Agricultural Science Commons^™

Influence Of Burning And Grazing Management Practices On Subirrigated Sandhill Meadow Hay Production, Tara M. Harms

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

Subirrigated meadows are a valuable forage resource to Sandhills ranching operations being used for hay production, grazing, or a combination of both. Practices that sustain meadow productivity should be encouraged to ensure a consistent feed supply for cattle. The potential influence of prescribed burning or pre-freeze and post-freeze grazing on forage production and quality are not well understood on these meadows. In grasslands, including meadows, excess dead plant material can accumulate, causing a potential reduction in forage yield and quality. Results of our three-year field study suggest that burning meadows in the spring is a suitable management option to remove …

Fungicide Resistance: Surveillance, Risk Assessment And Evolution In Two Soil-Borne Pathogens, Nikita Gambhir

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

Fungicide-resistant pathogens are an increasing threat to fungicide efficacy and plant health. The goal of this dissertation was to advance the foundational knowledge required to prevent and detect fungicide resistance development in the seedling disease pathogen, Rhizoctonia zeae and the white-mold pathogen, Sclerotinia sclerotiorum. Corn and soybean fields in 12 states (Iowa, Illinois, Indiana, Kansas, Kentucky, Michigan, Minnesota, Missouri, North Dakota, Nebraska, South Dakota, and Wisconsin) were surveyed for R. zeae. In vitro fungicide sensitivity was determined for 91 isolates to fludioxonil, sedaxane, and/or prothioconazole. Rhizoctonia zeae was sensitive to all fungicides (EC₅₀ < 3 µg/ml) except azoxystrobin (EC₅₀ > 100 µg/ml). In …

Evaluating The Untapped Potential Of U.S. Conservation Investments To Improve Soil And Environmental Health, Andrea Basche, Katherine Tully, Nora L. Alvarez-Berrios, Julian Reyes, Laura Lengnick, Tabitha Brown, Jennifer M. Moore, Rachel E. Schattman, Lana Koepke Johnson, Gabrielle Roesch-Mcnally

Department of Agronomy and Horticulture: Faculty Publications

There is increasing enthusiasm around the concept of soil health, and as a result, new public and private initiatives are being developed to increase soil health-related practices on working lands in the United States. In addition, billions of U.S. public dollars are dedicated annually toward soil conservation programs, and yet, it is not well quantified how investment in conservation programs improve soil health and, more broadly, environmental health. The Environmental Quality Incentives Program (EQIP) is one of the major U.S. public conservation programs administered on privately managed lands for which public data are available. In this research, we developed a …

Use Of An Active Canopy Sensor Mounted On An Unmanned Aerial Vehicle To Monitor The Growth And Nitrogen Status Of Winter Wheat, Jie Jiang, Zeyu Zhang, Qiang Cao, Yan Liang, Brian Krienke, Yongchao Tian, Yan Zhu, Weixing Cao, Xiaojun Liu

Department of Agronomy and Horticulture: Faculty Publications

Using remote sensing to rapidly acquire large-area crop growth information (e.g., shoot biomass, nitrogen status) is an urgent demand for modern crop production; unmanned aerial vehicle (UAV) acts as an effective monitoring platform. In order to improve the practicability and efficiency of UAV based monitoring technique, four field experiments involving different nitrogen (N) rates (0–360 kg N ha⁻¹ ) and seven winter wheat (Triticum aestivum L.) varieties were conducted at different eco-sites (Sihong, Rugao, and Xinghua) during 2015–2019. A multispectral active canopy sensor (RapidSCAN CS-45; Holland Scientific Inc., Lincoln, NE, USA) mounted on a multirotor UAV platform was used …

Perspectives On Low Temperature Tolerance And Vernalization Sensitivity In Barley: Prospects For Facultative Growth Habit, Maria Munoz-Amatriain, Javier Hernandez, Dustin Herb, P Stephen Baenziger, Anne Marie Bochard, Flavio Capettini, Ana Casas, Alfonso Cuesta-Marcos, Claus Einfeldt, Scott Fisk, Amelie Genty, Laura Helgerson, Markus Herz, Gongshe Hu, Ernesto Igartua, Ildiko Karsai, Toshiki Nakamura, Kazuhiro Sato, Kevin Smith, Eric Stockinger, William Thomas, Patrick Hayes

