Agriculture Commons^™

Effects Of Wilting Extent On The Phytoestrogen Levels, Nutritional Value, Microbial Populations, And In Vitro Ruminal Methane Emissions Of Red Clover Hay And Silage Across Stages, Diego Zamudio Ayala

Electronic Theses and Dissertations

The main objective of this thesis is to improve the understanding and awareness of methodologies to decrease phytoestrogens in conserved legumes without sacrificing forage nutritive value. In chapter 1, we discussed the main factors influencing each stage of hay production and our current understanding of the hay microbiome dynamics. The primary objective of haymaking is to dry forage enough (80-85% DM) to inhibit the growth of undesirable microbes and halt residual plant enzymatic activity that causes nutrient losses. During the field and storage phases of haymaking, the environment, management practices, and other factors influence the extent of DM losses. This …

The Influence Of Framing And Recent Experience On Farmer Choices In Experimental Games Depicting Risk-Reducing Agricultural Technologies, Ana Maria Ospina Tobar

Electronic Theses and Dissertations

Climate change is a major threat to food security, particularly in low and middle-income countries that are highly dependent on staple crops for subsistence. The vulnerability of staple crops, like maize, in the face of climate change, is increasing due to the increasing frequency of droughts. This thesis aims to evaluate two mechanisms through which farmers may be more willing to adopt new technologies that increase their resilience to climate change: First, I evaluate the effectiveness of a new virtual maize farming game as a learning tool to teach farmers about the outcomes they could obtain under different weather events …

Quantifying Spatial Heterogeneity Of Wild Blueberries And Crop Water Stress Monitoring Using Remote Sensing Technologies, Kallol Barai

Electronic Theses and Dissertations

The wild blueberry is one of the major crops of Maine, with significant economic value and potential health benefits. Due to global climate change, drought impacts have been increasing significantly in recent years in the northeast region of the USA, causing significant economic losses in the agricultural sectors. It has been predicted to increase further in the future. Changing patterns of the elevated atmospheric temperatures, increased rainfall variabilities, and more frequent drought events have made the wild blueberry industry of Maine vulnerable, suggesting the adoption of novel approaches to mitigate the negative impacts of global climate changes. Also, wild blueberry …

Weaving An Interdisciplinary Microbiome Career Using Threads From Different Ecosystems, Sarah Hosler

Electronic Theses and Dissertations

Animals have trillions of microorganisms living in or on many body sites, these communities of microorganisms are called microbiomes. Microbiomes are typically host-specific, and a lot of information about the host can be determined from investigating them. Microbiome research has many real-world applications, and this thesis utilizes the One Health perspective, which acknowledges the connection of humans, animals, and environments, and emphasizes the need for collaborative, interdisciplinary research. The first interdisciplinary project is an investigation into the bacteria in wild and cultured Atlantic deep-sea scallop, Placopecten magellanicus larvae. Adults in hatcheries can be induced to spawn, but the last two …

Assessment Of Historical Climate Variability In Maine With Implications For Future Agricultural Productivity And Adaptation, Carly Frank

Electronic Theses and Dissertations

Climate change is a wicked problem with global impacts, one of which being the sustainability of the existing global food system. As temperatures and variability in precipitation are projected to increase, the challenges to agriculture are expected to intensify. This thesis examines the Maine historical climate record over the growing season, in combination with future projections, to assess how conditions have changed and will change with agricultural implications. In this analysis, relevant climatic variables are analyzed, and agriculture-significant measures are derived for Maine’s three climate divisions using four decades of daily and monthly gridded datasets. In addition, this thesis explores …

Adaptation Strategies For Wild Blueberry Growers In A Changing Climate: Mulching Effects On Crop Productivity And Fertility Effects On Blueberry Gall Midge, Rebecca Gumbrewicz

Electronic Theses and Dissertations

Wild blueberry (Vaccinium angustifolium Aiton.) cropping systems are considered resilient to environmental changes due to ecological and genetic diversity within each field. However, wild blueberries can be sensitive to weather fluctuations that cause extreme temperature or moisture regimes. Climate change in Maine is represented by increasing rates of warming temperatures, more intense precipitation events, and more frequent atmospheric “blocking” patterns. Warming temperatures result in the northward expansion of pest ranges and altered growing seasons. More extreme rainfall events lead to damaged plantings and soil erosion. Atmospheric blocking leads to an increased likelihood of heat waves and drought. Two experiments were …

