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1
Peacock, Catherine. "Reedbed hydrology and water requirements." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/3836.
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Stodmarsh National Nature Reserve includes the largest reedbed in Southern England and is an important habitat for breeding waders and several rare bird species, including Bitterns. A succession of drought years in the 1990s brought the issue of the hydrology and water requirements of the wetland to the attention of managers and there is concern about future water supplies to the reserve. This study aims to calculate the amount of water required by the site in order to maintain optimum habitat conditions. The greatest area of uncertainty in the water balance is the evapotranspiration rate of the reedbeds and therefore a secondary aim is to increase understanding of this flux. Detailed hydrological measurements were carried out over two years to establish the water balance of the site. Evapotranspiration was measured using the Bowen ratio technique, accompanied by additional physiological and meteorological measurements. Results showed that evapotranspiration from reeds was generally less than reference evapotranspiration and that stornatal resistance was the most important factor controlling evapotranspiration rates. The hydrology of the site was modelled using a thirty year historical data series to quantify the return periods of flood and drought conditions of different severity. These were used to predict water resource requirements and availability and confidence limits were attached to the results. In 70% of years, summer deficits in the rainfall-evapotranspiration balance require the addition of water from the Lampen Stream. In 10% of these years, the entire surmner discharge of the Lampen Stream would be insufficient to meet site water requirements and an additional source of water is required. Competition with other water users and limits on abstraction will increase the number of years an additional water source is required. In addition future climate change is likely to increase summer water requirements whilst decreasing resource availability.
2
Perez, Jose 1950. "WATER AND NITROGEN EFFECTS ON THE CROP WATER STRESS INDEX OF COTTON." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275339.
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Stults, Erica Suzanne. "Minimizing Water Requirements for Electricity Generation in Water Scarce Areas." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-dissertations/265.
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Renewable energy technologies are infrequently evaluated with regard to water use for electricity generation; however traditional thermoelectric power generation uses approximately 50% of the water withdrawn in the US. To address problems of this water-energy nexus, we explore the replacement of existing electricity generation plants by renewable technologies, and the effect of this replacement on water use. Using a binary mixed integer linear programing model, we explore how the replacement of traditional thermoelectric generation with renewable solar and wind technologies can reduce future water demands for power generation. Three case study scenarios focusing on the replacement of the J.T. Deely station, a retiring coal thermoelectric generation plant in Texas, demonstrate a significant decrease in water requirements. In each case study, we replace the generation capacity of the retiring thermoelectric plant with three potential alternative technologies: solar photovoltaic (PV) panels, concentrated solar power (CSP), and horizontal axis wind turbines (HAWT). The first case study, which was performed with no limits on the land area available for new renewable energy installations, demonstrated the water savings potential of a range of different technology portfolios. Our second case study examined the replacement while constrained by finite available land area for new installations. This demonstrated the trade-off between land-use efficient technologies with water-use efficiency. Results from our third case study, which explored the replacement of a gas-fired plant with a capacity equivalent to the J. T. Deely station, demonstrated that more water efficient thermoelectric generation technologies produce lower percentages of water savings, and in two scenarios the proposed portfolios require more water than the replaced plant. Comparison of multiple aspects of our model results with those from existing models shows comparable values for land-use per unit of electricity generation and proposed plant size. An evaluation of the estimated hourly generation of our model’s proposed solution suggests the need for a trade-off between the intermittency of a technology and the required water use. As we estimate the “costs� of alternative energy, our results suggest the need to include in the expression the resulting water savings.
4
Dalton, James A. "Contribution of upward soil water flux to crop water requirements." Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/344938/.
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Kazemi, Hossein V. "Estimating crop water requirements in south-central Kansas." Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9859.
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6
Cooper, T. "The effect of water potential on Acanthamoeba castellanii." Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233058.
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Barnes, Frank. "Estimating Crop Water Requirements in Arizona and New Mexico." Thesis, The University of Arizona, 2011. http://hdl.handle.net/10150/203501.
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Relevant methods for estimating reference crop evaporation and crop evaporation for selected, pertinent crops growing in the semiarid environments of Arizona and New Mexico are investigated. Daily evaporation estimates over the period 2000-2010 are calculated using standard meteorological data from 35 weather stations. Compared to the FAO-56 Penman-Monteith reference evapotranspiration estimate, the Hargreaves and Priestley-Taylor equations overestimate by 5-15% while the temperature-based Blaney-Criddle method currently used in New Mexico underestimates by 8-13%, on average, the discrepancy being most severe in highly advective regions. Crop evaporation estimates are compared to the one-step Matt-Shuttleworth approach. The Blaney-Criddle method systematically underestimates crop evaporation by 7-30%, while underestimation using the climatically adjusted FAO-56 crop coefficient approach is 1-8% for short crops but ~20% for tall pecan and citrus orchards grown at atmospherically arid locations. Crop surface resistances derived using the Matt-Shuttleworth approach at Fabian Garcia in southern New Mexico compare favorably to literature values.
8
AVVEDIMENTO, STEFANIA. "Methodologies for Ensuring Quality Requirements in Water Distribution Networks." Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1457235.
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Davis, Simon. "Fire Fighting Water: A Review of Fire Fighting Water Requirements A New Zealand Perspective." University of Canterbury. Civil Engineering, 2000. http://hdl.handle.net/10092/8346.
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This paper seeks to identify a linkage between the requirements for fire fighting water and building design. This paper reviews existing methods to calculate fire fighting water requirements and comments on their applicability in the context of fire service tactics.
Defining what constitutes an adequate supply of water for fire fighting is also central to planning fire service operations.
The provision of water for fire fighting operations is a significant infrastructure cost borne by the community as the fire fighting requirements dominates the sizing of the network elements.
This paper reviews work undertaken to date and seeks to offer a methodology that supports the fire engineering approach being adopted in performance based building codes.
