Thesis (Ph.D.)--University of Melbourne, Institute of Land and Food Resources, 1999. / Typescript (photocopy). Includes bibliographical references.

Dryland salinity is a major and expanding threat to agricultural land in Australia. Animal production from forages grown on saline land is perhaps its most promising economic use. Glycophytic forage legumes have been evaluated under saline conditions mainly for agronomic characteristics and, to a lesser extent, for nutritive quality to animals. Plant growth and its nutritive quality are interrelated, but a decline in yield in response to salinity may be associated with effects on the chemical constituents of the plant since soil salinity affects plant metabolism. This research aimed to investigate changes in the components of yield and nutritive value of two legumes species. Lucerne ( Medicago sativa ) and Melilotus ( Melilotus albus ) were exposed to different levels of NaCl in the range of 0 to 110 mM NaCl. The research tested the hypothesis that the components of plant nutritive value are not as sensitive to salinity as shoot biomass production since the adaptive mechanisms of the plant lessen harmful effects of the salts. For both plant species, salinity decreased leaf and stem dry matter production, but increased leaf - to - stem ratio. In addition, salinity resulted in earlier flowering in Melilotus. Mineral composition was the most sensitive component of forage quality. Calculated sodium chloride concentrations were up to 125 g / kg DM in lucerne and 39 g / kg DM in Melilotus when irrigated with 110 mM NaCl. The concentrations of calcium and magnesium decreased in both species and approached the marginal range for animal production. Zinc concentration also decreased while potassium decreased in stems of lucerne only. The digestible organic matter ( DOMD ) in response to salinity varied between species. At the highest salt concentration, the whole shoot ( i.e., leaf and stem ) of lucerne decreased up to 4 percentage units while Melilotus increased by 6 percentage units. In lucerne, DOMD was influenced by a high concentration of soluble ash in leaf and stem and, in Melilotus, by an increase in the organic matter content of leaf and a reduction in lignin concentration in stem, which favoured higher digestibility. These results were supported by a histological study in which an increase in starch in Melilotus leaf, and a lower proportion of xylem in relation to parenchyma in stems, was measured. Crude protein concentration was not compromised and, in relation to Melilotus, coumarin concentration did not increase with salinity. In conclusion, the reduction in DM production of species with similar salt tolerance does not necessarily correspond to an equivalent reduction in nutritive value. This research represents the most detailed study into effects of salinity on glycophytic forage legumes. Results show that while some aspects of forage quality ( e.g., minerals composition and energy ) are strongly influenced by salinity, other aspects ( e.g., protein ) remain relatively unaffected. These findings have implications for development of productive grazing systems on saline agricultural land. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.

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

Dryland salinity is a major and expanding threat to agricultural land in Australia. Animal production from forages grown on saline land is perhaps its most promising economic use. Glycophytic forage legumes have been evaluated under saline conditions mainly for agronomic characteristics and, to a lesser extent, for nutritive quality to animals. Plant growth and its nutritive quality are interrelated, but a decline in yield in response to salinity may be associated with effects on the chemical constituents of the plant since soil salinity affects plant metabolism. This research aimed to investigate changes in the components of yield and nutritive value of two legumes species. Lucerne ( Medicago sativa ) and Melilotus ( Melilotus albus ) were exposed to different levels of NaCl in the range of 0 to 110 mM NaCl. The research tested the hypothesis that the components of plant nutritive value are not as sensitive to salinity as shoot biomass production since the adaptive mechanisms of the plant lessen harmful effects of the salts. For both plant species, salinity decreased leaf and stem dry matter production, but increased leaf - to - stem ratio. In addition, salinity resulted in earlier flowering in Melilotus. Mineral composition was the most sensitive component of forage quality. Calculated sodium chloride concentrations were up to 125 g / kg DM in lucerne and 39 g / kg DM in Melilotus when irrigated with 110 mM NaCl. The concentrations of calcium and magnesium decreased in both species and approached the marginal range for animal production. Zinc concentration also decreased while potassium decreased in stems of lucerne only. The digestible organic matter ( DOMD ) in response to salinity varied between species. At the highest salt concentration, the whole shoot ( i.e., leaf and stem ) of lucerne decreased up to 4 percentage units while Melilotus increased by 6 percentage units. In lucerne, DOMD was influenced by a high concentration of soluble ash in leaf and stem and, in Melilotus, by an increase in the organic matter content of leaf and a reduction in lignin concentration in stem, which favoured higher digestibility. These results were supported by a histological study in which an increase in starch in Melilotus leaf, and a lower proportion of xylem in relation to parenchyma in stems, was measured. Crude protein concentration was not compromised and, in relation to Melilotus, coumarin concentration did not increase with salinity. In conclusion, the reduction in DM production of species with similar salt tolerance does not necessarily correspond to an equivalent reduction in nutritive value. This research represents the most detailed study into effects of salinity on glycophytic forage legumes. Results show that while some aspects of forage quality ( e.g., minerals composition and energy ) are strongly influenced by salinity, other aspects ( e.g., protein ) remain relatively unaffected. These findings have implications for development of productive grazing systems on saline agricultural land. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.

