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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.
1

Comparing hand watering, automated, and subsurface irrigation treatments for cost, labor, and water use in community gardens.

De Leon Gonzalez, Eloísa Maria 06 August 2021 (has links)
Community gardens are places where people gather to share the experience of gardening. However, users often struggle to find time in their busy schedules to care for their plots and crops. This research explores the impact of different watering systems on gardening based on plant quality, cost, labor, and time for. The study analyzed the inputs and outputs of hand watering, automated, and subsurface irrigation treatments in hopes of identifying how to design community gardens for the most efficient application of water, ultimately striving to increase crop production, crop quality, and community interest. Results indicate that subsurface irrigation systems are more likely to save time, reduce water use, and produce a higher quality crop when application and setting is adequate.
2

Aplicação de água residuária doméstica pelos métodos de aspersão e gotejamento subsuperficial na grama Esmeralda / Application of domestic wastewater by subsuperficial spraying and spray methods in the Emerald grass

Mendonça, Rafael Barcelos [UNESP] 25 August 2017 (has links)
Submitted by RAFAEL BARCELOS MENDONÇA null (rafael.irrigacao@gmail.com) on 2017-10-23T19:22:08Z No. of bitstreams: 1 Dissertacao_Rafael Barcelos_FINAL_CORRIGIDO_Ficha e Certidão.pdf: 4852226 bytes, checksum: acef517d0d7b0c74de18292d5f9ed725 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-10-23T19:31:51Z (GMT) No. of bitstreams: 1 mendonca_rb_me_bot.pdf: 4852226 bytes, checksum: acef517d0d7b0c74de18292d5f9ed725 (MD5) / Made available in DSpace on 2017-10-23T19:31:51Z (GMT). No. of bitstreams: 1 mendonca_rb_me_bot.pdf: 4852226 bytes, checksum: acef517d0d7b0c74de18292d5f9ed725 (MD5) Previous issue date: 2017-08-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A Zoysia japonica Steud, conhecida com grama esmeralda, é uma das principais gramas comercializadas no Brasil. Essa espécie apresenta boa capacidade de resistência à pisoteio sendo a espécie de grama da maioria dos gramados residenciais brasileiros. A utilização da irrigação para manutenção de gramados é um dos muitos gargalos no uso de água nas cidades. Uma opção para o suprimento de água e nutrientes da grama esmeralda é a utilização da água residuária doméstica, que é rica em nutrientes. Objetivou-se com esse trabalho estudar a lâmina mínima de água que preserve a qualidade visual do gramado, aplicada através dos métodos de irrigação por aspersão e gotejamento subsuperficial. O trabalho foi realizado no Departamento de Solos e Recursos Ambientais da Faculdade de Ciências Agronômicas de Botucatu – Unesp (Universidade Estadual Paulista “Júlio de Mesquita Filho”). O gramado foi estudado nos períodos do inverno e da primavera, com início em junho de 2016 e finalização em dezembro de 2016. O delineamento experimental adotado foi em blocos casualizados composto por 8 tratamentos e o controle, dispostos em parcelas subdivididas e quatro repetições. Os tratamentos consistiram em dois métodos de irrigação (aspersão e gotejamento subsuperficial – parcelas) e quatro lâminas de água residuária doméstica (50%, 100%, 150% e 200% da evapotranspiração média diária – subparcela) e o controle com água tratada fornecida pela Companhia de Saneamento – Sabesp de Botucatu/SP, repondo 100% da evapotranspiração média diária. Foram estudadas as seguintes características: concentração dos nutrientes no solo, massa seca das aparas, quantidade de nutrientes nas aparas, intensidade de cor verde, altura do gramado, tração do gramado, sistema radicular, e taxa de cobertura verde do gramado. Os resultados indicaram que através da aplicação de água residuária doméstica houve um aumento da massa de grama produzida, coloração verde, massa seca, altura e taxa de cobertura do gramado, para ambos os sistemas de irrigação, em vantagem o sistema de gotejamento por não conter contaminação excessiva no tecido vegetal por Escherichia coli. / The Zoysia japônica Steud, known as the emerald grass, is one of the most traded grass in Brazil. This specie show good capacity of trampling resistance being the grass specie from the major Brazilian residential lawns. The irrigation use for lawn maintenance is one of the many neck for water use in the cities. One option for water and nutrients supply of emerald grass is the use of domestic waste water, which is rich in nitrogen. This work aimed to study the minimum water line that preserves the lawn visual quality, applied through sprinkling and subsuperficial dribbling irrigation methods. The work was done at the Soil and Environmental resources department of the Agronomic Science College – UNESP (Sao Paulo state university “Júlio de Mesquita Filho”). The lawn was studied in winter and spring periods, initiating in june/2016 and ending in December/2016. The trail delineation adopted was randomized blocks composed by eight treatments and a control, disposed in subdivided parcels and four repetitions. The treatments consisted in two irrigation methods (sprinkling and subsuperficial dribbling – parcels) and four domestic waste water lines (50%, 100%, 150% and 200% of the daily mean evapotranspiration – subparcel) and the control with treated water supplied by the sanitation company – SABESP of Botucatu – SP, replacing 100% of the daily mean evapotranspiração. It was studied the following characteristics: soil nutrient concentration, shavings dry matter mass, shaving nutrient quantity, green color intensity, lawn height, lawn traction, radicular system, lawn green coverage rate. The results indicate that trough the domestic waste water application, there was an increase in produced lawn mass, green coloration, dry mass, lawn coverage height and rate for both the irrigation systems, leveraging the dribbling system. In dribbling irrigation method there was no excessive contamination in vegetal tissue by Escherichia coli.
3

