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1
Solum, James R. "Estimating Evapotranspiration of a Riparian Forest Using Sap Flow Measurements." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2170.
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To close the water use budget of irrigated agricultural fields in floodplains with substantial riparian corridors, it is necessary to understand groundwater usage by dominant phreatophytic vegetation, particularly when the primary source of water for irrigation comes from groundwater abstraction. We report here results of estimated evapotranspiration (ET) of a riparian forest, which were based on measurements of sap flow in phreatophytic vegetation within a riparian corridor. The riparian corridor was within a study area 75 to 140 meters wide in the lower portion of the Scotts Creek watershed, which is bounded to the west by the Pacific Ocean in Santa Cruz County, California. Canopy coverage in the study area often approaches 100% during the growing season, with dominant trees being red alder (Alnus rubra Bong.), arroyo willow (Salix lasiolepis Benth.), and pacific willow (Salix lasiandra Benth. var. lasiandra). Other trees include boxelder (Acer negundo L.), bigleaf maple (Acer macrophyllum Pursh.), California bay laurel (Umbellularia californica (Hook. & Arn.) Nutt.), and coastal redwoods (Sequoia sempervirens (D. Don) Endl.). Common understory vegetation includes California blackberry (Rubus ursinus Cham. and Schlecht.), stinging nettle (Urtica dioica subsp. gracilis L.), poison hemlock (Conium maculatum L.), Cape ivy (Delairea odorata Lem.), Italian thistle (Carduus pycnocephalus L. subsp. pycnocephalus), and western poison oak (Toxicodendron diversilobum (Torr. & A. Gray) Greene). We hypothesized that the ET of a riparian forest could be estimated by measuring the sap flow of riparian phreatophytic trees. For the study reported here, only the two most dominant phreatophytic species, namely red alders and arroyo willows, were instrumented with thermal dissipation probes. In addition to diurnal fluctuations, sap flow data collected hitherto also showed expected seasonal variation with summer maxima and winter minima, with transition fall and spring periods. Sap flow measurements from the study area were used to estimate riparian forest ET by projecting them across the canopy areal extent of the riparian forest using sampled tree sapwood areas from six sample plots. The sap flow-based ET results were then compared to ET results reported by two other methods. Additional research, including increased number of trees with thermal dissipation probes, further analysis of sap flow behavior, and continued long-term measurement of sap flow, is needed to further improve the method of using long-term sap flow measurements to estimate the ET of a riparian forest.
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Chavarro-Rincón, Diana. "Tree transpiration mapping from upscaled sap flow in the Botswana Kalahari." Enschede : University of Twente [Host], 2009. http://doc.utwente.nl/60696.
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Sevanto, Sanna. "Tree stem diameter change measurements and sap flow in Scots pine." Helsinki : University of Helsinki, 2003. http://ethesis.helsinki.fi/julkaisut/mat/fysik/vk/sevanto/.
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Sam, Mpaballeng Catherine. "Calibration of sap flow techniques in citrus using the stem perfusion method." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60855.
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The aim of this study was to calibrate and decide on the most appropriate sap flow technique for citrus species in the laboratory by pushing water through cut branches. Various sap flux density techniques, including heat pulse techniques (heat ratio and compensation heat pulse methods) and the heat dissipation technique were calibrated in four citrus species, namely Citrus sinensis (Oranges), Citrus reticulata (Soft citrus), Citrus paradise (Grapefruit) and Citrus limon (Lemons). Sap flux density, determined by these three techniques, was compared to that determined gravimetrically, which was calculated as the rate of change in the mass of water passing through the stem segment divided by the area of conducting wood. Results showed that the sap flux density was consistently underestimated by all techniques and across all citrus species/varieties. However, fairly good correlations (R2>0.7) between sap flux densities determined by a sap flow technique and gravimetric determinations were found for all techniques in some stems. Despite the good correlations found in the study, a single calibration factor for each technique could not be found for citrus using the stem perfusion method. Calibration factors were determined as the inverse of the slope of the linear relationship between sap flux density determined with a sap flow technique and that determined gravimetrically. These correction factors varied between citrus species and even within stems of the same species.
Vessel dimensions (lumen diameter) and distance between groups of xylem vessels in citrus species was determined in order to try and explain the underestimation of sap flux density and the large variations in the calibration factors obtained during the calibration of the various sap flow techniques. The results revealed that the variation and underestimation were caused by contact of the probes with inactive xylem and due to differences in the nature of sapwood. The xylem vessels were unevenly distributed throughout the sapwood with large distance between the vessels, meaning that the sapwood of the studied species was considered inhomogeneous and therefore departed from the idealised theory of heat pulse measurements. The theory needs to be adapted to account for such sapwood and because of the large variation in the sapwood properties between different citrus species, calibration of these techniques is probably necessary for each new species and orchard in which measurements are to be made. Our analysis of the performance of sap flow techniques showed that the HR method should perhaps be considered before the CHP and TD methods.Dissertation (MSc (Agric))--University of Pretoria, 2016.
Plant Production and Soil Science
MSc (Agric)
Unrestricted
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Folkerts, Shaun Hajo 1972. "Water use by Emory oak in southeastern Arizona: Estimation by sap-flow measurements." Thesis, The University of Arizona, 1999. http://hdl.handle.net/10150/278683.
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Water use by mature and sprout (coppice) forms of Emory oak (Quercus emoryi) was estimated by the sap-flow method. Five standards and five coppice trees were sampled in an area that had been harvested for fuelwood and five mature trees were sampled in an uncut area. Differences were recognized between coppice and standards in the cut area and between coppice trees and mature trees from the uncut area. Regression equations were derived relating estimated annual water use to tree diameter, height, and crown measurements for both cut- and uncut-area trees. Seasonal water use by each tree form showed relationship to precipitation, but little relationship to temperature and relative humidity. Woodland density and tree size measurements facilitate extrapolation of water use from the 15 sampled trees to a per area basis. Water use was approximately 1900 cubic meters per hectare per year, based upon drc measurements, for the uncut area and 3168 cubic meters for the cut area. Estimated water use on a per unit area was approximately 1.67 times greater for the cut area than the uncut area.
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O'Keefe, Kimberly. "Patterns and ecological consequences of water uptake, redistribution, and loss in tallgrass prairie." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/34514.
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Doctor of PhilosophyDivision of Biology
Jesse B. Nippert
Water availability is a key driver of many plant and ecosystem processes in tallgrass prairies, yet we have a limited understanding of how grassland plants utilize water through space and time. Considering that tallgrass prairies experience tremendous heterogeneity in soil resources, identifying spatiotemporal variation in plant ecohydrology is critical for understanding current drivers of plant responses to water and for predicting ecosystem responses to future changes in climate. Here, I investigated the patterns, drivers, and ecological consequences of plant water use (e.g., water uptake, water redistribution, and water loss) in a native tallgrass prairie located in northeastern Kansas, USA. Using a combination of leaf gas exchange, sap flow, and isotopic techniques, I addressed four main questions: 1) How does fire and grazing by bison impact use of water from different sources and niche overlap for common grasses, forbs, and shrubs? 2) Does hydraulic lift occur in grazed and ungrazed tallgrass prairie, and does this impact facilitation for water within grassland communities? 3) What are the patterns and drivers of nocturnal transpiration in common grassland species? 4) How does diel stem sap flow and canopy transpiration vary among common grassland species? I found that bison grazing increased the depth of water uptake by Andropogon gerardii and Rhus glabra, reducing niche overlap with co-occurring species. Conversely, grazing did not affect hydraulic lift, which was generally uncommon and likely limited by nocturnal transpiration. Further, leaf gas exchange measurements indicated that nocturnal transpiration occurred commonly in tallgrass prairie plants and was greatest among grasses and early in the growing season. Nocturnal transpiration was not driven by vapor pressure deficit or soil moisture, as commonly observed in other systems, but was regulated by nocturnal stomatal conductance in most species. Finally, I found that daytime sap flow rates were variable among species and functional types, with larger flux rates among woody species. Nocturnal sap flow rates were more consistent across species, which caused nighttime sap flow and transpiration to account for a larger proportion of daily flux rates in grasses than in forbs or shrubs. These results show that water uptake, water redistribution, and water loss are all influenced by different biotic and abiotic drivers and have varying ecological impacts across a heterogeneous landscape. Additionally, extensive differences in water flux exist among co-occurring species and plant functional groups, which likely reflect varying strategies to tolerate water limitation. These results suggest that shifts in the abundance of these species with future climate changes, or with ecosystem state changes, will likely impact ecosystem-level water balance.
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Renz, Jennifer Theresa. "Assessing evapotranspiration rates of a Mid-Atlantic red maple riparian wetland using sap flow sensors." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2400.
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Thesis (M.S.) -- University of Maryland, College Park, 2005.Thesis research directed by: Dept. of Natural Resource Sciences and Landscape Architecture. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Carvalho, Tomás Viana. "A importância da monitorização do clima, solo e planta para a gestão da rega na vinha (Vitis vinifera L.)." Master's thesis, ISA/UL, 2015. http://hdl.handle.net/10400.5/11211.
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Mestrado em Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências - Universidade do PortoThe following thesis is included in the European project Innovine (granted agreement nº FT7-311775), which include the collaboration of several institutions with a long range of scientific areas, with the purpose of presenting results of an essay in an Alentejo sub-region – Reguengos. In this essay several sensors were installed for the use of phytomonitorization as a tool to monitor two types of deficit irrigation, RDI – Regulated Deficit Irrigation; SDI – Sustainable Deficit Irrigation. This phytomonitorization will be important in order to understand some determining physiological parameters of a vineyard in response to water stress, using the variety “Touriga Nacional”. For both types of deficit irrigation a representative grapevine was selected, on which the following phytomonitoring sensors were installed - sap flow, leaf and berry temperature and trunk diameter, canopy humidity). Leaf temperatures ranged from 6,1ºC to 48,7ºC in RDI and from 9,2ºC to 47,3ºC in SDI. For the berry temperatures the temperature ranged from 6,1ºC to 49ºC in both modalities. As possible estimators for physiological parameters, when analyzing a single irrigation period, we obtained high determination coefficients for the leaf temperature (R2=0,90 and R2=0,76) when related with the ψb. As possible estimators of ψfd parameters we obtained high determination coefficients for air temperature (R2=0,0,81 and R2=0,78). For the sap flow the determination coefficients were R2=0,63 and R2=0,60 after irrigation and R2=0,80 and R2=0,76 before irrigation. Also for the leaf temperature vs leaf water potential we obtained R2=0,67 and R2=0,67 after irrigation and R2=0,52 and R2=0,59 before irrigation
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Witmer, Robert K. "Water Use of Landscape Trees During Pot-In-Pot Production and During Establishment in the Landscape." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/30199.
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Water conservation and pollution concerns from nutrient runoff will very likely dictate precise irrigation regimes for nursery managers in Virginia. Maximum plant growth with minimum input of water and fertilizer is becoming increasingly important. Therefore, water use and growth of red and sugar maple (Acer rubrum L. 'Franksred' and Acer saccharum Marsh.) were studied during two years of pot-in-pot (P+P) production and during three years after transplanting to field soil. Three major experiments were completed. The first experiment studied the effect of frequent irrigation (three-times-a-day) versus standard once-a-day irrigation and found that frequent irrigation increased trunk diameter growth of sugar maples in the second production cycle and for red maples in both production cycles. Height growth of neither species was affected by frequent irrigation. A study of sap flow pattern indicated that late day water stress of red maples was partially alleviated by frequent irrigation. In the second experiment, red and sugar maples were transplanted to field soil after one (1-yr) or two (2-yr) years of P+P production. Irrigation frequency requirement decreased as the trees grew and depended on environmental conditions, size at planting, source of water (rainfall versus irrigation) and species. Height and trunk diameter of 1-yr red maple was equal to that of 2-yr trees after only one year. Height and trunk diameter differences between 1-yr and 2-yr sugar maple trees persisted three years after transplanting. In the third experiment water use of 1-yr and 2-yr red and sugar maple while in P+P production was investigated. Four models of daily water-use were developed. A simple model that is suitable for growers includes species, trunk cross-sectional area (BA) and air temperature (TA) observations. An environmental model was developed using the Penman-van Bavel estimate of evapotranspiration (ET). ET required modifications based on tree characteristics, air temperature, windspeed and relative humidity to be an effective predictor of water-use. A complex model was based on a sine-cosine function of day-of-the-year. This model fits water-use data well for each species and production cycle and includes BA, ET and TA. An alternate simpler model requires only day-of-the-year, TA and BA, offering growers a relatively simple and accurate model of water use.Ph. D.
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Gebauer, Tobias. "Water turnover in species-rich and species-poor deciduous forests xylem sap flow and canopy transpiration /." Göttingen : Georg-August-Universität, 2010. http://webdoc.sub.gwdg.de/diss/2010/gebauer/gebauer.pdf.
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McGuire, Roberta Delehanty. "Transpiration, Growth And Survival Of Native Riparian And Introduced Saltcedar Trees In Mixed Stands On The San Pedro River, U.S.A." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/556824.
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Western riparian zones have undergone significant landscape changes over the past several decades, with introduced saltcedar (Tamarix spp.) as a crucial component of this transformation. Saltcedar, now a dominating presence along many western rivers, due to its high tolerance to drought, salinity and stress, is considered to be a high-water-use plant that can desiccate disturbed river systems. Where native and saltcedar plant communities occur together, it is important to understand water use patterns and the physiological responses of each species to environmental stress factors, as a way to project an eventual course of succession processes and management options at a given site. Stress and disturbance in the form of reduced stream flows and land use changes may influence these interactions. Understanding the conditions that allow for saltcedar dominance is critical in determining riparian water budgets, and developing effective management strategies. Sap flux sensors were used to measure the physiological response of co-occurring communities of saltcedar and native trees to these environmental stress factors during the pre-monsoon period in early summer, a time of maximum stress for riparian vegetation. The results suggest that native trees are still competitive with salt cedar so that a mixed plant community is likely to continue on the San Pedro River on the condition that current groundwater levels and river flows are maintained. If base flows and depth to groundwater continue to decline, this competitive balance between saltcedar and native trees likely could change.
