (RP) patient cohorts.

Methods: We used RNA interference experiments in PCa cell lines to identify a gene expression based gene signature associated with Tmeff2, an …

Impact Of Hurricane Katrina On The Coastal Systems Of Southern Louisiana, Wen-Ching Chuang, Tarsha Eason, Ahjond Garmestani, Caleb Roberts

Department of Agronomy and Horticulture: Faculty Publications

Natural disasters, such as hurricanes and forest fires, could trigger collapse and reorganization of social-ecological systems. In the face of external perturbations, a resilient system would have capacity to absorb impacts, adapt to change, learn, and if needed, reorganize within the same regime. Within this context, we asked how human and natural systems in Louisiana responded to Hurricane Katrina, and how the natural disaster altered the status of these systems. This paper discusses community resilience to natural hazards and addresses the limitations for assessing disaster resilience. Furthermore, we assessed social and environmental change in New Orleans and southern Louisiana through …

Genome-Wide Association Study For Multiple Biotic Stress Resistance In Synthetic Hexaploid Wheat, Madhav Bhatta, Alexey Morgounov, Vikas Belamkar, Stephen N. Wegulo, Abdelfattah A. Dababat, Gul Erginbas-Orakci, Mustapha El Bouhssini, Pravin Gautam, Jesse Poland, Nilufer Akci, Lutfu Demir, Ruth Wanyera, P. Stephen Baenziger

Department of Agronomy and Horticulture: Faculty Publications

Genetic resistance against biotic stress is a major goal in many wheat breeding programs. However, modern wheat cultivars have a limited genetic variation for disease and pest resistance and there is always a possibility of the evolution of new diseases and pests to overcome previously identified resistance genes. A total of 125 synthetic hexaploid wheats (SHWs; 2n = 6x = 42, AABBDD, Triticum aestivum L.) were characterized for resistance to fungal pathogens that cause wheat rusts (leaf; Puccinia triticina, stem; P. graminis f.sp. tritici, and stripe; P. striiformis f.sp. tritici) and crown rot (Fusarium spp.); …

Expression Of The Arabidopsis Wrinkled 1 Transcription Factor Leads To Higher Accumulation Of Palmitate In Soybean Seed, Pamela A. Vogel, Shen Bayon De Noyer, Hyunwoo Park, Hanh Nguyen, Lili Hou, Taity Changa, Hoang Le Khang, Ozan N. Ciftci, Tong Wang, Edgar B. Cahoon, Thomas Elmo Clemente

Department of Agronomy and Horticulture: Faculty Publications

Soybean (Glycine max [L.] Merr.) is a commodity crop highly valued for its protein and oil content. The high percentage of polyunsaturated fatty acids in soybean oil results in low oxidative stability, which is a key parameter for usage in baking, high temperature frying applications, and affects shelf life of packaged products containing soybean oil. Introduction of a seed-specific expression cassette carrying the Arabidopsis transcription factor WRINKLED1 (AtWRI1) into soybean, led to seed oil with levels of palmitate up to approximately 20%. Stacking of the AtWRI1 transgenic allele with a transgenic locus harbouring the mangosteen steroyl-ACP thioesterase (GmFatA) resulted …

Statistical And Machine Learning Methods Evaluated For Incorporating Soil And Weather Into Corn Nitrogen Recommendations, Curtis J. Ransom, Newell R. Kitchen, James J. Camberato, Paul R. Carter, Richard B. Ferguson, Fabian G. Fernandez, David W. Franzen, Carrie A. M. Laboski, D. Brenton Myers, Emerson D. Nafziger, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen (N) fertilizer recommendation tools could be improved for estimating corn (Zea mays L.) N needs by incorporating site-specific soil and weather information. However, an evaluation of analytical methods is needed to determine the success of incorporating this information. The objectives of this research were to evaluate statistical and machine learning (ML) algorithms for utilizing soil and weather information for improving corn N recommendation tools. Eight algorithms [stepwise, ridge regression, least absolute shrinkage and selection operator (Lasso), elastic net regression, principal component regression (PCR), partial least squares regression (PLSR), decision tree, and random forest] were evaluated using a dataset …

Predicting Soil Wind Erosion Potential Under Different Corn Residue Management Scenarios In The Central Great Plains, M. K. Rakkar, Humberto Blanco-Canqui, J. Tatarko

Department of Agronomy and Horticulture: Faculty Publications

Various models and simplified equations are available to predict wind erosion potential. However, their performance can be often site-specific, depending on soil characteristics and agronomic practices, warranting sitespecific model validations. Thus, in this study, we 1) validated the wind erodible fraction (WEF) predictive equations by Fryrear et al. (1994) and López et al. (2007) and 2) estimated the total soil loss with the Singleevent Wind Erosion Evaluation Program (SWEEP) using 3-yr measured data from six experiments located across a precipitation gradient in the central Great Plains. Each site had three corn (Zea mays L.) residue removal treatments: control (no …