10
Tannenbaum, Stacey L. "An Investigation into Equations for Estimating Water Requirements and the Development of New Equations for Predicting Total Water Intake." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/338.
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The primary purpose of this study was to investigate agreement among five equations by which clinicians estimate water requirements (EWR) and to determine how well these equations predict total water intake (TWI). The Institute of Medicine has used TWI as a measure of water requirements. A secondary goal of this study was to develop practical equations to predict TWI. These equations could then be considered accurate predictors of an individual’s water requirement.
Regressions were performed to determine agreement between the five equations and between the five equations and TWI using NHANES 1999-2004. The criteria for agreement was 1) strong correlation coefficients between all comparisons and 2) regression line that was not significantly different when compared to the line of equality (x=y) i.e., the 95% CI of the slope and intercept must include one and zero, respectively. Correlations were performed to determine association between fat-free mass (FFM) and TWI. Clinically significant variables were selected to build equations for predicting TWI. All analyses were performed with SAS software and were weighted to account for the complex survey design and for oversampling.
Results showed that the five EWR equations were strongly correlated but did not agree with each other. Further, the EWR equations were all weakly associated to TWI and lacked agreement with TWI. The strongest agreement between the NRC equation and TWI explained only 8.1% of the variability of TWI. Fat-free mass was positively correlated to TWI. Two models were created to predict TWI. Both models included the variables, race/ethnicity, kcals, age, and height, but one model also included FFM and gender. The other model included BMI and osmolality. Neither model accounted for more than 28% of the variability of TWI. These results provide evidence that estimates of water requirements would vary depending upon which EWR equation was selected by the clinician. None of the existing EWR equations predicted TWI, nor could a prediction equation be created which explained a satisfactory amount of variance in TWI. A good estimate of water requirements may not be predicted by TWI. Future research should focus on using more valid measures to predict water requirements.
11
Schuch, Ursula, and Edward C. Martin. "A Study of Irrigation Requirements of Southwestern Landscape Trees." College of Agriculture, University of Arizona (Tucson, AZ), 2017. http://hdl.handle.net/10150/625295.
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12 pp.Trees are an important component of our landscapes, providing many benefits from shade to cleaning the air. Large, mature trees provide the greatest benefits in urban landscapes compared to smaller, younger trees and it is therefore important to ensure that trees in our urban forests receive the amount of water they need to develop into healthy, mature specimens.
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Gay, Alanis Leon F. "Measuring Energy Efficiency of Water Utilities." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34231.
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Water infrastructure systems worldwide use large amounts of energy to operate. Energy efficiency efforts are relevant because even relatively small gains in efficiency have the potential to bring significant benefits to these utilities in terms of financial savings and enhanced sustainability and resiliency. In order to achieve higher efficiency levels, energy usage must be measured and controlled.
A common tool used to measure energy efficiency in water utilities and perform comparisons between utilities is metric benchmarking. Energy benchmarking scores are intended to measure how efficient water systems are among their peers, in a simple and accurate fashion. Although many different benchmarking methods are currently used, we chose to use the segregated benchmarking scores proposed by Carlson on his research report from 2007 (Carlson, 2007).
The research objective is to improve these production energy use and treatment energy use benchmarking scores by analyzing the systemâ s particular characteristics that might skew the results, such as topology, water loss and raw water quality. We propose that benchmarking metrics should be always used within a particular context for each specific utility being analyzed. A complementary score (Thermodynamic Score) was developed to provide context on how energy efficient is the utility not only compared with other utilities, but also compared with the potential maximum efficiency the utility can reach itself.
We analyzed eight utilities from Virginia to obtain production and treatment energy use benchmarking scores and also thermodynamic scores using the minimum required energy approach. Benchmarking scores were skewed in 50% of the studied utilities. This means that benchmarking scores should never be used as a black box. The thermodynamic score proved to be useful for measurement of energy efficiency of a water utility on its production phase. In addition, some utilities can detect significant financial saving opportunities using the minimum required energy analysis for production operations.Master of Science
13
Martinez, M. C. C. "Studies on water soluble vitamin requirements in Cichlasoma urophthalmus (Gunther 1862)." Thesis, University of Stirling, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379513.
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Goeft, Ute. "Water centrality for water and society." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/21.
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The current approach to water management in Western societies, including Australia, is based on allocating water between different users. Appropriate for commercial uses, this commodity view of water has proved difficult for the inclusion of environmental and social concerns. Issues, such as which aspects have precedence, how much water should be allocated to each and how to make trade-offs in cases of insufficient water, pose problems that are yet to be worked out. In addition, there is a lack of knowledge regarding the identification of environmental as well as social water needs. The latter has prompted the writing of this thesis. A closer look at the neglected social water needs reveals the complete permeation of water into all areas of human life, from the basics of survival and health to the ethical and spiritual spheres. All these social aspects, or values, of water, should be integral to water management.
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Van, Der Walt Marthinus. "Development of a land use-based spatial water requirements model for the Berg Water Management Area." Master's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/27071.
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This study was conducted to investigate the requirements for the spatial modelling of current and future water demand in the Berg River Water Management Area in the Western Cape of South Africa in order to produce a prototype model from which annual water requirements could be computed and spatially visualised. To accomplish this the spatial distribution of water demand within the study area was first investigated. The data required to perform spatial water demand modelling of diverse land uses and socio-economic activities were evaluated. Finally, the question of improving spatial water demand modelling at the catchment scale was considered from both a systems design and a technical perspective. The resulting model consists of two main modules; one performing a rudimentary monthly soil water balance to obtain monthly and annual irrigation requirements, and another applying preconfigured determinant layers derived from land use to town zone layers in order to determine annual urban water use intensities per areal unit. The resulting model prototype follows a sequential workflow based on a series of components that combine to produce a spatial overview of water use intensity within the study area. Water demand was found to be predominantly irrigated agriculture in the upper reaches of the Berg (mainly wine grape) and was found to be dominated by intensive industrial users in the central and lower reaches. The model was designed so that new data could be introduced in order to expand the system where required, as well as allowing for updated datasets to be incorporated as they become available. Due to the uncertainties inherent in the modelling and approximation of real world phenomena, the importance of establishing a set of structured, stable, predefined user requirements and system specifications were noted as a fundamental requirement for improving model development and design efficiency and ensuring model validity. It was further found that incorporating additional datasets, covering parameters related to the system, may serve to improve model accuracy, but could easily lead to compounded errors if not correctly parameterised or adequately validated.
