Rozprawy doktorskie: „Salinity control”

1

Gudmundsson, Kristinn. "Control of salinity intrusion caused by sea level rise". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-11242009-020133/.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

2

Foroozanfar, Maryam. "Genetic control of tolerance to salinity in Medicago truncatula". Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0035/document.

Pełny tekst źródła

Streszczenie:

Parmi les contraintes abiotiques la salinité est considérée comme un problème majeur, qui affecte le fonctionnement des plantes, en particulier leur croissance et leur rendement. Afin d’étudier le contrôle génétique de la tolérance à la salinité chez Medicago truncatula, plante modèle de la famille des légumineuses, deux expérimentations ont été réalisées. La première expérimentation visait à étudier l’effet de la contrainte saline sur différents paramètres morpho-physiologiques pour un panel de génotypes de M. truncatula afin de déterminer les traits de phénotypage pour la tolérance à la salinité. Les génotypes A17, TN1.11, DZA315.16, A20, TN1.12 et F83005.5 ont été sélectionnés parmi des lignées originaires de différents pays méditerranéens, qui ont été déjà séquencées (http://www1.montpellierinra.fr/BRC-MTR/mauguio/mauguio.php). Les génotypes ont été étudiés sous 6 traitements salins (0, 30, 60, 90,120 et 150 mM NaCl) dans un essai factoriel sous forme de blocs complets aléatoires en trois répétitions. L’analyse de la variance montre des différences significatives entre les niveaux de salinité et une interaction entre les génotypes et les traitements salins concernant la plupart des caractères étudiés. Le génotype « DZA315.16 » présente les valeurs les plus importantes concernant les effets principaux pour les caractères morphologiques alors que « TN1.11 » présente les valeurs les plus faibles. La projection verticale de la surface foliaire de la plante (Leaf Area=LA), significativement corrélée à la biomasse des plantes, apparaît comme un trait d’intérêt pour le phénotypage de la tolérance à la salinité. La concentration saline la mieux adaptée pour démontrer les différences parmi les lignes étudiées se situe entre 90 et 120 mM NaCl. Le génotype « TN1.11 » contrairement à « DZA315.16 » et à « Jemalong-A17 » présente un maintien de la surface foliaire de la plante en réponse à la salinité. Pour la deuxième expérimentation, une population de cent lignées recombinantes (Recombinant Inbred Lines=RILs) produite par le croisement entre « TN1.11 » et « Jemalong-A17 » a été retenue pour l’analyse du contrôle génétique de la tolérance à la salinité. Les RILs ont été développés par la méthode de descendant mono graines (Single Seed descent= SSD) jusqu’ à la génération F6 à l’INP-ENSAT, France. Le plan d’experimentation est « Spli plots » , sous forme de blocs randomisés avec trois répétitions et deux conditions : traitement salin (100 mM NaCl) et témoin (eau). L’expérience a été menée pour déterminer la variabilité génétique et pour identifier les QTLs contrôlant les caractères morphologiques et physiologiques chez la population des lignées recombinantes (RILs). L’analyse de la variance a montré une large variation génétique et une ségrégation transgressive pour les caractères étudiés. La différence entre la moyenne des RILs et la moyenne de leurs parents n’est pas significative concernant tous les caractères étudiés dans les deux conditions, ce qui montre que les RILs utilisées dans notre expérimentation sont représentatives de toutes les lignées recombinantes possibles du croisement « TN1.11 x Jemalong-A17 ». 21 QTLs ont été détectés dans la condition témoin et 19 QTLs ont été identifiés sous contrainte saline (100 mM NaCl). Le pourcentage de la variance phénotypique expliqué par les QTLs varie entre 4.60% et 23.01%. Certains de ces QTLs sont spécifiques à la condition saline, ce qui démontre l’existence du contrôle génétique de la tolérance à la salinité chez M. truncatula ; tandis que les autres ne sont pas spécifiques et contrôlent un même caractère dans les deux conditions. Des QTLs superposés concernant différents caractères ont été aussi observés. Les résultats fournissent des informations importantes en vue de futures analyses fonctionnelles de la tolérance à la salinité chez M.truncatula et pour d’autres espèces voisines
Among abiotic stresses salinity is considered as a serious problem affecting plant functions especially growth and yield. In order to study the genetic control of salt stress in the model legume Medicago truncatula, two experiments were performed. The first experiment was conducted to study the effect of salt stress on some morpho-physiological parameters in M. truncatula genotypes and to determine the eventual use of some traits as tolerance criteria. Genotypes including A17, TN1.11, DZA315.16, A20, TN1.12 and F83005.5 are selected through a sequenced lines collection (http://www1.montpellierinra.fr/BRC-MTR/mauguio/mauguio.php) which are originated from different Mediterranean countries. Genotypes were studied under 6 salinity treatments (0, 30, 60, 90,120 and 150 mM NaCl) in a factorial design based on randomized complete blocks with three replications. Analysis of variance show significant differences among genotypes, salinity levels and interaction between genotypes and salt treatments for most of studied traits. “DZA315.16” genotype presents the highest main effect values for morphological traits whereas”TN1.11” has low values. Vertically projected leaf area (LA); show the highest variability through all studied salt concentrations. The best concentration to find differences between parental lines is 90 to 120 mM Nacl. A segregating population of recombinant inbred lines (100 RILs) of M.truncatula derived from a cross between TN1.11 and Jemalong-A17 was used for the second experiment. RILs were developed by single-seed descent until F6 generation at the INP-ENSAT, France. The experiment was undertaken to determine the genetic variability and to identify QTLs controlling several traits related to plant growth and physiology, in the population of recombinant inbred lines (RILs). Analyses of variance showed a large genetic variation and transgressive segregation for the traits studied. The difference between the mean of RILs and the mean of their parents was not significant for all of the traits in both conditions, showing that the RILs used in our experiment are representative of the possible recombinant lines from the cross TN1.11 x A17. A total of 21 QTLs were detected under control and 19 QTLs were identified under 100mM salt stress conditions. The percentage of total phenotypic variance explained by the QTLs ranged from 4.60% to 23.01%. Some of the QTLs were specific for one condition, demonstrating that the genetic control of a traits differed under control and salt stress conditions. Some others are non-specific and control a trait in both conditions. Overlapping QTLs for different traits were also observed. The results provide important information for further functional analysis of salt tolerance in M. truncatula

Style APA, Harvard, Vancouver, ISO itp.

3

Asghar, Muhammad Nadeem. "Computer simulation of salinity control by means of an evaporative sink". Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318173.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

4

Barr, N. F. "Salinity control, water reform and structural adjustment : the Tragowel Plains Irrigation District /". Connect to thesis, 1999. http://eprints.unimelb.edu.au/archive/00000230/l.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

5

Turkmen, Muserref. "Sulfur-containing odorants and the effects of high salinity in anaerobically digested biosolids". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 224 p, 2007. http://proquest.umi.com/pqdweb?did=1257807571&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

6

Graham, Tennille. "Economics of protecting road infrastructure from dryland salinity in Western Australia". University of Western Australia. School of Agricultural and Resource Economics, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0207.

Pełny tekst źródła

Streszczenie:

[Truncated abstract] The salinisation of agricultural land, urban infrastructure and natural habitat is a serious and increasing problem in southern Australia. Government funding has been allocated to the problem to attempt to reduce substantial costs associated with degradation of agricultural and non-agricultural assets. Nevertheless, Government funding has been small relative to the size of the problem and therefore expenditure needs to be carefully targeted to interventions that will achieve the greatest net benefits. For intervention to be justified, the level of salinity resulting from private landholder decisions must exceed the level that is optimal from the point of view of society as a whole, and the costs of government intervention must be less than the benefits gained by society. This study aims to identify situations when government intervention is justified to manage dryland salinity that threatens to affect road infrastructure (a public asset). A key gap in the environmental economics literature is research that considers dryland salinity as a pollution that has off-site impacts on public assets. This research developed two hydrological/economic models to achieve this objective. The first was a simple economic model representing external costs from dryland salinity. This model was used to identify those variables that have the biggest impact on the net-benefits possible from government intervention. The second model was a combined hydro/economic model that represents the external costs from dryland salinity on road infrastructure. The hydrological component of the model applied the method of metamodelling to simplify a complex, simulation model to equations that could be easily included in the economic model. The key variables that have the biggest impact on net-benefits of dryland salinity mitigation were the value of the off-site asset and the time lag before the onset of dryland salinity in the absence of intervention. ... In the case study of dryland salinity management in the Date Creek subcatchment of Western Australia, the economics of vegetation-based and engineering strategies were investigated for road infrastructure. In general, the engineering strategies were more economically beneficial than vegetation-based strategies. In the case-study catchment, the cost of dryland salinity affecting roads was low relative to the cost to agricultural land. Nevertheless, some additional change in land management to reduce impacts on roads (beyond the changes justified by agricultural land alone) was found to be optimal in some cases. Reinforcing the results from the simple model, a key factor influencing the economics of dryland salinity management was the urgency of the problem. If costs from dryland salinity were not expected to occur until 30 years or more, the optimal response in the short-term was to do nothing. Overall, the study highlights the need for governments to undertake comprehensive and case-specific analysis before committing resources to the management of dryland salinity affecting roads. There were many scenarios in the modelling analysis where the benefits of interventions would not be sufficient to justify action.

Style APA, Harvard, Vancouver, ISO itp.

7

Berns, Donna M. "Physiological Responses of Thalassia testudinum and Ruppia maritima to Experimental Salinity Levels". [Tampa, Fla.] : University of South Florida, 2003. http://purl.fcla.edu/fcla/etd/SFE0000198.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

8

Israelsen, Karl R. "Herbicide, Salinity, and Flooding Tolerance of Foxtail Barley (Hordeum jubatum L.) and Desirable Pasture Grasses". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/519.