Identification Of Quantitative Trait Loci For Plant Height, Crown Diameter, And Plant Biomass In A Pseudo-F2 Population Of Switchgrass, Megan Taylor, Carl-Erik Tornqvist, Xiongwei Zhao, R. W. Doerge, Michael D. Casler, Yiwei Jiang

Department of Agronomy and Horticulture: Faculty Publications

Switchgrass (Panicum virgatum) is a perennial warm-season grass that produces high biomass yield. Identification of mechanisms for genetic regulation of biomass traits has potential to facilitate genetic manipulation of switchgrass for enhancing biomass yield. The objective of this study was to identify quantitative trait loci for biomass-related traits in a pseudo-F₂ population of switchgrass derived from an upland cross with a lowland switchgrass cultivar. Plant height (HT), crown diameter (CD), and plant biomass (PB) were assessed in field studies in 2015 and 2016. Plant height was positively correlated with PB in both years but only correlated with …

Joint Use Of Genome, Pedigree, And Their Interaction With Environment For Predicting The Performance Of Wheat Lines In New Environments, Réka Howard, Daniel Gianola, Osval Montesinos-Lopez, Philomin Juliana, Ravi Singh, Jesse Poland, Sandesh Shrestha, Paulino Pérez-Rodriguez, José Crossa, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

Genome-enabled prediction plays an essential role in wheat breeding because it has the potential to increase the rate of genetic gain relative to traditional phenotypic and pedigree-based selection. Since the performance of wheat lines is highly influenced by environmental stimuli, it is important to accurately model the environment and its interaction with genetic factors in prediction models. Arguably, multi-environmental best linear unbiased prediction (BLUP) may deliver better prediction performance than single-environment genomic BLUP. We evaluated pedigree and genome-based prediction using 35,403 wheat lines from the Global Wheat Breeding Program of the International Maize and Wheat Improvement Center (CIMMYT). We implemented …

A World Of Cobenefits: Solving The Global Nitrogen Challenge, Benjamin Z. Houlton, Maya Almaraz, Viney Aneja, Amy T. Austin, Edith Bai, Kenneth G. Cassman, Jana E. Compton, Eric A. Davidson, Jan Willem Erisman, James N. Galloway, Baojing Gu, Guolin Yao, Luiz A. Martinelli, Kate Scow, William H. Schlesinger, Thomas P. Tomich, Chao Wang, Xin Zhang

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for (i) world hunger; (ii) soil, air, and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

A Two-Amino Acid Difference In The Coat Protein Of Satellite Panicum Mosaic Virus Isolates Is Responsible For Differential Synergistic Interactions With Panicum Mosaic Virus, R. V. Chowda-Reddy, Nathan A. Palmer, Serge Edme, Gautam Sarath, Frank A. Kovacs, Gary Y. Yuen, Robert Mitchell, Satyanarayana Tatineni

Department of Agronomy and Horticulture: Faculty Publications

Panicum mosaic virus (PMV) (genus Panicovirus, family Tombusviridae) and its molecular parasite, Satellite panicum mosaic virus (SPMV), synergistically interact in coinfected proso and pearl millet (Panicum miliaceum L.) plants resulting in a severe symptom phenotype. In this study, we examined synergistic interactions between the isolates of PMV and SPMV by using PMV-NE, PMV85, SPMV-KS, and SPMV-Type as interacting partner viruses in different combinations. Coinfection of proso millet plants by PMV-NE and SPMV-KS elicited severe mosaic, chlorosis, stunting, and eventual plant death compared with moderate mosaic, chlorotic streaks, and stunting by PMV85 and SPMV-Type. In reciprocal combinations, coinfection …

Evaluation Of Spray Pattern Uniformity Using Three Unique Analyses As Impacted By Nozzle, Pressure, And Pulse-Widthmodulation Duty Cycle, Thomas R. Butts, Joe D. Luck, Bradley K. Fritz, W. Clint Hoffmann, Greg R. Kruger

Department of Agronomy and Horticulture: Faculty Publications

BACKGROUND: The increasing popularity of pulse-width modulation (PWM) sprayers requires that application interaction effects on spray pattern uniformity be completely understood to maintain a uniform overlap of spray, thereby reducing crop injury potential andmaximizing coverage on target pests. The objective of this researchwas to determine the impacts of nozzle type (venturi vs. non-venturi), boom pressure, and PWMduty cycle on spray pattern uniformity. Research was conducted using an indoor spray patternator located at the University of Nebraska-Lincoln in Lincoln, NE, USA. Coefficient of variation (CV), root mean square error (RMSE), and average percent error (APE) were used to characterize spray pattern …

