Agricultural Science Commons^™

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …

Comparing Organic And Conventional Yield Responses To Climate Variations, Joost Wilken Meyer

Graduate Theses and Dissertations

This thesis compares the responses of organic yields and conventional yields towards climate variations. To achieve this objective, weather variables such as growing season weather conditions (average temperature, precipitation, cloud cover, relative humidity, drought index), weather anomalies, the occurrence of severe or extreme droughts and excessive rainfalls, are combined with 23 data sets gathered from previous studies that compare organic and conventional yields from the same location and time periods. To narrow the scope, the thesis focuses on soybean, maize, and wheat production in Europe and North America. Study-level fixed-effects models are used to control for any time-invariant factors such …

Precise Nitrogen Recommendations Improve Economic And Environmental Outcomes In Arkansas Rice Production, Cristin Roberts

Graduate Theses and Dissertations

Soil testing has become an increasingly important tool in making agronomically efficient production management decisions. N-STaR is a N test used in rice production and is unique in its ability to selectively quantify soil organic-N compounds which are readily mineralizable for plant N uptake and contribute to growth and yield. This study uses historical (2002–2018) adoption rates of N-STaR, which is funded through Rice Checkoff funds, to calculate the total cost savings from N-STaR adoption. These cost savings alone would be the “typical” benefits used in a benefit-cost ratio of a public ally funded research program like N-STaR. However, we …

Seeding Rate Effects On Forage Mass And Vegetation Dynamics Of Cool-Season Grass Sod Interseeded With Sorghum-Sudangrass, John A. Guretzky, D. D. Redfearn

Department of Agronomy and Horticulture: Faculty Publications

Interseeding annual warm-season grasses into perennial cool-season grasses has the potential to increase summer forage mass and nutritive value. Knowledge of how seeding rate affects annual warm-season grass establishment, forage mass, and vegetation dynamics remains limited. From 2016–2017, we conducted a field experiment evaluating the effects of seeding rates on sorghum-sudangrass (Sorghum bicolor x S. bicolor var. sudanense) density and forage mass and on the frequency of occurrence of plant species in cool-season grass sod in Lincoln, NE. The experiment had a completely randomized design consisting of six replicates of four seeding rates [0, 14, 28, and 35 …

Impact Of Urbanization Trends On Production Of Key Staple Crops, José F. Andrade, Kenneth G. Cassman, Juan I. Rattalino Edreira, Fahmuddin Agus, Abdullahi Bala, Nanyan Deng, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Urbanization has appropriated millions of hectares of cropland, and this trend will persist as cities continue to expand. We estimate the impact of this conversion as the amount of land needed elsewhere to give the same yield potential as determined by differences in climate and soil properties. Robust spatial upscaling techniques, well-validated crop simulation models, and soil, climate, and cropping system databases are employed with a focus on populous countries with high rates of land conversion. We find that converted cropland is 30–40% more productive than new cropland, which means that projection of food production potential must account for expected …

Influence Of Surfactant-Humectant Adjuvants On Physical Properties, Droplet Size, And Efficacy Of Glufosinate Formulations, Estefania G. Polli, Guilherme S. Alves, Jesaelen Gizotti De Moraes, Greg Robert Kruger

Department of Agronomy and Horticulture: Faculty Publications

Glufosinate efficacy is inconsistent among weed species and under environmental conditions that favor rapid droplet drying. Surfactant-humectant adjuvants could maximize glufosinate efficacy by increasing wetting and penetration into the leaf surface while decreasing evaporation rate (ER). However, there is a lack of information in the literature about the interaction of surfactant-humectants adjuvants with glufosinate. The objective of this study was to investigate the influence of surfactanthumectant adjuvants on the physical properties, droplet size, and efficacy of two glufosinate formulations. Laboratory, greenhouse, and field studies were conducted at the Pesticide Application Technology Laboratory of the University of Nebraska- Lincoln. Treatment design …