Pełny tekst źródła

Streszczenie:

Research trials performed in the greenhouse compared the tolerance and response of Hordeum jubatum and desirable pasture grass species to herbicides, salinity, and flooding. Desirable grass species used in this study included: `Fawn' tall fescue (Festuca arundinaceae), `Garrison' creeping foxtail (Alopecurus arundinaceus), `Palaton' reed canarygrass (Phalaris arundinacea), `Climax' timothy (Phleum pratense), `Alkar' tall wheatgrass (Thinopyrum ponticum), `Potomac' orchardgrass (Dactylis glomerata), and `Mustang' altai wildrye (Leymus angustus). Tolerance to herbicides, salinity, and flooding varied significantly among grass species. Herbicide tolerance was tested using four herbicides at five rates each. The herbicides used were imazapic (Plateau), propoxycarbazone (Olympus), sulfosulfuron (Outrider), and flucarbazone (Everest) at rates of 0, 10, 25, 50, 100, and 200 g ha-1. Foxtail barley was least tolerant of sulfosulfuron and propoxycarbazone. Tall fescue, creeping foxtail, and reed canarygrass were susceptible to all the herbicides tested. Timothy and foxtail barley were moderately tolerant while tall wheatgrass exhibited the greatest tolerance to flucarbazone. Orchardgrass was most tolerant to propoxycarbazone. Salinity tolerance was determined by exposing grasses to increasing electrical conductivity (EC) over time. Reed canarygrass and timothy were most susceptible to salinity. Orchardgrass, creeping foxtail, and tall fescue were moderately tolerant of salinity. Foxtail barley, altai wildrye, and tall wheatgrass exhibited the highest tolerances to salinity, and continued to persist at the highest EC levels tested. Flooding tolerance was determined by flooding grasses in 18 cm of water for 2, 4, 6, and 8 weeks. Grasses that were able to extend above the water surface survived, whereas plants that failed to extend beyond the water surface experienced higher mortality rates.

Style APA, Harvard, Vancouver, ISO itp.

9

Bernatzeder, Andrea Katinka. "Salinity induced physiological responses in juvenile dusky kob, Argyrosomus japonicus (Sciaenidae)". Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005163.

Pełny tekst źródła

Streszczenie:

Fisheries management regulations for dusky kob Argyrosomus japonicus, an important commercial and recreational fisheries species, have failed and the stock is considered collapsed. It is important to take an ecosystems approach to management which includes understanding the effect of environmental factors on recruitment, abundance and distribution. The distribution of early juveniles (20-150 mm TL) in the wild appears to be restricted to the upper reaches of estuaries at salinities below 5 psu. Food availability could not explain the distribution of early juveniles. The aim of this study was to investigate the role of salinity on the distribution of early juvenile dusky kob (<150 mm TL) by examining physiological responses of juveniles exposed to a range of salinities under laboratory conditions. The hypothesis was that the physiological functioning of early juveniles would be optimised at the reduced salinities which they naturally occur at. The objectives of this study were to investigate the effect of salinity on: i) plasma osmolality; ii) growth, food conversion ratio and condition factor; and iii) gill histology with emphasis on chloride cell size and number. A preliminary study was undertaken to determine whether the use of 2-phenoxyethanol had an effect on plasma osmolality. Juveniles pithed prior to blood sampling were used as the control. Plasma osmolality was not affected by exposure or duration of exposure (2, 4, 6, 8, 10 min) to 2-phenoxyethanol. The ability of teleosts to regulate plasma osmolality over a wide range of salinities indicates their degree of ‘physiological euryhalinity’. Plasma osmolality of juveniles exposed to 5, 12 and 35 psu was measured every two weeks over a total of six weeks. Although juveniles were able to regulate plasma osmolality over the duration of the experiment, plasma osmolality at 5 and 12 psu was significantly lower than in fish maintained at 35 psu. Growth is used as an indicator of the relative energy used for osmoregulation at different salinities, as the energy used for osmoregulation becomes unavailable for growth. A nineweek growth experiment was conducted on juveniles exposed to 5, 12 and 35 psu. Juveniles grew and survived at all three salinities. However, growth of juveniles at 5 psu was significantly lower than at 12 and 35 psu. Other than a significantly greater weight gain at 35 psu relative to 12 psu, there was no significant difference in specific growth and length gain between juveniles at 12 and 35 psu. Food conversion ratio and condition factor at 12 and 35 psu were not significantly different, but food conversion ratio and condition factor at 5 psu was significantly greater and lower than at 35 psu respectively. In fish, gills are considered the major organ involved in osmoregulation. Within the gills, chloride cells are the predominant site of ion exchange which is driven by the Na⁺, K⁺- ATPase enzyme. Gill samples of juveniles exposed to 5, 12 and 35 psu for six weeks were examined histologically using light microscopy. Chloride cells of juveniles maintained at 5 psu were significantly more abundant than in juveniles at 12 and 35 psu. Chloride cells of juveniles at 5 psu were significantly larger than in juveniles kept at 12 psu, but not significantly different to those of juveniles kept at 35 psu. The ability of the juvenile fish to regulate plasma osmolality indicates that they are 'physiologically euryhaline', but the reduced growth and proliferation of chloride cells at 5 psu suggests that energy expenditure for osmoregulation is increased at hypoosmotic salinities. Salinity induced physiological responses could therefore not explain the natural distribution of early juvenile dusky kob and it is proposed that other environmental factors (e.g. temperature) are also important. It is also hypothesised that the high conductivity of an estuary in South Africa, to which our understanding is limited, may negate the effect of reduced salinity. Although freshwater input into estuaries is an important factor, further investigations to explain the distribution and abundance of early juveniles is required to make management recommendations. Dusky kob is also becoming an increasingly popular aquaculture species in South Africa. In this regard, early juvenile dusky kob can be grown at salinities as low as 12 psu without negatively affecting growth and production.

Style APA, Harvard, Vancouver, ISO itp.

10

Slaughter, Andrew Robert. "The refinement of protective salinity guidelines for South African freshwater resources". Thesis, Rhodes University, 2005. http://eprints.ru.ac.za/159/.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

11

Bell, Lindsay William. "Prospects of Dorycnium species to increase water use in agricultural systems of southern Australia /". Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2006.0033.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

12

Schroeder, Robin L. "Exchange flows in an urban water body: Bayou St. John responses to the removal of flood control structures, future water elevation control, and water quality". ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/1394.

Pełny tekst źródła

Streszczenie:

Bayou St. John, an urban water body extending south from Lake Pontchartrain, has two anthropogenic structures that regulate flow from the Lake . The City of New Orleans has plans to remove the inner control structure to improve water quality. Field and numerical methods used in this study show removing this structure increased water elevations throughout the Bayou but resulted in lower water elevation signal amplitudes that caused a lower tidal flow exchange from north to south. Bulk Richardson numbers showed mixing was inversely related to flow and the Bayou generally remains stratified. Resuspension of contaminated sediment could negatively impact the local ecology but predicted shear stress values did not reach a critical value (0.1 N/m2) for resuspension. Removal of the waterfall structure will benefit Bayou St. John by decreasing energy losses from the Lake, however a more pronounced tidal signal from Lake Pontchartrain is required to flush the Bayou.

Style APA, Harvard, Vancouver, ISO itp.

13

Long, Amy K. "Control of lysogeny in marine bacteria : studies with phiHSIC and natural populations". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001737.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Lerotholi, Sekhonyana. "The role of salinity as an abiotic driver of ecological condition in a rural agricultural catchment". Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1005528.

Pełny tekst źródła

Streszczenie:

The Kat River is an agricultural catchment that drains salt rich geology. Potential salinity impacts on ecological condition of the river were investigated. Monthly salt concentrations and flow discharges were monitored at ten sites along the Kat River below the Kat Dam. Monthly salt loads were computed to relate salinity to land use and ionic data used to assess the toxicity of major salts using the TIMS model. Concentration duration curves for sodium chloride were derived from flow concentration relationships, representing sodium chloride concentrations to which the aquatic ecosystem had been exposed. The ecological condition was assessed at nineteen sites using SASS5 biotic index over four seasons. Finally, the modelled instream salt concentrations and bioasessments were evaluated in terms of the modelled level of species protection afforded at different salt concentrations. Species Sensitivity Distributions (SSDs) were used for this exercise. There was a general downstream increase in salinity with the minimum concentrations recorded at the Fairbain tributary (84 mg/L) and maximum levels at the sewage outfall in Fort Beaufort (1222 mg/L). There was evidence that citrus irrigation upstream of Fort Beaufort increased salinisation. Sodium chloride, and to a lesser extent magnesium sulphate, were the dominant salts in the Kat River catchment, with the latter being more toxic. However these had little or no impact on the aquatic ecosystem. Flow-derived sodium chloride concentrations showed that both the Balfour and Blinkwater tributaries were in a fair/ poor condition. However with regard to ecological condition, it was demonstrated that the river is generally in a good state except for the Blinkwater River and the lower catchment. Degraded habitat condition at the Blinkwater was responsible for poor ecological condition. Integrating SSD derived classes, sodium chloride classes and ecological condition indicated that sodium chloride is a driver of ecological condition at the sewage treatment works and the subsequent site (only two of nineteen biomonitoring sites).

Style APA, Harvard, Vancouver, ISO itp.

15

Doole, Graeme John. "Value of perennial pasture phases in dryland agricultural systems of the eastern-central wheat belt of Western Australia". University of Western Australia. School of Agricultural and Resource Economics, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0213.