To Know The Land With Hands And Minds: Negotiating Agricultural Knowledge In Late-Nineteenth-Century New England And Westphalia, Justus Hillebrand

Electronic Theses and Dissertations

Ever since the eighteenth century, experts have tried to tell farmers how to farm. The agricultural enlightenment in Europe marked the beginning of a long arc of new experts aiming to change agricultural knowledge and practice. This dissertation analyzes the pivotal period in the late nineteenth and early twentieth century in Germany and the United States when scientists, improvers, and market agents began to develop comprehensive ways to communicate agricultural innovation to farmers. In a functional approach to analyzing the negotiation of agricultural knowledge through its communication in things, words, and practices, this dissertation argues that the process of change …

Expanding Our Understanding On Feed Spoilage And Developing Novel Approaches For Its Mitigation, Marjorie A. Killerby

Electronic Theses and Dissertations

The main objective of this study is to improve the understanding and awareness of conserved feed spoilage and to develop novel technologies that can prevent it. In chapter 1, we conducted a meta-analysis to evaluate the effects of chemical (50 articles)and biological (21 articles)preservatives on hay spoilage during storage. Multi-level linear mixed-effects modelswere fit including moderators:Preservative Class (PC), forage type (FT); moisture class (MC), and application rate (AR). Dry matter (DM) loss was affected by PC×FT (P=0.045), PC×AR (P<0.001), and PC×MC (P=0.009),relative to the overall effect of preservatives (-0.37% units). DM loss in propionic acid (PropA)-treated hay was numerically reduced to a greater extent in grasses (-16.2), followed by mixed hay (-1.76), but it was actually increased (+2.2%)in legume hay.Increasing ARof PropA resulted in decrease in DM loss (β = -1.34).Application ofBuffered Organic Acids,Other Organic Acids, PropA,and Anhydrous Ammoniadecreased visual moldiness by -22.1, -29.4, -45.5 and -12.2% units, respectively (PC; P<0.001). Sugars increased in treated grass hay (+1.9) and decreased in treated legume hay -0.8% DM, respectively (P<0.001). Microbial inoculants had small effects on hay spoilage since the overall DM loss effect size was - 0.21%. Inoculated grass hay preserved moresugars (+1.47) than treated legume hay (+0.33) relative to untreated hay (x=4.63% DM; P<0.001). In conclusion, organic acid-based preservatives effectively prevent spoilage of hay as influenced by FT, MC and AR, but microbial inoculants had only small effects. In chapter 2, we evaluated the effects of chemical and biological preservatives and ensiling stage on spoilage, ruminal in vitro fermentation, and methane production of wet brewer’s grain (WBG) silage. Treatments (TRT) were sodium lignosulfonate at10 g/kg (NaL1) and 20 g/kg (NaL2; fresh WBG), propionic acid at 5 g/kg fresh WBG (PRP, 99%), a combination inoculant (INO; Lactococcus lactisand Lactobacillus buchneri each at 4.9 log cfu/fresh WBG g), and untreated (CON). Three stages (STG) were tested:treated WBG (Fresh) was ensiled for 60 d(Ensiled), after which they were opened and aerobically exposed for 10 d (AES). Data were analyzed as a RCBD (5 blocks) with a 5 TRT × 3 STG(Fresh, Ensiled and AES) factorial arrangement. Our results show that Ensiled PRP-treated WBG markedly preserved more sugars (250) and starch (190) than all other Ensiled TRT (x=136 ± 16.2sugarsg/kg DM and x=121 ± 6.15 starch g/kg DM, respectively; P<0.001). Due to its superior nutritive value, PRP-treated AES was less aerobically stable than CON (61.9 vs. 90.1 h; P = 0.03). Preservation was not improved by INO, NaL1 or NaL2, but the latter prevented the increase of neutral detergent fiber (NDF)across STG (x=384).In vitro ruminal fermentation of Fresh WBG resulted in higher methane concentration (0.94) and yield (0.27) than theother STG (x=0.84 ± 0.07mMand x=0.23 ± 0.03mmol/g fermented OM, respectively). In conclusion, PRP was the most effective at preserving WBG during ensiling but failed to improve aerobic stability. In chapter 3, we evaluated the effects of application rate (AR) of sodium lignosulfonate (NaL) and propionic acid(PRP)on high moisture alfalfa hay spoilage during storage and its nutritive value. Treatments (TRT; NaL and PRP) were applied at four AR: 0 (CON), 2.5, 5 and 10 g/kg (fresh basis) to alfalfa hay at 68.5% DM, packed into mini balesand stored for 33 d.Data were analyzed as a RCBD(5 blocks) with a 2 TRT x 4 AR factorial arrangement. At d 33, DM losses were decreased by PRP at 5 and 10 g/kg (0.9), vs.CON (6.92) andNaL (6.63 ± 1.13%). Visual moldiness (0-10) and mold counts were also decreased by PRP at 5 (2.4 and 5.30) and 10 g/kg (0 and 2.7) relative to CON (6.0 and 7.13) and NaL (5.85 ± 0.67 and 7.21 ± 0.31 log cfu/fresh g, respectively). Both TRT increased apparent in vitroDM digestibility at all AR relative to CON (x=543 vs 501 ± 12.0g/kgof DM, respectively), but the acetate-to-propionate ratio was higher for NaL at 10 g/kg (3.02) vs. CON (2.89 ± 0.04). In conclusion, NaL failed to prevent spoilage of high moisture alfalfa hay while PRP was effective at doses >5 g/kg. Both TRT at 10 g/kg improved the rumen in vitro fermentation measures of high moisture alfalfa hay but PRP …