Prosopis Glandulosa Persistence Is Facilitated By Differential Protection Of Buds During Low- And High-Energy Fires, Heath D. Starns, Carissa L. Wonkka, Matthew B. Dickinson, Alexandra G. Lodge, Morgan L. Treadwell, Kathleen L. Kavanagh, Douglas R. Tolleson, Dirac L. Twidwell Jr, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

Rangelands worldwide have experienced significant shifts from grass-dominated to woody-plant dominated states over the past century. In North America, these shifts are largely driven by overgrazing and landscape-scale fire suppression. Such shifts reduce productivity for livestock, can have broad-scale impacts to biodiversity, and are often difficult to reverse. Restoring grass dominance often involves restoring fire as an ecological process. However, many resprouting woody plants persist following disturbance, including fire, by resprouting from protected buds, rendering fire ineffective for reducing resprouting woody plant density. Recent research has shown that extreme fire (high-energy fires during periods of water stress) may reduce resprouting …

Making Agriculture Carbon Neutral Amid A Changing Climate: The Case Of South-Western Australia, Ross Kingwell

Climate Science Research Articles

Making Australian agriculture carbon neutral by 2050 is a goal espoused by several agricultural organisations in Australia. How costly might it be to attain that goal, especially when adverse climate change projections apply to agriculture in southern Australia? This study uses scenario analysis to examine agricultural emissions and their abatement via reforestation in south-western Australia under projected climate change. Most scenarios include the likelihood of agricultural emissions being reduced in the coming decades. However, the impact of projected adverse climate change on tree growth and tree survival means that the cost of achieving agricultural carbon neutrality via reforestation is forecast …

Genome-Wide Dna Polymorphism Analysis And Molecular Marker Development For The Setaria Italica Variety “Ssr41” And Positional Cloning Of The Setaria White Leaf Sheath Gene Siwls1, Hui Zhang, Sha Tang, James C. Schnable, Qiang He, Yuanzhu Gao, Mingzhao Luo, Guanqing Jia, Baili Feng, Hui Zhi, Xianmin Diao

Department of Agronomy and Horticulture: Faculty Publications

Genome-wide DNA polymorphism analysis and molecular marker development are important for forward genetics research and DNA marker-assisted breeding. As an ideal model system for Panicoideae grasses and an important minor crop in East Asia, foxtail millet (Setaria italica) has a high-quality reference genome as well as large mutant libraries based on the “Yugu1” variety. However, there is still a lack of genetic and mutation mapping tools available for forward genetics research on S. italica. Here, we screened another S. italica genotype, “SSR41”, which is morphologically similar to, and readily cross-pollinates with, “Yugu1”. High-throughput resequencing of “SSR41” …

A Chickpea Genetic Variation Map Based On The Sequencing Of 3,366 Genomes, Rajeev K. Varshney, Manish Roorkiwal, Shuai Sun, Prasad Bajaj, Annapurna Chitikineni, Mahendar Thudi, Narendra P. Singh, Xiao Du, Hari D. Upadhyaya, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

Zero hunger and good health could be realized by 2030 through effective conservation, characterization and utilization of germplasm resources1 . So far, few chickpea (Cicerarietinum) germplasm accessions have been characterized at the genome sequence level2 . Here we present a detailed map of variation in 3,171 cultivated and 195 wild accessions to provide publicly available resources for chickpea genomics research and breeding. We constructed a chickpea pan-genome to describe genomic diversity across cultivated chickpea and its wild progenitor accessions. A divergence tree using genes present in around 80% of individuals in one species allowed us to estimate the divergence of …

Using Uav Technology Paired With Multispectral Cameras To Assess Crown Rust Epidemics In Oats, Turner A. Graham

LSU Master's Theses

Crown rust, caused by Puccinia cornonata f. sp. avenae, is a common disease of oats (Avena sativa) found virtually everywhere oats are cultivated. This disease has caused yield losses of 10 to 40% worldwide. Early detection is important for effective management. A more recently utilized technology in agriculture is unmanned aerial vehicles (UAVs). UAVs, or drones, equipped with cameras are now being used as a resource to take images of fields to identify pests and other issues that may be occurring. Normalized differentiated vegetative index (NDVI) is a numerical indicator used to determine the vegetative health of …