Pełny tekst źródła

Streszczenie:

Over the past thirty years, price relativities and technological development have motivated an increase in the area of land allocated to cropping, as opposed to pasture production, throughout the central wheat belt of Western Australia. Nevertheless, reducing the proportion of pasture in these rotations has challenged the future productivity of farming systems in this area. First, the frequent application of selective herbicides for weed control in extended cropping rotations has promoted the development of herbicide resistance in a number of major agricultural weeds. Second, the primary use of annual plants has promoted the development of soil salinisation by allowing a significant proportion of rainfall to recharge saline water tables. The inclusion of perennial pasture phases between extended periods of cropping may mitigate or delay these constraints to production through (a) allowing the use of costeffective forms of non-selective weed control, and (b) through creating a buffer of dry soil that absorbs leakage occurring beneath subsequent crops. This study consequently explores the value of including perennial pasture phases in dryland agricultural systems in the eastern-central wheat belt of Western Australia, accounting for benefits related to herbicide resistance and water table management. A novel computational algorithm for the solution of multiple-phase optimal control problems is developed and used to conduct a conceptual analysis of the value of lucerne (Medicago sativa L.) pasture for managing annual ryegrass (Lolium rigidum Gaudin), the primary weed in wheat belt cropping systems. The competitiveness and fecundity of annual ryegrass provide strong economic incentives to maintain a low weed population, irrespective of herbicide-resistance status. Consequently, the ineffectiveness of selective herbicides primarily reduces the profitability of cropping by motivating the adoption of more costly non-selective forms of weed control. The inclusion of lucerne in land-use rotations is only optimal in the presence of severe herbicide resistance given (a) the low efficiency of alternative weed-management practices available during the pasture phase, relative to selective-herbicide application; (b) the significant cost of establishing this perennial pasture; and (c) the high relative profitability of cereal production in the absence of resistance. The value of lucerne, relative to annual pastures, for weed management is explored in greater detail through the use of compressed annealing to optimise a sophisticated simulation model. The profitability of candidate rotations is also manipulated to account for the long-term production losses accruing to the recharge of saline groundwaters that occurs beneath them. Sequences incorporating lucerne are only more profitable than those that include annual pasture at the standard set of parameter values if (a) annual ryegrass is resistant to all selective herbicides, (b) the water table is so shallow (approximately less than 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, or (c) sheep production is highly profitable. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost. Consistent with intuition, these benefits are reinforced by lower discount rates and higher rates of leakage occurring beneath annual-based systems. Formulation of an effective communication strategy to report these results to producers is justified given the complexity involved in determining the true magnitude of these intertemporal benefits through alternative means, such as field trials.

Style APA, Harvard, Vancouver, ISO itp.

16

Bell, Lindsay William. "Prospects of Dorycnium species to increase water use in agricultural systems of southern Australia". University of Western Australia. School of Plant Biology, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0033.

Pełny tekst źródła

Streszczenie:

[Truncated abstract] Dryland salinity is a major environmental challenge facing agriculture in Australia. One option to manage dryland salinity is the use of perennial forages that increase water use of agricultural systems. However, the current array of perennial forages is limited. Forage species that satisfy the range of climatic and edaphic environments, and production systems, in southern Australia are needed (Chapter 1). In particular, low rainfall regions lack options other than lucerne (Medicago sativa L.) (Chapter 1). The Dorycnium genus (canary clovers) contains perennial species that might be useful forage plants for southern Australia. Dorycnium are sub-shrubs and their plant form differs from current perennial forages (Chapter 1). The aim of this project was to investigate some of the agronomic traits of several species of the genus Dorycnium to explore where they might be used in Australia and how they might be integrated into agricultural systems for management of dryland salinity. First, two desktop investigations assessed the potential adaptation and role of Dorycnium species in southern Australia: a review of the current literature on the agronomic characteristics of Dorycnium (Chapter 2) and an eco-geographical analysis to explore the ecology of Dorycnium species (Chapter 3). The agronomy of Dorycnium has been previously researched mainly in New Zealand, and although this provides some indications on where and how Dorycnium might be best used in Australia, this still requires testing in Australia. In particular, the aluminium tolerance of Dorycnium species indicates that they may be more suitable for acid soils than lucerne. Little ecological data was obtained for germplasm and herbarium collection sites of Dorycnium species. Climate comparisons between the native distribution of Dorycnium species in the Mediterranean basin and Australia, using spatial aridity data and CLIMEX climate match modelling, revealed that D. hirsutum and D. rectum might be suitably adapted to the temperate pasture regions of southern Australia. Suitable germplasm of D. pentaphyllum may also exist, but subsequent investigations in this project focussed on D. hirsutum and D. rectum.

Style APA, Harvard, Vancouver, ISO itp.

17

Stringer, Christina Elaine. "Hydrologic Controls on Salinity in Mangroves and Lagoons". Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3583.

Pełny tekst źródła

Streszczenie:

This dissertation explores the hydrologic controls on salinity within mangroves and lagoons at sites in Florida and Mexico. The main objective of this research is to better understand hydrologic controls on mangrove ecosystem structure and develop ideas that will be useful to land managers attempting to regulate and conserve these critical habitats. This study was conducted at sites in Ft. Pierce, FL and Costalegre on the central Pacific coast of Mexico. We examined controls on water levels and salinity in a mangrove on a carbonate barrier island along the Indian River Lagoon, east-central Florida. Spectral analysis of water levels showed that mangrove groundwater levels are not tidally influenced. Salinities vary spatially, with values of ~10 in upland environments to ~75 psu in irregularly-flushed mangroves. Water chemistry indicates that water salinities are largely controlled by enrichment due to evapotranspiration. An electrical resistivity survey showed that the freshwater lens is restricted to uplands and that hypersaline waters extend deeply below the mangrove. These results indicate that evapotranspiration lowers water levels in the mangrove, which causes Indian River Lagoon water to flow into the mangrove where it evapoconcentrates and descends, forming a thick layer of high-salinity water below the mangrove. Spatial variability of terrain conductivity in the Ft. Pierce mangrove varied under two hydrologic management regimes, breached rotational impoundment management and rotational impoundment management. The difference in coefficient of variation (CV) between the breached RIM and RIM data was calculated to examine spatial variability in both the shallow and deep layers. A null-hypothesis model was employed to examine the statistical significance of the CV results. The average water levels were -0.06 m amsl and 0.49 m amsl during the breached-RIM and RIM regimes, respectively. The average shallow (EM31) layer terrain conductivity shifted slightly from 1868 mS m -1 to 1825 mS m-1 after the alteration in management regime, yet the standard deviation of these averages decrease from 656 mS m-1 to 216 mS m-1. The average deep (EM34) layer terrain conductivities were 328 mS m-1 and 255 mS m-1 during the breached-RIM and RIM regimes, respectively. The temporal CVs were 0.23 and -0.04 for the shallow and deep layers, respectively. The null-hypothesis model for the shallow layer illustrates that the difference in spatial structure is statistically significant. The deep layer CV was not statistically significant. These results indicate that the transition from breached RIM to RIM resulted in changes to both the physical and chemical hydrologic character of the impoundment, especially in the shallow layer. The second study sites were three mangrove communities along the central Pacific Mexican coast. Salinities varied by water type, with values of ~9 in La Manzanilla, ~17 in La Vena, ~33 in Barra de Navidad, ~0.4 in the fresh waters, and ~34 in the seawater. Sodium and Chloride concentrations and isotopic signatures, as well as salinity, were used as tracers in mass-balance mixing models to quantify estimates of relative fresh-water and seawater contributions to each site. La Manzanilla, a basin mangrove, had mean fresh-water contribution estimates of 63-84%. La Vena, a riverine mangrove, had fresh-water estimates of 39-51%. Barra de Navidad, a fringe mangrove, had low fresh-water contributions of 0-5%. These results illustrates that the role groundwater plays in mangrove hydrodynamics is dependent on the site hydrogeomorphology.

Style APA, Harvard, Vancouver, ISO itp.

18

Ghazzi, Pierre Albert. "Controls on and reduction of the sodicity hazard of soils of the Euphrates valley (Syria)". Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386392.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

19

Silva, Alexsandro Oliveira da [UNESP]. "Fertirrigação e controle da salinidade no cultivo de beterraba em ambiente protegido". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/93813.

Pełny tekst źródła

Streszczenie:

Made available in DSpace on 2014-06-11T19:26:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-07-30Bitstream added on 2014-06-13T20:15:40Z : No. of bitstreams: 1 silva_ao_me_botfca.pdf: 2497584 bytes, checksum: acd2b658d1dbff5be344d07027c33e34 (MD5)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Universidade Estadual Paulista (UNESP)
O uso em execesso de fertilizantes em cultivo sobre ambiente protegido pode levar à salinização, e esse processo pode ser monitorado pela condutividade elétrica na solução do solo. O presente trabalho foi realizado com o objetivo de avaliar a utilização de extratores em cápsulas porosas no manejo da fertirrigação e no controle do processo de salinização em cultivo de beterraba (Beta vulgaris L.). Duas cultivares de beterraba (Early Wonder Tall Top e Itapuã) foram avaliadas em função de dois manejos de fertirrigação, sendo o primeiro o manejo tradicional utilizado pelos produtores rurais e o segundo com uso de extratores de solução do solo para controle da salinidade. O experimento foi realizado em vasos de 14 L e salinizados artificialmente a diferentes níveis de condutividade elétrica no extrato de saturação (1,0; 3,0; 6,0; 9,0; 12,0; dSm-1). Os resultados obtidos demonstram que o controle através de extratores em cápsulas porosas é eficiente no monitoramento de solos com problemas de salinização. Observou-se também que o controle da solução do solo em níveis de condutividade elétrica desejados, proporcionou um efeito benéfico no cultivo da beterraba evitando desequilíbrios iônicos e salinização do solo. O cultivo em ambiente protegido proporcionou menor consumo hídrico e coeficiente de cultivo do que os citados na literatura para cultivo convencional. Os manejos da fertirrigação utilizados proporcionaram efeitos significativos nas variáveis relacionadas ao crescimento e produtividade da...
The excessive use of fertilizers in farming on protected environment can lead to salinization, and this process can be monitored by electrical conductivity in the soil solution. The present study was carried out to evaluate the extraction of soil solution by porous cups, which were used with the purpose to manage the fertigation and control the salinization in beet crop (Beta vulgaris L.) Two beet cultivars (Early Wonder Tall Top and Itapuã) were evaluated against two fertigation managements, the first being the traditional management used by farmers and the second with the use of soil solution extractors to control salinity. The experiment was carried out in 14 L pots and artificially salinized with different levels of electrical conductivity in the saturation extract (1.0, 3.0, 6.0, 9.0, 12.0, dS m-1). The results obtained show that control through porous cup extractors is effective in monitoring soil salinization problems. It was also observed that control of soil solution at desired levels of electrical conductivity, provided a beneficial effect in the beet cultivation avoiding ionic imbalance and salinization. The protected cultivation resulted in less water consumption and crop coefficient than those reported in the literature for conventional farming. The fertigation managements used offered significant effects on variables related to the growth and yield of beet, possibly due to increased fertilizer which increased soil salinity and caused nutrient imbalances in plants. The relative yield of the trees showed a drop from the salinity threshold... (Complete abstract click electronic access below)

Style APA, Harvard, Vancouver, ISO itp.

