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1
Zhang, Z., H. Hu, F. Tian, X. Yao und M. Sivapalan. „Groundwater Dynamics under Water Saving Irrigation and Implications for Sustainable Water Management in an Oasis: Tarim River Basin of Western China“. Hydrology and Earth System Sciences Discussions 11, Nr. 2 (10.02.2014): 1777–820. http://dx.doi.org/10.5194/hessd-11-1777-2014.
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Abstract. Water is essential for life. Specifically in the oases of inland arid basins, water is a critically limited resource, essential for the development of socio-economy and sustainability of eco-environmental systems. Due to the unique hydrological regime present in arid oases, a moderate groundwater table is the goal of sustainable water management. A shallow water table induces serious secondary salinization and collapse of agriculture, while a deep water table causes deterioration of natural vegetation. From the hydrological perspective, the exchange flux between unsaturated vadose zone and groundwater reservoir is a critical link to understand regional water table dynamics. This flux is substantially influenced by anthropogenic activities. In Tarim River Basin of western China, where agriculture consumes over 90% of available water resources, the exchange flux is influenced strongly by irrigation. Recently, mulched drip irrigation, a very advanced water-saving irrigation method, has been widely applied in the Tarim River Basin, which greatly impacted the exchange flux and thus the regional groundwater dynamics. Capitalizing on recent progress in evaporation measurement techniques, we can now close the water balance and directly quantify the exchange flux at the field scale, thus gain a better understanding of regional groundwater dynamics. In this study, comprehensive observations of water balance components in an irrigated cropland were implemented in 2011 and 2012 in a typical oasis within Tarim River Basin. The water balance analysis showed that the exchange flux and groundwater dynamics were significantly altered by the application of water-saving irrigation. The exchange flux is mostly downward (310.5 mm yr−1), especially during drip irrigation period and spring flush period, while the upward flux is trivial (−16.1 mm yr−1) due to the moderate groundwater table depth (annual average depth 2.9 m). Traditional secondary salinization caused by intense phreatic evaporation (fed by upward exchange flux) is alleviated. However, a new form of secondary salinization may be introduced unwittingly if there is lack of water for periodic flushing, especially when brackish water is used in the irrigation. Furthermore, the water saved via drip irrigation has been used in further growth of irrigated lands instead of supporting ecological system. This would lead to increasing risk of eco-environmental degradation and calls for improved governance schemes. The insights gained from this study can be potentially applied to other arid inland areas (e.g., central Asia, sub-Saharan Africa) which face similar water shortages and human development problems.
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Zhang, Z., H. Hu, F. Tian, X. Yao und M. Sivapalan. „Groundwater dynamics under water-saving irrigation and implications for sustainable water management in an oasis: Tarim River basin of western China“. Hydrology and Earth System Sciences 18, Nr. 10 (07.10.2014): 3951–67. http://dx.doi.org/10.5194/hess-18-3951-2014.
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Abstract. Water is essential for life. Specifically in the oases of inland arid basins, water is a critically limited resource, essential for the development of the socio-economy and the sustainability of eco-environmental systems. Due to the unique hydrological regime present in arid oases, a moderate groundwater table is the goal of sustainable water management. A shallow water table induces serious secondary salinization and collapse of agriculture, while a deep water table causes deterioration of natural vegetation. From the hydrological perspective, the exchange flux between the unsaturated vadose zone and groundwater reservoir is a critical link to understanding regional water table dynamics. This flux is substantially influenced by anthropogenic activities. In the Tarim River basin of western China, where agriculture consumes over 90% of available water resources, the exchange flux between the unsaturated vadose zone and groundwater reservoir is influenced strongly by irrigation. Recently, mulched drip irrigation, a sophisticated water-saving irrigation method, was widely applied in the Tarim River basin, which greatly impacted the exchange flux and thus the regional groundwater dynamics. Capitalizing on recent progress in evaporation measurement techniques, we can now close the water balance and directly quantify the exchange flux at the field scale, thus gaining a better understanding of regional groundwater dynamics. In this study, comprehensive observations of water balance components in an irrigated cropland were implemented in 2012 and 2013 in a typical oasis within the Tarim River basin. The water balance analysis showed that the exchange flux and groundwater dynamics were significantly altered by the application of water-saving irrigation. The exchange flux at the groundwater table is mostly downward (310.5 mm year−1), especially during drip irrigation period and spring flush period, while the upward flux is trivial (16.1 mm year−1) due to the moderate groundwater table depth (annual average depth 2.9 m). Traditional secondary salinization caused by intense phreatic evaporation (fed by upward exchange flux) is alleviated. However, a new form of secondary salinization may be introduced unwittingly if there is lack of water for periodic flushing, especially when brackish water is used in the irrigation. Furthermore, the water saved via drip irrigation has been used in further growth of irrigated lands instead of supporting the ecological system. This could lead to an increased risk of eco-environmental degradation and calls for improved governance schemes. The insights gained from this study can be potentially applied to other arid inland areas (e.g., central Asia) which face similar water shortages and human development problems.
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Martano, P., C. Elefante und F. Grasso. „Ten years water and energy surface balance from the CNR-ISAC micrometeorological station in Salento peninsula (southern Italy)“. Advances in Science and Research 12, Nr. 1 (16.06.2015): 121–25. http://dx.doi.org/10.5194/asr-12-121-2015.
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Abstract. Data of surface-atmosphere energy and water transfer from a ten years (2003–2013) period of activity of the ISAC-Lecce micrometeorological station (http://www.basesperimentale.le.isac.cnr.it) have been analyzed: to the authors' knowledge this is the first decadal data set of surface-atmosphere transfer in Salento peninsula. The surface energy budget shows a tendency to a positive bias possibly due to several reasons that require more investigations. Some suitable indices related to the surface water balance, such as the precipitation intensity, the aridity index and the ground water infiltration fraction have been calculated. Possible trends of these annual averages in the decadal period are considered, also taking into account the statistical uncertainty associated to measurement errors and missing data. The results indicate a significant increasing in the precipitation intensity together with an experimental evidence of increasing of the ground water infiltration in the measurement area, that is in agreement with recent estimations for the whole Salento peninsula. On the other hand, recent studies show that seawater intrusion and salinization of the deep underground aquifer keep increasing in the same period.
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Soncela, Rosimaldo, Silvio Cesar Sampaio, Marcio Antonio Vilas Boas, Maria Hermínia Ferreira Tavares, Claudinei Fonseca Souza und Adriana Smanhotto Soncela. „Electrical conductivity of soil irrigated with swine wastewater estimated by time-domain reflectometry¹“. Revista Brasileira de Ciência do Solo 35, Nr. 4 (August 2011): 1293–300. http://dx.doi.org/10.1590/s0100-06832011000400023.
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Wastewater application to soil is an alternative for fertilization and water reuse. However, particular care must be taken with this practice, since successive wastewater applications can cause soil salinization. Time-domain reflectometry (TDR) allows for the simultaneous and continuous monitoring of both soil water content and apparent electrical conductivity and thus for the indirect measurement of the electrical conductivity of the soil solution. This study aimed to evaluate the suitability of TDR for the indirect determination of the electrical conductivity (ECse) of the saturated soil extract by using an empirical equation for the apparatus TDR Trase 6050X1. Disturbed soil samples saturated with swine wastewater were used, at soil proportions of 0, 0.45, 0.90, 1.80, 2.70, and 3.60 m³ m-3. The probes were equipped with three handmade 0.20 cm long rods. The fit of the empirical model that associated the TDR measured values of electrical conductivity (EC TDR) to ECse was excellent, indicating this approach as suitable for the determination of electrical conductivity of the soil solution.
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Bonamico, Margherita, Paola Tuccimei, Lucia Mastrorillo und Roberto Mazza. „Freshwater–Saltwater Interactions in a Multilayer Coastal Aquifer (Ostia Antica Archaeological Park, Central ITALY)“. Water 13, Nr. 13 (04.07.2021): 1866. http://dx.doi.org/10.3390/w13131866.
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An integrated research approach consisting of hydrogeologic and geochemical methods was applied to a coastal aquifer in the Ostia Antica archaeological park, Roma, Italy, to describe freshwater–saltwater interactions. The archaeological park of Ostia Antica is located on the left bank of the Tevere River delta which developed on a morphologically depressed area. The water monitoring program included the installation of multiparametric probes in some wells inside the archaeological area, with continuous measurement of temperature, electrical conductivity, and water table level. Field surveys, water sampling, and major elements and bromide analyses were carried out on a seasonal basis in 2016. In order to understand the detailed stratigraphic setting of the area, three surface boreholes were accomplished. Two distinct circulations were identified during the dry season, with local interaction in the rainy period: an upper one within the archaeological cover, less saline and with recharge inland; and a deeper one in the alluvial materials of Tevere River, affected by salinization. Oxygen and carbon isotopic signature of calcite in the sediments extracted from the boreholes, along with major elements and Br concentration, allowed us to recognize the sources of salinity (mainly, local interaction with Roman salt pans and agricultural practices) and the processes of gas–water–rock interaction occurring in the area. All these inferences were confirmed and strengthened by PCA analysis of physicochemical data of groundwater.
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Piotrowski, Joseph, Johan Alexander Huisman, Uri Nachshon, Andreas Pohlmeier und Harry Vereecken. „Gas Permeability of Salt Crusts Formed by Evaporation from Porous Media“. Geosciences 10, Nr. 11 (25.10.2020): 423. http://dx.doi.org/10.3390/geosciences10110423.
