Water Salt Concentration Research Articles

Spatio-temporal salinity dynamics and yield response of rice in water-seeded rice fields

The scarcity of high quality irrigation water is a global issue facing rice growers, forcing many to adopt water management systems that may result in increased salinity and yield reductions. While salt concentrations in field water have been shown to vary depending on water management, the distribution and build-up patterns of dissolved salts are unclear. This study was conducted to elucidate the within field spatial and temporal salinity dynamics in water-seeded rice cropping systems, and to assess current salinity thresholds for rice yield reduction. In this two-year study, water and soil salinity concentrations of eleven field sites were monitored weekly, with three sampling points being established in the top, middle and bottom basins of each field. There was a consistent spatio-temporal water salinity pattern among all fields: the maximum water salinity within a field occurred during week 2 to week 7 after planting, and was greatest farther from the irrigation inlet and where soil salinity was high. A model developed to predict water salinity within a field indicates that, averaged over an entire growing season, the position within a field contributed to 82% of the variation explained by the model, while preseason soil salinity contributed to 18%. Importantly, field water salinity was determined to be the most sensitive salinity metric for rice yield, as preseason soil salinity was a poor predictor of yield loss. The threshold field water salinity concentration was estimated at 0.88dSm−1, lower than the previous report of 1.9dSm−1. These results illustrate the ability to predict water salinity in a rice field with few parameters, while highlighting the importance of field water salinity as the main salinity metric for rice cropping systems.

Strong release of viruses in fracture flow in response to a perturbation in ionic strength: Filtration/retention tests and modeling

Effluents derived from a municipal wastewater treatment plant were used for virus filtration/retention experiments by using a horizontal laboratory filter. Filtration tests were performed to examine how soil geochemical heterogeneity and fracture patterns affected the transport of viruses in groundwater in order to model the influence of reductive perturbations in ionic strength (IS) during wastewater filtration. Although perturbations of IS and velocity are known to result in resuspension of colloids, we found that the effect of soil geochemical heterogeneity can produce strong and instantaneous virus releases in fractured aquifers, likely an internal additional source of viruses. Sixteen limestone slabs were packed in a PVC box filter at the Bari Laboratory (South Italy) to replicate wastewater filtration throughout a fractured medium similar to the Bari carbonate aquifer. Terra rossa, which is an aggregate of sand, silt and clay, was unevenly spread on the surface of each limestone slab within the filter. Since the mineralogical composition of terra rossa includes iron (hematite, magnetite, and goethite) oxides, the soil exhibited localized unfavorable colloid/collector interactions for attachment. In contrast, soil-free parts of the fracture surfaces maintained favorable colloid/collector interactions. We found in our experiments that the lowering of IS due to the reduction of water salt content, which could occur during runoff injections after rainfall, might be sufficient to cause strong detachment of viruses from fracture surfaces, allowing further migration into the groundwater. The model in this work can predict the count and pathways of released viruses in groundwater fractures under soil geochemical heterogeneity and originated by reductions of IS, by using analytical solutions.

Hydrate anti-agglomeration and synergy effect in normal octane at varying water cuts and salt concentrations

Abstract Anti-agglomeration is a promising approach to address hydrate risks in oil and gas flowlines from the deep sea. Salt concentration of the coproduced water with hydrocarbons is known to affect anti-agglomeration. Most studies report improvement in efficiency of anti-agglomeration but some authors report a decrease from salts. In this work, the effect of water cut (ratio of aqueous phase to total liquid) and NaCl concentration on the effectiveness of the cocamidopropyl dimethylamine anti-agglomerant (AA) are investigated in normal octane and methane systems. We also investigate the synergic effect of a cosurfactant (Span 80) in improving the performance of the AA at water cuts of 10%–30%. A likely mechanism of the synergism is suggested: the co-surfactant (Span 80) promotes the dispersion of water droplets in the oil phase and the AA prevents the agglomeration of the hydrate particles. We investigate emulsion formation and the phase behaviour of octane/brine/AA/Span 80 emulsion to shed light on the mechanisms at play. A solid-like fluid which hardly moves under gravity is observed when the normal octane and water/brine and the anti-agglomerant are mixed at a water cut of 95%. The solid-like behaviour which is attributed to flocculation can be remedied by the introduction of alcohols in the solution. There are similarities in emulsion formation and hydrate anti-agglomeration of normal octane and a condensate liquid which was investigated recently and there are also major differences.