20

Silva, Alexsandro Oliveira da 1985. "Fertirrigação e controle da salinidade no cultivo de beterraba em ambiente protegido /". Botucatu : [s.n.], 2012. http://hdl.handle.net/11449/93813.

Pełny tekst źródła

Streszczenie:

Orientador: Antônio Evaldo Klar
Coorientador: Ênio Farias de França e Silva
Banca: Hélio Grassi Filho
Banca: Tales Miler Soares
Resumo: O uso em execesso de fertilizantes em cultivo sobre ambiente protegido pode levar à salinização, e esse processo pode ser monitorado pela condutividade elétrica na solução do solo. O presente trabalho foi realizado com o objetivo de avaliar a utilização de extratores em cápsulas porosas no manejo da fertirrigação e no controle do processo de salinização em cultivo de beterraba (Beta vulgaris L.). Duas cultivares de beterraba (Early Wonder Tall Top e Itapuã) foram avaliadas em função de dois manejos de fertirrigação, sendo o primeiro o manejo tradicional utilizado pelos produtores rurais e o segundo com uso de extratores de solução do solo para controle da salinidade. O experimento foi realizado em vasos de 14 L e salinizados artificialmente a diferentes níveis de condutividade elétrica no extrato de saturação (1,0; 3,0; 6,0; 9,0; 12,0; dSm-1). Os resultados obtidos demonstram que o controle através de extratores em cápsulas porosas é eficiente no monitoramento de solos com problemas de salinização. Observou-se também que o controle da solução do solo em níveis de condutividade elétrica desejados, proporcionou um efeito benéfico no cultivo da beterraba evitando desequilíbrios iônicos e salinização do solo. O cultivo em ambiente protegido proporcionou menor consumo hídrico e coeficiente de cultivo do que os citados na literatura para cultivo convencional. Os manejos da fertirrigação utilizados proporcionaram efeitos significativos nas variáveis relacionadas ao crescimento e produtividade da ... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The excessive use of fertilizers in farming on protected environment can lead to salinization, and this process can be monitored by electrical conductivity in the soil solution. The present study was carried out to evaluate the extraction of soil solution by porous cups, which were used with the purpose to manage the fertigation and control the salinization in beet crop (Beta vulgaris L.) Two beet cultivars (Early Wonder Tall Top and Itapuã) were evaluated against two fertigation managements, the first being the traditional management used by farmers and the second with the use of soil solution extractors to control salinity. The experiment was carried out in 14 L pots and artificially salinized with different levels of electrical conductivity in the saturation extract (1.0, 3.0, 6.0, 9.0, 12.0, dS m-1). The results obtained show that control through porous cup extractors is effective in monitoring soil salinization problems. It was also observed that control of soil solution at desired levels of electrical conductivity, provided a beneficial effect in the beet cultivation avoiding ionic imbalance and salinization. The protected cultivation resulted in less water consumption and crop coefficient than those reported in the literature for conventional farming. The fertigation managements used offered significant effects on variables related to the growth and yield of beet, possibly due to increased fertilizer which increased soil salinity and caused nutrient imbalances in plants. The relative yield of the trees showed a drop from the salinity threshold... (Complete abstract click electronic access below)
Mestre

Style APA, Harvard, Vancouver, ISO itp.

21

Olivier, Miriam Frances. "Temperature and salinity controls on methanogenesis in an artificial freshwater lake (Cardiff Bay, Wales)". Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/88353/.

Pełny tekst źródła

Streszczenie:

Cardiff Bay is an artificial freshwater lake created by the impoundment of 100 ha of estuarine intertidal mudflats in the early 2000s. This dramatic environmental change is reflected in the sedimentary record as a sharp transition between lacustrine gyttja and estuarine clay sediments. This study utilises a combination of geochemical, molecular genetic and novel cultivation based approaches to explore how the methanogen community of Cardiff Bay sediments has responded to the transition from brackish to freshwater conditions caused by impoundment, and how they might respond to future climate change. Microbial methanogenesis is active in newly deposited Cardiff Bay lacustrine gyttja sediments. Porewater methane concentrations regularly exceed saturation limits, suggesting that ebullition may be a direct pathway for atmospheric methane emissions. Sediment slurry incubations suggest that methane production in Cardiff Bay sediments would be further enhanced by both increased substrate availability and climate relevant temperature increases. Hydrogenotrophic methanogenesis mediated by the genus Methanobacterium is the major pathway for methane production in Cardiff Bay, which is atypical for either estuarine or freshwater environments, and reflects the importance of recalcitrant terrestrial carbon inputs. In fact, cultivation based experiments provide tentative evidence that syntrophic acetate and methylamine utilizing consortia involving hydrogenotrophic methanogens were able to outcompete acetotrophic and methylotrophic methanogens under certain environmental conditions. The temperature and salinity ranges and characteristics, and substrate types, of Cardiff Bay methanogenic communities varied little between sediments deposited pre- and post-impoundment. Differences between the methanogen community composition of lacustrine gyttja and estuarine clay sediments were driven predominantly by a reduction in the quantity and availability of organic matter with increasing sediment depth. A phylogenetically and physiologically diverse range of methanogens were enriched from Cardiff Bay sediments, including thermophilic methanogens and selected marine methanogens. Methanogen strains isolated from Cardiff Bay were closely related to cultivated strains, yet displayed novel physiological characteristics. These included a strain of the thermophilic genus Methanothermobacter able to produce methane at 25 °C, and a strain of the marine genus Methanolobus which grew under freshwater conditions (0.01 M NaCl).

Style APA, Harvard, Vancouver, ISO itp.

22

Silva, Ênio Farias de França e. "Manejo da fertirrigação e controle da salinidade na cultura do pimentão utilizando extratores de solução do solo". Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-26072002-152339/.

Pełny tekst źródła

Streszczenie:

O presente trabalho foi realizado com o objetivo de avaliar a utilização de extratores providos de cápsulas cerâmicas no manejo da fertirrigação e no controle do processo de salinização em um cultivo de pimentão (Capsicum annuum L.), ocasionado pelo acúmulo de fertilizantes aplicados em excesso, a partir de um monitoramento da condutividade elétrica da solução do solo e de nutrientes específicos (potássio e nitrato) pelo uso de testes rápidos. Foram analisados os efeitos da técnica proposta no crescimento vegetativo e no rendimento obtido no cultivo de pimentão sob ambiente protegido. Utilizaram-se dois solos com texturas distintas, um franco arenoso e o outro franco argiloso, ambos contidos em vasos de 62 L e salinizados artificialmente a diferentes níveis de condutividade elétrica no extrato de saturação, variando de 1 até 9 dS m-1. Os resultados obtidos demonstraram que com a técnica proposta pode-se monitorar a concentração iônica da solução do solo além de possibilitar a determinação dos íons potássio e nitrato com alta precisão, cálcio e magnésio com precisão satisfatória e que não é recomendado a determinação da concentração de enxofre e fósforo na solução do solo. Observou-se também que o controle dessa solução em níveis desejados proporcionou um efeito benéfico no cultivo do pimentão além de evitar desequilíbrios iônicos e salinização dos solos. Os íons nitrato e potássio podem ser determinados e monitorados ao longo do ciclo da cultura pelo uso de testes rápidos. Os níveis crescentes de salinidade inicial do solo ocasionaram para o solo franco-arenoso uma redução no rendimento da cultura, bem como, nas variáveis vegetativas e consumo hídrico. Entretanto, para o solo franco-argiloso ocorreu uma tendência de incremento das variáveis de crescimento e produção com o aumento da salinidade inicial do solo, fato esse, atribuído à redução do efeito da salinidade inicial sobre as plantas de pimentão, ocasionada possivelmente pela distribuição de sais no solo. Os manejos da fertirrigação não proporcionaram efeitos discrepantes nas variáveis relacionadas ao crescimento e produção do pimentão, em virtude da recomendação e marcha de absorção de nutrientes escolhidos para o manejo tradicional adaptar-se bem a extração de nutrientes pela cultura.
The objective of this study was evaluating the use of extractors provided of ceramic cups on fertigation management and on the control of salinization in cultivation of bell pepper (Capsicum annuum L.), caused by excessive fertilization, by means of monitoring the electrical conductivity of soil solution and specific nutrients (potassium and nitrate) using quick tests. The effects of the proposed technique on vegetative development and yield of bell pepper in greenhouse were analyzed. Two soils with different textures were used, sandy-loam and clay-loam, both packed in pots of 62 L, which were artificially salinized in order to obtain electrical conductivities of the saturation extract varying from 1 to 9 dS m-1. Results showed that the proposed technique allows monitoring of ionic concentration of soil solution and permits the determination of the K and NO3 with high accuracy, Ca and Mg with satisfactory accuracy and are not recommended for determination of the S and P concentration in soil solution. Maintaining the nutrients concentration and electrical conductivity of the soil solution at desired levels provide many advantages for the cultivation of bell pepper in greenhouse besides avoiding ionic unbalances and soil salinization. NO3 and K concentrations may be determined and monitored along of crop season by quick test. The crescent levels of initial soil salinity decreased yield, vegetative variables and water uptake for the sandy loam soil. However, for the clay-loam soil an increasing tendency occurred for growing variables and yield with increasing initial soil salinity, probably because the low effect of initial soil salinity on crop development, which was caused by the salts distribution pattern in the soil. The different fertigation management did not produced disagreeing effects on variables related to crop growth and yield, because the chosen recommendation and uptake rate curve for the traditional fertigation management supplied the crop nutritional requirements.

