شوری

About 70% of the total freshwater withdrawal from resources is used in the agricultural sector. Water and soil salinity is one of the most important problems in the agricultural sector in arid and semi-arid regions. In such areas that are facing water shortages, saline water is commonly used in irrigated lands and it will be of great help in preserving freshwater resources. Crop modeling in combination with field measurements is an efficient method to improve water productivity in the field and investigate the crop's biological response to different field conditions. Several crop models have been developed for crop growth simulation. Among these models, AquaCrop software has been widely studied in recent years. AquaCrop software is able to simulate the growth process under different conditions with few input data that can be easily measured in the field. Few studies have been conducted on saffron crop modeling with AquaCrop software, but this model has not yet been calibrated to simulate salinity during the growing season. This research was carried out to calibrate the AquaCrop software for simulating the variations of soil salinity in the root zone of two-year-old saffron. In addition, in the present study, the effect of different levels of salinity and the application of different levels of organic mulch and their mutual effect on the yield of daughter corms, biomass, and water productivity were investigated.

To calibrate the AquaCrop software for two-year saffron during the growing season in the research farm of the Ferdowsi University of Mashhad (FUM), growth parameters of saffron crop such as the soil moisture and salinity, the dry weight of daughter corms and the crop canopy cover were continuously measured during the growing season. Soil moisture and salinity were measured at least once a week, and the dry weight of daughter corms was measured biweekly. After model calibration, the accuracy of the model for simulating soil salinity during the growing season was evaluated by comparing the measured and simulated values. Statistical indicators of Pearson correlation coefficient, root mean square error, and Nash Sutcliffe model efficiency coefficient, were used to evaluate the accuracy of crop model simulation. The model was subsequently run for different initial conditions of soil salinity and irrigation water salinity. The dry weight of daughter corm, biomass, and ET water productivity were monitored for different conditions. Then, the model was run in the same conditions of water and soil salinity under the application of organic mulch, and the effect of mulch on the yield of daughter corms and evapotranspiration water productivity under salinity stress was investigated.

The statistical indicators between the measured and simulated values of soil moisture, canopy cover, and biomass approved the capability of AquaCrop for simulating saffron growth. Then, according to the measured salinity values of the root zone using the TDR sensor, AquaCrop was recalibrated to simulate soil salinity. Afterward, the changes in the measured salinity values of the root zone during the growing season were compared with the values simulated by AquaCrop. The Pearson correlation coefficient for measured and simulated soil salinity by software was 0.9 and the root mean square error was 0.086 dS m-1. Nash–Sutcliffe efficiency was 0.66, showing the high accuracy of AquaCrop for simulating soil salinity. The results of the crop growth simulation in saline conditions show the sensitivity of saffron to salinity. The results showed that under no initial salinity (0.5 dS m-1) in the soil, increasing the salinity of irrigation water from 1 dS m-1 to 4 dS m-1 caused a decrease of 3.7 % in the daughter corms weight. In addition, considering the initial salinity of 2 dS m-1, increasing the salinity of the irrigation water has a significant effect on reducing the daughter corm weight. In the presence of high-quality irrigation water (0.5 dS m-1), increasing the initial salinity of the soil from no salinity (0.5 dS m-1) to 4 dS m-1 caused a 38% decrease in the weight of daughter corms. The effect of organic mulch was also evaluated under saline water irrigation conditions. The results showed that the use of organic mulch with 100% coverage in water and soil salinity conditions equal to 4 dS m-1 can mitigate the effect of salinity stress by increasing 51% of daughter corm weight.

Water and soil salinity and its related problems are limiting factors in agricultural production in arid and semi-arid regions. The expansion of irrigation methods with saline water without proper management can lead to the risk of soil quality loss and in turn the loss of agricultural lands in the long term. In this research, the AquaCrop model was calibrated to simulate soil salinity during the saffron growing season, and the effect of organic mulch on soil and water salinity conditions was evaluated on the yield of daughter corms. The findings of this research will be of great help to farmers and water experts in improving the performance of saffron in saline soil and irrigation water.

A basic solution to reduce the harmful effects of salinity stress is to apply biochar, which can be improved by modifying and enriching it. For this purpose, a completely randomized design experiment with three replications was conducted with treatments including salinity (2 and 6 dS/m) and biochar prepared from landscape waste at four levels (zero and 5% without enrichment, 5% enrichment with selenium at the rate of 20 and 60 mg/kg). Biochar enrichment decreased soil pH. Enriched biochar at the level of 60 mg/kg increased soil salinity. The amount of soil organic carbon increased proportionally by increasing biochar. The lowest amount of phosphorus was observed in the treatment of saline soil without biochar at the rate of 2.47 mg/kg, and the highest amount was observed in the treatment of non-saline soil containing 5% enriched biochar at the level of 60 mg/kg at the rate of 3.55 mg/kg. The amount of available potassium showed an increasing trend with increasing salinity levels. Enriching biochar with selenium reduced the positive effects of biochar on increasing the amount of potassium, especially in saline soil. In non-saline soil, biochar enrichment increased soluble sodium by 16.6% compared to non enrichment biochar, and increasing the level of enrichment did not show a significant effect. The change in the amount of solutes in the soil changed its chemical characteristics, and these changes were manifested in different ways under the influence of biochar and the level of enrichment.

Evaluation of drainage systems helps researchers and planners to examine the strengths and weaknesses of these systems and improve them in future plans. For this reason, in the present study, the performance of the drainage system implemented in the Gamboa irrigation and drainage network, located in the agricultural lands of Hamidieh city, was evaluated. In this research, she investigated the changes in water table level and salinity exit from the soil profile and measured the design indicators of underground drains. In order to read the water level fluctuations of the reservoir, observation wells were installed at intervals of 0.3, 0.8, 1.5, 2.5 and 15 meters and in the middle of the underground drains. The installation intervals of the observation wells between two drainage lines were 1/4L, 2/4L, 3/4L and 25 meters from the drain outlet. The results showed that The average hydraulic conductivity value in fields was 0.95 in reality and 0.89 m/day in design conditions, and the drainage coefficient value was 2.36 in reality and 2.6 mm/day in design conditions. Also, the examination of the proposed relationships for the design of the drainage system showed that Damm's relationship had the highest accuracy and Van Schilfgaard's relationship had the highest error in determining the water level. The control index of the depth of the ponding surface was between 0.82 and 1.11 and the control index of salinity exit from the soil was acceptable between -0.3 and -0.9. Product performance index was obtained in the range of (0.86-0.78). In total, after four years of the implementation of this drainage system, the productivity of wheat production increased by 62% from 2.55 tons per hectare to 4.1 tons per hectare compared to the conditions without drainage.

Nowadays, salinity stress is the most important abiotic stress for plants, because in addition to reducing yield, it reduces the amount of fresh water and land that can be used for agriculture. By contrast, in soilless or hydroponic cultivation systems, plants are cultivated in an environment other than soil, in order to get to maximum plant density, improve yield and reduce soil contamination and nutrient uptake problems. Considering that tomato is a plant with high nutritional value and that it can be grown in different substrates, choosing a suitable substrate for cultivation that has the ability to reduce the effects of salinity is important. In order to study the effect of activated carbon and potassium-enriched nano zeolite as an adsorbent under salty conditions on yield, growth, physiological properties and water use efficiency of tomato.This experiment was performed as a factorial experiment in a completely randomized design with three replications in the Faculty of Agriculture and Natural Resources of the Persian Gulf in 2022 in greenhouse conditions with a temperature of 22 ± 5°C and a relative humidity of 50 to 70%. . The experiment consisted of two factors of cultivation bed and irrigation water salinity. Five types of culture media including basic culture media (cocopeat and perlite at 2/1v/v ) and the treatments of activated carbon and nanozeolite enriched with potassium at two levels of 15 and 30g of each adsorbent, which were added to the kg of basic culture medium. Salinity levels of water applied at three levels of 1.8, 3.5 and 5.5 dS/m of Hoagland solution. Salinity treatments were applied two weeks after the establishment of Adamino tomato seedlings in the culture bed, through the drip solution system, and continued until one week before the end of the experiment (120 days). The measured traits were total yield, average fruit weight, chlorophyll a, b and total, carotenoids, lycopene, vitamin C, TSS, TA of fruit extract, electrolyte leakage, relative content of leaf water, proline and water use efficiency.The results showed that with increasing salinity to 5.5 dS/m, tomato yield, fruit weight, relative leaf water content, chlorophyll a, b, and total chlorophyll, carotenoid content content and water use efficiency significantly decreased (p< 0.01), while the application of absorbent could had a better effect on these traits by reducing the effect of salinity. on the other hands, increasing salinity increased vitamin C, TSS, TA of fruit extract, electrolyte leakage, lycopene and proline of tomato shoots. Adverse effects of salinity on plant growth include osmotic stress, specific ion effects, and nutritional imbalance leading to morphological, physiological and biochemical disturbances. Our result showed that amending the substrate with activated carbon and potassium-enriched nanozeolite increased all studied traits of tomato except vitamin C at all salinity levels (p< 0.01). The highest yield of tomato (6.66 kg), fruit weight (96.33 g) and water use efficiency (27.75 kg/m3) were related to the treatment of 15 g/kg potassium-enriched in culture medium with the solution of 1.8 dS/m. The application of 15 g/kg activated carbon and 30 g/kg potassium-enriched nanozeolite of culture medium increased the yield and fruit weight by 45% and 28% respectively compared to the control treatment at the same salinity level. Zeolites consist of large open internal pores with a high cation-exchange capacity in crystal structure that result in high water holding capacity and nutrient retention. That improvement of the plant growth in zeolite-rich treatments may be associated with enhancement of macronutrient supplement and reduction of sodium uptake by plant root. In addition, In addition the potassium in nanozeolite and due to antagonistic relationship between potassium and sodium, caused the reduction of sodium absorption by the plant, so it moderates the negative effects of salinity stress and increases indicators related to growth and yield and water use efficiency of tomato. It seems that the use of activated carbon in this research has reduced the effects of salinity stress due to its high specific surface area and porous structure. In general, the results of this study show the beneficial effects of activated carbon and enriched nano zeolite on properties of tomatoes. In general, the results of this research show the beneficial effects of the application of activated carbon and potassium nano-enriched zeolite on the yield, phytochemical traits and water use efficiency of tomato under salinity stress conditions.

