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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

VALUE-ADDED STRATEGIES IN THE SPECIALTY CROP INDUSTRY: EXPLORING FARMERS' DRIVERS AND STRATEGIES AT THE FARM LEVEL

Orlando Francisco Rodriguez Izaba (10711716) 06 May 2021 (has links)
Value-added (VA) technologies can help farmers in the specialty crop industry generate new products, increase off-season income sources, expand market access, and improve overall profitability. These technologies can support the development of rural economies through the generation of new businesses and job creation. The USDA defines VA products as those 1) changed physical, 2) produced in a manner that enhances their value, and 3) physically segregated in a manner that results in enhancement of their value. Drawing from this definition, this study investigated VA technologies such as drying, cutting into customer-ready portions, washing and labeling specialty crops. The objectives of this study are threefold. First, we analyze how market access and diversification drive specialty crop farmers to adopt VA technologies. Second, we address the potential endogeneity between the adoption of VA technologies (vertical diversification) and the number of crops (horizontal diversification). Lastly, we investigate how market access drives farmers to utilize food labels for VA products. Data for this study came from a 2019 web-based survey of specialty crop farmers. A total of 766 farmers completed the survey, with a response rate of 21.5%. The questionnaire included questions related to farmer’s demographics (i.e., educational attainment, gender, farming experience), farm characteristics (i.e., crops, markets, and growing technologies), and farmers’ beliefs regarding their farm system. Results suggest that market access is a significant driver of VA technology adoption. Also, the size of the farm, networks, farmer’s perceptions, and employment growth influence adopting VA technologies. The results also show us that farmers adopting VA technologies tend to experience economic growth.
42

<strong>THE  EVALUATION OF MODULAR MANUFACTURING IN CONTROLLED ENVIRONMENT AGRICULTURE FOR  REPURPOSED URBAN SPACES</strong>

Mikael Borge (16648569) 01 August 2023 (has links)
<p>This thesis aims to evaluate a Modular Manufacturing (MM) technical approach to Controlled Environment Agriculture (CEA) for cultivating plant food crops in a repurposed urban space. The specific approach was to fit a modular hydroponic CEA system into an insulated cooler box with environmental control to act as a micro plant factory. The feasibility of the approach was evaluated and a benchmark comparison between repurposed urban space and controlled lab environments was produced.</p><p>Possessing accessibility and affordability to desired quantitatively and nutritious food is a pillar for a healthy lifestyle, yet food insecurity is a growing problem worldwide, in industrial as well as industrializing nations. Food insecurity is defined as “lacking the ability to meet nutritional needs at one or multiple times during the year.” [1] Though Developing countries tend to score poorly on the Food Security Index [2], the issue is common in developed countries as well, where countries like the U.S. Possess a household food insecurity rate of above 10% [1]. Especially, subgroups of the urban population and university students in developed countries are represented at a higher rate concerning food insecurity [3], due to food insecurity’s dependence on socioeconomic factors such as purchasing power and local accessibility.</p><p>Bringing production close to the consumers or to the Point-of-Need (PoN) would be a valuable tool for supplementing traditional food crop production and increasing access to high-quality food for groups exposed to food insecurity. This is especially attractive in densely populated areas and college campuses, where real estate is prime. Bringing production to the PoN does however carry certain challenges, such as severe resource restrictions, which are not present in traditional agricultural production in rural areas where there is vast access to land, water, and plenty of sunlight. Pushing the boundaries of CEA research, technology, and application areas will be crucial for the utilization of nontraditional agricultural land, agricultural resource optimization, and food security improvements in difficult-to-farm environments to facilitate delivery to PoN.</p><p><br></p><p><b>Salient outcomes:</b> The salient outcomes of this research were that a MM platform was proven to be feasible for CEA cultivation of food crops in a repurposed urban space as well as a controlled location. Specimens cultivated in a repurposed urban space were shown to have a lower growth rate compared to a controlled location, but the important comparison is to the currently nonexistent productivity in such spaces.</p><p><b>Intellectual merit:</b> The MM CEA platform was designed, prototyped, and tested using components-of-the-shelf (COTS) as recommended by frugal engineering methodology [4]. This manufacturing platform was engineered for a case study for repurposing unused “garage space” on the college campus at Purdue University. The platform was further used for a set of studies to evaluate the feasibility of the MM platform and the production efficiency of the platform not only in a repurposed urban space but also across harsh environments across winter-spring seasons. Romaine lettuce cultivars were used as a sample plant for winter and spring studies due to their property as a popular consumable, nutritious, and relatively short growth time for better productivity. The following research issues were addressed by this research: (1) design of a modular manufacturing module; (2) testing of the module in the indoor controlled lab environment; (3) advancing design based on findings in no.2; (4) CEA testing of the integration of multiple modules (two and water supply) in the Purdue University garage (living lab) and the indoor lab environment.</p><p><b>Broader Impact:</b> The results from this research could serve as a proof-of-concept to validate the feasibility of functional modules and their integration in scaled-up urban food crop production using repurposed space. This case study especially could open opportunities for college campuses across the US (and the world), to repurpose multi-storied garage spaces for healthy food production at PoN, for example, accessible to students’ dorms and cafeterias. This MM model could further be extended to other forms of urban areas for food security and production in communities in the vicinity of garages and similar spaces in form. Utilizing unrecognized space resources in an otherwise resource-restricted environment could be the supplemental production needed to fight food desertification and insecurity in urban locations. Bringing food production to the PoN would increase the accessibility of high-quality and nutritious fresh produce, improving conditions for localized food insecurity problems.</p>
43