16
IMANI, BEHZAD. "ESTIMATION OF WATER CONTENT, TRANSPIRATION RATE, AND WATER POTENTIAL OF COTTON FROM STEM DIAMETER MEASUREMENTS USING A LINEAR VOLTAGE DIFFERENTIAL TRANSFORMER." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184005.
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The Linear Voltage Differential Transformer (LVDT) is an accurate sensor for stem diameter measurements. Based on the results of this dissertation it was found that stem diameter [mm] was related to water content [grams] of the cotton crop by the following equation: W(D) = 0.114(D)³ˑ¹⁸² Also the ratio of stem diameter contraction rate to the rate of water loss in cotton was experimentally determined to be: (dW/dt)/(dD/dt) = (0.166 [g min⁻¹])/(0.535 [μm min⁻¹]) = (.0469% per minute)/(.0039% per minute). Similarly the cellular water potential was derived to be a non linear function of stem diameter in cotton: ψ(t) - ψₒ = 2 ε ln (D(t)/ Dₒ) + πₒDₒ² [(1/D²(t)) – (1/Dₒ²)]. Based on this work, the grower can estimate the water content, transpiration rate and water potential of the cotton crops via stem diameter measurements. Moreover, a computer system can be implemented to remotely keep track of the water status of the field, and control the irrigation system. A general model was proposed to quantify the nature of input-output relation of the cotton crop. A proposed simplified model based on stem diameter is also introduced. The stem diameter measurements can be used as an index for estimation of cotton's water content, transpiration rate, and water potential. These three parameters and the proposed simplified model established a plant based predictive irrigation scheduling technique. The electrical output of the LVDT was quite noisy. To remove the noise and demodulate the data, two cascade circuits were designed and implemented. First, the external output circuit removed the noise and isolated the LVDT. Second, the LVDT signal conditioner demodulated the phase information from the secondary windings which were produced by the movement of the rod. By the implementation of these circuits, 1 m of the rod displacement resulted in 1.14 mv of dc voltage changes in the output.
17
Doria, Rufa. "Impact of climate change on crop water requirements in Eastern Canada." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104583.
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Crop production is highly dependent upon weather; therefore, future climate change could adversely affect the burgeoning global population. The primary objective of this study was to predict the consequences of climate change on agriculture. Since current climate projections use general circulation models (GCMs) on a global scale, a statistical downscaling model (SDSM) was used to downscale these outputs into a local scale, essential for reliable crop model simulations.By linking predicted changes in local climate to soil properties and crop characteristics through field and laboratory studies, thresholds of soil moisture content for efficient irrigation scheduling were defined, and an irrigation requirements model (IRM) was developed. Using the IRM, irrigation was triggered when soil moisture was 18 or 24 mm for peaches grown in clay and sandy soils, respectively, and was also triggered at 56 mm for grapes grown in clay soils. It was noteworthy that the IRM reduced irrigation needs by 20 to 25% without affecting yield of peaches (50 to 60 kg/tree). Regarding predicted increases in temperatures and variability in precipitation, the SDSM-HadCM3 A2 scenario forecast the greatest increases, namely ~3.5 and ~2.5°C in average monthly maximum and minimum temperatures, respectively, during the growing season, compared to a 1961-1990 base period. Moreover, precipitation events were also predicted to be more frequent (8 to 30%) and intense (10 to 50%) during crop growing months.With these future climate change scenarios, irrigated peach yield could increase 5 to 20%, since actual tree transpiration reached 0.8 kg/h (compared to a maximum of 0.4 kg/h without irrigation). Furthermore, with irrigation, fruit firmness, the best indicator of ripening and predictor of peach storage potential, is expected to improve by 20% over the current value of 340 kPa.The most novel aspect of this study was development of the IRM, and its prediction of optimal irrigation needed to sustain or increase crop yield and quality, and concurrently conserve water.La production agricole est très dépendante du climat; par conséquent, les futurs changements climatiques globaux pourraient avoir des effets adverses sur la population mondiale en plein essor. L'objectif principal de cette étude était de prédire les conséquences du changement climatique sur l'agriculture. Puisque les projections climatiques actuelles utilisent des modèles de circulation générale à une échelle globale, un modèle statistique de réduction (MSR) a été utilisé pour réduire ces données à l'échelle locale, ce qui est essentiel pour des simulations de production agricole.En reliant les changements du climat locaux prédits (modélisation) aux propriétés du sol et les caractéristiques des cultures (études sur le terrain et en laboratoire), les seuils du contenu en humidité du sol pour la planification d'un horaire d'irrigation efficace ont été définis, et un modèle de besoin en irrigation (MBI) a été développé. En utilisant ce modèle, l'irrigation était déclenchée lorsque l'humidité du sol était de 24 ou 18 mm pour les pêchers croissant en sols sablonneux ou argileux, respectivement, et a été déclenchée à 56 mm pour les vignes croissant en sol argileux. Il était remarquable que le MBI a réduit le besoin en irrigation de 20 to 25% sans affecter le rendement en pêches (50 to 60 kg/arbre).Concernant les augmentations de températures et les variabilités de précipitations prédites, le scénario SDMS-HadCM3 A2 prédit les plus fortes hausses, environ 3.5 et 2.5oC en moyenne pour les températures mensuelles maximum et minimum, respectivement, pendant la saison de croissance (comparé à une période de base 1961-1990). De plus, des précipitations plus fréquentes (8 to 30%) et plus intenses (10 to 50% durant les mois de croissance ont aussi été prédites.Avec ces scénarios de changements climatiques futurs, le rendement en pêches irriguées pourrait augmenter de 5 to 20%, puisque la transpiration des arbres a atteint 0.8 kg/h (comparé à un maximum de 0.4 kg/h sans irrigation). De plus, avec l'irrigation, la fermeté des fruits, le meilleur indicateur du mûrissement et prédicateur du potentiel d'entreposage des pêches, devrait s'améliorer de 20% (valeur actuelle, 340 kPa).L'aspect le plus novateur de cette étude a été le développement du modèle MBI, qui a prédit l'irrigation optimale requise pour maintenir ou augmenter le rendement et la qualité des cultures tout en conservant l'eau.
