Life Sciences Commons^™

Multi-Tactic Ecological Weed Management In A Changing Climate, Sonja K. Birthisel

Electronic Theses and Dissertations

Climate change is expected to impact weed communities in Maine, and the efficacy of tools and tactics farmers use to manage them. Through seedbank sampling and surveys of Maine organic farms, we identified currently rare weeds that are known to be especially abundant or problematic in warmer areas of the USA and might therefore represent an emerging agronomic risk. Many ecological weed management strategies that focus on depleting the weed seedbank are expected to remain effective in a changing climate, and become increasingly important as efficacy of cultivation and some herbicide applications diminish or become more variable. Through field experiments, …

Flower Visitation In Relation To Pollen And Nectar Nutrition: Implications For Pollinator Habitat And Conservation, Megan E. Leach

Electronic Theses and Dissertations

Pollination of both wild and crop plants is at a crossroads; honey bee populations are experiencing losses at a higher rate than ever before, and some native bee species are declining in abundance to the point of being listed as endangered species. A few examples of these threats include pesticide exposure, habitat loss, and climate change. In response to bee population declines, conservation efforts have been initiated to increase habitat quality for bees by planting pollinator reservoirs or gardens. Plants provide nutrition to bees in the form of pollen and nectar. Several studies have shown links between higher nutritional quality …

Band-Sowing With Hoeing For Weed Management In Organic Grains, Margaret R. Mccollough

Electronic Theses and Dissertations

Weeds remain the foremost production challenge for organic small grain growers in the Northeastern United States. Instead of sowing crops in narrow, single-line rows, band-sowing with inter-band hoeing is a cropping strategy that could provide superior weed control. In theory, band-sowing suppresses weeds in the intra-band zone by improving the spatial arrangement of the crop from that of typical rows to a more uniform pattern within the planted bands, maximizing interspecific and reducing intraspecific competition. Weeds in the inter-band zone are controlled by cultivating with aggressive sweeps; tine harrowing can target weeds in the intra- and inter-band zones.

Chapter one …

Student Athlete Retention And Performance In Agriculture: An Analysis Of A Mentorship Program, Nick Cates

Electronic Theses and Dissertations

This qualitative research study focuses on the effectiveness of the athletic academic mentoring and advising program at Stephen F. Austin State University and its potential to replicate a similar program in the agriculture program. With emphasis on increasing the effectiveness of the current mentoring program, increasing student retention in agriculture, and improving the transition for high school students going into college, this study utilizes a questionnaire comprised of seven questions to determine how 14 former and current student-athletes that were enrolled in agriculture felt about the mentoring program and agriculture department. Many of the challenges faced by students, such as …

Optimizing Fertilizer And Compost Rates In Organic Reduced Till Agriculture, Nicholas W. Rowley

Electronic Theses and Dissertations

Interest in reduced tillage systems has been increasing and advanced by a need to practice agriculture in a sustainable way to limit environmental degradation. The focus on preserving soil integrity has become commonplace in all scales of agriculture. Recently trends in agricultural production have given rise to numerous small farms centered on local and sustainable farming. In turn, this has led to a growing desire to implement conservation tillage into these systems.

In 2015 and 2016 a collaborative effort between the University of Maine at the Maine Agricultural and Forestry Experiment Station: Highmoor Farm and Cornell University at the Homer …

Reducing Tillage In Small-Scale Permanent Bed Organic Vegetable Production Systems, Jeremiah D. Vallotton

Electronic Theses and Dissertations

The response of field-grown vegetable crops to reduced tillage and mulching in permanent beds was evaluated through measuring crop yields, weed pressure, earthworm counts, and soil basal respiration. Two vegetable crops (“Bush Delicata” squash and “Farao” cabbage) were started in April and May of 2016 and 2017 respectively, transplanted in late June, and harvested on 15-Sep-2016 and 25-Aug-2017. Fruit number and weight of squash, and head weight and feeding damage of cabbage were measured. These results suggest that intensive tillage (8” rototill every year) can be successfully reduced to alternating years of shallow (2”) rototilling and a less intensive form …