<b>SUPPLEMENTAL IRRIGATION PROGRAM EFFECTS ON VARIOUS LAWN GRASSES IN THE COOL-HUMID ZONE</b>

Antonio Verzotto (18429612) 23 April 2024 (has links)
<p dir="ltr">Water scarcity and acute drought continue to be serious concerns, even in humid climates where precipitation normally exceeds evapotranspiration (ET), highlighting the need for improved landscape water conservation practices. Lawns represent the largest area in most managed landscapes and require regular mowing, feeding and sometimes supplemental summer irrigation to persist. A general historical guideline for lawn irrigation is to supply 25-38 mm per growing wk-1 in the absence of rainfall. This fixed volume is often applied on a programmatic “set and forget” three times per week schedule (e.g. M-W-F). This application guideline often results in excess irrigation as it does not take into account plant need or prevailing environmental conditions. Further, in times of acute summer drought policymakers may restrict irrigation to once or twice weekly to conserve water. The effects of these regulations on turf health and potential water savings are unclear. Thus, two multi-year summer field studies were conducted to identify opportunities for improved lawn water conservation. Study one evaluated the effect of varying weekly irrigation volume and frequency on mature Kentucky bluegrass (Poa pratensis L.:KBG) located under a fixed-roof rainout structure. Turfgrass response was measured as visual turf quality (TQ), digital green color (DGC), volumetric soil water content (VWC) and area under the curve for each response variable. In year one, KBG was subject to six irrigation programs and compared to a high deficit control for 49 days. The programs were: 25 mm total water wk-1 applied either three times (M-W-F) or twice (M and F) weekly, 19 mm total wk-1 twice weekly (M and F), 13 mm total wk-1 once weekly and 60 or 80% accumulated ETo three times weekly. Due to poor performance, the high deficit control and 60% ETo were excluded from further evaluation. In year two, seven programs were evaluated: 33 mm total water wk-1 applied once, twice, or three times weekly, or every-other-day, 25 mm total wk-1 applied twice or three times weekly and 80% ETo twice weekly for 63 days. In both years, generally, 25-33 mm wk-1 applied two or three times wk-1 produced the most consistent TQ, DGC and highest VWC. Study two compared three supplemental irrigation programs to a natural rainfall control for six widely planted cool-season lawn grasses for 70 days. The six lawn grasses were: a KBG sod, seeded drought tolerant and susceptible KBG cultivars, a turf-type tall fescue (Schedonorus arundinaceus (Schreb.) Durmort.: TTTF) blend and two KBG and perennial ryegrass (Lolium perenne L.:PRG) mixtures. In Study two, highly significant differences p < .001 occurred for irrigation program and lawn grasses. While supplemental irrigation aided all grasses, rainfall in year one and two measured 119 mm and 343 mm, respectively, affecting data in each study year. Area under the turfgrass quality curve (AUTQC) was lowest for the rainfall control (339 and 425) and highest for 33 mm wk-1 applied three times (507 and 526) and 80% ETo programs (508 and 535) in year one and two, respectively. Annual responses for DGC and VWC generally followed TQ trends. For grasses subject only to natural rainfall, TTTF, and the KBGs were generally superior to the KBG:PRG mixtures, thus emphasizing the importance of species selection. In summary, these studies compared a traditional “set and forget” irrigation program to a range of alternative programs and different lawn grasses. These data provide evidence for irrigation savings by employing a combination of planting drought tolerant lawn species and adopting a more limited irrigation program. Future field studies should include the evaluation of adaptive, data-driven programs based on forecast environmental conditions and threshold responses like DGC or predetermined VWC set points calibrated for varying soil types and growing environments.</p>
44

Avaliações microclimáticas, fenológicas e agronômicas em café arábica cultivado a pleno sol e consorciado com banana 'Prata Anã'. / Microclimatic, phenological and agronomic evaluations in coffee crop grown under unshaded and shaded by ‘Prata An㒠banana plants conditions.