Department of Agronomy and Horticulture: Faculty Publications

One option to achieving greater resiliency for barley production in the face of climate change is to explore the potential of winter and facultative growth habits: for both types, low temperature tolerance (LTT) and vernalization sensitivity are key traits. Sensitivity to short-day photoperiod is a desirable attribute for facultative types. In order to broaden our understanding of the genetics of these phenotypes, we mapped quantitative trait loci (QTLs) and identified candidate genes using a genome-wide association studies (GWAS) panel composed of 882 barley accessions that was genotyped with the Illumina 9K single-nucleotide polymorphism (SNP) chip. Fifteen loci including 5 known …

Distribution Of Antibiotic-Resistant Enterobacteriaceae Pathogens In Potable Spring Water Of Eastern Indian Himalayas: Emphasis On Virulence Gene And Antibiotic Resistance Genes In Escherichia Coli, Ashish Kumar Singh, Saurav Das, Santosh Kumar, Varsha Rani Gajamer, Ishfaq Nabi Najar, Yanchen D. Lepcha, Hare Krishna Tiwari, Samer Singh

Department of Agronomy and Horticulture: Faculty Publications

Every year millions of people die due to fatal waterborne diseases around the world especially in developing countries like India. Sikkim, a northeastern state of India, greatly depends on natural water sources. About 80% of the population of Sikkim depends on natural spring water for domestic as well as agricultural use. Recent waterborne disease outbreaks in the state raises a concerning question on water quality. In this study, we analyzed water quality especially for the detection of Enterobacteriaceae members from four districts of the state. Isolation with selective culture media techniques and taxonomic characterization of Enterobacteriaceae bacteria with 16S rRNA …

Critical Period Of Palmer Amaranth Removal And Effects Of Late Season Herbicide Applications On Palmer Amaranth Seed Production, José Henrique Scarparo De Sanctis

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

Palmer amaranth is the most troublesome weed in agronomic crops in United States. Therefore, an integrated weed management approach is necessary to successfully manage this weed. The use of residual pre-emergence (PRE) herbicide applied at planting can delays the is one of the critical time of Palmer amaranth removal (CTPAR) giving farmers more time to prepare the weed control tactics and to preventing an unacceptable yield loss in soybean due to Palmer amaranth competition. Field experiments were conducted in 2018 and 2019 in a grower’s field infested with GR Palmer amaranth near Carleton, Nebraska, to determine the CTPAR in soybean …

Detailed Genetic Analysis For Identifying Qtls Associated With Drought Tolerance At Seed Germination And Seedling Stages In Barley, Yasser S. Moursi, Samar G. Thabet, Ahmed Amro, Mona F.A. Dawood, P Stephen Baenziger, Ahmed Sallam

Department of Agronomy and Horticulture: Faculty Publications

Drought induces several challenges for plant development, growth, and production. These challenges become more severe, in particular, in arid and semiarid countries like Egypt. In terms of production, barley ranks fourth after wheat, maize, and rice. Seed germination and seedling stages are critical stages for plant establishment and growth. In the current study, 60 diverse barley genotypes were tested for drought tolerance using two different treatments: control (0-PEG) and drought (20%-PEG). Twenty-two traits were estimated for seed germination and seedling parameters. All traits were reduced under drought stress, and a significant variation was found among genotypes under control and stress …

Hu Aquaponics Monitoring And Control System : European Annual Edunet Conference 2020, Rachel L. Fogle, Glenn P. Williams, Josh R. Krug

Harrisburg University Presidential Research Grants

The functional purpose of the HU Aquaponics Monitoring and Control System Project is to develop an environmental and plant monitoring and control system for the HU Aquaponics Lab, located in the Student Union. The project involves the design and implementation of technology that will regularly take measurements from the environment (e.g., air temperature, water temperature, pH, dissolved oxygen, etc). PLCnext Technology will systematically collect, store, and web-publish the measurement data for HU researchers and the public to use for scientific research.

