Dissertations / Theses on the topic 'Hydroponics'

Hydroponics is a method of cultivating plants without the use of soil. Soil acts as a growth medium which gives plants stability, provides nutrients and allows roots to be kept wet without drowning. In hydroponics the soil’s functions are replaced by synthesized methods. Stability comes from a substrate (i.e. LECA, rockwool perlite).The 16 essential nutrients are solved in water which are distributed to plants’ roots by different techniques. To generate photosynthesis natural light is replaced by artificial light, especially red light in the proximity of 660 nm. Hydroponics has been used as a cultivation method for at least 2000 years. During the 20th century industrial applications became common since plastics allowed for complex systems engineering. The method also makes it possible to grow the same amount of crops with approximately 10% water usage and 25% of the area compared to conventional cultivation. During the past few years systems for home use has emerged but the product genre is still in its cradle. This master thesis covers a new conceptual design of a hydroponic home system. The project was carried out at Omecon AB in Stockholm as a consulting design project. Omecon AB is an engineering consultant agency within mostly mechanical construction looking to widen the competence base. Using a design process based on Human-Centered Design the project involved the stakeholders users, extreme users, Omecon AB, plant experts, electronics engineering and service as well as plastics design engineering. Additional/supplemental economical–, ecological– and social sustainability aspects has been considered during all phases of the process. By using the Human-Centered Design process the problem range is expanded from its initial state which results in a more complete end result. Common methodology altered with some unorthodox twists has been utilized throughout the project. The final result is a conceptual hydroponic system for home environment which is designed as an interior design product as well as a high-performance cultivation system. By using natural materials such as wood and steel the users expands its life span and thus mitigates the negative environmental impact. Another aspect which prolongs the products life span is the modular usage which lets users vary and choose their preferred settings. All manufactured materials included in the final concept were flow resources and the parts were engineered to be easily separable for future replacement and recycling. A new type of pot was invented along with a new way of adjusting the height-wise position of lamps. The aeroponic technique, which was applied to this concept, is generally considered to generate the largest plants and thus comprises higher performance compared to other home systems. The use of substrate was also eliminated which decreases continous material consumption within hydroponics.
Hydroponik är en metod för att odla växter utan jord. Jord i odling agerar som ett växtmedium som ger plantor stabilitet, tillför näringsämnen och tillåter rötter att vara i väta utan att dränka dem. I hydroponik ersätts jordens funktioner med syntetiska metoder. Stabilitet ges av ett substrat (t.ex. LECA-kulor, stenull eller perlit). De 16 essentiella näringsämnena löses i vatten och distribueras till plantors rötter med hjälp av olika tekniker. For att skapa fotosyntes ersätts naturligt ljus med artificiellt ljus. Speciellt rött ljus i närheten av 660 nm. Hydroponik har använts som odlingsmetod i åtminstånde 2000 år. Under 1900-talet blev industiella applikationer vanliga eftersom plast möjliggjorde tillverkling av komplexa system. Metoden tillåter även att odla samma mängd grödor med 10% av vattenmängden och 25% av ytan jämfört med konventionell odling. Under de senaste åren har system avsedda för användning hemma blivit vanligare men produktgenren är fortfarande ung. Det här examensarbetet täcker en ny konceptuell design av ett hydroponiskt system för hemmabruk. Projektet utfördes på Omecon AB i Stockholm som ett konsultarbete inom design. Omecon AB är en konsultfirma som mestadels är verksamma inom mekanikkonstruktion men de vill vidga sin kompetens. Genom användning av en designprocess som har baserats på Human-Centered Design har projektet involverat intressenterna användare, extrema användare, Omecon AB, växtexperter, en elektronikingenjör samt plastkonstruktion. Vidare har aspekter inom ekonomisk–, ekologisk– och social hållbarhet beaktats genom alla faser av processen. Via användning av Human-Centered Design-processen har problemrummet expanderats från den initiala utgångspunkten vilket resulterar i ett mer komplett slutresultat. Vanlig metodik varvat med okonventionella anpassningar har använts genom projektet. Slutresultatet består av ett konceptuellt hydroponiskt system för hemmabruk som är designat som en inredningsprodukt samt ett odlingssystem med hög prestanda. Genom användning av naturliga material som trä och stål förlänger användarna produktens livslängd och på så sätt förmildras den negativa klimatpåverkan. En annan aspekt som förlänger produktens livslängd är moduläriteten som låter användare variera och välja deras föredragna inställningar. Alla tillverkade material inkluderade i slutkonceptet var flödesresurser och delarna konstruerades så att de går lätt att separera för framtida ersättning och återvinning. En ny typ av kruka uppfanns tillsammans med ett nytt sätt att justera höjden av lamporna. Den aeroponiska tekniken, som används is konceptet, är allmänt ansedd att generera de största plantorna och innefattar därför högre prestanda jämfört med andra hydroponiska hemmasystem. Användning av substrat eliminerades också vilket minskar kontinuerlig materialkonsumption inom hydroponik.

Research in the field of hydroponics from the second half of 20th century and 21st century described how the components of hydroponic systems are related to each other and established a basis for construction and operation of complex and reliable systems of hydroponic agriculture. These systems are predominantly constructed as means for mass production in agriculture or are built by individuals to be used in their garden or greenhouse. The role of design in production of these devices is rather limited. The goal of this work is to introduce hydroponics as a complex system of many interconnected parameters and to assess hydroponic systems from the perspective of design. The objective is to design such a solution that would incorporate all the elements that make up a hydroponic system and design itself. This design ought to respect not only the need to provide a suitable environment for plant growth but also the need of efficiency, ergonomics and design.

Projektet gick ut på att skapa ett system för att automatisera en hydroponisk odling, ta fram vilka storheter som är intressanta att mäta och sedan skapa elektronik för det. Det var snabbt tydligt att det är elektrisk konduktivitet (EC), pH och temperatur som är intressant att mäta. EC är ett estimat över näringsinnehållet i vattnet, pH i vattnet måste vara i rätt nivå för att växterna ska kunna ta upp näringen och temperaturen måste vara inom rätt område för att växterna ska växa. Sensorerna som valdes fungerar väldigt olika och därför skapades olika kretsar för vardera sensor. EC och temperatursensorn fick även två olika kretsar för att kunna utvärdera vilken metod som har fungerat bäst. Kretsarna skapades i en simulator och när de gav önskvärt beteende konstruerades ett PCB utifrån simuleringsritningarna. En mikrokontroller användes för att styra kretsarna och hantera mätdata för att sedan skicka det vidare till en Raspberry Pi för att skriva ut värden på en skärm. Resultaten som kretsarna gav i slutändan är tillfredställande och mycket väl inom noggrannheten som en hydroponisk odling kräver.
The project was to create a system for automating hydroponic cultivation, identifying the quantities that are relevant to measure and then creating electronics for it. It quickly became clear that it is electrical conductivity (EC), pH and temperature that are relevant to measure. EC is an estimate of the nutrient content of the water, the pH of the water must be at the right level for the plants to absorb the nutrients and the temperature must be within a certain range for the plants to grow. The sensors selected work very differently and therefore different circuits were designed for each sensor. The EC and the temperature sensor were also given two different circuits in order to evaluate which method was best suited. The circuits were designed in a simulator and when they provided desirable behaviour, a PCB was designed based on the simulation schematics. A microcontroller was used to control the circuits and manage the measurement data and then pass it on to a Raspberry Pi in order to display values ​​on a screen. The results that the circuits ultimately gave are satisfactory and very well within the accuracy required by hydroponic cultivation.

This thesis has been written for Hollbium AB, a Stockholm based Startup that provides a system called the Loop that grows edible plants in office spaces. This degree project reviews literature on hydroponics systems and design formanufacturing (DFM). The reviewed material alongside identified needs from the stakeholders serve as input for the design of an electronics board that controls The Loop.
Denna masteruppsats har skrivits för Hollbium AB:s räkning, ett Stockholmsbaserat startupföretag som levererar ett system kallat The Loop vars syfte är att odla ätbara växter i kontorsmiljö. Det här examensarbetet har innefattat granskning av litteratur relaterat till hydroponiksystem samt design för tillverkning (DFM). Den granskade litteraturen i kombination med av intressenterna identifierade behov har legat till grund för utformningen av ett elektroniksystem för styrning av The Loop.

The purpose of this project is to create a fully automatedgreenhouse that can produce year-round crops, using sensorsand actuators. Temperature in both water and air,relative humidity, water level, nutrient level and pH are allmeasured with different sensors. Though only water level,pH and nutrients will be regulated. The greenhouse will berelying on a hydroponic growing technique, meaning thatthe growing is soil-less and will be done in water. Thismakes measuring and controlling said levels easier and alsominimizes water waste and makes for a more environmentalsystem. The main focus of this project is on regulating pHand nutrient levels of the water. The system has shown tobe stable and self regulating within the desired intervals fornutrient concentration and pH for growing basil.
Syftet med det här projektet är att skapa ett automatiserat växthus som kan producera grödor året runt med hjälp av sensorer och aktuatorer. Med olika sensorer mäts temperaturen i både vattnet och luften, relativa luftfuktigheten, vattennivå, pH- och näringsvärden. Dock kommer endast vattennivå, pH- och näringsvärden regleras. Växthuset använder sig av så kallad hydroponisk odling, vilket innebär att odlingen inte sker i jord utan i vatten. Detta underlättar bland annat mätningar och kontrollering av systemet men minimerar även vattenkonsumptionen och bidrar till ett mera miljövänligt system. Projektet kommer i huvudsak inrikta sig på reglering av pH och näringsnivåer av vattnet. Systemet har visats stabilt och har förmågan att reglera sig självt inom önskat intervall för näringskoncentration och pH för att odla basilika.