Pezzopane, José Ricardo Macedo 21 January 2005 (has links)
O presente trabalho foi realizado em cafeeiros (Coffea arabica L.) cv. Icatu Vermelho IAC 4045, cultivados a pleno sol e consorciados com banana ‘Prata An㒠(Musa AAB), em Mococa - SP (Latitude 21º 28’ S, Longitude 47º 01’ W, altitude 665m). Foi realizada a caracterização microclimática, entre outubro de 2001 e setembro de 2002, onde foram medidos a radiação solar global, saldo de radiação, velocidade do vento e temperatura e umidade relativa do ar nos dois sistemas de cultivo. No período do inverno de 2002 e 2003, foi realizado um estudo da influência das bananeiras na variabilidade espacial da temperatura do ar e folha, além do saldo de radiação, em episódios de resfriamento noturno. Realizou-se também uma caracterização aerodinâmica e energética dos cultivos, entre dezembro de 2002 e novembro de 2003, onde foram obtidos os perfis dos bulbos seco e úmido, além da velocidade do vento em sete níveis de medida. Entre julho de 2001 a junho de 2004 foram atribuídas notas de desenvolvimento fenológico dos cultivos, além de se avaliar, o crescimento das plantas em altura e diâmetro da copa. Nas safras de 2002, 2003 e 2004 foram avaliados os parâmetros de produção nos dois sistemas de cultivo, além da variabilidade desses nas parcelas do cultivo consorciado. Houve uma atenuação dos valores de radiação solar global (21%) no cultivo de café consorciado e uma redução de 16% e 48% nos valores do saldo de radiação e velocidade do vento, em relação ao cultivo a pleno sol. Com relação à temperatura e umidade do ar, foram encontradas diferenças apenas na temperatura máxima no ponto central da parcela do cultivo consorciado, que apresentou médias superiores em relação ao cultivo a pleno sol no verão e outono, e em relação ao ponto situado próximo as bananeiras na primavera, verão e outono. Nos episódios de resfriamento do ar no período noturno, apesar do cultivo consorciado apresentar menor perda radiativa, ocorreu apenas um acréscimo de 0,3ºC na temperatura do ar nos episódios amostrados, sendo que para a temperatura das folhas esses valores atingiram até 0,5ºC. Foi verificado ainda que a ação de quebra-vento das bananeiras no cultivo consorciado, promoveu alterações nos perfis de temperatura e umidade do ar, apresentando gradientes reduzidos, em relação ao cultivo a pleno sol, acima do dossel dos cafeeiros. Os valores médios dos componentes do balanço de energia nos sistemas de cultivos de café a pleno sol e consorciado não apresentaram diferenças. Nos sistemas de cultivo avaliados, o crescimento vegetativo em altura e diâmetro apresentou maior atividade vegetativa no período primavera-verão em relação ao período outono-inverno, não tendo sido encontradas diferenças significativas das taxas de crescimento, de desenvolvimento fenológico e dos índices de produção entre os cultivos. No cultivo consorciado, o ponto amostral próximo às bananeiras apresentou diferenças em relação aos demais pontos amostrados no crescimento vegetativo e desenvolvimento fenológico para algumas épocas do ano, além de apresentar menor produção por planta e maior massa de 100 sementes. / A study was carried out in coffee crop (Coffea arabica L.) cv. Icatu Vermelho IAC 4045, unshade and shaded by banana ‘Prata An㒠(Musa AAB), in Mococa, São Paulo State, Brazil (Latitude South 21º 28 ', Longitude West 47º 01 ', altitude 665m). The microclimatic measurements (solar radiation, net radiation, wind speed, air temperature and air moisture) were taken from October, 2001 to September, 2002 under different crops conditions. During the winter of 2002 and 2003, a study of the influence of the banana plants was done on space variability of air and leaf temperature, besides net radiation, for cold nights. The aerodynamic and energy characterization were done from December, 2002 to November,2003, by obtining the profiles of the bulb wet and dry air temperature, also measurements the wind speed in seven different levels. From July, 2001 to June, 2004 phenological data for the coffee crops were taken. The growth of the plants concerning height and diameter was also evaluated. The harvests of 2002, 2003 and 2004 were appraised by the production parameters, and their variability for different positions in shaded coffee crop. The banana trees reduced the incoming solar radiation to the coffee crop by 21%, and by 16% and 48% in the values of the net radiation and wind speed, respectively. Concerning on air temperature and air mosture, differences were found just for the maximum air temperature at the central point of the shaded crop, showing higher averages in relation to the unshaded crop during the summer and autumn, and also in relation to the nearest point to the banana plants during the spring, summer and autumn. During cold nights, spite the shaded coffee crop showing smaller radiation loss, an increment of 0.3ºC in the air temperature was observed and for the leaves the values reached 0.5ºC. It was verified an windbreak action of fanlight of the banana trees in the shaded crop, promoting deviation in air temperature and humidity profiles, showing reduced gradients, in relation to the unshaded crop, above the coffee plants canopy. The mean values of the energy balance components for the different systems of cultivation did not show difference. In the cultivation systems evaluated, the vegetative growth in height and diameter showed higher vegetative activity during the spring-summer period in relation to the autumn-winter period. No significant differences of the growth taxes, of phenological development and of the yield indexes were found. In coffee crop shaded, the nearest point to the banana plants showed differences in relation to the other amostral points in vegetative growth and phenological development for some seasons of the year, besides showing smaller plant yield and higher weight of 100 seeds.
45

Nutzung der räumlichen Variabilität von ausgewählten Standorteigenschaften für die ortsspezifische N-Düngung