Certain Agave Species Exhibit the Capability to be Moderately Productive Under Conditions of High Salt and Drought Stress

Bergsten, Steven J. 13 December 2013 (has links) (PDF)
Water availability and arable lands are increasingly limiting resources in many parts of the U.S., particularly in semi-arid and arid regions. As a means of addressing food and fuel demands associated with burgeoning population growth, highly productive and water-use efficient crops need to be identified. One potential crop, Agave, merits consideration and evaluation due to its putative capability to provide sustenance and energy despite growing in water-limited regions and on marginal soils. However, little is known regarding the productivity these succulent plants will have under growing conditions of the Southwest, where high concentrated saline soils are abundant, and water is often limited. The objectives of these studies were to determine the effects of high levels of salinity and different volumetric water content levels (VWC) on plant growth, biomass accumulation, and nutrient uptake. I used a hydroponic study to compare the effects of four salinity treatments (0.5, 3, 6, and 9 dS m-1) on productivity of four Agave species (Agave parryi, Agave utahensis ssp. kaibabensis, Agave utahensis ssp. utahensis, and Agave weberi). In a second study, an automated irrigation system was established to examine four pre-determined VWC threshold set-points and simulated a gradient of well-watered to drought conditions, to evaluate how A. weberi would respond to varying levels of water availability. Salinity concentrations did not significantly affect root and plant dry weight accumulation in A. weberi, but all other agave plants experienced less biomass accumulation under high saline conditions (>6 dS m-1). Seedlings of A. utahensis were two times more likely to die in the two highest saline treatments (6 and 9 dS m-1) than the two lower treatments (0.5 dS m-1 and 3 dS m-1). Calcium, Mg, S, Mn levels decreased in both A. parryi and A. weberi at higher salinity levels. Agave weberi was able to tolerate salinity, but it also experienced lower biomass production ≤3 dS m-1. In the water-stress study, Agave weberi plants experienced a decrease of 2.11 g as compared to plants in the highest treatment. Plants in the intermediate VWC treatments had similar dry mass values as those in the highest treatment, which suggests that this species could have moderately high yields under limited water conditions, and consequently should be evaluated as a potential bioenergy crop for semi-arid regions, such as the U.S. Southwest. Agave shows considerable potential to be grown in arid and semi-arid regions that are moderately high in salinity and have limited water availability. Indeed, the cultivation of Agave as a crop appears to be a viable option for many areas of the Southwest. While some of the Agave species evaluated were quite productive under moderate salt and water stress, it is uncertain if growth will be significantly reduced if under these stress conditions for periods longer than 3 months.
4