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Soil salinization in irrigated croplands is a key factor in soil degradation and directly affects plant growth and soil hydrological processes such as evaporation and infiltration. In order to support the development of appropriate irrigation strategies, it is important to understand the impact of salt crusts that form during evaporation from saline soils on water flow. The determination of the effective hydraulic properties of salt crusts that control evaporation is still a challenge due to the lack of suitable measurement techniques. In this study, we propose an approach using gas flow to determine the permeability of salt crusts obtained from evaporation of unsaturated saline solutions of three different salt types and investigate the impact of the crust permeability on evaporation. For this, sand columns saturated with initial solutions of sodium chloride (NaCl), magnesium sulfate (MgSO4), and sodium sulfate (Na2SO4) at concentrations corresponding to 33% of the solubility limit were prepared and allowed to evaporate in order to induce crust formation. The results demonstrated that the intrinsic permeability of the dry salt crusts was similar for the different types of salts (≈4 × 10−12 m2), whereas the evaporation of the prepared columns differed significantly. We conclude that the intrinsic crust permeability only partly explains the impact of the crust on evaporation. Other effective crust properties such as porosity or unsaturated hydraulic properties may provide additional information on how evaporation is affected by salt crust formation.
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Wilson, Clyde, Xuan Liu, Scott M. Lesch und Donald L. Suarez. „Growth Response of Major U.S. Cowpea Cultivars. I. Biomass Accumulation and Salt Tolerance“. HortScience 41, Nr. 1 (Februar 2006): 225–30. http://dx.doi.org/10.21273/hortsci.41.1.225.
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Over the last several years, there has been increasing interest in amending the soil using cover crops, especially in desert agriculture. One cover crop of interest in the desert Coachella Valley of California is cowpea [Vigna unguiculata (L.) Walp.]. Cowpea is particularly useful in that as an excellent cover crop, fixing abundant amounts of nitrogen which can reduce fertilizer costs. However, soil salinity problems are of increasing concern in the Coachella Valley of California where the Colorado River water is a major source of irrigation water. Unfortunately, little information is available on the response of cowpea growth to salt stress. Thus, we investigated the growth response of 12 major cowpea cultivars (`CB5', `CB27', `CB46', `IT89KD-288', `IT93K-503-1', `Iron Clay', `Speckled Purple Hall', `UCR 134', `UCR 671', `UCR 730', `8517', and `7964') to increasing salinity levels. The experiment was set up as a standard Split Plot design. Seven salinity levels ranging from 2.6 to 20.1 dS·m–1 were constructed, based on Colorado River water salt composition, to have NaCl, CaCl2 and MgSO4 as the salinization salts. The osmotic potential ranged from –0.075 to –0.82 MPa. Salt stress began 7 days after planting by adding the salts into irrigating nutrient solution and ended after 5 consecutive days. The plants were harvested during flowering period for biomass measurement (53 days after planting). Data analysis using SAS analysis of variance indicated that the salinity in the range between 2.6 and 20.1 dS·m–1 significantly reduced leaf area, leaf dry weight, stem dry weight and root dry weight (P ≤ 0.05). We applied the data to a salt-tolerance model, log(Y) = a1 + a2X + a3X2, where Y represents biomass, a1, a2 and a3 are empirical constants, and X represents salinity, and found that the model accounted for 99%, 97%, 96%, 99%, and 96% of salt effect for cowpea shoot, leaf area, leaf dry weight, stem dry weight and root dry weight, respectively. We also found significant differences (P ≤ 0.05) of each biomass parameter among the 12 cultivars and obtained different sets of the empirical constants to quantitatively describe the response of each biomass parameter to salinity for individual cowpea cultivars. Since a significant salt × cultivar interaction effect (P ≤ 0.05) was found on leaf area and leaf dry weight, we concluded that salt tolerance differences exist among the tested cultivars.
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Baram, S., Z. Ronen, D. Kurtzman, C. Külls und O. Dahan. „Desiccation-crack-induced salinization in deep clay sediment“. Hydrology and Earth System Sciences 17, Nr. 4 (22.04.2013): 1533–45. http://dx.doi.org/10.5194/hess-17-1533-2013.
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Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water content and on the chemical and isotopic composition of the sediment and pore water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ~ 3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl−) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a desiccation-crack-induced salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.
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Baram, S., Z. Ronen, D. Kurtzman, C. Küells und O. Dahan. „Desiccation-crack-induced salinization in deep clay sediment“. Hydrology and Earth System Sciences Discussions 9, Nr. 11 (21.11.2012): 13155–89. http://dx.doi.org/10.5194/hessd-9-13155-2012.
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Abstract. A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water-content and on the chemical and isotopic composition of the sediment and pore-water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ∼3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl-) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a Desiccation-Crack-Induced Salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.
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Faye, Waly, Awa Niang Fall, Didier Orange, Frédéric Do, Olivier Roupsard und Alioune Kane. „Climatic variability in the Sine-Saloum basin and its impacts on water resources: case of the Sob and Diohine watersheds in the region of Niakhar“. Proceedings of the International Association of Hydrological Sciences 383 (16.09.2020): 391–99. http://dx.doi.org/10.5194/piahs-383-391-2020.
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Abstract. Local peoples from Niakhar in the Senegalese peanut basin highlight a dramatic increase of water access problems due to marked rainfall deficits and salinization of surface and ground water resources. The chemical quality of groundwaters is often critical because of the salinization process, whereas water surfaces, which should be used in such situations, are up early. More and more, lowlands and rivers beds are pervaded by salt crusts. Then the salinization of wells is increasing, leading to the extension of tans (salty of acidified soils). To study the impacts of climatic pejoration on the agroecosystems and on the living conditions of the populations, we carried out the analysis of the time series of the precipitations with daily and annual time steps from 1950 to 2015 on 6 meteorological stations, in situ measurements on 78 wells for an area of 311 km2, as well as local population interviews and field observation. The results confirm an important climatic break in the region in 1970. The long dry period, from 1970 to 2009, has increased the annual rain variability, decreased the number of rainy days per year. We confirm a real and large extension of well salinization, and salt crusting in the lowlands and the riverbeds. From the local people, it seems the process of degradation of the aquifers continues to progress from a large tidal event in 1984. The rainfall increase noted in the last decade does not seem to be enough to reverse the trend and to ensure both the rise of the piezometric level of the aquifers and the desalinization of surface and ground waters.
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Duarte, Sérgio Nascimento, Nildo Da Silva Dias und José Francisco Teles Filho. „RECUPERAÇÃO DE UM SOLO SALINIZADO DEVIDO A EXCESSO DE FERTILIZANTES EM AMBIENTE PROTEGIDO.“ IRRIGA 12, Nr. 3 (17.09.2007): 422–28. http://dx.doi.org/10.15809/irriga.2007v12n3p422-428.
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RECUPERAÇÃO DE UM SOLO SALINIZADO DEVIDO A EXCESSO DE FERTILIZANTES EM AMBIENTE PROTEGIDO. Sergio Nascimento Duarte1; Nildo da Silva Dias2; José Francisco Teles Filho11Departamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, snduarte@esalq.usp.br2Departamento de Engenharia Ambiental, Universidade Federal Rural do Semi-Árido, Mossoró, RN 1 RESUMO O aumento da salinidade em ambientes protegidos da região Sudeste do Brasil dá-se, geralmente, em função do excesso de fertilizantes aplicados via água de irrigação; portanto, é necessário que medidas preventivas e corretivas sejam tomadas, pois o uso intensivo de adubação, a falta de chuvas e a contínua evaporação da água do solo podem aumentar o teor de sais na solução do solo. Assim, o objetivo deste trabalho foi avaliar a viabilidade da utilização da fórmula de Hoffman (1980) para o cálculo da lâmina de lavagem de recuperação de solos salinos. O experimento foi desenvolvido em duas estufas plásticas na área experimental do Departamento de Engenharia Rural da Escola Superior de Agricultura “Luiz de Queiroz”, Piracicaba, SP. O estudo foi feito aproveitando-se de um experimento anterior em que o solo das parcelas experimentais passou por um processo de salinização artificial mediante adição de fertilizantes. Foram utilizadas 20 parcelas experimentais com salinidade inicial da camada de 0-40 cm entre 2 e 6 dS m-1, avaliados previamente por meios da medição da CEes. Procurou-se aplicar lâminas de lavagem, calculadas individualmente para cada nível da salinidade, com o intuito de abaixar a concentração de sais da solução do solo para níveis próximos a 1 dS m-1. Os resultados obtidos revelaram que a lâmina de lavagem foi subestimada, havendo a necessidade de se aplicar um maior volume de água. UNITERMOS: salinidade, lixiviação, condutividade elétrica. DUARTE, S. N.; DIAS, N. da S.; TELES FILHO. J. F. RECOVERY OF A SALINIZED SOIL DUE TO EXCESS OF FERTILIZERS UNDER GREENHOUSE CONDITIONS 2 ABSTRACT The increase of the salinity in greenhouses of the Southeastern region of Brazilusually occur because of the overapplication of fertilizers in irrigation water; therefore, preventive and corrective actions are necessary. Manure overuse, lack of rains and continuous soil water evaporation can increase salt concentration in a soil solution. The aim of this work was evaluate the use viability of the Hoffman’s formula (1980) on calculation of leaching depthes necessary for recovery of salinized soil. The experiment was carried out in two greenhouses located in the experimental area of the Department of Rural Engineering of the Escola Superior de Agricultura “Luiz de Queiroz” - USP, in Piracicaba, State of São Paulo, Brazil. The study took advantage of a previous experiment, in which the experimental parcel soil was submitted to a process of artificial salinization by fertilizer addition. Twenty experimental parcels were used and had initial salinity of the 0-40 cmlayer, between 2 and 6 dS m-1, previously evaluated by the measurement electric conductivity of the saturation extract. The depth of leaching water was calculated for each salinity level, in order to lower the concentration salts in the soil solution for levels close to 1 dS m-1. The results showed that Hoffman’s formula underestimated the water depth and, thus, it was necessary to apply more water to completely recover the salinized soil. KEYWORDS: salinity, leaching, electric conductivity.