Lorenz, Karsten 14 March 2005 (has links)
Für die ortsspezifische Düngung spielt die räumliche Erfassung von ertragsrelevanten Standorteigenschaften (z.B. Textur und Nährstoffnachlieferungsvermögen) eine große Rolle bei der Bemessung der Düngungsempfehlung. Durch die Berücksichtigung der schlaginternen Variabilität ist eine abgestufte standortangepasste Bewirtschaftung möglich. Auf fünf ackerbaulich genutzten Schlägen in verschiedenen Bodenregionen Deutschlands wurden räumliche und zeitliche Untersuchungen zur vertikalen und horizontalen Mineralstickstoffverteilung in Rasterform durchgeführt. Mit Hilfe des N-Modells HERMES wurden Simulationsrechnungen zur N-Dynamik durchgeführt und anhand des volumetrischen Wassergehalts, des Ertrags und des mineralischen Stickstoffgehalts überprüft. Als Referenz dienten die Daten aus der Rasterbeprobung. Die Vergleiche zwischen den simulierten und gemessenen Werten zeigen beim volumetrischen Wassergehalt, beim Ertrag und beim mineralischen Stickstoff auch über mehrere Vegetationsperioden hinweg eine gute Übereinstimmung bei den Mittelwerten, so dass man die Modellergebnisse auch für die N-Düngungsempfehlung herangezogen hat. Datensätze der Reichsbodenschätzung und der digitalen Hofbodenkarte wiesen im Gegensatz zur kleinräu­migen Rasterbeprobung keine ausreichende Genauigkeit bei den räumlichen Verteilungsmustern der ertragsrelevanten Standortgrößen auf und sind demnach nicht als Planungsgrundlage für die ortsspezifische Düngung geeignet. Über Szenariorechnungen lassen sich verschiedene Düngungsvarianten (wie einheitlich und ortsspezifisch gedüngte Variante) für identische Flächen direkt miteinander vergleichen. Die Ergebnisse zeigten beim Einsatz des preagro-N Moduls über drei Vegetationsperioden (2000 bis 2002) ein Einsparungspotential bei der ortsspezifischen Düngung von durchschnittlich 4 %, bei Verwendung der Modellempfehlungen (HERMES) sogar von durchschnittlich 18 % gegenüber der einheitlichen Variante ohne Ertragsdepressionen beführten zu müssen. / For the site-specific fertilization plays the spatial variability of soil parameters (such as texture) an important role for the calculation of fertilizer recommendation. In consideration of spatial variability is a gradual management in the field possible. The distribution of the vertical and horizontal soil mineral nitrogen patterns on five fields were investigated in different regions in Germany. Additionally these data were used for the validation of the nitrogen dynamics of the nitrogen crop growth model HERMES. The comparison between simulate and measurement data showed for the soil moisture, the grain yield and the mineral nitrogen over many vegetation periods good results by the average values. Under this situation is it possible to use simulation model for the nitrogen fertilizer recommendation. Simulations with data sets from the plot sampling (large scale soil map) compared against simulating using German Soil Appraisal or digital farm soil map data showed information losses. The temporal dynamic by soil mineral nitrogen content in the rooting zone and the spatial pattern by the grain yield show a much better agreement with observed values, if large scale data were used for the simulation. The results from the preagro-N model showed at site-specific part over three vegetation periods (2000 to 2002) an economize effect from average 4 % against the uniform fertilisation part. If we had used the fertilizer recommendation from the nitrogen crop growth model HERMES over the same time, the economize effect conducted average 18 % against the uniform fertilisation part without yield depression.
46

Avaliações microclimáticas, fenológicas e agronômicas em café arábica cultivado a pleno sol e consorciado com banana 'Prata Anã'. / Microclimatic, phenological and agronomic evaluations in coffee crop grown under unshaded and shaded by ‘Prata An㒠banana plants conditions.

José Ricardo Macedo Pezzopane 21 January 2005 (has links)
O presente trabalho foi realizado em cafeeiros (Coffea arabica L.) cv. Icatu Vermelho IAC 4045, cultivados a pleno sol e consorciados com banana ‘Prata An㒠(Musa AAB), em Mococa – SP (Latitude 21º 28’ S, Longitude 47º 01’ W, altitude 665m). Foi realizada a caracterização microclimática, entre outubro de 2001 e setembro de 2002, onde foram medidos a radiação solar global, saldo de radiação, velocidade do vento e temperatura e umidade relativa do ar nos dois sistemas de cultivo. No período do inverno de 2002 e 2003, foi realizado um estudo da influência das bananeiras na variabilidade espacial da temperatura do ar e folha, além do saldo de radiação, em episódios de resfriamento noturno. Realizou-se também uma caracterização aerodinâmica e energética dos cultivos, entre dezembro de 2002 e novembro de 2003, onde foram obtidos os perfis dos bulbos seco e úmido, além da velocidade do vento em sete níveis de medida. Entre julho de 2001 a junho de 2004 foram atribuídas notas de desenvolvimento fenológico dos cultivos, além de se avaliar, o crescimento das plantas em altura e diâmetro da copa. Nas safras de 2002, 2003 e 2004 foram avaliados os parâmetros de produção nos dois sistemas de cultivo, além da variabilidade desses nas parcelas do cultivo consorciado. Houve uma atenuação dos valores de radiação solar global (21%) no cultivo de café consorciado e uma redução de 16% e 48% nos valores do saldo de radiação e velocidade do vento, em relação ao cultivo a pleno sol. Com relação à temperatura e umidade do ar, foram encontradas diferenças apenas na temperatura máxima no ponto central da parcela do cultivo consorciado, que apresentou médias superiores em relação ao cultivo a pleno sol no verão e outono, e em relação ao ponto situado próximo as bananeiras na primavera, verão e outono. Nos episódios de resfriamento do ar no período noturno, apesar do cultivo consorciado apresentar menor perda radiativa, ocorreu apenas um acréscimo de 0,3ºC na temperatura do ar nos episódios amostrados, sendo que para a temperatura das folhas esses valores atingiram até 0,5ºC. Foi verificado ainda que a ação de quebra-vento das bananeiras no cultivo consorciado, promoveu alterações nos perfis de temperatura e umidade do ar, apresentando gradientes reduzidos, em relação ao cultivo a pleno sol, acima do dossel dos cafeeiros. Os valores médios dos componentes do balanço de energia nos sistemas de cultivos de café a pleno sol e consorciado não apresentaram diferenças. Nos sistemas de cultivo avaliados, o crescimento vegetativo em altura e diâmetro apresentou maior atividade vegetativa no período primavera-verão em relação ao período outono-inverno, não tendo sido encontradas diferenças significativas das taxas de crescimento, de desenvolvimento fenológico e dos índices de produção entre os cultivos. No cultivo consorciado, o ponto amostral próximo às bananeiras apresentou diferenças em relação aos demais pontos amostrados no crescimento vegetativo e desenvolvimento fenológico para algumas épocas do ano, além de apresentar menor produção por planta e maior massa de 100 sementes. / A study was carried out in coffee crop (Coffea arabica L.) cv. Icatu Vermelho IAC 4045, unshade and shaded by banana ‘Prata An㒠(Musa AAB), in Mococa, São Paulo State, Brazil (Latitude South 21º 28 ', Longitude West 47º 01 ', altitude 665m). The microclimatic measurements (solar radiation, net radiation, wind speed, air temperature and air moisture) were taken from October, 2001 to September, 2002 under different crops conditions. During the winter of 2002 and 2003, a study of the influence of the banana plants was done on space variability of air and leaf temperature, besides net radiation, for cold nights. The aerodynamic and energy characterization were done from December, 2002 to November,2003, by obtining the profiles of the bulb wet and dry air temperature, also measurements the wind speed in seven different levels. From July, 2001 to June, 2004 phenological data for the coffee crops were taken. The growth of the plants concerning height and diameter was also evaluated. The harvests of 2002, 2003 and 2004 were appraised by the production parameters, and their variability for different positions in shaded coffee crop. The banana trees reduced the incoming solar radiation to the coffee crop by 21%, and by 16% and 48% in the values of the net radiation and wind speed, respectively. Concerning on air temperature and air mosture, differences were found just for the maximum air temperature at the central point of the shaded crop, showing higher averages in relation to the unshaded crop during the summer and autumn, and also in relation to the nearest point to the banana plants during the spring, summer and autumn. During cold nights, spite the shaded coffee crop showing smaller radiation loss, an increment of 0.3ºC in the air temperature was observed and for the leaves the values reached 0.5ºC. It was verified an windbreak action of fanlight of the banana trees in the shaded crop, promoting deviation in air temperature and humidity profiles, showing reduced gradients, in relation to the unshaded crop, above the coffee plants canopy. The mean values of the energy balance components for the different systems of cultivation did not show difference. In the cultivation systems evaluated, the vegetative growth in height and diameter showed higher vegetative activity during the spring-summer period in relation to the autumn-winter period. No significant differences of the growth taxes, of phenological development and of the yield indexes were found. In coffee crop shaded, the nearest point to the banana plants showed differences in relation to the other amostral points in vegetative growth and phenological development for some seasons of the year, besides showing smaller plant yield and higher weight of 100 seeds.
47