T Socio-Ecology Of Managed Honeybees (Apis Mellifera) In The Louisville Metro Area., Haileigh M. Arnold

Electronic Theses and Dissertations

Humans have a long history of the practice of beekeeping to harness the power of pollination. This managed pollinator system consists of beekeepers, honeybees, and their environment. However, recent disease, pesticide use, and land use factors honeybee threaten this relationship. In the face of such concerns it is important to examine the factors that impact and can help sustain our managed pollinator systems. In this thesis, the national and Kentucky state-level policies that affect managed pollinator systems were examined and socio-ecological factors that may contribute to honeybee hive growth and losses were assessed along an urban development gradient in Louisville, …

Tripartite Interactions Of Legumes With Arbuscular Mycorrhizal Fungi And Rhizobial Bacteria: Insight Into Plant Growth, Seed Yield, And Resource Exchange, Arjun Kafle

Electronic Theses and Dissertations

Under natural conditions, legumes, such as alfalfa (Medicago) and soybean (Glycine max) are colonized with arbuscular mycorrhizal (AM) fungi and rhizobial bacteria forming tripartite interactions. Legumes are important crop species due to their high nutritional and economic values. Most of the previous literatures focused on experiments with an individual symbiont: either AM fungi or rhizobial bacteria, but not with both symbionts at the same time, thus our current understanding of resource exchange in tripartite interactions is limited. It has been reported that AM fungi primarily provide phosphate (P), nitrogen (N), and other nutritional and non-nutritional benefits while rhizobial bacteria solely …

Development Of Vegetation Mapping With Deep Convolutional Neural Network, Sae-Han Suh

Electronic Theses and Dissertations

The Precision Agriculture plays a crucial part in the agricultural industry about improving the decision-making process. It aims to optimally allocate the resources to maintain the sustainable productivity of farmland and reduce the use of chemical compounds. [17] However, the on-site inspection of vegetations often falls to researchers’ trained eye and experience, when it deals with the identification of the non-crop vegetations. Deep Convolution Neural Network (CNN) can be deployed to mitigate the cost of manual classification. Although CNN outperforms the other traditional classifiers, such as Support Vector Machine, it is still in question whether CNN can be deployable in …

Quantifying The Short-Term Impacts Of Cover Crops And Grazing On Soil Health Under An Integrated Crop-Livestock System In South Dakota, Vishal Seth

Electronic Theses and Dissertations

Cover crops and grazing under Integrated Crop-Livestock System (ICLS) can impact the rhizosphere nutrient cycling and may have potential to increase the long-term sustainability and economic profitability of agricultural production system. In South Dakota, crop production practices and livestock husbandry are both common which provide the opportunity for ICLS to be successful in this region. However, little is known about the impacts of the cover crops and grazing under ICLS on soil properties in this region. The present study was conducted at South Dakota State University Research Farm (44°20'34.8"N, 96°48'14.8"W), Brookings, SD, to quantify the impacts of cover crops and …

Air-Propelled Organic Fertilizer Grits Can Be Used To Control Weeds And Provide Nitrogen, Michael Carlson

Electronic Theses and Dissertations

Weeds are one of the biggest challenges for organic growers because of the alternative weed control methods. Air-propelled abrasive grit management has been reported to control weed seedlings in corn and soybeans while maintaining yield. This research examined the weed control, corn and soybean yields, nitrogen mineralization, and nitrogen yield responses from grits. The grits used in this research included: Phytaboost Plant Food 7-1-2 (soybean meal), Sustane 8-2-4 and 4-6-4 (turkey litters), and two non-fertilizer grits: Agra Grit (walnut shells) and corn cob meal. Field studies were conducted from 2015 to 2017 in Aurora, SD, Beresford, SD and Morris, MN. …

Efficiency Of Utilizing Standardized Ileal Digestible Lys And Thr For Whole Body Protein Retention In Pregnant Gilts During Early, Mid And Late Gestation, Ron Aldwin Sapin Navales