Coal Char Affects Soil Ph To Reduce Ammonia Volatilization From Sandy Loam Soil, Dinesh Panday, Maysoon M. Mikha, Bijesh Maharjan

Department of Agronomy and Horticulture: Faculty Publications

Ammonia (NH₃) volatilization loss adversely affects N availability in soil-plant systems, reduces crop yield, and negatively impacts environment. Char (coal combustion residue), which contains up to 293 g kg⁻¹ total C by weight, has been shown to reduce NH₃ volatilization due to its considerably high surface area and cation exchange capacity. The NH₃ loss can be greatly affected by a shift in soil pH or urea hydrolysis. A 21-d laboratory study was conducted to evaluate the effects of char on soil pH, N transformations, and subsequent NH₃ volatilization in sandy loam soil. Two …

Economics Of Herbicide Programs For Weed Control In Conventional, Glufosinate, And Dicamba/Glyphosate-Resistant Soybean Across Nebraska, Adam M. Striegel, Kent M. Eskridge, Nevin C. Lawrence, Stevan Knezevic, Greg R. Kruger, Christopher A. Proctor, Gary Hein, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Despite widespread adoption of dicamba/glyphosate-resistant (DGR) soybean [Glycine max (L.) Merr.] in Nebraska and across the United States in recent years, economic information comparing herbicide programs with glufosinate-resistant (GLU-R) and conventional soybean is not available. The objectives of this study were to evaluate weed control efficacy, crop safety, gross profit margin, and benefit/cost ratios of herbicide programs with multiple sites of action in DGR, GLUR, and conventional soybean. Field experiments were conducted in 2018 and 2019 at three irrigated and two rain-fed locations across Nebraska, for a total of 10 site-years. Herbicides applied pre-emergence (PRE) that included herbicides with …

Growth, Physiological And Biochemical Responses Of Winged Bean (Psophocarpus Tetragonolobus) Towards Different Shade Levels, Murthazar Naim Raai

Student Works (2020-2029)

Ambiguous evidence suggests that shade could regulate the indeterminate growth habit of winged bean (Psophocarpus tetragonolobus), an underutilized protein-rich legume from the tropics. This study was conducted to examine the effects of three different shade levels, including 60% (heavy shade), 30% (moderate shade), and 0% (as control) on 25 traits associated with morphological features, photosynthetic and agronomic characteristics of winged bean. The shade-house experiment was conducted using a completely randomized design. Collectively, approximately 80% of the studied variables displayed significant differences (P< 0.05) between at least two shade treatments. Shading generally showed the most pronounced effect on the physiological traits of the legume, whereby the stomatal conductance, photosynthetic and transpiration rates differed significantly (P< 0.05) among plants for all treatments. Overall, non-shaded plants were observed to have superior growth and physiological responses than the shaded plants, especially being significantly taller with higher stomatal conductance, photosynthetic and transpiration rates. Interestingly, the moderately shaded plants exhibited the highest yield per plant (28.9 g �} 1.47), which significantly differed from the non-shaded (23.8 g �} 1.06) and heavily shaded (21.4 g �} 1.48) plants. These findings suggested that winged bean plants can adapt to partial shaded conditions or canopy cover, making it a potential nitrogen-fixing cash crop which can be planted together with fruit and oil trees in commercial plantations. Given that there were no significant differences between the moderately shaded and heavily plants with respect to their seed protein content (P>0.05), this project also demonstrates that winged bean can grow and yield well while maintaining its protein content …

Registration Of ‘Ne10589’ (Husker Genetics Brand Ruth) Hard Red Winter Wheat, P. Stephen Baenziger, Robert Graybosch, Devin J. Rose, Lan Xu, Mary Guttieri, Teshome Regassa, Robert N. Klein, Greg R. Kruger, Dipak Santra, Gary Hergert, Stephen Wegulo, Y. Jin, J. Kolmer, Gary Hein, Jeff Bradshaw, M.-S. Chen, G. Bai, R. L. Bowden, Ibrahim El-Basyoni, A. Lorenz