AN INTEGRATED CULTURAL MANAGEMENT APPROACH FOR BROWN PATCH DISEASE SUPPRESSION IN TALL FESCUE LAWNS

Jada S Powlen (6620417) 24 April 2023 (has links)
<p> Brown patch (caused by various <em>Rhizoctonia </em>and <em>Rhizoctonia-</em>like species) is one of the major summer diseases of tall fescue [<em>Schedonorus arundinaceus</em> (Schreb.) Dumort., nom. cons.]. Fungicides are available to suppress brown patch; however, there is increasing interest to reduce lawn pesticide inputs. Excessive summer nitrogen (N) applications and extended periods of leaf wetness have been suggested to enhance brown patch. Five projects were conducted from 2020 to 2022 to evaluate individual and various combinations of cultural management practices to improve brown patch management strategies through reducing chemical inputs and promoting environmentally sound integrated pest management (IPM) practices. Brown patch host resistance of 15 tall fescue cultivars was evaluated in a controlled environment study and various morphological characteristics were correlated to brown patch severity. A 45% reduction in brown patch was observed with a resistant cultivar, and cultivars with faster growth rates, wider sheath widths and shorter sheath length correlated with reduced brown patch resistance. A field study evaluated five cultivars fertilized with urea-N from April to July, totaling 73.5 or 245.0 kg N ha<sup>-1</sup>. A resistant cultivar had the greatest influence on reducing disease, and N-rate generally did not influence disease severity. Differences in seasonal brown patch was compared in a three-year field study for various natural organic fertilizers. Feather-bone meal and soybean meal-based products decreased disease compared to non-fertilized turf. Chemical suppression of leaf-wetness was studied using different surfactant chemistries applied on a 14 to 21-d application frequency and some chemistries reduced disease. When evaluating the various interactions of cultivar, N rate, and surfactant compared to a granular fungicide, the greatest impact was achieved when planting a resistant cultivar, reducing disease severity by 68%. Additionally, the combination of a resistant cultivar and application of a surfactant had the same seasonal brown patch compared to a susceptible cultivar with fungicide applications during year two of evaluation. In summary, these studies demonstrate significant reductions in brown patch can be achieved when utilizing the aforesaid best management practices which can substantially reduce the need for frequent lawn fungicides.  </p>
48

EXAMINING EFFECTS OF LIGHT QUALITY ON CANNABIS AND THE CANNABIS APHID (PHORODON CANNABIS)