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Snyder, James Riley. "Construction requirements of the water supply of Constantinople and Anastasian Wall." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/8257.
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With the end of Western Roman rule and the emergence of new polities in the medieval world, it has been assumed that the technology of mortar reverted to a weak and friable building material. However, this period brought about the implementation of large-scale construction projects that still remain as a testament to their high quality construction techniques and materials. In order to meet the needs of its growing populace, the infrastructure of the new capital city of Constantinople was bolstered by these projects, many rivaling the scale and intricacy of Imperial Rome. A prime example of this is the extensive channel networks of the fourth and fifth centuries, built in the hinterland of Constantinople to supply fresh water from springs hundreds of kilometres away. In addition, the sixth century Long Wall of Thrace was built from the Black Sea to the Sea of Marmara as a first line of defense against increased aggression. This project examines the tradition of monumental construction in the Late Antique and early Byzantine world through laboratory analysis of mortars and valuations of the structural makeup of the Water Supply of Constantinople and Anastasian Wall. By investigating the material technology, scale, and labour requirements of these systems, a better understanding can be gained of two of the largest building project of the early medieval period.
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Clark, Lee J., E. Niel Biggs, and Laura Rose. "Wheat Water Requirements and Typical Irrigation Efficiences in the Safford Area." College of Agriculture, University of Arizona (Tucson, AZ), 1985. http://hdl.handle.net/10150/200511.
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Alou, Abdourahamane 1959. "Vegetative physiology of cotton as related to the Crop Water Stress Index." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276939.
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This study was undertaken to investigate Gossypium hirsutum L. reproductive physiology and metabolic activities as they relate to the Crop Water Stress Index. Five treatments were established based on the CWSI. These were the maximum stress levels allowed for each treatment. The indices investigated were .16, .35, .36, .40, and .62. Daily tagging of opened flowers in each treatment was conducted throughout the season. Diffusive resistance, transpiration, apparent photosynthesis, and yield were measured. There was no significant difference in treatment yield. Plants irrigated at stress level either below .30 or above .40, tended to yield relatively low compared to plants maintained between .30 and .40. Floral production, abscission and boll retention were negatively correlated to CWSI. Negative relationships were also found between apparent photosynthesis, transpiration, leaf area and CWSI. A two day lag response was observed between a decrease in CWSI values resulting from irrigation, and daily flowering increase.
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Ashley, Roger Orrin 1953. "The performance of selected small grain cultivars under an irrigation gradient." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277153.
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Differential adaptations of barley (Hordeum vulgare L.) and wheat (Triticum spp.) genotypes suggest that they be evaluated under multi-environmental conditions. The objectives of this study were to determine if small grain genotypes, bred for various moisture conditions, respond differently in terms of yield, water use, and rooting pattern to contrasting moisture conditions. Eight small grain genotypes were compared under a gradient of water from 89 to 404 mm (plus 254 mm of stored water) in a field study at Marana, AZ. A barley bred for low input conditions had greater root density in the subsoil and used moisture earlier in the season when compared to a high input barley (WestBred Gustoe). The cultivars bred for high input conditions required more water for optimum yield compared to those bred for low input conditions.
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Metzler, F., S. Husman, and R. Wegener. "Lint Yield Response to Varied Levels of Water Stress and Consumptive Water Use Requirements of Upland Cotton." College of Agriculture, University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/210946.
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Lint yield response to varied Management Allowed Depletion Levels (MADL), and consumptive water use rates were determined for four upland cotton varieties (D&PL 5415, D&PL NuCotn 33B, D&PL 5816, and STV 474) at the Maricopa Agricultural Center. Four irrigation treatments based on MADL of 35% (Very Wet), 50% (Wet), 75% (Medium) and 90% (Dry) of available moisture were used to schedule irrigations after May 16. The Very Wet and Wet treatments showed statistically similar yields which were much greater than the Medium and Dry treatments. Irrigation return intervals of six to ten days from early June thru late July appeared to provide the greatest lint yields. Consumptive water use appears to reach its maximum during the peak bloom period of the fruiting cycle. Following peak bloom, water use gradually diminishes.
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Uddin, Md Nizam. "Effects of genetic variation in glaucousness, number of tillers and plant height on response to water stress in wheat." Thesis, The University of Sydney, 1986. https://hdl.handle.net/2123/28704.
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Studies were conducted to evaluate the effect of glaucousness,
number of tillers and plant height on response to water stress using
near-isogenic wheat lines under two water regimes. The effect of
glaucousness and number of tillers was studied under both field and
glasshouse conditions while that of plant height was studied only
under field conditions. In addition 28 wheat cultivars were evaluated
for epicuticular wax content and its relationship with spectral
reflectance.
Highly significant differences (1.51 to 2.8 mg/dm2) were found in
the amount of epicuticular wax (Ew) among the cultivars. Water
stress conditions promoted the development of Ew content significantly.