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Aumann, Craig Alvan. "Development, parameterization and numerical solution of an unsaturated flow model for water in the sapwood of a Douglas-fir tree /." Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/6374.
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Lundstrom, Dylan. "Effects of vineyard deficit irrigation on berry composition and yield during 2014 California drought." Master's thesis, ISA, 2017. http://hdl.handle.net/10400.5/15839.
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Mestrado Vinifera Euromaster - Instituto Superior de Agronomia - ULThe effect of deficit irrigation on berry composition, berry weight and yield was studied across 5 vineyards located in two regions exhibiting Mediterranean climate in California. The study used sap flow and pre-dawn leaf water potential (PDWP) to monitor the water status of the vines and trigger irrigation opportunities. Vineyard blocks were “split” and two irrigation regimens were imposed: traditional and experimental. Traditional treatment for each vineyard continued conventional methodologies used by growers at each site. Experimental sites used sap flow as the primary indication of irrigation timing while PDWP was used to confirm sap flow data. Fruit composition was monitored starting at veraison through to harvest, monitoring primary metabolites at all sites and secondary metabolites at participating sites. Variables monitored included: water applied, berry weight, tannin, total anthocyanins, yield, water deficit index, sugar concentration, pH and titratable acidity. Data from all sites was combined and correlations between all variables were determined. A regression analysis was also used to analyze the effects of the amount of water applied and water deficit index on yield components and berry composition. Simple data analysis shows the differences between water input in the traditional and experimental sites (30 – 100% water savings). Study outcomes were largely inconclusive and despite the strong correlations obtained between variables, they were often inconsistent with literature. Berry weight was found to have a moderately negative correlation with the amount of water applied and water deficit index. Tannin content was also found to have a negative relationship with the amount of water applied. Brix was found to be positively correlated with water applied and water deficit index. These inconsistent results may be due to factors such as different varieties, sites and management techniques being used across different producers. The absence of statistically robust results prevent us from drawing conclusions. Additional research is suggested to confirm this results in order to evaluate the viability of using the sap flow technique to manage deficit irrigation
N/A
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Gebauer, Tobias [Verfasser]. "Water turnover in species-rich and species-poor deciduous forests : xylem sap flow and canopy transpiration / Tobias Gebauer." Göttingen : Georg-August-Univ, 2010. http://d-nb.info/1004465939/34.
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Helfter, Carole. "Non-invasive measurements of phloem and xylem sap flow in woody plants by a laser-based heat pulse technique." Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/2172.
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The ambition of the work presented in this thesis is to address the need for nondestructive, repeatable measurements of long-distance transport of photosynthates through the phloem vascular tissue of woody plants. Quantification of long-distance phloem transport is believed to be able to provide information relevant to the forest carbon cycle as well as to a plant's response to changes in its environment. However, due to the fragility of the tissue, invasive techniques such as used routinely for the monitoring of water flow through the xylem are not applicable. Consequently, very little field data on phloem transport rates and patterns are currently available.
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Rakonczay, Zoltán. "Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30624.
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Carbon dioxide efflux rates (CER) of stems and roots of overstory and understory black cherry (Prunus serotina Ehrh., BC), red maple (Acer rubrum L., RM) and northern red oak (Quercus rubra L., RO) trees were monitored over two growing seasons at two contrasting sites in the Great Smoky Mountains to investigate diurnal and seasonal patterns in respiration and to develop prediction models based on environmental and plant parameters.
CER of small roots (d<0-8 mm) was measured with a newly developed system which allows periodic in situ measurements by using permanently installed flexible cuvettes. Temperature-adjusted CER of roots showed no diel variation. The moderate long-term changes occurred simultaneously in all species and size classes, suggesting that they were driven mostly by environmental factors. Mean root CER ranged from 0.5 to 4.0 nmol g⁻¹ d.w. s⁻¹. Rates were up to six times higher for fine roots (d<2.0 mm) than for coarse roots.
CER (per unit length) of boles (d>10 cm) and twigs (d<2 cm) was related to diameter by the function lnCER = a+D·lnd, with D between 1.2 and 1.8. A new, scale-invariant measure of CER, based on D, facilitated comparisons across diameters. Q₁₀ varied with the method of determination, and it was higher in spring (1.8-2.5) than in autumn (1.4-1.5) for all species. Daytime bole CER often fell below temperature-based predictions, likely due to transpiration. The reduction (usually <10%) was less pronounced at the drier site. Twig CER showed more substantial (often >±50%) deviations from the predictions. Deviations were higher in the canopy than in the understory. Mean bole maintenance respiration (at 20°C and d=20 cm) was 0.66, 0.43 and 0.50 μMol m⁻¹, while the volume-based growth coefficient was around 5, 6 and 8 mol cm⁻³ for BC, RM and RO, respectively.
In a controlled study, BC and RM seedlings were fumigated in open-top chambers with sub-ambient, ambient and twice-ambient levels of ozone. The twice-ambient treatment reduced stem CER in BC by 50% (p=0.05) in July, but there was no treatment effect in September or in RM. Ozone reduced root/shoot ratio and diameter growth in BC, and Pmax in both species.Ph. D.
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Holmes, Christopher Dale. "Effects of three global climate change factors on soil water and sap flow of Larrea tridentata in the Mojave Desert." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1464439.
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Pearlstein, Susanna Lee. "Methods for Measuring Tamarisk (Tamarix spp.) Water Use on Two Sub-Watersheds in The Western United States as Impacted by The Tamarisk Leaf Beetle (Diorhabda spp.)." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/594631.
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The Dolores River in Utah and the Virgin River in Nevada are ecosystems under pressure from increased groundwater withdrawal due to growing human populations, climate change and introduced species such as Tamarix spp. (tamarisk). Tamarisk is reputed to take excessive water from its environment. Controlling tamarisk is of concern in the western United States where plants grow quickly in already fragile and diminishing riparian areas. For this reason, biologic control beetles Chrysomelidae: Diorhabda carinulata were released to weaken the tamarisk population, thus reducing its water use. The studies for this dissertation were conducted between 2010 and 2011. We quantified tamarisk water use over multiple cycles of annual defoliation using sap flow measurements, leaf area index (LAI), well data, allometry and satellite imagery from EOS-1 Moderate Resolution Imaging Spectrometer (MODIS) sensor. Study objectives for the Virgin River were to measure evapotranspiration (ET) before beetles ever arrived and to examine the effects on tamarisk ET in the year after beetle arrival. This site showed plant ET from sap flow averaged about 4.3 mm m⁻² leaf day⁻¹ in 2010. In 2011, ET from sap flow averaged 6.4 mm m⁻² leaf area day⁻¹ pre beetle arrival, but dropped to 3-4 mm m⁻² leaf area day⁻¹ after beetle arrival. Stand level ET measured by MODIS was 2.2 mm d⁻¹ in 2010 and approximately 1.5 mm day⁻¹ when beetle arrival was measured in 2011. Significant visual change was apparent as the trees senesced. Results showed the first year of beetle arrival resulted in reduced ET but did not result in significant water savings. We also compared the reaction of the newly defoliated (in 2011) Virgin River site to the long-term defoliated (since 2007) Dolores River site to explore if all beetle invasions were created equal. This paper views the two sites as fairly extreme examples of tamarisk stand reaction to the beetle. While no mortality was reported at the Dolores River site, the site is much older, less photosynthetically active and covers far less ground when compared to the younger tamarisk monoculture on the Virgin River. Pre-beetle arrival Normalized Difference Vegetation Index (NDVI) values were higher on the Virgin River than on the Dolores River. Beetle arrival at each site was captured with Landsat NDVI and a reduced NDVI signal (13% drop in NDVI at Dolores River, 5% drop at Virgin River) was seen after beetle arrival.
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Bunnell, Michael Cameron. "Water Use of Four Commonly Planted Landscape Tree Species in a Semi-Arid Suburban Environment." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6146.
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Native plant communities and agricultural land are commonly converted to urban areas as cities across the Western United States continue to grow and expand. This expansion is typically accompanied by afforestation where a common goal among communities is to maximize shade tree composition. Planted forests in these regions are commonly composed of introduced tree species native to mesic environments and their ability to persist is dependent on consistent irrigation inputs. Many potential ecosystem services may be derived from planting trees in urban and suburban areas; however, there are also costs associated with extensive afforestation, and shade tree cover may have significant implications on municipal water budgets. In this study I evaluate variation in daily and seasonal water use of regionally common suburban landscape tree species in the Heber Valley (Wasatch County, Utah). I had two primary objectives: (1) to identify and understand the differences in transpiration between landscape tree species in a suburban setting and (2) to assess the sensitivity of sap flux and transpiration to variation in vapor pressure deficit, wind speed, and incoming shortwave radiation. I used Granier's thermal dissipation method to measure the temperature difference (ΔT) between two sap flux probes. The empirical equation developed by Granier was used to convert ΔT into sap flux density (Jo) measurements, which were then scaled to whole-tree transpiration. There were consistent and substantial differences in sap flux between tree species. I found that Picea pungens under irrigated growing conditions, on average, had Jo rates that were 32% greater and whole tree water use (ET) rates that were 550% greater than all other species studied. The findings of Jo may be partially explained by xylem architecture and physiological control over stomatal aperture. However, the rate of water flux in the outermost portion of sapwood does not necessarily determine the magnitude of whole tree transpiration. Rather, ET in this study was largely explained by the combined effects of irrigation, tree size, and sapwood to heartwood ratio.
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Amaravathi, Kiran Kumar. "The role of crack willow in the wetland water balance, Moutere region, New Zealand." Thesis, University of Canterbury. School of Forestry, 2010. http://hdl.handle.net/10092/5753.
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The Waiwhero wetland (16 ha) is one of the largest wetlands in the Rosedale Hills, 35 km north-west of Nelson, New Zealand. It has an extensive cover of Salix fragilis L. (crack willow) and has been hypothesised to be a source of groundwater recharge for the Moutere aquifers, an important local groundwater system. However the wetland could also be a groundwater discharge zone, because of the geological boundary that it straddles. The overall aim of this study was to determine the direction of groundwater flux of the wetland by measuring the water balance, with particular emphasis on the transpiration rates from the crack willow trees.
The average daily transpiration (measurement was for 230 days) of crack willows in the wetland (6.4 mm/day) was close to twice the potential evapotranspiration (PET) for grassland (3.9 mm/day). The highest measured willow transpiration rate was 12.4 mm/day and the lowest was 0.8 mm/day. High transpiration from crack willows was due to the horizontal energy fluxes (advective energy), tree physiological characters and high soil water content.
The study established that the wetland is a groundwater discharge zone with, on average for the two summer periods (2008 and 2009), the net groundwater discharge being 4.8 mm/day. The daily water balance results between two major rainfall events showed that the initial discharge source was from the surrounding hills and later stabilized at around 6 to 14 mm/day. It was believed to be a contribution from the shallow and deep aquifers or a combination of local region inflow and aquifers.
The water balance showed that the main loss of water through the hydrological system of the wetland during summer was from the high transpiration of willows (7.7 mm/day). The extent of water savings estimated for the 16 ha wetland through a hypothetical situation of willow removal, and the assumption that it is filled with open water without any canopy cover, was 688 m3/day. However this water savings rate if applied to a large area of crack willow stands would be quite high. On similar lines it is important to understand the transpiration rates of other wetland tree species in New Zealand. This information would help in preparing regional council plans for the introduction of tree species in the wetland for better management of the water resources and sustainable ecosystem management.
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Cheveia, Etevaldo Calisto. "Necessidades hídricas do olival regado no Alentejo." Master's thesis, Universidade de Évora, 2012. http://hdl.handle.net/10174/15044.
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As necessidades hídricas da oliveira são uma questão muito importante na região
mediterrânica devido as condições climáticas da zona, que é caracterizada por verões
muito quentes e secos. Este cenário obriga a que se tenha que recorrer a sistemas de rega
para fornecer água à cultura, para que se obtenham produções aceitáveis comercialmente
(comercialmente viáveis).
O presente trabalho foi realizado em duas herdades, Álamo de Cima e Olivais do Sul. A
primeira segue o regime intensivo de plantação, com aproximadamente 300 árvores por
hectare e a segunda o regime super-intensivo, com cerca de 2000 árvores por hectare. O
objectivo do ensaio foi avaliara transpiração de dois olivais (intensivo e super-intensivo)
com o método de fluxo de seiva, ao longo do período de rega; avaliar também a
evapotranspiração cultural usando o método do balanço hídrico e os coeficientes culturais
dos dois olivais ao longo do período de rega;e relacionar a transpiração com o balanço e
potenciaishídricos, e com a produção dos dois olivais.
Em cada herdade foram testadas duas dotações de rega diferentes, FI (rega praticada e
conduzida pelos técnicos na herdade) e DI (rega a testar). Para a herdade Álamos de
Cima, a modalidade FI usa gotejadores de 1,6 L/hde débito para a rega do agricultore
gotejadores de 2,3 L/h para a modalidade DI (rega a testar). Para a herdade Olivais do
Sul, a modalidadeFI (rega praticada e conduzida pelos técnicos na herdade) tem
gotejadores de 2,3 L/h, com gotejadores de 1,6 L/h para a modalidade DI (rega a testar).
Em ambas as herdades e modalidades de rega, a calendarização e os tempos de rega são
da responsabilidade do agricultor, daí a substituição de rampas com diferentes
gotejadores para se obter as dotações desejadas nas modalidades a testar.
Em cada modalidade de rega foram escolhidas 3 linhas consecutivas de árvores no olival
onde se instalou, na segunda linha e em 3 árvores consecutivas, sondas de fluxo de seiva
para medir a transpiração em contínuo, servindo as outras linhas de bordadura. Instalaram
– se tubos de acesso à sonda de humidade no solo para se monitorar a humidade e deste
modo calcular – se a variação do armazenamento, que é uma das componentes da
equação do balanço hídrico para a determinação da evapotranspiração cultural.Na herdade do Álamo de Cima a transpiração da cultura foi maior para a modalidade DI
(com gotejadores de 2,3 L/h e dotação mais elevada) com 202 mm, enquanto que a FI
(com gotejadores de 1,6 L/h e menor dotação) registou 177,2 mm. Na herdade Olivais do
Sul a transpiração foi maior para a modalidade FI (de maior dotação)com 349,1
mm,enquanto que a DI (de menor dotação)registou 345,2 mm. Esta transpiração
corresponde à transpiração integral do período, que foi de 06/05 a 06/10/11.