Exploring the Possibility of Photosynthetic Plasticity in <em>Agave sensu lato</em>

Huber, John Anthony 01 June 2016 (has links)
Crassulacean acid metabolism (CAM) provides desert plants with distinct advantages over the C3 and C4 photosynthetic pathways in harsh climates where water is scarce. CAM is, however more metabolically costly than C3 or C4 photosynthesis, and some plants, such as Mesembryanthemum crystallinum, facultatively utilize CAM when water is abundant, and water conservation unnecessary. In such situations, these plants behave akin to a C3 plant when photosynthesizing. CAM is divided into four phases, with each phase displaying unique metabolic processes. Certain changes, including changes in the timing of CO2 fixation, stable carbon isotope ratios, and tissue malic acid content accumulation patterns can indicate that a plant has shifted from CAM to C3 photosynthesis. Such shifts have been observed to be regulated primarily by water availability and ontogenic development. While facultative CAM is well documented in species like Mesembryanthemum crystallinum, and it has not been studied extensively in Agave with the exception of Agave deserti, and Agave angustifolia. A better understanding of this phenomenon would apply to the agricultural growth of this genus. This study aimed to trigger C3 to CAM shifts in Agave sensu lato species, in order to expand upon the findings of previous studies, and better understand the prevalence of facultative CAM expression in the genus. Gas exchange and stable carbon isotope measurements were taken from 2-month-old, 10-month-old, and mature agaves grown in controlled ocnditions. Tissue acid content measurements were taken from mature plants. Despite the Agave sensu lato species in this study being subjected to moisture applications ranging from dry to saturated, we were unable to observe any distinct shifts from CAM to C3 photosynthesis in any of the species tested for both seedlings and mature plants. Diel net CO2 fixation rates also increased with age, and water applications for seedlings, and decreased with heavy irrigation in mature plants. Stable carbon isotope ratios revealed that some carbon in the plant tissues was fixed by rubisco, and that some species (Polianthes tuberosa, Prochnyanthes mexicana) had carbon isotope ratios of a C3 plant, but these ratios did not change with different irrigation treatments. Malic acid accumulation remained typical of CAM plants for the species tested as well, with one exception in Polianthes tuberosa. As such, we conclude that the Agave sensu stricto species tested in this study are obligate CAM plants, and that they perform poorly mature individuals are over-watered. Additionally, the Agave sensu lato species P. mexicana, and P. tuberosa appear to be C3 plants given the results of this study.
5

Resurseffektiv bevattning i ett föränderligt klimat / Resource-efficient irrigation in a changing climate