Evaluating Methods For Research In Physical Weed Control And Farm Asset Tracking, Johnny J. Sanchez

Electronic Theses and Dissertations

Effective weed control has long been recognized as critical for agricultural production, yet weeds remain a major constraint to production and economic return in many agroecosystems. Moreover, improvements in physical weed control are necessary to address increasing problems of herbicide resistance in weeds of grain and fiber crops and the high cost of hand weeding in vegetables. From tractor-mounted cultivation tools to autonomous weeders, weeding implements are affected by weeds, crops, soil conditions, and actuator effectiveness. In order to address these complex and often interacting factors concerning weed control, new and innovative tools must be designed and evaluated. Chapter one …

Farmer Engagement Through Mental Modeling: Opportunities For Climate Change Outreach, Ruth S, Clements

Electronic Theses and Dissertations

Climate change poses a challenge to farming systems worldwide. Effective adaptation and mitigation may be facilitated by outreach that is locally tailored and framed in terms of farmers’ perceptions and values. However, existing research suggests that farmers and those providing outreach may have different climate change perspectives, and there is little understanding of how farmers consider and prioritize climate change in relation to other aspects of their farming system. Furthermore, the diverse agricultural, economic, social, and environmental challenges farmers face require agricultural research and engagement efforts that can identify and adapt to farmers’ dynamic priorities and perceptions. Mental modeling is …

Biogenic Amines As A Product Of The Metabolism Of Proteins In Beer, Hayden Koller

Electronic Theses and Dissertations

For many years the only beer that was commercially available in the United States were simple lagers and ales made primarily of barley (and other cereals), water, hops, and yeast. These beer varieties were simple and quick to produce with high levels of consistency. In the last 30 years the rise in craft and microbreweries have dramatically changed the landscape of brewing and beer. As smaller breweries rose in popularity so did the use of unique ingredients such as vegetables, fruits, herbs, meat, etc. along with higher gravity mashes and long barrel aging times. All these ingredients have a profound …

Does Circularizing Source-Separated Food Waste Present A Risk To Our Food?, Astha Thakali

Electronic Theses and Dissertations

About a third of the food produced annually is wasted. Food waste recycling can be a way to close the loop and attain a more sustainable food system, however, the system must be carefully monitored and managed to avoid the introduction and build-up of contaminants. To study the potential presence of contaminants in food waste, source-separated food waste was collected and screened for five classes of contaminants (physical contaminants, heavy metals, halogenated organic contaminants, pathogens, and antibiotic resistance genes) from two separate regulatory environments (voluntary vs mandated food separation). The regulatory environment did not affect the level of contamination, except …

The Potential For Dickeya Dianthicola To Be Vectored By Two Common Insect Pests Of Potatoes, Jonas K. Insinga