Department of Agronomy and Horticulture: Faculty Publications

With climate variation common in the U.S. Great Plains and particularly in Nebraska, wheat growers prefer broadly adapted cultivars. ‘NE10589’ (Reg. no. CV-1165, PI 675998) hard red winter wheat (Triticum aestivum L.) was developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA– ARS and released in January 2015 by the developing institutions. NE10589 was released primarily as a broadly adapted semi-dwarf cultivar for its superior performance under rainfed conditions throughout Nebraska and adjacent areas of the Great Plains. Its broad adaptation ensures that it will perform well under the typical environmental fluctuations that occur inNebraska. NE10589was selected …

Selection Signatures Across Seven Decades Of Hard Winter Wheat Breeding In The Great Plains Of The United States, Habtamu Ayalew, Mark E. Sorrells, Brett F. Carver, P. Stephen Baenziger, Xue-Feng Ma

Department of Agronomy and Horticulture: Faculty Publications

Classical plant breeding has been instrumental in changing the genetic makeup of crop plants for better ecological adaptation and improved quality. This paper provides insights of the genomic changes effected in hard winter wheat (Triticum aestivum L.) through decades of breeding and selection in the Great Plains of the United States. Population structure and differentiation analyses were conducted on 185 wheat cultivars released from 1943 to 2013. Cultivars were grouped into four distinct clusters using discriminant analysis of principal components (DAPC). One of the clusters was unique in that 15 out of the 18 individuals were recent releases (2000–2010), …

Simulating Winter Rye Cover Crop Production Under Alternative Management In A Corn-Soybean Rotation, Nilovna Chatterjee, Sotirios V. Archontoulis, Angela M Bastidas, Christopher A. Proctor, Roger W. Elmore, Andrea Basche

Department of Agronomy and Horticulture: Faculty Publications

The Agricultural Production Systems sIMulator (APSIM) was used to evaluate two alternative approaches for extending the cover crop growing window into corn (Zea mays L.) and soybean (Glycine max L.) crop rotations in Nebraska, USA.We evaluated how: (i) shifting corn planting dates (mid-April to early-June) and (ii) altering comparative relative maturity (CRM) corn hybrids (80 to 115 days) influence cover crop biomass and corn yields over a 30-year period. The APSIM model was tested using experimental data and was then used to simulate a range of cover crop planting and termination scenarios. Our results showed no significant yield …

Estimating Economic Minimums Of Mowing, Fertilizing, And Irrigating Turfgrass, Douglas J. Soldat, James T. Brosnan, Ambika Chandra, Roch E. Gaussoin, Alec Kowalewski, Bernd Leinauer, Frank S. Rossi, John C. Stier, J Bryan Unruh

Department of Agronomy and Horticulture: Faculty Publications

The public health crisis and economic recession caused by the COVID-19 pandemic have forced turfgrass industry professionals to re-evaluate standard practices. Minimum costs required to fertilize, irrigate, and mow turfgrasses can be roughly estimated using climate data, turfgrass physiology information, and resource costs. Although the actual minimum costs vary situationally and regionally, mowing golf putting greens optimally requires about US$34 per acre per month, whereas other turfgrass areas cost less than US$11 per acre per growing month. Fertilizer applications to turfgrass cost US$22 or less per acre per growing month. Irrigation costs (water and electricity for pumping) vary widely, with …

Soybean Barcsoysnp6k: An Assay For Soybean Genetics And Breeding Research, Qijian Song, Long Yan, Charles Quigley, Edward Fickus, He Wei, Linfeng Chen, Faming Dong, Susan Araya, Jinlong Liu, David Hyten, Vincent R. Pantalone, Randall L. Nelson