Style APA, Harvard, Vancouver, ISO itp.

23

Laranjeira, Isabel Maria Fernandes. "Controlo do risco de salinização de um solo de barro (vertissolo) melhorando a drenagem interna com subsolagem e drenos toupeira". Master's thesis, Universidade de Évora, 2006. http://hdl.handle.net/10174/16441.

Pełny tekst źródła

Streszczenie:

O objetivo deste trabalho é o de estudar um conjunto de técnicas de drenagem em regadio (subsolado e drenos toupeira) que garantam a melhoria das condições de drenagem interna dos solos de Barro (Vertissolos), contribuindo enquanto condições base para a sua proteção contra a salinização. Os resultados discutidos no presente trabalho decorrem da monitorização da salinidade do solo, numa parcela localizada no Outeiro em Ferreira do Alentejo, onde foram instalados em solo de Barro (Cp): drenos de plástico com subsolagem e com drenos toupeira e drenos toupeira apenas. Estando sujeita em anos anteriores a culturas de sequeiro, a parcela foi regada com água de má qualidade (C3S1) da Ribeira de Canhestros. A variação vertical de sais deve-se a efeitos da pouca lixiviação verificada durante a campanha de rega, na sequência das pequenas dotações de rega aplicadas e da quase nula precipitação verificada neste período. /ABSTRACT - The objective is to study a set of techniques in irrigated agriculture that contribute to improve drainage of the Vertisol soils, protecting them against salinity. Discussed results were obtained by monitoring an experiment field with Barros clay soils in Outeiro (Ferreira do Alentejo). A basic drainage system was built based on perforated plastic pipe drains, complemented with three experiment modalities: no further soil deep loosening; subsoiling; mole drains. A supplementary modality was later established consisting on mole drains opening directly into a drainage channel, without basic drainage network. The experiment field was irrigated With poor quality water fi'om the neighbor Canhestros River (C3Sl) and salt contents evolution was monitored within the soil profile and in the drainage water, as compared to soil salinity initial status, which resulted from several years of cereal rainfed cropping. Important salt increase was observed which is due to poor drainage and rain scarcity during the experiment.

Style APA, Harvard, Vancouver, ISO itp.

24

Blanco, Flávio Favaro. "Tolerância do pepino enxertado à salinidade em ambiente protegido e controle da salinização do solo". Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-10022003-141143/.

Pełny tekst źródła

Streszczenie:

A aplicação de fertilizantes via água de irrigação é prática comum para cultivos em ambiente protegido, o que pode resultar na salinização do solo se o manejo da irrigação não for adequado. Com isso, é de grande importância que se estabeleça a tolerância das culturas à salinidade e o controle eficiente da irrigação para cada cultura a fim de se promover a lixiviação do excesso de sais da zona radicular até um nível tolerado pelas plantas. O presente trabalho teve o objetivo de estabelecer um manejo adequado da fertilização e da irrigação para a cultura do pepino enxertado em ambiente protegido, visando o controle da salinidade do solo, e avaliar métodos de recuperação do solo salinizado. Para isso, foi conduzido um experimento em uma estufa de 110 m 2 para estudar o efeito de diferentes salinidades da água de irrigação (S1=1,58 dS.m -1, S2=3,08 dS.m -1 e S3=5,13 dS.m -1 ), diferentes lâminas de água (L0=1,00.ETc e L1=1,25.ETc) e duas frequências de aplicação da lâmina L1 (F1=em todas as irrigações e F2=quando a lâmina de irrigação acumulada em L0 for igual a 100 mm) no desenvolvimento vegetativo e produção do pepino, cv. Hokushin, enxertado em Cucurbita spp., híbrido Excite-Ikki. O manejo da irrigação foi realizado através de tensiômetros instalados a 15 e 30 cm de profundidade e da evaporação de um tanque reduzido, instalado no interior da estufa. Os resultados obtidos demonstraram que o aumento de uma unidade de salinidade da água de irrigação reduziu a produção total e comercial em 2,83 e 2,99%, respectivamente, não apresentando diferenças significativas. O número de frutos comerciais por planta foi reduzido em 3,32% para cada incremento de uma unidade de salinidade. A salinidade também afetou significativamente a área foliar unitária e o índice de área foliar, bem como a altura e o diâmetro do colo da planta. As diferentes lâminas de irrigação e frequências de aplicação de L1 não resultaram em diferenças significativas para a produção e componentes de produção da cultura. O aumento de uma unidade de salinidade do solo reduziu a produção e o número de frutos por planta, comercial e total, em 7,24 e 6,71% e 8,04 e 7,58%, respectivamente, os quais foram bem inferiores aos valores citados na literatura. A pequena redução na produção e a ausência de diferenças significativas entre os níveis de salinidade não permitiram definir a tolerância do pepino à salinidade e o manejo da lâmina de irrigação quando a água utilizada apresenta alto teor salino. A salinidade do solo aumentou proporcionalmente com o aumento da salinidade da água, sendo que as lâminas de irrigação e as frequências de aplicação de L1 não foram suficientes para reduzir a salinidade do solo, embora a frequência F2 tenha resultado em um aumento mais lento da salinidade. A lixiviação do excesso de sais do solo após o cultivo demonstrou que a aplicação da lâmina de lavagem por gotejamento foi mais eficiente do que a inundação na redução da salinidade do solo. Concluiu-se que a lâmina relativa de lavagem e o valor do coeficiente k a serem utilizados são, respectivamente, de 0,9 e 0,1 para gotejamento e 1,3 e 0,2 para inundação, com base na lâmina calculada pela equação de Rhoades & Loveday (1990).
Fertilizers application through irrigation water is a very common practice for greenhouse cultivation conditions, which can result in the soil salinization if irrigation management is not appropriated. It is very important to establish the crop tolerance to salinity and the efficient irrigation control for each crop to promote leaching of excess salts from the root zone until a tolerated level by plants. The present work had the aim to establish an adapted management of fertilization and irrigation for grafted cucumber cultivated in greenhouse, in order to control the soil salinity, and to evaluate methods of salinized soil reclamation. An experiment has been carried out in a 110 m 2 greenhouse to study the effects of different irrigation water salinity (S1=1,58 dS.m -1 , S2=3,08 dS.m -1 and S3=5,13 dS.m -1 ), different irrigation water depth (L0=1,00.ETc and L1=1,25.ETc) and two applications frequencies of L1 (F1=at every irrigations and F2=when accumulated irrigation water depth in L0 reaches 100 mm) on vegetative development and yield of cucumber, cv. Hokushin, grafted onto Cucurbita spp., hybrid Excite-Ikki. Irrigation management was made by tensiometers installed at 15 and 30 cm deep and by a reduced pan evaporation, installed inside the greenhouse. The results showed that the increment of one unit of irrigation water salinity reduced the total and marketable yield at 2,83 and 2,99%, respectively, not showing significantly reduction. Marketable fruits number per plant was reduced at 3,32% for each increment of one unit of salinity. Salinity also affected significantly the unitary leaf area and the leaf area index, as the height and stem diameter of the plants. The different irrigation water depths and frequencies of L1 application did not result in differences for yield and yield components. Each increment of one unit of salinity reduced yield and fruit number per plant, marketable and total, of 7,24 and 6,71% and 8,04 and 7,58%, respectively, which were smaller than that found on literature. Little reduction in yield and the lack of significantly differences between the levels of salinity did not allow to define cucumber tolerance to salinity and the irrigation management for high salinity irrigation water. Soil salinity increased proportionally to irrigation water salinity increasing, but irrigation water depths and application frequencies of L1 were not sufficient to reduce soil salinity, though the frequency F2 resulted in a slower increasing of soil salinity. Leaching of excess salts after cultivation showed that the application of leaching water depth by drip irrigation was more effective than the application by flooding on soil salinity reduction. We concluded that the relative leaching depth and the k coefficient value to be adopted are, respectively, 0,9 and 0,1 for drip irrigation and 1,3 and 0,2 for flooding, based on water depth calculated by equation of Rhoades & Loveday (1990).

Style APA, Harvard, Vancouver, ISO itp.

25

Medeiros, Pedro Róbinson Fernandes de. "Manejo da fertirrigação em ambiente protegido visando o controle da salinidade para a cultura do tomate em solo franco-argiloso". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-11022011-100428/.

