Salinisation of the shallow groundwater system has occurred coincident with the development of irrigation in the Coleambally Irrigation Area. Salinisation in irrigation areas has previously been attributed to the evaporative concentration of the water table; however, there are other sources of salt such as the accumulation of rainfall by vegetation and the dry deposition of salt-laden dusts. A significant store of crystalline gypsum, together with high concentrations of Na, Mg and Confidence limit, was found within the previously unsaturated zone of the Upper Shepparton Formation. The salt store was identified both within and outside of the groundwater mound; therefore evaporative concentration of the water table cannot be the source of salt. The transition from regional groundwater quality, as applied as irrigation to the ground surface, to shallow groundwater quality is simply explained by solubilisation of this salt store in the presence of soil CO2. Dating of basal palaeochannel sands indicates that the identified salt store, a profile of only 20 m, was accumulated during the last glacial cycle. Radiocarbon dating indicates that the peak in eluate salinity, at approximately 2 m below ground surface, is between 15,000 and 25,000 years old, coincident with the Last Glacial Maximum. The Last Glacial Maximum was a period of significantly enhanced aridity on the Australian continent. It was also found that the peak in eluate salinity coincided with a bi-modal particle size distribution. The bi-modal signature implies that these sediments were subject to the aeolian accession of dusts. It was found that the contribution of salt from dry deposition of dusts exceeded the contribution from rainfall by at least 1.9 to 11 times during the last glacial cycle. The results of this study imply that salt-laden dusts have, and continue to play an important role in the salinity and sodicity of soils in the Coleambally Irrigation Area and beyond.

Diskette for IBM/PC in pocket on back end paper. Copies of author's previously published articles inserted. Bibliography: leaves 186-207. An evaluation of spatial and temporal variation in composition of soil solutions collected from a hydro-toposequence with seasonally saturated soils ranging from Xeralfs to Aqualfs. The sub-catchment is under native eucalyptus and is formed from granite gneiss. The study shows that mineral weathering under eucalypt vegetation contributes substantially to the quantity of elements measured in soil solution with some aeolian salts. Migration of soil solutions to low lying areas promotes dryland salinity in these landscapes.

No description available.

D. Tech. Engineering: Civil. / Aims to map and model the salinity trends in Vaal Harts irrigation schemes in Jan Kempdorp, Northern Cape Province of South Africa using Landsat SRS, GIS computational tools (IDRIS and ERDAS). The resulted maps and models will aid the effective management of salinity problem and thereby minimizing its occurrence in the future through planning and policy formulation, on the irrigation scheme within the context of environmental sustainability.

Salinisation of the shallow groundwater system has occurred coincident with the development of irrigation in the Coleambally Irrigation Area. Salinisation in irrigation areas has previously been attributed to the evaporative concentration of the water table; however, there are other sources of salt such as the accumulation of rainfall by vegetation and the dry deposition of salt-laden dusts. A significant store of crystalline gypsum, together with high concentrations of Na, Mg and Confidence limit, was found within the previously unsaturated zone of the Upper Shepparton Formation. The salt store was identified both within and outside of the groundwater mound; therefore evaporative concentration of the water table cannot be the source of salt. The transition from regional groundwater quality, as applied as irrigation to the ground surface, to shallow groundwater quality is simply explained by solubilisation of this salt store in the presence of soil CO2. Dating of basal palaeochannel sands indicates that the identified salt store, a profile of only 20 m, was accumulated during the last glacial cycle. Radiocarbon dating indicates that the peak in eluate salinity, at approximately 2 m below ground surface, is between 15,000 and 25,000 years old, coincident with the Last Glacial Maximum. The Last Glacial Maximum was a period of significantly enhanced aridity on the Australian continent. It was also found that the peak in eluate salinity coincided with a bi-modal particle size distribution. The bi-modal signature implies that these sediments were subject to the aeolian accession of dusts. It was found that the contribution of salt from dry deposition of dusts exceeded the contribution from rainfall by at least 1.9 to 11 times during the last glacial cycle. The results of this study imply that salt-laden dusts have, and continue to play an important role in the salinity and sodicity of soils in the Coleambally Irrigation Area and beyond.

Diskette for IBM/PC in pocket on back end paper. / Copies of author's previously published articles inserted. / Bibliography: leaves 186-207. / xvii, 246 leaves : ill., maps ; 30 cm. + 1 computer disk (3 1/2 in.) / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / An evaluation of spatial and temporal variation in composition of soil solutions collected from a hydro-toposequence with seasonally saturated soils ranging from Xeralfs to Aqualfs. The sub-catchment is under native eucalyptus and is formed from granite gneiss. The study shows that mineral weathering under eucalypt vegetation contributes substantially to the quantity of elements measured in soil solution with some aeolian salts. Migration of soil solutions to low lying areas promotes dryland salinity in these landscapes. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1996?