A evapotranspiração cultural pelo método do balanço hídrico foi de 435,1 mm para a
modalidade FI, e de 412,8 mm para a modalidade DI epara a herdade dos Olivais do Sul,
correspondendo ao já verificado com a transpiração obtida pelo método do fluxo de seiva.
Para a herdade - Álamo de Cima, a evapotranspiração foi de 327,3 mm para a modalidade
FI e 312,3 mm para a modalidade DI.
Em relação à produção, os rendimentos foram de 1,78 toneladas por hectare para a
modalidade FI e de 2,45 toneladas por hectare para a modalidade DI e para a herdade do
Álamo de Cima. Na herdade Olivais do Sul o rendimento foi de 18,7 toneladas por
hectare para a modalidade FI e de 14,1 toneladas por hectare para a modalidade DI; ABSTRACT:The water requirements of olive are very important issuein the Mediterranean region due
to the climatic conditions of the area which is characterized by very hot summer and dry.
This scenario obliges to resort to watering systems to supply water to the crop for the
achievement of commercially acceptable yields (commercially viable).
This study was conducted at two farms, Alamo de Cima and Olivais do Sul. The first uses
intensive regime (around 300 trees per hectare) and the second super-intensive (around
2000 trees per hectare). The aim of this study was to calculate the transpiration of two
groves (intensive and super-intensive) with the method of sap flow throughout the
irrigation period; calculate the crop evapotranspiration by water balance method and the
crop coefficients of the two groves along the irrigation period; relate transpiration with
the water balance and yield of the two groves.
In each farm were tested two modes of irrigation. For Alamo de Cima farm, FI (irrigation
practiced on the farm) uses drip irrigation with 1,6L/h and DI (irrigation test) with
2,3L/h. For the farm Olivais do Sul FI (irrigation practiced on the farm) uses drip
irrigation with 2,3 L/h and 1,6L/ h for DI (irrigation test).
In each mode of irrigation were chosen three consecutive rows of olive trees where were
settled in the second rowon 3 consecutive trees sap flow probes to measure the
transpiration continuously. Acess tubes were settled in the soil to monitor soil moisture in
order to calculate the variation of water storage which is a component of the water
balance equation for the determination of evapotranspiration.
In the Alamo de Cima farm the transpiration was higher for DI mode with 202 mm while
the FI recorded 177,2 mm. In the Olivais do Sul farm the transpiration was higher for FI
mode with 349,1 mm while the DI recorded 345,2 mm. This transpiration corresponds to
transpiration for the period from 06/05 to 06/10/11.Evapotranspiration by the water balance method was 435,1 mm for the FI mode and
412,8mm for DI mode for the Olivais do Sul farm. For the Alamo de Cima farm the
evapotranspiration was 327,3 mm for the FI mode and 312,3 mm for DI mode.
In relation to production, yields were 1,78 t/ha for the FI mode and 2,45 t/ha for DI mode
for the AC farm. In the OS farm the yield was 18,7 t/ha for the FI mode and 14,1 t/ha for
DI mode, reflecting the added water, and the transpiration and evapotranspiration.
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Pasqualotto, Gaia. "Transpiration of hazelnut (Corylus avellana L.) orchards in response to different climatic conditions and implications for water management." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3423308.
Full textAbstract:
Plants are unquestionably at the basis of human life as they are directly or indirectly a source of food, but the agricultural sector accounts for more than 80% of water consumption. Agricultural production cannot ignore water supply to meet market demands, while it faces growing water shortages, droughts and heat waves. In this sense, it is paramount to manage water resources in a sustainable way by understanding the water responses of species to different climates.
The European hazelnut is an expanding orchard tree, which has now established in all continents to answer the increasing demand for nuts from the food industry. Trees face the challenge of acclimating to new areas, while remaining productive. In this situation, still no precise knowledge exits about the average transpiration of hazelnut orchard under standard irrigation and thus about the real irrigation needs respect to its environment. The few studies on hazelnut water use are mainly leaf-based or hardly transferred to growers.
This research focuses on three main topics in the perspective of providing useful reference for orchard managers set in different climatic contexts: I) to identify the pattern of transpiration response to different climates, irrigation and cultivars. II) To estimate the transpiration at the tree level and propose a realistic tool for growers to reintegrate water loss. III) Explore the links and limitations of transpiration activity and carbon gain processes.
We set a long-term experiment across three growing seasons (from 2016 to 2019) on eight orchards in Chile, Australia, Italy, France and Republic of Georgia, involving two cultivars: Tonda Gentile delle Langhe and Tonda di Giffoni. We monitored in continuous the sap flow with Granier’s thermal dissipation probes (TDPs), the meteorological parameters and the soil water content. Tree biometrics and orchard features were recorded as well. TDPs were calibrated with a liquid flow meter applied to a potometric system.
The transpiration responses showed to be linearly correlated to the vapor pressure deficit of the atmosphere (VPD) until 20hPa. The radiation intensity produced different responses in the two hemisphere, but cultivar and doubled irrigation had little impact. The calibration of TDPs lead to the correction of the Granier’s equation with parameters suitable for hazelnut. This, together with the estimation of the tree leaf area, allowed to derive a range of transpiration per unit of leaf (1-2.55 l m-2day-1). This is the basis for a water loss reintegration strategy by knowing the mean daily VPD. The link between transpiration and carbon assimilation was considered to highlight the interval of VPD at which the canopy conductance, and thus the potential carbon assimilation, is maximized. A conclusive ancillary study shows through the manipulation of C sources and sinks that the nut production depends on C previously stored in the stem showing that branches are not fully carbon autonomous.Le piante sono indiscutibilmente alla base della vita umana poiché sono direttamente o indirettamente fonte alimentare, ma il settore agricolo pesa per più dell’80% sul consumo di acqua. La produzione agricola non può prescindere dall’apporto idrico per raggiungere le richieste del mercato, mentre deve fronteggiare una crescente scarsità di acqua, eventi siccitosi e ondate di calore. In questo senso, diviene fondamentale gestire le risorse idriche in modo sostenibile comprendendo le risposte idriche delle specie ai diversi climi. Il nocciolo è un albero da frutto in grande espansione, che si è oggi affermato in tutti i continenti in risposta alla richiesta di nocciole da parte dell’industria alimentare. I noccioli debbono al contempo acclimatarsi alle nuove aree e rimanere produttivi. In questa situazione non c’è ancora una precisa conoscenza rispetto alla traspirazione media di noccioleti irrigati e quindi alle loro necessità irrigue calate nel contesto climatico. I pochi studi sull’ utilizzo dell’acqua nel nocciolo rimangono relativi alle dinamiche fogliari o sono difficili da trasferire agli agricoltori. Lo scopo di questa ricerca verte su tre scopi principali nella prospettiva di essere un riferimento per i gestori dei corileti che operano in diversi contesti climatici: I) Identificare la risposta traspirativa di piante adulte in diversi climi, irrigazioni e cultivar. II) Stimare la traspirazione al livello di albero e, sulla base di ciò, proporre un approccio realistico per reintegrare le perdite traspirative volto ai corilicoltori. III) Esplorare le connessioni e le limitazioni alla traspirazione e ai processi di acquisizione del carbonio. Si è installato un esperimento a lungo termine attraverso tre stagioni vegetative (2016-2019) in otto diversi corileti in Cile, Australia, Italia, Francia e Repubblica della Georgia, coinvolgendo due cultivar: Tonda Gentile delle Langhe and Tonda di Giffoni. Il flusso di linfa è stato monitorato con delle sonde a dissipazione termica di Granier (TDP). Sono stati misurati parametri meteorologici, contenuto idrico del suolo e parametri biometrici dei corileti. I TDP sono stati calibrati attraverso un misuratore di flusso e un approccio potometrico. Le risposte traspirative si sono dimostrate linearmente correlate con il deficit di pressione di vapore atmosferico (VPD) fino a circa 20 hPa. L’intensità di radiazione si è anche rivelata importante nel diversificare le risposte tra i due emisferi, ma la cultivar e le diverse strategie irrigue hanno avuto un effetto irrilevante nel diversificare le risposte traspirative. La calibrazione dei TDP ha condotto alla correzione dell’equazione di Granier con parametri adatti al nocciolo. Questo, insieme alla stima dell’area fogliare ha permesso di individuare un intervallo di traspirazione per unità di area fogliare (1-2.5 l m-2 giorno-1). Tale risposta è alla base di una strategia di reintegro delle perdite traspirative che utilizza il VPD medio come principale predittore della traspirazione totale giornaliera. Il legame tra traspirazione e assimilazione potenziale di carbonio è stato considerato per far emergere l’intervallo di VPD in cui la conduttanza di chioma è massimizzata, e quindi, anche il potenziale di assimilazione. Uno studio ancillare conclusivo mostra che per il riempimento delle nocciole la specie utilizza anche carboidrati precedentemente immagazzinati nel fusto oltre che a quelli forniti dalle foglie dell’anno.
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Boehringer, Davi. "Determinação da transpiração da cana-de-açúcar por métodos térmicos." Universidade Federal de Viçosa, 2010. http://locus.ufv.br/handle/123456789/5244.
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The main objective of this research was to evaluate the applicability of thermal methods for measuring sugarcane sap flow under different environmental conditions. For the evaluation of methods (energy balance and heat pulse) measurement events were conducted in a greenhouse according to the transpiration and the sugarcane sap flow under cloudy skies and partly cloudy conditions. The experiment was conducted at the experimental field of Agricultural Meteorology sector from the Department of Agricultural Engineering, Federal University of Viçosa, Minas Gerais. The monitoring of meteorological data within the greenhouse was performed by a computerized data acquisition. It was able to monitor the sap flow from the due sugarcane culture and control the electric power applied to the resistive terminals of the heat source. Based on the results, was noticed that the water needing for the sugarcane culture in hourly and daily scale, may be adequately determined by means of sap flow measurements for using the method of energy balance according to the segment of stem. However, even with the large volume of stored sap in the stems and the low sap flow speed compared to other cultures, the heat pulse method could not be implemented through the methodology proposed on a classical knowledge literature. Only with the application of longer pulses in a scale of minutes instead of seconds, it was possible to detect temperature variations that could be measured by the current data acquisition system. Thus such in order to be applied to the studied sugarcane, the theory of heat pulse method needs to be adapted from specific studies in that matter. It was noticed that, both as the low stream temperature, as the high stream temperature of the heat source show differences after the application of heat pulse in different times of the day, responding with transpiration changing compared to a day of clear skies. It was also observed that the component of heat storage in the stem cannot be disregarded for the energy balance as proposed by some authors for measurements performed in other cultures. Moreover, considering the significant diameter of the stems is necessary to install four thermocouples to obtain the temperature of the sap in the levels above and below from the heat source, two from those inserted in the center and other two in its surface. An additional thermocouple should be placed in the center of the blanket insulation, at the heat source, to quantify the axial and radial conduction of heat. The transpiration of individual sugarcane plants was slightly underestimated by the method of energy balance in the hourly scale (RMSE = 14,6 g planta-1 h-1; MBE = -4,7 g planta-1 h-1; r = 0,9065; d = 0,9432) and daily (RMSE = 97,1 g planta-1 d-1; MBE = -56,2 g planta-1 d-1; r = 0,9369; d = 0,9488), with differences about 4% compared to maximum values of transpiration measured. With the procedure of the new research for improvement of this technique, the energy balance method has great potential to become a referential technique for calibration of other similar methods in order to quantify the water flow of vapor from sugarcane to the atmosphere.
O objetivo principal foi avaliar a aplicabilidade de métodos térmicos para medição do fluxo de seiva da cana-de-açúcar sob condições ambientais distintas. Para a avaliação dos métodos (balanço de energia e pulso de calor), foram realizadas campanhas de medição da transpiração e do fluxo de seiva da cana-de-açúcar em uma casa de vegetação. O experimento foi conduzido na área experimental do setor de Meteorologia Agrícola, pertencente ao Departamento de Engenharia Agrícola da Universidade Federal de Viçosa, Minas Gerais. O monitoramento dos dados meteorológicos no interior da casa de vegetação foi realizado por meio de um sistema computadorizado de aquisição de dados. Ele foi capaz de monitorar o fluxo de seiva da cana-de-açúcar e de controlar a potência elétrica aplicada nos terminais resistivos da fonte de calor. Constatou-se que as necessidades hídricas da cultura da cana-deaçúcar, em escala horária e diária, podem ser determinadas, de forma adequada, por meio de medições do fluxo de seiva com o método do balanço de energia em um segmento de caule. No entanto, em decorrência do grande volume de seiva armazenada nos colmos e da baixa velocidade de deslocamento da seiva em comparação com outras culturas, o método do pulso de calor não pôde ser implementado por meio da metodologia clássica proposta na literatura. Somente com a aplicação de pulsos mais prolongados, em escala de minutos ao invés de segundos, foi possível detectar variações de temperatura que pudessem ser mensuradas pelo sistema de aquisição de dados. Desta forma, para que possa ser aplicada para a cana-de-açúcar, a teoria do método do pulso de calor precisa ser adaptada a partir de estudos específicos. Notou-se que, tanto a temperatura da seiva acima, quanto a temperatura abaixo da fonte de aquecimento comportam-se de maneira distintas após a aplicação do pulso de calor nos diversos horários do dia, respondendo às variações da transpiração para um dia de céu claro. Foi observado também que o componente do armazenamento de calor no caule não pode ser desconsiderado no balanço de energia como foi proposto por alguns autores para medições realizadas em outras culturas. Por outro lado, devido ao diâmetro expressivo dos colmos, é necessário instalar quatro termopares para obtenção da temperatura da seiva nos níveis acima e abaixo da fonte de aquecimento, sendo dois inseridos no centro e outros dois na superfície do colmo. Um termopar adicional deve ser colocado no centro da manta de isolamento térmico, ao nível da fonte de aquecimento, para quantificação da condução axial e radial de calor. A transpiração de plantas individuais de cana-de-açúcar foi ligeiramente subestimada pelo método do balanço de energia em escala horária (RMSE = 14,6 g planta-1 h-1; MBE = -4,7 g planta-1 h-1; r = 0,9065; d = 0,9432) e diária (RMSE = 97,1 g planta-1 d-1; MBE = -56,2 g planta-1 d-1; r = 0,9369; d = 0,9488), com diferenças da ordem de 4% em relação aos valores máximos de transpiração medidos. Com a realização de novas pesquisas para aprimoramento desta técnica, o método do balanço de energia tem grande potencial para se tornar a técnica de referência na calibração de outros métodos utilizados para quantificação do fluxo de vapor d’água da cana-de-açúcar para a atmosfera.