Taxonomical Study Of Plant Species In Wadi Awaj (Al-Lasab) At Coastal Region Of Hadramout – Yemen, Mahroos Abdulla Ba-Hawerith, Mohammed Saeed Bin Qadim, Murad Mohammed Kanji, Dhekra Abdulla Maqram, Hassan Pyar Ali

Hadhramout University Journal of Natural & Applied Sciences

This study was carried out to identify the plant species of Wadi Awaj (Al-Lasab) in Hadhramout governorate. The results of the field survey identified a total of 47 plant species 26 families and 43 genera including 39 wild plant species grown naturally. The total number of cultivated plants was 6 plant species, only two plant species are grown as both wild and cultivated species. The dicots were 43 species while monocots were represented as 4 species. The most dominant families were: Fabaceae(8 species and 5 genera), Apocynaceae (5 species and 5 genera), Euphorbiaceae, Poaceae and Zygophyllaceae (3 species and 3 …

A Comparative Study Of Vegetation In Madar And Shohouh Valleys In Hadhramout, Salem Saeed Bacwud, Mohammed Saeed Khanbash, Salem Mohammed Bin Salman

Hadhramout University Journal of Natural & Applied Sciences

Bee rangeland plants are the basic sector of successful bee projects because they possess a verified range of species whose flowers contain nectar and pollen grains used in bee feeding. The study is conducted in Madar valley and Shohouh valley in Hadhramout valley. The objectives of the study are to compare bee plant species scattered in the two valleys. The survey of plants was carried out in February and March 2017 using systematic sampling plots collection. The plant survey recorded 22 families, 42 genera and 48 species in Madar valley as well as recording 25 families, 42 genera and 52 …

Economic Contribution Of Agriculture And Food To Arkansas’ Gross Domestic Product 1997-2020, Leah English, Jennie Popp, Wayne Miller

AAES Research Reports and Research Bulletins

Agricultural production, processing, and retail industries are major contributors to Arkansas’ GDP. Agriculture contributes to the state economy through direct agricultural production, value-added processing, and agricultural retail activities. The Agriculture and Food Sector, which is comprised of agricultural production, processing, and retail industries, promotes economic strength through various interactions with other industries. The use of non-agricultural goods and services as inputs into the agricultural sector promotes diversified growth in Arkansas’ economy and thus plays a vital role in maintaining economic stability throughout the state. This report 1) compares the relative size of the Agriculture and Food Sector in Arkansas with …

University Research On Winter Growing Of Container-Grown Strawberries Translates To Grower's Farm Trial, Stacy A. Adams, Ellen T. Paparozzi, Ryan Pekarek, Dave P. Lambe, George Meyer, M. Elizabeth Conley, Paul Read

Department of Agronomy and Horticulture: Faculty Publications

Strawberries are only seasonally available in Nebraska (NE). If an affordable heated structure can be designed, then opportunity exists to increase on-farm income by producing strawberries off-season during high-value market periods. A series of university greenhouse trials were conducted from 2010 to 2012. The varieties Evie-2 and Seascape were identified as being most productive under a low technology growing scheme. A new research project, which ran from fall to late spring (2013–2014), was designed to determine if this production scheme would translate to a commercial grower. Varieties Seascape and Evie-2 (each at two grades indicated by +) and San Andreas …

Growing Faba Beans On The South Coast Of Western Australia, Sarah Belli, Carla Milazzo, Emma Pearse, King Yin Lui, Grace Williams, Jeremy Lemon

Grain and other field crops published reports

Editors: Megan Abrahams, Andrew Blake and Vanessa Stewart (DPIRD)

Foreword

Thirty-three years ago I started work in Esperance on broadleaf crops. One of the best things my boss set up for me was arranging visits with several lupin farmers so I could follow their crops from seeding, through the growing season, to harvest. It was a great way to quickly get an idea of the choices farmers make and the reasons why.

