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