It is essential to know the water requirement, which is a function of the type of plant and meteorological parameters in order to irrigation scheduling. Due to the direct measurement of water consumption, weighting and drainage microlysimeters are the most accurate method for calculating evapotranspiration. As the access to weighting and drainage lysimeters in most agricultural fields is limited, determination of plant water requirement by calculating the reference evapotranspiration and plant coefficient is a common and widely used method. The objective of the present study was to determine the evapotranspiration and crop coefficient of safflower in conditions without water and salinity stresses and also in conditions with salinity and drought stress in greenhouse.

The present study was done as factorial in a form of completely randomized design with three replications in greenhouse research at Kashmar higher education institute. The experiment treatments were three irrigation regimes including 100, 75 and 50 percent of water requirement and four salinity levels including 0.7, 4, 8 and 12 dS m-1. In order to measuring safflower water requirement 36 pots were used as a microlysimetre. The pots were weighted and irrigated daily and soil deficit moisture was obtained through the difference of the pot weight at the time of irrigation with the weight of the same pot at the status of potted agricultural capacity. By dividing plant evapotranspiration in a specific time interval to reference plant evapotranspiration in the same time interval, the plant coefficient for the four stages of safflower growth was obtained. Graphs drawing and statistical analysis were done using Excel, SPSS and Sigma Plot software. 

The results of variance analysis of safflower evapotranspiration showed that salinity, drought, growth stage and their combined effects on evapotranspiration were significant at the probability level of one percent (P<0.01). With the increase of salinity and drought stress, plant evapotranspiration decreased significantly. The highest evapotranspiration during the growing season was occurred for the control treatment (i.e. the treatment without water and salinity deficit) by amount of 269.5 mm and the lowest amount of it was observed in the W2S3 treatment by amount of 102.2 mm. For all of the experimental treatments, the highest plant evapotranspiration was observed in the middle stage and the lowest of it was seen in the early stage of growth. The value of crop coefficient of safflower in the conditions without water and salinity deficit, in the initial, development, middle and final stages of growth was obtained as 0.55, 0.9, 1.26 and 0.85 respectively. Under severe drought and salinity stress, safflower crop coefficient decreased to 0.07, 0.18, 0.3, and 0.13, in the initial, development, middle, and final stages of growth respectively.

Due to the quantitative and qualitative reduction of underground water resources in most regions of the country, especially in the forbidden plain of Kashmir, accurate determination of the water requirements of agricultural and garden plants, including the valuable oilseed plant safflower, is of great importance. The use of weighting and drainage microlysimeters is considered as an accurate method in determining the evapotranspiration of plants, but the limited access to them in most agricultural fields has caused researchers and implementers of irrigation projects, both surface and pressurized irrigation, to calculate the water requirement of agricultural and garden plants used the crop coefficients presented in FAO irrigation and drainage paper No.56. The results of many researches have shown that the use of crop coefficients presented in FAO irrigation and drainage paper No.56 leads to overestimation or underestimation of the water requirement of plants compared to real and local conditions. Therefore, it is felt necessary to determine the crop coefficient based on local and climatic conditions. On the other hand, the effect of salinity and drought stress on this coefficient doubles the importance of studying and determining the crop coefficient in areas such as the critical forbidden plain of Kashmar, where irrigation water salinity and its quantitative decrease have endangered the agriculture of the region. Therefore, in order to properly and efficiently management of water resources, it is suggested to determine the crop coefficient in the conditions of salinity and drought stress for agricultural plants with high economic value such as safflower oilseed plant.

Wetlands are highly beneficial to human societies due to their positive environmental functions, direct and indirect functions, as well as their value as an asset. It has led to an increase in the attention given to their restoration and maintenance in different societies. Shadgan Wetland contains fresh-salty, and brackish water, and approximately 900 million cubic meters of Jarahi water resources enter Shadgean every year. The wetland is at risk of serious harm as a result of the developmental activities occurring around it, which are causing pollutants to enter the wetland and reducing the quantity of fresh water coming in. A number of factors contribute to the destruction of this wetland, including over-exploitation from its water resources, the discharge of urban waste within its limits, the fragmentation of the wetland as a result of road construction, the construction of stations to increase the pressure on electricity, gas and oil pipelines, as well as effluents from industries such as bread making, alcohol production, sugarcane cultivation and industry. The economic value of wetlands and climate regulation, flood prevention, protection of plant and animal diversity, beauty and inherent visual attractions of wetlands, tourist attractions, as well as creating an opportunity for migratory birds to nest and a place for scientific research are among the most important considerations in the design of a wetlands. The development of water resources schemes and the regulation of river flows are often recognized as the most serious threats to the ecological sustainability of rivers and wetlands.