The dynamics of salt accumulation in the soil over time is one of major important information input needed for decision-making in regard to irrigate with saline water. As all waters contain some dissolved salts, during the irrigation these salts tend to concentrate in the soil causing depressed plant growth. Saline irrigation water, low soil permeability, inadequate drainage conditions, low rainfall and poor irrigation management all contribute to the tendency of salt accumulation in the soil. The principal salt accumulation problem of economic importance arises when non-saline soils become saline as result of irrigation. The dynamics of salt accumulation in this study, is based on the model for tracing salt distribution in the soil affected by the quantity and quality of irrigation water, amount of nitrogen and initial soil salinity. To verify the model for tracing salt distribution in the soil and to statistically estimate a crop-production function and soil salinity relation, agronomic data were used from field experiment conducted at the University of Arizona, Maricopa Agricultural Center (MAC), during the 1985 growing season and that utilized cotton variety Delta Pine 61. From the point of view of the response functions and salt accumulation in the soil, many assumptions were made before formulating the models. Results show that (1) no conclusions could be drawn with respect to the model of salt accumulation in the soil, (2) in the case of yield production function and soil salinity relation, the water quantity coeffient had an absolute value greater than one, (3) water quality and nitrogen coefficients had an absolute value less than one, (4) initial soil salinity coefficient had negative value, (5) looking for the best combination amoung the variables inputs, the marginal rate of substitution was greater than the ratio of prices, (6) the time path for soil salinity converge to a steady state conditions, and (7) the profitability of cotton irrigated with drip system is sensitive to yield increases and increases in the price of cotton.

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

Thesis (Ph.D.)--Murdoch University, 2008. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references (leaves 123-154).

Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Made available in DSpace on 2014-06-11T19:26:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-11Bitstream added on 2014-06-13T20:34:06Z : No. of bitstreams: 1 yamasaki_mt_me_bauru.pdf: 2126849 bytes, checksum: 4896e264bafeff1d70577b538318f03e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A resistividade elétrica vem sendo somada junto aos estudos de investigação geotécnica devido ao seu apelo ambiental, visto que esta técnica se dá por meio da imposição de um fluxo de corrente elétrica em uma amostra de solo, permitindo-se avaliar as condições geológicas locais por um método não destrutivo. A obtenção dessa medida vem sendo somada aos estudos de investigação geotécnica devido ao seu apelo ambiental, otimizando as amostragens e permitindo a avaliação das condições geológicas locais por meio de um método não destrutivo. Dessa maneira, o objetivo dessa dissertação de mestrado é avaliar, em laboratório, o comportamento da resistividade elétrica variando-se o teor de salinidade no fluido de percolação em dois solos tropicais: um arenoso, sedimentar, característico da região de Bauru, e outro argiloso, resultado do intemperismo do Diabásio, proveniente do município de Piracicaba. As análises foram realizadas utilizando-se resultados, dos ensaios de caracterização, compactação, permeabilidade e curva de retenção. o teor de salinidade do fluido foi considerado, tanto na compactação, como na percolação em três concentrações: água destilada, 250 ppm e 500 ppm de NaCI, além de abastecimento, controlando-se o teor de umidade, a compactação, o índice de vazios e o grau de saturação. Os resultados mostraram-se que a resistividade elétrica tende a ser constante no ramo úmido da curva de compactação e também quando o grau de saturação está acima de 80%. Notou-se também que a curva de resistividade versus sucção pode ser divida em dois trechos: o primeiro corresponde às baixas sucções, com a continuidade da água nos poros e resistividade menores; o segundo trecho, que se inicia na primeira entrada de dar, conduz a um nítido aumento nos valores de... / The electrical resitivity of a homogeneous material could be defined as the measurements of the difficult of crossing of the electrical current and it depends of the dimension and type of material. However, when that material is soil, composed by three phases (solid, liquid and gas), this measure is influenced by several factors that could be controlled in laboratory tests. The electrical resistivity has been used geotechnical research studies since this technique improve the sampling of environmental works and allowing the evaluation of local geological conditions through a non-destructive method. Thus, the goal of the study was evaluate the behavior of electrical resistivity of two tropical soils varying the salinity concentration in the percolation fluid: a sandy sediment, characteristic of the Bauru city; a clayey soil, Weathered of Diabase from Piracicaba City. Results of soil mechanics laboratory tests as characterization tests, compaction, permeability and soil-water retention curve were used in the analyses. In both, compaction and permeability tests, the procedure were carried out varying the fluid salinity: distilled water, water supply; 250ppm and 500ppm of NaCi. The moisture content, compaction energy, void ratio and degree of saturation. The tests results showed the rsistivity values tend to be constant in the wet density curve and when the degree of saturation is above 80%. It was also noted that the curve of resistivity suction could be divided into two segments: the first corresponds to low suctions where there is continuity of water in the porous leading to low resistivity values; the second segment begins in the first air entrance, with discountinuous state of pore-water and sa sharphy increase in the resistivity values. The formation factors (FF) were obtained during the permeability tests: 7,5 to the sandy soil and... (Complete abstract click electronic access below)