Electronic Theses and Dissertations

Dickeya dianthicola (Samson) causing blackleg and soft rot was first detected in potatoes grown in Maine in 2014. Previous work has suggested that insects, particularly aphids, may be able to vector bacteria in this genus between plants, but no conclusive work has been done to confirm this theory. In order to determine whether insect-mediated transmission is likely to occur in potato fields, two model potato pests common in Maine were used: the Colorado potato beetle (Leptinotarsa decimlineata Say) and the green peach aphids (Myzus persicae Sulzer). Olfactometry and recruitment experiments evaluated if either insect discriminates between infected and …

Landscape Pattern And Wild Bee Communities In Maine, Brianne Du Clos

Electronic Theses and Dissertations

Commercial production of lowbush blueberry (Vaccinium angustifolium Aiton) in Maine relies primarily on managed honeybee hives; however, naturally occurring wild bees are more efficient pollinators of the crop. Wild bees have short foraging distances and must nest near crop fields to provide pollination services. After crop bloom, the surrounding landscape must provide sufficient forage to maintain wild bee populations for the remainder of the growing season. Lowbush blueberries in Maine are produced in a mixed-use landscape with two distinct landscape contexts. Here, we document bee communities and habitat resources (nesting and floral) in power line rights-of-way and eight land …

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 …

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 …

A Comparison Of Seed- And Seedling-Focused Ecologically Based Weed Management Strategies, Bryan Brown

Electronic Theses and Dissertations

Many farmers target weeds at the seedling stage, aiming to control weeds with the minimum amount of labor necessary to avoid crop yield loss. Other farmers with a more long-term, seed-focused approach aim to prevent weeds from setting seed so that emergence will be decreased in subsequent crops. These strategies likely vary in short- and long-term effects on farm ecological and economic health. In 2014–2016, I compared these strategies in a test crop of onion. Unexpectedly, due to high yields, the more labor intensive, seed-focused strategy was the most profitable. Case-study interviews of farmers who have adopted each approach indicated …

Social Ecological Food Systems: Sustainability Lessons From Maine Dairy Networks, Julia B. Mcguire

Electronic Theses and Dissertations

Milk production has played an integral role in the culture, landscape, and economy of Maine’s agriculture. Maine dairy farmers have faced numerous sustainability challenges to economic, environmental, and social aspects of their industry. Like many other complex social ecological systems, the Maine dairy industry faces a gap between scientific knowledge and actionable management or policy. A cultural dichotomy exists between conventional and organic farming. Shifting the focus from this binary, metrics such as social capital may play a key role in solving sustainability issues. Difficulties arise in the governance of complex social ecological systems when the scales of assessment, management, …

Biological, Behavioral And Preventative Management Of The Invasive Insect Pest, Spotted Wing Drosophila (Drosophila Suzukii Matsumura), In Maine Lowbush Blueberry (Vaccinium Angustifolium Aiton), Gabe Alnajjar

Electronic Theses and Dissertations

This research was conducted in order to identify the potential for utilization of various management techniques against the invasive Drosophila suzukii Matsumura, commonly referred to as the spotted wing drosophila (SWD), using Maine lowbush blueberry (Vaccinium angustifolium Aiton) as a model crop system. These included evaluations of three prospective approaches often considered when developing agricultural pest management programs for novel insect pests: 1) biological control through the intended release of natural enemies, in this case entomopathogenic fungi; 2) behavioral management through mass trap deployment in order to capture and kill adult SWD, and; 3) prevention through the deployment of …

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also considered a complex …

The Enhancement Of Wild Bees (Hymenoptera: Apoidea) For Pollination Security, Eric M. Venturini

Electronic Theses and Dissertations

The acreage of pollinator-dependent crops continues to expand across the globe. Simultaneously, honey bee hives – an annually rented commodity that growers rely on – are more expensive every year and in some cases, scarce. In response, pollinator-dependent growers seek alternative pollinators. One approach is installing bee pasture on farms, a strategy that enables systems-based farmers to become in-situ farm-scale habitat managers. This thesis first presents a review of the literature on bee pasture plantings and provides a brief overview of some methods for assessing their impacts on the pollinator community. There are three major gaps in current bee pasture …