Eze Pojmann Ezeonyilo (14237201) 12 December 2022 (has links)
<p>  </p> <p>Environmental conditions, like light quality and herbivory, can induce changes in plant physiology. Light quality can be manipulated using LEDs (light emitting diodes) to improve crop quality and yield in horticultural production. The manipulation of light quality has also been utilized in the management of agricultural insect pests. Previous research has provided evidence that changes in light quality can have effects on the growth and chemistry of cannabis crops (<em>Cannabis spp.</em>). Varieties of cannabis are grown for the production of the valued cannabinoids CBD and THC. Pest of cannabis include herbivorous arthropods that reduce hemp yield and quality. Arthropod herbivory can induce chemical and physical changes in plants. This thesis further investigates the role of light quality on both cannabis biology and the crop-pest interaction between cannabis and the cannabis aphid (<em>Phorodon cannabis</em>). In the experiments described herein, the effects of light quality and <em>P. cannabis </em>herbivory on cannabis were assessed by measuring impact on biomass accumulation, yield, and the production of CBD and THC. The effects of light quality on the life history traits of <em>P. cannabis </em>were also measured. Cannabis grown under red-blue light quality saw a reduction in vegetative growth but no reduction in yield. Light treatments had no measured effect on the concentrations of CBD and THC in the cannabis buds. Aphid herbivory decreased bud yield but increased vegetative growth. Aphid herbivory reduced the concentration of both CBD and THC in cannabis bud tissue. Under blue-rich light quality, <em>P. cannabis </em>experienced higher reproductive rates when compared to red-blue and full-spectrum lighting. </p>
49

ORGAN-SPECIFIC EPIGENOMIC AND TRANSCRIPTOMIC CHANGES IN RESPONSE TO NITRATE IN TOMATO

Russell S Julian (8810357) 21 June 2022 (has links)
Nitrogen (N), an essential plant macronutrient, is among the most limiting factors of crop yield. To sustain modern agriculture, N is often amended in soil in the form of chemical N fertilizer, a major anthropogenic contributor to nutrient pollution that affects climate, biodiversity and human health. To achieve agricultural sustainability, a comprehensive understanding of the regulation of N response in plants is required, in order to engineer crops with higher N use efficiency. Recently, epigenetic mechanisms, such as histone modifications, have gained increasing importance as a new layer of regulation of biological processes. However, our understanding of how epigenetic processes regulate N uptake and assimilation is still in its infancy. To fill this knowledge gap, we first performed a meta-analysis that combined functional genomics and network inference approaches to identify a set of N-responsive epigenetic regulators and predict their effects in regulating epigenome and transcriptome during plant N response. Our analysis suggested that histone modifications could serve as a regulatory mechanism underlying the global transcriptomic reprogramming during plant N response. To test this hypothesis, I applied chromatin immunoprecipitation-sequencing (ChIP-Seq) to monitor the genome-wide changes of four histone marks (H3K27ac, H3K4me3, H3K36me3 and H3K27me3) in response to N supply in tomato plants, followed by RNA-Seq to profile the transcriptomic changes. To investigate the organ specificity of histone modifications, I assayed shoots and roots separately. My results suggest that up to two-thirds of differentially expressed genes (DEGs) are modified in at least one of the four histone marks, supporting an integral role of histone modification in regulating N response. I observed a synergistic modification of active histone marks (H3K27ac, H3K4me3 and H3K36me3) at gene loci functionally relevant to N uptake and assimilation. Surprisingly, I uncovered a non-canonical role of H3K27me3, which is conventionally associated with repressed genes, in modulating active gene expression. Interestingly, such regulatory role of H3K27me3 is specifically associated with highly expressed genes or low expressed genes, depending on the organ context. Overall, I revealed the multi-faceted role of histone marks in mediating the plant N response, which will guide breeding and engineering of better crops with higher N use efficiency
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Par?metros fisiol?gicos, qu?micos e biol?gicos da cana-de-a??car (Saccharum spp.) em solo cambissolo eutr?fico sob condi??es de colheita com e sem queimada / Sugarcane (Saccharum spp.) physiological, chemical and biological parameters on inceptsol soil under crop conditions with and without burning

