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1
Fulcher, Amy. "MODELING WATER USE IN NURSERY CROPS". UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/121.
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Water use is an important topic in the global agriculture community and is a critical input in nursery crop production. Several plants in the genus Cornus are important nursery crops. Not only are they economically relevant, they are found in grafted and seedling forms and parents and their hybrid are readily available in the trade, facilitating an assessment of water requirements. Anecdotal information suggests that Cornus taxa have differing stress tolerance and water use requirements. Research was conducted to characterize and model water use among Cornus taxa. Scanning electron microscopy and anatomy‐based micromorphological studies as well as transpiration chamber‐based studies revealed differences in the cuticle, epidermal thickness, stomatal density, total stomatal complex area, and gas exchange. A novel photosynthesis‐based irrigation model was developed and evaluated, first on a model crop, Hibiscus rosa‐sinensis, then with a range of Cornus taxa, including grafted specimens. The model allowed the identification of a setpoint or point at which irrigation is triggered. Producing plants under this model allowed a 27% reduction in water use while maintain growth when compared with controls.
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Sedibe, Moosa Mahmood. "Optimising water use efficiency for crop production". Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53541.
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Thesis (MScAgric)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: Poor water management and poor water use efficiency (WUE) have been identified as one of the major problems experienced by vegetable growers in most of the developing countries, including South Africa. This poor management and poor utilization of water have led to a drastic decline in the quality and quantity of available water. In South Africa agriculture uses about 50% of available water. Increasing water demand for domestic, industrial and mining uses, may decrease agriculture's share to less than the current 50%, henceforth, better utilization of this resource is imperative. Selection of a good irrigation system can limit water loss considerably. Some irrigation systems have a potential to save more water than others do. Since irrigation systems affect the WUE of crops, care should be taken when selecting an irrigation system under conditions of limited water quantity. Ebb-and- Flood watering systems have been introduced for effective sub-irrigation and nutrient delivery within closed systems. Such a system was adapted in South Africa, to develop a vegetable production unit for use by families in rural communities, while saving substantial amounts of water. A need to further improve the WUE of this system was subsequently identified. Two studies were conducted at the experimental farm of the University of Stellenbosch (Department of Agronomy). The first trial was conducted under controlled conditions in a glasshouse, and the second under open field conditions. In the first trial, Beta vulgaris (Swiss chard) and Amaranthus spp. ('Imbuya') were grown in two root media; gravel and pumice. In addition, an 'Ebb-and-Flood' and a 'Constant level' system were used with nutrient solutions at two electrical (EC) conductivity levels 1.80 and 3.60 mS cm-I. The results of this (2x2x2x2) factorial experiment indicated that a combination of the 'Ebb-and-Flood' system with gravel as a root medium produced the best results at a low EC, when 'imbuya' was used. A high total WUE was found with 'imbuya', (7.35 g L-I) at EC 1.80 mS cmicompared to a relatively low WUE of 5. 90 g L-I when the 3.60 mS cm-I nutrient solution was used. In the second trial, 'Imbuya's' foliage dry mass, leaf area and WUE was evaluated under field conditions at the Stellenbosch University experimental farm, during the summer of2002. The experimental farm (33°55'S, 18°52'E) is situated in the cooler coastal wine grape-producing region of South Africa with a relatively high annual winter rainfall. This trial was conducted on an alluvial soil, with clay content of 25% and a pH of 5.9 (KC!). A closed 'Ebb-and-Flood' system was compared with two open field irrigation systems ('Drip' and 'Flood') using nutrient solutions at two electrical conductivity levels (1.80 and 3.60 mS cm-i) in all three cases. Foliage dry mass, leaf area as well as WUE was best with 'Drip' irrigation, when a nutrient solution with an electrical conductivity of 3.60 mS cm-i was used. In spite of the fact that additional ground water was available for the soil grown 'Drip' and 'Flood' treatments, the 'Ebb-and-Flood' system outperformed the 'Flood' treatment, especially when the nutrient solution with an EC of 3.6 mS cm-i was used. Insufficient root aeration in the flooded soil could have been a contributing factor. The fact that the 'Ebb-and-Flood' and 'Drip' systems gave the best results when the high EC solution was used to fertigate the plants, may indicate that the plants could have hardened due to the mild EC stress, better preparing them to adapt to the extreme heat that was experienced in the field.
AFRIKAANSE OPSOMMING: Swak: bestuur van water en 'n swak: water-gebruik-doeltreffendheid (WOD) is as een van die belangrikste probleme geïdentifiseer wat deur groente produsente in die meeste ontwikkelende lande, insluitend Suid-Afrika, ervaar word. Hierdie swak bestuur en benutting van water het daartoe bygedra dat 'n drastiese afname in die kwaliteit asook in die kwantiteit van beskikbare water ervaar word. In Suid-Afrika gebruik die landbou-sektor ongeveer 50% van die beskikbare water. Toenemende water behoeftes vir huisgebruik, industrieë en die mynbou mag hierdie 50% aandeel van die landbou sektor laat krimp. Beter benutting van hierdie skaars hulpbron is dus noodsaaklik. Die keuse van goeie besproeiingsisteme mag waterverliese merkbaar beperk aangesien sekere sisteme se water-besparingspotensiaal beter as ander is. Aangesien besproeiingstelsels die WOD van gewasse beïnvloed, is spesiale sorg nodig waar 'n besproeiingstelsel onder hierdie toestande van beperkte waterbronne gekies moet word. 'Ebb-en-Vloed' sisteme kan aangewend word om water en voedingselemente van onder in 'n wortelmedium te laat opstoot en in 'n geslote sisteem te laat terugdreineer. So 'n sisteem is in Suid-Afrika ontwikkel waarmee groente vir families in landelike gebiede geproduseer kan word terwyl water bespaar word. 'n Behoefte om die WOD van hierdie produksiesisteem verder te verbeter is egter geïdentifiseer. Twee ondersoeke is by die Universiteit van Stellenbosch se proefplaas (Departement Agronomie) gedoen. Die eerste proef is onder beheerde omgewingstoestande in 'n glashuis uitgevoer en die tweede onder veld toestande. In die eerste proef is Beta vulgaris (Snybeet) en Amaranthus spp. ('Imbuya') in twee tipes wortelmedia; gruis en puimsteen verbou. 'n 'Ebb-en-Vloed' asoook 'n 'Konstante vlak' besproeiingsisteem is gebruik terwyl voedingsoplossings ook by twee peile van elektriese geleiding (EC) teen 1.80 en 3.60 mS cm-I toegedien is. Die resultate van hierdie (2x2x2x2) fakroriaal eksperiment het aangetoon dat 'n kombinasie van die 'Ebb-en-Vloed' sisteem met gruis as 'n wortelmedium die beste resultate teen 'n lae EC lewer waar 'imbuya' gebruik is. Die WOD met 'imbuya' was hoog (7.35 g L-1) by 'n EC van 1.80 mS cm-I, vergeleke met 'n relatief lae WOD van 5. 90 g L-1 waar die 3.60 mS cm-I voedingsoplossing gebruik is. In die tweede proef is 'Imbuya' se droë blaarmassa, blaar oppervlakte en WOD onder veldtoestande op die Universiteit van Stellenbsoch se proefplaas in die somer van 2002 ge-evalueer. Die proefplaas (33°55'S, 18°52'E) is in die koeler kusstreke van die wyndruif produksiegebied in die winterreëngebied van Suid-Afrika geleë. Hierdie proef is op alluviale grond met 25% klei en 'n pH van 5.9 (KCi) uitgevoer. 'n Geslote 'Ebb-en-Vloed' sisteem is met twee veld-besproeiingsisteme vergelyk ('Drup' en 'Vloed') terwyl voedingsoplossings teen twee peile van elektriese geleiding (1.80 en 3.60 mS cm-I) in al drie gevalle gebruik is. Blaar droëmassa, blaaroppervlakte asook die WGD was die beste met 'Drup' besproeiing waar die EC van die voedingsoplossing 3.60 mS cm-I was. Ten spyte van die feit dat ekstra grondwater vir die 'Drup' and 'Vloed' behandelings beskikbaar was, het die 'Ebben- Vloed' stelsel beter as die 'Vloed' behandeling gedoen veral waar die voedingsoplossing se EC 3.6 mS cm-I was. Swak wortelbelugting was waarskynlik die rede waarom vloedbesproeiing swak produksie gelewer het. Die feit dat die 'Drup' en die 'Ebb-en-Vloed' behandelings in die veldproef die beste gedoen het waar die EC hoog was, mag moontlik met die gehardheid van die plante verband hou wat aan ekstreem warm en dor toestande blootgestel was.
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Jones, Cullen Brandon. "Groundwater-Surface Water Interactions near Mosier, Oregon". PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/3414.