With today’s busy lives, most farmers would be hard pressed to have the luxury of visiting many other farmers multiple times to learn how to grow a crop. …

Control Of Acetolactate Synthase Inhibitor/Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) In Isoxaflutole/Glufosinate/Glyphosate-Resistant Soybean, Jasmine Mausbach, Suat Irmak, Debalin Sarangi, John L. Lindquist, Amit J. Jhala

Department of Agronomy and Horticulture: Faculty Publications

Palmer amaranth is the most problematic and troublesome weed in agronomic cropping systems in the United States. Acetolactate synthase (ALS) inhibitor and glyphosate-resistant (GR) Palmer amaranth has been confirmed in Nebraska and it is widespread in several counties. Soybean resistant to isoxaflutole/glufosinate/glyphosate has been developed that provides additional herbicide site of action for control of herbicide-resistant weeds. The objectives of this study were to evaluate herbicide programs for control of ALS inhibitor/GR Palmer amaranth and their effect on Palmer amaranth density and biomass, as well as soybean injury and yield in isoxaflutole/glufosinate/glyphosate-resistant soybean. Field experiments were conducted in a grower's …

Identification And Validation Of High Ld Hotspot Genomic Regions Harboring Stem Rust Resistant Genes On 1b, 2a (Sr38), And 7b Chromosomes In Wheat, Shamseldeen Eltaher, Amira M.I. Mourad, P Stephen Baenziger, Stephen Wegulo, Vikas Belamkar, Ahmed Sallam

Department of Agronomy and Horticulture: Faculty Publications

Stem rust caused by Puccinia graminis f. sp. tritici Eriks. is an important disease of common wheat globally. The production and cultivation of genetically resistant cultivars are one of the most successful and environmentally friendly ways to protect wheat against fungal pathogens. Seedling screening and genome-wide association study (GWAS) were used to determine the genetic diversity of wheat genotypes obtained on stem rust resistance loci. At the seedling stage, the reaction of the common stem rust race QFCSC in Nebraska was measured in a set of 212 genotypes from F3:6 lines. The results indicated that 184 genotypes (86.8%) had different …

Spatial Frameworks For Robust Estimation Of Yield Gaps, Juan I. Rattalino Edreira, José F. Andrade, Kenneth G. Cassman, Martin K. Ittersum, Marloes P. Van Loon, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

Food security interventions and policies need reliable estimates of crop production and the scope to enhance production on existing cropland. Here we assess the performance of two widely used ‘top-down’ gridded frameworks (Global Agro-ecological Zones and Agricultural Model Intercomparison and Improvement Project) versus an alternative ‘bottom-up’ approach (Global Yield Gap Atlas). The Global Yield Gap Atlas estimates extra production potential locally for a number of sites representing major breadbaskets and then upscales the results to larger spatial scales. We find that estimates from top-down frameworks are alarmingly unlikely, with estimated potential production being lower than current farm production at some …

Development Of A Genomic Prediction Pipeline For Maintaining Comparable Sample Sizes In Training And Testing Sets Across Prediction Schemes Accounting For The Genotype-By-Environment Interaction, Reyna Persa, Martin Grondona, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

The global growing population is experiencing challenges to satisfy the food chain supply in a world that faces rapid changes in environmental conditions complicating the development of stable cultivars. Emergent methodologies aided by molecular marker information such as marker assisted selection (MAS) and genomic selection (GS) have been widely adopted to assist the development of improved genotypes. In general, the implementation of GS is not straightforward, and it usually requires cross-validation studies to find the optimum set of factors (training set sizes, number of markers, quality control, etc.) to use in real breeding applications. In most cases, these different scenarios …

A Machine Learning Interpretation Of The Contribution Of Foliar Fungicides To Soybean Yield In The North‐Central United States, Denis A. Shah, Thomas R. Butts, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Patricio Grassini, Shawn P. Conley, Paul D. Esker