Pełny tekst źródła

Streszczenie:

Em condições de ambiente protegido, o controle da salinidade e o manejo da fertirrigação se confundem, pois os sais fertilizantes utilizados na maioria das vezes são as principais causas de salinização. Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos essenciais a nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. O objetivo desta pesquisa foi calibrar e avaliar o uso de extratores de cápsula porosa, para o monitoramento da solução do solo, visando auxiliar no manejo da fertirrigação e no controle da salinização, como também, estudar o efeito de diferentes níveis de salinidade, obtidos com base em curvas artificiais de salinização do solo, sobre a cultura do tomate utilizando a cultivar Débora Plus. As plantas foram submetidas aos seguintes tratamentos: seis níveis iniciais de salinidade do solo induzida por sais fertilizantes (S1 = 1,0; S2 = 2,0; S3 = 3,0; S4 = 4,0; S5 = 5,0 e S6 = 6,0 dS m-1) e dois tipos de manejo de fertirrigação, o tradicional (M1) e um manejo de fertirrigação com controle do nível de salinidade do solo durante todo o ciclo da cultura (M2); visando observar se o manejo M2 é capaz de manter a salinidade do solo a níveis desejados. O delineamento estatístico adotado foi o de blocos casualizados completos com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2, totalizando 48 parcelas por estufa. Este estudo foi conduzido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Observou-se que os extratores de cápsula porosa possibilitaram monitorar a concentração de íons na solução do solo, bem como direcionar o manejo de fertirrigação M2, com a manutenção da salinidade em níveis desejados, a partir do controle da condutividade elétrica da solução do solo. Os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção e o desenvolvimento vegetativo das plantas, o pH e o oBrix dos frutos e o pH e a concentração de nitrato (NO3 -) da solução do solo. Pode-se verificar que a manutenção da condutividade elétrica da solução do solo pelo manejo M2 em um determinado nível ótimo de salinidade, realmente promove incremento da produção quando contrastada com o manejo tradicional de fertirrigação M1, em ambiente protegido com solo franco-argiloso.
In protected environment conditions, the control of salinity and the fertirrigation management mingle themselves, because most of times the fertilizer salts are the main responsible for the salinization. With the periodical monitoring of the soil solution, the electrical conductivity and the concentration of specific ions can be determined. Among the techniques of extraction of the soil solution the porous cup extractor stands for its practicality in the field, low cost, easy-handling, and good precision. The aim of the research was to calibrate and evaluate the use of porous cup extractors, for the soil solution monitoring in order to aid the management of fertirrigation and the control of the salinization, as well as, study the effect of different levels of salinity, obtained based on artificial curves of soil salinization, on the tomato crop using Débora Plus. The plants were subjected to the following treatments: six initial levels of soil salinity induced by fertilizer salts (S1 = 1,0; S2 = 2,0; S3 = 3,0; S4 = 4,0; S5 = 5,0 E S6 = 6,0 dS m-1). and two types of fertirrigation management, the traditional (M1) and a fertirrigation management with the control of the level of soil salinity throughout the crop cycle (M2); in order to observe if the management M2 is able to maintain the salinity of the soil to desired levels. The Statistic design adopted was the randomized complete block with four repetitions, leaving the studied factors arranged in the factorial scheme 6 x 2, total 48 plots for each protected environment. This study was carried area in the experimental at the Biosistems Engineering Department at ESALQ/USP, Piracicaba, SP. It has been observed that porous cup extractor could monitor the concentration of ions in the soil solution, as well as how to direct the fertirrigation management M2, with the maintenance of the salinity in desired levels. The levels of soil salinity from the accumulation of fertilizer salts affected directly the variables: water consumption, production and the vegetative development of the plants, the pH and the oBrix of the fruit and the pH and the nitrate concentration (NO3 -) of the soil solution. It can be seen that the electrical conductivity maintenance in an excellent level of salinity really promotes the increase of productivity when it contrasts with the traditional fertirrigation management M1, in a protected environment with sandy-clayey soil.

Style APA, Harvard, Vancouver, ISO itp.

26

Dias, Nildo da Silva. "Manejo da fertirrigação e controle da salinidade em solo cultivado com melão rendilhado sob ambiente protegido". Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-13092004-171203/.

Pełny tekst źródła

Streszczenie:

Com o objetivo de avaliar o uso de extratores de soluções do solo no auxílio ao manejo da fertirrigação e no controle da salinidade em solo cultivado com melão rendilhado, conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia Rural da ESALQ/USP, localizado no município de Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,0; S2 = 2,0; S3 = 3,0; S4 = 4,0; S5 = 5,0 e S6 = 6,0 dS m-1) e dois manejos de fertirrigação: tradicional e com controle da condutividade elétrica da solução do solo. O delineamento estatístico adotado foi o de blocos casualizados completos com 4 repetições, sendo os fatores estudados arranjados em um esquema fatorial de 6 x 2. A salinização inicial do solo se procedeu por meio da aplicação de soluções salinas preparadas a partir de fertilizantes, sendo que a quantidade de sais a ser adicionada foi determinada tomando por base uma curva de salinização artificial obtida previamente em laboratório. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelam que as produções total e comercial, além do peso médio total dos frutos foram significativamente reduzidos com o incremento dos níveis de salinidade do solo Os efeitos da salinidade do solo sobre a altura e o diâmetro das plantas foram mais severos durante o desenvolvimento vegetativo inicial do que no início da frutificação, o que sugere uma possível adaptação das plantas ao estresse salino ao longo do tempo. Embora não tenha sido possível se detectar diferenças expressivas causadas pelos dois tipos de manejo da fertirrigação no desenvolvimento ou na produção da cultura, o uso dos extratores de solução permitiu auxiliar no manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo.
A study was carried out under greenhouse conditions, at the experimental area of the Department of Rural Engineering of Escola Superior de Agricultura Luiz de Queiroz-USP, Piracicaba, São Paulo State, Brazil, with the aim of evaluating ceramic cup samplers used to facilitate fertirrigation management and soil salinity control on a netmelon crop, was carried out The treatments comsisted of two combination factors: six level of initial soil salinity (S1 = 1.0, S2 = 2.0, S3 = 3.0, S4 = 4.0, S5 = 5.0 and S6 = 6.0 dS m-1) and two fertirrigation managements: the traditional and the control of eletrical conductivity of soil solucion. The statiscal test was in randomized blocks, with four replications, arranged in 6 x 2 factorial design. The initial soil salinity value was obtained by appling saline solutions of fertilizer salts using an artificial soil salinization curve obtained previously in laboratory. The electrical conductivity in soil solucion was measured after each irrigation using ceramic cup samplers. Results showed that both total and marketable fruit yield and total weight per fruit were significantly reduced by increase in soil salinity level. The soil salinity effects on plants height and stem diameter were more severe during early vegetative growth than in the beginning of fruit set. This suggests a possible plant adaptation to saline stress along the time. Although no differences were observed in case fertirrigation management treatments on plants development or yield, however the use of solution extractors helped in fertirrigation management because them permitted to keep soil solution salinity at desired level.

Style APA, Harvard, Vancouver, ISO itp.

27

Tavares, Antonio Clarette Santiago. "Manejo da fertirrigação e controle da salinidade para a cultura do pimentão (Capsicum annuum) utilizando medidores de íons da solução do substrato". Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-06032006-140814/.

Pełny tekst źródła

Streszczenie:

A produção agrícola, de maneira geral, sofre ação direta das condições climáticas e da exigência em insumos. Dentre as olerícolas cultivadas sob estufas no Estado de São Paulo, o pimentão destaca-se pelo volume total comercializado. No entanto, o manejo inadequado da irrigação, a adição de fertilizantes em altas dosagens e a inexistência de chuvas promotoras de lixiviação destes sais podem causar salinização e desequilíbrio nutricional dos solos ou dos substratos de cultivo nas áreas sob estufas. O objetivo desse trabalho foi estabelecer uma comparação entre a fertirrigação que é feita de forma convencional e o manejo da fertirrigação via monitoramento da concentração dos íons na solução iônica do meio de cultivo, assim como a definição de níveis adequados de N e K2O na prática da fertirrigação para essa cultura. O experimento foi conduzido no Departamento de Engenharia Rural da Escola Superior de Agricultura Luiz de Queiroz USP, no município de Piracicaba-SP, em vasos com substrato de fibra de coco, em uma estufa plástica com cobertura em arco. Os tratamentos foram compostos da combinação de 4 doses de N aplicadas via fertirrigação (N1= 200, N2= 300, N3= 400 kg ha-1 de N, N4= manutenção da concentração de NO3 - na solução do substrato entre 7 a 15 mmolc L-1) e 4 doses de K aplicadas via fertirrigação (K1= 450, K2= 550, K3= 650 kg ha-1 de K2O, K4= manutenção da concentração de K+ na solução do substrato entre 3 a 4 mmolc L-1). O delineamento estatístico adotado foi o de blocos casualizados com 4 repetições, arranjado no esquema fatorial 4x4. Os tratamentos não tiveram influência no crescimento da planta e nem no diâmetro do colo. O peso médio dos frutos diminuiu linearmente com o aumento da dose aplicada de nitrogênio e potássio. Conseguiu-se as melhores produções e com os mesmos padrões comerciais, com doses menores de nitrogênio e potássio O uso de extratores de soluções associado aos medidores de íons NO3 - e K+, mostrou-se eficiente no manejo das fertirrigações para a cultura do pimentão. A produtividade referente a dose de nitrogênio e potássio obtida pelo manejo proposto esteve entre as maiores produtividades conseguidas.
The agricultural production, in a general way, suffers direct action of the climatic conditions and of the demand in inputs. Among the cultures cultivated under greenhouses in the State of São Paulo, the bell pepper stands out with a great total marketed volume. However, the inadequate irrigation management the addition of fertilizers in high dosages and the inexistence of rains promoters' of leaching of these salts can cause salinization and nutritional unbalance of the soils or cultivation substrata in areas under greenhouses. The objective of this work was to establish a comparison among the fertigation done by the conventional form and the fertigation management through monitoring the ions concentration in the ionic solution of the cultivation, as well as the definition of appropriate levels of N and K2O in practice of the fertigation for that culture. The experiment was conducted at the Department of Rural Engineering of the Escola Superior de Agricultura "Luiz de Queiroz" USP, at municipal district of Piracicaba-SP, in vases with substratum of coconut fiber, in a plastic greenhouse with covering in arch. The treatments were composed by combination of 4 doses of N (N1 = 200, N2 = 300, N3 = 400 kg ha-1 of N, N4 = concentration maintenance of NO3 - in the solution of the substratum among 7 to 15 mmolc L-1) and 4 doses of K (K1 = 450, K2 = 550, K3 = 650 kg ha-1 of K2O, K4 = maintenance of the concentration of K+ in the solution of the substratum among 3 to 4 mmolc L-1). The adopted statistical design was randomized blocks with 4 repetitions, arranged in the factorial outline 4x4. Treatments didn't have influence an the plant growth and in the lap diameter neither. The medium weight of the fruits decreased linearly with the increase of the applied dose of nitrogen and potassium. It was found better productions and with the same commercial patterns, with smaller doses of nitrogen and potassium. The use of solutions extractors associated to the ions meters NO3 - and K+, was shown efficient in the fertigation management for the crop of the bell pepper. The yield regarding doses of nitrogen and potassium obtained by the proposed management were among the largest productivity obtained.