Maine Farmers' Perspectives: Barriers And Optimism To Providing Food To Feed Maine People, A Qualitative Study Using Focus Groups, Kelly Ann Ilseman

Electronic Theses and Dissertations

Maine has a history and tradition of agriculture in the state. Some growth in the number of farms in recent years has been due to youth entering agriculture, and in the development of small, diverse farms. There is also public interest in purchasing fresh, local foods. This study was done in conjunction with a University of Maine Cooperative Extension study that assessed Maine farmer’s views of the future of farming in Maine. The farmers (n=189) participated in one of twelve focus groups held across the state and represented a broad sector of Maine agriculture, including vegetable and fruit growers, beef …

Comparisons Of Native And Non-Native Lady Beetles: Habitat Distribution And Interactions With Prey And Competitors, Christy J. L. Finlayson

Electronic Theses and Dissertations

Lady beetles (Coleoptera: Coccinellidae), as a group, are considered beneficial because they prey on plant pests. A number of studies suggest that non-native species introduced for biological control have replaced native species in agriculture. Agricultural and non-agricultural habitats were thus surveyed in Maine to determine if native species were still dominant in some areas. In 2004 and 2005, 3,487 and 2,903 beetles were collected, respectively, with non-native species dominant in all but one habitat (coniferous forest). Native species were found in very low numbers in all habitats surveyed. Comparisons between species were then conducted to determine if differences exist that …

Crop/Livestock Integration Effects On Soil Quality, Crop Production, And Soil Nitrogen Dynamics, Ellen B. Mallory

Electronic Theses and Dissertations

Regional integration of potato and dairy farms has developed in Maine through arrangements where manure, feed, and sometimes land, are exchanged between neighboring farms. The effects of integration on soil quality, crop production, nitrogen (N) cycling, and N loss were investigated in field and laboratory studies of contrasting amended (manure, compost, green manure, and supplemental fertilizer) and nonamended (fertilizer only) soil management systems within 2-year potato (Solanum tuberosum L.) rotations in the Maine Potato Cropping Systems Project (MPEP). Additionally, soil quality of 48 integrated and nonintegrated Maine potato and dairy farm fields was assessed. The MPEP’s amended soil system enhanced …

Assessing The Sustainability Of Agricultural Systems, Laura L. Kramar

Electronic Theses and Dissertations

This work constructs and tests a comparative technique that can be used to determine the ability of agricultural systems to meet multiple objectives of sustainability. Assessments are based on an agricultural system's ability to maintain five system stocks that represent environmental capital, social capital, human capital, physical capital, and financial capital. The capital stocks are measured as stock objectives, which are decomposed as indicators to calculate agricultural system scores. An examination of the complexity of agro-ecosystems and the multiple equilibria produced by balancing multiple objectives is used to explain the alternative criteria used in this comparative technique to evaluate agricultural …

A Spatial Anaylsis Of Passenger Vehicle Attributes, Environmental Impact And Policy, Gregory M. Gould

Electronic Theses and Dissertations

Passenger vehicle use contributes significantly to energy consumption, criteria air pollution and greenhouse gas (GHG) emissions. Recent developments in Geographic Information Systems (GIS) and Vehicle Identification Number (VIN) decoding enable researchers to make use of vehicle registration records to consider the spatial distribution of the vehicle fleet when modeling emissions. In this thesis, these techniques are used to view spatial variation in passenger vehicle attributes and environmental characteristics. The distributions of vehicle type, make and model, size, age, criteria and GHG emission rates, and fuel economy are analyzed. Next, the spatial distribution of private costs and benefits resulting from a …

Dynamics Of Bee And Wasp Populations In Maine Lowbush Blueberry (Vaccinium Angustifolium), Joseph E. Karem

Electronic Theses and Dissertations

Conservation of natural enemies can be an effective form of pest management. If beneficial Hymenoptera, native to the area, can be protected and encouraged to multiply, the benefits of natural insect pest control might be realized. Hymenoptera as "natural enemies" as well as "pollinators" have been studied intensively in many agroecosystems worldwide. However, lowbush blueberry is not an ecosystem where ecology of Hymenoptera has been well studied. This thesis discusses two studies conducted in lowbush blueberry fields in Washington County, Maine in 1997 and 1998. In the first study, I investigated "towers" as a method for deploying insect traps along …