As human population increases, the need for water increases in domestic, agricultural, industrial and urban sectors. Wastewater reuse after treatment is gaining acceptance world wide, as availability of fresh water sources decreases. However, it is also important to point out social and cultural differences that still exist in different pars of the world including those where reuse of wastewater for food production or any domestic use is not yet acceptable. The major concerns with effluent reuse are primarily its impact on human health and environmental risk. As a result, effluent reuse should be undertaken with caution after careful consideration of the potential impacts and risks. This thesis examined the potential to use the hydroponics nutrient film technique to grow commercially important crops using secondary-treated domestic wastewater. The crops chosen were a fruit crop (Lycopersicon esculantum - tomato), a leafy crop (Beta vulgaris ssp. cicla - silver beet) and a flower crop (Dianthus caryophyllus - carnation). Secondary-treated domestic wastewater was chosen because of the reduced risk of pathogen and heavy metal contamination in the crops and due to the guideline requirements for use of treated effluent for food crops. The possibility of using the effluent after the hydroponics treatment for further irrigation was also studied. The ability of secondary-treated effluent to supply adequate nutrients to the crops was assessed relative to a commercially available hydroponics solution (Chapter 3). The amount of time the solution was left in the system (nutrient solution retention time) was dependant on the plant uptake of the solution. The results obtained showed that the nutrients in secondary treated effluent was adequate for the carnations, but not for the food crops. The food crops from both treatments were compared to the produce purchased from a supermarket. The food crops showed signs of nutrient deficiency, particularly nitrogen. Based on the findings of the first experiment, the nutrient solution retention time was amended to 14 days. The carnations were not tested with the shorter nutrient solution retention time (NSRT) because they performed well in the previous trial with the longer nutrient solution retention time. The edible food crops performed better and did not show signs of nutrient deficiency when the nutrient solution retention time was reduced to 14 days. Further statistical analysis was conducted with the data from Chapters 3 and 4. Nutrient and water balances were calculated and the possible reason that the plants grown in the 14-day nutrient solution retention time took up more water, was a result of increased nutrients and better growth. A simple model was constructed to calculate height of the plants using multiple regression. The model was validated against the data collected from this study. The experiment conducted in Chapter 6 determined the nutritional quality of the food crops. The harvests from the wastewater and commercially available hydroponics solution were compared to produce purchased from a supermarket and tested for total caroteniods, total soluble solids and ascorbic acid concentrations. The nutritional quality of the wastewater grown produce was comparable to those grown in the hydroponic solution and those purchased. The risk of pathogen contamination to food crops and the die-off of pathogens in the hydroponic channels were studied in Chapter 7. This was tested by spiking the commercial hydroponic medium with Escherichia coli and Salmonella typhimurium and monitoring bacterial pathogen die-off in the secondary treated domestic wastewater. The pathogen quality of the crop was tested in all treatments as well as on organically grown produce found at a local supermarket. The results of this experiment did not show any contamination on the surface of the food crops or within the food crops. This study demonstrated that growing tomatoes, silver beet and carnations using secondary-treated domestic wastewater was successful when the nutrient solution retention time was adjusted to the optimum level. In arid, developing and remote communities, this system is ideal as it conserves and reuses water for commercially important crops without compromising the health of the environment or of human beings. It can also be implemented in urban areas, as the system can be scaled according to the availability of space. In addition to this, the effluent after going through this system can be used for open irrigation as it meets the World Health Organisation guidelines. However, a number of additional concerns need further investigation. They include the transmission risk of other types of pathogen, which depends on the source of wastewater, and the effects of hormones and antibiotics on food crops and their effect on human health.

As human population increases, the need for water increases in domestic, agricultural, industrial and urban sectors. Wastewater reuse after treatment is gaining acceptance world wide, as availability of fresh water sources decreases. However, it is also important to point out social and cultural differences that still exist in different pars of the world including those where reuse of wastewater for food production or any domestic use is not yet acceptable. The major concerns with effluent reuse are primarily its impact on human health and environmental risk. As a result, effluent reuse should be undertaken with caution after careful consideration of the potential impacts and risks. This thesis examined the potential to use the hydroponics nutrient film technique to grow commercially important crops using secondary-treated domestic wastewater. The crops chosen were a fruit crop (Lycopersicon esculantum - tomato), a leafy crop (Beta vulgaris ssp. cicla - silver beet) and a flower crop (Dianthus caryophyllus - carnation). Secondary-treated domestic wastewater was chosen because of the reduced risk of pathogen and heavy metal contamination in the crops and due to the guideline requirements for use of treated effluent for food crops. The possibility of using the effluent after the hydroponics treatment for further irrigation was also studied. The ability of secondary-treated effluent to supply adequate nutrients to the crops was assessed relative to a commercially available hydroponics solution (Chapter 3). The amount of time the solution was left in the system (nutrient solution retention time) was dependant on the plant uptake of the solution. The results obtained showed that the nutrients in secondary treated effluent was adequate for the carnations, but not for the food crops. The food crops from both treatments were compared to the produce purchased from a supermarket. The food crops showed signs of nutrient deficiency, particularly nitrogen. Based on the findings of the first experiment, the nutrient solution retention time was amended to 14 days. The carnations were not tested with the shorter nutrient solution retention time (NSRT) because they performed well in the previous trial with the longer nutrient solution retention time. The edible food crops performed better and did not show signs of nutrient deficiency when the nutrient solution retention time was reduced to 14 days. Further statistical analysis was conducted with the data from Chapters 3 and 4. Nutrient and water balances were calculated and the possible reason that the plants grown in the 14-day nutrient solution retention time took up more water, was a result of increased nutrients and better growth. A simple model was constructed to calculate height of the plants using multiple regression. The model was validated against the data collected from this study. The experiment conducted in Chapter 6 determined the nutritional quality of the food crops. The harvests from the wastewater and commercially available hydroponics solution were compared to produce purchased from a supermarket and tested for total caroteniods, total soluble solids and ascorbic acid concentrations. The nutritional quality of the wastewater grown produce was comparable to those grown in the hydroponic solution and those purchased. The risk of pathogen contamination to food crops and the die-off of pathogens in the hydroponic channels were studied in Chapter 7. This was tested by spiking the commercial hydroponic medium with Escherichia coli and Salmonella typhimurium and monitoring bacterial pathogen die-off in the secondary treated domestic wastewater. The pathogen quality of the crop was tested in all treatments as well as on organically grown produce found at a local supermarket. The results of this experiment did not show any contamination on the surface of the food crops or within the food crops. This study demonstrated that growing tomatoes, silver beet and carnations using secondary-treated domestic wastewater was successful when the nutrient solution retention time was adjusted to the optimum level. In arid, developing and remote communities, this system is ideal as it conserves and reuses water for commercially important crops without compromising the health of the environment or of human beings. It can also be implemented in urban areas, as the system can be scaled according to the availability of space. In addition to this, the effluent after going through this system can be used for open irrigation as it meets the World Health Organisation guidelines. However, a number of additional concerns need further investigation. They include the transmission risk of other types of pathogen, which depends on the source of wastewater, and the effects of hormones and antibiotics on food crops and their effect on human health.

As human population increases, the need for water increases in domestic, agricultural, industrial and urban sectors. Wastewater reuse after treatment is gaining acceptance world wide, as availability of fresh water sources decreases. However, it is also important to point out social and cultural differences that still exist in different pars of the world including those where reuse of wastewater for food production or any domestic use is not yet acceptable. The major concerns with effluent reuse are primarily its impact on human health and environmental risk. As a result, effluent reuse should be undertaken with caution after careful consideration of the potential impacts and risks. This thesis examined the potential to use the hydroponics nutrient film technique to grow commercially important crops using secondary-treated domestic wastewater. The crops chosen were a fruit crop (Lycopersicon esculantum - tomato), a leafy crop (Beta vulgaris ssp. cicla - silver beet) and a flower crop (Dianthus caryophyllus - carnation). Secondary-treated domestic wastewater was chosen because of the reduced risk of pathogen and heavy metal contamination in the crops and due to the guideline requirements for use of treated effluent for food crops. The possibility of using the effluent after the hydroponics treatment for further irrigation was also studied. The ability of secondary-treated effluent to supply adequate nutrients to the crops was assessed relative to a commercially available hydroponics solution (Chapter 3). The amount of time the solution was left in the system (nutrient solution retention time) was dependant on the plant uptake of the solution. The results obtained showed that the nutrients in secondary treated effluent was adequate for the carnations, but not for the food crops. The food crops from both treatments were compared to the produce purchased from a supermarket. The food crops showed signs of nutrient deficiency, particularly nitrogen. Based on the findings of the first experiment, the nutrient solution retention time was amended to 14 days. The carnations were not tested with the shorter nutrient solution retention time (NSRT) because they performed well in the previous trial with the longer nutrient solution retention time. The edible food crops performed better and did not show signs of nutrient deficiency when the nutrient solution retention time was reduced to 14 days. Further statistical analysis was conducted with the data from Chapters 3 and 4. Nutrient and water balances were calculated and the possible reason that the plants grown in the 14-day nutrient solution retention time took up more water, was a result of increased nutrients and better growth. A simple model was constructed to calculate height of the plants using multiple regression. The model was validated against the data collected from this study. The experiment conducted in Chapter 6 determined the nutritional quality of the food crops. The harvests from the wastewater and commercially available hydroponics solution were compared to produce purchased from a supermarket and tested for total caroteniods, total soluble solids and ascorbic acid concentrations. The nutritional quality of the wastewater grown produce was comparable to those grown in the hydroponic solution and those purchased. The risk of pathogen contamination to food crops and the die-off of pathogens in the hydroponic channels were studied in Chapter 7. This was tested by spiking the commercial hydroponic medium with Escherichia coli and Salmonella typhimurium and monitoring bacterial pathogen die-off in the secondary treated domestic wastewater. The pathogen quality of the crop was tested in all treatments as well as on organically grown produce found at a local supermarket. The results of this experiment did not show any contamination on the surface of the food crops or within the food crops. This study demonstrated that growing tomatoes, silver beet and carnations using secondary-treated domestic wastewater was successful when the nutrient solution retention time was adjusted to the optimum level. In arid, developing and remote communities, this system is ideal as it conserves and reuses water for commercially important crops without compromising the health of the environment or of human beings. It can also be implemented in urban areas, as the system can be scaled according to the availability of space. In addition to this, the effluent after going through this system can be used for open irrigation as it meets the World Health Organisation guidelines. However, a number of additional concerns need further investigation. They include the transmission risk of other types of pathogen, which depends on the source of wastewater, and the effects of hormones and antibiotics on food crops and their effect on human health.