Rahman, Salman January 2024 (has links)
Södra Gotland (Storsudret) är ett av de mest utsatta områdena i Sverige när det kommer till torka under somrarna. Trots stora mängder nederbörd har jordbrukare problem med bevattning då öns geologi påverkar lagringen av vatten i form av grundvatten negativt. Vilket beror på att berggrunden består främst av kalk, märgel och märgelsten. Dålig tillgång till vatten kombinerat med långa och varma somrar har medfört att skörden minskat markant under de senaste åren. Bevattningstekniker som används i dagsläget är inte bra på att utnyttja vatten på ett hållbart och effektivt sätt. Dessutom har kostnaderna ökat för många jordbrukare på Gotland med avseende på de ökande elpriserna. Bevattning kräver el och vissa bönder har exempelvis inte tillgång till el vid sina åkrar och måste därmed dra el vilket ökar kostnaderna markant. Behovet av mer resurseffektiva och hållbara bevattningstekniker är stort och något som behöver undersökas mer djupgående.  Syftet med denna studie var att undersöka ifall ett automatiserat bevattningssystem som drivs av solenergi faktiskt är möjligt att implementera. Detta utifrån olika kriterier såsom kostnad, energianvändning, skördemängd, klimatpåverkan och vattenanvändning. Därefter jämföra mot ett mer konventionellt system som används i dagsläget och därmed undersöka vilka skillnader det finns. Det var två system som valdes i studien. System 1 var ett potentiellt automatiserad rampbevattningssystem och system 2 ett konventionellt rampbevattningssystem. Båda systemen sattes in i verklighetsbaserade scenario (en åker i södra Gotland) för att få en mer realistisk överblick. Därefter användes en multikriterieanalys för att jämföra båda systemen mot varandra utifrån valda kriterier. Sist av allt användes en SWOT-analys för att sammanknyta all resultat som togs fram i studien.  Resultatet visade att det är i teorin möjligt att bygga ett helt automatiserat bevattningssystem som drivs av solenergi och att det finns både positiva och negativa delar med systemet jämfört mot en konventionell rambevattning. Det potentiella systemet har exempelvis både en högre kostnad som 1,1 gånger högre, samt en högre energianvändning per hektar, cirka 5 gånger högre jämfört med ett konventionellt system. Dock presterade det potentiella systemet bättre jämfört mot ett konventionellt system med avseende på klimatpåverkan som var 10 gånger lägre jämfört med ett konventionellt system. SWOT sammanställningen visade också att intresset för automatiserade bevattningssystem är låg bland jordbrukare delvis på grund av att systemen inte är anpassade till svenska förhållanden, samt den höga investeringskostnaden. Därav krävs det att fler aktörer blir involveras och kunskapen sprids för att öka etableringen av automatiserade bevattningssystem på södra Gotland (Storsudret) samt resten av Sverige. / The southern part of Gotland (Storsudret) is one of the most exposed areas in Sweden when it comes to drought during the summers. Despite large amounts of rainfall, farmers have problems with irrigation as the island’s geology negatively affects the storage of water in the form of groundwater. Poor access to water combined with long and hot summers has meant that the harvest has decreased significantly in recent years. Irrigation techniques used today are not good at using water sustainably and efficiently. In addition, costs have increased for many farmers in Gotland concerning the increasing electricity prices. Irrigation requires electricity and some farmers, for example, do not have access to electricity in their fields and thus have to get electricity, which increases costs significantly. The need for more resource-efficient and sustainable irrigation techniques is great and something that needs to be investigated in more depth.  The purpose of this study was to investigate whether an automated irrigation system powered by solar energy is realistically possible to implement. This was based on various criteria such as cost, energy requirements, yield, etc., and then compare against a more conventional system that is currently used and thus examines what differences there are. Two systems were chosen in the study. System one was a potentially automated irrigation system and system two was a conventional ramp irrigation system. Both systems were put into a reality-based scenarios (a field in southern Gotland) to get a more realistic overview. Multi-criteria analysis was then used to compare both systems against each other based on selected criterias. Afterward, a SWOT analysis was also carried out to summarize all the results that were produced in the study.  The result showed that it is theoretically possible to build a fully automated irrigation system powered by solar energy and that there are both positive and negative parts to the system com- pared to conventional ramp irrigation. The potential system has, for example, both a higher cost which was 1.1 times higher, and a higher energy requirement per hectare which was 5 times higher compared to a conventional system. However, the potential system performed better compared to a conventional system concerning climate impact which was 10 times lower compared to a conven- tional system. The SWOT summarize also showed that interest in automated irrigation systems was low among farmers partly due to the systems not being adapted to Swedish conditions and the large investment cost. Thus it is necessary that more actors be involved and the knowledge spread to increase the establishment of automated irrigation systems in southern Gotland (Storsudret) and in the rest of Sweden.

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