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Carvalho, Kassio dos Santos. "Medida e modelagem da evapo(transpi)ração de um canavial irrigado em função do manejo da palhada." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-18052017-154117/.
Full textAbstract:
A cultura da cana é importante para o agronegócio brasileiro. O manejo adequado da palhada da cana-de-açúcar no solo pode influenciar no desenvolvimento e no crescimento da cultura, podendo resultar em ganhos ambientais e econômicos. Neste trabalho, objetivou-se avaliar o efeito do manejo com palha (CP) e sem palha (SP) na evapotranspiração de um canavial irrigado. Um experimento foi conduzido em canavial irrigado com dois tratamentos (mantendo-se 100% da palhada e sem cobertura de palha sobre o solo). Neste experimento, a evapotranspiração foi medida a partir do balanço hídrico \"in situ\" do solo (ETc-BHS) e pelo método da razão de Bowen (ETc-MRB) e a transpiração utilizando-se sensores de fluxo de seiva (FS). A evaporação do solo foi estimada com base em dados da cultura e meteorológicos. A modelagem da transpiração e de seus componentes baseou-se na abordagem no \"modelo da grande folha\" (\"big leaf model\") proposto por Monteith. Para tanto, foram definidos e avaliados submodelos para a simulação do saldo de radiação no dossel, da resistência aerodinâmica, da resistência de cobertura no ambiente da cultura. Ao longo do ciclo da cultura, análises biométricas foram realizadas a cada 30 dias e esses dados utilizados na parametrização do modelo. O desempenho dos submodelos e do modelo parametrizado de Penman-Monteith (PM) foi estatisticamente avaliados. Avalia-se um modelo para estimativa da evaporação em função da cobertura da palhada. O cultivo de cana-de-açúcar utilizando os resíduos vegetais favorece o incremento da transpiração, da evapotranspiração da cultura (ETc) e reduz a evaporação de água no solo. A palha influenciou as variáveis biométricas da cultura, como perfilhamento, massa fresca da parte aérea (MFPA) e massa seca da parte aérea (MSPA). Ao relacionar a transpiração estimada com o modelo de PM com a medida com FS, verifica-se um coeficiente de determinação (R2) de 0,72 e de 0,48 e um coeficiente angular (a) de 1,22 e 0,92, para a área manejada CP e SP, respectivamente. A evaporação de água no solo é maior na área SP, principalmente nos períodos com precipitações acima de 40 mm. Quando se relaciona a ETc-BHS e a ETc-MRB com a ETc estimada com base no método de PM, nota-se um R2 de 0,67 e 0,54 na área CP e 0,59 e 0,54 para a área SP, respectivamente. Independente do manejo adotado, aos 302 dias após o corte, o canavial apresentou ATR, POL e % de fibra ideal para a comercialização. O teor de clorofila na área manejada CP é superior ao manejado SP. O cultivo de cana-de-açúcar utilizando os resíduos vegetais favorece o incremento da transpiração, da ETc e reduz a evaporação de água no solo.Cane culture is important for Brazilian agribusiness. Proper management of sugarcane trash in the soil can influence the development and growth of the crop, which can result in environmental and economic gains. The objective of this study was to evaluate the effect of trash management (CP) and without trash (SP) on the evapotranspiration of an irrigated sugar cane. An experiment was conducted in irrigated sugar cane fields with two treatments (100% of the trash and without trash cover on the soil). In this experiment, evapotranspiration was measured from soil water balance (ETc-BHS) and the Bowen ratio method (ETc-MRB) and transpiration using sap flow sensors (FS). Soil evaporation was estimated based on crop and meteorological data. The modeling of the transpiration and its components was based on the approach in the \"big leaf model\" proposed by Monteith. For that, submodels were defined and evaluated for the simulation of canopy radiation balance, aerodynamic resistance, and cover resistance in the culture environment. Throughout the crop cycle, biometric analyzes were performed every 30 days and these data were used in the parameterization of the model. The performance of the submodels and the parameterized model of Penman-Monteith (PM) was statistically evaluated. A model for estimation of evaporation is evaluated as a function of the trash cover. The cultivation of sugarcane using the vegetal residues favors the increase of transpiration, evapotranspiration of the crop (ETc) and reduces the evaporation of water in the soil. The trash influenced the biometric variables of the crop, such as tillering, fresh mass of aerial part (MFPA) and dry mass of aerial part (MSPA). When correlating the estimated transpiration with the PM model with the FS measurement, it is verified a determination coefficient (R2) of 0.72 and 0.48 and an angular coefficient (a) of 1.22 and 0.92, for the managed area CP and SP, respectively. The water evaporation in the soil is higher in the SP area, especially in periods with rainfall above 40 mm. When ETc-BHS and ETc-MRB are related to ETc estimated on the basis of the PM method, an R2 of 0.67 and 0.54 is observed in the CP area and 0.59 and 0.54 for the area SP, respectively. Regardless of the management adopted, at 302 days after cutting, the sugarcane plantation presented ATR, POL and% of fiber ideal for commercialization. The chlorophyll content in the managed area CP is superior to the managed SP. The cultivation of sugarcane using the vegetal residues favors the increase of the transpiration, ETc and reduces the evaporation of water in the soil.
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Francisco, João Paulo. "Estimativa da transpiração de pinhão-manso com a utilização do método de dissipação térmica." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/11/11152/tde-16082017-153135/.
Full textAbstract:
Atualmente o mundo vive uma fase de mudança da matriz energética, onde fontes mais limpas e renováveis de energia estão sendo cada vez mais utilizadas. Considerando o eminente cenário de escassez dos recursos hídricos, além da necessidade de produzir energia mais limpa, existe a necessidade de racionalizar o uso da água e para isso é preciso estudar o consumo hídrico das culturas. Assim, este projeto terá como objetivos calibrar e utilizar medidas de fluxo de seiva obtidas pelo método de dissipação térmica (MDT) para determinar a transpiração do pinhão-manso (Jatropha curcas L.). Para a calibração foram utilizadas plantas de pinhão-manso cultivadas em casa de vegetação dentro de vasos de 250 L. Estes vasos foram acondicionados sobre lisímetros de pesagem e tiveram sua superfície coberta para evitar a evaporação da água do solo. A calibração foi realizada durante 60 dias consecutivos, quando durante os primeiros 15 dias o solo foi mantido com umidade próxima da condição de capacidade de vaso por meio de irrigações frequentes, seguido de 30 dias de redução da umidade do solo devido a supressão da irrigação e de 15 dias finais com o retorno da irrigação para a recuperação da hidratação das plantas. A transpiração foi determinada nos lisímetros e estes dados foram utilizados para calibrar as medidas obtidas por sensores de fluxo de seiva inseridos no tronco das plantas. Após a calibração, os sensores foram instalados em campo para monitorar a transpiração de plantas cultivadas sob irrigação por pivô central, gotejamento e sem irrigação. Aliado a diferentes tipos de poda a que foram submetidas as plantas, avaliou-se a combinação do consumo de água das plantas de pinhão-manso associado a estes tratamentos de podas. Como esperado o método de dissipação térmica apresentou-se como sendo confiável para determinação da transpiração de pinhão-manso, permitindo que a metodologia pudesse ser utilizada em campo. Foi verificado efeito significativo da irrigação, dos tipos de poda e da época de avaliação após a poda para a altura de plantas, diâmetro e volume de copa e IAF. Observou-se valores de ETc de 6,96; 7,54 e 6,57 mm dia-1 para os tratamentos de irrigação localizada, pivô central e sem irrigação, respectivamente.Today the world is going through a phase of changing the energy matrix, where cleaner and renewable sources of energy are being used more and more. Considering the imminent scenario of scarcity of water resources, in addition to the need to produce cleaner energy, there is a need to rationalize the use of water and for this we must study the water consumption of crops. Thus, this project will aim to calibrate and use sap flow measurements obtained by the thermal dissipation probe to determine Jatropha curcas L. transpiration. For the calibration, jatropha plants grown under greenhouse conditions were used in 250 L vessels. These vessels were placed on weighing lysimeters and had their surface covered to avoid evaporation of soil water. The calibration was carried out during 60 consecutive days, which during the first 15 days the soil was maintained with humidity near the pot capacity by means of frequent irrigations, followed by 30 days of soil moisture reduction due to suppression of irrigation and of 15 days with the return of irrigation to the recovery of plant hydration. The transpiration was determined in the lysimeters and these data were used to calibrate the measurements obtained by sap flow sensors inserted in the trunk of the plants. After the calibration, the sensors were installed in the field to monitor the transpiration of plants cultivated under central pivot irrigation, drip irrigation and without irrigation. Allied to the different types of pruning to which the plants were submitted, the combination of the water consumption of the jatropha plants associated to these pruning treatments was evaluated. As expected, the thermal dissipation method proved to be reliable for the determination of perspiration of Jatropha, allowing the methodology to be used in the field. It was verified a significant effect of irrigation, pruning types and evaluation period after pruning for plant height, canopy diameter and volume and LAI. ETc values of 6.96; 7.54 and 6.57 mm day-1 for the treatments of localized irrigation, central pivot and without irrigation, respectively.
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Grime, Victoria Louise. "Thermal methods for measuring sap flow through intact plant stems : an evaluation of methods and their application for determining the factors controlling transpiration in a stand of heterogeneous natural vegetation." Thesis, University of Reading, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314808.
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Vellame, Lucas Melo. "Relações hídricas e frutificação de plantas cítricas jovens com redução de área molhada do solo." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-11022011-085755/.
Full textAbstract:
A citricultura é um setor de grande importância para o país na geração de divisas, formação de renda e capital. Um dos fatores críticos no sucesso de um sistema de irrigação localizada é a definição em projeto da fração de área molhada no solo. Face às dificuldades técnicas encontradas nesse tipo de estudo, até o presente, inexistem na literatura científica trabalhos confiáveis que estabeleçam os valores ótimos de fração de área molhada no solo para as diferentes culturas e condições edafoclimáticas. Esse trabalho teve como objetivo principal avaliar o efeito do molhamento parcial do solo para plantas jovens de laranja Valência sob porta-enxerto de citrumelo Swingle e limão Cravo em dois tipos de solo. Os objetivos secundários foram: a) Avaliar o método da sonda de dissipação térmica na estimativa da transpiração em laranja Valência e b) Estabelecer as relações entre a transpiração das plantas, sem restrição de área de solo, molhado e a demanda atmosférica. O experimento foi conduzido em estufa nas dependências do Departamento de Engenharia de Biossistemas da ESALQ/USP. Foi testado o molhamento de 12,5% da área do solo. Mudas de laranja foram plantadas em caixas de 500 L internamente divididas em compartimentos. Determinou-se simultaneamente a transpiração de todas as plantas através de sondas de dissipação térmica, o conteúdo de água no solo, o crescimento das plantas (área foliar e diâmetro de caule) e o número total de frutos por planta. Inicialmente todas as plantas tiveram 100% do volume de solo ocupado pelas raízes irrigado, sendo determinada a contribuição relativa de cada compartimento da caixa na transpiração. Completada a secagem dos compartimentos não irrigados, foi calculado o percentual da transpiração relativa a 100% de área molhada do solo pela relação entre transpiração de cada planta e a transpiração média das plantas com 100% da área do solo molhado. De acordo com os resultados, conclui-se que ocorre redução da transpiração pela restrição da área de solo molhado, sendo esta redução influenciada não só pelo tipo de solo e porta-enxerto, como também pelo número de dias após início da irrigação parcial, demanda evaporativa da atmosfera e fase fenológica da planta. A adaptação do sistema radicular à redução da área molhada ocorreu em torno de 156 dias. Apesar da redução da taxa transpiratória, não houve diferença significativa entre os tratamentos em relação ao crescimento vegetativo e número de frutos por planta. A transpiração das plantas foi influenciada pelo tipo de porta-enxerto utilizado, do crescimento em área foliar e da fase fenológica, sendo que sua relação com a evapotranspiração de referência não é linear em toda faixa de demanda evaporativa da atmosfera. O método da sonda de dissipação térmica, com calibragem específica e correção dos gradientes térmicos naturais no caule, mostrou-se eficaz na avaliação da transpiração de plantas jovens de laranjeira.The citrus industry is a great important sector to the Brazilian country to generate foreign currency income and capital formation. The determination of the fractional wetted area in the soil is a critical factor in the success of an irrigation system project. Due to the technical difficulties to find out dates in this kind of study, there are no reliable studies in the scientific literature to establish the optimal values of fractional wetted area for different crops, soil and weather. This study aims to evaluate the effect of partial wetting of the soil for Valencia orange under the rootstock Swingle and Rangpur in two soil types. As secondary objectives: a) To evaluate the method of heat dissipation probe in the transpiration estimative in the Valencia orange plant, b) to establish the relationship between the atmospheric demand and plant transpiration, without restriction wetted area. The experiment was conducted in a greenhouse in the Biosystems Engineering Department of ESALQ/USP, Piracicaba-SP, Brazil. It was tested the wetness of 12.5% of the area of soil. For this, orange seedlings were planted in boxes of 500 L internally divided into compartments. It was simultaneously determined transpiration of all plants using heat dissipation probes (sap flow), measured the soil water content, plant growth (leaf area, stem diameter) and the total number of fruits per plant. Initially, it was irrigated 100% of root system of all plants and it was determined the contribution of each compartment of the box in the plant transpiration by the difference in water storage in the soil and measured plant transpiration. When it was completed the drying of not irrigated compartment, it was calculated the percentage of transpiration on 100% of the wetted soil area by the relationship between transpiration of each plant and the average of plant transpiration with 100% of the wetted area. According to the results can be conclude that occur reduction in the transpiration flow due to the restricting of wet soil area and this reduction is not only influenced by soil type and rootstock, but also due to the number of days after onset of partial irrigation, atmospheric evaporative demand and plant phenological stage. The adaptation of the root system to the reduction of the wet soil volume occurred around 156 days. Despite of the reduction in transpiration rate, it was not observed significant difference between treatments in relation to vegetative growth and fruit number per plant. Plant transpiration was influenced by the type of rootstock used, leaf area growth and phenological stage. However the relationship between the plant transpiration and EToPM is not linear across the range of atmospheric evaporative demand. The method of heat dissipation probe, calibrated specifically for the study and with correction of the thermal natural gradient in the trunk was effective in the evaluation of the seedlings of orange transpiration.