Despite millions of Rands being disbursed to the three hydroponic projects in the Nelson Mandela Bay Municipality by Provincial Departments, Development Agencies and NGOs, relatively little is known about the impact of these projects. There is too little evaluative research on the effectiveness of such development projects. Questions arose as to what made these projects fail and what was required for sustainability over their intended life-spans. Evaluations assess a project’s ability to be sustained by examining different aspects of sustainability, including technical soundness, skills transfer, political effect, economic viability, and institutional, organizational and management effectiveness. This study has revealed that hydroponic production is a very challenging business that requires close monitoring, intense technical knowledge, and continuous learning. Moreover it is very costly, while profit generation is quick and the market central for the sustainability of this kind of project. The findings of this study also revealed that no proper feasibility study was conducted including selection of beneficiaries, no monitoring by funders and donors, no transfer of skills and no continuous empowerment of project members. Project members also indicated that they are aware of the causes of their project closures and that they are willing to participate in hydroponics production initiatives again because of the potential that these projects have.

The world’s population is growing at an average of 1.2 percent per annum and forecasts see the global population reaching 9.6 billion by 2050. This places great demands on the sustained production capacity of agricultural organisations to meet the desperate need for nutrition. This problem will continue to persist if production methods do not evolve to improve production and quality. Hydroponics and Controlled Environment Agriculture (CEA) was first seen in Rome during the 1st Century. Then sixteen Centuries later Greenhouses were developed in France and England as experimental hydroponics for basic laboratory research. Rapid expansion took place from about the 1950’s in areas where traditional openenvironment agriculture was difficult or impossible such as the deserts of Iran, Abu Dhabi and California. Sixty-five years later in 2015 hydroponics and CEA are well established around the world with thousands of hectares under propagation. Hydroponics is a method of agricultural production that has been refined over the years to become an exact science. Through the application of technology and know-how the physiological processes within plants can be manipulated and controlled to produce superior results. These results require less land area and less water to accomplish. It can be seen, based on this development, that hydroponics is such an evolution that has the capacity to meet the needs of a growing global population and its nutritional needs. The challenge lies, though, in the scientific understanding and application of knowledge in growing and managing a hydroponics farm. This study seeks to determine the internal data and external information needs of farmers in the hydroponics industry. This data and information will be integrated into a Farm Management Information System (FMIS) model that will be used for decision making, report generation and documentation. The problem leading to this study is the dissemination of data and information sources that are currently underutilised and difficult to access. In determining the internal data and external information needs, an empirical study was conducted using structured interview. Thirty farm managers were interviewed to assess what their current information system consisted of, whether they had a need for an FMIS and what internal data and external information was needed which related to four functional components of hydroponic farming. The results of this study indicate that there is a need for an FMIS for the hydroponic industry in South Africa. The results also indicate that managers are not fully satisfied with the performance of their current information system and would be interested in considering alternative information systems. Data points relating to the four functional components were assessed and integrated into an FMIS model for the hydroponic industry. This model sets out to integrate internal data and external information for purposes of decision making, report generation and documentation.

This thesis deals with the history of a method of plants cultivation without original substrate. The method is hydroponics and its subsequent development is called aeroponics. This work outlines the design of the whole aeroponic system including a control unit. The control unit has been designed to control the injection of nutrient solution, which is essential to the life of plants.Further, the control unit performs the control of lighting period, temperature, air flow and also regulation of nutrient solution pH. The control unit also keeps records of all data necessary for the monitoring process and for the evaluation of time differencies in the system.

Experiments were conducted with tomato under shade netting and with lettuce in a vertical hydroponic system at the Hatfield Experimental Farm, University of Pretoria. The objectives of the study were: 1. To evaluate the effect of different types of shade netting on tomato production 2. To develop a vertical hydroponic system for lettuce production which would be suitable for use by small-scale farmers. In the tomato trial the highest number of fruit per plant (47) was produced under 12% white shade and 40% black shade nets, and the lowest fruit number (35) was produced under 30% black net. The highest yield of 6.2 kg per plant was obtained under the 18% white net while 30% black net produced the lowest yield of 3.9 kg per plant. The test yield of lettuce grown in plastic tubes with eight vertically arranged plant positions were obtained with a continuous high flow rate of the nutrient solution. However, a simplified manual system where the nutrient solution was delivered by gravity from a small reservoir tank resulted in comparable yields.
Dissertation (M Inst Agrar (Agronomy))--University of Pretoria, 2007.
Plant Production and Soil Science
unrestricted

The collaboration between the University of Barcelona and Acciona Agua was focused on optimizing greenhouses hydric resources. The functionality of a combined treatment had to be assessed, when applied to the discard stream of a recycling system of the Advanced Greenhouse leachates. The coupling consisted on an Advanced Oxidation Processes (AOP), photo-Fenton, based on hydroxyl radical oxidative potential, produced by the interaction between Fe2+ and H2O2, and a slow sand filtration column acting as a bioreactor. The recycling system will require the synergy of chemical and biological processes to be able to work efficiently with the particular characteristics of greenhouses effluents: high salinity content and the presence of pesticides. Two recycling strategies proposed by the project defined two conductivity thresholds that the coupled system should be able to cope with. The first strategy proposed a simple semi-closed system that recycled nutrient solution from the hydroponics crops until a maximum value of 11 mS•cm(-1), phytotoxicity limit. Part of the current was then diverted to be treated by the integrated system. The second strategy introduced reverse osmosis membrane technology that concentrated that diverted stream, sending the permeate for its reuse directly to the greenhouse, while the brine had to be treated by the coupled process. In this case the maximum level of salinity in the effluents could reach conductivities close to those for seawater, around 50 mS•cm(-1). The performance of photo-Fenton reaction was essayed in order to improve the knowledge regarding this treatment technique. On the first place, this AOP and the ozonation process were compared. Results shown that increasing toxicity of ozonation effluents confirmed the choice of photo-Fenton as the most adequate treatment for pesticide polluted effluents. Experimental design criteria allowed then to determine optimal working conditions depending on the content of the reaction media, and enabled to prove the existence of endogenous catalyst inhibition in the presence of fosetyl-Al. Salinity essays were finally performed, yielding positive results even for highest conductivity effluents. Those positive results were also reflected in the increase of the biodegradability of the treated effluents, what leaded to the next step of the research. Biocompatibility of pretreated effluents was essayed by means of sequencing batch reactors (SBR). These devices were used to show how photo-Fenton indeed increased biodegradability of the effluents, and how it grown until a certain point when more hydrogen peroxide did not lead to better results. They were also utilized to assess the biocompatibility of high salinity pretreated effluents, as a first step towards the coupling with the slow sand filtration at high conductivities. Results obtained were extremely encouraging, given that even for the highest salinity concentrations (10 and 50 mS•cm(-1)), the performance of the bioreactor achieved an organic content reduction for more than 80% of the loaded concentration, which compared to the 10-20% removal achieved by photo-Fenton, justifies the need of combining both treatments. Guided by those positive results, the load of the slow sand filtration column with different salinity pretreated effluents was performed. Also positive results were obtained. The achieved elimination of the organic content was more than 75% when loaded with 10 mS•cm-1 effluent, and the refractory fraction (the remaining organic matter that cannot be oxidized either by photo-Fenton reaction or by the biomass metabolism) was the lowest also for this high conductivity. Molecular biology tools, MTBs, used in this thesis were based on cloning and sequencing techniques of 16S rRNA genes. They allowed characterizing the bacterial population of one of the assessed SBRs and of the different loading stages of the slow sand filtration column. They showed how with the increase of salinity, the population in the slow sand filtration column loosed diversity, despite the fact that the performance of the column was still proficient. This fact stated how a very different microbial consortium could be developing the same functions as others. According to obtained results, it could be finally concluded that the coupling between photo-Fenton reaction and slow sand filtration column could be an effective treatment alternative for implementing the recycling strategies of hydroponics greenhouse leachates proposed by CENIT-MEDIODIA Project. For its part, MBTs were revealed as powerful tools to characterize microbial population and increase the understanding of the bioreactions taking part in bioremediation.
Esta tesis se enmarca en la colaboración entre el Departamento de Ingeniería Química de la Universidad de Barcelona y el Departamento de I+D de Acciona Agua S.A.U, en el marco del Proyecto CENIT- MEDIODIA (2007-2010). Esta iniciativa la componen un consorcio de empresas un consorcio de empresas y centros de investigación que unieron esfuerzos de innovación en el desarrollo de un nuevo concepto de Invernaderos Hidropónicos Avanzados. La colaboración entre la Universidad de Barcelona y Acciona Agua se centró en la optimización de los recursos hídricos de dichos invernaderos. Así se evaluó la funcionalidad de un tratamiento combinado que integrara un Proceso de Oxidación Avanzada (reacción foto-Fenton), y un reactor biológico (columna de arena de filtración lenta), aplicados a la corriente de desecho de un sistema de recirculación de lixiviados provenientes del nombrado invernadero avanzado. Las particularidades de dicho sistema de reciclado harían que el sistema combinado tuviese que trabajar con efluentes con alto contenido en pesticidas (metomilo, imidacloprid y fosetyl-Al, fueron escogidos para simular los lixiviados de invernadero) y conductividades entre 11 y 50 mS•cm-1. De este modo el principal objetivo del proceso integrado sería el de conseguir la máxima eliminación de los compuestos xenobióticos y de la carga orgánica que los acompañe en el efluente tratado. Así pues, la experimentación se llevó a cabo frente a tres aspectos relacionados con el sistema combinado: estudio de la reacción foto-Fenton, ensayos con biorreactores, y empleo de herramientas de biología molecular (MBT, en sus siglas en inglés) aplicadas a la caracterización de la biomasa desarrollada en los biorreactores ensayados. Según los resultados obtenidos, se llegó a la conclusión de que la combinación de la reacción foto-Fenton y la columna de filtración lenta podría ser una alternativa de tratamiento eficaz para la aplicación de las estrategias de reciclaje de los lixiviados hidroponía presentadas en Proyecto CENIT-MEDIODIA. Además, MBT se revelaron como poderosas herramientas para caracterizar la población microbiana de distintos biorreactores y las funciones que desempeñan.