Style APA, Harvard, Vancouver, ISO itp.

28

Silva, Everaldo Moreira da. "Manejo da fertirrigação em ambiente protegido visando o controle da salinidade do solo para a cultura da berinjela". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11143/tde-09022011-110850/.

Pełny tekst źródła

Streszczenie:

Com o monitoramento periódico da solução do solo, pode-se determinar a condutividade elétrica e a concentração de íons específicos, essenciais à nutrição das plantas. Dentre as técnicas de extração da solução do solo, o extrator de cápsula porosa destaca-se pela praticidade em campo, baixo custo, fácil manejo e boa precisão. Com isso objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido, e averiguar se a manutenção da condutividade elétrica em um determinado nível promove incremento da produção, quando contrastada com o manejo tradicional da fertirrigação. Conduziu-se um estudo em ambiente protegido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1) e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1), e o tradicional (M2), obedecendo a curva de absorção de nutrientes da cultura anteriormente estabelecida. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, ficando os fatores estudados arranjados no esquema fatorial 6 x 2. Os diferentes níveis de salinidade inicial do solo foram obtidos com solos de cultivos anteriores, no qual tinha-se como fonte de variação o nível de condutividade elétrica (CE), ocasionada pela adição de fertilizantes em ambiente protegido. A condutividade elétrica da solução foi medida após o término de cada evento de irrigação, utilizando-se extratores com cápsulas porosas. Os resultados revelaram que os níveis de salinidade do solo provenientes do acúmulo de sais fertilizantes afetou diretamente as variáveis consumo hídrico, produção de frutos, produção de matéria seca, índice de área foliar e o desenvolvimento vegetativo das plantas. O uso dos extratores de solução permitiu auxiliar o manejo da fertirrigação, mantendo os níveis desejados de salinidade da solução do solo ao longo do tempo. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1.
Periodic monitoring of soil solution allow to determine the electrical conductivity and concentration of specific ions essential to plant nutrition. Among the extraction techniques of soil solution, the porous cup extractors distinguished by their practicality in the field, low cost and good accuracy. This study has to aim to evaluate the effects of different levels of soil salinity on phenological and production of eggplant grown in pots in a greenhouse, and compare whether the control of the electrical conductivity in a certain level promotes increase the yield when compare to the traditional fertigation management . A study was conducted in a greenhouse in the Department of Biosystems Engineering, ESALQ / USP, Piracicaba, SP, Brazil. The treatments consisted of a combination of two factors: six levels of initial soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1) and two fertigation management: electrical conductivity control of soil solution (M1) and traditional (M2) by following the absorption curve of nutrients from the crop previously established. The statistical design was a randomized complete block with four repetitions, the factors studied arranged in 6 x 2 factorial. The different levels of initial soil salinity were obtained with soils where previous crop had been cropped in a source of variation in the level of electrical conductivity (EC), caused by the addition of fertilizer in a pots. The solution electrical conductivity was measured after each irrigation event, using extractants with ceramic cups. The results showed that levels of soil salinity caused by the accumulation of fertilizer salts affected directly the variables: water use, fruit yield, dry matter production, leaf area index and plant growth. The use of extractors solution allowed to control the fertigation management, and maintain the desired levels of salinity in the soil solution during the evaluated period. It appears that the reduction in eggplant yield in greenhouse was approximately 8.65% for step of 1 dS m-1 in soil salinity, the threshold salinity was 1.71 dS m-1.

Style APA, Harvard, Vancouver, ISO itp.

29

Lettéron, Alexandre. "Caractérisation sédimentologique, stratigraphique et paléoenvironnementale du système carbonaté lacustre à salinité variable du bassin d'Alès et des régions limitrophes (Priabonien, SE France) : implications paléoclimatiques et paléogéographiques". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0084.

Pełny tekst źródła

Streszczenie:

Les systèmes carbonatés lacustres salins présentent un fort potentiel d’enregistrement des changements paléogéographiques et paléoclimatiques. Ce manuscrit présente une méthode d’analyse pluridisciplinaire (sédimentologie, écologie, stratigraphie, paléontologie, géochimie et paléomagnétisme) et multi-échelle (µm au km) appliquée au bassin lacustre d’Alès et des régions limitrophes au cours du Priabonien (–38 à –33,5Ma). Cette approche a permis d’apporter de nouveaux éléments dans les reconstitutions paléoenvironnementales, paléogéographiques et paléoclimatiques du sud–est de la France au Priabonien. De nouveaux concepts sédimentologiques et stratigraphiques transposables à d’autres systèmes lacustres sont mis en avant. Enfin, les observations permettent de reconstituer, dans un cadre temporel bien contraint, l’histoire de la détérioration climatique précédant la limite Eocène–Oligocène qui correspond à la plus grande crise climatique de ces 50 derniers millions d’années
Lacustrine carbonate systems are of great interest to record the paleogeographic and paleoclimatic changes. This manuscript provides a multi-disciplinary (sedimentology, ecology, stratigraphy, paleontology, geochemistry and paleomagnetism) and a multi-scale (from µm to km) analysis dedicated to the Alès Basin and the neighboring areas during the Priabonian (–38 to –33.5Ma). Such joint approach has already allowed us to bring new elements regarding the paleoecological, paleoenvironmental and paleoclimatic interpretations. New sedimentological ideas and stratigraphic concepts emerge and could be transposed to such saline lacustrine systems as analogues. Finally, the well-defined chronostratigraphic framework can be used to decipher the climatic deterioration recording prior to the Terminal Eocene Event at the Eocene–Oligocene boundary (the most profound climatic change of the past 50 million years

Style APA, Harvard, Vancouver, ISO itp.

30

Greiner, Eric. "Mise en oeuvre de méthodes de contrôle optimal pour l'assimilation de données in situ et satellitaires dans les modèles océaniques". Paris 6, 1993. http://www.theses.fr/1993PA066108.

Pełny tekst źródła

Streszczenie:

L'etude porte sur la resolution de problemes de moindres carres non lineaires rencontres dans le domaine des ecoulements oceaniques a grande echelle. L'originalite de ce travail reside dans l'approche qui est faite par la methode du controle optimal plutot que par une technique statistique. Cette methode consiste a minimiser une fonctionnelle correspondant au probleme de moindre carre etudie, le minimum de cette optimisation etant une solution du probleme. Lors des applications numeriques, le gradient de cette fonctionnelle n'est pas calcule par differences finies mais a l'aide du modele adjoint. La premiere etude de cette these concerne l'estimation des conditions initiales manquantes de modeles oceaniques tels que ceux de saint-venant, stokes et boussinesq a l'aide de donnees partielles sur l'etat du systeme. Cette etude theorique faite essentiellement en lineaire est suivie d'une application reelle, l'initialisation d'un modele shallow water non lineaire avec des donnees d'altimetrie du satellite geosat. La troisieme etude traite de l'initialisation d'un modele non lineaire de boussinesq quasi stationnaire avec des donnees de temperature et de salinite uniquement. Cette etude theorique est suivie d'une experience numerique d'initialisation d'un modele operationnel de simulation oceanique tridimensionnelle a l'aide de donnees in situ de temperature et de climatologie de temperature et de salinite. Les resultats theoriques partiels ainsi que les experiences numeriques montrent que la methode s'applique de maniere satisfaisante et qu'elle pourra etre utilisee de maniere operationnelle ainsi qu'en mode recherche pour ameliorer notre vision de l'ocean et parfaire sa description

Style APA, Harvard, Vancouver, ISO itp.

31

Kuper, Marcel. "Irrigation management strategies for improved salinity and sodicity control". Phd thesis, 1997. http://tel.archives-ouvertes.fr/tel-00422363.

Pełny tekst źródła

Streszczenie:

An integrated approach is developed to assess a priori the effects of irrigation management interventions on soil salinity, sodicity and transpiration. The approach is tested for a 75,000 ha irrigation system in Pakistan, where canal and groundwater are used conjunctively. The main hypothesis is that by reallocating good quality canal water, the use of poor quality groundwater can be restricted, thus combating salinity and sodicity and mitigating their effects on crops. The study has three components. Firstly, interventions in canal water deliveries to tertiary units are analyzed using an unsteady state hydraulic model, based on the St. Venant equations, and linked with a regulation module, which captures the operational decisions of the irrigation agency. By changing the operational rules at the main canal, and by redimensioning the outlets in secondary canals, the water can be distributed equitably to tertiary units or delivered to those units that require it for salinity control. Secondly, the impact of irrigation on salinity, sodicity and transpiration is assessed for farmers' fields, using a combined soil water flow and solute transport model, based on Richard's equation and the convection-dispersion equation, and a regression equation, based on the irrigation quality and soil texture. A curvilinear relationship with a decreasing tangent was found between the irrigation quantity and soil salinity. Increases in the EC of the irrigation water result in a parallel curve with higher salinity levels. Adapting the irrigation quantity and quality to the existing soil types and depth to groundwater table can, therefore, reduce salinity and sodicity, thus avoiding soil degradation, which already occurs at an ESP of 4%. Thirdly, both components are combined with a parallel, socio-economic study, where farmers' decisions related to the crop portfolio and acquisition/application of water, were captured in Linear Programming models. The individual models of both studies are interfaced to develop a tool, capable of quantifying the effect of irrigation management interventions. For a secondary canal serving 14,000 ha, it is shown that the area threatened by sodicity is reduced by 40% by reallocating canal water, without affecting the agricultural production. The results of the developed tool should not be taken as accurate predictions, as there are likely to be unforeseen events due to the complexity of irrigation systems. Instead, the approach should be evaluated for its effectiveness in supporting actors' decisions in irrigation system management, by enhancing their understanding of the effects of interventions on salinity, sodicity and agricultural production. The application of the approach, in two case studies, shows that it allows the investigation of a wide range of policy and management interventions, and captures adequately the complexity of an irrigation system, thus providing indications about its transferability. However, the tools should be applied as part of an integrated concept, which includes phases of diagnosis, identification of relevant processes and parameters, and discussions with actors.