[Truncated abstract] During the last fifty years mathematical models of catchment hydrology have been widely developed and used for hydrologic forecasting, design and water resources management. Most of these models need large numbers of parameters to represent the flow generation process. The model parameters are estimated through calibration techniques and often lead to ‘unrealistic’ values due to structural error in the model formulations. This thesis presents a new strategy for developing catchment hydrology models for representing streamflow and salinity generation processes. The strategy seeks to ‘learn from data’ in order to specify a conceptual framework that is appropriate for the particular space and time scale under consideration. Initially, the conceptual framework is developed by considering large space and time scales. The space and time scales are then progressively reduced and conceptual model complexity systematically increased until ultimately, an adequate simulation of daily streamflow and salinity is achieved. This strategy leads to identification of a few key physically meaningful parameters, most of which can be estimated a priori and with minimal or no calibration. Initially, the annual streamflow data from ten experimental catchments (control and cleared for agriculture) were analysed. The streamflow increased in two phases: (i) immediately after clearing due to reduced evapotranspiration, and (ii) through an increase in stream zone saturated area. The annual evapotranspiration losses from native vegetation and pasture, the ‘excess’ water (resulting from reduced transpiration after land use change), runoff and deep storage were estimated by a simple water balance model. The model parameters are obtained a priori without calibration. The annual model was then elaborated by analysing the monthly rainfall-runoff, groundwater and soil moisture data from four experimental catchments. Ernies (control, fully forested) and Lemon (53% cleared) catchments are located in zone with a mean annual rainfall of 725 mm. Salmon (control, fully forested) and Wights (100% cleared) are located in zone with mean annual rainfall of 1125 mm. Groundwater levels rose and the stream zone saturated area increased significantly after clearing. From analysis of this data it was evident that at a monthly time step the conceptual model framework needed to include a systematic gain/loss to storage component in order to adequately describe the observed lags between peak monthly rainfall and runoff.

Thesis (M.Sc.)--University of Adelaide, Dept. of Geology and Geophysics, 2003. / Includes bibliographical references (leaves 112-115).