Department of Agronomy and Horticulture: Faculty Publications

Foliar fungicide usage in soybeans in the north-central United States increased steadily over the past two decades. An agronomically-interpretable machine learning framework was used to understand the importance of foliar fungicides relative to other factors associated with realized soybean yields, as reported by growers surveyed from 2014 to 2016. A database of 2738 spatially referenced fields (of which 30% had been sprayed with foliar fungicides) was fit to a random forest model explaining soybean yield. Latitude (a proxy for unmeasured agronomic factors) and sowing date were the two most important factors associated with yield. Foliar fungicides ranked 7th out of …

Implications Of Cover Crop Planting And Termination Timing On Rainfed Maize Production In Semi-Arid Cropping Systems, Alexandre T. Rosa, Cody Creech, Roger W. Elmore, Daran Rudnick, John L. Lindquist, Miguel Fudolig, Liberty E. Butts, Rodrigo Werle

Department of Agronomy and Horticulture: Faculty Publications

Despite the potential to increase soil organic matter, cycle soil nutrients, and suppress weeds, there is a concern that cover crops (CCs) soil water use negatively impacts subsequent crops in water-limited environments. Cover crop management practices such as planting and termination timing may mitigate the detrimental impacts of CCs in semi-arid cropping systems. To determine the effects of CCs under water-limited environments, we evaluated the total CC biomass produced in the fall and spring, soil water content during the subsequent maize growing season, weed density and biomass, crop residue, and soil nutrients at the maize V6 development stage, and maize …

Contributions Of Individual Cover Crop Species To Rainfed Maize Production In Semi-Arid Cropping Systems, Alexandre T. Rosa, Cody Creech, Roger W. Elmore, Daran Rudnick, John L. Lindquist, Liberty Butts, Italo K. Pinho De Faria, Rodrigo Werle

Department of Agronomy and Horticulture: Faculty Publications

Cover crop (CC) species selection can contribute to reducing soil penetration resistance (brassica species), improved soil nitrogen (N) cycling (legume species), and suppression of weeds (grass species). However, one of the main concerns about including CCs in water-limited environments is soil water use and the consequences to subsequent crops. To determine the effects of individual CC species under water-limited environments, we evaluated fall and spring CC biomass produced, and soil water and N content, penetration resistance, weed density and biomass during the maize growing season, and maize grain yield. The experiment was conducted under a winter wheat-maize-fallow rotation at two …

Advancing Agricultural Research Using Machine Learning Algorithms, Spyridon Mourtzinis, Paul D. Esker, James E. Specht, Shawn P. Conley

Department of Agronomy and Horticulture: Faculty Publications

Rising global population and climate change realities dictate that agricultural productivity must be accelerated. Results from current traditional research approaches are difficult to extrapolate to all possible fields because they are dependent on specific soil types, weather conditions, and background management combinations that are not applicable nor translatable to all farms. A method that accurately evaluates the effectiveness of infinite cropping system interactions (involving multiple management practices) to increase maize and soybean yield across the US does not exist. Here, we utilize extensive databases and artificial intelligence algorithms and show that complex interactions, which cannot be evaluated in replicated trials, …

Final Selection Of Quality Protein Popcorn Hybrids, Leandra Parsons, Ying Ren, Abou Yobi, Ruthie Angelovici, Oscar Rodriguez, David R. Holding

Department of Agronomy and Horticulture: Faculty Publications

Quality Protein Popcorn (QPP) BC₂F₅ inbred lines were produced through an interpopulation breeding system between Quality Protein Maize dent (QPM) and elite popcorn germplasm. In 2019, five QPP F₁ hybrids were selected for further evaluation due to superior agronomics, endosperm protein quality, and popping quality traits. Though these BC₂F₅ QPP hybrids were phenotypically similar to their popcorn parents, the QPP cultivars conveyed slightly inferior popping characteristics when compared to the original popcorn germplasm. The objective of this study was twofold. First, BC₂F₅ inbred lines were crossed to their popcorn parents …