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The town of Mosier, Oregon, is located near the east, dry end of the Columbia River Gorge, and the local area is known for cherry orchards that rely heavily on groundwater for irrigation. The CRBG groundwater system in Mosier has experienced groundwater declines of up to 60 meters due to over-pumping and or commingling. Declining groundwater levels have led to concerns over the sustainability of the resource, as it is the principle water source for irrigation and domestic use. Despite numerous previous studies of groundwater flow in CRBG aquifers here and elsewhere in the Columbia River basin, an aspect that has received relatively little attention is the interaction between groundwater and surface waters at locations where interflow zones are intersected by the surface waters.
The objective of my research is to investigate how CRBG interflow zone exposures in Mosier Creek may be controlling groundwater elevations in the area. The methods used include: (1) geochemical analysis of well cuttings and detailed geologic mapping along area streams to identify interflow zones of individual CRBG flows, (2) analysis of stream discharge data and groundwater elevation data to confirm exchange of groundwater and surface waters, and (3) collection and analyses of 31 water samples from area wells, streams, and springs, to determine if waters from individual CRBG aquifers can be hydrochemically identified and to further constrain understanding of surface and groundwater interactions.
My study confirms that the general elevation of the Pomona Member and Basalt of Lolo interflow zone creek exposure is coincident with the elevation where a change in slope of the decline trend in 2004 is seen in Mosier area well hydrographs. Furthermore, the results of stream discharge data indicated a close connection between drawdown from groundwater pumping during irrigation season and groundwater- surface water interaction. At the time of drawdown in the upper-most CRBG aquifer (Pomona), the stream transitions from gaining to losing water into the groundwater system.
Elemental chemistry data indicates the Frenchman Springs Sentinel Gap aquifer waters are the most evolved waters in this study. Stable isotopic data reinforced this determination as the Sentinel Gap waters are the lightest, or most negative, with regard to δD and δ18O. Sentinel Gap samples were more depleted than other aquifer samples by 4.38 to 6.89 0/100 for δD and 0.39 to 0.59 0/100 for δ18O. The results of the general chemistry and isotope data reveal a more evolved chemical signature in lower watershed groundwater versus a less evolved signature for waters from wells located higher up on the Columbia Hills anticline. This was interpreted to be the result of the major structural features in the area providing for a more regional pathway of recharge in lower watershed groundwaters, versus a more local source of recharge for upper watershed groundwaters. There was also a pronounced commingled signature in the elemental ratios of lower watershed aquifer waters. The suspected mechanism of recharge to lower watershed wells is through younger Cascadian deposits upslope from the local watershed.
The findings of this study reveal the importance of a detailed understanding of CRBG stratigraphy and its relation to surface waters, especially for other areas within the Yakima Fold Belt or Oregon and Washington. Studies that do not consider the influence that individual CRBG flows can have on groundwater-surface water interactions, and the groundwater system as a whole, run the risk of improperly assessing the groundwater resource for a region.
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Shukri, Ibrahim M. "Municipal water use: an Oregon case study". PDXScholar, 1985. https://pdxscholar.library.pdx.edu/open_access_etds/523.
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There are two approaches to estimating the quantity of water required in an urban area: the requirements approach and the economic approach. The requirements approach extrapolates from past growth trends of the urban area. Water consumption and population are extrapolated into the future using a trend line based on prior years; the future requirements of the area are determined according to past experience. This approach served well when water was essentially a free good. But now that it is an economic good that requires production, the requirements approach tends to overestimate water requirements. The alternative is the economic approach which takes into account different characteristics of an urban area. Among these characteristics are economic, demographic, geographic and climatic. This approach leads to better use of information to estimate future water consumption. This dissertation is a cross-sectional analysis of municipal water districts in Oregon. It is based on the economic approach. Data on specified variables were collected by sampling and surveying more than 1,000 water districts in Oregon. The data were analyzed using Multiple Linear Regression. The general hypothesis of the study is that municipal water use in Oregon can be estimated by using independent variables other than size. Weather, per capita income, average price of water, marginal cost of water, the amount of fixed charge for basic water use, allowed quantity of basic water use, and non-residential connections were regressed on the per capita per day water consumption for residential, commercial, industrial and total users. The hypothesis was confirmed; price was a significant variable in the different uses of water. Climate was found to be significant in estimating the residential use. Variable charge as well as climate were found to be significant in commercial use. Fixed charge and sewage charge were somewhat significant in estimating the industrial use. The results of the study are consistent with the theory and the findings of previous studies. Three models were developed; a general model, a residential model and a non-residential model. These models helped to identify climate and price as effective variables in estimating water demand in the study area within the context of the economic approach.
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Al-Amoud, Ahmed Ibrahim. "A water management model for trickle irrigated row crops". Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292233.
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Naab, Jesse Bonaventure. "Interaction of canopy and root system in water use of potato". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308564.
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Manamathela, Sibongile Amelia. "The water footprint of selected crops within the Olifants/Doorn Catchment, South Africa". University of the Western Cape, 2014. http://hdl.handle.net/11394/4751.
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>Magister Scientiae - MScRapidly increasing global population is adding more pressure to the agricultural sector to produce more food to meet growing demands. However the sector is already faced with a challenge to reduce freshwater utilisation as this sector is currently using approximately 70% of global water freshwater resources. In South Africa, the agriculture sector utilizes approximately 62% of freshwater resources and contributes directly about5% to the Gross Domestic Product. South Africa is a water scarce country receiving less than 500mm/year of precipitation in most parts of the country, and consequently approximately 90% of the crops are grown under irrigation. Studies have evaluated irrigation practices and crop water use in the country. However information is lacking on the full impact of South African horticultural products on freshwater resources. The water footprint concept can be used to indicate the total and source (blue/green) of water used to produce the crops. Information about water footprint (WF) can be used for identifying opportunities to reduce the water consumption associated with production of vegetables and fruits at the field to farm- gate levels, including the more effective use of rainfall (green water) as opposed to water abstracted from rivers and groundwater (Blue water). It can also be used to understand water related risks associated with the production of crops and facilitate water allocation and management at catchment/water management scale. While the potential value of water footprint information is well recognized there is still inadequate knowledge on how best to determine the water footprints of various crops within a local context. The aim of this study was to determine the water footprint and the crop water productivity of navel oranges, pink lady apples and potatoes produced with the Olifant/Doorn water management area in South Africa.The water footprint of the navel oranges, pink lady apples and potatoes assessed following the water footprint network method was 125 litres/ kg, 108 litres/kg and 65 litres/ kg respectively. The study concluded that water footprint studies should be carried out on the whole catchment instead of one farm in order to assess the sustainability of the process.
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Valdez, Aguilar Luis Alonso. "Effect of alkalinity in irrigation water on selected greenhouse crops". Texas A&M University, 2004. http://hdl.handle.net/1969.1/2773.
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Effect of Alkalinity in Irrigation Water on Selected Greenhouse Crops. (August 2004)
Luis Alonso Valdez Aguilar, B.S., Universidad Aut??noma de Nuevo Le??n, Mexico;
M.S., Universidad Aut??noma Chapingo, Mexico
Chair of Advisory Committee: Dr. David Wm. Reed
Bicarbonate (HCO3-) and carbonate (CO32-) are the most important ions that determine alkalinity. When the carbonates accumulate in a growing medium, the growing medium solution pH reaches levels that cause plant growth inhibition, which is caused primarily by the transformation of soluble forms of Fe into insoluble forms.
The general objective of this research was to provide information about the limits of tolerance to alkalinity in ornamental plants, and to study the interaction of ions such as ammonium (NH4+) and nitrate (NO3-) on the response of plants to alkalinity, as well as the effect of the counter-ions potassium (K+), sodium (Na+), cesium (Cs+), ammonium (NH4+) and rubidium (Rb+).
The maximum SPAD index was estimated to occur at 0 mM of NaHCO3 in chrysanthemum, mini-rose, and hibiscus ??Bimini Breeze?? and ??Mango Breeze??. For vinca it was set at 2.64 mM. A 15% decrease from the maximum SPAD index was considered the threshold to declare the toxic concentration of NaHCO3, which was calculated based on the maximum SPAD index predicted by the models.
The toxic concentration of NaHCO3 was set at 4.1, 1.1, 6.7, 3.1, and 6.3 mM of NaHCO3 in chrysanthemum, mini-rose, vinca, and hibiscus ??Mango Breeze?? and ??Bimini Breeze??, respectively. Hibiscus ??Bimini Breeze?? was considered tolerant to alkalinity, due to increased Fe-reduction capacity and acidification of the growing medium.
In the hydroponic experiment, results showed that the NH4+:NO3- ratio altered the response of sunflower plants to alkalinity. Sunflower plants grew better in solutions containing 5 mM NaHCO3 prepared with a 0.25:0.75 NH4+:NO3- ratio. This was possible due to the reaction of NH4+ with the HCO3-, which reduced its buffering capacity.