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Ballester, Lurbe Carlos. "Regulated deficit irrigation in citrus: agronomic response and water stress indicators." Doctoral thesis, Universitat Politècnica de València, 2013. http://hdl.handle.net/10251/28582.
Full textAbstract:
In the Mediterranean area water is a scarce natural resource and periods of drought are frequent. It is then important to increase water use efficiency of irrigated crops. In order to achieve this, one promising option is regulated deficit irrigation (RDI). RDI consists in reducing water application during stages of crop development when yield and fruit quality have low sensitivity to water stress. Full irrigation is provided during the rest of the season to maintain production and fruit quality at adequate levels (Behboudian and Mills, 1997). In citrus, flowering and fruit set are sensitive periods to water restrictions, because water stress during this period increases fruit drop (Ginestar and Castel 1996). The more appropriate phenological period for applying water restrictions seems to be the summer period providing that water applications returned at full dosage sufficiently before harvest in order to allow for compensation in fruit growth (Cohen and Goell 1988).
Previous work by González-Altozano and Castel (1999) showed the feasibility of applying RDI in 'Clementina de Nules' and identified threshold values of plant water stress that allowed water savings of about 10-20% without any detrimental effect on yield or fruit size. It would be desirable now to study the extrapolation of these results to commercial orchards of citrus and assess the use of RDI in different citrus cultivars.
Two RDI strategies (RDI-1, irrigated at 50% of crop evapotranspiration (ETc) during summer and; RDI-2, irrigated at 35% ETc during the same period to RDI-1) will be compared with a control treatment irrigated at full requirements. As the level of water stress reached by trees is the important factor when RDI strategies are applied, the study of accurate water stress indicators for citrus is also needed. Thus, during the period of water restrictions the use of sap flow and canopy temperature measurements, obtained by thermal imaging or by means of fixed infrared thermometer sensors, will be assessed and compared to classical methods like stem water potential and stomatal conductance.Ballester Lurbe, C. (2013). Regulated deficit irrigation in citrus: agronomic response and water stress indicators [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/28582
TESIS
Premiado
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Karasawa, Shiguekazu. "Evapotranspiração de cafezal semi-adensado irrigado por gotejamento e sua relação com a evapotranspiração de referência." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11131/tde-30082006-154712/.
Full textAbstract:
O uso crescente de irrigação na cafeicultura devido ao cultivo em áreas com maior deficiência hídrica exige conhecimento sobre o consumo de água da cultura. Para contribuir para esse conhecimento, a evapotranspiração global do cafezal (ETc) e sua partição nos fluxos componentes evapotranspiração das linhas de cafeeiros (ETlin), evapotranspiração das entrelinhas (ETel) e a transpiração dos cafeeiros (T) foram determinadas em um cafezal de Coffea arabica cv. Obatã IAC-1669-20, cultivado em Piracicaba, SP, em espaçamento de 3,50 m x 0,90 m, irrigado por gotejamento e idade entre 3 a 4 anos, com medidas de setembro/04 a maio/05 e em setembro e outubro de 2005. ETc foi determinada pelo método de balanço de energia-razão de Bowen, ETlin por lisímetros de células de carga, sendo estes usados em vários períodos com o solo coberto com plástico para determinação direta da transpiração e para calibrar o método da sonda de dissipação térmica, usado na determinação do fluxo de seiva (FS) dos cafeeiros. Em abril-maio/05, FS foi usado como uma estimativa de T diária. ETc e componentes foram relacionados com a evapotranspiração de referência estimada pelos métodos de Penman- Monteith (ETo 1) e do tanque classe A (ETo 2). O calor latente de vaporização (LE) representou a maior fração na partição da energia disponível (saldo de radiação menos fluxo de calor no solo), com variação de 73 a 80 % ao longo dos meses, não se podendo descartar a contribuição de calor advectivo para os valores encontrados nos meses secos. ETc cresceu a partir de setembro/04 a fevereiro/05 (2,75 a 4,58 mm d-1), refletindo principalmente o incremento de área foliar e diminuindo, posteriormente, até maio/05 (3,13 mm d-1) com a diminuição da demanda atmosférica. Em setembro-outubro/05 os valores foram maiores (2,93 e 4,29 mm d-1) do que os observados no mesmo período em 2004, sendo o aumento da área foliar uma das responsáveis pelo fato. A relação ETc/ETo (Kc global da cultura) foi maior quando calculada com ETo 1 do que com ETo 2, sendo os valores crescentes até janeiro/05 (1,20 com ETo 1 e 1,21 com ETo 2) mas com o menor valor em setembro/04 (0,67 e 0,54) e com diminuição da tendência de acréscimo em fevereiro/05 (1,17 e 0,73), provavelmente pela regulação estomática dos cafeeiros devido à alta demanda atmosférica nesses meses. A contribuição de ETlin para a ETc variou pouco entre setembro/04 e fevereiro/05 (24 % a 31 %), aumentando em março e abril (35 % e 40 %), valores esses próximos da proporção entre a área de solo coberta pelos cafeeiros e a área total (linhas+entrelinhas). A relação ETlin/ETo variou entre 0,20 (uso de ETo 1) e 0,16 (com ETo 2) em setembro/04 a 0,36-0,47 (com ETo 1) e 0,25-0,49 nos outros meses. A T dos cafeeiros por unidade de área foliar diminuiu com o aumento da área foliar. A relação T/ETlin variou de 72 % em fevereiro a 46 % em abril, sendo o valor de T/ETo (Kc basal) variável entre 0,13 (com ETo 1) e 0,10 (com ETo 2) em setembro a 0,30 (independente do método de estimativa de ETo) em abril e maio/04, provavelmente refletindo a menor atividade fisiológica.The increasing use of irrigation in coffee plantations in Brazil, due to the deplacement of the crop to areas where water deficit occurs, requires knowledge about crop water consumption. Aiming to know more about coffee plantation water consumption, daily crop evapotranspiration (ETc) and its partition in row evapotranspiration (ETrow), interrows evapotanspiration (ETint) and coffee plants transpiration (T) were determined in a drip-irrigated coffee plantation (cv. Obatã IAC-1669-20), cultivated at 3.5 m between rows and 0.9m between plants, in Piracicaba, São Paulo State, Brazil. The ET and wheater variables measurements were carried out from September 2004 to May 2005 and from September to October 2005. ETc was determined by he Bowen ratio-energy balance method, ETrow by load cell lysimeters and T with lysimeters with soil surface covered with plastic or by sap flow determined with the thermal dissipation probe method (TDP). Lysimeters were also used to calibrate the TDP method. So, sap flow was adopted as representative of coffee plants transpiration for 24-h period. ET and its components were related to the reference evapotranspiration, determined by Penman-Monteith (ETo 1) and Class-A pan (ETo 2) methods. Latent heat of vaporization (LE) represented the major fraction (73 a 80 %) of the available energy (net radiation less soil heat flux) along the months, but a contribution of advective heat flux in dry months must be considered for the observed values. ETc increased from September 2004 to February 2005 (from 2.75 to 4.58 mm d-1), which is reflecting the increase of coffee plants leaf area. From March to May 2005, ETc decreased according to the decrease of the atmospheric demand. In September and October 2005, ETc were greater, respectively, 2.93 and 4.29 mm d-1, than those observed in the same months of 2004 and, again the increase of leaf area was the responsable for these differences. ETc/ETo, defined as a global Kc, was greater when determined with ETo 1 than when determined with ETo 2, increasing with the leaf area.from September 2004 (0.67 with ETo 1 and 0.54 with ETo 2) to January 2005 (1,20 and 1,21). In February Kc decreased to 1.17 (with ETo 1) and 0.73 (with ETo 2), probably as a consequence of the coffee plants stomatal control due to the high atmospheric demand. The contribution of ETrow to ETc varied between 25 % and 31 % for the period September 2004- February 2005, increasing in March and April 2005 (35 % and 40 %). These values were close to those observed for the ratio between the area of soil covered by coffee plants and the total area (rows+interrows). ETlin/ETo changed from 0.20 or 0.16 (using ETo 1 and ETo 2, respectively) in September 2004 to 0.36-0.47 (with ETo 1) or 0.25- 0.49 (with ETo 2) in the other months. Coffee plant transpiration per leaf area unit decresead with the increase of leaf area. T/ETrow changed from 0.72 (February) to 0.46 (April). T/ETo (basal Kc) ranged from 0.13 (with ETo 1) or 0.10 (with ETo 2) in September 2004 to 0.30 (for both ETo 1 or ETo 2) in February, but decreased in April and May 2005, probably reflecting the decrease in the physiological activity of coffee plants.
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Iranawati, Feni. "An assessment of the geographical scale of recurrent gene flow in wild populations of two species of Mekong River carps (Henicorhynchus spp.)." Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/71217/1/Feni_Iranawati_Thesis.pdf.
Full textAbstract:
The Mekong is the most productive river fishery in the world, and such as, the Mekong River Basin (MRB) is very important to very large human populations across the region as a source of revenue (through fishing and marketing of aquatic resources products) and as the major source for local animal protein. Threats to biodiversity in the MRB, either to the fishery sector itself or to other sectors are a major concern, even though currently, fisheries across this region are still very productive. If not managed properly however, fish population declines will cause significant economic impact and affect livelihoods of local people and will have a major impact on food security and nutrition.
Biodiversity declines will undoubtedly affect food security, income and socio-economic status of people in the MRB that depend on aquatic resources. This is an indicator of unsustainable development and hence should be avoided. Genetic diversity (biodiversity) that can be measured using techniques based on DNA markers; refers to variation within and among populations within the same species or reproductive units. In a population, new genetic variation is generated by sexual recombination contributed by individuals with mutations in genes and chromosomes. Over time, populations of a species that are not reproducing together will diverge as differential impacts of selection and genetic drift change their genetic attributes. For mud carp (Henicorhynchus spp.), understanding the status of breeding units in the MRB will be important for their long term persistence, sustainability and for implementing effective management strategies.
Earlier analysis of stock structure in two economically important mud carp species (Henicorhynchus siamensis and H. lobatus) in the MRB completed with mtDNA markers identified a number of populations of both species where gene flow had apparently been interrupted or reduced but applying these data directly to management unit identification is potentially compromised because information was only available about female dispersal patterns. The current study aimed to address this problem and to fully assess the extent of current gene flow (nDNA) and reproductive exchange among selected wild populations of two species of carp (Henicorhynchus spp.) of high economic importance in the MRB using combined mtDNA and nDNA markers. In combination, the data can be used to define effective management units for each species.
In general, nDNA diversity for H. lobatus (with average allelic richness (A) 7.56 and average heterozygosity (Ho) 0.61) was very similar to that identified for H. siamensis (A = 6.81 and Ho = 0.75). Both mud carp species show significant but low FST estimates among populations as a result of lower genetic diversity among sampled populations compared with genetic diversity within populations that may potentially mask any 'real' population structure. Overall, population genetic structure patterns from mtDNA and nDNA in both Henicorhynchus species were largely congruent. Different population structures however, were identified for the two Henicorhynchus species across the same geographical area. Apparent co-similarity in morphology and co-distribution of these two relatively closely related species does not apparently imply parallel evolutionary histories. Differences in each species population structure likely reflect historical drainage rearrangement of the Mekong River. The data indicate that H. siamensis is likely to have occupied the Mekong system for much longer than has H. lobatus in the past. Two divergent stocks were identified for H. lobatus in the MRB below the Khone Falls while a single stock had been evident in the earlier mtDNA study. This suggests that the two Henicorhynchus species may possess different life history traits and that different patterns of gene flow has likely influenced modern genetic structure in these close congeners.
In combination, results of the earlier mtDNA and the current study have implications for effective management of both Henicorhynchus species across the MRB. Currently, both species are essentially treated as a single management unit in this region. This strategy may be appropriate for H. lobatus as a single stock was evident in the main stream of the MRB, but may not be appropriate for H. siamensis as more than a single stock was identified across the same range for this species. Management strategies should consider this difference to conserve overall biodiversity (local discrete populations) and this will include maintaining natural habitat and migration pathways, provision of fish sanctuaries (refuges) and may also require close monitoring of any stock declines, a signal that may require effective recovery strategies.
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Rosado, Bruno Henrique Pimentel. "Ecologia funcional de árvores na Mata Atlântica = o papel de atributos morfológicos, grau de exposição da copa e altitude sobre o uso de água das espécies." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315652.