This study attempts to determine the change in water salinity of Shadegan wetland in the last five decades using the electrical conductivity index due to the importance of Shadegan wetland in various ways. Finally, a relationship has been established between the area and the salinity of this significant wetland. Also, by using electrical conductivity data from 23 stations in the lagoon and with the help of satellite images and remote sensing techniques and interpolation methods (IDW), the changes of this index in the mentioned period were investigated, leading to a mathematical relationship.

According to the research results, upstream human activities, especially dam constructions and agricultural development projects, have had a great impact on the quantity and quality of the wetland. With climate change and drought, these effects have intensified, resulting in a reduction of the wetland level as well as an increase in the salinity of the wetland water. These changes can be observed both in terms of their temporal and spatial dimensions. Consequently, the results show the trend of increasing salinity from the southern parts to the north and also the greater manifestation of the increase in salinity in the southern parts due to the decrease in the incoming fresh water flow (more than twice). According to the results, there are three salinity levels in the wetland: saline, brackish water, and super salinity, and a salinity increase is observed in all three zones The present results and equations are used as an achievement by water and environment managers and they can estimate the EC of water in key and indicator stations and finally at the level of the wetland by measuring the size of the wetland using different technologies. So over time, the levels and zones of saline and super salinity have expanded, and the levels of brackish water have decreased. It is expected that this process will continue over time, resulting in the sea salt water advancing towards the wetland and increasing the amount of salinity within it.

According to this study, based on the relationship between salinity and the level of the wetland, as well as the water area of the wetland, it is possible to estimate its salinity in three zones. By measuring the salinity of water at several key stations within each of the three zones, the wetland's water level can be estimated. In monitoring, managing, and qualitatively protecting the wetland and consequently its species, this equation and its relationships can play an important role.

The objective of this research was to investigate the effects of surface, bubbler and drip irrigation methods on salinity distribution around pistachio trees under gardener management in a soil with sandy clay loam texture. For this purpose, an experiment in the form of split split plots with three treatments of irrigation methods in the main plot, the distance from the row of trees at four levels (0.5, 1, 2 and 3.5 meters) in the sub-plot and the depth of soil at four levels (0 to 30, 30 to 60, 60 to 90 and 90 to 120 cm) in the sub-sub plot in three replications was done. Then applied water and soil salinity during two crop years were measured. According to the results, the amount of applied water in border, drip and bubbler irrigation was 8150, 5060 and 6390 m3c/ha, respectively. The effect of irrigation methods and distances from trees on soil salinity was significant at 1% level and showed that drip irrigation is superior to other methods. Salt distribution at different distances from the trees row also showed a significant difference. Solutes accumulation under drip irrigation has started in surface layer at the edge of the wet environment and at a distance of 70 to 80 cm from the row of trees. Accordingly, the drip irrigation is one of the suitable irrigation methods for pistachio gardens, under properly designed, implemented and operated and soil sustainability consideration, and it is a suitable alternative to the conventional surface irrigation. In drip irrigation, the amount of irrigation water was 38% less than the surface irrigation. It is obvious that in the areas where the irrigation water is not a good quality and the effective annual rainfall unable to leaching the soil, the soil should be leaching annually using the surface irrigation method.

In this study, the effect of shallow and saline groundwater on the yield andparameters of quinoa in the greenhouse environment in two crop years 2018 and 2019 was investigated. The experiment was conducted in the form of factorial design of randomized complete blocks with 3 replications. The applied treatments included shallow (with depths of 0.6, 0.8 and 1.1 m) and saline (with salinity levels of 1,2, 6 and 10 decisiemens/meter of NaCl salt). The results showed that with the increase of water salinity from 1 to 10 decisiemens/meter and with the increase of the depth of the groundwater level, the percentage of groundwater contribution and the contribution of groundwater decreased significantly. The percentage of underground water participation for different salinity levels of 1, 2, 6 and 10 decisiemens/m in the depths of the water table 0.6, 0.8 and 1.1 meters respectively (37.43, 55.51, 71.12), (35/84, 51.21, 66.68,), (32.57, 46.92, 60.1397) and (30.15, 43/03, 56.93) were obtained. the increase in salinity caused a decrease in biological yield and an increase in the depth of the ponding surface caused an increase in biological yield and grain yield.The general results of the research showed that in none of the treatments, the water requirement of the plant was never provided by underground water in a hundred percent way, and a part of the water requirement of the plant was always supplied through irrigation during the growth period. It can also be said that the use of shallow and salty underground water resources (salinity less than 2 decisiemens/meter) in order to meet the water needs of the quinoa plant can reduce the amount of irrigation and contribute to the evaporation and transpiration of the plant