Department of Agronomy and Horticulture: Faculty Publications

The limited number of recombinant events in recombinant inbred lines suggests that for a biparental population with a limited number of recombinant inbred lines, it is unnecessary to genotype the lines with many markers. For genomic prediction and selection, previous studies have demonstrated that only 1000–2000 genome-wide common markers across all lines/accessions are needed to reach maximum efficiency of genomic prediction in populations. Evaluation of too many markers will not only increase the cost but also generate redundant information. We developed a soybean (Glycine max) assay, BARCSoySNP6K, containing 6000 markers, which were carefully chosen from the SoySNP50K assay based …

Functional Characterization Of Petiolule-Like Pulvinus (Plp) Gene In Abscission Zone Development In Medicago Truncatula And Its Application To Genetic Improvement Of Alfalfa, Juan Du, Shaoyun Lu, Maofeng Chai, Chuanen Zhou, Liang Sun, Yuhong Tang, Jaydeep Kolape, Zhaozhu Wen, Marjan Behzadirad, Tianxiu Zhong, Juan Sun, Yunwei Zhang, Zeng-Yu Wang

Department of Agronomy and Horticulture: Faculty Publications

Alfalfa (Medicago sativa L.) is one of the most important forage crops throughout the world. Maximizing leaf retention during the haymaking process is critical for achieving superior hay quality and maintaining biomass yield. Leaf abscission process affects leaf retention. Previous studies have largely focused on the molecular mechanisms of floral organ, pedicel and seed abscission but scarcely touched on leaf and petiole abscission. This study focuses on leaf and petiole abscission in the model legume Medicago truncatula and its closely related commercial species alfalfa. By analysing the petiolule-like pulvinus (plp) mutant in M. truncatula at phenotypic level (breakstrength and shaking …

Influence Of Cover Crop Management Practices On Rainfed Corn Production In Semi-Arid Western Nebraska, Alexandre Tonon Rosa

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

With the increased cover crop (CC) popularity, producers of semi-arid regions of western Nebraska are questioning whether they could successfully incorporate CC into their rainfed winter wheat (Triticum aestivum L.)-corn (Zea mays L.)-fallow rotations. The major concern is that CCs may deplete soil water affecting the subsequent crop. Therefore, three studies were established under rainfed conditions of western Nebraska to access the effects of CCs on soil water, soil compaction, nutrient cycling, weed demographics, residue coverage, and subsequent corn yield. The first study evaluated the influence of CC planting and termination times prior to corn establishment. Late termination …

Perioperative And Oncological Outcomes Following Minimally Invasive Versus Open Pancreaticoduodenectomy For Pancreatic Duct Adenocarcinoma, Rui Sun, Jiawen Yu, Yifan Zhang

Department of Agronomy and Horticulture: Faculty Publications

Background The outcomes of minimally invasive pancreaticoduodenectomy have not been adequately compared with those of open pancreaticoduodenectomy in patients with pancreatic ductal adenocarcinoma. We performed a meta‐analysis to compare the perioperative and oncological outcomes of these two pancreaticoduodenectomy procedures specifically in patients with pancreatic ductal adenocarcinoma.

Methods Before this study was initiated, a specific protocol was designed and has been registered in PROSEPRO (ID: CRD42020149438). Using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, PubMed, EMBASE, Web of Science, Cochrane Central Register, and ClinicalTrials.gov databases were systematically searched for studies published between January 1994 and October 2019. …

Evaluating Opportunities For Integrated Crop Livestock Systems In Eastern Nebraska, Elizabeth Kay Christenson

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

Current agricultural systems focused on production of few commodities are facing production, economic, and environmental challenges. To address these challenges, Integrated Crop Livestock Systems (ICLS) have emerged through three primary methods 1) perennial grasslands for grazing and/or hay production, 2) crop residue grazing, and 3) cover crop grazing. To evaluate potential of ICLS mitigating current challenges, a field scale model ICLS was developed in 2015. The ICLS includes 4-ha each of ‘Newell’ smooth bromegrass (Bromus inermis L.), ‘Liberty’ switchgrass (Panicum virgatum L.), and ‘Shawnee’ switchgrass. The ICLS also included 8-ha of continuous corn (Zea mays L.). In …