Style APA, Harvard, Vancouver, ISO itp.

32

Taylor, Peter John 1957. "Potential impacts of interception belts on the management of dryland salinity". 1999. http://web4.library.adelaide.edu.au/theses/09AGRP/09agrpt245.pdf.

Pełny tekst źródła

Streszczenie:

Bibliography: p. 161-185. The main aim of this project was to establish whether or not interception belts can be expected to transpire sufficient volumes of water to be considered a feasible option for controlling rising groundwater. (conclusion)

Style APA, Harvard, Vancouver, ISO itp.

33

"Osmoregulatory control of the gene expression of growth hormone receptor and prolactin receptor in black seabream (Acanthopagrus schlegeli)". 2005. http://library.cuhk.edu.hk/record=b5892531.

Pełny tekst źródła

Streszczenie:

Fung Chun Kit.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.
Includes bibliographical references (leaves 117-139).
Abstracts in English and Chinese.
Declaration of Originality --- p.i
Acknowledgements --- p.ii
Abstract --- p.iii
摘要 --- p.v
List of figures --- p.vi
List of tables --- p.viii
List of abbreviations --- p.ix
Chapter Chapter I --- General introduction --- p.1
Chapter 1.1 --- Different fish habitats with various salinities --- p.1
Chapter 1.2 --- Osmotic challenges faced by teleosts --- p.2
Chapter 1.3 --- High ionic strength results in DNA damage and excess water gain --- p.3
Chapter 1.4 --- Osmoregulatory organs and mechanisms for osmotic balance --- p.4
Chapter 1.5 --- Different tolerance to salinity changes --- p.8
Chapter 1.6 --- Effective communication among osmoregulatory organs --- p.9
Chapter 1.7 --- Introduction to GH and PRL --- p.9
Chapter 1.8 --- Structure of the GHR and PRLR --- p.10
Chapter 1.9 --- Hypoosmoregulatory action of GH/IGF-I axis in teleosts --- p.11
Chapter 1.10 --- Hyperosmoregulatory action of PRL in teleosts --- p.11
Chapter Chapter II --- Research rationale --- p.13
Chapter 2.1 --- Physiological importance of osmoregulation in fish --- p.13
Chapter 2.1.1 --- Energy metabolism --- p.13
Chapter 2.1.2 --- Growth --- p.14
Chapter 2.1.3 --- Immunity --- p.14
Chapter 2.1.4 --- Reproduction --- p.15
Chapter 2.2 --- Aquaculture importance --- p.15
Chapter 2.3 --- Unknown molecular regulatory mechanism of hormones during salinity changes in fish --- p.16
Chapter 2.4 --- Animal model --- p.17
Chapter Chapter III --- In vivo studies of sbGHR and sbPRLR expression in osmoregulatory organs in response to salinity changes --- p.18
Chapter 3.1 --- Introduction --- p.18
Chapter 3.1.1 --- Dynamic change of GH level during salinity changes --- p.18
Chapter 3.1.2 --- Dynamic change of PRL level during salinity changes --- p.19
Chapter 3.1.3 --- In vitro studies of GH and PRL release from teleost pituitary in response to extracellular osmolality changes --- p.20
Chapter 3.1.4 --- Biological actions of GH and PRL through the GHR and PRLR --- p.21
Chapter 3.2 --- Materials and methods --- p.23
Chapter 3.3 --- Results --- p.28
Chapter 3.4 --- Discussion --- p.36
Chapter 3.4.1 --- Plasma osmolality change during salinity changes --- p.36
Chapter 3.4.2 --- Gene expression after HSW exposure --- p.38
Chapter 3.4.3 --- Ionic mediators of the gene expression --- p.43
Chapter 3.4.4 --- Gene expression after BW exposure --- p.44
Chapter 3.4.5 --- Dynamic changes of the GHR and PRLR in response to salinity changes --- p.45
Chapter 3.4.6 --- Regulation of the gene expression in response to salinity changes --- p.46
Chapter Chapter IV --- Gene expression of sbGHR in liver during salinity changes --- p.49
Chapter 4.1 --- Introduction --- p.49
Chapter 4.1.1 --- Responses of the somatotropic axis to salinity changes in fish --- p.49
Chapter 4.2 --- Materials and methods --- p.52
Chapter 4.3 --- Results --- p.56
Chapter 4.4 --- Discussion --- p.60
Chapter 4.4.1 --- Inhibition of GHR and IGF-I gene expression in liver during HSW exposure --- p.60
Chapter 4.4.2 --- Downregulation of GHR gene expression by hyperosmotic stress --- p.62
Chapter 4.4.3 --- Growth retardation of fish during hyperosmotic environment --- p.64
Chapter Chapter V --- Gene expression studies of sbPRLR in gill organ culture --- p.68
Chapter 5.1 --- Introduction --- p.68
Chapter 5.1.1 --- Functions of gill in fish osmoregulation --- p.68
Chapter 5.1.2 --- Gill culture as a model for osmoregulation studies --- p.69
Chapter 5.2 --- Materials and methods --- p.70
Chapter 5.3 --- Results --- p.71
Chapter 5.4 --- Discussion --- p.73
Chapter Chapter VI --- Regulation of gene expression of sbGHR in liver during hyperosmotic stress: promoter studies --- p.75
Chapter 6.1 --- Introduction --- p.75
Chapter 6.1.1 --- What is a promoter? --- p.75
Chapter 6.1.2 --- Promoter studies of GHR gene --- p.76
Chapter 6.2 --- Materials and methods --- p.78
Chapter 6.3 --- Results --- p.85
Chapter 6.4 --- Discussion --- p.104
Chapter Chapter VII --- General discussion and future perspectives --- p.111
References --- p.117

Style APA, Harvard, Vancouver, ISO itp.

34

Humphries, Alan Wayne. "New challenges for lucerne in southern Australian farming systems : identifying and breeding diverse lucerne germplasm to match these requirements". 2008. http://hdl.handle.net/2440/50451.

Pełny tekst źródła

Streszczenie:

Lucerne is a deep-rooted perennial pasture that is promoted to land managers in southern Australia to mitigate the effects of dryland salinity, a problem of national significance caused by the replacement of native trees and shrubs with annual crops and pastures. In recent years, the acceptance of climate change has provided further rationale for increasing the use of perennial legumes in our farming systems. Perennial legumes have a role in offsetting C02 emissions by sequestering C and N in soil, and provide new, resilient options for future farming in a warmer and more variable climate. This research has focused on evaluating the diverse range of germplasm found in lucerne (Medicago sativa spp.) for a range of attributes in order to determine its compatibility with existing and future farming systems in southern Australia. Regional field evaluation at 8 sites in southern Australia showed that lucerne is a broadly adapted and robust plant. After 3 years, plant density ranged from 2-55 plants / m2 with differences in persistence attributed to tolerance to a combination of stresses including soil acidity, saline and sodic subsoils, drought conditions and persistent heavy grazing. Highly winter-active lucerne (class 9-10) was confirmed to be the most suitable group for short phase rotations in southern Australia, providing grazing is well managed. This germplasm was less persistent than other winter activity groups, but produces more total herbage yield in environments with winter dominant rainfall patterns. Highly winter-active lucerne has poor persistence under continuous grazing, but this may aid in its removal when used in rotation with crops. Winteractive germplasm (class 6-8) was more grazing tolerant and persistent, making it the most suitable group for longer phase rotations (>4 years), or where more flexible grazing management practices are required (i.e. 35 days grazing followed by 35 days recovery). Individual grazing tolerant plants from this group were selected and randomly inter-mated to form new breeder’s lines in the development of a grazing tolerant cultivar. For the first time, the high water-use of a farming system involving wheat overcropped into lucerne is presented. Lucerne over-cropped with wheat used an additional 43-88 mm of water in comparison to continuous wheat at Roseworthy and Katanning respectively. Over-cropping reduced wheat yield by 13-63%, but it can be more efficient in terms of land area to grow lucerne and wheat as a mixture than on separate parcels of land. Very winter-dormant lucerne (class 1-2) appears to be less competitive with winter cereal crops during wheat establishment. It may also be possible to reduce lucerne’s competition with wheat at the critical stage of anthesis, with low spring yielding lucerne varieties identified in this research (SA37908). This group of plants provides excellent potential for the development of high water-use farming systems because they are grazing tolerant and persistent, and have summer forage production and sub-soil water extraction rates that are equivalent to winter active lucerne. The research has been used to identify the perfect ideotype for lucerne in phase farming and over-cropping systems, which can be used to set targets in future breeding programs. The research also highlights current opportunities for the integration of lucerne into southern Australian farming systems to help curb the spread of dryland salinity and reduce the impact of climate change.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1344608
Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008

Style APA, Harvard, Vancouver, ISO itp.

35

Kirkby, S. D. (Stephen Denis). "Managing dryland salinisation with an integrated expert system/geographic information system / S.D. Kirkby". 1994. http://hdl.handle.net/2440/21517.

Pełny tekst źródła

Streszczenie:

Bibliography: leaves 119-218.
xiv, 218 leaves : ill. (some col.), maps (some col.) ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Salt Manager represents the software system developed by this thesis to implement an interactive land classification methodology. An Expert System (ES), a Geographic Information System (GIS), remotely sensed information and a relational database management system (RDBMS) have been utilised to construct the methodology.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geography, 1995

Style APA, Harvard, Vancouver, ISO itp.

Rozprawy doktorskie na temat „Salinity control”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych