Agronomy and Crop Sciences Commons^™

Development And Evaluation Of An Automated Tactical Tillage Tool To Control Weeds In Row-Crop Production Systems, Grace Mccormick Friday

Theses and Dissertations

Weed control is an integral part of a successful overall production strategy in row- cropping systems and has the potential to reduce or eliminate yield losses that negatively affect profitability. Timely and correctly selected herbicide applications are the major keys for effective weed control in a majority of instances. However, there are negative factors that contribute to ineffectiveness and weed escape issues that currently lack viable options for management. Sparsely populated late-season weeds that emerge after lay-by herbicide applications and weeds that have become tolerant and resistant to traditional herbicide chemistries are of greatest concern. Historically, these weeds would have …

Physiological And Yield Responses Of Soybean Cultivars To Heat And Drought Stresses, Sadikshya Poudel

Theses and Dissertations

Soybean (Glycine max L.) is an important legume crop often exposed to heat and drought stresses during reproductive and early-seed setting stages, resulting in lower yields and seed quality. Ten soybean cultivars were phenotyped for individual (drought or heat) and combined stress tolerance. Under drought, reduced stomatal conductance and increased canopy temperature significantly reduced seed number (46%) and weight (35%). Heat stress alone reduced seed number (19%) and weight (23%) compared to control. Moreover, a degree increase in daytime temperature above 32 °C during the reproductive stage reduced seed weight by 4% and 7% under well-watered and drought conditions, respectively. …

Managing Iron Deficiency Chlorosis (Idc) In Soybean Through A Cropping System Approach, Katelin Savannah Waldrep

Theses and Dissertations

Iron deficiency chlorosis (IDC) is a frequent problem throughout many areas of the United States where soils are high in calcium carbonate (CaCO₃), including the Blackland Prairie regions of Mississippi. The main objectives of this study were to 1) determine the effects of seven different cropping systems on IDC visual symptomology and grain yield in rainfed soybeans grown in calcareous soils, and 2) evaluate the effects of soil water tension (SWT) on IDC. Rotating soybeans with corn produced significantly higher yields for both tolerant and susceptible soybean varieties. IDC symptomology was worse, and yields were lower in cropping …

Evaluation Of Early Maturing Cultivars, Optimal Harvest Timing, And Canopy Reflectance Of Peanut To Maximize Grade And Yield, Joseph Bryan Whittenton

Theses and Dissertations

Peanut digging timing is difficult to predict due to indeterminate growth and peanut pods maturing underground, resulting in the need to research methods that provide consistent measurements, while reducing time and effort for farmers and researchers. Experiments were conducted to evaluate the accuracy of the Maturity Index 1 and Maturity Index 2 in predicting peanut grade, the accuracy of the North Carolina 2 degree day method in predicting peanut yield, and remote sensing vegetative indices sensitivity equivalence (SEq) to peanut Maturity Index 2 and harvest grade (TSMK) for cultivars IPG-914 and Georgia-06G in Mississippi.

Maturity Index 1 and …

Long-Term Conservation And Conventional Tillage Systems Impact Physical And Biochemical Soil Health Indicators In A Corn–Soybean Rotation, Anuoluwa O. Sangotayo, Jemila Chellappa, Udayakumar Sekaran, Sangeeta Bansal, Padma Angmo, Paul J. Jasa, Sandeep Kumar, Javed Iqbal

Department of Agronomy and Horticulture: Faculty Publications

Agricultural management practices tend to influence soil structure stabilization, mediating many physical, chemical, and biological processes in soils. Therefore, understanding the long-term effects of management practices on various soil health indicators is crucial to develop sustainable agricultural practices. This study aimed to assess the long-term conventional and conservation tillage effects on soil physical (aggregates) and biochemical (soil organic carbon [SOC], enzymes, and microbial biomass) parameters under a range of tillage practices in a corn–soybean rotation in Nebraska. The experiment was conducted at two locations as follows: (1) Concord site (36 years) with the three treatments: no-till (NT), disk, and moldboard …

Soil Respiration Measurements Reveal High Retention Of Organic Carbon From Corn Residue Derived High-Lignin Fermentation Byproduct Enabling Sustainable Lignocellulosic Biofuel Production, Michelle Sun Wang

Dartmouth College Master’s Theses

While 2G biofuel production can utilize non-edible, lignocellulosic feedstocks such as agricultural residues to produce liquid fuel, harvesting crop residues is unsustainable without careful management of the soil underneath. By harvesting a fraction of the crop residues left in the field after harvest, soil health can diminish and critically, the soil organic carbon (SOC) stored in agricultural fields can decrease. Currently, in the most popular 2G process models published, the issue of soil degradation remains unresolved with residue harvest strategies receiving considerable attention in the literature and other SOC management strategies receiving far less. Specifically, the strategy of returning the …