Ew content under control conditions and that under stress
conditions were positively correlated (r = 0.85, p <0.01) suggesting
that selection for this trait could be practised in either of the
environments. Surface reflectance was reduced when the waxy layer
from the leaf was removed with chloroform. The reduction for the
abaxial surface was twice that for the adaxial surface indicating that
the abaxial surface was more waxy than the adaxial one. The mean
reduction (both surfaces) termed '5' was positively correlated with
the amount of Ew (r = 0.59, p <0.01).
The effect of glaucousness was studied using six pairs of nearisogenic
lines (four pairs in case of glasshouse experiment). The
lines differed significantly in all the characters studied except one.
However, significant difference between the mean of glaucous and that
of non—glaucous lines was found only for epicuticular wax content and
water consumption per g of grain. 0n the average, glaucous lines
consumed 4.8% less water per g of grain under well-watered conditions
and 17.8% less under stress conditions than the non-glaucous lines.
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Nuruddin, Molla Md. "Effects of water stress on tomato at different growth stages." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33016.
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The study sought to identify the effects of deficit irrigation on the yield and quality of tomatoes. A greenhouse experiment was conducted during the summer of 1999 and repeated in winter 2000 using nine treatments. Two threshold soil moisture deficit levels, 65% and 80% depletion of plant available water, were factorially combined with 5 irrigation timing patterns: (i) no water stress (ii) stress throughout season, (iii) stress during flowering and fruit set, (iv) stress during fruit growth and (v) stress during fruit ripening. The treatments were set up in a randomized complete block design with 4 replicates. Crop yields, maximum and minimum equatorial diameter and fruit heights were measured. The quality parameters included: soluble solids, pH and the color index. Water stress throughout the growing season significantly reduced yield and fruit size but increased the level of soluble solids. No water stress throughout the growing season or stress only during the flowering stage provided highest tomato yield.
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Smit, Julie. "The effects of water availability on Impatiens capensis and Impatiens pallida (Balsaminaceae) /." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66125.
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Bellett-Travers, David Marcus. "Water relations and soil moisture requirements of transplanted amenity trees during establishment." Thesis, University of Hertfordshire, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251544.
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Staples, Mark Douglas. "Water consumption footprint and land requirements of alternative diesel and jet fuel." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81130.
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Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 101-110).
The Renewable Fuels Standard 2 (RFS2) is an important component of alternative transportation fuels policy in the United States (US). By mandating the production of alternative fuels, RFS2 attempts to address a number of imperfections in the transportation fuels market: US economic vulnerability to volatile prices; security and environmental externalities; and a lack of investment in alternatives to petroleum-derived fuels. Although RFS2 aims to reduce the climate impact of transportation fuels, the policy raises a number of additional environmental concerns, including the water and land resource requirements of alternative fuel production. These factors should be considered in order to determine the overall environmental viability of alternatives to petroleum-derived transportation fuels. Middle distillate (MD) fuels, including diesel and jet fuel, are of particular interest because they currently make up almost 30% of liquid fuel consumption in the US, and alternative MD fuels could potentially satisfy 21 of the 36 billion gallons of renewable fuels mandated by RFS2 in 2022. This thesis quantifies the lifecycle blue (surface and ground) water consumption footprint of MD from conventional crude oil; Fischer-Tropsch (FT) MD from natural gas and coal; fermentation and advanced fermentation (AF) MD from biomass; and hydroprocessed esters and fatty acids (HEFA) MD and biodiesel from oilseed crops, in the US. FT and rainfed biomass-derived MD have lifecycle blue water consumption footprints between 1.4 and 18.1 lwater/lMD, comparable to conventional MD, between 4.1 and 7.5 lwater/lMD. Irrigated biomass-derived MD has a lifecycle blue water consumption footprint potentially several orders of magnitude larger, between 2.5 and 5300 lwater/lMD. Results are geospatially disaggregated, and the trade-offs between blue water consumption footprint and areal MD productivity, between 490 and 3710 lMD/ha, are quantified under assumptions of rainfed and irrigated biomass cultivation.
by Mark Douglas Staples.
S.M.in Technology and Policy
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Ayuk, James. "Water regime requirements and possible climate change effects on Fynbos Biome Restionaceae." University of the Western Cape, 2018. http://hdl.handle.net/11394/6766.
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Philosophiae Doctor - PhDThe Cape Floristic Region (CFR) of southern Africa is one of the world’s most unique biodiversity hotspots. However, this biodiversity continues to be threatened by habitat loss due to rapid urbanisation, agriculture and alien vegetation encroachment, and now, by future groundwater extraction and climate change. Previous work had shown that soil moisture is important in structuring wetland plant communities at fine-scale. What is not fully known, however, is how the spatial distribution of species at a local scale is related to soil hydrology and what the response in the future of species distributions will be to perturbations arising from changes in climate or subsurface moisture in the future. The current research investigated the water regime of the Restionaceae which is a key family in the Fynbos biome and the implications of possible changes in soil hydrology caused by climate change in communities within this region. The Restionaceae were particularly appropriate because they are shallow rooted perennials with the ability to tolerate a wide range of water regimes which allows them to successfully co-habit within mixed plant communities as segregated clusters along fine-scale hydrologic gradients. Vegetation survey counts for the presence of these species along with measurements of soil water table depth and moisture content data generated from eight small-scale plots (50 x 50 m) were used to investigate the possible hydrological niches and to envision the potential impacts of a substantial reduction in rainfall and an increase in temperature as projected by Global Climate Models (GCMs) on the structure of Restionaceae communities in seasonal wetlands by 2100. A comparative analysis of the effects of two extreme Representative Concentration emission Pathways (RCP2.6 and RCP8.5) on significant hydrological variables to plant water regimes was carried out. The IPCC AR5 report describes the RCP8.5 emissions scenario as the likely ‘business as usual’ scenario where emissions continue to rise through the 21st century while the RCP2.6 scenario assumes that emissions peak between 2010 and 2020 and substantially subside thereafter.