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Nachshon, U., A. Ireson, G. van der Kamp, S. R. Davies und H. S. Wheater. „Impacts of climate variability on wetland salinization in the North American prairies“. Hydrology and Earth System Sciences 18, Nr. 4 (01.04.2014): 1251–63. http://dx.doi.org/10.5194/hess-18-1251-2014.
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Abstract. The glaciated plains of the North American continent, also known as the "prairies", are a complex hydrological system characterized by hummocky terrain, where wetlands, containing seasonal or semi-permanent ponds, occupy the numerous topographic depressions. The prairie subsoil and many of its water bodies contain high salt concentrations, in particular sulfate salts, which are continuously cycled within the closed drainage basins. The period between 2000 and 2012 was characterized by an unusual degree of climatic variability, including severe floods and droughts, and this had a marked effect on the spatial distribution, water levels and chemical composition of wetland ponds. Understanding the geochemical and hydrological processes under changing environmental conditions is needed in order to better understand the risk and mitigate the impacts of future soil and water salinization. Here we explore salt dynamics in the prairies using field observations from St. Denis, Saskatchewan, taken mostly over the last 20 years. Measurements include meteorological data, soil moisture, soil salinity, groundwater levels and pond water volume, salinity, and chemical composition. The record includes periods of exceptional snow (1997, 2007) and periods of exception rainfall (2010, 2012), both of which resulted in unusually high pond water levels. Measurements indicated that severe pond salinization only occurred in response to extreme summer rainfall. It is hypothesized that since rainfall water infiltrates through the soil towards the depressions, while snowmelt water flows mainly as surface water over frozen soils, they have markedly different impacts on salt transport and pond salinization. Whilst this hypothesis is consistent with our conceptual understanding of the system, it needs to be tested further at a range of field sites in the prairies.
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Liang, Shu Yun, Ting Nien Wu, Yu Sheng Wu, Yen Chin Chou und Cheng Haw Lee. „Assessment of Aquifer Salinization Beneath an Offshore Industrial Park Based on Solute Transport Calculation“. Advanced Materials Research 779-780 (September 2013): 1285–88. http://dx.doi.org/10.4028/www.scientific.net/amr.779-780.1285.
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The purpose of this study is to assess aquifer salinization in the coastal area of an Offshore Industrial Park in Taiwan. Study area belongs to the new Delta Holocene alluvium, which is composed of clay, silt, sand, gravel and their mixture. Groundwater quality measurements including electrical conductivity, total dissolved solids, chloride and sulfate were used as indicator to evaluate aquifer salinization. Regional groundwater flows from the middle of study area to the embracing beach, which is the typical island-type-like distribution of groundwater lens. Temporal variations of chloride concentrations in monitoring wells were simulated based on the calculation of solute transport. The simulation result matched with the observation that rainfall leaching could cause dilution of chloride concentration and lessen aquifer salinization. Solute exchange at the interface of fresh water and saline water strongly affected desalinization rate in groundwater, and thus desalinization rate was dependent on its distance from the seashore. According to the calculation of solute transport, it might take about 14 years for complete desalinization through continual rainfall leaching.
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Nachshon, U., A. Ireson, G. van der Kamp, S. R. Davies und H. S. Wheater. „Impacts of climate variability on wetland salinization in the North American Prairies“. Hydrology and Earth System Sciences Discussions 10, Nr. 11 (08.11.2013): 13475–503. http://dx.doi.org/10.5194/hessd-10-13475-2013.
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Abstract. The glaciated plains of the North American continent, also known as the "prairies", are a complex hydrological system characterized by hummocky terrain, where wetlands, containing seasonal or semi-permanent ponds, occupy the numerous topographic depressions. The prairie subsoil and many of its water bodies contain high salt concentrations, in particular sulfate salts, which are continuously cycled within the closed drainage basins. The period between 2000 and 2012 was characterized by an unusual degree of climatic variability, including severe floods and droughts, and this had a marked effect on the spatial distribution, water levels and chemical composition of wetland ponds. Understanding the geochemical and hydrological processes under changing environmental conditions is needed in order to better understand the risk and mitigate the impacts of future soil and water salinization. Here we explore salt dynamics in the prairies using field observations from St. Denis, Saskatchewan, taken over the last 40 yr. Measurements include meteorological data, soil salinity, groundwater levels and pond water volume, salinity, and chemical composition. The record includes periods of exceptional snow (1997, 2007) and periods of exception rainfall (2010, 2012), both of which resulted in unusually high pond water levels. However, severe salinization only occurred in response to extreme summer rainfall. We hypothesize that since rainfall and snowmelt activate different hydrological pathways, they have markedly different impacts on salinization. We propose that a wet condition associated with high snowmelt conditions does not pose a strong threat to salinization, which has important implications for agricultural planning. Whilst this hypothesis is consistent with our conceptual understanding of the system, it needs to be tested further at a range of field sites in the prairies.
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Le, Thanh N., Duy X. Tran, Thuong V. Tran, Sangay Gyeltshen, Tan V. Lam, Tung H. Luu, Dung Q. Nguyen und Tuyet V. Dao. „Estimating Soil Water Susceptibility to Salinization in the Mekong River Delta Using a Modified DRASTIC Model“. Water 13, Nr. 12 (10.06.2021): 1636. http://dx.doi.org/10.3390/w13121636.
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Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.
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Shukalo, D. M., und T. Y. Shul’ga. „RESEARCH OF LONG-TERM SEASONAL VARIABILITY OF TEMPERATURE AND SALINITY IN THE SEA OF AZOV FOR THE PERIOD 1913–2018“. Ecology. Economy. Informatics.System analysis and mathematical modeling of ecological and economic systems 1, Nr. 5 (2020): 220–23. http://dx.doi.org/10.23885/2500-395x-2020-1-5-220-223.
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One of the most demanded directions of oceanographic problems is the study of long-term variability and modeling of future climatic changes and also the possibility of obtaining continuous information on the thermohaline structure of the sea based on the joint use of remote sensing data and the results of assimilation modeling. In current paper, research, of the Sea of Azov for the period 1913–2018 was carried out. We used the data of contact measurements from the oceanographic data base of the SSC RAS, Atlas of climate change in large marine ecosystems of the Northern Hemisphere, as well as data from the oceanographic data bank of the Marine Hydrophysical Institute RAS. Based on the analysis of the information, the calculation of the average monthly temperature and salinity was carried out, the periods of anomalous temperature were revealed, the periods of salinization and desalination of the Azov Sea also were noted. Data analysis made possibility to identify intrasecular climate fluctuations. Abnormally cold water temperature in winter was noted in the periods: 1926–1932, 1951– 1956, 2003–2012. In turn, the abnormally warm water temperature in winter, which was recorded in the periods: 1935–1939, 1958–1972, 1983–1992. by accompanied a cold spring-summer period. During the last five years the spring-summer period is characterized by an increased water temperature of the Azov Sea. The long-term variability of the salinity of the Sea of Azov significantly depends on the inflow of saltier waters of the Black Sea and river runoff. Due to these circumstances, the Sea of Azov is characterized by periods of salinization and desalination: the period of salinization was recorded from 1955 to 1973, a shorter period of desalination falls on 2003–2018. On average, the value of the ratio between the mean monthly salinity values during these periods is 2,2 times.
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Rivera Garcia, Arzu, Géza Tuba, Györgyi Kovács, Lúcia Sinka und József Zsembeli. „Methodology adaptation and development to assess salt content dynamics and salt balance of soils under secondary salinization“. Acta Agraria Debreceniensis, Nr. 1 (01.06.2021): 199–206. http://dx.doi.org/10.34101/actaagrar/1/8326.
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The effect of irrigation with saline water (above 500 mg L-1) is considered a problem of small-scale farmers growing vegetable crops with high water demand in the hobby gardens characteristic of the Hungarian Great Plain. In order to simulate the circumstances of such hobby garden, we set up an experiment including five simple drainage lysimeters irrigated with saline water in the Research Institute of Karcag IAREF UD in 2019. We regularly measured the electric conductivity (EC) of the soil referring to its salt content and the soil moisture content with mobile sensors. Before and after the irrigation season, soil samples from the upper soil layer (0-0.6 m) were taken for laboratory analysis and the soil salt balance (SB) was calculated. The actual salt balance (SBact) was calculated of the upper soil layer (0-0.6 m) based on the salt content of the obtained soil samples. The theoretical salt balance (SBth) was calculated by the total soluble salt content of the irrigation water and leachates. During the irrigation season, we experienced fluctuating EC in the topsoil in close correlation with the soil moisture content. Based on the performed in-situ EC measurements, salts were leached from the upper soil layer resulting in a negative SB. Combining SBact and SBth of the soil columns of the lysimeters, we estimated the SB of the deeper (0.6-1.0 m) soil layer. We quantified 12% increase of the initial salt mass due to accumulation. We consider this methodology to be suitable for deeper understanding secondary salinization, which can contribute to mitigating its harmful effect. By repeating our measurements, we expect similar results proving that saline irrigation waters gained from the aquifers through drilled wells in Karcag are potentially suitable for irrigation if proper irrigation and soil management are applied.
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de Louw, P. G. B., Y. van der Velde und S. E. A. T. M. van der Zee. „Quantifying water and salt fluxes in a lowland polder catchment dominated by boil seepage: a probabilistic end-member mixing approach“. Hydrology and Earth System Sciences 15, Nr. 7 (07.07.2011): 2101–17. http://dx.doi.org/10.5194/hess-15-2101-2011.
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Abstract. Upward saline groundwater seepage is leading to surface water salinization of deep lying polders in the Netherlands. Identifying measures to reduce the salt content requires a thorough understanding and quantification of the dominant sources of water and salt on a daily basis. However, as in most balance studies, there are large uncertainties in the contribution from groundwater seepage. Taking these into account, we applied a probabilistic (GLUE) end-member mixing approach to simulate two years of daily to weekly observations of discharge, salt loads and salt concentration of water pumped out of an artificially drained polder catchment area. We were then able to assess the contribution from the different sources to the water and salt balance of the polder and uncertainties in their quantification. Our modelling approach demonstrates the need to distinguish preferential from diffuse seepage. Preferential seepage via boils contributes, on average, 66 % to the total salt load and only about 15 % to the total water flux into the polder and therefore forms the main salinization pathway. With the model we were able to calculate the effect of future changes on surface water salinity and to assess the uncertainty in our predictions. Furthermore, we analyzed the parameter sensitivity and uncertainty to determine for which parameter the quality of field measurements should be improved to reduce model input and output uncertainty. High frequency measurements of polder water discharge and weighted concentration at the outlet of the catchment area appear to be essential for obtaining reliable simulations of water and salt fluxes and for allotting these to the different sources.
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de Louw, P. G. B., Y. van der Velde und S. E. A. T. M. van der Zee. „Quantifying water and salt fluxes in a lowland polder catchment dominated by boil seepage: a probabilistic end-member mixing approach“. Hydrology and Earth System Sciences Discussions 8, Nr. 1 (11.01.2011): 151–88. http://dx.doi.org/10.5194/hessd-8-151-2011.
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Abstract. Upward saline groundwater seepage is leading to surface water salinization of low-lying polders in the Netherlands. Identifying measures to reduce the salt content requires a thorough understanding and quantification of the dominant sources water and salt on a daily basis. However, as in most balance studies, there are large uncertainties about the contribution of groundwater seepage. Taking these into account, we applied a probabilistic (GLUE) end-member mixing approach to simulate two years of daily to weekly observations of discharge, salt loads and salt concentrations of water pumped out of an artificially drained polder catchment area. We were then able to assess the contribution of the different sources to the water and salt balance of the polder and the uncertainties in their quantification. Our modelling approach demonstrates the need to distinguish preferential from diffuse seepage. Preferential seepage via boils contributes, on average, 66% to the total salt load and only about 15% to the total water flux into the polder and therefore forms the main salinization pathway. With the model we were able to calculate the effect of future changes on surface water salinity and to assess the uncertainty in our predictions. Furthermore, we analyzed the parameters sensitivity and uncertainty to determine for which parameter the quality of field measurements should be improved to the reduce model input and output uncertainty. High frequency measurements of polder water discharge and weighted concentration at the outlet of the catchment area appear to be essential for obtaining reliable simulations of water and salt fluxes and for allotting these to the different sources.
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Borfecchia, Flavio, Paola Crinò, Angelo Correnti, Anna Farneti, Luigi De Cecco, Domenica Masci, Luciano Blasi, Domenico Iantosca, Vito Pignatelli und Carla Micheli. „Assessing the Impact of Water Salinization Stress on Biomass Yield of Cardoon Bio-Energetic Crops through Remote Sensing Techniques“. Resources 9, Nr. 10 (20.10.2020): 124. http://dx.doi.org/10.3390/resources9100124.
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Various species of cultivated thistle, such as Cynara cardunculus L. (cardoon), exhibit interesting features for industrial biomass production as bioenergy crops, given also their advantageous adaptation capacities to typical Mediterranean climate trends, with noticeable resilience to drought and salinization stresses. The in situ hyperspectral reflectance responses of three genotypes of cardoon plants, irrigated with water at different salinity levels, have been tested for assessing the effects on their biophysical parameters, aiming at improving the biomass yield for bioenergy production, minimizing at same time the environmental impacts and the exploitation of soils and waters resources. The leaf and canopy reflectance hyperspectral signatures, acquired at three different growth stages with biometric measurements, were statistically analyzed (ANOVA, Tukey’s test, graphs), as noise-resilient spectral indices, sensible to different plant features of interest. Their broadband versions, based on the Landsat 8 OLI and Sentinel 2 MSI satellite sensors, were also evaluated in perspective of operative and extensive remote crop monitoring from space. The results highlighted significant differences in some spectral index responses, related to different cardoon genotypes and water salt concentration. The biometric data supported by red-edge indices modelling evidenced the impact of the highest salt water concentration (200 mM/L) on the plant growth and yield.
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Shaddad, Sameh M., Gabriele Buttafuoco und Annamaria Castrignanò. „Assessment and Mapping of Soil Salinization Risk in an Egyptian Field Using a Probabilistic Approach“. Agronomy 10, Nr. 1 (07.01.2020): 85. http://dx.doi.org/10.3390/agronomy10010085.
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The assessment of soil salinization risk at the field scale requires modeling of the spatial variability of soil salinity. This paper presents a probabilistic approach to estimate and map a risk index using all available auxiliary information. A probabilistic methodology is proposed to estimate the conditional probability of exceeding the assigned threshold value of a generic indicator of soil salinity. A geostatistical non-parametric technique, probability kriging, was used to assess the risk of soil salinization and delineate different hazard zones within a field. The technique relies on indicator coding of information. The approach was applied to soil electrical conductivity measurements collected in an experimental field located in the Nile Delta region in Egypt, and submitted over time to trials with different fertilization treatments. The application of the method allowed delineation of a north-eastern zone in the field with a high risk of soil salinization due to its lack of cultivation for a long time and nearness to buildings that prevent water infiltration. The method proved to be quite promising from the perspective of precision agriculture and it is easily extendable to any sort of remote and proximal sensing auxiliary information, including information on the deepest layers of soil.
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Mertzanides, Y., N. Economou, H. Hamdan und A. Vafidis. „IMAGING SEAWATER INTRUSION IN COASTAL ZONE OF KAVALA (N. GREECE) WITH ELECTRICAL RESISTIVITY TOMOGRAPHY“. Bulletin of the Geological Society of Greece 43, Nr. 4 (25.01.2017): 1802. http://dx.doi.org/10.12681/bgsg.11366.
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The needs for water supply in the western coastal zone of Kavala (N. Greece) have been rapidly increased during the last decades because of the high tourist and agricultural development. This resulted to a number of wells that drilled along the coastline. During summer period, when human and irrigation consumptions are maximized, phenomena of groundwater salinization are observed. Although restrictions to new drillings have been taken, salinization in some aquatic systems of the area tends to become a major environmental and economical issue. The only available information till now was a timeseries of groundwater electrical conductivity measurements, in some of the wells of the area. This information is useful but not adequate for the study of the salt intrusion mechanism. Geophysical investigation was carried out and electrical resistivity tomography (ERT) was chosen as the most appropriate technique for the case. The geophysical survey was set in a site between the coastline and an existing borehole. The 2D ERT profiles gave a clear image of geoelectrical heterogeneities, associated with seawater intrusion in the coastal aquifers, contributing to future measures towards a rational management of ground water resources in the area.
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America, Ilja, Perry de Louw, George Bier und Sjoerd van der Zee. „Influence of tides, bathymetry, lithology and regional flows on the salinization process in nature area the Rammegors“. E3S Web of Conferences 54 (2018): 00001. http://dx.doi.org/10.1051/e3sconf/20185400001.
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Nature area Rammegors, which has recently been transformed from a fresh inner-dyke nature area to a salt tidal area. Due to this transformation, salt water is infiltrating in a fresh waterlens. This salinisation process is investigated in more detail by two- and three dimensional models together with mearsurements in the area. Zeeland project FRESHEM has provided detailed isohaline maps of the area and Deltares is making transient isohaline maps based on measurements made by an ERT-cable which is situated in Rammegors. These data has been and will be used to investigate which factors; bathymetry, lithology, tides or regional groundwater flow, will have the largest impact on the salinization process in Rammegors. This investigation shows that discretization size has an influence on the speed and spatial distribution of salt plumes. Lithology has the largest influence on the salinization process, followed by bathymetry. Spring and neap tides do differ from the normal tides situation only when bathymetry is not taken into account.
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Braaten, Robert O., und Mark Flaherty. „Salt balances of inland shrimp ponds in Thailand: implications for land and water salinization“. Environmental Conservation 28, Nr. 4 (Dezember 2001): 357–67. http://dx.doi.org/10.1017/s0376892901000388.
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Brackish water ponds for farming black tiger shrimp (Penaeus monodon) have recently proliferated in inland areas of Thailand's central plain, raising concerns about land and water salinization. The environmental impacts of inland shrimp farming were assessed by analysing the salt balance for an inland shrimp farm. Field data on water fluxes and pond salinity, collected from nine ponds in Chachoengsao Province from May–July 1999, were used to model the salt balance for a typical shrimp pond over one growout cycle. During growout, seepage represented 38% (11.5 tonnes crop−1) of salt losses, pond discharge 33% (9.7 tonnes crop−1), and accumulation of salt in pond sediment 6% (1.8 tonnes crop−1). About 23% of the initial salt content remained at harvest and could have been recycled. However, the majority (84% on average) was discharged to the irrigation canals. Much of the salt in pond sediment was also exported to the canal system through tidal flushing of the ponds. Field measurements of salinity were taken in adjacent canals and rice paddies to explore the impacts of salt exports from shrimp ponds. Pond discharge caused increases in canal salinity above levels that would impact on yields of irrigated rice and orchard crops, the main land uses in the region. Elevated soil and water salinity in adjacent rice fields was probably related to lateral seepage from the ponds. The salt budget was also modelled for a zero discharge farming system, promoted by proponents of inland shrimp farming as having few impacts. However, the results suggest that, even in zero discharge ponds, almost half of the initial pond salt content is exported through seepage (45%, 12.4 tonnes crop−1), with another 6% (1.8 tonnes crop−1) deposited in sediments. While techniques exist for mitigating much of the salt leakage, the likelihood of their uptake in Thailand is low. Further expansion of inland shrimp farming in the central plain is therefore likely to contribute substantial salt load to the area's land and water resources.
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Pliakas, F., A. Mouzaliotis, A. Kallioras und I. Diamantis. „HYDROGEOLOGICAL ASSESSMENT OF THE SALINIZATION PROBLEM OF XILAGANI - IMEROS AQUIFER SYSTEM IN SW PLAIN AREA OF RHODOPE PREFECTURE, GREECE“. Bulletin of the Geological Society of Greece 40, Nr. 2 (01.01.2007): 536. http://dx.doi.org/10.12681/bgsg.16319.
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This paper investigates the progress of groundwater salinization within the plain area ofXilagani - Imeros, in SW part ofRhodope Prefecture, as well as the suitability of groundwater for drinking and irrigation use, after qualitative classification of groundwater samples from selective wells of the study area based on relevant guidelines. Some managerial suggestions for the confrontation of the seawater intrusion regime of the study area are also included. The investigation in question took place between 1994-1997 and 2002-2006, and involved drilling of test wells, geoelectric sounding measurements, grain size analyses, elaboration of hydro logical data, monitoring and relevant analysis of the groundwater level fluctuations in selective wells, electrical conductivity measurements as well as conducting chemical analyses of water samples from selective wells of the study area and relevant elaboration.
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Sulzbacher, H., H. Wiederhold, B. Siemon, M. Grinat, J. Igel, T. Burschil, T. Günther und K. Hinsby. „Numerical modelling of climate change impacts on freshwater lenses on the North Sea Island of Borkum“. Hydrology and Earth System Sciences Discussions 9, Nr. 3 (15.03.2012): 3473–525. http://dx.doi.org/10.5194/hessd-9-3473-2012.
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Abstract. A numerical variable-density groundwater model is set up for the North Sea Island of Borkum to estimate climate change impacts on coastal aquifers and especially the situation of barrier islands in the Wadden Sea. The database includes information from boreholes, a seismic survey, a helicopter-borne electromagnetic survey (HEM), monitoring of the freshwater-saltwater boundary by vertical electrode chains in two boreholes, measurements of groundwater table, pumping and slug tests, as well as water samples. Based on a statistical analysis of borehole columns, seismic sections and HEM, a hydrogeological model is set up. The groundwater model is developed using the finite-element programme FEFLOW. The variable-density groundwater model is calibrated on the basis of hydraulic, hydrological and geophysical data, in particular spatial HEM and local monitoring data. Verification runs with the calibrated model show good agreement between measured and computed hydraulic heads. A good agreement is also obtained between measured and computed density or total dissolved solids data for both the entire freshwater lens on a large scale and in the area of the well fields on a small scale. For simulating future changes in this coastal groundwater system until the end of the current century we use the climate scenario A2, specified by the Intergovernmental Panel on Climate Change and in particular the data for the German North Sea coast. Simulation runs show proceeding salinization with time beneath the well fields of the two waterworks Waterdelle and Ostland. The modelling study shows that spreading of well fields is an appropriate protection measure against excessive salinization of the water supply until the end of the current century.
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Coraspe-Amaral, Marcos Vinícius, Marcelo Mattos Pedreira, Guilherme de Souza Moura, Deliane Cristina Costa, Alcione Eneida dos Santos und Eglerson Duarte. „Combination of diet and water salinity in larviculture of piabanha-do-Pardo ( Brycon vonoi , Lima 2017)“. Revista Ceres 64, Nr. 4 (August 2017): 384–91. http://dx.doi.org/10.1590/0034-737x201764040007.
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ABSTRACT Two experiments were carried out to study piabanha-do-Pardo (Brycon vonoi) larvae development. In the first, six different diets were evaluated, being Artemia sp., plankton, feeds, feeds + Artemia sp., feeds + plankton, and Prochilodus hartii (curimba) larvae. In the second, four different water salinity levels (0, 2, 4, and 6‰) were tested. Both assays were entirely randomized design experiments, lasting for 10 days. At the end of these trials, fish biomass, survival, total length, weight, and specific growth rate were measured. Additionally, water quality, temperature, oxygen, pH, and electric conductivity measurements were made every three days. The curimba larvae diet presented higher survival rate (47.2%) and biomass weight (2.5 g) than the other diets, which were similar among each other. Piabanha-do-Pardo larvae weight, length, and specific growth rate varied with the offered diets. All water salinity treatments showed better results than those observed for fresh water. When cultivated in 2‰ salinization, larvae had 52.5% survival rates and 0.49 g biomass weight, while in the fresh water these results were 6.6% and 0.23 g, respectively. To conclude, we may identify curimba larvae as an adequate diet, and a 2‰ water salinity as recommended if Artemia sp. larvae are fed to piabanha-do-Pardo larvae.
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Greggio, Nicolas, Beatrice M. S. Giambastiani, Pauline Mollema, Mario Laghi, Donato Capo, Giovanni Gabbianelli, Marco Antonellini und Enrico Dinelli. „Assessment of the Main Geochemical Processes Affecting Surface Water and Groundwater in a Low-Lying Coastal Area: Implications for Water Management“. Water 12, Nr. 6 (16.06.2020): 1720. http://dx.doi.org/10.3390/w12061720.
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Hydrogeochemical analyses were carried out to identify geochemical processes occurring in the low-lying coastal aquifer of Ravenna, North Adriatic Sea (Italy). The area is characterized by a complex coexistence of several environments: coastal dunes, paleodunes, pine forests, freshwater wetlands, rivers, brackish lagoons, gravel pit lakes, reclaimed lands, agricultural fields and industrial areas. Water quality is of primary importance for the sustainability of these, areas and a full understanding of geochemical processing is fundamental for their management. A total of 104 water samples was collected from groundwater wells and surface water bodies, and analyzed for the major and trace elements (TEs). Field measurements of chemical-physical parameters were carried out by a multiparameter device XS PCD650; major elements were analyzed following the Italian National Environmental Agency standards (APAT-IRSA 2003), while TEs were analyzed by ICP-AES/ICP-MS. The major findings include: organic matter degradation in salinized and anoxic conditions; TEs concentrations related to water–sediment interactions, i.e., adsorption, ion exchange, redox reactions, mineral dissolution and precipitation; anthropogenic contamination from pesticides and fertilizers use; pollution from industrial district; TEs enrichments and depletion due to groundwater salinization and water management practices; comparison of TEs concentrations with respect to national and international thresholds. The findings can provide water managers and local authorities with a comprehensive framework of the coastal water hydrochemistry, allowing a better understanding of the effects of current management practices and the design of mitigation measures to reduce water resource deterioration in the studied coastal area.
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Noori, Roohollah, Mohsen Maghrebi, Ali Mirchi, Qiuhong Tang, Rabin Bhattarai, Mojtaba Sadegh, Mojtaba Noury, Ali Torabi Haghighi, Bjørn Kløve und Kaveh Madani. „Anthropogenic depletion of Iran’s aquifers“. Proceedings of the National Academy of Sciences 118, Nr. 25 (14.06.2021): e2024221118. http://dx.doi.org/10.1073/pnas.2024221118.
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Global groundwater assessments rank Iran among countries with the highest groundwater depletion rate using coarse spatial scales that hinder detection of regional imbalances between renewable groundwater supply and human withdrawals. Herein, we use in situ data from 12,230 piezometers, 14,856 observation wells, and groundwater extraction points to provide ground-based evidence about Iran’s widespread groundwater depletion and salinity problems. While the number of groundwater extraction points increased by 84.9% from 546,000 in 2002 to over a million in 2015, the annual groundwater withdrawal decreased by 18% (from 74.6 to 61.3 km3/y) primarily due to physical limits to fresh groundwater resources (i.e., depletion and/or salinization). On average, withdrawing 5.4 km3/y of nonrenewable water caused groundwater tables to decline 10 to 100 cm/y in different regions, averaging 49 cm/y across the country. This caused elevated annual average electrical conductivity (EC) of groundwater in vast arid/semiarid areas of central and eastern Iran (16 out of 30 subbasins), indicating “very high salinity hazard” for irrigation water. The annual average EC values were generally lower in the wetter northern and western regions, where groundwater EC improvements were detected in rare cases. Our results based on high-resolution groundwater measurements reveal alarming water security threats associated with declining fresh groundwater quantity and quality due to many years of unsustainable use. Our analysis offers insights into the environmental implications and limitations of water-intensive development plans that other water-scarce countries might adopt.
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Kasim, Nijat, Balati Maihemuti, Rukeya Sawut, Abdugheni Abliz, Cui Dong und Munira Abdumutallip. „Quantitative Estimation of Soil Salinization in an Arid Region of the Keriya Oasis Based on Multidimensional Modeling“. Water 12, Nr. 3 (20.03.2020): 880. http://dx.doi.org/10.3390/w12030880.
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Soil salinity is one of the major factors causing land degradation and desertification on earth, especially its important damage to farming activities and land-use management in arid and semiarid regions. The salt-affected land is predominant in the Keriya River area of Northwestern China. Then, there is an urgent need for rapid, accurate, and economical monitoring in the salt-affected land. In this study, we used the electrical conductivity (EC) of 353 ground-truth measurements and predictive capability parameters of WorldView-2 (WV-2), such as satellite band reflectance and newly optimum spectral indices (OSI) based on two dimensional and three-dimensional data. The features of spectral bands were extracted and tested, and different new OSI and soil salinity indices using reflectance of wavebands were built, in which spectral data was pre-processed (based on First Derivative (R-FD), Second Derivative (R-SD), Square data (R-SQ), Reciprocal inverse (1/R), and Reciprocal First Derivative (1/R-FD)), utilizing the partial least-squares regression (PLSR) method to construct estimation models and mapping the regional soil-affected land. The results of this study are the following: (a) the new OSI had a higher relevance to EC than one-dimensional data, and (b) the cross-validation of established PLSR models indicated that the β-PLSR model based on the optimal three-band index with different process algorithm performed the best result with R2V = 0.79, Root Mean Square Errors (RMSEV) = 1.51 dS·m−1, and Relative Percent Deviation (RPD) = 2.01 and was used to map the soil salinity over the study site. The results of the study will be helpful for the study of salt-affected land monitoring and evaluation in similar environmental conditions.
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Almeida, Ghislaine M. de, und Gerson Cardoso da Silva Junior. „Fatores hidrogeológicos no estudo da intrusão salina em aqüíferos costeiros da região litorânea do município de Maricá - RJ“. Anuário do Instituto de Geociências 30, Nr. 2 (01.12.2007): 104–17. http://dx.doi.org/10.11137/2007_2_104-117.
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The oceanic area of Maricá, in the east coast of the Rio de Janeiro State, relies on groundwater as its main source of fresh water supply along with the use of water tank trucks. With the increasing demand of water resources, water supply and contamination problems are foreseen, and sea water intrusion phenomenon is also expected in these aquifers. The groundwater resource of the target area has been submitted to quality degradation due to the advance of the saline wedge, the excess of pumping without control and also the pollution of organic origin. Considering this situation, the study aims to contribute to a better knowledge of the hydrogeological characteristics in order to assist the aquifer management of the coastal area under study. The area comprises a granular aquifer and local geology consists basically of marine and fluvio-marine Quaternary sandbar deposits, overlying a crystalline basement of variable depth. The study included the evaluation of previously existing hydrological data in the area, rainfall data, and a field survey in 41 wells, with measurements of hydrodynamic and physical-chemical parameters (temperature, electric conductivity, hydraulic head). Furthermore, an automatic instrumentation was installed to evaluate the response of the aquifer to recharge. Results indicate that aquifer salinity levels tend to rise in the SE portion, and also, apparently, there has been an increase in aquifer salinization in recent years, demanding urgent management actions. The automatic instrumentation shows that Maricá coastal aquifer gives a rapid response to seasonal factors and climate, showing some vulnerability, but also rapid recharge and dilution capacity.
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Sang, Shilei, Heng Dai, Bill X. Hu, Yanru Hao, Tong Zhou und Jin Zhang. „The Study of Hydrogeochemical Environments and Microbial Communities along a Groundwater Salinity Gradient in the Pearl River Delta, China“. Water 11, Nr. 4 (18.04.2019): 804. http://dx.doi.org/10.3390/w11040804.
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The salinization of groundwater is an issue in coastal areas because it causes the deterioration of freshwater resources, significantly impacting human livelihoods and ecosystems. This study integrated isotopic geochemical measurements with high-throughput sequencing of 16S rRNA gene amplicons to evaluate the source of groundwater salinity and the influence of hydrogeochemical variations on microbial communities under different salinity gradients in the Pearl River Delta of China. Results showed that the groundwater salinity in this area varied from fresh water in the inland area to brackish water, and then to saline water close to the southeast shoreline. The major ions (Na+, K+, Ca2+, Mg2+, Cl−, NO3−, SO42−, and HCO3−) and isotope analyses (2H, 3H, 18O, and 14C) indicated that the groundwater in the confined aquifer was recharged by local precipitation and seawater. A further 14C analysis showed that the salinity of the groundwater was likely attributed to the Holocene transgression. Analysis of the microbial community showed that γ-proteobacteria were frequently observed in all the groundwater samples, while the other main microbial community at class level varied greatly, from β-proteobacteria in the freshwater wells to ε-proteobacteria in the brackish wells and to Bacilli in the saline wells. Exiguobacterium and Acinetobacter were dominant in saline water and the brackish water sample of Q144, while Sulfuricurvum dominated in the brackish water sample of Q143. Aeromonas, no rank Gallionellaceae, no rank Methylophilaceae, Acidovorax, and Comamonas unevenly thrived in the freshwater samples collected from different locations. Therefore, the distribution of microbial communities reflected the salinity and hydrogeochemical characteristics of a groundwater aquifer, and can be regarded as a potential environmental indicator in the groundwater.
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Muzzillo, Rosalba, Livia Emanuela Zuffianò, Enzo Rizzo, Filomena Canora, Luigi Capozzoli, Valeria Giampaolo, Giorgio De Giorgio, Francesco Sdao und Maurizio Polemio. „Seawater Intrusion Proneness and Geophysical Investigations in the Metaponto Coastal Plain (Basilicata, Italy)“. Water 13, Nr. 1 (29.12.2020): 53. http://dx.doi.org/10.3390/w13010053.
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The Metaponto coastal plain extends about 40 km along the Ionian coast, between the Sinni and Bradano Rivers (southern Italy). During the 20th century, the increases in modern irrigation systems, land reclamation works, the overexploitation of wells, and agricultural and industrial activities have deeply modified land use and groundwater availability and quality along the plain. These modifications negatively impacted the natural systems in terms of groundwater and soil salinization, magnifying the risks due to seawater intrusion. In this study, we explored the proneness to seawater intrusion, testing a multidisciplinary approach based on hydrochemical and geophysical investigations. A significant portion of the coastal plain was selected for this purpose. A set of 49 groundwater samples was analyzed to define the chemical characteristics of the water and geoelectrical measurements were recorded along three long profiles. The geoelectrical surveys showed in detail the aquifer bottom pattern where it is deeply incised by paleovalleys, defining the main hydrostratigraphic features, as it is necessary to prevent seawater intrusion worsening. The hydrochemical data highlighted areas with higher seawater intrusion proneness. The acquired measurements show the high proneness to seawater intrusion, especially where the aquifer bottom is very deep below the sea level, also far from the coast, and the relevance of the detailed knowledge of the aquifer bottom in supporting any kind of management.
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Vrouhakis, Ioannis, Evangelos Tziritis, Andreas Panagopoulos und Georgios Stamatis. „Hydrogeochemical and Hydrodynamic Assessment of Tirnavos Basin, Central Greece“. Water 13, Nr. 6 (11.03.2021): 759. http://dx.doi.org/10.3390/w13060759.
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A combined hydrogeochemical and hydrodynamic characterization for the assessment of key aspects related to groundwater resources management was performed in a highly productive agricultural basin of the Thessaly region in central Greece. A complementary suite of tools and methods—including graphical processing, hydrogeochemical modeling, multivariate statistics and environmental isotopes—have been applied to a comprehensive dataset of physicochemical analyses and water level measurements. Results revealed that the initial hydrogeochemistry of groundwater was progressively impacted by secondary phenomena (e.g., ion exchange and redox reactions) which were clearly delineated into distinct zones according to data processing. The progressive evolution of groundwater was further verified by the variation of the saturation indices of critical minerals. In addition, the combined use of water level measurements delineated the major pathways of groundwater flow. Interestingly, the additional joint assessment of environmental isotopes revealed a new pathway from E–NE (which had never before been validated), thus highlighting the importance of the joint tools/methods application in complex scientific tasks. The application of multivariate statistics identified the dominant processes that control hydrogeochemistry and fit well with identified hydrodynamic mechanisms. These included (as dominant factor) the salinization impact due to the combined use of irrigation water return and evaporitic mineral leaching, as well as the impact of the geogenic calcareous substrate (mainly karstic calcareous formations and dolostones). Secondary factors, acting as processes (e.g., redox and ion exchange), were identified and found to be in line with initial assessment, thus validating the overall characterization. Finally, the outcomes may prove to be valuable in the progression toward sustainable groundwater resources management. The results have provided spatial and temporal information for significant parameters, sources, and processes—which, as a methodological approach, could be adopted in similar cases of other catchments.
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Elfjiji, H., A. Boukdir und A. Zitouni. „Application of the Electrical (Geophysical) Method for the Identification of the Sealed Bevel in the Coastal Region of Walidia Province of el Jadida – Morocco“. E3S Web of Conferences 37 (2018): 05003. http://dx.doi.org/10.1051/e3sconf/20183705003.
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The Walidia area knows a great development of agricultural, industrial, maritime activities and a very great demographic expansion. This development is accompanied by a growing demand for water. On the other hand, any intense abstraction of fresh water at a coastal aquifer capture field causes a decrease in groundwater flow and a lowering of the piezometric surface. There is therefore a danger of advancing towards the land of the saltwater bevel and salinization of groundwater which is gradually loaded into mineral salts and can reach abnormally high levels. This work deals with the application of geophysics by electrical sounding method to the in-depth study of the freshwater-salt water interface (salted bevel) on the one hand and the study of the lateral and vertical evolution of the geometry of the different aquifers. The principle of the method is, when performing an electrical survey, to research how varies, at a given point on the surface, the resistivity of the subsoil vertically. For this one executes in a same place a succession of measurements, increasing each time the dimensions of the device and thus the depth of investigation which is proportional to them. At this site, we explore a slice of ground increasingly thick and thus highlights the changes in geological constitution along the vertical. The electrical soundings were carried out with the classic Schlumberger device. The interpretation and the exploitation of the data of the electric soundings carried out made it possible to : Follow the evolution of the salted bevel roof, Draw the upstream limit (marine invasion) of salted bevel Hauterivian, on the one hand, and Valanginian and Jurassic on the other hand, Follow the roof structure of Dridrat limestone (Hauterivien) and limestones of Valanginien and Upper Jurassic, Draw the map of the marl roof of Safi (Hauterivian) constituting the impermeable substratum of Dridrat limestones.
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Palacios, Andrea, Juan José Ledo, Niklas Linde, Linda Luquot, Fabian Bellmunt, Albert Folch, Alex Marcuello et al. „Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer“. Hydrology and Earth System Sciences 24, Nr. 4 (30.04.2020): 2121–39. http://dx.doi.org/10.5194/hess-24-2121-2020.