Hybrid Allele‑Specific Chip‑Seq Analysis Identifies Variation In Brassinosteroid‑Responsive Transcription Factor Binding Linked To Traits In Maize, Thomas Hartwig, Michael Banf, Gisele Passaia Prietsch, Jia‑Ying Zhu, Isabel Mora‑Ramírez, Jos H. M. Schippers, Samantha J. Snodgrass, Arun S. Seetharam, Bruno Huettel, Judith M. Kolkman, Jiashi Yang, Julia Engelhorn, Zhi‑Yong Wang

Department of Agronomy and Horticulture: Faculty Publications

Background: Genetic variation in regulatory sequences that alter transcription factor (TF) binding is a major cause of phenotypic diversity. Brassinosteroid is a growth hormone that has major effects on plant phenotypes. Genetic variation in brassinosteroidresponsive cis-elements likely contributes to trait variation. Pinpointing such regulatory variations and quantitative genomic analysis of the variation in TF-target binding, however, remains challenging. How variation in transcriptional targets of signaling pathways such as the brassinosteroid pathway contributes to phenotypic variation is an important question to be investigated with innovative approaches.

Results: Here, we use a hybrid allele-specific chromatin binding sequencing (HASChseq) approach and …

Economic Analysis Of Western Corn Rootworm Injury To Continuous Corn In Northeast Nebraska, Isadora Vercesi Bethlem

Department of Agricultural Economics: Dissertations, Theses, and Student Research

The most economically significant corn pest in the US Corn Belt is the Western Corn Rootworm (WCR), Diabrotica virgifera virgifera LeConte. This study compares a field experiment outcome of 4 different treatments against WCR, which consist of a rootworm Bt corn pyramid (SmartStax®) and non-rootworm Bt trait hybrid (VT2P), with or without the addition of the rootworm soil insecticide (Aztec®) to identify the risk-reward trade-off for each one of them. Observed prices were used for the years in the study (2020, 2021, and 2022), and low and high price scenarios were simulated for the period, to incorporate different dynamic relations …

Hymenachne Amplexicaluis [(Rudge) Nees] Genetic Resources Collection In México, A Suitable Grass For Flood Plains In Tropical Areas, J. F. Enriquez-Quiroz, A. R. Quero-Carrillo, J. Perez-Perez, A. Hernandez-Garay, E. Garcia-Moya

IGC Proceedings (1977-2023)

Hymenachne amplexicaluis [( Rudge ) Nees; 2n= 2x= 24; Azuche, West Indian marsh grass] is a native Central and South America C₃ grass that grows well under intermittent flooding conditions. It produces good seed set and stolons to thrive on new areas assuring its survival, combined with an efficient N metabolism to promote vigorous new growing leaves and tillers (Antel et al., 1998). Azuche is a dual attribute species when introduced to new areas; it has valuable forage attributes but also is a potential weed (Hill, 2000). As Azuche is a native species, one must deal with in …

Critical Analysis Of Tropical Forage Breeding In Brazil, J. A. Usberti Jr., P. B. Alcantara

IGC Proceedings (1977-2023)

Forage grasses account for 90% of the Brazilian forage seed market while the genera Brachiaria, Panicum and others are responsible for 85, 10 and 5% of the traded grass seeds, respectively. Most of the forage grass and legume cultivars available for sowing in Brazil were selected in germplasm banks during the last 20 years, while few of them were derived from artificial crossings, followed by selection for desirable forage traits. The selection of new genetic materials in germplasm banks (exploitation of naturally-occurring genetic variability) is still feasible but the chances of success are decreasing through time. From now on, …

Economic Contribution Of The Agricultural Sector To The Arkansas Economy In 2021, Leah English, Jennie Popp

AAES Research Reports and Research Bulletins

Agriculture and associated agricultural activities are major contributors to the Arkansas economy. Agriculture is defined as the sum of agricultural production and processing activities, unless otherwise specified, and includes crop and animal production and processing, agricultural support industries, forestry and forest products, and textile goods. Agriculture contributes to the economy through direct agricultural production and processing, leading to economic activity in other parts of the economy.

This report is the sixteenth in a series that examines agriculture’s economic contribution to the Arkansas economy. The total economic contribution of agriculture (direct, indirect, and induced effects) on value added, employment, and labor …

Protecting Wa Crops Issue 30 - May 2023, Department Of Primary Industries And Regional Development, Western Australia

Protecting WA Crops

Protecting WA Crops Issue 30 - May 2023 contents:

• GRDC Perth Research Updates – Pathology – Part 2
• Impact of fungicide product, rotation and timing on Net form net blotch in Planet barley in southern WA
• Economical management of Spot form net blotch in low rainfall environments
• Meet crop protection team member – Jason Bradley