Simultaneous analysis of electrosorption capacity and kinetics for CDI desalination using different electrode configurations

Capacitive deionization (CDI) offers an affordable technology for the reduction of salt concentrations in brackish water. However, there are still drawbacks concerning electrode capacity and energy consumption, compared to other well-established technologies such as reverse osmosis or electrodialysis. This study investigates high-adsorption electrodes based on polyaniline-activated carbon, applying different configurations (symmetric and asymmetric electrodes, and membrane CDI) to optimize electrosorption capacity and energy consumption. A new approach called OSR (optimized salt removal) is proposed, based on simultaneous analysis of the electrosorption capacity and the adsorption/desorption kinetics. This technique was used to evaluate different electrode configurations. The best performance was obtained using MCDI, which improved the electrode capacity from 14.9 to 20.0mgg−1, while reducing the specific energy consumption by 21%. It was demonstrated that the performance of the electrode depended on both the specific adsorption capacity (SAC) and the electrosorption/desorption kinetics. Fitting the electrosorption and desorption curves using a pseudo-first order kinetic model and applying the OSR method showed that the best desalination was achieved using MCDI at 1.2V. This configuration did not present the highest SAC or the fastest electrosorption/desorption kinetics, but a good balance was obtained between these two variables.

Energy-environment-economic investigations on evacuated active multiple stage series flow solar distillation unit for potable water production

Multi stage solar distillation units are well known for their higher distillate productivity and are capable of fulfilling the potable water requirements of families in remote, rural, and coastal regions. In this article, active multiple stage series flow solar distillation unit has been proposed for desalting saline water and its performance, environmental benefits and economic feasibility were assessed by carrying out 3E (Energy-Environment-Economic) analyses using the developed mathematical model. Better performance was observed for the distillation unit with five distillation stages, two solar collectors connected in parallel configuration and saline water mass flow rate of 135.0kg/d and 75.0kg/d, during summer and winter seasons. Low-pressure operation in combination with evaporative cooling of condenser of last stage has enhanced the annual average daily distillate productivity from 12.60kg/d to 48.80kg/d. Distillate production was found to drop from 48.80kg/d to 38.90kg/d with the increase in salt concentration of saline water from 0wt% to 10wt%. Energy payback time of the unit desalting saline water with 5wt% salt concentration was within 1.0yr and the unit can mitigate nearly 221.80 tons of CO2 emission, 1594.73kg of SO2 emission and 651.37kg of NO emission from Indian coal based power plants during its 20yrs lifespan under 250 clear day operation. Increased salt concentration in saline water reduces the emission mitigation potential and increases the energy payback time of the proposed distillation unit. Distillate production cost was increased by 16.0% for every 5wt% increase in salt concentration. Amount invested in the unit can be regained with in 3.56yr irrespective of interest rate for distilled water selling price of 0.06USD/L (Rs. 3.91/L).

Oxygen consumption remains stable while ammonia excretion is reduced upon short time exposure to high salinity in Macrobrachium acanthurus (Caridae: Palaemonidae), a recent freshwater colonizer

ABSTRACT Palaemonid shrimps occur in the tropical and temperate regions of South America and the Indo-Pacific, in brackish/freshwater habitats, and marine coastal areas. They form a clade that recently (i.e., ~30 mya) invaded freshwater, and one included genus, Macrobrachium Bate, 1868, is especially successful in limnic habitats. Adult Macrobrachium acanthurus (Wiegmann, 1836) dwell in coastal freshwaters, have diadromous habit, and need brackish water to develop. Thus, they are widely recognized as euryhaline. Here we test how this species responds to a short-term exposure to increased salinity. We hypothesized that abrupt exposure to high salinity would result in reduced gill ventilation/perfusion and decreased oxygen consumption. Shrimps were subjected to control (0 psu) and experimental salinities (10, 20, 30 psu), for four and eight hours (n = 8 in each group). The water in the experimental containers was saturated with oxygen before the beginning of the experiment; aeration was interrupted before placing the shrimp in the experimental container. Dissolved oxygen (DO), ammonia concentration, and pH were measured from the aquaria water, at the start and end of each experiment. After exposure, the shrimp’s hemolymph was sampled for lactate and osmolality assays. Muscle tissue was sampled for hydration content (Muscle Water Content, MWC). Oxygen consumption was not reduced and hemolymph lactate did not increase with increased salinity. The pH of the water decreased with time, under all conditions. Ammonia excretion decreased with increased salinity. Hemolymph osmolality and MWC remained stable at 10 and 20 psu, but osmolality increased (~50%) and MWC decreased (~4%) at 30 psu. The expected reduction in oxygen consumption was not observed. This shrimp is able to tolerate significant changes in water salt concentrations for a few hours by keeping its metabolism in aerobic mode, and putatively shutting down branchial salt uptake to avoid massive salt load, thus remaining strongly hyposmotic. Aerobic metabolism may be involved in the maintainance of cell volume, concomitant with reduced protein/aminoacid catabolism upon increase in salinity. More studies should be conducted to broaden our knowledge on palaemonid hyporegulation.

Long-term precipitation-driven salinity change in a saline, peat-forming wetland in the Athabasca Oil Sands Region, Canada: a diatom-based paleolimnological study

Saline wetlands represent potential natural analogs for reclaimed wetlands in the Athabasca Oil Sands Region (AOSR). Thus, an understanding of the drivers of salinity changes in natural wetlands can provide insight into how reconstructed peatlands in the AOSR may evolve given that they are constructed with saline oil sands reclamation materials. Here, we investigate the nature of salinity changes from the analysis of sediment cores at three ponds situated within a saline peat-forming wetland near Fort McMurray (Alberta). Past changes in salinity were reconstructed using weighted-averaging transfer functions based on diatoms and an environmental dataset from 32 saline boreal ponds. Results reveal complex “precipitation—surface water—groundwater” interactions associated with differences in the hydrologic functioning of the studied ponds, and their connectivity with shallow groundwater aquifers and adjacent wetlands. Relationships between cumulative departure from mean precipitation and DI-salinity suggest that precipitation may control salinity both directly and indirectly. In ponds recharged predominantly by meteoric water, precipitation may govern salinity directly by dilution of salt content in water, so that rises in precipitation result in a salinity decline. In ponds situated within a saline groundwater discharge zone, salinity may be influenced by precipitation indirectly through recharge of the saline aquifer, so increases in precipitation lead to rises in salinity. Our study suggests that complex salinity response to precipitation change, coupled with notable range of salinity fluctuation within natural saline fens should be considered while designing saline constructed wetlands and predicting their potential resilience under climate change.

Experimental study of formation and dynamics of cavitation bubbles and acoustic flows in NaCl, KCl water solutions

The acoustic flows and the phenomena associated with them arising under the action of ultrasound of different power on distilled water and aqueous solutions of a mixture of NaCl and KCl salts of various concentrations are studied experimentally. It is found that in the distilled water, under the action of ultrasound, the appearance of inertial and non-inertial cavitation bubbles takes place, then the formation of stable clusters, the distance between which depends on the power of the ultrasound source is observed. Experiments show that an increase in the mass concentration of salts in water leads to the decrease in the average diameter of the arising inertial cavitation bubbles and to the gradual decrease in their number, up to an almost complete disappearance at nearly 13% of the concentration of the salt mixture in the water.

A consortium of immobilized rhodococci for oilfield wastewater treatment in a column bioreactor

The possible use of a consortium of actinobacteria from the genus Rhodococcus immobilized on a polymeric carrier has been investigated for oilfield wastewater treatment in a bioreactor. It has been found that Rhodococcus opacus IEGM 263 and Rhodococcus ruber IEGM 231 cells remain viable at high concentrations of mineral salts in water and are able to oxidize oil hydrocarbons up to 62–81%. It has been shown that the consortium of rhodococci was more efficient in the elimination of hydrocarbons from wastewater than monocultures.

Improvement of water desalination technologies in reverse osmosis plants

The strengthening of requirements for the protection of surface-water sources and increases in the cost of reagents lead to the necessity of using membrane (especially, reverse osmosis) technologies of water desalination as an alternative to ion-exchange technologies. The peculiarities of using reverse osmosis technologies in the desalination of waters with an increased salinity have been discussed. An analogy has been made between the dependence of the adsorptive capacity of ion-exchange resins on the reagent consumption during ion exchange and the dependence of the specific ion flux on the voltage in the electrodialysis and productivity of membrane elements on the excess of the pressure of source water over the osmotic pressure in reverse osmosis. It has been proposed to regulate the number of water desalination steps in reverse osmosis plants, which makes it possible to flexibly change the productivity of equipment and the level of desalinization, depending on the requirements for the technological process. It is shown that the selectivity of reverse osmotic membranes with respect to bivalent ions (calcium, magnesium, and sulfates) is approximately four times higher than the selectivity with respect to monovalent ions (sodium and chlorine). The process of desalination in reverse osmosis plants depends on operation factors, such as the salt content and ion composition of source water, the salt content of the concentrate, and the temperatures of solution and operating pressure, and the design features of devices, such as the length of the motion of the desalination water flux, the distance between membranes, and types of membranes and turbulators (spacers). To assess the influence of separate parameters on the process of reverse osmosis desalination of water solutions, we derived criteria equations by compiling problem solution matrices on the basis of the dimensional method, taking into account the Huntley complement. The operation of membrane elements was analyzed and the dependence of the output of desalinated water (permeate) through the membranes on the pressure of influent water for desalination and the dependence of the permeate output on the water viscosity and the dependence of the specific permeate output on the velocity and length of the motion of the desalination water flux were built. The values of the optimum pressure of source influent water for desalination in a reverse osmosis device were found. Provided the current prices for membrane elements (800 to 1200 USD) and cost of electricity (0.06–0.1 USD), the optimum pressure is 1.0 to 1.4 MPa.

Pulsed field evaporation of ions from polar solutions

An implementation of a technique for studying the release of ions from polar solutions under the action of electric field pulses is presented. A track membrane with nanoscale channels is used in this technique to stabilize the solution surface. The dependences of the ion yield on the parameters of extracting voltage pulses, as well as on the KI salt concentration in water−glycerol solutions have been obtained. The main advantage of the use of short pulses over a constant voltage technique is the possibility of expanding the range of the field strengths extracting ions from a solution without the risk that the solution leaks to the vacuum side of the membrane. In addition, a high stability of the extraction process is provided and the continuous operating time without membrane replacement is increased. The formation of the extraction field at the end of the channel due to the tip effect provides a fast start of the extraction process immediately after applying a voltage pulse, which also simplifies work with the membrane interface.

Controllable preparation of a hydrophilic/ion-exchange mixed-mode stationary phase by surface-initiated atom transfer radical polymerization using a mixture of two functional monomers.

Mixed-mode chromatographic stationary phases require functionalization with at least two functional groups to yield multiple interactions with analytes. Departing from reported methods, a mixture of two different monomers, glycidyl methacrylate and 2-dimethylaminoethylmethacrylate, was grafted onto the surface of silica by a one-step surface-initiated atom transfer radical polymerization to prepare a novel hydrophilic interaction/anion-exchange mixed-mode chromatographic stationary phase. The grafted amounts of functional groups were controlled via varying the ratio of monomers in the polymerization system. The influences of water content, salt concentration and pH in the mobile phase were investigated to illustrate the mixed interaction between the stationary phase and analytes. The retention of various solutes on three columns, especially acidic and basic solutes, showed an obvious dependence on the ratio of the two monomers in the polymerization system. The results indicated that the strategy proposed in this work was beneficial to develop various types of mixed-mode chromatographic stationary phases with adjustable selectivity to meet the needs of complex samples. Finally, the column was successfully employed in the isolation of melamine in liquid milk.

Hydrosalinity balance and critical ratio of drainage to irrigation (RDI) for salt balance in Weigan River irrigation district of the Tarim basin (China)

The analysis of the principle of salt mass balance in irrigation districts is the foundation for the rational drainage system design and its effective evaluation. The salt balance of the Weigan River irrigation district is analyzed using annual measured data. Factors affecting the ratio of drainage to irrigation (RDI) and methods for determining this ratio are discussed. The results show that RDI is related to the volume and salt content of irrigation water and drainage water. The critical RDI for the Weigan River irrigation district is 9.29%. It is necessary to achieve a certain level of percolation to maintain the hydrosalinity balance when planning irrigation schedules and managing irrigation and drainage. Moreover, urgent improvement of the current drainage system is required to ensure that the actual RDI is greater than the critical RDI in the irrigation district. From 1994, the irrigation district turned from salt accumulation to desalinization, and the ratio of drainage to irrigation tended to optimal value.