SOUSA, Carlos Henrique Carvalho de. Uso integrado de práticas de manejo na recuperação de um solo salino-sódico cultivado com coqueiro. 2012. 124 f. : Tese (doutorado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2012. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-08-03T13:07:43Z No. of bitstreams: 1 2012_tese_chcsousa.pdf: 1731923 bytes, checksum: 3ac2d7171ebc36fa45a7d4cab0cddce0 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-08-03T13:09:15Z (GMT) No. of bitstreams: 1 2012_tese_chcsousa.pdf: 1731923 bytes, checksum: 3ac2d7171ebc36fa45a7d4cab0cddce0 (MD5) / Made available in DSpace on 2016-08-03T13:09:15Z (GMT). No. of bitstreams: 1 2012_tese_chcsousa.pdf: 1731923 bytes, checksum: 3ac2d7171ebc36fa45a7d4cab0cddce0 (MD5) Previous issue date: 2012 / The salt affected soils are known for a long time, however, the scale and intensity have increased considerably, resulting in the expansion of the area degraded by salinity and sodicity. Thus, appropriate management practices to control soil salinity become fundamental mainly aimed at sustainability, as well as being alternative uses and land reclamation. Therefore, the objective of this study was to evaluate the integrated use of management practices in the reclamation of a saline-sodic soil in the irrigated Perimeter Curu-Pentecoste, Ceará, and then carried out an economic viability analysis, using profitability indicators of process of reclamation. The study was conducted in an area cultivated with coconut with 2 years old, with the plants showing delayed development. Initially it was installed a subsurface drainage system consisting of an open drain collector of 135 m, ten side drains of 45 m, composed of pipes Drenoflex DN 65 mm, manta bidim OP-20 and a box of gravel No. 01. The experiment was installed with annual crops between rows of coconut, with treatments being arranged in a randomized block design in a split plot design with four replications during two cycles (2009/2010 and 2010/2011). The plots were formed by the treatments: T1. Subsoiling (S), T2. S + 20 Mg ha-1 gypsum, T3. S + 40 Mg ha-1 of organic matter; T4. S + 10 Mg ha-1 gypsum + 20 Mg ha-1 of organic matter; T5. S + 20 Mg ha-1 gypsum + 40 Mg ha-1 of organic matter. The subplots correspond to two crop rotation systems: cotton-cowpea (AL / FC) and sunflower-cowpea (GI / FC ). The use of subsoiling along with the installation of subsurface drainage system provided an average drawdown of the water table of 0.3 m promoted improvements in soil physical conditions by increasing the hydraulic conductivity. The production of coconut from the first sample taken showed increasing trend from 33.3 fruit / plant / year in 2010/2011 to 152.4 fruits / plant / year in 2011/2012. The results demonstrate that the use of gypsum and organic matter contributed to the decreased levels of salinity and sodicity, and their effects are more evident for reducing sodicity, with gypsum proving more efficient in this process. The highest rates of gypsum and organic matter applied in the treatment T5 promoted greater productivity for sunflower and cowpea. There were no differences in the shoots dry matter of the species within two years of cultivation, however, in the cycle 2010/2011 there was an average increase of 114% (cotton) and 89% (sunflower) relative to 2009/2010 cycle, being an indicative of the progressive recovery of the soil. Statistically significant difference in stomatal conductance, photosynthesis and transpiration were observed only between seasons. Foliar concentrations of Na+ in plants of sunflower and cotton crops were reduced in the second cycle, relative to the first one, especially in the treatments with application of gypsum. The reclamation process showed economic viability at the rate of 2% per year, according to the characteristics of the family farmer assisted by PRONAF. However, the result was only possible with the contribution of coconut production, considering that the production cotton, sunflower and cowpea were not enough to cover the investment. / Os solos afetados por sais são conhecidos há muito tempo, no entanto, sua extensão e intensidade têm aumentado consideravelmente, resultando na expansão da área degradada por salinidade e sodicidade. Assim, práticas de manejo adequadas para controlar a salinidade dos solos tornam-se fundamentais principalmente visando à sustentabilidade, além de constituírem alternativas de uso e recuperação do solo. Portanto, o objetivo deste trabalho foi avaliar o uso integrado de práticas de manejo na recuperação de um solo salino-sódico no Perímetro Irrigado Curu-Pentecoste, Ceará, e em seguida proceder uma análise de viabilidade econômica, utilizando indicadores de rentabilidade do processo de recuperação. O estudo foi desenvolvido em uma área cultivada com coqueiro com cerca de 2 anos de idade e que se encontrava com desenvolvimento bastante reduzido. Inicialmente foi instalado um sistema de drenagem subterrâneo constituído de um dreno coletor aberto de 135 m, dez drenos laterais de 45 m, compostos por tubos drenoflex DN 65 mm, manta bidim OP-20 e uma caixa de brita n° 01. O experimento com culturas anuais foi instalado entre as fileiras de coqueiro, com os tratamentos sendo dispostos em um delineamento em blocos casualizados, em parcelas subdivididas, com quatro repetições, durante dois ciclos (2009/2010 e 2010/2011). As parcelas foram formadas pelos tratamentos: T1. Subsolagem (S); T2. S + 20 Mg ha-1 de gesso; T3. S + 40 Mg ha-1 de matéria orgânica; T4. S + 10 Mg ha-1 de gesso + 20 Mg ha-1 de matéria orgânica; T5. S + 20 Mg ha-1 de gesso + 40 Mg ha-1 de matéria orgânica, e as subparcelas corresponderam às rotações culturais algodão-feijão-de-corda (AL/FC) e girassol-feijão-decorda (GI/FC). A utilização da subsolagem juntamente com a instalação do sistema de drenagem subterrâneo proporcionou um rebaixamento médio do lençol freático de 0,3 m e promoveu melhorias nas condições físicas do solo aumentando a condutividade hidráulica. A produção do coqueiro desde a primeira colheita realizada apresentou evolução crescente passando de 33,3 fruto/planta/ano em 2010/2011 para 152,4 frutos/planta/ ano em 2011/2012. Os resultados demonstram que o emprego dos corretivos químicos e orgânicos contribuiu para a diminuição dos níveis de salinidade e sodicidade do solo, sendo seus efeitos mais evidenciados para redução da sodicidade, com o gesso se mostrando mais eficiente nesse processo. As maiores doses de gesso e matéria orgânica aplicadas no tratamento T5 promoveram a maior produtividade do girassol e do feijão-de-corda. Não se observou diferenças na produção de matéria seca da parte aérea entre as espécies nos dois anos de cultivo; no entanto, no ciclo 2010/2011 observou-se um aumento médio de 114% (algodão) e 89% (girassol) na produção de matéria seca, em relação ao ciclo 2009/2010, sendo um indicativo da recuperação progressiva do solo. Observaram diferenças estatísticas nas medições de condutância estomática e das taxas de fotossíntese e de transpiração apenas entre épocas de medições. Os teores foliares de Na+ nas plantas de girassol e algodão foram reduzidos de um cultivo para outro, principalmente nos tratamentos com aplicação de gesso. O processo de recuperação apresentou viabilidade econômica à taxa de juros de 2% ao ano, conforme características do agricultor familiar assistido pelo PRONAF. No entanto, o resultado só foi possível com a contribuição da produção do coqueiro, haja vista que produção do algodão, girassol e feijão-de-corda não foram suficientes para amortizar os investimentos.

The diploma thesis with name “Monitoring the Impact of Simulated Rainfall on Soil with Flushing Water by EIS Method” deals with the problems of soil degradation due to salinization and sodification in consequence of infiltration of flushing waters from roads during winter maintenance. This experiment was realized in laboratories of the Institute of water structures of the Faculty of Civil engineering at Brno University of Technology and researched the influence of simulated rainfall on degraded soil by method of electrical impedance spectrometry (EIS). The thesis follows the solution of projects in international EUREKA program.