Full textAbstract:
Orientadores: Marcos Pereira Marinho Aidar, Rafael Silva OliveiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O entendimento de como espécies de plantas utilizam água, requer a caracterização dos fatores que afetam o fluxo de água no contínuo solo-planta-atmosfera (SPA). Desta forma, esta tese reúne trabalhos nos quais investiguei como variações no uso de água de espécies arbóreas na Floresta Atlântica estão relacionadas a atributos morfológicos, grau de exposição da copa (EC) e à variação de fatores abióticos em função da altitude na Mata Atlântica. As altitudes estudadas, 100 e 1000 metros de altitude acima do nível do mar, correspondem às Florestas Ombrófila Densa de Terras Baixas (FODTB) e Montana (FODM). A maior radiação solar (RS) e demanda evaporativa do ar (DPV) associada à menor pressão atmosférica na FODM favoreceriam uma maior transpiração, criando situações de maior vulnerabilidade à variação na disponibilidade hídrica. No entanto, não se pode descartar que mesmo espécies que co-ocorrem em um mesmo ambiente podem apresentar diferentes capacidades de regular o uso de água devido ao papel de atributos morfofisiológicos sobre o SPA. Foram estudados alguns dos componentes do contínuo SPA tais como a densidade de comprimento de raízes finas (DCR) e repelência hídrica foliar (RHF), além de medidas diretas de fluxo de água do xilema. Variações em atributos funcionais e seu reflexo no uso de água das espécies se deram em função da EC e da variação dos fatores abióticos conforme aumento da altitude. Maiores DCR e RHF na FODM; regulação da transpiração noturna na FODM além de menores condutâncias totais associadas a atributos morfológicos indicaram ajustes associados ao uso da água. Estes resultados trazem novas contribuições para o entendimento do funcionamento de floresta tropicais chuvosas ao evidenciar que luz e nutrientes não podem ser considerados como os únicos fatores limitantes destes ambientes
Abstract: Understanding how different plant species and / or functional types use water requires characterization of the factors that affect the continuous soil-plant-atmosphere (SPA). This thesis presents a number of studies in which I investigated how changes in water use of tree species in the Atlantic Forest are related to morphological attributes, crown exposure (CE) and the variation of abiotic factors as a function of altitude in the Atlantic. The altitudes studied, 100 and 1000 meters above sea level, correspond to the lowland ombrophilous dense forest (LODF) and Montane (MODF). Potentially, the higher solar radiation, higher vapor pressure déficit and lower atmospheric pressure at the MODF, would drive higher transpiration rates leading to higher vulnerability to variation in water availability in comparison to the LODF. However, we can not disregard that even co-occurring species may show different abilities to regulate water use due to the role of morpho-physiological traits on the SPA. Were studied components that are part of the continuum SPA such as fine root length density (RLD), which indicates efficiency water absorption, leaf water repellency (LWR) and wood density, besides measurements of sap flow. Variations in functional attributes and its reflection on water use species that have were associated to CE and the variation of abiotic factors according to altitude. Higher RLD and LWR at the MODF; regulation of nighttime transpiration at the MODF and trend of lower total conductance in relation to the LODF indicate adjustments associated with the water use. These results provide important contributions to understanding tropical rain forest functioning and indicate that light and nutrients can not be considered as the only limiting factors at these environments
Doutorado
Biologia Vegetal
Doutor em Biologia Vegetal
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FRANCO, Loris. "Verifica dell’applicabilità del metodo irriguo sub-superficiale su colture agrumicole e ottimizzazione dell’uso della risorsa idrica." Doctoral thesis, Università degli Studi di Palermo, 2020. http://hdl.handle.net/10447/395385.
Full textAbstract:
Gli impianti di subirrigazione (SDI), in relazione alla posizione interrata dei gocciolatori permettono la riduzione dei consumi irrigui, garantendo la possibilità di utilizzo di risorse altrimenti non utilizzabili. Tuttavia, i costi di investimento iniziali risultano maggiori di quelli relativi ai tradizionali impianti di microirrigazione e pertanto, diventano economicamente vantaggiosi, se l'efficienza del sistema viene garantita per periodi di almeno 15-20 anni.
La SDI, inoltre, permette di ottenere valori elevati di efficienza d’uso dell’acqua, spesso superiori al 90%, se associata ad un monitoraggio continuo dello stato idrico del suolo e della pianta e ad una corretta stima delle esigenze della coltura. L’utilizzo congiunto di impianti efficienti e gestione irrigua deficitaria, DI, durante specifiche fasi del ciclo fenologico delle colture può dunque permettere di ridurre ulteriormente i volumi irrigui senza comprometterne il risultato produttivo.
Risulta pertanto necessario individuare sistemi capaci di proteggere gli impianti ed allungarne la vita utile, circostanza questa che si traduce in una protezione degli erogatori da possibili fenomeni di intrusione radicale, oltre che sviluppare dei sistemi di monitoraggio capaci di rilevare in tempo reale e da remoto le variabili del sistema Suolo-Pianta-Atmosfera (SPA), in modo da supportare l’agricoltore nella programmazione dell’irrigazione, anche sulla base di strategie di gestione in condizioni di deficit idrico.
Obiettivo generale del presente studio, come previsto nel progetto di dottorato di ricerca industriale concordato con la società Irritec s.p.a. e con il Dipartimento di Ingegneria rurale ed Agroalimentare dell’Università Politecnica di Valencia, è stato quello di analizzate le principali problematiche ed i possibili sviluppi futuri della subirrigazione.
L’attenzione, nello specifico, è stata focalizzata sulla problematica dell’intrusione radicale e dell’invecchiamento di gocciolatori auto-compensanti installati all’interno di linee gocciolanti interrate a servizio di piante di agrume installate in vaso, oltre che sul risparmio idrico conseguibile in pieno campo attraverso gli impianti di subirrigazione, in assenza ed in presenza di condizioni di deficit idrico, rispetto ai sistemi irrigui a spruzzo tradizionalmente impiegati per la coltura dell’agrume.
Con riferimento al primo aspetto, è stata valutata l’efficacia di cinque principi attivi anti-intrusione radicale, Rame (Cu), Cianammide a due diverse concentrazioni CY1 (1,25%), CY2 (2,5%), e due diversi erbicidi, il Trifluralin (R1) ed il Preventol® (R2), contenuti all’interno di gocciolatori auto-compensanti installati lungo linee gocciolanti integrali prodotte da Irritec s.p.a., al fine di identificarne i possibili effetti sulla crescita dell’apparato radicale ed aereo di un comune portinnesto di agrume (citrange “Carrizo”). Per valutare gli effetti sullo sviluppo radicale, le piante sono state trapiantate all’interno di contenitori suddivisi da un setto che ha permesso la crescita indipendente delle radici nelle due metà del volume radicale irrigate rispettivamente da un gocciolatore contenente un principio attivo e da un gocciolatore di controllo. L’utilizzo di un minirizotrone costruito allo scopo, ha permesso di monitorare la crescita dell’apparato radicale nell’intorno del gocciolatore. Al fine di identificare gli effetti dei diversi principi attivi sullo sviluppo della pianta, alla fine dell’esperimento, è stato effettuato un rilievo distruttivo che ha permesso di valutare il peso delle singole componenti della pianta (radici, fusto, rami e foglie). Al termine dell’esperimento i gocciolatori sono stati sottoposti a prova in modo da valutare la relazione portata-pressione e rilevare le eventuali radici presenti all’interno di ciascun erogatore.
Per quanto concerne il secondo aspetto, invece, su un agrumeto commerciale di circa 30 anni è stata effettuata la riconversione di un impianto irriguo tradizionale a spruzzo con un più moderno impianto in subirrigazione, nel quale è stato effettuato il monitoraggio in tempo reale del sistema Suolo-Pianta-Atmosfera (SPA) per la determinazione dei parametri di programmazione dell’irrigazione, oltre che per valutare gli effetti dell’applicazione di condizioni di deficit idrico controllato (Deficit irrigation, DI) sullo stato idrico della pianta, sui flussi traspirativi e sullo sviluppo vegetativo estivo. L’esperimento ha permesso altresì di di determinare i valori del coefficiente colturale basale Kcb e del coefficiente di stress Ks caratterizzanti le condizioni pedo-climatiche esaminate.
Per valutare l’efficacia, a scala aziendale, di tre dei principi attivi esaminati con le prove in vaso, sono stati realizzati a scala di campo, quattro distinti trattamenti, nei quali sono state installate ali gocciolanti contenenti Rame (Cu) e due diversi erbicidi, il Trifluralin (R1) ed il Preventol® (R2), oltre ad un trattamento di controllo nel quale sono state installate ali gocciolanti senza alcun principio attivo. Metà della superficie è stata gestita in condizioni di DI, mentre l’altra metà in condizioni di rifornimento irriguo ottimale (Full irrigation, FI). Il monitoraggio della funzionalità degli erogatori nel tempo è stato effettuato sulla base di misure globali delle portate erogate da ciascun settore irriguo a parità di pressione di funzionamento dell’impianto.
Il sistema di sensori (“drill & dropTM” ) installati ha permesso, durante il primo anno di studio di monitorare l’irrigazione aziendale gestita secondo le consuetudini locali, oltre che le variabili climatiche. Nel secondo e terzo anno di attività, è stato attivato l’impianto di subirrigazione, implementato il sistema di monitoraggio dello stato idrico della pianta mediante l’installazione di sensori (sap-flow e psicrometri) ed effettuato il monitoraggio del potenziale fogliare mediante camera pressiometrica di Scholander. Inoltre, per valutare gli effetti del deficit idrico sulla vegetazione, sono stati eseguiti rilievi sulla morfologia della chioma, sul LAI, sulla potatura e sulla sviluppo della vegetazione durante il periodo estivo.
Nel corso del triennio di dottorato si è altresì proceduto, utilizzando il banco prova esistente presso il laboratorio di idraulica ed irrigazione dell’Università Politecnica di Valencia, alla caratterizzazione idraulica degli apparecchi erogatori installati in campo.
I vari principi attivi esaminati, destinati ad inibire l’intrusione radicale, non hanno evidenziato effetti negativi diretti sullo sviluppo vegetativo di piante in vaso del portinnesto utilizzato (citrange ‘Carrizo’). L’intrusione radicale si è verificata in presenza di tutti i principi attivi con intensità e fenomenologia variabile; le relativamente migliori performance di protezione dai fenomeni di intrusione radicale sono state ottenute con gli erogatori contenenti Preventol® (R2).
Nonostante i fenomeni di intrusione radicale abbiano interessato, in misura diversa, tutti i modelli di erogatore esaminati, la caratterizzazione idraulica dei gocciolatori effettuata dopo due anni di utilizzo ha permesso di rilevarne la funzionalità residua, che comunque può essere ripristinata con le normali operazioni di pulizia degli impianti.
L’utilizzo delle moderne tecnologie dell’informazione e della comunicazione (ICT), integrate con sensoristica di monitoraggio dello stato idrico del suolo (sensori “drill & dropTM” Sentek), della pianta (sap-flow e psicrometri) e dell’atmosfera (stazione metereologica), ha permesso di creare un ambiente intelligente, capace di trasferire le informazioni in tempo reale attraverso specifiche applicazioni fruibili tramite cellulare o computer.
Il sistema di sensori installati in pieno campo ha permesso di monitorare durante i tre anni di indagine, le dinamiche dell’acqua nel suolo e nella pianta in relazione alla richiesta evapotraspirativa dell’atmosfera.
L’uso della subirrigazione, congiuntamente all’applicazione di strategie di irrigazione deficitaria ha permesso il contenimento dei volumi irrigui, con percentuali medie di risparmio idrico nel biennio 2018-2019 pari rispettivamente al 12,6% e 14,0% per le tesi in assenza di deficit idrico (FI) ed al 43,6 e 35,3 per le tesi mantenute in deficit idrico durante la fase II dello sviluppo vegetativo (DI) rispetto all’irrigazione tradizionale.
Le informazioni acquisite hanno permesso di definire delle soglie di intervento irriguo basate sulla risposta della coltura allo stress idrico. Nello specifico, indipendentemente dal sito di misura, è stato identificato un valore soglia del potenziale idrico predawn, pd, pari a -0,45 MPa, al di sotto del quale si manifestano riduzioni di traspirazione effettiva rispetto alla potenziale. In corrispondenza di tale valore, nelle ore più calde della giornata sono stati misurati valori di stem, compresi tra -1,2 e -1,4 MPa.
Lo studio delle dinamiche traspirative della coltura durante la stagione irrigua, con piante sottoposte a differenti strategie irrigue ha permesso, nei due anni di studio, sia di quantificare il coefficiente colturale basale (Kcb) relativo alla fase intermedia di sviluppo della pianta, che è risultato nei due anni pari a 0,40 (tesi FI), sia il coefficiente di stress (Ks) che, nelle condizioni esaminate, è risultato pari a 0,75 nel 2018 e 0,57nel 2019 (tesi DI).
Lo studio condotto ha permesso quindi di identificare le relazioni tra le varie componenti del sistema SPA e quantificare i parametri utili per la gestione dell’irrigazione in modo automatizzato, oltre che di verificare l’utilizzabilità del metodo irriguo sub-superficiale su colture agrumicole al fine di ottimizzare l’uso della risorsa idrica.
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Korn, Sandra. "Experimentelle Untersuchung der Wasseraufnahme und der hydraulischen Eigenschaften des Wurzelsystems von sechs heimischen Baumarten." Doctoral thesis, [S.l.] : [s.n.], 2004. http://webdoc.sub.gwdg.de/diss/2004/korn/korn.pdf.
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Miranda, Raiane Ferreira de. "Relações hídricas e crescimento do pequizeiro irrigado e adubado." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/6912.