Conventional end-of-pipe solutions for wastewater treatment have been criticized from a sustainable view-point, in particular regarding recycling of nutrients. The integration of hydroponic cultivation into a wastewater treatment system has been proposed as an ecological alternative, where nutrients can be removed from the wastewater through plant uptake; however, cultivation of plants in a temperate climate, such as Sweden, implies that additional energy is needed during the colder and darker period. Thus, treatment capacity, additional energy usage and potential value of products are important aspects considering the applicability of hydroponic wastewater treatment in Sweden.

To enable the investigation of hydroponic wastewater treatment, a pilot plant was constructed in a greenhouse located at Överjärva gård, Solna, Sweden. The pilot plant consisted of several steps, including conventional biological processes, hydroponics, algal treatment and sand filters. The system treated around 0.56-0.85 m3 domestic wastewater from the Överjärva gård area per day. The experimental protocol, performed in an average of twice per week over a period of three years, included analysis and measurements of water quality and physical parameters. In addition, two studies were performed when daily samples were analysed during a period of two-three weeks. Furthermore, the removal of pathogens in the system, and the microbial composition in the first hydroponic tank were investigated.

Inflow concentrations were in an average of around 475 mg COD/L, 100 mg Tot-N/L and 12 mg Tot-P/L. The results show that 85-90% of COD was removed in the system. Complete nitrification was achieved in the hydroponic tanks. Denitrification, by means of pre-denitrification, occurred in the first anoxic tank. With a recycle ratio of 2.26, the achieved nitrogen removal in the system was around 72%. Approximately 4% of the removed amount of nitrogen was credited to plant uptake during the active growth period. Phosphorus was removed by adsorption in the anoxic tank and sand filters, natural chemical precipitation in the algal step induced by the high pH, and assimilation in plants, bacteria and algae. The main removal occurred in the algal step. In total, 47% of the amount of phosphorus was removed. Significant recycling of nitrogen and phosphorus through harvested biomass has not been shown. The indicators analysed for pathogen removal showed an achieved effluent quality comparable to, or better than, for conventional secondary treatment. The microbial composition was comparable to other nitrifying biological systems. The most abundant phyla were Betaproteobacteria and Planctomycetes.

In Sweden, a hydroponic system is restricted to greenhouse applications, and the necessary amount of additional energy is related to geographic location. In conclusion, hydroponic systems are not recommended too far north, unless products are identified that will justify the increased energy usage. The potential for hydroponic treatment systems in Sweden lies in small decentralized systems where the greenness of the system and the possible products are considered as advantages for the users.

Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains xiii, 178 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 112-115).

It is becoming increasingly evident that agriculture is playing a pivotal role in the socio-economic development of South Africa. The agricultural sector is important because it contributes approximately 2% to the gross domestic product of the country. However, many factors impact on the sustainability of traditional agriculture in South Africa. Unpredictable climatic conditions, land degradation and a lack of information and awareness of innovative farming solutions are among the factors plaguing the South African agricultural landscape. Various farming techniques have been looked at in order to mitigate these challenges. Among these interventions are the introduction of organic agriculture, greenhouse agriculture and hydroponic agriculture, which is the focus area of this study. Hydroponic agriculture is a method of precision agriculture where plants are grown in a mineral nutrient solution instead labour- intensive activity that requires an incessant monitoring of the farm environment in order to ensure a successful harvest. Hydroponic agriculture, however, presents a number of challenges that can be mitigated by leveraging the recent mobile Information and Communication Technologies (ICTs) breakthroughs. This dissertation reports on the development of a wireless ICT monitoring application for hydroponic agriculture: HydroWatcher mobile app. HydroWatcher is a complex system that is composed of several interlacing parts and this study will be focusing on the development of the mobile app, the front-end of the system. This focus is motivated by the fact that in such systems the front-end, being the part that the users interact with, is critical for the acceptance of the system. However, in order to design and develop any part of HydroWatcher, it is crucial to understand the context of hydroponic agriculture in South Africa. Therefore, complementary objectives of this study are to identify the critical factors that impact hydroponic agriculture as well as the challenges faced by hydroponic farmers in South Africa. Thus, it leads to the elicitation of the requirements for the design and development of HydroWatcher. This study followed a mixed methods approach, including interviews, observations, exploration of hydroponic farming, to collect the data, which will best enable the researcher to understand the activities relating to hydroponic agriculture. A qualitative content analysis was followed to analyse the data and to constitute the requirements for the system and later to assert their applicability to the mobile app. HydroWatcher proposes to couple recent advances in mobile technology development, like the Android platform, with the contemporary advances in electronics necessary for the creation of wireless sensor nodes, as well as Human Computer interaction guidelines tailored for developing countries, in order to boost the user experience.

Sustainable alternatives to using mined nutrients in agriculture must be found in order to limit environmental impacts such as eutrophication, habitat destruction and greenhouse gas emis-sions. Biogas slurry and urine recycled to hydroponic food production (a type of soilless agri-culture) have the potential of providing inorganic nitrogen and phosphorus, the main essential nutrients required for plant growth. A Life Cycle Inventory Assessment (LCI) methodology has been used to compare the systems of producing artificial fertilizer, biogas slurry and urine based nutrient solutions for the growth of Brassica rapa L. (Chinese cabbage) in the context of a large scale hydroponic vertical farm. Costs and energy requirements have been the basis of the comparison and results show that both biogas slurry and urine are considerably cheaper than the commercial alternative and based on the nutrient content they have the potential of being successful nutrient solutions after dilution and nutrient supplementation. Filtration might also be required in order to remove suspended particles and pathogens.