The reduction of water resources due to the issue of global climate change and population growth is one of the most critical issues facing the designers and planners of the development of green spaces in cities. Against these challenges, there is an urgent need to improve the efficiency of water consumption and chain use of water resources with suitable options. Due to the significant volume of urban wastewater Effluent, its reuse in green space irrigation is important from the point of view of water resource management from an ecological and economic point of view. The effect of the Parand city wastewater treatment plant on the chemical properties of soil under the cultivation of three types of cover crops (Frankinia (FR), Festuca (FE), Dichondra (DI)) in a bed with sandy loam soil is investigated. This study was conducted as a factorial experiment based on a completely randomized design using mixing of water and Effluent at 4 levels with irrigation treatments of zero (control), 50, 75, and 100% compared to fresh water and 3 replications, and then the soil chemistry characteristics such as pH, EC, OC, Na, Cl, Ca, and Mg were evaluated. The results obtained from the soil chemical analysis parameters showed that the pH value decreased in all the treatments with effluent compared to the control, and this decrease was not significant in any treatment. The values of EC and Cl have increased in all plants, and these values were significant in the FR100 treatments with an increase of about 195 and 561% compared to the control, and in the FE100 treatment with an increase of about 54 and 162%, respectively, at the 5% probability level. The amount of OC in the FR100 treatment was significant with an increase of about 41% compared to the control treatment, but in other plants, this ratio was not significant in any treatment. The maximum amount of Mg in the FR50 treatment was 30.27, which has a significant effect compared to other treatments. The amount of Na and Ca in the FR100 treatment was significant with an increase of about 343% and 130%, respectively, compared to the control treatment, while in FE and DI plants, this ratio was not significant in any treatment.

As it has been for several years, drought conditions in various regions of Iran, including the central part of Marvdasht city in Fars province, have been very noticeable and have led to a severe decrease in the quantity and quality of groundwater, resulting in severe restrictions on agricultural production. Therefore, the farmers in the region have spontaneously turned to planting drought-resistant trees such as olives and pistachios. On the other hand, due to the significant reduction in the quantity and quality of groundwater in the study area, the quantitative and qualitative parameters of the fruit of the region's agricultural products, especially olive trees, which are irrigated under these conditions, are effective. It can be said that the quality parameters of olives increase with low irrigation and high salinity (to a tolerable extent). On the other hand, water and salinity stresses will have different effects on the performance of the mentioned plants. In this region, olives are used in two forms, canned and oil production. The amount of olive oil is often dependent on the growing conditions and fruit ripeness, and how the oil accumulates. The amount of oil in the dry matter of the fruit during the fruit ripening period (second fruit growth period) and its accumulation increases until the onset of dark purple. The quantity and quality of irrigation water affect the time and amount of oil accumulation, as well as the quality of olive oil. Also, the shelf life of olives in canned conditions and the shelf life of the aroma and taste of extra virgin olive oil are important features that will be controlled and examined by studying the density of olives during the fruit growth period. Therefore, the main purpose of this study is to investigate the changes in the density of olives during the fruit growth period under conditions of low irrigation and salinity stress.

The study area is located in the central part of Marvdasht city in Fars province, Iran, at geographical coordinates '693196;3303288' with an elevation of 1620 meters above sea level. According to the De Martonne method, the climate of the region is semi-arid and the dominant wind direction is eastern. Two years (2020-2021) of field experiments were conducted to study olive fruit density in a 20-year-old olive orchard (Roghani variety). The experiment utilized a factorial layout in a randomized complete blocks design with three replications. Five irrigation levels (I1-I5) were tested, ranging from 25% to 125% of olive water requirement. Three saline water levels (S1-S3) were also included, with S1 being saline well water with an electrical conductivity of 3.5-7.5 dS/m, S2 being a combination of 50% well water and fresh water, and S3 being fresh water. The weight and volume characteristics of olive fruits were examined and measured at seven different periods, starting from the fruit's appearance in June until its harvest in December for oil production. The I5S3 represented the control treatment.

Despite the fact that poor quality and quantity of irrigation water (S1, I1, and I2) will result in a decrease in the weight and volume of olive fruit, it is beneficial for improving the quality of suitable oil and will have an impact on the density of olive fruit. Oil production in olive fruit, which occurs during the second period of fruit growth, has a significant role in the density of the fruit. If the volume of fruit does not change (in the case of low-quality and low-quantity irrigation water), due to the increase in oil in a specific volume, it will lead to an increase in fruit weight and consequently an increase in olive density. The increase in density during the first growth period is accompanied by the production of dry matter in the fruit. A decreasing trend in the density of olive fruit can be observed in all irrigation treatments and different salinity levels in both consecutive years. The study found that normal irrigation water (I4 and I5) and appropriate quality (S2 and S3) increase the weight and volume of olive fruit and alter the density of olive fruit. The interaction effect of salinity and irrigation on the density of olive fruit was significant (5%) in both years. In 2020, changes in fruit density during the second period of fruit growth at salinity level (S1) were more pronounced in different irrigation treatments from I2 to I5 compared to other salinity levels (S2 and S3). The highest and lowest density values in 2020 were I2 and I3, respectively. The highest fruit density (1.1356 gr/cm3) was observed in the high salinity level (S1) and low irrigation treatment (I2). In 2021, the highest fruit density (1.1105 gr/cm3) in the first period of growth is related to S1, and in the second period of growth, it decreases compared to S2 and S3. In the same year, I1S3 had the highest value (1.0753 gr/cm3) and I5S3 had the lowest value (0.9899 gr/cm3) in the second stage of olive fruit growth. Although low quality and quantity of irrigation water (S1, I1 and I2) reduces the weight and volume of olive fruit, it is suitable for improving the quality of oil and will affect the density of olive fruit.