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Abstract. Surface electrical resistivity tomography (ERT) is a widely used tool to study seawater intrusion (SWI). It is noninvasive and offers a high spatial coverage at a low cost, but its imaging capabilities are strongly affected by decreasing resolution with depth. We conjecture that the use of CHERT (cross-hole ERT) can partly overcome these resolution limitations since the electrodes are placed at depth, which implies that the model resolution does not decrease at the depths of interest. The objective of this study is to test the CHERT for imaging the SWI and monitoring its dynamics at the Argentona site, a well-instrumented field site of a coastal alluvial aquifer located 40 km NE of Barcelona. To do so, we installed permanent electrodes around boreholes attached to the PVC pipes to perform time-lapse monitoring of the SWI on a transect perpendicular to the coastline. After 2 years of monitoring, we observe variability of SWI at different timescales: (1) natural seasonal variations and aquifer salinization that we attribute to long-term drought and (2) short-term fluctuations due to sea storms or flooding in the nearby stream during heavy rain events. The spatial imaging of bulk electrical conductivity allows us to explain non-monotonic salinity profiles in open boreholes (step-wise profiles really reflect the presence of freshwater at depth). By comparing CHERT results with traditional in situ measurements such as electrical conductivity of water samples and bulk electrical conductivity from induction logs, we conclude that CHERT is a reliable and cost-effective imaging tool for monitoring SWI dynamics.
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Buselli, G., und D. R. Williamson. „Modeling of broadband airborne electromagnetic responses from saline environments“. GEOPHYSICS 61, Nr. 6 (November 1996): 1624–32. http://dx.doi.org/10.1190/1.1444081.
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The removal of vegetation for the development of nonirrigated agriculture and the associated increase in groundwater recharge and discharge has caused significant areas of salinization of surface soil and water resources in Australia. At least three types of salt profiles are known to indicate the relative magnitude of recharge. These profiles may be differentiated by their resistivity structure. Since a broadband airborne electromagnetic (AEM) method offers the possibility of readily obtaining resistivity soundings, modeling was carried out to investigate the ability of a broadband AEM system to distinguish different salt profile types. Salt profile types may be represented by a four‐layer resistivity model. The use of a broadband AEM system to distinguish the relative magnitude of the resistivity of a layer of high salt accumulation and the underlying layer forms the basis for efficiently identifying areas of high or low recharge. Where the resistivity of the underlying layer is greater than that of the salt accumulation, high recharge is indicated, and a lower resistivity of this layer implies low recharge. The response of each of the salt profile models was calculated in the frequency domain and then inverted back to a layered model. With noise added to the calculated responses, the inversion results show that the depth, thickness, and resistivity of a layer of high salt accumulation can be resolved by AEM measurements. Furthermore, the resistivity of this layer can be distinguished from the resistivity of the underlying layer. A high‐recharge profile may therefore be differentiated from a low‐recharge profile with AEM measurements. Since the quadrature component of the AEM response is relatively unaffected by noise caused by the primary field, the effect of using solely the quadrature component of the response was examined briefly as a second part of the AEM modeling investigation. It is found that simultaneous inversion of the quadrature part of the spatial components measured along the line of flight and in a vertical direction gives results similar to those when both the in‐phase and quadrature parts of these components are used in the inversion.
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Ma, Jun, Zhifang Zhou, Qiaona Guo, Shumei Zhu, Yunfeng Dai und Qi Shen. „Spatial Characterization of Seawater Intrusion in a Coastal Aquifer of Northeast Liaodong Bay, China“. Sustainability 11, Nr. 24 (09.12.2019): 7013. http://dx.doi.org/10.3390/su11247013.
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The safety of groundwater resources in coastal areas is related to the sustainable development of the national economy and society. Seawater intrusion is a serious problem threatening the groundwater environment in coastal areas. Climate change, tidal effects and groundwater exploitation may destroy the balance between salt water and fresh water in coastal aquifers, leading to seawater intrusion. The threat of seawater intrusion has attracted close attention, especially in the coastal areas of northern China, and the accuracy and efficiency of seawater intrusion monitoring need to be improved. The aim of this study was to fill the blanks in seawater intrusion research in the coastal aquifer of the Daqing River Catchment, northeastern Liaodong Bay, China, and determine the extent and evolutionary characteristics of seawater intrusion in this area. In this study, historical chloride concentration data were used to trace the evolution of the salinization, and electrical resistivity tomography (ERT) was used to supplement the data in areas with limited hydrochemical data and to detect the saltwater/freshwater interface, especially in the area near the Xihai Sluice. The results show that seawater intrusion in the Daqing River Catchment is mainly caused by overexploitation of groundwater. Since 2012, strict controls have been placed on the groundwater exploitation rate, and the chloride concentration of 250 mg/L has receded year by year, with saltwater being significantly reduced by 2018. The Daqing River plays an important role in the saltwater distribution. The Xihai Sluice, located in the lower reaches of the Daqing River, intercepts and controls the seawater intrusion in a certain range by raising the level of fresh groundwater to intercept and control saltwater intrusion within a certain range. The research results also confirmed that a combination of geophysical and geochemical methods is of great value in studying seawater intrusion, especially in areas with limited available hydrochemical data. A monitoring network with ERT instruments and wells should be established to collect regular measurements of the electrical resistivity distribution, as well as the groundwater level and chemical composition.
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Mazón Suástegui, José Manuel, Carlos Michel Ojeda Silvera, Milagro Ramona García Bernal, Daulemys Batista Sánchez und Fernando Abasolo Pacheco. „La Homeopatía incrementa la tolerancia al estrés por NaCl en plantas de frijol común (Phaseolus vulgaris L.) variedad Quivicán“. REVISTA TERRA LATINOAMERICANA 38, Nr. 1 (23.02.2020): 37. http://dx.doi.org/10.28940/terra.v38i1.584.
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Currently, the international scientif ic community is increasingly promoting the use of alternatives eco-friendly to the environment to solve agricultural problems, such as soil salinization. The use of agricultural homeopathy, as one of these alternatives, has increased because of its safety and proven effectiveness. This study assessed the effect of attenuating salinity stress (NaCl) of the homeopathic medicine Natrum muriaticum (NaM) on photosynthetic rate (TF) and morphometric variables of the common bean plant (Phaseolus vulgaris L.) variety white testa Quivican in initial plant growth stage. A completely randomized experimental design was applied with bifactorial arrangement (2A × 4B) where A = salinity levels (0 and 75 mM) and B = homeopathic dynamizations (NaM-7CH, NaM-13CH, NaM-7+13CH and distilled water [AD] as homeopathic control) with f ive replicates per treatment. The TF measurements were done twice a week, and the morphometric variables were measured at the end of the experimental evaluation period (35 days). In general, the assessed morphometric variables were favored with the application of the homeopathic treatments NaM 7CH and NaM 7+13CH; the increase in root length (LR) and fresh leaf biomass (BFH) were greater even when the plants were in salinity stress conditions (75mM NaCl). The TF reached the highest value when the plants in saline medium were treated with NaM-7CH, and an increase greater than 50% in PR was observed with respect to the (AD) control treatment. These results demonstrated a great potential of agricultural homeopathy as a bio-safe and low-cost alternative to increase P. vulgaris L. tolerance to NaCl and achieve greater areas of this crop.
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Timms, W. A., R. R. Young und N. Huth. „Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia“. Hydrology and Earth System Sciences 16, Nr. 4 (11.04.2012): 1203–19. http://dx.doi.org/10.5194/hess-16-1203-2012.
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Abstract. The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr−1 rainfall, potential evapotranspiration >2000 mm yr−1) such as parts of Australia's Murray-Darling Basin (MDB). In this rare study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8–1.2 m depth under perennial vegetation and at 2.0–2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91–229 t ha−1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ≥ 10 m depth that was not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m−1 at 21 to 37 m depth (N = 5), whereas deeper groundwater was less saline (290 mS m−1) with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM) software package predicted deep drainage of 3.3–9.5 mm yr−1 (0.7–2.1% rainfall) based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent soil water content, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total), and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge appears to be negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditions after changes in land use and a thick clay dominated vadose zone. This is in contrast to regional groundwater modelling that assumes annual recharge of 0.5% of rainfall. Importantly, it was found that leaching from episodic deep drainage could not cause discharge of saline groundwater in the area, since the water table was several meters below the incised river bed.
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Cserni, Imre. „Analysis of Soil Hydraulic Conductivity in Palm Plantations in the Saline Soils of the Oued Rhir“. Agrokémia és Talajtan 51, Nr. 1-2 (01.03.2002): 47–52. http://dx.doi.org/10.1556/agrokem.51.2002.1-2.6.
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The aim of the study was to determine K-factors of homogeneous zones in palm-groves in order to make possible the interpolation of these values to other similar areas, and by this way to help the calculation of draining parameters. Another goal was to interpret the agronomical aspects of the results. Investigations for the determination of conductivity factors (K-factors) were carried out in the palm-groves of the Oued Rhir Valley. The measurements - conducted three times - were made by the auger-hole method. After boring the hole, a perforated cylinder was placed into it to prevent falling in. K-factor values were calculated after van Beers. The mean of the three calculations was given as the end result for the K-factors. Our results show that K-factor values are influenced by the porosity, type, bulk density and texture of soils, their salt content and the form of gypsum. The K-factor was extremely high in case of sandy soils and soils containing crystallized gypsum. Water conductivity was moderate in case gley and pseudogley were located in deeper layers. The lowest values occurred when gypsum was found in cemented coherent particles. Salinization in deeper layers influenced hydraulic conductivity only in case it was associated with finer texture and airless layers. Besides date production, the traditional growing of nitrogen-fixing perennial legumes (alfalfa, Egyptian clover, melilot, etc.) in palm-groves is essential. Systemic flooding irrigation decreases the salt content of soils, increases date and legumes yields. Legumes - by their root-system - improve the nitrogen balance, structure and water drainage of soils. The green parts of the cultivated legumes serve as fodder for animals (goats, sheep, cows), which turn it to manure. This manure increases the nutrient supply of the soils for palm-trees and vegetables. The positive results of stubble and root manuring (green manuring) of legumes is also confirmed by experiments on sandy soils. The elaboration of a good plant rotation is possible. At last, date and vegetables produced in this way could be sold better on the world market as bioproducts.