Thesis (MScAgric)--University of Stellenbosch, 2003.
ENGLISH ABSTRACT: An open air hydroponic production system (OHS) is based on classic hydroponic principles, with the difference that it lacks climatological control because the plants are not produced in greenhouses and are cultivated in the outside environment. In these systems the plant is provided with all the essential nutrients through the irrigation system, which is scheduled according to accurate measurements of the available soil water, in three to seven pulses a day. The rationale is that, by delivering nutrients each day, the mixes can be representative of what the plant actually requires for that specific phenological stage. The aim of this study was to monitor the usefulness and impact of OHS on table grape production within the framework of a case study. For this purpose, it was necessary that all factors involved in the development and growth of the plant should be studied and integrated in a multidisciplinary approach. Currently very limited information exists on basic guidelines for the effective implementation of these systems for table grape production, particularly with regard to local conditions. As a start, and to establish some guidelines and measurable parameters for the implementation of these systems, vegetative growth parameters were analysed within the framework of yield and fruit quality. The experiments were performed in a commercial vineyard in the Paarl region and the cultivars used were Dan ben Hannah (DBH) and Waltham Cross (WC). Relevant soil and climatic conditions, irrigation scheduling, fertiliser application, as well as cultivation practices, were taken into account. The soil maps provided information on the soil types identified in the blocks prior to the establishment of the two cultivars. The conventionally treated vines were irrigated and fertilised according to historical block data, and the OHS-treated vines according to programmes established by two different consultants. The experimental layout included a comparison of conventional cultivation methods and vines that had been switched over from conventional methods to OHS in the middle of 2000. All measurements within the different treatments were done at specific measuring points laid out statistically. Ten phenological stages were chosen to monitor the various aspects throughout the season for both cultivars treated conventionally and hydroponically. All relevant climatic parameters were collected for this specific production unit. The growth, fertility and quality indicators of these cultivars under the mentioned cultivation practices are discussed and established through quantitative analysis One of the aims, namely to show that established table grape vines could adapt from micro-irrigation to drip irrigation within two seasons in terms of root adaptation, was proven in this study. Initially the soil types were identified as Cartref, Clovellyand Glenrosa for both cultivars. The WC block contained an Avalon and the DBH a Westleigh soil type as well. The soil pits in all four treatments revealed the soil type to be a Tukulu form with differences in the clay content. Active roots developed underneath the drip lines for the OHS-treated cultivars, while the roots were still evenly distributed over the entire soil profile for the conventionally treated vines. Also, both cultivars adapted to OHS in terms of yield and production within two seasons, especially WC, which produced a higher yield in the 2001/2002 season than in the previous four seasons. DBH showed a strong vegetative reaction to OHS in terms of excessive vegetative growth, which had an indirect effect on fruit quality and bud fertility. A higher rate of bud mite infection in the OHS-treated vines also had a negative influence on bud fertility. The excessive vegetative growth was due to a rainy 2001/2002 growth season, in combination with the irrigation and fertiliser programmes. The irrigation and fertiliser programmes were changed from the 2000/2001 to the 2001/2002 season because of the change in consultants. As a result of this change, the OHS-treated vines were given very high nitrogen, phosphorus, potassium and micronutrient applications in the 2001/2002 season. The penetration of light in the canopy of the OHS-treated DBH was lower than in the conventionally treated DBH as a result of the above-mentioned factors, but the situation in Waltham Cross was the opposite. In the winter season of 2001, both OHS-treated cultivars were not fully adapted to the new system, as their pruning mass was lower than in the conventionally treated cultivars. No significant differences were determined for the winter cane starch content of both cultivars under conventional and OHS treatments. Effective fertiliser uptake proved to be suboptimal, especially in the case of calcium. Fruit analyses showed a lower calcium content in the OHS-treated fruit, which led to a poor skin cell structure and higher Botrytis infection during cold storage. The OHStreated cultivars showed more compact bunches, with an overall smaller rachis structure, which was another reason for the higher Botrytis infection during cold storage. However, the more compact rachis structure could not be explained on the basis of the elemental analyses. The OHS-treated DBH showed a more intense red berry colour, while the OHS-treated WC had a higher Fosscan Brix value. Both OHS-treated cultivars therefore ripened earlier than the conventional treatments. One of the advantages of the use of OHS in table grape production shown in this study was the ability to manipulate the phenology of the grapevine to provide fully ripened grapes a few days earlier than the conventionally treated grapes. This kind of advantage could be used to manipulate the production of table grapes for a better market window. Despite its limitations, this study concluded that the use of OHS for table grape production might be a useful tool for future production management, but that accurate management regarding irrigation and nutrient applications is a prerequisite. This will have to be developed systematically through experimentation to fully unlock the potential of the OHS management system for table grape production. This study provides a starting point for future research to elucidate these aspects and has clearly shown that even established vineyards can be switched to OHS in a relatively short period of time. It is envisaged that the advantages of this system, as long as the correct management protocols are in place, could have a positive effect on the production of high quality fruit for the international market.
AFRIKAANSE OPSOMMING: 'n Oop hidroponiese produksiestelsel (OHS) is gebaseer op klassieke hidroponiese beginsels, met die verskil dat OHS nie klimatologies beheer kan word nie. Die plante word nie in glashuise of tonnelsisteme verbou nie, maar wei onder buitelug toestande. Binne hierdie sisteme word die plante van alle noodsaaklike voedingstowwe deur die besproeiingstelsel voorsien. Hierdie voedingstowwe word in drie tot sewe pulse per dag volgens akkurate beskikbare grondwaterbepalings geskeduleer. Die rasionaal is dat, deur die daaglikse lewering van voedingstowwe, die mengsels verteenwoordigend is van die plant se behoefte vir 'n spesifieke fenologiese stadium. Die doel van die studie was om die bruikbaarheid en impak van OHS op tafeldruifproduksie binne die raamwerk van 'n gevallestudie te monitor. Alle faktore wat by die groei en ontwikkeling van die plant betrokke is, moet in 'n multidissiplinêre benadering bestudeer en geïntegreer word. Daar is tans slegs beperkte inligting oor die basiese riglyne en effektiewe implementering van dié sisteme vir tafeldruifproduksie wat spesifiek is vir plaaslike toestande. As 'n beginpunt, en om sekere riglyne en meetbare parameters vir die implementering van die sisteme te vestig, is vegetatiewe parameters binne die raamwerk van opbrengs en vrugkwaliteit geanaliseer. Alle eksperimente is in kommersiële wingerdblokke in die Paarl-omgewing uitgevoer. Die kultivars wat vir die studie gebruik is, is Dan ben Hannah (DBH) en Waltham Cross (WC). Alle relevante grond- en klimaatstoestande, sowel as besproeiingskedulering, bemestingprogramme en verbouingspraktyke is vir die projek in ag geneem. Ou grondkaarte het inligting ten opsigte van die verskillende grondtipes wat voor die vestiging van die verskillende kultivars geïdentifiseer is, verskaf. Die wingerde, onder konvensionele behandeling, is volgens historiese blokdata besproei en bemes, terwyl die wingerde onder OHS volgens geskeduleerde programme wat vanaf konsultante verkry is, besproei en bemes is. Die eksperimentele uitleg het 'n vergelyking van konvensionele verbouingsmetodes en wingerde wat in die middel van 2000 van konvensionele na OHS-verbouing oorgeskakel is, ingesluit. Alle metings en analises binne die verskillende behandelings het by spesifieke statistiesbepaalde punte plaasgevind. Tien fenologiese stadia is gekies om die verskillende aspekte vir beide kultivars onder konvensionele en OHSbehandeling gedurende die seisoen te monitor. Alle relevante klimaatsdata is vir die spesifieke produksie-eenheid aangevra. Alle groei-, vrugbaarheids- en kwaliteitsparameters van die kultivars onder die bogenoemde behandelingsmetodes is bespreek en gevolglik deur kwantitatiewe analises bepaal. Een van die doelwitte, naamlik om uit te vind of reeds gevestigde ouer wingerde in terme van wortelaanpassing binne twee seisoene kan aanpas van mikrobesproeiing na drup OHS, is deur die studie bevestig. Aanvanklik was die grondtipes geidentifiseer as die vorme, Cartref, Clovelly en Glenrosa vir beide kultivars, met 'n Avalon vorm adisioneel by WC, en 'n Westleigh vorm by die DBH. Grondprofiele het egter getoon dat die grondtipes vir al vier behandelings 'n Tukulu vorm is met verskillende klei inhoude. Aktiewe wortels het vir die OHS-behandelde wingerde onder die druppers ontwikkel, terwyl die wortels in die konvensionele behandeling steeds eweredig oor die hele grondprofiel versprei was. Beide kultivars het ook in terme van opbrengs en produksie binne twee seisoene ná die oorskakeling van die konvensionele behandeling na OHS aangepas. WC het in die 2001/2002 seisoen 'n hoër opbrengs gelewer as in die vorige vier seisoene. Afgesien van die goeie aanpasbaarheid, het DBH 'n sterk vegetatiewe groeireaksie ten opsigte van die OHS-behandeling getoon, wat 'n indirekte effek op vrugkwaliteit en oogvrugbaarheid geopenbaar het. 'n Hoër mate van knopmiet infeksie in die OHSbehandelde stokke kon ook 'n negatiewe bydrae tot oogvrugbaarheid gemaak het. Die sterk vegetatiewe groei kon aan die hoër reënval gedurende die 200112002 groeiseisoen, tesame met die besproeiings- en bemestingsprogramme, toegeskryf word. Die besproeiings- en bemestingsprogramme is verander van die 2000/2001 seisoen na die 2001/2002 seisoen weens die aanstelling van 'n ander konsultant. As gevolg van hierdie verandering het die OHS-behandelde stokke baie hoë toedienings van stikstof, fosfaat, kalium en mikroelemente in die 2001/2002 seisoen ontvang. Sonligpenetrasie in die wingerdlower van die OHS-behandelde DBH was laer as in die konvensionele behandeling as gevolg van die bogenoemde faktore. Die situasie vir WC was egter die teenoorgestelde. Tydens die winterseisoen van 2001 was beide oorgeskakelde kultivars nie ten volle by die nuwe OHS-behandeling aangepas nie, soos gesien kan word in die laer lootmassas in vergelyking met die konvensionele kultivars. Geen beduidende verskil is vir die hoeveelheid stysel in die winterlote van beide kultivars onder konvensionele en OHS-behandeling verkry nie. Effektiewe voedingstofopname was suboptimaal, veral betreffende kalsium. Vruganalises het 'n laer kalsiuminhoud in die OHS-behandelde druiwe getoon, wat aanleiding gegee het tot 'n swakker seistruktuur in die druiwedoppe en 'n hoor mate van Bottytis-infeksie gedurende koelopberging. Die OHS-behandelde kultivars het meer kompakte trosse getoon met kleiner trosraamwerke, wat ook aanleiding kon gegee het tot 'n hoër Botrytis-infeksie. Die kleiner trosraamwerke kon nie deur voedingstofanalises verklaar word nie. Die OHS-behandelde DBH het 'n hoër kleurintensiteit getoon, en die OHS-behandelde WC het 'n hoër suikerinhoud getoon ten opsigte van die konvensionele behandeling. Beide OHS-behandelde kultivars was dus vroeër ryp as die konvensionele behandelings. Een van die voordele van OHS wat uit die studie voortspruit, is die vermoë om wingerdfenologie te manipuleer om ryper druiwe vroeër in die seisoen te verkry. Hierdie tipe voordeel kan aangewend word om druiwe vir "n beter markvenster te produseer. Hierdie studie, tesame met al sy beperkinge, kom tot die gevolgtrekking dat die gebruik van OHS vir tafeldruifproduksie 'n nuttige instrument vir toekomstige produksiebestuur is, maar dat die optimale bestuur van besproeiing en bemesting as kritiese faktore beskou moet word. Hierdie faktore sal sistematies deur intensiewe navorsing ontwikkel moet word om die volle potensiaal van OHS te ontsluit, spesifiek vir tafeldruifproduksie. Hierdie studie kan as 'n beginpunt gebruik word vir toekomstige navorsing vir meer toegeligte verklarings van die bogenoemde aspekte, veral met die voordeel dat reeds gevestigde wingerde maklik en vinnig by OHS kan aanpas. Die voordele van OHS kan 'n groot positiewe invloed op die produksie van hoër kwaliteit tafeldruiwe vir die internasionale mark hê, mits die regte bestuursriglyne in plek is en toegepas word.

The use of hydroponic feeding systems for horses has gained in popularity during recent years. Typically, this feeding system allows for a more efficient use of the whole plant, including the shoot, root, and seed remnants rather than traditional grazing in which only the shoot of the plant is consumed. Vertical systems have practical uses in largely developed areas where traditional forage sources are limited, in arid countries or in areas with severe droughts where forage growth is minimal. Though there is some research on fodder utilization in production animals, there are currently no published data on the effects of fodder in horses. Our study, approved by the Southern Illinois University Institutional Animal Care and Use Committee (#13-043) utilized eight Quarter Horse mares randomly assigned to one of two diets. Control (CON) horses were offered 2% of their body weight (BW) in hay (DM) and treatment (TRT) horses received 1% of their BW in hay (DM) and 1% of BW in fresh wheat fodder (AF) twice daily. Body weight and hoof temperature data were recorded weekly. Fecal samples were collected weekly and analyzed for pH, NH3, and VFA concentration as well as DM, ash, NDF, ADF, N, CP, and EE. Hay and fodder samples were also collected weekly to monitor nutrient profiles of the two forage types for the duration of the study. Additionally, nutrient profiles from seed to mature (8 d growth) were developed for fodder. Data were analyzed as a completely randomized design using PROC MIXED of SAS (v. 9.4) and significance was established at P < 0.05. There were no significant differences in body weight, left or right front hoof temperatures between treatments. Fecal pH was significantly lower (P ≤ 0.01) in the TRT when compared to CON, and isobutyric acid was significantly (P ≤ 0.05) higher in TRT as compared to CON. A comparison of the nutrient values of the two forages demonstrated significantly higher DM, ash, NDF, and ADF (P <0.0001) in hay while N, CP, and EE (P <0.0001) were significantly higher in fodder overall. Daily growth of the fodder decreased DM content (P <0.0001) while ash, NDF, ADF, N, CP, and EE (P <0.0001) increased as the fodder reached maturity. These results indicate that utilizing fodder affects fecal metabolites associated with digestion.

Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2016.
Generally, aluminium (Al) is required as a micronutrient by plants. The metabolism of Al within the plant can exert a number of effects within the plant. These include: interfering with cell division in both root tips and lateral roots, increasing cell wall rigidity, maintaining the correct cellular redox state, as well as the various other physiological and growth responses. Al is one of the most abundant elements in the earth’s crust and becomes toxic in many plants when the concentration is greater than 2-3 ppm, where the soil has a pH<5.5. Iron (Fe) is an equally important element, and the toxicity of this metal possesses constraints primarily on wetland plants growing in acidic soils that have high reducible iron content. The impact of metal toxicity (Al and Fe) requires an understanding of many aspects related to Al and Fe uptake, transport and distribution by plants in wetland ecosystems. In this study, three species of Cyperus viz. Cyperus alternifolius, Cyperus prolifer and Cyperus textilis were used to carry out phytotoxicity tests to monitor xenobiotic substances.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第20009号
農博第2193号
新制||農||1045(附属図書館)
学位論文||H28||N5018(農学部図書室)
33105
京都大学大学院農学研究科応用生命科学専攻
(主査)教授 小川 順, 教授 阪井 康能, 教授 栗原 達夫
学位規則第4条第1項該当

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Horticulture in the Faculty of Applied Sciences at the Cape Peninsula University of Technology
The high demand for medicinal plants has favoured over-exploitation of wild plants. The search for alternative and sustainable methods of medicinal plant cultivation is imperative and desirable. Biotechnological approaches particularly hydroponic technology has the potential for large scale plant cultivation and production of secondary metabolites. The current study aims at optimizing the production of antimicrobial secondary metabolites by an indigenous South African medicinal plant species (Helichrysum cymosum) through hydroponics N and K fertilization. In Chapter 1, the conceptual framework and justifications of the study are presented. In Chapter 2 the research objective was to discern the optimal potassium (K) supplement level for H. cymosum by evaluating the effects of different hydroponic K levels on growth, K-leaf content, and anti-Fusarium oxysporum f.sp.glycines (Ascomycota: Hypocreales) and total activities. Six weeks old seedlings of H. cymosum were treated with varied concentrations of K in the form of potassium chloride, potassium nitrate and monopotassium phosphate (58.75, 117.5, 235 and 470 ppm). These concentrations were based on a modification of Hoagland’s hydroponic nutrient formula. Plants were maintained under greenhouse conditions and growth parameters (plant height and number of leaves) were recorded weekly. At 8 weeks post treatment, plants were harvested and fresh weights were recorded and tissue nutrient content analysed. Sub-samples of the aerial parts of plants grown in the different treatments were air dried, extracted with acetone and tested against F. oxysporum. Plants exposed to 235 ppm K showed a marked increase in leaf number, plant height and fresh weight. Overall there was no significant difference (P > 0.05) among the treatments with respect to tissue nutrient content; K ranged from 3.56 ± 0.198 to 4.67 ± 0.29 %. The acetone extraction yield increased with increasing K fertilization: 58.75 ppm (16.67 ± 2.35 mg), 117.5 ppm (22.5 ± 4.79 mg), 235 ppm (210 ± 38.5 mg) but dropped to 40 ± 4.08 mg at 470 ppm K. Results from the anti-F. oxysporum bioassay showed that 58.75 and 235 ppm K treatments produced the most bioactive acetone extracts; MIC values of 0.49 and 0.645 mg/l, respectively. Acetone extracts obtained from plants exposed to 235 ppm K yielded the highest total activity, comparatively (P < 0.05). In conclusion, the optimum nutrient K level for growing H. cymosum hydroponically was 235 ppm. Chapter 3 focused on another important macro nutrient N and the objective was to determine the optimum nutrient requirements for growing the medicinal plant, Helichrysum cymosum (L.) (Asteraceae), hydroponically. Experiments were conducted to assess the effects of varied nitrogen (N) concentrations supplied as nitrate and ammonium on growth, tissue nutrient content, antimicrobial and total activities of acetone extracts of aerial parts. Treatments were based on a modified Hoagland’s nutrient formula. Six week old rooted cuttings were treated with 52.5 ppm, 105 ppm, 210 ppm and 420 ppm of N. Leaf number and stem height (cm) were recorded at weekly intervals and leaf analysis conducted. The effects of N treatments on plant growth parameters varied significantly among treatments; 52.5 ppm of N yielded the tallest plants (height) [19.4 ± 0.7 cm], while 105 ppm N yielded the maximum leaf number (68.1 ± 6.2) as well as maximum fresh weight of aerial parts was obtained with 105 ppm (15.12 ± 1.68 g). Nitrogen content of plant tissue ranged between 0.53 ± 0.03 and 4.74 ± 0.29% (d, f, 3, 12; f=14; P ≤ 0.002) depending on treatments. Powdered aerial parts (5 g) of H. cymosum obtained from the different N treatments were extracted with 100 ml of acetone. N treatment significantly affected the yield of crude extracts, which ranged from 87.5 ± 15.5 (52.5 ppm) to 230 ± 23.5 mg (105 ppm). Acetone extracts of plants that were exposed to varied N treatments were screened for anti-Fusarium oxysporum activity using minimum inhibitory concentration (MIC) method. The MIC value (0.073 ± 0.014 mg/ml) obtained with acetone extracts of plants exposed to 52.5 ppm N was significantly lower compared to the MICs of the other N treatments (105 [0.47 ± 0 and 0.705 ± 0.135 mg/ml], 210 [0.234 and 0.47 mg/ml] and 420 ppm [0.29 ± 0.101 mg/ml]) at 24 and 48 hours respectively. However, the total activities of extracts obtained among the four N treatments, which ranged from 0.062 ± 0.02 to 0.26 ± 0.06 ml/g was not statistically different at 24 or 48 hours (P > 0.05). LC-MS analysis of acetone extracts of H. cymosum plants obtained from the four treatments hinted that known anti-microbial agents such as apigenin, quercetin, kaempferol, helihumulone and quinic acids were present in the extracts and the quantity of helihumulone increased with increased nutrient N level. These results suggest that H. cymosum may be cultivated hydroponically and that the antimicrobial activity and/or the phytochemical profile of the crude acetone extracts is affected by nutrient nitrogen levels. Hydroponic cultivation of plants may be able to alleviate to an extent the pressure on wild medicinal plants.

Nitrogen is the only plant nutrient taken up as both a cation (NH4 +) and anion (NO3-). Nitrate is considered the "safe" form of N and NH/ is generally thought to be toxic, especially at high levels. High NH/ /NO3- ratios are thought to be toxic because they result in a rhizosphere pH low enough to damage root membranes, induced cation deficiencies, and build-up of NH3 caused by delayed NH/ assimilation. These factors can be minimized in hydroponic culture. The objective of these studies was to quantify the effects of high NH4 + IN 0 3- ratios on nitrification and growth of wheat in hydroponics. Two cultivars of wheat (Triticum aestivum L.) were grown to maturity with either 15% or 80% of the N supplied as NH4+. The effect of using CL- versus so/- as counter ions to NH4 + was also examined. Yield was not significantly affected by NH4 + ratio or counter ion. Seed protein was increased from 15 to 19% with high NH4 +. Harvest index was reduced from 52 to 48% with 80% NH4 +, but was unaffected by counter ion. Rates of nitrification in hydroponic culture are not well quantified and could result in significant conversion of NH4+ to NO3- before plant uptake. An isotopic dilution study was conducted to quantify rates of nitrification in hydroponic culture. A 2 x 2 x 2 factorial design was used to examine the effect of pH (5.8 or 7.0), inoculation with nitrifying bacteria, and the presence of plants. This study was done with wheat grown in vigorously-aerated, 2-L bottles. Each bottle contained 10 g of diatomaceous earth to provide surface area for microbial growth. Nitrate began to accumulate in 5 din unplanted, inoculated bottles at pH 7.0; in 20 d at pH 5.8 with inoculation; but did not begin to accumulate in non-inoculated bottles (pH 5.8 or 7.0) until day 30. Nitrate never accumulated in any of the planted bottles, most likely because plants consumed the No 3- that was produced. Calculations from the isotopic dilution measurements indicated that the rate of nitrification averaged 58 μmol No 3- L-1 d-1 in the planted bottles, and averaged 270 μmol NO3- L- 1 d-1 in unplanted bottles. Nitrification was likely reduced in the planted bottles because the reduced concentration of NH4 + limited nitrification. To provide rapid, inexpensive measurement of nutrient concentration in hydroponic solution, five colorimetric tests were evaluated. Tests for NO3- and PO4 were accurate and reliable, but the tests for SO4^2-, Si 0 2, and Fe need additional refinement.

Zoospore production of Pythium dissotocum Drechs. in the nutrient solution of hydroponically-grown lettuce, in the greenhouse, was shown to be cyclic. The number of zoospores detected in the nutrient solution was lowest around noontime, (11:00-14:00 hr) and highest around 20:00 hr. Growth chamber studies were conducted to determine the effect of different light periods on zoospore production. Under continuous light or continuous darkness, the population of zoospores in the nutrient solution decreased. But under 12 hours light, and 12 hours darkness or two periods of light each for 3 hours, zoospore populations decreased during the light period but increased during the dark period.

The goal of this study was to prove that aquaponic systems can produce lettuce of equal growth and quality compared to hydroponic lettuce production and to determine the stocking density of fish required for plant growth. Aquaponics is the integration of recirculating aquaculture and hydroponic plant production. The project had four objectives. The first objective was to determine the biomass of fish required for plant growth to develop a fish to plant density ratio. The second objective was to compare lettuce grown with aquaponic water and a hydroponic solution under the same environmental conditions. The third objective was to compare the quality of lettuce grown with aquaponics water plus nutrient supplementation with a hydroponic solution. The fourth objective was to determine the nitrogen dynamics in the aquaponic system and to compare the nutrient composition of lettuce grown with aquaponics water with nutrient supplementation and hydroponic solution. It was determined that under the specified environmental conditions 5 kg m⁻³ of Nile tilapia (O. niloticus) fed 2% of their body weight daily yields on average 4.7 kg m⁻² of lettuce (L. sativa cv. Rex) in 35 days. There was no significant difference (p ≤ 0.05) in biomass or chlorophyll concentration index in lettuce (L. sativa cv. Rex) grown with aquaponics water and nutrient supplements versus a hydroponic solution. The aquaponics solution generated equal biomass and chlorophyll concentration indexes compared to the hydroponic solution. Aquaponics water plus supplementation can yield L. sativa cv. Rex with equal biomass accumulation and chlorophyll concentration indexes compared to hydroponics lettuce. Nutrients added to the aquaponics system consisted of iron, manganese, and zinc. These nutrient concentrations became depleted in the aquaponics water over time and were not replenished via the fish feed. Dolomite was added to the aquaponics system every two weeks to increase the buffering capacity of the water and maintain optimal pH levels. Aquaponics lettuce had similar nutrient composition to hydroponic lettuce. One head of L. sativa cv. Rex (176.75 ± 31.03) will assimilate approximately 5.96 grams of nitrogen (3.38% per dry gram lettuce). One kilogram of fish will yield 6.4 lettuce heads (1,128 grams) and fixate 38.13 grams of nitrogen.

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Horticulture in the Faculty of Applied Sciences at the Cape Peninsula University of Technology 2013
This study evaluated the effects of different pH levels and supplementary phosphorous concentrations on Salvia chamelaeagnea grown in hydroponics. The treatments consisted of 12 treatments of 4 differing nutrient solutions offering: low concentration of supplementary P (control), balanced concentration of supplementary P, moderate concentration of supplementary P and a high concentration of supplementary P at 3 differing pH levels. Each treatment was replicated 10 times. The objectives of this study were to asses the effect of supplementary phosphorous concentrations and 3 different pH levels on the growth, development and chlorophyll responses of Salvia chamelaeagnea grown hydroponically. Growth and development was recorded by measuring weekly heights, numbers of basal shoots, stem diameters and the number of branches, while root length and wet and dry weights of roots and shoots were measured post harvest. Chlorophyll responses were recorded by measuring weekly SPAD-502 measurements while post harvest DMSO analysis of chlorophyll A, B and total chlorophyll were recorded along with nutrient uptake levels of N, P,K, Ca, Mg, Na, Mn, Fe, Cu, Zn and B in the plant leaves. This study has shown that the use of a hydroponic nutrient system offering a moderate concentration of supplementary P at a pH level of 4 significantly influences the growth and development of Salvia chamelaeagnea grown in hydroponics. Plants treated with a pH level of 4 generally produced higher wet and dry shoot weights, root lengths, stem diameters, basal shoot numbers, branch numbers, and plant heights than that of the control and all treatments delivering nutrients at a pH level of 6 and 8. Although no one treatment offering supplementary P produced consistently high results, in most cases all the plants receiving supplementary P at a pH level of 4 outperformed the pH 6 and pH 8 treatments receiving the same amount of supplementary P. This indicates that at a pH level of 4 the mineral nutrient availability of a nutrient solution is at an adequate level for the growth and development of Salvia chamelaeagnea. Furthering studies into the effects of arbuscular mycorrhiza on the uptake of mineral nutrients, root morphology and growth and development are recommended.

Thesis (MTech (Horticultural Science))--Cape Peninsula University of Technology, 2016.
Hydroponics, i.e. plant cultivation in mineral-rich water is a synergy between plant, human, and machine. For decades the hydroponic garden has been offered on horticultural markets, and was repeatedly innovated to better meet consumer horticultural needs. Currently, platform convergences with electronic control systems can possibly enable more efficient products for direct consumer hydroponic cultivation. This means that, like many appliances in the home; hydroponic plant cultivation can become somewhat automated. Marketing and product innovation can help calibrate optimal New Product Development NPD of hydroponic gardens for people. The literature review grasps how consumers are subjected to a changing environment together with changing technology such as hydroponics, plant nutrition, and even garden automation. Market research frameworks namely Morphological Analysis (MA) and Conjoint Analysis (CA) are the tools deployed here for profiling and prioritising these products for horticultural consumers. Firstly, a qualitative analysis identifies conceptual sets for structures, inputs, and controls, which all harmonise into new intersections cultivation, hydroponics, and automation and the e-garden concepts. The MA next produces, and organises secondary data into constraints for the CA. Here, general hydroponic cultivation is first decomposed into all its many component parts which collectively describe the whole, where these parts are then classed along various attributes namely: garden plane xA, automation xB, performance xC, organics xD, and price xE So garden plane is composed of level and vertical gardens, garden automation is composed of manual and automatic gardens, garden performance is composed of casual and high-performance gardens, garden organics is composed of non-organic and organic gardens, and garden price although quantitative is simply composed of R2500 and R5000. These classes of attributed data can now become treated as categorical factors using indicator or dummy variables. Secondly, the CA determines how these attributes are most preferred by horticultural consumers at garden centre clusters. This involves measuring respondent preferences levels, to compute the part-worth utility for each attribute found in the MA. Factors such as garden organics, price, and automation hold adjusted alpha significance. Mainly, garden organics contributed to response effects, while price has negative slope and is second, while automation comes third. A combination of garden automation and organics is found to optimise consumer utility for Hydroponic Garden(s) HG.This research illuminates how horticultural consumers may prefer various HG, by understanding HG and how they can better benefit these people.

Sustained developments in light emitting diode (LED) technology have brought their irradiance to a suitable level for being considered as a replacement to traditional high pressure sodium (HPS) lamps in hydroponics growth environments. LED lamps are anticipated to replace HPS lamps in most applications due to their reduced electricity consumption, improved quality of light and the possibility for customization of the light spectrum for increased yields. While equipment costs are still high, as is the case with most new technologies, greenhouse growers across the world stand to substantially decrease their energy use which directly translates into reduced costs and reduced carbon emissions from the energy stand point. We have compared the effects of LED lamps (LED Innovation Design, TI-SL600) made by LED Innovation Design (Terrebonne, Quebec) against HPS lamps (ballast: Philips Advance Model 71A85F5; Bulb: General electric, model LU600X0PSLT40) used at HydroSerre Mirabel (Mirabel, Quebec) for the growth of Boston lettuce (Lactuca sativa var. capitata) for both biomass yields and nutrient content. The light treatments were applied for eight hours after sunset to extend the photoperiod to sixteen hours. Wet and dry masses of plants and roots were weighed on a weekly basis during the course of the experiment. On average, optimum HPS light treatment produced statistically similar masses compared to optimum LED light treatment even though the LED lamps provided roughly half the amount of moles of light per meter2 compared to the HPS lamps at final harvest time (71.3moles/m2 for HPS and 35.8moles/m2 for LED over four weeks).There was no statistical difference between the samples taken from LED and HPS optimum light treatments, regular HPS greenhouse levels and control (no supplemental light) treatment for both wet and dry masses. However, LED light treatments showed improved homogeneity of plant mass across the entire area while HPS light treatment showed potential for elevated production in limited areas. Dry ratios of plant mass (in grams) by artificial irradiation (in moles per plant) normalized by the percentage of supplemental light versus total light were of 0.54 g/mol/plant and 0.35 g/mol/plant for both HPS experimental replications and of 0.59 g/mol/plant and 0.26 g/mol/plant for both LED experimental replications. This indicates that while there is an intensity difference between both light treatments, plant mass production remained similar. Health benefits are linked with increased consumption of β-carotene and other phytochemicals present in vegetables, such as lettuce. Photomorphogenesis may enable increased concentrations of those healthy compounds at little cost to the growers. However, contrary to expected results, chemical analysis of LED-treated samples showed the smallest concentrations of β-carotene, chlorophyll a and b, neoxanthin, lutein, antheraxanthin and violaxanthin. Both control replications are significantly more concentrated in xanthophylls and chlorophylls than the samples taken from the HPS plots, which were also more concentrated than the samples harvested from LED plots. Additional research needs to be performed to optimize the LED-based photomorphogenesis process.
Les développements récent et continus dans la technologie des lampes à Diodes Électro-Luminescentes (DEL) ont permis à leur intensité d'atteindre un niveau suffisant pour être considéré comme un remplacement pour les lampes traditionnelles au sodium à haute pression (HPS) dans les environnements de croissance hydroponique. On anticipe que les lampes DEL remplaceront les lampes HPS dans la plupart des applications à cause de leur consommation réduite en électricité, de l'augmentation de la qualité de la lumière et pour les possibilités de modification du spectre lumineux pour augmenter les rendements. Bien que les coûts d'équipement soit encore élevés, comme il est le cas avec les nouvelles technologies, les producteurs en serres à travers le monde pourront réduire de façon importante leur consommation d'énergie; ce qui se traduit par une réduction des coûts et des émissions de gaz à effet de serre.Nous avons comparés des lampes DEL (LED Innovation Design, TI-SL600) faites par LED Innovation Design (Terrebonne, Québec) avec des lampes HPS (Ballaste: Philips Advance Model 71A85F5; Bulbe: General Electric, modèle LU600X0PSLT40) utilisées chez HydroSerre Mirabel (Mirabel, Québec) pour la croissance des laitues Boston (Lactuca sativa var. capitata) dans le but de déterminer le rendement de biomasse ainsi que le contenu nutritionnel des plantes. Les traitements lumineux ont été appliqués pendant huit heures après le coucher du soleil pour étendre la photopériode jusqu'à seize heures. Les masses humides et sèches des plantes et des racines ont été pesées à chaque semaine pendant l'expérience. En moyenne, le traitement optimal HPS à produit des masses statistiquement similaire à celle produite par les traitements DEL même si les lampes DEL ont produit approximativement la moitié des moles de lumières par mètre carrés comparativement aux lampes HPS (71.3moles/m2 pour HPS et 35.8moles/m2 pour DEL pendant quatre semaines).Il n'y avait pas de différence statistique entre les échantillons prélevés des traitements DEL et HPS optimaux, HPS niveau régulier et contrôle (pas de lumière supplémentaire) pour les masses sèches et humides. Par contre, le traitement DEL a démontré une homogénéité accrue de masses de plante au travers de toute la section du bassin traitée pendant que le traitement HPS a démontré un potentiel pour une production supérieure pour de petites sections localisées. Les ratios secs de masse de plante (en grammes) par l'irradiation artificielle (en moles par plante) normalisée par le pourcentage de lumière supplémentaire par rapport à la lumière totale étaient de 0.54 g/mol/plante et de 0.35 g/mol/plante pour les deux réplications HPS expérimentales et de 0.59 g/mol/plant et 0.26 g/mol/plante pour les deux réplications DEL expérimentales. Ceci indique que bien qu'il existe une différence d'intensité entre les deux traitements, la production de masse végétale reste semblable.Des bénéfices pour la santé sont reliés à la consommation de β-carotène et d'autres produits phytochimiques présent dans les légumes comme la laitue. La photomorphogenèse pourrait permettre d'augmenter la concentration de ces composés bénéfiques à peu de coûts pour les producteurs. Par contre, contrairement aux résultats attendus, l'analyse chimique des échantillons traités aux DEL démontre la plus faible des concentrations de β-carotène, chlorophylle a et b, noexanthine, lutéine, anthéraxantine et violaxanthine. Les deux réplications de contrôle sont beaucoup plus concentrées en xanthophylles et en chlorophylles que les échantillons des parcelles traitées aux lampes HPS qui étaient aussi plus concentrés que les échantillons des parcelles traitées aux lampes DEL. Des recherches additionnelles sont donc requises pour optimiser le processus de photomorphogenèse à base de lampes DEL.

Phosphorus (P) is poorly soluble in most soils and, thus, has poor plant uptake efficiency. AVAIL® and Carbond P (CBP) are new fertilizer products shown to increase P use efficiency (PUE) and increase crop yields when grown in P limiting soils. Carbond P has specifically been seen to increases P uptake and crop yields in soils low in P, although effectiveness in regards to soil organic matter is unknown. The objectives of these studies were to determine if the mode of action for these products is related to physiological response, to determine if Carbond P is toxic to plant roots when in direct contact at high rates, and determine the limitations of Carbond P in regards to biomass (yield), P uptake and concentration. We used a hydroponic study to compare CBP to AVAIL in evaluating plant toxicity and plant philological response. AVAIL and CBP were also compared to ammonium polyphosphate (APP) at pH 6 or 8 for hydroponically grown maize (Zea mays L.). Additionally, a glasshouse study evaluated the PUE of CBP with soil in which maize was grown. Soils were moderate or high in organic matter, with 0, 5, 15, 45, or 135 kg P2O5 ha-1 applied as either APP or CBP. Both studies showed that CBP is a suitable PUE enhancing fertilizer. In the greenhouse study, the high organic matter soil revealed that both CBP and APP fertilization resulted in similar increases in biomass yield and P concentration and uptake. However, in the moderate organic matter soil, biomass and total P uptake was significantly greater for CBP than APP at the two lowest P rates of fertilization and significantly higher for APP than CBP at the highest P application rate. In the hydroponic study, neither AVAIL nor CBP had any positive or adverse effects on the plants as compared to APP. These results, coupled with this and previous soil-based greenhouse and field studies with AVAIL and CBP, show that the increase in PUE is not a physiological growth stimulant response, but rather likely the result of impacts on P solubility in the soil. However, the presence of high organic matter in the soil seemed to negate the effects of the organic acid bonded P used in Carbond P. We conclude that CBP, and possibly other organic acid based fertilizers, can assist in furthering agricultural goals, as well as environmental responsibility with these known limits.

Vertical hydroponic farming is a developing sector that has the potential to mitigate the adverse effects of conventional farming while also meeting the demands of rapidly urbanizing populations. The global food system is responsible for up to 30% of anthropogenic GHG emissions, with primary production accounting for the majority of these emissions. Hydroponic farming is a type of crop production in which the plants grow without the use of soil. It is mainly done indoors. Hydroponic production has various advantages for the food system, including water efficiency, space efficiency, year-round production, and system productivity. Despite many advantages mentioned in the literature, hydroponic farming has certain drawbacks, including a reliance on electricity to grow, a limited choice of crops appropriate for hydroponic cultivation, and a higher product price.This paper examines the obstacles and describes how integrated modular farms might be implemented in Sweden to improve urban food resilience. This project aims to design a modular solution for a closed hydroponic farm using various data gathering and design methodologies. In one year, the designed hydroponic system generates about one ton of lettuce in a one-square-meter area while saving 91.27% of water compared to conventional farming methods. The secondary goal was to assess the designed system's long -term viability interms of social, environmental, and economic sustainability indicators and study the structure from an engineering standpoint.

Thesis (MTech (Horticultural Science))--Cape Peninsula University of Technology, 2016.
This aim of this study was to investigate the viability of growing P. tomentosum in deep water culture (DWC) hydroponics and to assess the effects of various methods of oxygenating the nutrient solution with regards to growth, development and chlorophyll responses. The experiment was conducted over a period of 74 days. In chapter 3, 16 different methods of oxygenation were applied to 9 replicates. The control had passive aeration. The treatments were made up of air-pumps, vortex oxygenators and the application of hydrogen peroxide (H2O2) at various frequency intervals; these were combined with each other and run as separate oxygenation methods.

Selenium (Se) is an essential element for human and livestock with antioxidant and anticancer characteristics. Although Se is not an essential element for plants, it has been reported that it can improve plant growth. This experiment was conducted at the Isfahan University of Technology in winter 2010. The experiment was factorial based on a completely randomized design (CRD) with 4 replications. Se was added to nutrient solution in 4 concentrations 2, 4, and 6 mg/l sodium selenite (Na2SeO3). Root volume, fresh and dry weights of shoots and roots, number and weight of fruits, chlorophyll content and photosynthesis traits (photosynthesis rate, stomata internal carbon dioxide (CO2) concentration, stomata conductance) were measured. Results showed that Se increased root dry weight. Fresh and dry weights of shoot increased in the 2 mg/l Se treatment and decreased at the higher level of Se. Chlorophyll content and photosynthesis rate were not affected by Se. Stomata internal CO2 concentration and stomata conductance decreased by Se addition. Overall, Se at 2 mg/l application rate was effective in some physiological characteristics of cucumber.

With a continued worldwide trend in population shift from rural to urban areas predicted to increase, new approaches to agricultural production must be considered and implemented. Little academic interest has been applied to determining economically viable urban agriculture crop production sites for business investment. A feasibility model to aid investors in selecting appropriate sites for the development of urban agriculture food production within population centers was created. Lettuce crop trials were performed from August 2015 to December 2015 at the University of Arizona Controlled Environment Agriculture Center to validate the productivity of a unique high density hydroponic system designed for the rooftop environment. The feasibility model is based on this system and with a minimal number of inputs, ranging from size of growing space to growing media costs, determines a wide range of useful outputs. These outputs include crop productivity within the facility, material inputs and a cost breakdown of starting a new agricultural venture. The model utilizes multiple sheets within one excel document to give the user a clear and organized financial perspective of a hypothetical growing operation in the main sheet. With this model, investors into urban agriculture will have a means to gain an objective view of financial considerations before substantial investment is completed.