The factorial experiment based on a randomized complete block design was conducted with three replications at the research greenhouse of Tabriz University in 2017. The experimental factors include three levels of salinity stress (non-saline, salinity 3 and 6 dS/m) from the source of sodium chloride, foliar spraying in three levels without hormonal and nutritional foliar spraying, foliar spraying of 2 mM silicon and foliar spraying of 1mM salicylic acid, and the third factor, bacterial inoculation in four levels included: no inoculation, inoculation with Azosprilium, inoculation with Azotobacter and combined inoculation of two bacteria. The results of this research showed that the salt stress reduced the growth and yield of garlic. Spraying of salicylic acid and silicon and inoculation with bacteria improved potassium absorption, plant height, and leaf surface area, number of leaves per plant, yield components, biomass, and yield of garlic. The treatments significantly reduced the sodium concentration in both roots and leaves. The positive effects of the proposed treatments not only improved plant growth and performance under salinity stress conditions but also under non-saline conditions. Among the studied treatments, salicylic acid and silicon foliar applications along with the combined use of Azospirillium and Azotobacter showed more favorable effects on the growth and productivity of garlic than the other treatments. Finally, it was suggested to use growth-promoting bacteria in combination with salicylic acid and silicon solution spraying to mitigate the effects of salinity stress in garlic plants.

In this research, nine numbers of systems were built and urban water flow was established continuously from December 2019 to June 2014. All systems were planted in the soil with different densities of 10, 20, 30 and 40 cm. The selected hydraulic retention time was 5 days, and for each retention time, this experiment was repeated in three stages, for six months. The concentration of calcium, magnesium, potassium, chlorine, carbonate, bicarbonate and EC input to the systems and their output were measured and the concentration changes were compared using SAS statistical software. The comparison results of the average density of plant cultivation, changes in temperature, month, and their interaction in the efficiency of removing salinity parameters were observed to be significant at the 95% confidence level. Comparing the average effect of temperature on salinity removal showed a significant difference between the efficiency of salinity removal in some months of the year. The interaction effect showed that the highest salinity removal efficiency equal to 17.75% was obtained in the retention time of five days in the soil cultivation system and in July. According to the results, it can be said that the highest average for the EC parameter occurred in December at a density of 40 cm and the lowest average value for a density of 20 cm occurred in April.

Given the importance of water resources, especially groundwater resources, the application of appropriate management methods in quantitative and qualitative areas is well understood. The purpose of this study is to determine the most appropriate interpolation method to investigate the spatial and temporal changes in water quality in the Qaen plain aquifer. In the present study, in order to evaluate water quality, the values of 10 water quality parameters including: concentration of calcium, magnesium, sodium, chlorine, potassium, bicarbonate, sulfate, salinity, TDS and acidity ions, using IDW, LPI, GPI, OK and SK interpolation methods. It has been interpolated and researched in 2009 and 2017. The results of comparing 5 intermediate methods using RE and RMSE values showed that for most of the quality parameters studied, IDW method with the lowest error rate is the most suitable method for intermediation. It was also found that the highest error rate was related to the LPI intermediate method for the hco3 parameter with a value of 11.84 and the lowest error value was related to the IDW method for the EC and Cl parameters with a value of 0.01 . By comparing IDW zoning maps in 2009 and 2017, it was found that the concentration of most of the studied quality parameters has increased in the statistical period under study. The upward trend in Qaen aquifer in the northeastern part is more intense and the highest upward trend in this part of the aquifer is related to the concentration of calcium ions, chlorine and salinity.

In addition to the distribution of elements in the soil solid phase, element species in the solution are also very important due to their importance of providing elements for root uptake. For a deeper study of the chemical cycle of elements in saline soils treated with biochar, the study of speciation is very useful and provides a method to reduce or transform the toxicity caused by toxic elements in saline soils. Therefore, to investigate the effect of biochar on Cd speciation in two saline calcareous soils, 15 mg kg-1 Cd as cadmium chloride was added to the soil sample (200 g), and the soils were incubated for three weeks at 25±2 °C at 80% field capacity. After the incubation period, salinity levels of 20 and 40 mmol kg-1 as sodium chloride (equal to 3.65 and 7.30 dS m-1) were added to the soils. Then, the 1% (w/w) of the sugarcane bagasse and biochars produced at 400 and 600 °C were added to the soils, and then incubated for three months at 25±2 °C at 80% field capacity. At the end of the incubation period, for the speciation of Cd in the soil solution (in a 1 to 2 ratio), the concentration of dissolved cations and anions in the soil samples was measured. The results showed that the interaction between salinity, biochar, and soil on Cd2+, CdCl+, CdCl20, and Cd(SO4)22- was significant. The application of biochar in sandy soil reduced (p <0.05) the concentration of CdCl+, CdCl20, CdSO40, and CdOH+ species compared to the control soil, while it did not affect clay soil. Also, salinity caused by sodium chloride in sandy soil increased the concentration of CdCl+ and CdCl20 species and decreased CdSO40 and CdOH+ species compared to the control soil (p <0.05). The results showed that biochar in saline sandy soil was more effective than clay soil in reducing Cd toxicity.