Farmers’ Adoption And Perceived Benefits Of Diversified Crop Rotations In The Margins Of U.S. Corn Belt, Tong Wang, Jin Hailong, Yubing Fan, Oladipo Obembe, Dapeng Li

Economics Faculty Publications

Monoculture and simplified two-crop rotation systems compromise the ecosystem services essential to crop production, diminish agricultural productivity, and cause detrimental effects on the environment. In contrast to the simplified two-crop rotation, diversified crop rotation (DCR) refers to rotation systems that contain three or more crops. Despite multiple benefits generated by DCR, its usage has dwindled over the past several decades. This paper examined determinants of farmers' adoption decisions and perceived benefits of DCR in the west margins of the U.S. Corn Belt where crop diversity has declined. We analyzed 708 farmer responses from a farmer survey conducted in the eastern …

Drift Reduction By Orienting Boom Sprayers’ Nozzles Against The Wind Direction, Medet Itmeç, Ali Bayat, Ömer Barış Özlüoymak

The Philippine Agricultural Scientist

Wind drift is a very critical issue in pesticide applications. In recent experiments, the application of pesticides is focus on precision farming. In this study, a spraying system that could manipulate trajectories of droplets to decrease drift was tested in a wind tunnel. Three nozzles (XR11002, AIXR11002 and TTJ6011002) were used at three operating pressures (200 kPa, 300 kPa, 400 kPa), with four orientation angles of nozzles against wind direction (0°, 5°, 10°, 15°), and three wind velocities (1.5, 2, and 2.5 m s^-1) with three repetitions. A statistical factorial CRD was used with Tukey Post Hoc Test …

Effects Of Micro-Rates Of 2,4-D And Dicamba On Lettuce And Pumpkin In Nebraska, Xinzheng Chen

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

Off-target herbicide injury from dicamba and 2,4-D is an increasingly common problem for specialty crop growers in the Midwestern United States. Both lettuce (Lactuca sativa L.) and pumpkin (Cucurbita spp.) are common specialty crops grown in Nebraska, and their proximity to corn and soybean production makes these crops susceptible to herbicide drift injury and yield loss. The objectives of this thesis research was to quantify crop injury and yield loss in greenhouse- and field-grown lettuce and field-grown pumpkins at different growth stages after exposure to sub-lethal doses of dicamba or 2,4-D. Dose response curves were generated to determine …

Genetic Diversity And Population Structure Of Sugarcane (Saccharum Officinarum L.) Collected From Seven Philippine Regions For Use As Breeding Stocks For Crop Improvement, Jan Leandro Acedera, Jhun Laurence Rasco, Jemimah Banganan, Antonio Lalusin

The Philippine Agricultural Scientist

Selection of parents for hybridization relies on the information on their genetic relationship and diversity which are essential in any breeding program. This study aimed to estimate the extent of genetic diversity and population structure of 76 sugarcane accessions from seven regions in the Philippines using 57 morphological characters and 50 microsatellite markers. The sugarcane collections exhibited moderate to high diversity with mean of H’ = 0.72 for qualitative and H’ = 0.75 for quantitative morphological characters, respectively. This is corroborated by the analysis of variance (ANOVA) of agronomic parameters, except for stalk length. Unweighted Pair Group Method with Arithmetic …

Three Lc-Ms Plant Metabolomics Studies Of Hop (Humulus) Species: Wild H. Neomexicanus, Drought Stress, And Agricultural Terroir, Taylan Morcol

Dissertations, Theses, and Capstone Projects

The hop plant (Humulus L., Cannabaceae) is a dioecious, perennial, twining vine with a long history of human use. Nowadays, hop plants are generally grown for their inflorescences (“cones”), which are used in brewing for their phytochemical metabolites. Many of these metabolites are involved in plant stress response and communication. Genetics and environment are two major factors that affect plant metabolism. In three separate metabolomics studies, this project examined the effects of both genetic and environmental factors on hop phytochemistry.

In the first study, 23 hop genotypes were grown in two different locations in the Pacific Northwest region of …