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Copeland, Stephen Mark 1955. "Soil water potential as related to the Crop Water Stress Index of irrigated cotton." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276940.
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The application of the crop water stress index (CWSI) method to irrigation scheduling is enhanced by knowledge of the relationship between CWSI and soil water potential (SWP) and how this relationship is affected by soil texture. A study using the same cultivar of cotton on three different soils was conducted in southern Arizona over a single growing season. Detailed data were collected of CWSI and soil moisture content for several treatments that scheduled irrigations at threshold CWSI values. CWSI was correlated with soil water potential values calculated from pressure plate determined moisture release curves. Spatial variability of soil characteristics necessitated use of average rather than plot specific moisture release curves. Analysis showed a linear CWSI-SWP relationship that varied greatly with soil depth and study site. The study concluded that soil profile average SWP alone does not normalize the CWSI between sites with different soil textures.
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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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Neary, Daniel G., and John N. Rinne. "Baseflow Trends in the Upper Verde River Relative to Fish Habitat Requirements." Arizona-Nevada Academy of Science, 1997. http://hdl.handle.net/10150/296476.
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Gonzalez, Ruben Melendez 1954. "Nitrogen and mineral nutrition and water stress influence on vegetative growth of jojoba (Simmondsia chinensis (Link) Schneider)." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/191141.
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A survey of leaf mineral concentration of cultivated jojoba was conducted by selecting male and female plants of varying sizes. Mineral concentrations in jojoba were within the expected range for most cultivated plants. Nitrogen, P and Zn were higher in young leaves but K, Ca, Mg, Na and Mn were higher in old leaves. Iron and Cu were similar in old and young leaves. The order of jojoba leaf concentration was: N>K>Ca>Mg>Na>P and Fe>Mn>Zn>Cu. Soil macronutrients, Mn and Cu were adequate for jojoba growth but zinc and Fe were lower than accepted critical values for most crops. For a better understanding of jojoba mineral nutrition, a second experiment was conducted in greenhouse sand culture. Levels of 0, 4, 10, 50, and 100 ppm N in solution culture were evaluated on growth, N and P leaf concentration. Fifty ppm of solution N was adequate for optimum vegetative growth, shoot dry weight production and shoot N concentration (1.96 %) of jojoba plants. Nitrogen was higher in young (2.52%) than old leaves (1.52%) and increased with increments of N rates, as did shoot dry weight, shoot N and shoot P concentrations. Root dry weight did not change with N treatment levels but root N concentration increased with rate. Jojoba plants under field conditions are subjected to water stress and little information is available regarding the effect on leaf mineral concentration. Therefore, a greenhouse sand culture experiment was conducted to study irrigation fequencies of 3 min once every: 1) 2 hr for 10 hr/day, 2) day, 3) other day and 4) 4 days on growth of two clones and foliar, shoot and root N and P concentrations. Also, leaf water potentials were monitored. Vegetative growth increments were similar among treatments but treatment 3 resulted in statistically greater shoot and root dry weight. Leaf N concentration was similar among treatments but root N increased with greater moisture stress. Shoot P concentrations decreased with increasing water stress but root P did not show any pattern. The threshold leaf water potentials for jojoba growth cessation was in the range of -3.0 to -3.5 Mpa.
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Wong, Wai-yin Lawrence. "A review and comparison of the organic effluent discharge standards and requirements of Hong Kong and other countries /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1745766X.
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Yagi, Kazuhiko 1957. "Near real-time irrigation scheduling using the Bowen ratio technique." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277106.
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The actual evapotranspiration rate for wheat at the Campus Agriculture Center (CAC) and alfalfa at the Maricopa Agricultural Center (MAC) were measured using the Bowen ratio technique for near real-time irrigation scheduling. The Bowen ratio method underestimated evapotranspiration when compared with AZMET and Penman data. There were problems with the hygrometer and the net radiometer which might have caused this underestimation. The height-fetch ratio requirement was not met, and this may have affected the data. Irrigation scheduling programs and the technique to schedule irrigation in a near real-time were developed. Irrigation programs were not field tested because of the problem with field data. Simulated data was successfully used to demonstrate its application. It was found that irrigation could be scheduled in a near real-time with the programs provided reliable data and proper data acquisition systems are used.
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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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Yang, Dongsheng. "The response of two eucalypt subspecies to water stress and fertilizer at early seedling stage." Thesis, Canberra, ACT : The Australian National University, 1987. http://hdl.handle.net/1885/140223.
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Chirwa, M. P. W. "An evaluation of the minimum requirements for the design of rural water supply projects." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/2895.
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Thesis (MScEng (Civil engineering))--University of Stellenbosch, 2005.In this study, the minimum standards required for the design of rural piped water supply projects as set by the Department of Water Affairs and Forestry (DWAF) are evaluated with respect to capital pipe cost using the Nooightgedacht rural water supply scheme selected as a case study.
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Hachigonta, Sepo Promise. "Assessing maize water requirements in the context of climate change uncertainties over southern Africa." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/10604.
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Climate change studies are subject to high uncertainties partly resulting from data reliability. This study investigates the challenges of using statistical downscaled climate data to examine the likely impacts of climate change on maize growth in southern Africa in the context of these uncertainties.
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Lebeau, Benoit. "Les tensiometres pour l'irrigation en milieu tourbeaux." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22754.
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Water management for the irrigation of containerized production remains a task reserved to a highly qualified personnel. Without proper instruments to determine the actual water needs, nursery crops can face growth losses of 20 to 30%.Reviewing the different methods that are used in field production, tensiometer have shown the greatest potential of adaptation to potted plants.
Tests on the utilization of tensiometer were realized on two peat-vermiculite substrates, using two types of porous cup (1 bat--standard flow and 1 bar--high flow). The instruments were tested while permanently fixed in the growing medium, and temporarily fixed for three hours in the growing medium.
The results show that the instruments give excellent measurements for normal condition of growth, requiring saturation level between 50 and 100%, and that for both mode of operation.
Preferably, the choice of the instrument should be based on the hydraulic characteristics of the substrate. Little difference has been found using both instrument in the substrate 1, but in substrate 2 however, the high flow porous cups have given better response. The high flow cups have higher porosity and bigger pores that suit better substrate 2, which is made of coarser particles.
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Bisso, Eya Joseph 1955. "The effects of maturity differences on competition between adjacent rows of Sorghum bicolor varieties at two levels of soil moisture." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276972.
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The objective of the study was to determine if and how grain sorghum hybrids (Sorghum bicolor (L.) Moench) of different maturity dates compete with one another when planted in adjacent rows under different moisture levels. Five sorghum varieties differing in their maturity were used: Taylor Evans Y-101-G coming to mid-bloom in 71 days, RS 610, Asgrow Corral, DK 64 and DK 69 coming to mid-bloom in 56.9 days, 61 days, 69.3 days and 75.6 days respectively. Six agronomic characters were measured to determine the effect and extent of competition. They included the number of days to mid-bloom, tiller ratio, grain yield, grain test weight and 300-seed weight. According to the results, adjacent row competition took place due to differences in maturity date for grain yield and 300-seed weight. An almost equilibrium appeared between loss or gain of border rows compared to the loss or gain of the middle row. Also the length of time between day to mid-bloom of the border rows hybrids and the center row genotype was important in the extent of competition effects.
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Refay, Yahya Ali. "The influence of variable amounts of irrigation water and nitrogen fertilizer and their interaction on the development, growth and nitrogen uptake of grain orghum." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184677.
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The influence of variable amounts of irrigation water and nitrogen fertilizer and their interaction on the development, growth, grain yield and nitrogen uptake of grain sorghum were studied under monocrop (May 21 planting) and simulated double crop (July 1 planting) in the 1985 growing season and under monocrop in the 1986 growing season. Six grain sorghum hybrids, three of which had a higher grain yielding ability and the other three with a lower grain in yielding ability, were used in this study conducted at the University of Arizona, Marana Agricultural Center. All six hybrids were grown under two planting dates (May 21, July 1), two levels of irrigation water (dry, wet), and two levels of nitrogen fertilizer (0, 112 kg N/ha) in the 1985 growing season. In the 1986 growing season, two hybrids were grown under three levels of irrigation water (dry, medium, and wet) and three levels of nitrogen fertilizer (0, 84, 168 kg N/ha). Planting on May 21 (monocrop) had more days to 50% bloom, leaf area, heads number, grain yield and total dry weight than the July 1 planting (double crop). However, planting on July 1 produced a longer head exsertion (peduncle length) compared to May 21 planting. Head length, plant height, 500 seed weight, and grain volume-weight were not affected by planting date. Water stress reduced head exsertion, head length, plant height, head number, 500 seed weight, grain yield and total dry matter. However, numbers of days to 50% bloom were increased by dry treatment. Leaf area and grain volume-weight were not significantly affected by water levels. Under the conditions of this study, nitrogen fertilizer rates did not produce an effect on most of the agronomic characteristics of grain sorghum hybrids studied in this experiment. However, increased nitrogen fertilizer rates increased the uptake and nitrogen concentration in all growth stages of hybrids in the 1986 growing season.
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Tewolde, Haile. "Seasonal gas exchange rates and growth of pearl millet (Pennisetum americanum (L.) Leeke); across a gradient of drought." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184684.
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Seasonal patterns of stomatal activity, plant-temperature-based drought stress indices, growth and grain yield of two pearl millet (Pennisetum americanum (L.) Leeke) parental lines and their F₁ hybrid were studied under a sprinkler irrigation gradient system in 1985 and 1986 in Tucson, Arizona. Physiological and morphological measurements of stressed and nonstressed plants were made periodically starting at the panicle initiation stage. Well-defined trends in stomatal conductance (Cg), transpiration (Tr), and photosynthetic (Pn) rates of nonstressed plants were observed over the seasons. Tr increased from 5ug H₂O cm⁻²s⁻¹ at early panicle development stage to a peak of up to 30 ug cm⁻²s⁻¹ at flowering and declined to 10 ug cm⁻²s⁻¹ at maturity. Pn of well-irrigated plants was highest (26 uMoles CO₂ m⁻²s⁻¹) at early flag leaf appearance stage and declined slowly to 14 uMoles m⁻²s⁻¹ at maturity. In extremely stressed plants, Cg, Tr and Pn were highest early in the seasons, lowest in the middle of the seasons, and slightly increased towards the end of the seasons. The seasonal trends in stomatal response depended on the stage of plant growth and vapor pressure deficit of the air. Transpiration efficiency was highest at partial stomatal closure. Morphologically, the F₁ hybrid was more like its male than its female parent. The female parent produced less dry matter, had thinner leaves and greater ratio of leaf to stem dry matter, and yielded less grain than the other genotypes. The results indicated that leaf:stem ratio can be a useful selection criterion of drought avoiding genotypes. Plants that develop stems and heads rapidly (low leaf:stem ratio) are more desirable under stress than plants that tend to become leafy. Decreases in Tr, Pn, dry matter and grain yield due to stress could be assessed with canopy or leaf temperature, canopy minus air or leaf minus air temperature, and crop (CWSI) or leaf (LWSI) water stress indices. CWSI and LWSI were more desirable in assessing stress than the other indices. CWSI is effective in assessing the magnitude of stress in a crop stand, while LWSI may be useful in situations where use of the infrared thermometer is difficult.
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Kokwe, Misael 1960. "Growth and yield of two sorghum hybrids (Sorghum bicolor (L.) Moench) under a limited supply of soil moisture imposed at different stages of growth." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276797.
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This study evaluated relative responses of two grain sorghum (Sorghum bicolor (L.) Moench) hybrids to moisture stress treatments imposed during the seedling, early boot, flowering and grain-filling stages. The two hybrids, T.E. Y77 and FUNK HW6125, are high and low yielding respectively, having similar maturity periods. Twelve phenological characters were measured. The height to upper leaf collar, peduncle exsertion, panicle length, total plant height and total leaf area showed significant differences between the hybrids. Early boot stage stress was most sensitive to vegetative characters. T.E. Y77 produced more heads/m², grains, panicle, 500 grain weight (seed size), and grain yield/ha than FUNK HW 6125 across all treatments. Seed size was the most important determinant of grain yield in both hybrids. Moisture stress during the seedling and early boot stages enhanced grain yield, whereas during the grain-filling stage it was detrimental to grain yield in both hybrids.
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Sarvestani, Zeinolabedin Tahmasebi. "Water stress and remobilization of dry matter and nitrogen in wheat and barley genotypes /." Title page, table of contents and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phs251.pdf.
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Trenholm, Leif. "Effects of water table depths and fertilizer treatments on yield and quality of tomatoes." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22818.
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A field lysimeter experiment was conducted during 1993 and 1994 using 4 water table depths (WTD) (0.3, 0.6, 0.8, and 1.0 m), 13 treatment levels of calcium (0, 1500, and 2500 kg/ha) and potassium (0, 160, and 400 kg/ha), to determine their effects on tomato quality and yield. Plant parameters measured included: yield (fruit/plant), fruit height, maximum and minimum equatorial width, degree of catfacing (scale of 1 to 5), and sunscald (scale of 0 to 2).Water table treatment was usually highly significant for the parameters measured at harvest. Largest height, equatorial width and yield of tomato fruit occur with 0.6 to 0.8 m WTD. Fertilizer treatments were rarely significant by WTD, but if they were, they tended to be in the 0.3 or 1.0 m WTD. Maintaining a WTD of 0.6 to 0.8 m and fertilizing with 160 kg/ha of K can improve quality and total yield of tomatoes.
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Fuller, Zoe. "Photoperiodic entrainment of seasonally adaptive metabolic changes, the doubly-labelled water technique for estimating energy requirements and the role of pelage in the regulation of energy." Thesis, Liverpool John Moores University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310121.
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Doerge, Thomas, Tim Knowles, Mike Ottman, and Lee Clark. "Predicting the Nitrogen Requirements of Irrigated Durum Wheat in Graham County Using Soil and Nitrate Analysis." College of Agriculture, University of Arizona (Tucson, AZ), 1987. http://hdl.handle.net/10150/203767.
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The high yielding spring wheats grown in Arizona usually require applications of fertilizer nitrogen (N) to achieve optimum grain yields and acceptable quality. The University of Arizona's currently recommended procedure (preplant soil plus periodic stem tissue analysis for NO₃-N to predict the N needs of wheat) is not widely used by Graham County growers for various reasons. A nitrogen fertility trial was conducted at the Safford Agricultural Center during the 1986-87 crop year to: 1) examine the relationships between basal stem nitrate-N levels, grain yields of durum wheat, and N fertilizer rates; and 2) to test the accuracy of the recommended procedure for predicting the N needs of durum wheat. Five rates of N from O to 419 lbs N /acre were applied in three split applications. One additional N treatment was made as indicated by the current University of Arizona procedure. Maximum grain yields of 5500 to 6200 lbs /a and protein levels in excess of 14.5% were attained with the application of at least 186 lbs NIA. An untimely early season irrigation induced a temporary N deficiency condition for all plots, which may have kept grain yields below the maximum yield possibility for this site. In spite of this, the amount of N predicted by the University of Arizona procedure (197 lbsN/acre) did attain an adjusted economic return which was not significantly different from the maximum numerical yield that was achieved for any of the other N treatments.
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Peter, Craig Ingram. "Water requirements and distribution of Ammophila arenaria and Scaevola plumieri on South African coastal dunes." Thesis, Rhodes University, 2000. http://eprints.ru.ac.za/38/.
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Feldman, William R., Steven A. Carter, and Kim W. Stone. "Water Requirements of Arid-adapted Groundcover and Sub-shrub Species for Landscape Use in Arizona." University of Arizona (Tucson, AZ), 1997. http://hdl.handle.net/10150/554260.
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Norrish, Shane A., University of Western Sydney, of Science Technology and Environment College, and School of Environment and Agriculture. "Soil and water interactions controlling wheat crop response to phosphorus fertiliser in north-western New South Wales." THESIS_CSTE_EAG_Norrish_S.xml, 2003. http://handle.uws.edu.au:8081/1959.7/613.
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This thesis examines the response to P fertiliser by wheat crops growing in the vertosol soils of the low rainfall areas of the northern grain zone of eastern Australia. Farmers in this region depend on water accumulated from rainfall over a fallow period and stored in the subsoil to increase wheat grain yield beyond that normally achievable from in-crop rainfall and to decrease the production risks due to rainfall variability. The large variability in stored water, seasonal rainfall and subsoil properties result in extremely varied yield and yield responses to P fertiliser between seasons and between sites. Finally, as a practical guide to predicting wheat response to P fertilizer: 1/. current sampling strategies of determining P only in the surface 10 cm appear to be adequate for soils with bicarbonate P concentrations greater than 15 mg/kg. 2/. For soils with lower concentrations in the surface, sampling of 80 cm is recommended. Crops with a mean concentration of bicarbonate P greater than 7 mg/kg between 10 - 80 cm are unlikely to respond to P fertiliser. 3/. No increase in profitable grain yield response was found for fertiliser applications greater than 10 kg P/ha.Doctor of Philosophy (PhD)