REDUCING ROAD SALT APPLICATION BY CONSIDERING WINTER MAINTENANCE NEEDS IN PARKING LOT DESIGN

INTRODUCTION Winter snow and ice can have a significant impact on our mobility, whether on foot or by car. Alongside plowing, arguably the greatest tool in combating snow and ice is salt. The most commonly used salt for winter maintenance is Sodium Chloride (NaCl), the same salt used in food and water softeners, is applied to roads, sidewalks, and parking lots as it is an effective deicer when temperatures are between 0°C and −12°C. Studies have shown that deicing with salt reduces accidents by 88% and injuries by 85% (Salt Institute 2017). The effectiveness of road salt, as well as its relative affordability, means that as much as four million tonnes may be applied annually in Canada for deicing (Environment Canada 2012). However, while salt is relatively inexpensive to purchase, there are a number of external costs that are becoming increasingly apparent. These include corrosion of vehicles and infrastructure like concrete, bridges, and water mains; damage and staining to the interior and exterior of bu...

Modelling the Physical System of Belawan Estuary

Belawan estuary represents one of the most complex and fascinating mixed environments of sea and land, where not only habitat of rich biodiversity but also international seaport infrastructure are at stake. It is therefore a matter of considerable importance to understand the physical system which characterizes the dynamics of the estuarine water. The purpose of this study is to model the changing water depths, tidal currents, salt, temperature and sediment concentration over a long stretch of Belawan estuary on an hourly basis. The first essential step is to define the bathymetry based on which other physical parameters are simulated. The study is accomplished by building working computer modules which simplify and model the systems complexities. It should be noted that model validation and improvement is the subject of the next study.

Evaluating the effects of irrigation water salinity on water movement, crop yield and water use efficiency by means of a coupled hydrologic/crop growth model

Numerical simulation is an efficient approach for investigating the salt and water movement through soil profile and predicting of crop response to soil water deficit and salinity. In this study a coupled model that describes the soil water and solute transport by means of HYDRUS-1D model and crop growth process by means of growth module of EPIC was used. The model was calibrated and validated against field data, collected during two growing seasons in field plots of winter wheat irrigated with four levels of irrigation amount and water salinity of 5dsm−1 at the Fengqiu State Key Agro-Ecological Experimental Station, in North China Plain. The model was also used to evaluate the salinity stress on evapotranspiration (ET), grain yield and water use efficiency (WUE) and long-term use of saline water on grain yield and salt accumulation. Visual inspection and the obtained statistical parameters values showed that good agreement between measured and simulated data of soil water content, salt concentration, ET and grain yield. Evapotranspiration values of winter wheat were reduced under salinity stress conditions, mainly by reducing crop transpiration. The grain yields were reduced due to salinity stress, but the change trend of WUE was associated with precipitation amount. Increasing per saline water irrigation amount is an effective way to reduce the WUE decline rate under the low rainfall growing season as like that in simulation year. The average of ten years grain yield confirmed that a yield potential exceeding 86% could be maintained by saline water with 5dsm−1 when per irrigation volume more than 0.8 E, E denotes evaporation from an uncovered, 20cm diameter pan positioned 0–5cm above the crop canopy. There has a slight salt build-up after ten years simulation, and the quantity of salt accumulation decreased with the increase of irrigation volume. Thus, more attention should be paid to the sustainability of irrigated agriculture with low irrigation volume when using saline water irrigation. On the whole, field observations combined with the coupled model could be used to evaluate different agricultural managements on grain yield and soil salinity.

An Experimental Study on Relationship among Water Sorptivity, Pore Characteristics, and Salt Concentration in Concrete

In this work, the sorptivity properties of concrete with varioustypes of supplementary cementitious materials (SCMs) curedat three different curing regimes was investigated using thegravimetric method. In parallel, the effects of four differentconcentrations of sodium chloride solution on the sorptivity ofconcrete were studied using both gravimetric and electronicmethods. The results show that the incorporation of SCMsreduces the sorptivity of concrete when sufficient moisture curingis provided; otherwise, it exacerbates sorptivity. Nevertheless,there exists a strong correlation between the sorptivitycoefficient and threshold pore size of concrete measured bymercury intrusion porosimetry. The gravimetric and electronicmethods show different trends regarding the effects of liquidproperties on sorptivity, probably because the gravimetricmethod cannot differentiate the weight of water from salts duringthe measurements.