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The souari nut tree, native of the Brazilian Savannah, presents adaptation to the dry season and to poor soils. However, it is believed that in conditions of absence of water deficit and good soil fertility, the plant can develop better than in natural conditions, making commercial cultivation possible. Thus, the present study had as objective to evaluate the water relations and the growth of the souari nut trees in function of irrigation and organic fertilization. For this, 120 souari nut trees (from the 6 to the 8 year-old), spaced at 5.0 x 5.0 m were used in a randomized block experiment with six blocks and 16 plants per block, where four Treatments (IA: Irrigated and fertilizated, IN: Irrigated and no-fertilizated, SA: no-irrigated and fertilizated, SN: no-irrigated and no-fertilizated) in the scheme of subdivided plots. In Nov / 2014 the fertilization was of 12.5 kg of organic composting and 1.0 kg of Yorim, and in Nov / 2015, 5 kg of bovine manure and 2.5 kg of chicken manure per plant. The irrigation system used was a microsprinkler with a emitter per plant (Pressure = 10 mca, q = 43 L h-1, wet radius = 2 m), whereby, during the dry season, an average of 116.95 and 92,24 L plant-1 day-1 were applied in 2015 and 2016, respectively. Water relations evaluation consisted of foliar temperature monitoring (nov/2015 to jun/2016) and transpiration by means of sap flow density (out/2015 to may/2016) in irrigated and non-irrigated plants. As growth variables, the height and perimeter of the stem were evaluated monthly, crown area and root density at 6.5 and 7.1 year-old, respectively. The results showed that when irrigated the leaf temperature of the plant remains below the mean air temperature, regardless of the dry or rainy period, while without irrigation the plant presents in water deficit during the dry season. In dry conditions the mean perspiration of the souari nut tree is 24.09 L plant-1 day-1 and if irrigated on average 42.29 L plant-1 day-1. In spite of water supply and fertilization, the plant does not respond in growth in terms of height and stem perimeter. On the other hand, irrigation influences the canopy area, providing trees with larger canopy areas. When irrigated the souari nut tree presents distance and effective depth of the root system (80%) up to 2.00 m, and in dry conditions the roots are horizontally closer to the plant up to 1.60 m, in depth also concentrate up to 2,00m.
O pequizeiro, nativo do bioma Cerrado, apresenta adaptação à estação seca e a solos pobres. Entretanto, acredita-se que em condições de ausência do déficit hídrico e boa fertilidade do solo, a planta pode se desenvolver melhor que em condições naturais viabilizando seu cultivo comercial. Assim, o presente estudo teve como objetivo avaliar as relações hídricas e o crescimento do pequizeiro em função da irrigação e adubação orgânica. Para isso, foram utilizadas 96 plantas de pequi (do 6º. ao 8º. ano de idade), espaçadas a 5,0 x 5,0 m em experimento conduzido em blocos ao acaso com seis blocos e 16 plantas por bloco, onde foram avaliados quatro tratamentos (I.A.: Irrigação com adubação, I.N.: Irrigação sem adubação, S.A.: Sem irrigação e com adubação e S.N.: Sem irrigação e sem adubação) no esquema de parcelas subdivididas. Em Nov/2014 a adubação consistiu de 2,5 kg de material de compostagem e 1,0 kg de Yorim, e em nov/2015 foram aplicados 5 kg de esterco bovino curtido e 2,5 kg de cama de frango por planta. O sistema de irrigação utilizado foi microaspersão, com um microaspersor por planta (Pressão =10 mca, q = 43 L h-1, raio molhado = 2 m), pelo qual foram aplicados, no período de estiagem, em média 116,95 e 92,24 L planta-1 dia-1 em 2015 e 2016, respectivamente. A avaliação das relações hídricas consistiu no monitoramento da temperatura foliar (nov/2015 a jun/2016) e a transpiração por meio da densidade do fluxo de seiva (out/2015 a mai/2016) nas plantas irrigada e não irrigada. Como variáveis de crescimento avaliou-se a altura e perímetro do caule mensalmente, área da copa e densidade de raízes aos 6,5 e 7,1 anos de idade do pomar, respectivamente. Os resultados mostraram que quando irrigada a temperatura foliar da planta mantém-se abaixo da temperatura média do ar, independentemente do período seco ou chuvoso, enquanto que sem irrigação a planta apresenta-se em déficit hídrico durante a estação seca. Em condições de sequeiro a transpiração média do pequizeiro é de 24,09 L planta-1 dia-1 e se irrigada em média 42,29 L planta-1 dia-1. A despeito do fornecimento de água e adubação, a planta não responde em crescimento em termos de altura e perímetro do caule. Por outro lado, a irrigação influencia na área da copa, proporcionando árvores com áreas de copas maiores. Quando irrigado o pequi apresenta distância e profundidade efetiva do sistema radicular (80%) até 2,00 m, e em condição de sequeiro as raízes apresentam-se horizontalmente mais próximas à planta até 1,60 m e em profundidade concentram-se igualmente, até 2,00m.
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JETTON, AMITY J. "ESTIMATION OF EVAPOTRANSPIRATION OF COTTONWOOD TREES IN THE CIBOLA NATIONAL WILDLIFE REFUGE, CIBOLA, ARIZONA." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1211901752.
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de, la Mota Daniel Francisco Javier. "Water Fluxes in Soil-Pavement Systems: Integrating Trees, Soils and Infrastructure." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/99419.
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In urban areas, trees are often planted in bare soil sidewalk openings (tree pits) which recently are being covered with permeable pavements. Pavements are known to alter soil moisture and temperature, and may have implications for tree growth, root development and depth, drought resilience, and sidewalk lifting. Furthermore, tree pits are often the only unsealed soil surface and are important for water exchange between soil and atmosphere. Therefore, covering tree pits with pavement, even permeable, may have implications for the urban water balance and stormwater management. A better understanding of permeable pavement on tree pavement soil system functioning can inform improved tree pit and street design for greater sustainability of urban environments.
We conducted experiments at two sites in Virginia, USA (Mountains and Coastal Plain) with different climate and soil. At each location, we constructed 24 tree pits in a completely randomized experiment with two factors: paved with resin-bound porous-permeable pavement versus unpaved, and planted with Platanus x acerifolia 'Bloodgood' versus unplanted (n = 6). We measured tree stem diameter, root growth and depth, and soil water content and temperature over two growing seasons. We also monitored tree sap flow one week in June 2017 at the Mountains. In addition, we calibrated and validated a soil water flow model, HYDRUS-1D, to predict soil water distribution for different rooting depths, soil textures and pavement thicknesses.
Trees in paved tree pits grew larger, with stem diameters 29% (Mountains) and 51% (Coastal Plain) greater. Roots developed faster under pavement, possibly due to the increased soil water content and the extended root growing season (14 more days). Tree transpiration was 33% of unpaved and planted pit water outputs, while it was 64% for paved and planted pits. In June 2016, planted pits had decreased root-zone water storage, while unplanted pits showed increased storage. A water balance of the entire experimental site showed overall decreased soil water storage due to tree water extraction becoming the dominant factor. HYDRUS-1D provided overall best results for model validation at 10 cm depth from soil surface (NSE = 0.447 for planted and paved tree pits), compared to 30- and 60 cm depths. HYDRUS-1D simulations with greater pavement thickness resulted in changes in predicted soil water content at the Coastal Plain, with higher values at 10- and 30-cm depths, but lower values at 60-cm depth. At the Mountains, virtually no difference was observed, possibly due to different soil texture (sandy vs clayey).
Tree pits with permeable pavement accelerated tree establishment, but promoted shallower roots, possibly increasing root-pavement conflicts and tree drought susceptibility. Paved tree pits resulted in larger trees, increasing tree transpiration, but reduced soil evaporation compared to unpaved pits. Larger bare soil pits surrounded by permeable pavement might yield the best results to improve urban stormwater retention. Also, HYDRUS 1D was successful at simulating soil water content at 10-cm depth and may be valuable to inform streetscape design and planning.PHD
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Tritschler, Sarah J. "Biogeochemical Processes and Seasonal Effects in Flow-Through Mesocosm Reactors Simulating Constructed Wetlands." Wright State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=wright1198819178.
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Kaennakham, S. "A solution adaptive grid (SAG) for incompressible flows simulations : an attempt towards enhancing SAG algorithm for large eddy simulation (LES)." Thesis, Coventry University, 2010. http://curve.coventry.ac.uk/open/items/c3a447e1-979d-841e-4dec-9b6c2f9c4515/1.
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A study of the use of solution adaptive grid (SAG) method for simulations of incompressible flows is carried out in this work. Both laminar and turbulent types of flows are chosen. Investigation on laminar flow simulation starts with mesh adaptation criteria that are based on strong changes of some selected flow parameters; pressure and velocity components. Three most common laminar types of flows are studied; flow in a circular pipe, flow in a channel with sudden expansion and flow in a cavity with a moving lid. It is found that with the use of SAG, a reduction in both computational grid nodes and CPU time can be obtained when compared to those of fixed grid while satisfactory solutions are also achievable. Nevertheless, the refinement criteria setup procedure reveals inconveniences and requirement for several judgments that have to be defined ‘ad hoc’. This hence, makes the refinement criteria dubious for real engineering applications. For the study of turbulent flows with large eddy simulation (LES) and implicit filtering, examination of literature reveals that the lack of connections between the filter width and a physical scale has made LES somewhat unclosed, i.e. in a physical sense. In addition, it is known that numerical and modelling errors are always combined and it is difficult to study each of them separately making the total error magnitude difficult to control. Since both error types are characterised by the grid size, LES users very often find cases where a finer mesh no longer provides better accuracy. An attempt to address this ‘physical’ enclosure property of LES and its complication to implement/setup in FLUENT begins with the construction of a new refinement variable as a function of the Taylor scale. Then a new SAG algorithm is formed. The requirement to satisfy a condition of the selected subgrid scale (SAG) model, the Smagorinsky model, is taken into consideration to minimize the modeling error. The construction of a new refinement algorithm is also aimed to be the key to studying the interaction between the two types of error and could lead to the means of controlling their total magnitude. The validation in terms of its effectiveness, efficiency and reliability of the algorithm are made based on several criteria corresponding to suitability for practical applications. This includes the simplicity to setup/employ, computational affordability, and the accuracy level. For this, two different turbulent flow types that represent different commonly found turbulent phenomena are chosen; plane free jet and the flow over a circular cylinder. The simulations of the two cases were carried out in two dimensions. It is found that there are two key factors that strongly determine the success of the algorithm. The first factor is the Taylor scale definition, with literature only available for the turbulent plane jet study, for which good level of accuracy is expected. Unfortunately, this is not true for the flow over a circular cylinder, indicating a need for further analytical work. The second encountered difficulty results from limited access to software codes, which makes it impossible to implement the proposed scheme. As a result, the algorithm formulation needs be modified with carful judgment. Nevertheless, overall results are in reasonably good agreement with their corresponding experimental data.
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Lindström, Emelie, and Adam Engström. "Estimations of anthropogenic nutrient flows at the coral reef island Ko Sak, Thailand : A simplified source flow analysis." Thesis, KTH, Industriell ekologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192300.
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High levels of nutrients in tropical coastal areas is a big problem and poses large threats to coral reefs. Therefore this study will focus on nutrient flows from a source perspective. The aim of this study is to identify and quantify the phosphorus and nitrogen emissions from human activities at the island Ko Sak, Thailand. We also investigated possibilities regarding reduction of these emissions. The study was conducted by first identifying the major nutrient emitting human activities during two separate days and then quantifying them one by one. Data was acquired through a combination of personal field observations and literature studies. The following four sources were identified as the most interesting in terms of nutrient emissions: toilet waste on the island, boat sewage, littering (fruit and coconut leftovers) and liquid restaurant waste. The result shows that the sources to the largest phosphorus emissions were littering and toilet waste, while the phosphorus from boat sewage and liquid restaurant waste was lower in comparison. The largest source of nitrogen emissions was toilet waste. In combination with boat sewage they accounted for about 80 % - 90 % of the total nitrogen emissions. The liquid restaurant waste was also in this case very small in comparison and littering completely negligible. The total phosphorus emissions were 514 g/day on April 13 and 438 g/day on May 8 and the total nitrogen emissions were 1750 g/day on April 13 and 1990 g/day on May 8. The two areas identified with largest potential in terms of reducing nutrient emissions were toilet waste and littering due to their relatively large emissions combined with relatively simple flows. Examples of solutions presented is a more controlled toilet waste management system and substituting certain food sold.Höga halter av fosfor- och kväveutsläpp leder till övergödning och är ett stort problem i kustområden. I kustområden finns koraller som är väldigt känsliga organismer som lätt blir påverkade negativt av små förändringar i omgivningen. Detta gör att koraller även är känsliga mot fosfor- och kväveutsläpp. Koraller är vanligtvis väldigt vackra och lockar därför till sig stora mängder turister som vill se på dem. Thailand är ett land som är väldigt beroende av sin turism men med turismen så kommer också ökade miljöproblem, som övergödning. Den här studien syftar till att identifiera och kvantifiera fosfor- och kväveutsläpp från mänskliga aktiviteter vid ön Ko Sak i Thailand. Vi har också undersökt om det finns några möjligheter att minska utsläppen.Studien har gjorts genom att först identifiera fem olika mänskliga aktiviteter som skulle kunna släppa ut fosfor och kväve och sedan kvantifierat dem genom att ställa upp tio stycken ekvationer. Ekvationerna beräknades genom att samla in data från egna observationer på ön och genom litteraturstudier. Observationerna gjordes på två separata dagar. De mänskliga aktiviteter som identifierades var toalettavfall, avloppsvatten från båtar, nedskräpning, flytande avfall från restaurangen och utsläpp vid förbränning i båtmotorer, där förbränning i båtmotorer ansågs som försumbar. Nedskräpningen bestod till största del av rester från frukt och kokosnötter där utsläppen från kokosnötter stod för den överlägset största delen. I alla fall förutom nedskräpning kvantifierades både fosforutsläpp och kväveutsläpp. I nedskräpning antogs dock att alla kväveutsläpp omvandlades till gas och inte hamnar i vattnet vilket gjorde att den inte heller behövde kvantifieras. Källorna till de största fosforutsläppen var nedskräpning och toalettavfall, vilka stod för ungefär 90 % av utsläppen sammanlagt. Fosforinnehållet i avloppsvatten från båtar och flytande avfall från restaurangen var mycket lägre i jämförelse, endast ca 7 % respektive mindre än 1 % av de totala fosforutsläppen. Av kväveutsläppen så var toalettavfall den aktiviteten med störst utsläpp, på mellan 80 % till 90 %. Även i det här fallet så stod flytande avfall från restaurangen för endast runt 1 % av utsläppen. De totala utsläppen var 514 g fosfor/dag den 13 april och 438 g fosfor/dag den 8 maj. Kväveutsläppen blev 1750 g kväve/dag den 13 april och 1990 g kväve/dag den 8 maj. Utsläppen bedöms vara tillräckligt stora för att kunna ha en påverkan på korallerna. De områden som bedömdes ha den största möjligheten för minskade utsläpp var toalettavfall och nedskräpning. Detta på grund av att de hade stora utsläpp men samtidigt relativt simpla flöden. Två exempel på förändringar som föreslås är att införskaffa ett nytt toalettsystem eftersom att det nuvarande kan bedömas som uttjänat och att byta ut försäljningen av kokosnötter till något annat.