In this study, the groundwater resources of Urmia Plain were evaluated for agricultural uses using a combined method that includes vulnerability, potential, and groundwater quality models. The vulnerability was evaluated by the DRASTIC method and the final map was classified into five classes with very high to very low vulnerability. The layers of NDVI, digital elevation model, drainage density, precipitation, and well density were considered as inputs of the potential model, and Analytical Hierarchy Process (AHP) was used to determine the weight of each layer. The potential map was also classified into five classes with very high to very low potential. The groundwater quality map was produced with three input layers including electrical conductivity (EC), sodium absorption ratio (SAR), and residual sodium carbonate (RSC) and weighting method. The combined map was produced by the maximum likelihood classification (MLC) method with five classes. The first and second zones with 40.31% of the area are suitable for agricultural uses, which include the northern, northwestern, and central semi-northern regions. The third zone with 22.90% of the area is in moderate condition and includes the central areas of the northern half and the southern half. The fourth and fifth zones with 36.79% of the area are in unsuitable conditions for agricultural use.

Groundwater salinization is a major environmental problem, especially in arid and semi-arid regions of the world. Different natural processes and anthropogenic activities can cause groundwater salinity. Factors such as rainfall, evaporation, groundwater pumping, agricultural and industrial activities, and artificial recharge of aquifers can affect the salinity of groundwater. One of the important factors that cause the salinity of freshwater aquifers is natural saline waters. Natural salinization of groundwater has occurred in many regions of the world. This phenomenon has been introduced as "dryland salinity". As a result of this phenomenon, salts accumulate in soil and water and affect human life and natural ecosystems. Several factors cause the natural salinity of groundwater in semi-arid regions. These factors include locally derived cyclic salts, salts in wind deposits, salts in marine deposits, salt domes, unsaturated zone salts and, salts resulting from rock weathering. Delineating the origin and mechanism of salinity is an important help in preventing the degradation of groundwater quality and optimal management of groundwater resources. In recent years, the phenomenon of salinization of groundwater has been observed in some areas of the Faryab plain in southeast Iran. This study aims to identify the origin and mechanism of groundwater salinity in Faryab plain aquifer.

This paper presents an integrated geophysical and hydrochemical investigation of the saline water intrusion into the Faryab plain. Geophysical studies were conducted by the geoelectrical method and include 55 electric soundings. The results of geoelectric studies have been analyzed using iso-resistivity maps and geoelectrical profiles. Twenty-seven water samples were also collected from abstraction wells to assess the quality of groundwater. These samples have been analyzed to determine the concentration of main cations and anions. The results obtained from the chemical analysis of water samples have also been examined and analyzed using spatial distribution maps of qualitative parameters, bivariate diagrams, and time series of water salinity. The mixing rate of saline and fresh groundwater has also been evaluated using ionic ratios of Na/Cl and Cl/HCO3.

The lowest electrical resistance was recorded in the central part of the plain. The specific resistance of the saturated zone decreases towards the center of the plain. Therefore, fresh water and saline water are hydraulically connected. According to the spatial variations of specific resistance, the Faryab plain is divided into two regions: one area with a resistance of more than 50 ohm-m and one region with a resistance of less than 10 ohm-m. The area with low specific resistance (less than 10 ohm-m) is observed in the center of the plain. The most important reasons for the existence of this area are the high groundwater level, the surface saline layers, and the salinity of groundwater. The electrical conductivity of groundwater reaches 64000 μmohs/cm in the center of the Faryab plain. The highest amount of sulfate and chloride ions are also observed in the water samples of this area. According to the Gibbs diagrams, the groundwater has been also influenced by the evaporation process.

In this study, the origin and mechanism of groundwater salinity in the Faryab plain in southeast Iran were investigated. Fine-grained sediments have been deposited in the central part of this plain. In the past, the underground water level in this area was a little far from the ground level and caused an evaporation zone of surface and underground water. As a result of water evaporation in the central part, evaporative sediments including chalk and salt sediments were formed and the amount of undergroundwater salts increased.Based on the results of geoelectrical studies, in the central areas of the plain, the amount of specific apparent resistance decreases, which indicates the presence of fine-grained sediments containing salt water in these areas. Investigating the quality characteristics of underground water also shows the occurrence of processes such as dissolution of halite, dissolution of gypsum and the occurrence of cation exchange process in the aquifer. Evaporation from underground water has also affected the water quality, especially in the middle part of the plain. As a result of high pumping from the production wells, the hydraulic load of the aquifer has decreased and the saline groundwater zone has expanded towards the production wells. Saltwater intrusion has caused salinity and quality degradation of underground water. According to the results of this research, the most important reason for the salinity of underground water in Faryab plain is excessive extraction of underground water and disturbing the natural balance of the aquifer. The most important solution to deal with the development of the salt water front in the Faryab plain is to reduce the exploitation of the aquifer, especially in its middle areas. It is also suggested to modify and improve existing artificial feeding facilities and locate new artificial feeding projects to control saltwater intrusion. Sampling from different depths of the aquifer and measuring minor ions such as iodine and bromine will greatly help to better understand the groundwater salinization process. Measurement of environmental isotopes such as oxygen-18, deuterium and chloride-36 will also help to enrich future studies. By preparing the mathematical model of the aquifer, the effect of different management measures on the salinity control of the aquifer can be investigated. By using the results of the mathematical model, the aquifer balance can be checked and the amount of underground water withdrawal can be determined.