Correction factor to account for dispersion in sharp-interface models of terrestrial freshwater lenses and active seawater intrusion

In this paper, a recent analytical solution that describes the steady-state extent of freshwater lenses adjacent to gaining rivers in saline aquifers is improved by applying an empirical correction for dispersive effects. Coastal aquifers experiencing active seawater intrusion (i.e., seawater is flowing inland) are presented as an analogous situation to the terrestrial freshwater lens problem, although the inland boundary in the coastal aquifer situation must represent both a source of freshwater and an outlet of saline groundwater. This condition corresponds to the freshwater river in the terrestrial case. The empirical correction developed in this research applies to situations of flowing saltwater and static freshwater lenses, although freshwater recirculation within the lens is a prominent consequence of dispersive effects, just as seawater recirculates within the stable wedges of coastal aquifers. The correction is a modification of a previous dispersive correction for Ghyben-Herzberg approximations of seawater intrusion (i.e., stable seawater wedges). Comparison between the sharp interface from the modified analytical solution and the 50% saltwater concentration from numerical modelling, using a range of parameter combinations, demonstrates the applicability of both the original analytical solution and its corrected form. The dispersive correction allows for a prediction of the depth to the middle of the mixing zone within about 0.3m of numerically derived values, at least on average for the cases considered here. It is demonstrated that the uncorrected form of the analytical solution should be used to calculate saltwater flow rates, which closely match those obtained through numerical simulation. Thus, a combination of the unmodified and corrected analytical solutions should be utilized to explore both the saltwater fluxes and lens extent, depending on the dispersiveness of the problem. The new method developed in this paper is simple to apply and offers a wider range of application relative to the previous sharp-interface freshwater lens solution.

Influence of redox potential of different water quality on the human blood

The problem of influence of redox potential of water on human blood is considered and some of research results in this area are given. Results of clinical experiments indicate a positive therapeutic effect of water consumption with the negative value of the redox potential. However, the influence of salt content of such water on the human body isn’t analyzed. Distilled, tap and natural mineral medical-table water «Polyana Kvasova» (Ukraine) are analyzed. Distilled water doesn’t have drinking water properties. The value of the total salt content of «Polyana Kvasova» mineral water far exceeds the standard value of allowable salt content in the water. Tap water (Lviv, Ukraine) is characterized by physiological full value of mineral composition. All water samples in accordance with pH value, except distilled water, meet drinking water quality indicators. The value of the redox potential is most favorable to the human body for «Polyana Kvasova» mineral water. The source water saturation with molecular hydrogen and activation in electric activator can reduce its redox potential for negative values. Change of the quality parameters for activated water (catholyte) indicates their non-compliance with drinking water indicators. Quality of hydrogen-saturated water hasn’t changed. Water consumption with negative redox potential improves blood condition of the experimenter compared to the reference Consumption of activated water (catholyte) has immunomodulatory effect rather than an antioxidant effect. The powerful antioxidant effect of hydrogen-saturated water is indicated. Blood state close to ideal is observed after consumption of natural mineral medical-table hydrogen-saturated water «Polyana Kvasova». Saturation of water with hydrogen can be considered as a method of improving drinking water quality and, thus, human health.

Durum Wheat Roots Adapt to Salinity Remodeling the Cellular Content of Nitrogen Metabolites and Sucrose

Plants are currently experiencing increasing salinity problems due to irrigation with brackish water. Moreover, in fields, roots can grow in soils which show spatial variation in water content and salt concentration, also because of the type of irrigation. Salinity impairs crop growth and productivity by inhibiting many physiological and metabolic processes, in particular nitrate uptake, translocation, and assimilation. Salinity determines an increase of sap osmolality from about 305 mOsmol kg−1 in control roots to about 530 mOsmol kg−1 in roots under salinity. Root cells adapt to salinity by sequestering sodium in the vacuole, as a cheap osmoticum, and showing a rearrangement of few nitrogen-containing metabolites and sucrose in the cytosol, both for osmotic adjustment and oxidative stress protection, thus providing plant viability even at low nitrate levels. Mainly glycine betaine and sucrose at low nitrate concentration, and glycine betaine, asparagine and proline at high nitrate levels can be assumed responsible for the osmotic adjustment of the cytosol, the assimilation of the excess of ammonium and the scavenging of ROS under salinity. High nitrate plants with half of the root system under salinity accumulate proline and glutamine in both control and salt stressed split roots, revealing that osmotic adjustment is not a regional effect in plants. The expression level and enzymatic activities of asparagine synthetase and Δ1-pyrroline-5-carboxylate synthetase, as well as other enzymatic activities of nitrogen and carbon metabolism, are analyzed.