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Timms, W. A., R. R. Young und N. Huth. „Implications of deep drainage through saline clay for groundwater recharge and sustainable cropping in a semi-arid catchment, Australia“. Hydrology and Earth System Sciences Discussions 8, Nr. 6 (15.11.2011): 10053–93. http://dx.doi.org/10.5194/hessd-8-10053-2011.
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Abstract. The magnitude and timing of deep drainage and salt leaching through clay soils is a critical issue for dryland agriculture in semi-arid regions (<500 mm yr−1 rainfall), such as parts of Australia's Murray-Darling Basin (MDB). In this unique study, hydrogeological measurements and estimations of the historic water balance of crops grown on overlying Grey Vertosols were combined to estimate the contribution of deep drainage below crop roots to recharge and salinization of shallow groundwater. Soil sampling at two sites on the alluvial flood plain of the Lower Namoi catchment revealed significant peaks in chloride concentrations at 0.8–1.2 m depth under perennial vegetation and at 2.0–2.5 m depth under continuous cropping indicating deep drainage and salt leaching since conversion to cropping. Total salt loads of 91–229 t ha−1 NaCl equivalent were measured for perennial vegetation and cropping, with salinity to ≥10 m depth that is not detected by shallow soil surveys. Groundwater salinity varied spatially from 910 to 2430 mS m−1 at 21 to 37 m depth (N = 5), whereas deeper groundwater was less saline (290 mS m−1) with use restricted to livestock and rural domestic supplies in this area. The Agricultural Production Systems Simulator (APSIM) software package predicted deep drainage of 3.3–9.5 mm yr−1 (0.7–2.1% rainfall) based on site records of grain yields, rainfall, salt leaching and soil properties. Predicted deep drainage was highly episodic, dependent on rainfall and antecedent, and over a 39 yr period was restricted mainly to the record wet winter of 1998. During the study period, groundwater levels were unresponsive to major rainfall events (70 and 190 mm total), and most piezometers at about 18 m depth remained dry. In this area, at this time, recharge negligible due to low rainfall and large potential evapotranspiration, transient hydrological conditionsafter changes in land use and a thick clay dominated vadose zone. This is in contrast to regional groundwater modelling that assumes annual recharge of 0.5% of rainfall. Importantly, it was found that leaching from episodic deep drainage could not cause discharge of saline groundwater in the area, since the water table was several meters below the incised river bed.
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Solangi, Kashif Ali, Altaf Ali Siyal, Yanyou Wu, Bilawal Abbasi, Farheen Solangi, Imran Ali Lakhiar und Guiyao Zhou. „An Assessment of the Spatial and Temporal Distribution of Soil Salinity in Combination with Field and Satellite Data: A Case Study in Sujawal District“. Agronomy 9, Nr. 12 (10.12.2019): 869. http://dx.doi.org/10.3390/agronomy9120869.
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Soil salinization is a serious environmental issue that significantly influences crop yield and soil fertility, especially in coastal areas. Numerous studies have been conducted on the salinity status in Pakistan. Information about the geospatial and temporal distribution of salinity in the Sujawal district is still lacking. The present study examines the soil salinity status and the impact of seawater intrusion in the entire district from 1990 to 2017 using field and remote sensing (RS) data. In addition, 210 soil samples at different depths (0–20, 20–40, and 40–60 cm) were collected from randomly selected locations for lab measurements of physiochemical properties. The results showed that the soil texture classes were mainly fine to medium particles. The samples collected at the 0–20 cm depth were mostly dominated by three textural classes of soil: clay at 19.5%, clay loam at 25.6%, and loam at 32.9%. The electrical conductivity (EC) of 65.7% soil samples collected from the top layer exceeded the normal range. The quantitative results indicated that the exchangeable sodium percentage (ESP) ranged between 1.38 and 64.58, and 72.2% of the top layer soil samples had ESP >15, while 81.5% of soil samples were in the normal range of soil pH. Furthermore, the results indicated that the vegetation decreased by 8.6% from 1990 to 2017, while barren land and water bodies increased significantly, by approximately 4.4% and 4.2%, respectively. The extreme and high salinity classes were characterized by high contents of soluble salt on the surface in the Jati and Shah Bandar subdistricts. In addition, the soil EC values at the 0–20 cm depth were significantly correlated with the salinity index (S1). Therefore, it was concluded that more than 50% of the top layer of soil was affected by salinity due to seawater intrusion, low rainfall, climate change, and erratic river flow. It is suggested that remote sensing (RS) data are more suitable for the detection of the soil salinity status of a region and impose a lower cost compared to other conventional approaches. However, this study could provide significant knowledge to land managers, policymakers, and government officials to allow them to take action to implement salinity control measures in the study area.
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Faulkner, Patricia C., Ruth M. Elsey, David Hala und Lene H. Petersen. „Correlations between environmental salinity levels, blood biochemistry parameters, and steroid hormones in wild juvenile American alligators (Alligator mississippiensis)“. Scientific Reports 11, Nr. 1 (26.07.2021). http://dx.doi.org/10.1038/s41598-021-94557-y.
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AbstractAmerican alligators (Alligator mississippiensis) inhabit freshwater wetlands that are vulnerable to salinization caused by anthropogenic alterations to freshwater flow, in addition to storm surges, sea level rise, and droughts. Salinization of coastal freshwater habitats is a growing concern in a changing climate due to increased frequency and intensity of storm surges and drought conditions. This study opportunistically sampled juvenile male and female wild alligators in various salinities each month excluding November, December, and January for one year at Rockefeller Wildlife Refuge in coastal Louisiana. Blood plasma biochemistry parameters including electrolyte levels were subsequently measured. In addition, levels of various renin–angiotensin–aldosterone system hormones, glucocorticoids, androgens, estrogens, and progestogens were analyzed using liquid chromatography and tandem mass spectrometry. Only males were sampled in hyperosmotic environments (> 10‰) during dry conditions in late summer 2018. In juvenile males, plasma Na+, Cl−, and the progestogen 17α,20β-dihydroxypregnenone were significantly and positively correlated with environmental salinity. However, variation in glucocorticoids, androgens, and estrogens were not associated with hypersaline water while sex steroids showed significant seasonal variation. This study demonstrated significant correlation of environmental salinity with electrolyte levels and a sex steroid in wild juvenile alligators, and to our knowledge represents the first measurement of 17α,20β-dihydroxypregnenone in alligators.
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Mastrorillo, Lucia, Roberto Mazza, Paola Tuccimei, Carlo Rosa und Renato Matteucci. „Groundwater monitoring in the archaeological site of Ostia Antica (Rome, Italy): first results“. Acque Sotterranee - Italian Journal of Groundwater, 14.06.2016. http://dx.doi.org/10.7343/as-2016-192.
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The archaeological site of Ostia Antica hosts the ruins of the ancient roman city called Ostia founded in the VII century B.C. near the mouth of Tiber River. The area was strategically important for Rome, not only for the control of the river, but also for some salt marshes (Ostia Pound). During the XIX century, the whole area was reclaimed and the salt production stopped. Nowadays drainage canals and pumps avoid the flood of zones placed below sea level, keeping dewatering below the ground surface. In February 2014, the site was largely flooded after an exceptional rainfall event and the Superintendence for Archaeological Heritage of Rome ordered the closure for 15 days. Few months later (July 2014) a groundwater monitoring project started with the aim of studying the aquifer response to local rainfall and prevent future damage and groundwater flooding. The activity consisted in water-table monitoring, groundwater electrical conductivity (EC) and temperature continuous measurements, coupled with chemical analysis of major ions. Preliminary results shows the link between water table fluctuations and rainfall distributions. The average elevation of the archaeological area is about 2,5 m a.s.l. and the local water-table depth is of about 0,5 m a.s.l.; groundwater flows from the Tiber River to the reclaimed area according to regional flowpath. Groundwater sampled from three wells is Ca-HCO3 freshwater (600 - 1000 μS/cm), while the sample collected from a well located close to ancient salt storage warehouse (now Ostia Antica museum), is Na-Cl brackish water (about 4000 μS/cm). The chemical evolution of groundwater from summer to winter suggested a possible lateral inflow from the Tiber River, affected by salt-wedge intrusion. The inflow of Ca-Cl, SO4 Tiber’s water with an intermediate salinity could determine salinization of Ca-HCO3 freshwaters and refreshing of Na-Cl brackish water.
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Mastrorillo, Lucia, Roberto Mazza und Stefano Viaroli. „Recharge process of a dune aquifer (Roman coast, Italy)“. Acque Sotterranee - Italian Journal of Groundwater, 20.12.2018. http://dx.doi.org/10.7343/as-2018-356.
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The urban development plan of left bank of the Tiber river Delta preserved a 9 km2 stretch of dune belt with a monumental coastal pine forest (Castelfusano forest), which is nowadays portion of a natural reserve managed by Municipality of Rome. The forest was largely destroyed by a first huge fire in July 2000 and by another one in July 2017. A reforestation project involved the installation of a monitoring network composed by 21 piezometers to check the groundwater depth and its degree of salinization after the 2000 fire. By examining series of water head measurements and chemical -physical parameters carried out from 2002 up today, the current research aims to analyse the effects of 2000 and 2017 fires on the recharge process. The first result consists in the definition of the hydrogeological conceptual models of the dune aquifer: a shallow fresh aquifer overlapping two deeper confined salinized aquifers. The comparison between the amount of the yearly recharge, evaluated in different periods, showed a significant recharge rate decrease (about 36%) to be attributed likely at the 2000 fire effect. The research is still ongoing in order to verify and detail the changes of the recharge processes induced by the 2000 and 2017 fires.