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Sedláková, Jitka. "Implementace SAP MM v LSG Asia." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2008. http://www.nusl.cz/ntk/nusl-264895.
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Thesis evaluates implementing of IT product, classifies and compares selected approaches of supply chain management. Classification will be oriented at the usability of the approaches for the evaluation of inventory management, inventory strategies and usability of SAP MM in order to highlight business benefits for LSG Lufthansa Service Holding AG, operating in airline catering business. Concerning size range limitation of the paper, LSG Lufthansa Service Hong Kong Ltd will be analysed followed by defining relevant differences with regards to material flow processes only in LSG Sky Chefs Thailand Ltd.
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Whittier, Jonathan Douglas, and Thomas III Maddock. "A lower San Pedro river basin groundwater flow model." Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 2004. http://hdl.handle.net/10150/615794.
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Water issues in the Lower San Pedro River basin in southeastern Arizona are
becoming increasingly contentious as urban development, agriculture, and mining needs
compete with the needs of the riparian habitat. To better understand the water demands
in this basin, a new groundwater flow model has been created.
First, the conceptual model was produced using various Geographic Information
System (GIS) applications. A new method allocating digital precipitation data to the
smaller drainages within the watershed was used to estimate mountain front recharge.
Well data was gathered from both the United States Geological Survey (USGS) and
Arizona Department of Water Resources (ADWR). Depth to bedrock was interpolated
from an earlier gravity survey of the area. The current extent of riparian vegetation was
determined by recent United States Forest Service aerial photography. GIS shapefiles
were created depicting the data necessary for MODFLOW.
Second, the numerical MODFLOW model was formed using GMS (Groundwater
Modeling System), a graphical user interface for MODFLOW. GMS was used to create
the grid, allocate the information from the shapefiles into MODFLOW input files, create
the MODFLOW numerical model, and calibrate the model. The model results project
potential impacts to the overall sustainability of groundwater within the basin. In the
future, the model will be used as an administrative tool to assess alternative land
management scenarios and their abilities to sustain or improve the riparian habitat along
the San Pedro River.
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Mwansa, Sonny. "Segregation and material flow along low aspect SAG mills." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/5497.
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Includes bibliographical references.The significance of this study is primarily intended to provide better understanding of axial segregation and flow of particles along SAG mills. Additionally, the current SAG mill models developed using "short" Australian and North American style mills exposes inaccuracies when applied to predict the performance of "long" mills. Thus the results of this study are expected to be useful for improving modelling of long SAG mills. Several studies of radial and axial segregation in tumbling horizontal devices at laboratory-scale and a few on pilot-scale have been conducted in the past by various researchers. Recently, industrial-scale studies of axial segregation in kilns and dry milling, particularly in the cement industry have also been conducted. However, there seems to be no work reported and cited in the literature on axial segregation studies along SAG mills. Thus the lack of previous segregation research along SAG mills has exposed a knowledge gap in the subject.
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Ferreira, Ricardo João Dias Fernandes Lopes. "Equity Research - Sport Lisboa e Benfica - Futebol, SAD." Master's thesis, Instituto Superior de Economia e Gestão, 2017. http://hdl.handle.net/10400.5/14474.
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Mestrado em FinançasO presente estudo efetua uma análise detalhada da Sport Lisboa e Benfica SAD (SLBEN). A necessidade da realização deste estudo prende-se com o constante crescimento da Industria do futebol, com a hegemonia desportiva alcançada pelo Sport Lisboa e Benfica e ainda com o objetivo traçado pelos Diretores da empresa que pretendem efetuar uma grande mudança na sua estrutura de capital. Todo o estudo segue as normas e recomendações do CFA Institute. Para a realização deste estudo, foi tida em consideração toda a informação disponível à data de 7 de Setembro de 2017, sendo que quaisquer informações ou eventos ligados à Benfica SAD, ou ao mercado envolvente após essa data não tem qualquer impacto ou relevância para os resultados obtidos. Foram efetuadas duas abordagens para o cálculo do preço-alvo: uma avaliação relativa, de acordo com o método dos múltiplos e uma avaliação absoluta, tendo por base o método dos Fluxos de Caixa Descontados. De referir que por ambas as abordagens o preço-alvo atingido foi de €1.84, representado um potencial de valorização de 101.3%, uma vez que à data do levantamento do preço histórico da ação, encontrava-se valorizada a €0.92. Com base nesta informação a recomendação para as ações do SLBEN é de compra. De referir ainda que é assumido um risco médio uma vez que se trata de uma industria volátil em que os resultados desportivos tem alguma influencia nos resultados financeiros, bem como a baixa liquidez das ações referidas.
The present study makes a detailed analysis of Sport Lisboa and Benfica SAD (SLBEN). The need to carry out this study is related to the constant growth of the Football Industry, with the sporting hegemony achieved by Sport Lisboa and Benfica and also with the objective drawn by the Directors of the company that intend to make a major change in its capital structure. The entire study follows the standards and recommendations of the CFA Institute. In order to carry out this study, all information available as of September 7, 2017 has been taken into account, and any information or events related to Benfica SAD or to the surrounding market after this date has no impact or relevance to the results obtained. Two approaches were used to calculate the target price: a relative valuation according to the multiples method and an absolute valuation based on the Discounted Cash Flow method. It should be noted that for both approaches the target price reached was €1.84, representing a potential appreciation of 101.3%, since at the date of the historical price of the share, it was valued at €0.92. Based on this information the recommendation for the shares of SLBEN is to purchase. It should also be noted that an average risk is assumed since it is a volatile industry in which sports results have some influence on the financial results as well as the low liquidity of the referred actions.
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Grossiord, Charlotte. "Impact of tree species diversity on water and carbon relations in European forests." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0155/document.
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La biodiversité favorise un grand nombre de fonctions et services écosystémiques des écosystèmes forestiers tels que la production de bois ou la résistance aux attaques d’insectes et aux maladies. Cependant l’impact de la diversité sur l’acquisition et l’utilisation de l’eau et du carbone reste largement méconnu dans ces écosystèmes. De plus, dans le contexte actuel de changement climatique, l’influence de la diversité sur la réponse des écosystèmes forestiers à des événements climatiques extrêmes tels que la sécheresse reste à étudier. L’objectif de ce travail est donc de déterminer l’impact de la diversité en espèces d’arbre sur d’importantes fonctions du cycle de l’eau et du carbone telles que la transpiration, la composition isotopique du carbone ou la profondeur d’extraction de l’eau à l’échelle de l’arbre et de l’écosystème sous des conditions contrastées dedisponibilité en eau du sol. Ce travail a été réalisé dans le cadre du projet FunDivEUROPE sur un réseau de parcelles forestières ainsi que dans des plantations expérimentales le long d’un gradient Nord-Sud en Europe afin de couvrir une importante gamme de conditions climatiques. Nos travaux ont montré une importante variabilité de la réponse à la diversité à l’échelle de l’arbre et de l’écosystème en termes de relations hydriques et carbonées à travers l’Europe. La diversité en espèces ne semble pas influencer les relations hydriques et carbonées des espèces et des écosystèmes forestiers dans des conditions non limitantes de disponibilité en eau. Cependant, un fort effet de la diversité a été observé en conditions de sécheresse pour certains types forestiers. A partir de ces résultats, je discute des mécanismes d’interaction entre espèces qui peuvent expliquer les effets observés. Nos données ont montré que l’influence de la diversité en espèces est fortement dépendante du contexte et peut êtremodifiée par les conditions environnementales locales et les conditions climatiques. En terme de gestion forestière, je suggère que pour certaines régions en Europe, promouvoir la diversité en espèces ainsi que contrôler la densité des parcelles doit être recommandé afin d’adapter les écosystèmes forestiers aux futures conditions climatiquesBiodiversity is known to support and boost a wide range of forest ecosystem functions and services like productivity and resistance against insect pests and diseases. However, whether tree species diversity also promotes water and carbon acquisition and use in forest ecosystems is still unclear. Furthermore, in the current context of global warming, information on how tree species diversity can influence the response of forest ecosystems to extreme climatic events such as drought are urgently needed. In this framework, the objective of my PhD thesis was to determine how tree species diversity influences important functions of the water and carbon cycle including transpiration, carbon isotope composition and water extraction depth at the tree- and ecosystem-Scale under contrasting soil water conditions. My work was conducted within the FunDivEUROPE project in a network of permanent forest stands and tree plantations across a North-South gradient in Europecovering a wide range of climatic conditions. I found considerable variability among species or forest types in the response of transpiration and carbon isotope composition at the tree- and ecosystem-Scale across Europe. Species diversity did not affect the water and carbon relations of tree species and forest ecosystems under non-Limiting soil water conditions. However, a strong effect of species diversity was observed under drought conditions in some forest types. Based on these data, I discuss the potential mechanisms of species interactions that may explain the observed patterns. I also point out that the influence of species diversity is highly context-Dependent, and changes with local environmental and climatic conditions. In terms of forest management applications, I suggest that, at least in some regions, controlling for tree species diversity along with stand density and total basal area could be recommended to help forests adapt to drier conditions
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Oikonomou, Emmanouil Konstantiou. "Stationary phase internal waves generated by flow along sloping topography." Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242690.
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Walker, T. Owens. "Traffic-adaptive, flow-specific medium access for wireless networks." Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/dissert/2009/Sep/09Sep_Walker_PhD.pdf.
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Dissertation (Ph.D. in Electrical Engineering)--Naval Postgraduate School, September 2009.Dissertation Advisor(s): Tummala, Murali ; McEachen, John. "September 2009." Description based on title screen as viewed on November 5, 2009. Author(s) subject terms: Flow-specific; Traffic-adaptive; Cross layer; Medium access control; Wireless; Energy-efficiency; Preamble sampling; Networked satellite systems. Includes bibliographical references (p. 119-213). Also available in print.
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Rainha, Bernardo Damasceno Pina. "Equity research - Sporting Clube de Portugal – Futebol, SAD." Master's thesis, Instituto Superior de Economia e Gestão, 2018. http://hdl.handle.net/10400.5/17636.
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Mestrado em Contabilidade, Fiscalidade e Finanças EmpresariaisO seguinte trabalho tem como objetivo a avaliação das ações da Sporting Clube de Portugal - Futebol, SAD (Sporting SAD). Para tal, foi feito um estudo da indústria do futebol, um segmento da indústria desportiva que tem vindo a atrair cada vez mais adeptos/espectadores assim como a gerar mais receitas. No entanto, quanto ao caso em estudo, a Sporting SAD não tem apresentado uma estrutura de capital sólida, estando muito dependente tanto dos resultados desportivos como da venda de jogadores para atingir bons resultados financeiros. Esta avaliação foi realizada à data 30/06/2017. De referir que quaisquer informações ou acontecimentos relacionados com a Sporting SAD ou com o sector após maio de 2018 não foram considerados no nosso estudo. Esta avaliação foi feita seguindo o método Discounted Cash Flow tendo-se optado pela abordagem dos Free Cash Flow to Firm (FCFF). De forma a obter uma recomendação mais robusta e sustentada, a avaliação foi complementada com uma metodologia de avaliação relativa, o Método dos Múltiplos. O resultado obtido foi a subvalorização das ações uma vez que o preço histórico da ação é de 0,62€ e o target price obtido foi de 0,92€ (FCFF), apresentando um upside potencial de 47,96% que leva a uma recomendação final de compra de ações da Sporting SAD. Este resultado foi ainda reforçado pela avaliação relativa.
The following thesis' main goal is to make a valuation of Sporting Clube de Portugal - Futebol, SAD (Sporting SAD). In that sense, the football industry was studied, a sports' industry segment that has been attracting more people/spectators over time as well as generating more revenue. However, Sporting SAD does not present a solid capital structure, being very dependent on both the sports results and players' sales to achieve good financial results. This valuation was made on the 30th of June, 2018. It should be referred that any information or events related to Sporting SAD or the sector May of 2018 have no influence on the results obtained. This valuation was made following the Discounted Cash Flow method and the Free Cash Flow to Firm (FCFF) approach was chosen. To obtain a more robust and sustained recommendation, the valuation was complemented by a relative valuation methodology, the Market Approach. The result obtained was that Sporting SAD shares are undervaluated since the historical price of the share was 0,62€ and the target price was 0,92€ (FCFF), presenting a potential upside of 47,96% that leads to a final recommendation to buy Sporting SAD's shares. This result was further reinforced by the relative valuation.
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Baillie, Matthew Nelson. "Quantifying baseflow inputs to the San Pedro River a geochemical approach /." Thesis, The University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2005_019_sip1_w.pdf&type=application/pdf.
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Maxfield, Sandra Leigh 1956. "Design of wellfield and recharge operations in forebay area of San Bernardino basin, California." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277994.
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East Valley Water District is located in San Bernardino, California which is approximately 50 miles east of Los Angeles. In order to meet future water demands, East Valley Water District plans to increase recharge activities in the forebay area of the San Bernardino groundwater basin and expand wellfield operations immediately downgradient. Three possible recharge and wellfield designs were under consideration with annual recharge rates increasing 10,000 to 20,000 acre-feet/year in the Santa Ana spreading basins. Approximately four to five new production wells pumping an equal quantity of groundwater have been proposed. A two-dimensional finite element groundwater flow model was constructed and calibrated to reproduce historical water level data for the year 1945. They calibrated model was applied to simulate the hydrologic effects of each of the three designs over a ten-year period.
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Cordero, Samuel F. "Investigation of performance improvements including application of inlet guide vanes to a cross-flow fan." Thesis, Monterey, Calif. : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep_Cordero.pdf.
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Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Hobson, Garth V. ; Gannon, Anthony. "September 2009." Author(s) subject terms: Fan, cross-flow, crossflow, inlet guide vanes, thrust vectoring, vertical take off. Description based on title screen as viewed on Nov. 5, 2009. Includes bibliographical references (p. 95). Also available in print.