Soil-Nitrogen, Potentially Mineralizable-Nitrogen, And Field Condition Information Marginally Improves Corn Nitrogen Management, Jason Clark, Fabián G. Fernández, Kristen S. Veum, James J. Camberato, Paul R. Carter, Richard Ferguson, David W. Franzen, Daniel E. Kaiser, Newell R. Kitchen, Carrie A.M. Laboski, Emerson Nafziger, Carl J. Rosen, John E. Sawyer, John F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Anaerobic potentially mineralizable nitrogen (PMN) combined with preplant nitrate test (PPNT) or pre-sidedress nitrate test (PSNT) may improve corn (Zea mays L.) N management. Forty-nine corn N response studies were conducted across the U.S. Midwest to evaluate the capacity of PPNT and PSNT to predict grain yield, N uptake, and economic optimal N rate (EONR) when adjusted by soil sampling depth, soil texture, temperature, PMN, and initial NH₄–N from PMN analysis. Pre-plant soil samples were obtained for PPNT (0- to 30-, 30- to 60-, 60- to 90-cm depths) and PMN (0- to 30-cm depth) before corn planting …

Effects Of Pyric Herbivory On Prairie-Chicken (Tympanuchus Spp) Habitat, Heath D. Starns, Samuel D. Fuhlendorf, Robert D. Elmore, Dirac Twidwell, Eric T. Thacker, Torre J. Hovick, Barney Luttbeg

Department of Agronomy and Horticulture: Faculty Publications

The reduction and simplification of grasslands has led to the decline of numerous species of grassland fauna, particularly grassland-obligate birds. Prairie-chickens (Tympanuchus spp.) are an example of obligate grassland birds that have declined throughout most of their distribution and are species of conservation concern. Pyric herbivory has been suggested as a land management strategy for enhancing prairie-chicken habitat and stabilizing declining population trends. We assessed differences in vegetation structure created by pyric herbivory compared to fire-only treatments to determine whether pyric herbivory increased habitat heterogeneity for prairie-chickens, spatially or temporally. Our study was performed at four sites in the southern …

Production And Selection Of Quality Protein Popcorn Hybrids Using A Novel Ranking System And Combining Ability Estimates, Leandra Parsons, Ying Ren, Abou Yobi, Preston Hurst, Ruthie Angelovici, Oscar Rodriguez, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Popcorn varieties are agronomically sub-optimal and genetically limited compared to other maize subspecies. To increase genetic diversity and improve popcorn agronomics, dent germplasm has been introduced to popcorn with limited success and generally, major loss of popping. Between 2013 and 2018, 12 Quality Protein Popcorn (QPP) inbreds containing Quality Protein Maize (QPM) and popcorn germplasm were produced that maintained popping while carrying the opaque-2 allele conferring elevated kernel lysine. This is an opportune trait in the growing market for healthier snacks and a model for mining QPM traits into popcorn. We crossed QPP inbreds to explore the effects of heterosis …

Genomic Prediction Enhanced Sparse Testing For Multi-Environment Trials, Diego Jarquin, Reka Howard, José Crossa, Yoseph Beyene, Manje Gowda, Johannes W.R. Martini, Giovanny Covarrubias Pazaran, Juan Burgueño, Angela Pacheco, Martin Grondona, Valentin Wimmer, Boddupalli M. Prasanna

Department of Agronomy and Horticulture: Faculty Publications

“Sparse testing” refers to reduced multi-environment breeding trials in which not all genotypes of interest are grown in each environment. Using genomic-enabled prediction and a model embracing genotype · environment interaction (GE), the non-observed genotype-in-environment combinations can be predicted. Consequently, the overall costs can be reduced and the testing capacities can be increased. The accuracy of predicting the unobserved data depends on different factors including (1) how many genotypes overlap between environments, (2) in how many environments each genotype is grown, and (3) which prediction method is used. In this research, we studied the predictive ability obtained when using a …