In recent years, one of the most suitable options for saving water resources is the recycling of urban and industrial wastewater for irrigation which is common practice in different parts of the world, but if the use of wastewater Sewage can not be managed properly for irrigation, which may cause environmental problems. the purpose of this study was to investigate the effects of long-term irrigation with municipal treated wastewater (TWW) compared to well water (WEW) as a control treatment on soil chemical in three layer with three replications in a two-year split plot trial design was performed. in three It has been repeated. due to the availability of this source and the possibility of leaching, the risk of saltinification of this land has been somewhat overcome. the risk of sodiumization of this land has led to the fact that, due to the high clay content of this land, its future consequences include traps and reduced permeability. Irrigation with TWW resulted in a significant increase of 0.3 units of pH in irrigated soils with wastewater compared to WEW. The TN content varied between %11.30 and %25, which indicates the variable percentages of this parameter at the region of the study area. Also, the results of soil organic carbon (OC) changes as a result of irrigation with TWW showed that this irrigation effect was significant and increased by 55% for irrigation compared to treatments irrigation with WEW due to Organic contents in the wastewater.

In order to evaluate the efficiency of six different macroscopic water uptake functions, consisted of additive (M1), multiplicative (M2, M3 and M4) and conceptual (M5 and M6) models using field data of Ghods cultivar of wheat under salinity and drought stress, a study was conducted in the research field of university of Birjand during 2005-06 in split plots design based on randomized complete blocks (RCBD) with three replications. In this study, the main plots consisted of different levels of salinity (1.4, 4.5 and 9.6 ds m-1) and sub plots consisted of four levels of irrigation (50, 75, 100 and 120 percent of crop water requirement). The results showed that the additive model (M1) estimated yield less than actual amount. In other word, the effect of combined stresses on wheat yield was less than the one as compared to summation effects of salinity and water stress. The effect of drought stress on reduction of yield was more than salinity stress. The results also revealed that reduction functions of M6 and M5 models were better fitness to measured data than the other functions. The results revealed that M6 model estimated the reduction of relative yield of wheat under simultaneous stresses conditions of salinity and drought better than other models ( RMSD=0.17), although the M5 model also had acceptable accuracy (RMSD = 0.22).

The salinity of irrigation water resources combined with improper irrigation and drainage management is considered one of the most important threats to the sustainability of the agricultural sector in irrigated lands of the country. According to an overall estimate, about half of the country's irrigated farms have salinity problems at different levels. Given that no up-to-date and accurate report on the salinity status of agricultural water resources of Iran has been prepared so far, this paper decided to do this with the help of the latest statistics and information available at a national scale. For this purpose, the quality (salinity) data of agricultural water resources related to Iran Water Resources Management Company and also the results of previous studies on the quality of surface and underground water resources were used. The results of data analysis, which was conducted on 44.5 billion cubic meters of groundwater used in the agricultural sector, show that the average electrical conductivity of these resources is around 2.0 dS.meter-1. of which, about 31% (equivalent to 13.8 bcm), as well as about 20% of the surface agricultural water resources (equivalent to around 3.6 to 4.4 bcm) have salinities higher than the average. Concludingly, the possible effects of salinity on crop yield have also been provided, as well as proper solutions to overcome the salinity problems of irrigated agriculture.

Recent researches have proven the effect of salinity of water and soil resources on the bioavailability of cadmium.In this study, the effect of different sources of salinity including sodium chloride, sodium sulfate and calcium chloride on cadmium transport in two different soils was investigated.Soil columns with a height and inner diameter of 50 and 10 cm, respectively, were subjected to leaching of cadmium solution at a concentration of 100 mg/L along with various salts of sodium chloride, sodium sulfate and calcium chloride at a concentration of 100 me/L for 10 days. The drained solutions were analyzed at three depths of 3, 7 and 50 cm. The simulation of cadmium chemical species in the soil solution was performed using Visual MINTEQ 3.The presence of salinity along with cadmium solution caused more transport and drain of cadmium than the control soil. The highest cadmium concentration drained from the columns was belonged to the soils which received calcium chloride with the mean of 19.6 mg/L whereas the lowest was determined in soil received sodium sulfate with the mean of 6.1 mg/L. Due to the formation of chloro-cadmium complexes, treatments containing chloride had a more obvious effect on the transport of cadmium in the soil columns. The simulation of cadmium speciation in solution containing chloride showed that CdCl+ and CdCl2(aq) account for more than 80% of the cadmium species, while in those containing sodium sulfate, this dominant mainly included two species of Cd(SO4)2- 2 and Cd(SO4)(aq). Generally, salinity conditions affected by chloride ions in cadmium polluted lands can increase the potential of this toxic metal entering water sources and food chain.