Benchmarking Irrigation Water Use In Producer Fields In The Us Central Great Plains, Katherine E. B. Gibson, Justin E. Gibson, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Efficient use of freshwater resources is necessary to balance food production and long-term sustainability of irrigated agricultural systems. Here we developed a framework to benchmark irrigation water use relative to crop yield for individual fields based on site-specific weather and soil. Subsequently, we used the framework to diagnose on-farm irrigation management, in relation to crop production, in maize and soybean producer fields in Nebraska (USA).We found actual irrigation to be similar to estimated irrigation water requirement in about half of the fields (i.e. small water surplus). Remarkably, these fields attained yields similar to fields where actual irrigation exceeded water requirements …

Comparing Infiltration Rates In Soils Managed With Conventional And Alternative Farming Methods: A Meta-Analysis, Andrea D. Basche, Marcia S. Delonge

Department of Agronomy and Horticulture: Faculty Publications

Identifying agricultural practices that enhance water cycling is critical, particularly with increased rainfall variability and greater risks of droughts and floods. Soil infiltration rates offer useful insights to water cycling in farming systems because they affect both yields (through soil water availability) and other ecosystem outcomes (such as pollution and flooding from runoff). For example, conventional agricultural practices that leave soils bare and vulnerable to degradation are believed to limit the capacity of soils to quickly absorb and retain water needed for crop growth. Further, it is widely assumed that farming methods such as no-till and cover crops can improve …

History Of Grass Breeding For Grazing Lands In The Northern Great Plains Of The Usa And Canada, Kenneth P. Vogel, John Hendrickson

Department of Agronomy and Horticulture: Faculty Publications

• In the early 1930s there were millions of acres of extensively degraded grazing lands and abandoned and eroded cropland in the Northern Plains of the United States and Canada.

• Grass breeding and plant materials programs were established by both the US and Canadian governments and cooperating universities to develop revegetation materials.

• Efforts of a small number of research locations and people resulted in grass cultivars or varieties that were used to revegetate and preserve the soil on millions of acres of land.

• This is a brief history of the people, agencies, and universities that developed these …

Do Cover Crops And Corn Residue Removal Affect Soil Thermal Properties?, Michael Sindelar, Humberto Blanco-Canqui, Virginia L. Jin, Richard B. Ferguson

Department of Agronomy and Horticulture: Faculty Publications

Soil thermal properties govern the transport and storage of heat in the soil. How management practices such as crop residue removal and cover crop (CC) use affect these soil properties is not well understood. For example, CCs could provide physical cover and improve soil properties after main crop residue removal and thus ameliorate the negative effects of residue removal on soil thermal properties. We measured changes in soil thermal properties including soil thermal conductivity, thermal diffusivity, volumetric heat capacity, and related properties under corn (Zea mays L.) residue removal with and without winter cereal rye (Secale cereale L.) …

Predicting Longitudinal Traits Derived From High-Throughput Phenomics In Contrasting Environments Using Genomic Legendre Polynomials And B-Splines, Mehdi Momen, Malachy T. Campbell, Harkamal Walia, Gota Morota

Department of Agronomy and Horticulture: Faculty Publications

Recent advancements in phenomics coupled with increased output from sequencing technologies can create the platform needed to rapidly increase abiotic stress tolerance of crops, which increasingly face productivity challenges due to climate change. In particular, high-throughput phenotyping (HTP) enables researchers to generate large-scale data with temporal resolution. Recently, a random regression model (RRM) was used to model a longitudinal rice projected shoot area (PSA) dataset in an optimal growth environment. However, the utility of RRM is still unknown for phenotypic trajectories obtained from stress environments. Here, we sought to apply RRM to forecast the rice PSA in control and water-limited …

Dedicated Bioenergy Crops And Water Erosion, Bharat Sharma Acharya, Humberto Blanco-Canqui, Robert B. Mitchell, Richard Cruse, David Laird

Department of Agronomy and Horticulture: Faculty Publications

Information on the water quality impact of perennial warmseason grasses (WSGs) when grown in marginal lands as dedicated energy crops is limited. We studied how WSGs affected runoff, sediment, and nutrient losses and related near-surface soil properties to those of no-till corn (Zea mays L.) on an eroded soil in southwestern Iowa and a center pivot corner in east-central Nebraska. The experiment at the eroded soil was established in 2012, and treatments included ‘Liberty’ switchgrass (Panicum virgatum L.) and no-till continuous corn. The experiment at the pivot corner was established in 2013 with ‘Liberty’ switchgrass, ‘Shawnee’ switchgrass, low-diversity grass …

Shifting Avian Spatial Regimes In A Changing Climate, Caleb P. Roberts, Craig R. Allen, David G. Angeler, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

In the present era of rapid global change, development of early warnings of ecological regime shifts is a major focus in ecology. Identifying and tracking shifts in spatial regimes is a new approach with potential to enhance understanding of ecological responses to global change. Here, we show strong directional non-stationarity of spatial regimes identified by avian community body mass data. We do this by tracking 46 years of avian spatial regime movement in the North American Great Plains. The northernmost spatial regime boundary moved >590 km northward, and the southernmost boundary moved >260 km northward. Tracking spatial regimes affords decadal …