Effects Of Tank Contamination And Impact Of Drift-Reducing Agents On Weed Control In Response To Dicamba Applications, Milos Zaric

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

Availability of dicamba-tolerant (DT) crops from 2017 provided farmers with additional herbicides for weed control management in row crops. However, the technology alike this one has concerns regarding dicamba off-target movement (OTM) causing undesirable effects on sensitive vegetation. Even though dicamba has high water solubility OTM that has often been overlooked when it comes to unintended crop exposure is dicamba tank contamination. Considering the complexity of spraying equipment soybean response may be expected even when small amounts of residues are left in the spray equipment. Typically, the same field spray equipment is used to perform herbicide application through growing season …

Irrigation, Carbon Amelioration, Nitrogen, And Stover Removal Effects On Continuous Corn, Marty Schmer, Virginia L. Jin, Richard B. Ferguson, Brian J. Wienhold

Department of Agronomy and Horticulture: Faculty Publications

Corn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a potential feedstock for cellulosic biofuels. Limited information is available on corn stover removal effects on grain yield under different irrigation rates, nitrogen (N) fertilizer rates, and practices to maintain soil carbon (C) and minimize soil erosion. We evaluated potential interactions between irrigation rate (full or limited), C amelioration practices (cover crop, surface-applied manure, or no amelioration practice), fertilizer N management (125 or 200 kg N ha⁻¹), and stover removal (residue removal or no residue removal), on no-till continuous corn …

Weed Control Efficacy Of Bio-Based Sprayable Mulch Films In Specialty Crop Systems, Eliott Gloeb

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

A sprayable bio-based mulch film (biofilm) could present a more sustainable weed management tool for specialty crop producers than conventional plastic mulch films while also offering flexibility in application patterns and timing. From 2017 to 2019, six greenhouse trials and four field trials were conducted at the University of Nebraska-Lincoln to study the effects of biofilm application on weed suppression and crop yields. Multiple application rates (0.81 L/m² - 9.78 L/m²) and application times (prior to weed emergence and post weed emergence) were tested. Corn starch, glycerol, keratin hydrolysate, corn gluten meal, corn zein, and isolated soy …

Characterizing Variation In Nitrogen Use Efficiency In Wheat Genotypes Using Proximal Canopy Sensing For Sustainable Wheat Production, Mohammed A. Naser, Raj Khosla, Louis Longchamps, Subash Dahal

Department of Agronomy and Horticulture: Faculty Publications

Global nitrogen use efficiency (NUE) for cereal production is marginal and is estimated to be about 33%. Remote sensing tools have tremendous potential for improving NUE in crops through efficient nitrogen management as well as the identification of high-NUE genotypes. The objectives of this study were (i) to identify and quantify the variation in NUE across 24 winter wheat genotypes (Triticum aestivum L.) and (ii) to determine if the normalized difference vegetation index (NDVI) could characterize the variability in NUE across wheat genotypes. This study was conducted in 2010 and 2011 in the semi-arid climate of Northeastern Colorado across dryland …

Genome Wide Association Study Reveals Plant Loci Controlling Heritability Of The Rhizosphere Microbiome, Siwen Deng, Daniel F. Caddell, Gen Xu, Lindsay Dahlen, Lorenzo Washington, Jinliang Yang, Devin Coleman-Derr

Department of Agronomy and Horticulture: Faculty Publications

Host genetics has recently been shown to be a driver of plant microbiome composition. However, identifying the underlying genetic loci controlling microbial selection remains challenging. Genome-wide association studies (GWAS) represent a potentially powerful, unbiased method to identify microbes sensitive to the host genotype and to connect them with the genetic loci that influence their colonization. Here, we conducted a population-level microbiome analysis of the rhizospheres of 200 sorghum genotypes. Using 16S rRNA amplicon sequencing, we identify rhizosphere-associated bacteria exhibiting heritable associations with plant genotype, and identify significant overlap between these lineages and heritable taxa recently identified in maize. Furthermore, we …