Effects Of Exercise When Transitioning From Free Choice Tall Fescue (Lolium Arundinaceum) Grass Diet In Late Summer To Free Choice Tall Fescue Hay Diet In Late Fall On Plasma Fructosamine Concentrations, Insulin Levels, Body Weight, And Body Condition Scores Of Stock Horse Mares And Gelding, Riley Brown

Masters Theses & Specialist Projects

Equine exercise may influence a horse’s metabolic and physiological functions. Studies can help to prove this linkage, and to better understand the nutritional requirements of the horse. The parameters that are being evaluated are plasma-fructosamine concentrations, insulin levels, body weight (lbs.), and body condition score (BCS) as a measurement of obesity. Eight horses used in this study were split into two groups; Worked horses were exercised three times a week while the unworked horses were not exercised. All eight horses were fed an ad libitum diet of tall fescue grass and hay for 127 days.

Forage samples were collected to …

Winter Cover Crop Performance In The Southern Piedmont Region Of South Carolina, Payton Davis

All Theses

Cover crops (CC) offer in-field and environmental benefits when integrated into cropping systems. Low CC adoption in the southern Piedmont of South Carolina is partially due to the lack of information on CC performance and benefits within the region. To address this, eight winter CC and a fallow/pigweed treatment were investigated for their influence on soil temperature, volumetric water content (VWC), percent cover, biomass, and the occurrence of soil water repellency (SWR). A randomized complete block design experiment was conducted in the fall and winter of 2021-2022 (EXP A) and repeated in 2022-2023 (EXP B). Cover crops minimally influenced soil …

Pestfacts Wa Issue 03 - May 2023, Cindy L. Webster, Svetlana Micic, Alan Lord, Andrea Hills, Jean Galloway, Rebecca Severtson

PestFacts WA

PestFacts WA Issue 3 - May 2023 contents:

• Identifying weevils
• Downy mildew in canola
• Meet PestFacts WA team member, Bec Severtson

Pestfacts Wa Issue 05 - May 2023, Benjamin S. Congdon, Cindy L. Webster, Ciara Beard, Geoff J. Thomas

PestFacts WA

PestFacts WA Issue 5 - May 2023 contents:

• Early season aphid and virus risk in cereals and canola
• Black and white tiger moth caterpillars
• Lupinosis risk this season

Precision Management Of Inputs In Cotton And Soybean Production In South Carolina, Kyle Smith

All Theses

The adoption of precision agriculture technologies and developing specific product use recommendations in cotton and soybean production could help farmers reduce input costs and optimize overall farm profitability. The objectives of this research were to evaluate whether or not the use of variable rate seeding in cotton could increase profitability and to determine the rainfast interval of commonly used insecticides in cotton and soybean production. The first trial, variable rate seeding in cotton, was implemented at the Edisto Research and Education Center near Blackville, SC across five years to evaluate variable rate seeding in cotton. Results from trials in South …

Influence Of Potassium Fertilizer Application Timing On Cotton Production As Related To Soil Potassium On U.S. Coastal Plain Soils, Shruthy Suresh Kumar

All Theses

Understanding soil K dynamics is highly significant in cotton production owing to its prominent role in cotton fiber quality. About 31 % of cotton production in the U.S. is concentrated in SE states, with coastal plain soils having low innate K availability. Crop fertilizer-K recommendations are primarily made worldwide and across the U.S. using pre-plant STK concentrations. A literature review on cotton K studies suggests that fertilizer-K recommendations based on pre-plant STK concentrations alone need fine-tuning to meet the increasing K demands in modern cultivars, variations in crop K requirement patterns, and varied soil K supplying capacity. Studies have been …

Evaluating Planting Green And Herbicides For Integrated Weed Management And Their Effect On Soil Properties In Corn And Soybean In Nebraska, Trey Parker Stephens

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

Producers across the Midwest are finding new ways to implement cover crops into cropping systems and the practice of “Planting Green” is one of the newest uses of cover crops. When planting green, producers plant their row crops into actively growing cover crops and terminate the cover crop at time of planting or shortly after planting. This practice would allow for higher biomass accumulation of the cover crop and could aid in weed management of herbicide-resistant weeds. The objective of the first two studies was to evaluate planting green and its effect on soil-applied residual herbicides, weed management, dicamba/glyphosate-resistant soybean …

Genomic Selection For Yield And Seed Composition Stability In An Applied Soybean Breeding Program, Benjamin Mark Harms

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

Stability traits are of primary importance in plant breeding to ensure consistency in phenotype across a range of environments. However, selection efficiency and accuracy for stability traits can be hindered due to the requirement of obtaining phenotype data across multiple years and environments for proper stability analysis. Genomic selection is a method that allows prediction of a phenotype prior to observation in the field using genome-wide marker data and phenotype data from a training population. To assess prediction of stability traits, two elite-yielding soybean populations developed three years apart in the same breeding program were used. The individuals in each …