Electronic Theses and Dissertations

In pregnant pigs, amino acid (AA) requirements represent the sum of those required for maintenance functions, protein retention and efficiency of utilizing AA intake for the aforementioned body processes. The NRC (2012) model assumed AA efficiency is constant across period of gestation; however this is not reflective of the changes in metabolic demand during gestation. Therefore, two experiments were conducted to evaluate the efficiency of utilizing SID Lys and Thr for whole body protein retention (kSIDLys and kSIDThr) in pregnant gilts during early, mid and late gestation. Three 12 d N-balance studies were conducted to represent different periods of gestation. …

Effects Of Standards-Based Grading On Students In Agricultural Education, Matthew Tripp

Electronic Theses and Dissertations

Standards-based grading is being discussed more frequently in the field of education as school districts either explore or adopt this grading method. This study examined the effects of standards-based grading on achievement and perceptions of students enrolled in high school agricultural education courses. This nonequivalent quasi-experimental study focused on how students’ perceptions of classroom feedback, abilities, and opportunities to redo assessments were affected by the implementation of a standards-based grading method. Participants in this study were students who enrolled in a quarter long Home Maintenance course that used standards-based grading methods to assess student mastery on specific content standards in …

A Quantitative Environmental Assessment Of Incorporating Torrefaction Into Farming Enterprises In Eastern South Dakota, Dinesh Fuyal

Electronic Theses and Dissertations

The use of renewable energy sources has been increasing in the recent years due to population growth and environmental concerns. Biomass is a promising energy source that can be used to produce biofuels or torrefied pellets. Torrefied biomass may be used in power plants, industrial and residential heating, feedstocks for gasification, air and water filtrating, and soil amendment. The interest of torrefied pellets as energy sources for various applications has been increased in the recent years due to the concerns about energy security and environmental issues. This study focuses on the economic and environmental assessment of agricultural feedstocks like corn …

Regulation Of Local Auxin Metabolism During Soybean Nodule Development, Suresh Damodaran

Electronic Theses and Dissertations

Legume-rhizobia symbiosis leads to the development of secondary root organs called nodules. Rhizobia bacteria housed inside nodules assimilate atmospheric nitrogen and convert them into plant usable forms thereby reducing the need for fertilizer application in crop legumes like soybean. Nodule development is a coordinated process orchestrated by multiple plant hormones. In soybean, the auxin responsive gene expression was detected in nodule primordia and in the periphery of mature nodules, primarily in nodule vasculature. Auxin hypersensitivity reduces nodule formation in soybean and also polar auxin transport inhibition at the site of nodule development is not crucial for determinate nodule formation. Therefore, …

Insecticidal Seed And In-Furrow Treatment Recommendations For Soybean And Sunflower, Brady Hauswedell

Electronic Theses and Dissertations

Throughout the 2016 and 2017 growing season, field research experiments were replicated across South Dakota. Many times seed treatments are used prophylactic, which is neither good for the producers or the environment. Producers will be able to reduce production costs, if they only use a seed treatment when necessary. The purpose of the first experiment was to determine the effects of seed treatments in combination with planting date and seeding rate on soybean yield. To determine the effects, two years of field data from four eastern South Dakota locations were compared. Within each year and location we compared two planting …

Can Solvent-Or Mechanically-Extracted Carinata Meal Be Used As An Effective Source Of Supplemental Protein To Cows Fed Poor Quality Forages?, Emily Jacklyn Rosenthal

Electronic Theses and Dissertations

Brassica carinata is an oilseed crop that requires a relatively short growing season and produces high crop yields. It is a great source for aviation biofuel, however it produces a large amount of waste that may be used as a protein supplement for cattle. We tested the effects of solvent- or mechanically-extracted carinata meal as a protein supplement to ad libitum ground or long-stem corn residue (i.e., corn plant left over from grain harvest) had on cow performance and digestibility. Fifty-six non-pregnant cows in 8 pens had ad libitum access to either long-stem or ground corn residue in addition to …