Made available in DSpace on 2016-06-02T18:55:24Z (GMT). No. of bitstreams: 1 4855.pdf: 1701786 bytes, checksum: f886dd37262de3e99d2829c84764b9bf (MD5) Previous issue date: 2013-02-01 / Universidade Federal de Minas Gerais / The concern in developing strategies to solve the water scarcity problem is growing and actual. As a big consumer of the available fresh water, agriculture is the activity with the biggest potential for applying of water reuse. This study set up in CCA/UFSCar evaluated, on laboratory conditions, the physical and chemical properties of a soil irrigated with treated wastewater after the application of a water sheet corresponding to five cycles of lettuce s growth (Lactuca sativa, L.) and in a greenhouse, evaluated the sanitary characteristics and mass of the Elisa type lettuce and the physical, chemical and microbiological characteristics of the soil after the cultivation with treated wastewater, comes from the wastewater treatment plant from the university. In the laboratory experiment, eighteen undisturbed soil samples were coupled in a constant head permeameter and received a water sheet corresponding to five cycles of lettuce s growth, 0.58, 1.16, 1.74, 2.32 and 2.9 L of water for each cycle. The soil samples were distributed in five groups that received treated wastewater and one control group that received distilled water. Soil samples were collected to analyze the granulometry, saturated hydraulic conductivity (ksat), exchangeable sodium percentage (ESP) and soil fertility. Treated wastewater and distilled water leached samples were collected to analyze the electrical conductivity, sodium adsorption ratio (SAR), turbidity, pH, sodium, potassium, magnesium, phosphorus, calcium and nitrate. In a greenhouse, two cycles of Elisa lettuce were cultivated with two treatments (treated wastewater and supply water) with four repetitions. After the harvest of the lettuce, soil samples were collected to analyze granulometry, density, ksat, and soil fertility, total coliforms, Escherichia coli and heterotrophic. The harvested lettuces were analyzed for total coliforms, Escherichia coli and chemical analysis of plant tissue. In laboratory, there was an increase of ESP and the concentration of phosphorus and sodium on soil after the application of the water sheet. There wasn t significant difference on the physical properties of soil, turbidity and SAR. In a greenhouse, there wasn t significant difference between the treatments on nutrients absorption of lettuces cultivated, but the weight of lettuces irrigated with wastewater was 100% greater than the lettuces irrigated with supply water on the second cycle. It was not detected the presence of Esherichia coli on the cultivated lettuces, but there was total coliforms contamination, that presents a risk of contamination to the consumer. The irrigation with treated wastewater increased the nutrients on soil and the SAR indicated a soil salinization risk. The treated wastewater does not cause damage on the physical properties of soil. / A preocupação em desenvolver estratégias para minimizar o problema da escassez de água é crescente e atual. Como grande consumidora da água doce disponível, a agricultura é o setor com maior potencial de aplicação da água de reúso. Este trabalho desenvolvido no CCA/UFSCar avaliou, em laboratório, as propriedades físicas e químicas do solo irrigado com água de reúso tratada após aplicação de lâmina de irrigação correspondente ao cultivo de cinco ciclos de alface (Lactuca sativa L.) e, em casa de vegetação, as características sanitárias e a massa da cultura de alface Elisa e as características físicas, químicas e microbiológicas do solo após o cultivo com água de reúso, proveniente da estação de tratamento de esgoto da universidade. No experimento em laboratório, dezoito amostras indeformadas de solo foram acopladas em permeâmetro de carga constante e receberam lâmina de irrigação referente a cinco ciclos de cultivo de alface, 0,58, 1,16, 1,74, 2,32 e 2,9 L de água para cada ciclo. As amostras foram divididas em cinco grupos que receberam água de reúso e um grupo controle, que recebeu água destilada. Amostras de solo foram coletadas para determinar a granulometria, condutividade hidráulica saturada (ksat), porcentagem de sódio trocável (PST) e fertilidade do solo. Amostras da água de reúso e água destilada lixiviadas foram coletadas para determinar a condutividade elétrica, razão de adsorção de sódio (RAS), turbidez, pH, sódio, potássio, magnésio, fósforo, cálcio e nitrato. Em casa de vegetação, dois ciclos de alface "Elisa" foram cultivados com dois tratamentos (água de reúso e de abastecimento) com quatro repetições. Após a colheita, amostras de solo foram coletadas para determinar a granulometria, densidade, ksat, fertilidade do solo, coliformes totais, Escherichia coli e heterotróficos. Nas alfaces colhidas foram determinados os coliformes totais, Escherichia coli e análise química do tecido vegetal. Em laboratório, houve aumento da PST e teor de fósforo e sódio no solo após aplicação das lâminas de irrigação. Não houve diferença significativa nas propriedades físicas do solo, turbidez e RAS. Na casa de vegetação, não houve diferença significativa entre os tratamentos na absorção de nutrientes pelas alfaces cultivadas, porém, a massa das alfaces irrigadas com água de reúso foi 100% maior que a das alfaces irrigadas com água de abastecimento no segundo ciclo. Não foi detectada presença de Escherichia coli nas alfaces cultivadas, mas houve concentração de coliformes totais, o que representa risco de contaminação ao consumidor. A irrigação com água de reúso aumentou o teor de nutrientes no solo e a RAS indicou risco de salinização. A água de reúso não causou alterações nas propriedades físicas do solo.