The response to HCO3--induced alkalinity was modified by the counter-cation of HCO3-. In bean plants, at low-to-intermediate levels of Na+ and HCO3- induced approximately same growth decrease. At high concentration, Na+ induced a decrease on shoot growth that exceeded the toxic effects of HCO3-. Thus, the toxic effect of Na+ is higher than that of HCO3- when its concentration is high. Rubidium was extremely toxic at concentrations of 7.5 mM.
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Mhlauli, Ntuthuzelo Columbus. "Growth analysis and soil water balance of selected vegetable crops". Diss., University of Pretoria, 2000. http://hdl.handle.net/2263/26200.
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Please read the abstract in the section 00front of this documentDissertation (M Inst Agrar (Horticulture Science))--University of Pretoria, 2000.
Plant Production and Soil Science
unrestricted
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Juza, Holly Kay. "Water Quality Model for South Slough, Coos Bay, Oregon". PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/5046.
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The South Slough Estuary is located off Coos Bay along the southern coast of Oregon. It is divided into two channels that meet and continue to Coos Bay at the Charleston Harbor. There are six major contributing streams to South Slough. After rainfall events, the level of coliform bacteria in the slough increases because of stream bacteria loading. This is due to cattle grazing in the drainage areas, failed septic systems from private homes, and sewage sludge applied to the County landfill, which drains into the slough. The Oregon Health Division has enforced a Sanitation Management Plan for Commercial Shellfish Harvesting in South Slough that specifies closure of commercial shellfish harvesting for certain rainfall and flood events. The purpose of this study is to analyze and improve the current understanding of the hydraulics and water quality of the South Slough Estuary. This was achieved by calibrating the South Slough using the water quality model CEQUAL- W2. It was calibrated for the following parameters water surface elevations, velocity, temperature and total dissolved solids. A management analysis was also done analyzing the transport of bacteria and a conservative tracer. Model predictions for water surface elevations at one of the monitoring sites, Hinch Road Bridge, was significantly lower than measured elevations. There was an excellent correlation of velocity, and reasonable timing of peaks due to tidal effects. Model predictions for temperature and total dissolved solids match measured values well. To improve the accuracy of the model the following was recommended; install a raingage in the South Slough, measure temperature and constituent concentrations at inflow locations, survey the S4 current meter, new soundings performed of the Winchester Creek arm and at the Hinch Road Bridge gaging station, and investigate the possibility of an obstruction near the Hinch Road Bridge gaging station.
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Mentz, Wilma Henriette. "Tolerance of selected crops to gypsiferous water originating in coal mines". Thesis, Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-11112003-155702.
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Fant, Chas. "CliCrop: A one-dimensional model to calculate water stress on crops". Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1460854.
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Litllefield, Joanne y Susan McGinley. "Managing Water and Nutrients in Vegetable Crops: Evaluation Tools for Growers". College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2002. http://hdl.handle.net/10150/622243.
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Evers, Byron J. "Growing crops for biofuel and forage while conserving soil and water". Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14140.
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Master of ScienceDepartment of Agronomy
Humberto Blanco
The use of renewable feedstocks to produce cellulosic ethanol is quickly becoming a reality as facilities to produce cellulosic ethanol are scheduled to open in the upcoming years. Initial feedstocks for these facilities are thought to be crop residues such as corn (Zea mays L.) and wheat (Triticum aestivum L.) residues. However, additional feedstocks, such as perennial warm-season grasses (WSG), maybe needed to meet the demands of these bioenergy facilities. Thus, the development of regional dedicated energy crop systems is a high priority. Our objectives were to: a) assess the impacts of growing WSG on water storage, soil physical and hydraulic properties, soil organic carbon (SOC) dynamics, and water and wind erosion as compared with row crops, b) assess the impacts of growing WSG on biomass and forage production and quality and c) determine the most adaptable WSG species to dryland conditions. A number of dedicated energy crops and their performance across three different moisture regimes in Kansas were studied. Biomass yield, soil physical and hydraulic properties, and soil water and wind erosion parameters were measured between August 2010 and August 2012. Additionally, forage quality under two cutting systems (biofuel and forage) and two harvest heights (0.1 m and 0.2 m) and water infiltration was determined in 2011. Differences in bulk density, water retention, infiltration and SOC were found to be minimal. However, differences in wind and water erosion parameters indicate that WSG can protect soil from erosion. Furthermore, soil water data indicate that WSG are better suited to use early season moisture to accumulate biomass than annual row crops. Yield results indicate that a two cut hay system with a 0.1 m cutting height can produce more biomass compared with a one cut biofuel system. Additionally, the hay system improved forage quality parameters. Data collected from this project provided insights into the viability of growing various dedicated energy crops across the region during the first five years of production.
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Jones, Randall Alan. "Classifying Oregon lake-watershed ecosystems for regional water resources assessment". PDXScholar, 1987. https://pdxscholar.library.pdx.edu/open_access_etds/3712.
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Natural lake-watershed ecosystems in Oregon compose a diverse and valuable assemblage of land and water resources. With an increasing demand on lakes for recreation, water supplies, and aesthetic values and an increase in available data on Oregon lake systems, there is a need for applicable and timely scientific water management information about lake conditions statewide. This thesis is an attempt to summarize some of the data collected on natural Oregon lake-watershed ecosystems.
The purpose of the thesis is to identify the most typical natural systems out of an initial data base of twenty-four variables, measured over ninety-eight lake-watershed ecosystems. The selected variables are reduced to five common factors using principal components factor analysis. K-means cluster analysis is used to create similar groups of lake systems. These groups are compared to ecoregions in Oregon and a typical, representative lake ecosystem is identified for each group. Results show that several lake systems of the state are unique.
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Psaris, Alexander Michael. "Assessing Hydrologic and Water Quality Sensitivities to Precipitation Changes, Urban Growth and Land Management Using SWAT". PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1783.
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Precipitation changes and urban growth are two factors altering the state of water quality. Changes in precipitation will alter the amount and timing of flows, and the corresponding sediment and nutrient dynamics. Meanwhile, densification associated with urban growth will create more impervious surfaces which will alter sediment and nutrient loadings. Land and water managers often rely on models to develop possible future scenarios and devise management responses to these projected changes. We use the Soil and Water Assessment Tool (SWAT) to assess the sensitivities of stream flow, sediment, and nutrient loads in two urbanizing watersheds in Northwest Oregon, USA to various climate and urbanization scenarios. We evaluate the spatial patterns climate change and urban growth will have on water, sediment and nutrient yields. We also identify critical source areas (CSAs) and investigate how implementation of vegetative filter strips (VFS) could ameliorate the effects of these changes. Our findings suggest that: 1) Water yield is tightly coupled to precipitation. 2) Large increases in winter and spring precipitation provide enough sub-surface storage to increase summertime water yields despite a moderate decrease in summer precipitation. 3) Expansion of urban areas increases surface runoff and has mixed effects on sediment and nutrients. 4) Implementation of VFS reduces pollutant loads helping overall watershed health. This research demonstrates the usefulness of SWAT in facilitating informed land and water management decisions.
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Hall, Nicola. "Stable isotopes, molecular markers and water use in Brassicas". Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324874.
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Breyer, Elizabeth Yancey. "Household Water Demand and Land Use Context: A Multilevel Approach". PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/1670.
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Urban water use arises from a mix of scale-dependent biophysical and socioeconomic factors. In Portland, Oregon, single-family residential water use exhibits a tightly coupled relationship with summertime weather, although this relationship varies with land use patterns across households and neighborhoods. This thesis developed a multilevel regression model to evaluate the relative importance of weather variability, parcel land use characteristics, and neighborhood geographic context in explaining single-family residential water demand patterns in the Portland metropolitan area. The model drew on a high-resolution panel dataset of weekly mean summer water use over five years (2001-2005) for a sample of 460 single-family households spanning an urban-to-suburban gradient. Water use was found to be most elastic with respect to parcel-scale building size. Building age was negatively related to water use at both the parcel and neighborhood scale. Half the variation in water use can be attributed to between-household factors. Between-neighborhood variation exerted a modest but statistically significant effect. The analysis decomposed household temperature sensitivity into four components: a fixed effect common to all households, a household-specific deviation from the fixed effect, a separate extreme heat effect, and a land use effect, where lot size exaggerated the effect of temperature on water use. Results suggested that land use planning may be an effective non-price mechanism for long-range management of peak demand, as land use decisions have water use implications. The combined effects of population growth, urbanization, and climate change expose water providers to risk of water stress. Modeling fine-grain relationships among heat, land use, and water use across scales plays a role in long-range climate change planning and adaptation.
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Dagget, Steven Gregory. "Evidence for the Eutrophication of Selected Coastal Dunal Lakes: Historical Comparison of Indices for Nutrient Enrichment". PDXScholar, 1994. https://pdxscholar.library.pdx.edu/open_access_etds/4723.
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Three coastal Oregon dunal lakes, Mercer Lake, Munsel Lake, and Woahink Lake, were studied in an effort to determine if eutrophication has occurred since initial studies were conducted in 1938 and to determine each lake's current trophic status. Data collected in 1991 and 1992 for phytoplankton primary productivity; chlorophyll gi phytoplankton species, biovolumes, and densities; nutrients; optical characteristics; and dissolved oxygen were compared with historical data sets. Additional data for zooplankton, benthic invertebrates, and other relevant limnological data were used to more completely characterize each lake. Phytoplankton primary productivity measurements indicate that biological productivity has increased at each lake since 1969-1971. Chlorophyll ~ concentrations appear to have increased only at Mercer Lake. Other limnological data are insufficient to determine if and to what extent these lakes have eutrophicated. Based on data collected in 1991 and 1992, the current trophic state of each lake can be described as follows: Mercer Lake is mesotrophic to eutrophic but closer to mesotrophic, Munsel Lake is oligotrophic to mesotrophic but closer to mesotrophic, and Woahink Lake is oligotrophic to mesotrophic but closer to oligotrophic.
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Harris, P. M. "Tempering the effects of water stress in sugar beet and potato crops". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385139.
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Hoskins, Tyler Courtney. "Water and nutrient transport dynamics during the irrigation of containerized nursery crops". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/48165.
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Increased water- and fertilizer-use-efficiency in containerized crop production, via reduced water loss, enhances crop-available nutrients while reducing non-point source agrichemical contributions in accordance with regulatory standards. Previous studies detailed nutrient leaching patterns throughout crop production seasons, leaving little known about water and dissolved nutrient (solute) movement through soilless substrates during irrigation. The following experiments evaluated fundamental water and solute transport principles through pine-bark based substrates. 1) Ilex crenata Thunb. 'Bennett's Compactum' were grown in 2.7 L containers. Tensiometers detected wetting front (WF) movement throughout the substrate during irrigation. 2) Tracer solution (containing NO3-, PO43- and K+) and deionized water (DI) were applied to substrate-filled columns to characterize tracer breakthrough under saturated and unsaturated conditions. 3) Controlled-release fertilizer (CRF) was topdressed (surface-applied), incorporated (throughout substrate), dibbled (center of substrate) or not applied to fallow substrate, irrigated with DI and leachate analyzed to determine nutrient concentrations throughout irrigation. Tensiometers revealed that seasonal root growth affected substrate pre-irrigation moisture distribution. Wetting fronts channeled through the substrate before becoming thoroughly wetted. Tracer breakthrough occurred with less effluent volume under unsaturated conditions. Breakthrough of NO3- and PO43- was relatively conservative, though 37% of K+ was retained by the substrate. Leachate concentrations for topdressed and incorporated CRF peaked early (first 50mL effluent) before diminishing with continued leaching. Leachate concentrations for dibbled CRF initially increased (first 150mL leachate), plateaued and then diminished. These results show the relative rapidity which water and solutes move through pine-bark during irrigation and demonstrate methods for future research on within-irrigation solute transport.Master of Science
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Pettus, Paul Bryce. "Modeling Fecal Bacteria in Oregon Coastal Streams Using Spatially Explicit Watershed Characteristics". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1493.
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Pathogens, such as Escherichia coli and fecal coliforms, are causing the majority of water quality impairments in U.S., making up ~87% of this grouping's violations. Predicting and characterizing source, transport processes, and microbial survival rates is extremely challenging, due to the dynamic nature of each of these components. This research built upon current analytical methods that are used as exploratory tools to predict pathogen indicator counts across regional scales. Using a series of non-parametric methodologies, with spatially explicit predictors, 6657 samples from non-estuarine lotic streams were analyzed to make generalized predictions of regional water quality. 532 frequently sampled sites in the Oregon Coast Range Ecoregion, were parsed down to 93 pathogen sampling sites in effect to control for spatial and temporal biases. This generalized model was able to provide credible results in assessing regional water quality, using spatial techniques, and applying them to infrequently or unmonitored catchments. This model's 56.5% explanation of variation, was comparable to other researchers' regional assessments. This research confirmed linkages to land uses related to anthropogenic activities such as animal operations and agriculture, and general riparian conditions.
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Kotsopulos, Spiridon I. "On the evaluation of risk of failure in irrigation water delivery". Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236328.
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Kumar, Ashok. "The effect of drought on the water relations and growth of two Brassica species". Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254669.
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Cole, Jason. "Use of water potential measurements for assessing water stress in Vitis vinifera L. cv. Tempranillo grown in Southern Oregon". Master's thesis, ISA/UL, 2012. http://hdl.handle.net/10400.5/8598.
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Mestrado Vinifera EuroMaster - Instituto Superior de AgronomiaA study was conducted to investigate the practical use of four methods for measuring plant water potential (!) of Vitis vinifera L. cv. Tempranillo (syn. Tinta Roriz, Aragónez) under field conditions within the Southern Oregon American Viticultural Area. Predawn leaf water potential (!pd), midday leaf water potential (!l-md), midday stem water potential (!s-md) and early morning stem water potential measured between 07:00h and 08:00h solar time (!s-em) were each measured on vines before and after the initiation of irrigation. Measurements were conducted on the same vines and on the same dates both before and after veraison. Irrigation was applied based on an estimation of vineyard evapotranspiration (ETc) and consisted of four treatments: 70% of ETc continuously (70-70), 35% of ETc continuously (35-35), 70% ETc before veraison and 35% ETc after veraison (70-35) and 35% before veraison and 75% ETc after veraison (35- 70). Irrigation was initiated based on !l-md. When assessing vineyard variability before the initiation of irrigation, with !pd ranging between -0.05 and -0.53, all four measurement types were able to distinguish between high vigor (HV) and low vigor (LV) zones and able to categorize vines under previously established thresholds. However, !l-md showed a tendency to underestimate vine water status at levels greater than -0.9 Mpa. When comparing !s-em, !s-md and !l-md, early morning measurements showed significant differences between irrigation treatments on 3 of 4 measurement dates while midday measurements were able to distinguish significant differences on only 1 of 4 dates. !s-em measurements were generally able to distinguish differences between vine water status even when morning cloud cover was present. Linear regression analysis of !pd versus !s-em, !s-md and !l-md at one site resulted in significant r2 values of 0.62, 0.69 and 0.58, respectively. Linear regression analysis of !s-md versus !l-md using data from both sites resulted in r2 values of 0.88. Overall, !s-em seemed to provide a better option for differentiating plant water status of Tempranillo grapevines in Southern Oregon compared to !s-md and !l-md within the range of water deficit levels studied here. !s-em was able to show differences between the water status of vines before the initiation of irrigation as well as differentiate between irrigation treatments later in the year. However, questions remain about the environmental and physiological factors that might impact the results of this method before water deficit threshold levels can be clearly defined
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Osman, Mohammed A. "Effect of water stress on the physiology, growth, and morphology of three pearl millet genotypes". Diss., The University of Arizona, 1988. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1988_11_sip1_w.pdf&type=application/pdf.
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Fields, Jeb Stuart. "Soilless Substrate Hydrology and Subsequent Impacts on Plant-Water Relations of Containerized Crops". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/74925.
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Freshwater is a finite resource that is rapidly becoming more scrutinized in agricultural consumption. Specialty crop producers, especially ornamental crop producers, must continually improve production sustainability, with regards to water resource management, in order to continue to stay economically viable. Soilless substrates were initially developed to have increased porosity and relatively low water holding capacity to ensure container crops would not remain overhydrated after irrigations or rain events. As a result, substrates were selected that are now considered to be in efficient in regards to water resource management. Therefore, to provide growers with additional means to improve production sustainability, soilless substrate hydrology needs be innovated to provide increased water availability while continuing to provide ample air filled porosity to ensure productive and efficient water interactions. Historically, soilless substrates have been characterized using "static" physical properties (i.e. maximum water holding capacity and minimum air-filled porosity). The research herein involves integrating dynamic soilless substrate hydraulic properties to understand how substrate hydrology can be manipulated to design sustainable substrates. This task involved adapting new technologies to analyze hydrological properties of peat and pine bark substrates by employing evaporative moisture characteristic measurements, which were originally designed for mineral soils, for soilless substrate analyses. Utilizing these evaporative measurements provide more accurate measures of substrate water potentials between -10 and -800 hPa than traditional pressure plate measurements. Soilless substrates were engineered, utilizing only three common substrate components [stabilized pine bark (Pinus taedea L.), Sphagnum peatmoss, and coconut coir fiber], via particle fractionation and fibrous additions. The engineering process yielded substrates with increased unsaturated hydraulic conductivity, pore connectivity, and more uniform pore size distributions. These substrates were tested in a greenhouse with irrigation systems designed to hold substrates at (-100 to -300 hPa) or approaching (-50 to -100 hPa) water potentials associated with drought stress. Substrate-water dynamics were monitored, as were plant morphology and drought stress indicators. It was determined that increased substrate unsaturated hydraulic conductivity within the production water potentials, allowed for increased crop growth, reduction in drought stress indicators, while producing marketable plants. Furthermore, individual plants were produced using as low as 5.3 L per plant. Increased production range substrate hydraulic conductivity was able to maintain necessary levels of air-filled porosity due to reduced irrigation volumes, while providing water for plants when needed. The substrates were able to conduct water from throughout the container volume to the plant roots for uptake when roots reduced substrate water potential. Furthermore, increased substrate hydraulic conductivity allowed plants within the substrate to continue absorbing water at much lower water potentials than those in unaltered (control) pine bark. Finally, HYDRUS models were utilized to simulate water flux through containerized substrates. These models allowed for better understanding of how individual hydraulic properties influence substrate water flux, and provided insight towards proportions of inaccessible pores, which do not maintain sufficient levels of available water. With the models, researchers will be able to simulate new substrates, and utilize model predictions to provide insight toward new substrates prior to implementing production tests. It has been determined, that increasing substrate hydraulic conductivity, which can be done with just commonly used components, water requirements for production can be reduced, to produce crops with minimal wasted water resources. Concluding, that re-engineering substrate hydrology can ameliorate production sustainability and decrease environmental impact.Ph. D.
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Neagley, John P. O'Brien Robert T. "Market allocation of agricultural water resources in the Salinas River Valley". Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA245767.
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Thesis (M.S. in Management)--Naval Postgraduate School, December 1990.Thesis Advisor(s): Moore, Thomas P. Second Reader: Gates, William R. "December 1990." Description based on title screen as viewed on April 2, 2010. DTIC Identifier(s): Water Supplies, Irrigation Systems, Salinas River Valley (California), Theses, Free Market, Water Conservation, Public Policy, Salt Water, Policies, Farm Crops, Marketing. Author(s) subject terms: Groundwater Allocation, Groundwater Markets, Agricultural Groundwater, Salinas River Valley. Includes bibliographical references (p. 90-94). Also available in print.
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Frankel, Deborah Jean. "The effects of coypu Myocaster coypus (nutria) trapping on the water quality of South Johnson Creek, Beaverton, Oregon". PDXScholar, 2007. https://pdxscholar.library.pdx.edu/open_access_etds/4280.
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Nutria are semi-aquatic rodents, non-native to Oregon. They are an invasive species that damage stream banks with burrowing and cause destruction of native vegetation; activity that may cause deterioration of stream water quality. I hypothesized that my study's duration and pattern of nutria trapping along South Johnson Creek would be sufficient to lead to a significant change in turbidity, dissolved oxygen (DO), total dissolved solids (TDS), total solids (TS), and total suspended solids (TSS).
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Onyango, J. C. "Some effects of water deficit on rainfed landraces of rice (Oryza sativa L.) indigenous to Kenya". Thesis, University of Sussex, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304869.
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Monteil, Oscar Vazquez. "Wastewater irrigation of crops : the influence of nitrogen on soil-plant interactions". Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303449.
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Schock, Kevin A. "Predicting Seepage of Leachate from the St. Johns Landfill to Ground and Surface Water Systems". PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4648.
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Determination of the vertical and horizontal groundwater hydraulic gradient within a landfill is the first step in determining the potential of groundwater contamination from the landfill leachate. The length of a study and the frequency at which measurements are recorded can greatly affect the description of the local groundwater environment. A more comprehensive analysis can be preformed for longer periods of study and greater measurement frequency. The intent of this study was to install a continuous groundwater level monitoring system around the st. Johns Landfill for a minimum study length of one year. This would allow a more thorough study of the seasonal character and behavior of the groundwater system beneath the landfill than in previous studies. Particular interest was paid to groundwater level changes resulting from seasonal weather changes. Additional attention was paid to other forcing mechanisms which could be perturbing groundwater levels, and variations in the geochemical groundwater constituents. Included throughout this report is a literature review of various studies pertinent to the analysis of groundwater level variations. Seasonal variations in vertical groundwater hydraulic gradients were reviewed and time averaged vertical seepage rates were estimated. Areal plots of groundwater levels were used to view expected horizontal groundwater hydraulic gradients during seasonal maximum and minimum groundwater levels. A computer model was developed to study the effects temporal variations in slough water levels had on groundwater seepage rates through the perimeter dike separating the landfill from the sloughs. The modeling provided an estimate of the average horizontal leachate seepage rate into the sloughs. Comparison plots of monitoring well groundwater levels were used to analyze potential swash zones beneath the landfill and potential effects of lowered water levels in Bybee Lake. Spectral analysis techniques were imployed to determine the dominant frequencies observed in the groundwater levels, allowing determination of the type of forcing mechanism driving the fluctuations. Geochemical groundwater constituents were statistically analyzed to determine the significance of observed trends in the data: areal plots of chloride concentrations and electrical conductivity were made to view constituent distributions within the underlying aquifers. Estimated vertical and horizontal groundwater seepage rates into the local waters showed that horizontal leachate seepage is insignificant compared to vertical leachate seepage. Groundwater level comparison plots indicated no significant swashing beneath the landfill occurred. The statistical studies on groundwater forcing mechanisms indicated that either the slough or the Columbia River water levels could be perturbing groundwater levels. Trend analyses on the geochemical groundwater constituents indicated significant, positive trends in chloride concentrations, and undeterminable trends in electrical conductivity.
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Bonnette, Matthew Ryan Lee. "The Effects of Scale Variation on Single-Family Residential Water Use in Portland, OR". PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3505.
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With growing urban populations and increasing concerns over the effects of climate change on water supplies, there has recently been a significant amount of interdisciplinary research focused on identifying the drivers of urban water use. Due to unavailability of individual or household level data, these studies are often limited to using spatially aggregated data. There is concern that this aggregation of data may be leading to misrepresentations of the drivers of urban water use, yet there have been few studies that have addressed this concern. As in all spatial quantitative analyses, studies in this area should consider how the spatial scales chosen for analysis are affecting the results. The purpose of this research is to use a case study of single-family residential (SFR) water use in Portland, Oregon to determine the extent to which scale variation significantly affects the patterns of SFR water use, and whether household scale water use is influenced by neighborhood and census tract characteristics. The results of this analysis provide evidence that aggregating household scale water use data can mask meaningful patterns in SFR water use and potentially provide misleading information on what is influencing water use habits. This research also shows that using the chosen exploratory variables, there is a statistically significant, but not substantial, cross-scale influence on household scale water use by neighborhood and census tract characteristics.
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House-Peters, Lily. "Examining the Effects of Climate Change and Urban Development on Water Demand: A Multi-Scale Analysis of Future Water Demand in Hillsboro, Oregon". PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/2251.
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In the Portland, Oregon, metropolitan area, suburban cities such as Hillsboro are projected to grow as people seek affordable housing near a rapidly growing metropolis. This thesis examines the combined impact of'c1imate change and urban development on both neighborhood and municipal scale residential water demand in Hillsboro, Oregon. I use two models, a surface energy balance model, Local-scale Urban Meteorological Parameterization Scheme (LUMPS), and a system dynamics model, CCDomestic, to investigate changes in residential water demand in the 2040s at two distinct spatial scales, the neighborhood and the municipality. I calibrate and validate each model to the reference period and then simulate the future (2030-2059) under three statistically downscaled global climate models and two urban development scenarios. The findings of this study indicate that climate change and urban development will not evenly affect water consumption in neighborhoods across a city. Instead, the current land cover and residential density of a neighborhood exert an important influence on the response. Heavily vegetated neighborhoods exhibit large increases in water demand under urban sprawl and warming scenarios, while neighborhoods dominated by impervious surfaces decrease water consumption under sprawl scenarios and show little change in water consumption under combined sprawl and warming scenarios. At the municipal scale findings suggest that water demand is highly sensitive to urban design and management and that the combination of urban densification and water conservation regulations could mitigate increases in water consumption from population growth and climate change.
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Dingfelder, Jacqueline. "Wicked Water Problems: Can Network Governance Deliver? Integrated Water Management Case Studies from New Zealand and Oregon, USA". PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3623.
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Integrated water management is a wicked public policy problem with no clear path to resolution. This dissertation is an in-depth qualitative comparative analysis of two collaborative governance processes created to tackle complex water problems in New Zealand and Oregon, U.S.A. Both cases convened a wide range of state and non-state actors in efforts to find common ground, build consensus for change, and develop innovative water policy solutions.
The goal of this comparative case study analysis is to gain a better understanding of collaborative network governance frameworks as applied to integrated water management and primary factors for success. The proposition posits that collaborative networks involving public, private, and non-profit actors are better equipped than government-driven efforts to develop desired outcomes. To test this proposition, the research questions probe the role of state and non-state policy actors, conditions for collaboration, strength of actor ties, development of trust and social capital, barriers to success, and the role of climate change as a policy driver in these two case studies.
The comparative case study analysis yields fascinating insights that adds to the network governance literature. In the New Zealand case, a collaborative-led process called the Land and Water Forum (LAWF) showed that this ongoing network offers benefits to creating consensus on complex water issues. LAWF succeeded in moving policy conversations forward where previous government-led efforts had failed. Within the LAWF collaborative network, non-state actors formed strong ties; however, relationships with state actors exhibited weaker ties.
With Oregon's integrated water policy, a collaborative network approach created a more conducive environment for meaningful dialogue among vested interests, and built some levels of interdependency and trust, thus generating a wider array of policy options than through previous legislative and bureaucratic efforts. However, long-standing political, legal, and institutional challenges continue to constrain effective integrated water management and the delivery of integrated outcomes in Oregon. The Oregon case did not exhibit strong leadership within the collaborative to broker challenging policy issues. Also, it faced implementation challenges as one state agency was given responsibility for stewarding integrated water management but lacked authority for implementation or coordination with other state agencies. Overcoming fragmented natural resource governance arrangements remains a daunting challenge.
This research revealed three key findings: (1) in both cases, collaborative network governance worked well for framing and designing new integrated water policies, but encountered implementation challenges; (2) managing the complexities around the intersection of top-down, vertical command and control governance with horizontal collaborative approaches remains an ongoing challenge to New Public Governance; and (3) the two cases represent examples of the use of formal and informal processes for policy development. The benefits of collaborative governance for policy development are substantial, and the limitations appear to be obstacles to overcome and not fatal flaws. The main challenge lies in transitioning from policy and planning to implementing changes on the ground affecting the way we manage water today and in the future.
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Hart, Ted David. "Root-enhanced Infiltration in Stormwater Bioretention Facilities in Portland, Oregon". PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3468.
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I evaluated the effectiveness of plant roots to increase infiltration rates within stormwater bioretention facilities (SBFs), roadside planter compartments that filter stormwater. SBFs attenuate harmful effects of stormwater by reducing peak flow and retaining pollutants, with increased infiltration that improves both these functions. Researchers have shown that roots can increase infiltration within greenhouse, lab, field, and test SBF settings. However, no researchers have yet measured either the extent to which different root characteristics can increase infiltration or the variation in root characteristics and their effect on infiltration rates among plant assemblages within currently functioning SBFs.
To determine if root-enhanced infiltration was occurring within SBFs, I hypothesized
1) there is a relationship between root characteristics and infiltration during late spring, and
2) seasonal root growth increases infiltration rates. Within Portland, OR, I measured infiltration rate from January 2014 to February 2015 and root characteristics from January-February (J-F) and May-June (M-J) 2014 in ten SBFs with "Elk Blue" rush (Juncus patens) and 1 or 2 trees of less than 8.4 cm stem diameter. During M-J, four root characteristics showed a positive relationship with infiltration rate, and two root characteristics showed a strong positive relationship with infiltration rate within the topsoil. Also, a relationship was shown between the increase (J-F to M-J 2014) in three root characteristics and the increase in infiltration rate.
To determine if root morphology and infiltration rates differed among SBFs with two different dominant vegetation taxa (small and large root biomass), I hypothesized 3) Juncus patens and tree dominant assemblage (greater root biomass) exhibits greater infiltration compared to the Carex dominant assemblage, 4) the increase in infiltration rate and root characteristics from J-F to M-J is greater in the Juncus compared to the Carex assemblage, and 5) root surface area density (RSAD) within Juncus SBFs shows a positive relationship with infiltration rate in late spring. I measured infiltration rate from January 2014 to February 2015 and root characteristics from January-February (J-F) and May-June (M-J) 2014 among five large-root (Juncus and tree) and five small-root biomass (Carex sp) SBFs. Juncus SBFs showed greater values for three root characteristics during J-F and five root characteristics during M-J 2014 compared to Carex SBFs. Also, Juncus SBFs showed an increase from J-F to M-J 2014 for five root characteristics while Carex SBFs showed no root increase. Juncus SBFs showed a relationship with four root characteristics and Carex SBFs a showed relationship with one root characteristic and infiltration rate.
This work strongly suggests plant roots increase infiltration, and thus the primary functions of SBFs. Different root characteristics appear to increase infiltration rate at different depths. Data also show larger-root biomass plants increase infiltration rate to a greater degree than smaller-root biomass plants.
I recommend considering several site and facility characteristics when determining the potential for root-enhanced infiltration. When selecting plant species to enhance infiltration, I recommend using several criteria, determining root characteristic values at certain depths, considering installation approaches, and accounting for regional climate changes.
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Ping, Zhang. "The partitioning of water loss between crop transpiration and soil evaporation in potato crops". Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303926.
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Björnberg, Emma y Anna-Klara Elenström. "Pharmaceuticals in the Environment : Concentrations Found in the Water, Soil and Crops in Kampala". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-303685.
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In Kampala, the capital of Uganda, there is an extensive use of water mixed with wastewater for irrigation of crops. The water is taken from Nakivubo channel that flows through the centre of the city, and since the wastewater treatment in the city is insufficient, the channel water might contain pharmaceuticals that are spread to the farmlands and the crops that are grown in Nakivubo wetland. The aim of this Master’s thesis was to examine the concentration of some selected pharmaceuticals in water, soil and crop samples collected from Nakivubo channel and the area surrounding it. The water was analysed from five measurement points in the Nakivubo channel and Lake Victoria. The solid samples comprised of soil and crops collected from cocoyam, maize and sugar cane fields in the Nakivubo area. The pharmaceutical analyses were carried out through pharmaceutical extraction (solid phase extraction and QuEChERS) and the use of LC-MS (liquid chromatography combined with mass spectrometry). The capacities of the water and soil to reduce pharmaceuticals were analysed and a risk assessment was made in order to determine if it was harmful to drink water from Lake Victoria, the source of drinking water for Kampala, or to eat the crops that were grown in the wetland. A majority of the pharmaceuticals studied (42 substances) were detected in the water samples (29 substances). The most common pharmaceuticals detected in the water were atenolol, carbamazepine, sulfamethoxazole and trimethoprim. The antibiotics trimethoprim and sulfamethoxazole showed the highest average concentrations in the various water samples (26100 ng/l and 3790 ng/l respectively). Fewer pharmaceuticals were detected in the soil compared to the water (11 substances). The pharmaceuticals most frequently found in the soil were carbamazepine and pyrimethamine and they also had the highest average concentrations along with trimethoprim, 4.6-9.4 ng/g, 8.4-14.0 ng/g and 39.6 ng/g, respectively. No pharmaceuticals could be detected in the edible part of maize and sugar cane, but lidocaine, trimethoprim and pyrimethamine were found in detectable concentrations in the yam (on average 1.2-2.2 ng/g). A significant negative correlation could be found between carbamazepine and total suspended solids (TSS) in the water (linear regression: y = -0.67x +3.98, R2 = 0.35, p < 0.05, n = 14). The risk assessment showed that the concentrations found in the yam and water in Lake Victoria together with the average daily intake of yam and drinking water was not hazardous to the people of Kampala. However, eating more than 0.5 kg of yam daily might pose a risk with regards to pyrimethamine. On the other hand, the concentration in the yam might decrease when it is boiled, and this has not been accounted for.I Ugandas huvudstad Kampala är det vanligt att vatten blandat med avloppsvatten från den centrala Nakivubokanalen används för bevattning av grödor. Avloppsreningen i staden är bristfällig och som ett resultat släpps mycket orenat avloppsvatten ut i naturen. Det är dock oklart om det finns läkemedel i Nakivubokanalen som tas upp av jordbruksmark och grödor odlade i Nakivubos våtmark. Syftet med det här examensarbetet var att studera koncentrationen av utvalda läkemedel i vatten-, mark- och grödprover insamlade i och längs Nakivubokanalen. Prover från fem mätplatser studerades i kanalen och Victoriasjön. Mark och grödprover fanns tillgängliga som samlats in från jams-, sockerrör- och majsfält i och kring Nakivubos våtmark. Läkemedelsanalyserna genomfördes med hjälp av läkemedelsextraktion i form av fastfasextraktion och QuEChERS samt LC-MS (vätskekromatografi kombinerat med masspektrometri). Utöver läkemedelsanalysen studerades markens och vattnets förmåga att rena läkemedel. Det utfördes även en enkel riskbedömning för att se om det var farligt att äta grödor odlade i våtmarken eller dricka vatten från Victoriasjön, som är Kampalas dricksvattenkälla. De flesta (29 st) av de 42 studerade läkemedlen detekterades i vattenproverna. De vanligast förekommande läkemedlen i vattnet var atenolol, karbamazepin, sulfametoxazol, och trimetoprim. Trimetoprim och sulfametoxazol hade de högsta koncentrationerna i de olika mätpunkterna i vattnet i medeltal, 26 100 ng/l respektive 3790 ng/l. I marken detekterades 11 av de 42 läkemedelsämnena. De vanligast detekterade läkemedlen i marken var karbamazepin samt pyrimethamine och det var också dessa som hade högst koncentrationer i medeltal, tillsammans med trimetoprim. Dessa tre läkemedel hade koncentrationer på 4,6-9,4 ng/g; 8,4-14,0 ng/g respektive 39,6 ng/g. Inga läkemedel kunde detekteras i majsen och sockerrören, men jamsen hade detekterbara koncentrationer av både lidokain, trimetoprim och pyrimethamine (1,2-2,2 ng/g i medeltal). I vattnet erhölls ett signifikant negativt samband mellan karbamazepin och totalt suspenderat material (linjär regression: y = -0,67x + 3,98; R2= 0,35; p < 0,05; n = 14). Riskanalysen visade att det inte bör vara farligt att äta jamsen eller dricka vattnet från Victoriasjön givet de koncentrationer som uppmättes och de mängder jams och vatten som förtärs dagligen. Det kan dock utgöra en risk att äta mer än 0,5 kg jams om dagen.
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Olds, Donald. "The effect of degree, duration, and timing of water deficit stress on the growth, nutrition, and water use of Phaseolus Vulgaris L. /". Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63899.
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Doliber, Sarah Rebecca. "Groundwater Surface Trends in the North Florence Dunal Aquifer, Oregon Coast, USA". PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/530.
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The North Florence Dunal Aquifer is the only feasible source for drinking water for the coastal city of Florence, Oregon and Florence's Urban Growth Boundary. High infiltration rates and a shallow groundwater table leave the aquifer highly susceptible to contamination from septic tank effluent, storm runoff, chemical fertilizers and recreational ATV use throughout the dunes. Public interest in the quality and quantity of the aquifer water has been sparked since the City of Florence received a grant from the Environmental Protection Agency for a watershed protection and restoration project. Delineation of the shallow groundwater surface and its relationship to the surface water bodies within the dunes is crucial in protecting this drinking water source from contamination. This thesis project created a GIS representation of the shallow groundwater elevation and associated prediction error map. Surface water bodies were confirmed as window lakes into the dunal aquifer and no signs of perched aquifer conditions were observed between Holocene and Pleistocene dunes. Ground Penetrating Radar, well data provided by the city of Florence and LiDAR were the primary sources for data collection.
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Wagner, Derrick Lee. "Hydrogeologic Characterization of Dutch Canyon, Scappoose, Oregon". PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1020.
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Dutch Canyon is located directly west of the City of Scappoose in Columbia County Oregon. This area is proximate to Highway 30, a major access corridor to downtown Portland, and is experiencing a population increase, which is expected to continue and likely accelerate. As a result, there is growing pressure on water resources. Individual and community efforts to utilize groundwater resources have been hampered by generally poor groundwater yields and water quality concerns outside of the Columbia River corridor and a lack of published hydrogeologic information for the region.
The intent of this study is to identify the water-bearing units present in Dutch Canyon and to characterize water quality within these units. The physical hydrogeology of Dutch Canyon was assessed mainly through the collation of 196 local well reports that contained lithologic information from which individual hydrostratigraphic units were identified and characterized. Hydraulic parameters for individual units were estimated using pump rates and drawdowns provided in select well reports. Water quality for the units identified was assessed through the collection of 48 samples of well, spring, and stream water from Dutch Canyon. Measurements of pH, specific conductivity, temperature, dissolved oxygen, reduction potential, and alkalinity were recorded in the field and samples were analyzed for major ions, arsenic, and stable isotopes.
The major water-bearing units of Dutch Canyon were separated into five physically distinct hydrostratigrapic units: the lower, middle, and upper units of the sedimentary Lower Miocene Scappoose Formation, and the Wapshilla Ridge and Ortley members of the Lower to Middle Miocene Grande Ronde Basalt. Groundwater flow likely occurs in discrete, relatively thin (~2- to 10-m thick) zones within the Grand Ronde Basalt members. These units only occur along the slopes and ridges of Dutch Canyon west of the Portland Hills Fault, which parallels the eastern margin of the study area. The Scappoose Formation units contain clay- and silt-rich layers and lenses that limit the useable aquifer volume and vertical movement of groundwaters. In general, all hydrostratrigraphic units east of the Portland Hills Fault have low transmissivities and water wells completed in each of them are commonly low- yielding wells, though there are some exceptions.
Geochemically, the lower and middle units of the Scappoose Formation were similar to one another with many wells yielding groundwater with high total dissolved solids (TDS) contents (mean TDS = 330 mg L-1; n = 27). Nearly 20% of the wells sampled that were screened in these units (5 of 27) yielded groundwater that exceeded the U.S. Environmental Protection Agency's National Secondary (non-enforceable) Drinking Water Regulation standard of 500 mg L-1 TDS. The upper unit of the Scappoose Formation and the overlying Grande Ronde Basalt members generally yield water with lower TDS contents (mean < 200 mg L-1; maximum = 342 mg L-1; n = 20).
Groundwater resources in Dutch Canyon are limited and low well yields are common. The primary water quality concern is saline water, which is generally found in the lower and middle units of the Scappoose Formation near the valley floor. Low recharge rates determined from hydrograph analysis of stream discharge measurements are consistent with the geology and steep terrain of the area and further limit the available groundwater and the degree of flushing of what may be connate waters in the deeper units.
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Berger, Christopher John. "Water Quality Modeling of the Tualitin River". PDXScholar, 1993. https://pdxscholar.library.pdx.edu/open_access_etds/4742.
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Water quality problems related to excessive algal growth, high nutrient loading, and low flows have been occurring along Oregon's Tualatin River. The Tualatin River is 86 miles long and has a drainage basin of 711 square miles. The drainage basin incorporates forest, agricultural, and urban areas. Located in the Portland metropolitan area, these problems have been acerbated by the effects of urban growth. To help analyze pollution control alternatives, a river model study, funded by the Oregon Department of Environmental Quality (DEQ}, was undertaken. An in-stream model of hydraulics and water quality was developed. The Corps of Engineer's CE-QUAL-W2 model, a twodimensional, laterally averaged, dynamic model of hydrodynamics and water quality was applied to the Tualatin system. Calibration of the main pool model of the Tualatin River was from field data taken during June through August of 1991. Verification of the model was performed from field data taken during the summer of 1990. After calibration and verification of the model, management alternatives were evaluated in order to achieve DEQ mandated water quality standards. Environmental performance criteria were determined to evaluate differences between model scenarios. Management alternatives focused on the reduction of point and non-point sources of pollution, flow augmentation, and structural changes in the river system, such as removal of the Lake Oswego Diversion Dam.
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Strohmenger, Petronella Hermina Elizabeth. "Interactive effects of a calcium and magnesium sulphate enriched waste water on crop growth and nutrition". Diss., University of Pretoria, 2001. http://hdl.handle.net/2263/23599.
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The coal industry of Mpumalanga Province is faced with the problem of developing cost effective ways of using large volumes of calcium and magnesium sulphate enriched waste waters. Use of the waste waters for agricultural production may contribute as a stabilising factor with regard to yields in this high potential agricultural area. The objectives of this study were to determine the effect of such waste waters on yield and to compare crop response to calcium and magnesium sulphate salinity at different nutrient levels. Two separate glasshouse experiments were conducted. Wheat (Triticum aestivum L. cv. SST 825) was grown in calcium and magnesium sulphate salinised nutrient solutions (Ca:Mg 2: 1) with differential levels of NO3, NH4, P and K. A soil pot experiment was subsequently conducted with maize (Zea mays, cv. PAN 6256), three gypsum and magnesium sulphate salinity levels and a 6 x 2 x 3 factorial combination of N, P and K. Calcium and magnesium sulphate salinity decreased the biomass production of both crops. This was mainly due to interactions of Mg with the uptake of essential nutrients in wheat and a Mg toxicity andlor Ca deficiency induced by high levels of Mg andlor SO4 in maize. The application of NO3, NH4, and K at rates different from the level considered beneficial for non-saline conditions improved wheat growth under sulphate saline conditions. Strongly inhibitory salinity levels controlled the maize yield of the highest salinity treatment regardless of the level of fertiliser application. A beneficial effect of higher NH4 supply was observed in both experiments. This can be ascribed to the antagonistic effect that NH4 exerted on Mg concentrations in plants (both experiments) and SO4 (soil pot experiment) and/or to a higher N-utilization efficiency where N was supplied as NH4 compared to NO3. Differential application levels of P had no effect on the yield of wheat. Phosphorus concentrations in maize were marginal to low, even at extremely high soil Bray I-P levels. This was probably caused by the precipitation of P as insoluble calcium phosphate complexes in the soil andlor between the free space of the cortex cells of plant roots. These results could also indicate that the Bray I extraction method does not give a true reflection of plant available P in sulphate saline soil. Further experimentation is needed to verify these results under field conditions and determine the optimal rate, method and timing of especially NH4 and PO4 fertilisers when irrigating crops with these calcium and magnesium sulphate enriched waste waters.Dissertation (MSc (Plant Production and Soil Science))--University of Pretoria, 2007.
Plant Production and Soil Science
unrestricted
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Subedi-Chalise, Kopila. "Impacts of Crop Residue and Cover Crops on Soil Hydrological Properties, Soil Water Storage and Water Use Efficiency of Soybean Crop". Thesis, South Dakota State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10265200.
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Cover crops and crop residue play a multifunctional role in improving soil hydrological properties, soil water storage and water use efficiency (WUE). This study was conducted to better understand the role of crop residue and cover crop on soil properties and soil water dynamics. The study was conducted at the USDA-ARS North Central Agricultural Research Laboratory, located in Brookings, South Dakota. Two residue removal treatments that include low residue removal (LRR) and high residue removal (HRR) were established in 2000 with randomized complete block design under no-till corn (Zea mays L.) and soybean (Glycine max L.) rotation. In 2005, cover crop treatments which include cover crops (CC) and no cover crops (NCC) were integrated into the overall design. Soil samples were collected in 2014, 2015 and 2016. Data from this study showed that LRR treatment resulted in lower bulk density (BD) by 7 and 9% compared to HRR in 2015 and 2016, respectively, for 0-5 cm depth. Similarly, LRR treatment significantly reduced soil penetration resistance (SPR) by 25% in 0-5 cm depth compared with HRR treatment. In addition to this, LRR treatment significantly increased soil organic carbon (SOC) concentrations and total nitrogen (TN) by 22 and 17%, respectively, in 0-5 cm. Similarly, CC treatment resulted in lower BD and SPR by 7% and 23%, respectively, in 0-5 cm depth in 2015 compared with NCC treatment. The LRR significantly increased soil water infiltration by 66 and 22% compared to HRR in 2014 and 2015, respectively. Similarly, the CC treatment significantly increased infiltration by 82 and 22% compared to the NCC in 2014 and 2015, respectively. The significant impact of a crop residue was observed on soil water retention (SWR) in 2014 and 2015 for the 0-5 cm depth. The LRR and CC treatments increased the soil volumetric moisture content (VMC) and soil water storage (SWS) on the surface 0-5 cm depth. However, the trend was not always significant during the growing season. The CC treatment significantly impacted the soybean yield by 14% and WUE by 13% compared with NCC treatment. Some interaction of residue by cover crops was observed on BD, SPR, VMC, and SWS, which showed that the use of cover crops with LRR can be beneficial in improving the soil properties.
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Bunyolo, A. M. "Effects of fertilizer nitrogen and water supply on growth and yield of the potato crops". Thesis, University of Reading, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379220.
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Rein, William Henry. "Stock plant nutrition and stem cutting water relations during propagation of four woody nursery crops". Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41616.
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To evaluate the effects of stock plant nutrition and propagation medium moisture content on stem cutting propagation, two separate studies were conducted. In one study, stem cuttings of Juniperus horizontalis Moench ‘Wiltonii’, Rhododendron (Lindl.) Planch ‘Hino-Crimson’, and Ilex crenata ‘Helleri’, were propagated in 1 peat : 1 perlite (v/v) at 125 %, 250 %, 375 %, 500 %, and 625 % moisture. Stem cutting survival and rooting, midday xylem water potential, and basal water uptake all generally increased with increasing medium moisture level. Incidence of cutting basal rot was not directly related to medium moisture level, but was related to species and growth stage of the stock plant. Basal water uptake by cuttings was highest during the first few days after insertion and thereafter decreased until root emergence. Propagation was most successful in the wettest medium (625 %).
In a second study, containerized stock plants of Ilex crenata Thunb. ‘Rotundifolia’ were liquid-fertilized with 25, 50, 100, 200, and 300 mg N · liter⁻¹ in two forms (100 % NH₄NO₃ or 50 % Urea + 50 % NH₄NO₃) in a factorial treatment design. Percent rooting of stem cuttings decreased linearly with fertilizer rate. Leaf and stem percent N increased from suboptimal to excessive levels with fertilizer rate. Total nonstructural carbohydrates (TNC) levels increased in leaves and remained constant in stems with increasing fertilizer rate. Stem cutting percent moisture was highly correlated with fertilizer rate. The form of N applied made no statistical difference in these trends. The decrease in percent rooting with increasing fertilizer rate was attributed to increases in shoot growth activity.Master of Science
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Oliva, Ruben N. "Water relations in red and white clover seed crops". Thesis, 1992. http://hdl.handle.net/1957/37638.
Texto completoResumen
Both red (Trifolium pratense L.) and white (Trifolium repens L.) clover
seed yields can be highly variable and low in western Oregon. The objectives of
this study were to: i) determine crop water requirements and supplemental
irrigation timing, and ii) quantify the effects of soil and water status on
inflorescence production, seed yield and seed yield components for red and
white clover seed crops. In each species, five supplemental irrigation treatments
were applied in 1990 and 1991 to first and second year seed crops grown on a
Woodburn silt loam (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis,
OR. Non-irrigated controls were also maintained.
In red clover, increased plant water stress reduced the duration of the
season-long bud and flower production, stem length, potential floral capacity
(PFC), and seed yield (SY). Root rot index (RRI) increased with increasing
levels of plant water stress, indicating that supplemental water applications
reduced second-year root rot severity. The reduction in SY from increasing
plant water stress was primarily caused by a decrease in floral fertility, and less
conclusively by reductions in inflorescence number per unit area. One irrigation
to fill the soil active profile during peak flowering provided adequate water to
maintain efficient seed production.
In white clover, SY was maximum in 1990 when water application was
delayed until 68% of the available soil-water was used by the crop which
maintained an even flush of flowers and restricted vegetative growth. In 1991,
all irrigation treatments yielded the same or less than the non-watered control.
This was due to the excessive vegetative growth from stolons that had grown
between the planted rows the previous and present crop year. In both years
excessive amounts of irrigation water favored profuse vegetative growth and
reduced SY. Inflorescence density was increased by constraining soil-water in
1990 and was the yield component that most affected SY both years.
Crop water stress index (CWSI) was a useful indicator of plant stress
status and can be used to schedule irrigations in red and white clovers grown
for seed under typical climatic conditions of western Oregon.Graduation date: 1993
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Gochis, David J. "Estimated plant water use and crop coefficients for drip-irrigated hybrid polars". Thesis, 1998. http://hdl.handle.net/1957/33819.
Texto completoResumen
Estimations of plant water use can provide great assistance to growers, irrigators,
engineers and water resource planners. This is especially true concerning the introduction
of a new crop into irrigated agriculture. Growing hybrid poplar trees for wood chip stock
and veneer production under agronomic practices is currently being explored as an
alternative to traditional forestry practices. To this author's knowledge, no water use
estimates or crop coefficients, the ratio of a specified crop evapotranspiration to a
reference crop evapotranspiration, have been verified for hybrid poplars grown under drip
irrigation.
Four years of weekly, neutron probe measured, soil water data were analyzed to
determine averaged daily, monthly and seasonal plant water use, or crop
evapotranspiration. The plantation studied was located near Boardman, Oregon on the
arid Columbia River Plateau of North-Central Oregon. Water was applied by periodic
applications via drip irrigation. Irrigation application data, weekly recorded rainfall and
changes in soil water content permitted the construction of a soil water balance model to
calculate weekly hybrid poplar water use. Drainage was estimated by calculating a
potential soil water flux from the lower soil profile. Sites with significant estimated
potential drainage were removed from the analysis so that all sites used in the development
coefficients were calculated using reference evapotranspiration estimates obtained from a
nearby AGRIMET weather station. Mean crop coefficients were estimated using a 2nd
order polynomial with 95% confidence intervals. Plant water use estimates and crop
curves are presented for one, two and three year old hybrid poplars.
Numerical simulation of irrigation practices was attempted using weekly soil water content and soil physical characterization data. Parameter optimization and numerical simulations were attempted using the HYDRUS-2D Soil Water and Solute Transport model. Parameter optimization and numerical simulations were largely unsuccessful due to lack of adequate soil physical and root zone system representation and dimensional differences between drip irrigation processes and the model design used in this study.Graduation date: 1998
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Al-Sayagh, Khalid Faraj. "Procarbazone-sodium effect on rotational crops and its dissipation". Thesis, 1998. http://hdl.handle.net/1957/33953.
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Minshew, Hudson F. "Nitrate leaching and model evaluation under winter cover crops". Thesis, 1998. http://hdl.handle.net/1957/33330.
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