Rebuilt And Remade: The Florida Citrus Industry, 1909-1939, James Padgett

Electronic Theses and Dissertations

Prior to orange juice concentrate, Florida citrus was already an industrialized agricultural sector. This thesis explores the early-20th-century Florida citrus industry and demonstrates that contemporary farming practices were influential in advancing how citrus was produced, processed, worked, marketed, and regulated in early-20th-century Florida. Restarted after devastating freezes in 1894-1895, resolute Florida growers rebuilt their groves into marvels of large-scale citrus fruit production. Continuing a legacy in experimental crossbreeding, improved varieties of citrus were developed to lengthen the season and markets. Advocated by nurserymen and university educators, biological innovation helped the citrus thrive in the 1910s and 1920s from adverse weather …

Evaluation Of Dietary Phytochemicals As Rumen Modifiers In Lactating Dairy Cows, Sonia Rodriguez Jimenez

Electronic Theses and Dissertations

Phytochemicals such as tannins included in dairy cow nutritional programs, as a natural feed additive, promise to improve rumen bypass protein and consequently reduce the feeding cost by decreasing the amount of CP needed in the ration. Additionally, if tannins are fed along with high quality protein sources, this could improve the AA profile reaching the small intestine and potentially improving health and performance of dairy cows. The black pepper, specifically its alkaloid piperine, is a nontoxic, natural dietary compound with a broad range of physiological activity. Lactating dairy cows ingesting these phytochemicals (tannin extracts and black pepper) will potentially …

Impacts Of Diverse Crop Rotations And Integrated Crop-Livestock System On Soil Quality In South Dakota, Atilla Polat

Electronic Theses and Dissertations

Crop diversification can be beneficial in improving soil quality parameters. Diverse crop rotations and integrated crop-livestock systems (ICLS), are two examples of crop diversification used in this study to assess soil quality. The objectives of this study were to: (i) assess the impacts of diverse rotations on soil quality parameters, and (ii) assess the impacts of low and high stocking density on soil quality parameters. Both of the studies were conducted separately and are presented as two different chapters. To accomplish objective (i), a long-term experiment was selected which was established near Brookings, South Dakota, USA at USDA-ARS lab in …

Adoption Of Conservation Practices And Precision Technologies In South Dakota: An Empirical Analysis, Allen P. Deutz

Electronic Theses and Dissertations

Advances in conservation agriculture and precision agriculture technology practices have contributed to the adoption of conservation practices that reduce externalities from agricultural production, but this conversion was usually coupled with economic incentive, whether from increases in fertility and yield, or payments for on farm retirement or restoration practices. This study expands on this theme, evaluating the connection between conservation and the increased use of various precision agriculture technologies. The study uses survey data collected from South Dakota farmers and ranchers, with responses from 28 counties and over 500,000 acres of crop, pasture, and range land to address the following three …

Measuring The Influence Of Bedding On Soil Nitrogen Losses And Corn Crop Nitrogen Characteristics For Fall Applied Solid Beef Cattle Manure In Eastern South Dakota, Mukesh Mehata

Electronic Theses and Dissertations

Nitrogen (N) is a major component of chlorophyll which plays a key role in the photosynthesis process in crops. The N is one of the highest demanded nutrients by all plants for their growth and reproduction. Manure or inorganic fertilizer is often applied to fulfill the crops’ N demand. However, the applied N sources have the potential of N losses in different forms from the soil volume in many ways such as ammonia (NH₃) volatilization, aerial nitrous oxide (N₂O) loss, nitrate (NO₃ --N) leaching, and runoff and/or erosion. Soil fertility, crop yield, water quality, and …

Land Use Change Sustainability And Carbon Turnover Rate In The Northern Great Plains Soil, Deepak Raj Joshi

Electronic Theses and Dissertations

Sustainable land management involves the management of land, water, biodiversity and other resources that meet human requirements while maintaining ecosystem services. In the northern Great Plains (NGP), the combined impacts of landuse and climate variability have placed many soils at the tipping point of sustainability. The objectives of this study were to: 1) calculate land-use changes from 2006 to 2012 and from 2012 to 2014 in South Dakota and Nebraska; 2) assess if land use changes had impacted on soil sustainability; 3) calculate variation in total carbon budget and turnover due to seasonal climate variability, biomass quality and soil properties; …