BERTO, Pedro Nilson Alves 12 December 2000 (has links)
Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2016-08-17T18:27:17Z No. of bitstreams: 1 2000 - Pedro Nilson Alves Berto.pdf: 654186 bytes, checksum: ef66a21a2e6b0ca326c348f84fb13d3e (MD5) / Made available in DSpace on 2016-08-17T18:27:17Z (GMT). No. of bitstreams: 1 2000 - Pedro Nilson Alves Berto.pdf: 654186 bytes, checksum: ef66a21a2e6b0ca326c348f84fb13d3e (MD5) Previous issue date: 2000-12-12 / CHAPTER I: In a Inceptisol soil, at Santa Cruz Sugar Mill, Campos dos Goytacazes/RJ, an experiment was conducted with the purpose to evaluate, during the cycle of second ratoon answers to the application of sugarcane agroindustry wastes, in consitions of harverst management with and without previous burning, using the growth quantitative analysis and utilizing the RB72454 sugarcane variety. The experimental field was planted in April 1992. The plant cane cut ocurred in July 1993. The first ratoon was harvested in August 1994, when the test was reinstalled to evaluation in the second ratoon, which harvest was in September 1995. The tested treatment were: 1 = CC = raw cane; 2 ? CC + TF = raw cane + 30 t.ha-1 of filter cake; 3 ? CC + TF + B = raw cane + 20 tons of filter cake ha-1 + 10 t.ha-1 of bagasse; 4 ? CQ = burned cane; 5 ? CQ + TF = burned cane + 30 t.ha-1 of filter cake; 6 ? CQ + TF + B = burned cane + 20 t.ha-1 of filter cake + 10 t.ha-1 of bagasse. The physiological rates discussed and interpreted were: a) Number of stalks by linear meter; b) Stalk height (m); c) Total biomass (g.m-2 soil); d) Leaf area index (m2 leaf. m-2 soil); e) Growth tax of the cultural (g.m-2 leaf. day-1); f) Liquid assimilation tax (g.m-2 leaf.day-1); g) Leaf nitrogen concentration; h) Stalk nitrogen concentration. The results allowed the following conclusions: 1) The application of the sugar agroindustry wastes (filter cake and bagasse) in areas harvest with or without burning, didn?t increased the stalks number and canes height. 2) The fact of not have significant differences to the stalks number rates by linear meters and canes height, reflected directly in a not statistical difference among the evaluated treatments, beeing relative a industrial stalks final productivity in t.ha. 3) The value of total biomass, obtained in the various treatments, was very low, mainly in function of hydric deficit ocurred in the period of the development of the experiment. 4) O I.A.F. (leaf area index), showed little significant changes in the first samples (second, fourth and sixth months), with higher values to burning treatments, in function of a higher stalks number by meter found in this parcels. 5) The straw index calculated (20, 6 t.ha-1) affected the ratoon budding, lowing the stalks population. 6) The leaf area index stayed lower than that considered ideal to the development of a productive sugarcane plantation, correlating with the law productivity obtained, beeing a good physiological parameter to the estimation of a sugarcane?s production. 7) The growth tax of the culture showed the highest values between 120 e 240 days after cut, similar to all treatments during the vegetative development cycle and coincided to the highest foliar area index. 8) The liquid assimilation tax was affected by the hydric stress in the period of the maximum growth of the culture. 9) The nitrogen leafs concentration, as the nitrogen stalks concentration didn?t show differences among the treatments. The fact that the soil studied was a Inceptisol soil, with great natural fertility and that ocurred a great hydric stress during the culture cycle, may have equalized the answers. -------------------------------------------------------------------- CHAPTER II: In a Inceptisol soil of Santa Cruz sugar mill; located at Campos dos Goytacazes,RJ, an experiment was conducted to evaluate the influence, in the chemical and biological properties of the soil, during the sugar cane second ratoon, of the sugar industry wastes (filter cake and bagasse) applied into experimental parcels harvested with and without previous burning of the cane. The experimental field was planted in April 1992. The harvest of the cane ocurred in July 1993. The first 1994, ratoon was harvested in August when the experiment was reinstalled for evaluation in the second ratoon, which harvest was done in September 1995. The tested treatments were: 1= CC= raw cane; 2- CC+TF= raw cane + 30 t.ha -1 of filter cake; 3-CC+TF+B= raw cane + 20 tons of filter cake ha-1 + 10 t. ha-1 of bagasse; 4-CQ= burned cane; 5- CQ +TF= burned cane + 30 t ha-1 of filter cake; 6-CQ + TF + B= burned cane + 20 t.ha-1 of filter cake + 10 T.ha-1 of bagasse. The parameters discussed and interpreted were: a) manufacturable stalks productivity in t.ha-1; b) Sugar production in t Pol ha -1; c) microbial soil biomass-carbon in mgCg -1 of soil; d) agroindustrial wastes effect among treatments on the productivity of second and the third curts of the in t.sugarcane ha-1; e) treatments effects on soil chemical properties; f)straw index determination. The results allowed the following conclusions: 1- The application of the sugar agroindustry wastes (filter cake and bagasse), in the sugar cane fields harvested with or without burning, didn`t result in increasing of productivity, in t.ha-1 or in t.ha-1. 2- Raw cane treatments, that received industrial wastes, showed expressive higher values of BMS-C, in comparison with burned cane treatments, mainly in raw cane treatment with filter cake. 3- The Inceptisol soil, may have facilitaded the similarity of the production results (t cane ha-1), due to the its high natural fertility. 4- Straw index, equivalent to 20,6 t. straw ha, may have affected the ratoon budding of the raw cane treatments. 5- generally speaking, the soil chemical properties studied haven`t been modified when the treatments are compared. / CAP?TULO I: Em solo Cambissolo eutr?fico, da usina Santa Cruz, RJ, foi conduzido experimento objetivando avaliar, durante ciclo de segunda soca (terceiro corte da cultura da cana-de-a??car), respostas ? aplica??o de res?duos da agroind?stria a?ucareira, em condi??es de manejo de colheita com e sem pr?via queima, utilizando-se da an?lise quantitativa de crescimento e empregando-se a variedade RB72454. O campo experimental foi plantado no m?s de abril de 1992. O corte da cana-planta ocorreu em julho de 1993. A primeira soca foi colhida em agosto de 1994, ocasi?o em que se reinstalou o ensaio para avalia??o na Segunda soca ou terceiro corte, cuja colheita aconteceu em setembro de 1995. Os tratamentos efetuados foram: 1 ? CC = cana-crua; 2 ? CC + TF = cana crua + 30 toneladas. ha-1 de torta de filtro; 3 ? CC + TF + B = cana-crua + 20 toneladas de torta de filtro . ha-1 + 10 toneladas . ha-1 de baga?o; 4 ? CQ = cana queimada; 5 ? CQ + TF = cana queimada + 30 toneladas . ha-1 de torta de filtro; 6 ? CQ + TF + B = cana queimada + 20 toneladas . ha-1 de torta de filtro + 10 toneladas . ha-1 de baga?o. Os par?metros fisiol?gicos discutidos e interpretados foram: a) n?mero de colmos por metro linear; b) altura do colmo (m); c) fitomassa total (g.m-2 solo); d) ?ndice de ?rea foliar (m2 folha . m-2 solo); c) taxa de crescimento da cultura (g. m- 2 solo.dia-1); f) taxa de assimila??o l?quida (g.m-2 folha.dia-1); g) concentra??o de nitrog?nio nas folhas; h) concentra??o de nitrog?nio no colmo. Os resultados obtidos permitiram as seguintes conclus?es: 1. A aplica??o dos res?duos da agroind?stria a?ucareira (torta de filtro e baga?o), nas ?reas colhidas com e sem queima, n?o resultou em aumento no n?mero de colmos por metro linear e nem na altura das canas. 2. O fato de n?o haver diferen?as significativas para os par?metros n?mero de colmos por metro linear e de altura das canas, refletiu-se diretamente na n?o diferen?a estat?stica entre os tratamentos avaliados, no que se refere ? produtividade final dos colmos industrializ?veis em t.ha-1. 3. O valor da fitomassa total, obtida nos diversos tratamentos, apresentou-se muito baixo, em fun??o principalmente do d?ficit h?drico ocorrido no per?odo de condu??o do experimento. 4. O I.A.F. (?ndice de ?rea foliar), apresentou varia??es significativas nas primeiras amostragens (segundo, quarto e sexto meses), com valores maiores para os tratamentos com queima, em fun??o de maior n?mero de colmos por metro encontrado nestas parcelas. 5. O ?ndice de palhi?o calculado (20,6 t.ha-1) afetou a brota??o de soqueiras dos tratamentos com cana crua, prejudicando a popula??o de colmos. 6. O ?ndice de ?rea foliar ficou abaixo do considerado ideal para a forma??o de lavoura produtiva, correlacionando-se com a baixa produtividade obtida, mostrando-se como um bom par?metro fisiol?gico para estimativa da produ??o canavieira. 7. A taxa de crescimento da cultura apresentou valores m?ximo entre 120 e 240 dias ap?s o corte, foi semelhante para todos tratamentos ao longo do ciclo de desenvolvimento vegetativo e coincidiu com os per?odos de ?ndice de ?rea foliar m?ximos. 8. A taxa de assimila??o l?quida foi afetada pelo estresse h?drico no per?odo de m?ximo crescimento da cultura. 9. A concentra??o de nitrog?nio nas folhas, assim como a concentra??o de nitrog?nio nos colmos, n?o apresentou diferen?as entre tratamentos. O fato de o solo estudado ser um Cambissolo eutr?fico, com alta fertilidade natural e de ter ocorrido forte stress h?drico durante o ciclo da cultura, pode ter nivelado as respostas. -------------------------------------------------------------------- CAP?TULO II: Num Cambissolo eutr?fico da usina Santa Cruz, localizada no munic?pio de Campos dos Goytacazes, RJ, foi conduzido experimento objetivando avaliar, durante ciclo de segunda soca (terceiro corte) da cultura da cana-de-a??car, o efeito de res?duos da fabrica??o do a??car, (torta de filtro e baga?o), aplicados em parcelas experimentais posteriormente colhidas com cana crua e com cana sem queima, nas suas propriedades qu?micas e biol?gicas. O campo experimental foi plantado no m?s de abril de 1992. O corte da cana-planta ocorreu em julho de 1993. A primeira soca foi colhida em agosto de 1994, ocasi?o em que se reinstalou o ensaio para avalia??o na segunda soca ou terceiro corte, cuja colheita aconteceu em setembro de 1995. Os tratamentos efetuados foram: 1 ? CC = cana crua; 2 ? CC + TF = cana crua + 30 toneladas.ha-1 de torta de filtro; 3 ? CC + TF + B = cana crua + 20 toneladas de torta de filtro.ha-1 + 10 toneladas.ha-1 de baga?o; 4 ? CQ = cana queimada; 5 ? CQ + TF = cana queimada + 30 toneladas .ha-1 de torta de filtro; 6 ? CQ + TF + B = cana queimada + 20 toneladas.ha-1 de torta de filtro + 10 toneladas.ha-1 de baga?o. Os par?metros discutidos e analisados foram: a) produtividade de colmos industrializ?veis em t.ha-1; b) produ??o de a??car em t POL.ha-1; c) biomassa microbiana do solo-carbono em mgC.g-1 de solo; d) efeito dos res?duos agroindustriais entre tratamentos, nas produtividades dos segundo e terceiro cortes, em t cana.ha-1; e) efeito dos tratamentos sobre as propriedades qu?micas do solo; f) determina??o do ?ndice do ?palhi?o?. Os resultados obtidos permitiram as seguintes conclus?es: 1 ? A aplica??o dos res?duos da agroind?stria a?ucareira (torta de filtro e baga?o), nos canaviais colhidos com e sem queima, n?o resultou em aumentos de produtividade, quer seja em t cana.ha-1 ou em t pol.ha-1. 2 ? Os tratamentos com cana crua que receberam res?duos industriais, apresentaram valores significativamente maiores de BMS-C, em compara??o ao tratamento cana queimada. Houve uma maior propor??o de carbono imobilizado na biomassa microbiana do solo, principalmente no tratamento cana crua com torta de filtro adicionada. 3 ? O tipo de solo estudado, Cambissolo Eutr?fico, pode ter facilitado a semelhan?a dos resultados de produ??o (t cana.ha-1), em fun??o de sua alta fertilidade natural. 4 ? O ?ndice de Palhi?o, equivalente a 20,6 t.ha-1 de palha, pode ter afetado a brota??o de soqueiras dos tratamentos com cana crua. 5 ? De modo geral, as propriedades qu?micas do solo estudadas n?o foram alteradas quando se compararam os tratamentos.

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