Regarding the problem of water scarcity and increasing demand for water and water supply problems and the high volume of Saline water sources along with fresh water resources, the management of salt and sweet water for agricultural production as a way to preserve water In conditions of water shortage. In this study was evaluated the effect of Partial Root-Zone Salinity Stress on the water uptake in silage corn in lysimeter in a greenhouse. The experiment with five treatments including: 1-No stress, control; Salinity stress in all root, 2-Mix, 3-Interval, Salinity stress in half of the root (despite the thin blade), 4-Fixed Partial Root-zone Salinity-stress, 5-Alternative Partial Root-zone Salinity-sress in three replications in a complete randomized design. The results showed that the cumulative uptake, root area and root volume were significant at 5% level. In the Mix treatment, the highest accumulation (333. 8 mm) and wet biomass (45. 7 t/ha) and lowest salinity stress coefficient (Ks=0. 89) were observed. In the Alternative Partial Root-zone Salinity-sress treatment, the lowest cumulative uptake (244. 0 mm) and wet and dry biomass (34. 9 and 11. 3 ton/ha) and the highest salinity stress coefficient (KS=0. 65) were observed. Due to the lack of water resources and the lowering of the quality of water in certain conditions, instead of drought stress, It is possible to use salinity stresses using Saline water sources (Drainage water produced in irrigation and drainage projects and projects) along with quality water sources.

Barley (Hordeum vulgare) known as a tolerant plant to salinity and has capability to produce reasonable yield under Saline conditions. Salinity decreases water uptake by seeds and can lead to delay in germination and seedling establishment. To investigate the effect of salinity on barley germination, three different experiments were carried out in completely randomized design through 13 treatments each with three replications. In these experiments, germination process was studied within three different media including NaCl+CaCl2 solution, natural Saline water and natural Saline soil. Studied variety was the spring variety, Tropy. The salinity levels in all experiments were consisted of control (0.005), 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25 and 27 dS.m-1. The germinated seeds were counted at designated time intervals and continued up to full germination or until the consecutive counting were the same. The number of germinated seeds as well as the germination rates were then calculated and analyzed. The results indicated that by increasing salinity, both percentage and rate of germination decreased. There were further reductions in natural Saline water than the NaCl+CaCl2  solution. In higher salinity levels, the germination rate was decreased, while the required time for germination has increased. Seeds were germinated in all salinity treatments within the NaCl+CaCl2 solution. But in the soil medium, germination was successful up to 13 dS.m-1 and the germinated seed numbers were rapidly reduced such that in 23 dS.m-1 treatment no seed was germinated. This observation can be attributed to the fact that in the Saline soil medium, the matric potential is also reducing the seed water uptake.

Using Saline water for irrigation of crops is a strategy for irrigation water management. In this study, the cyclic application of Saline and non-Saline water was investigated. Field experiments were carried out during a growing season in 2012 under drip irrigation for maize crop with nine treatments in randomized complete block design in Karaj. The treatments were based on alternative irrigation management of Saline and non-Saline water on three salinity levels of 0.4, 3.5 and 5.7 dS/m and freshwater application in every one, three and five Saline water application (1: 1, 3: 1 and 5: 1, respectively). The 1: 1 management was better than the other managements in terms of crop yield. The results showed that while the highest wet weight yield (56.2 t ha-1) was obtained in the F treatment (irrigation with non-Saline water constantly), but the highest irrigation water use efficiency based on wet weight (14.9 kg m-3) was acquired in the 3S1: 1F treatment (thrice Saline water (3.5 dS m-1) andonce non-Saline water, alternatively). Thus irrigation water use efficiency was increased in cyclic using of Saline and non-Saline water because of less water use in Saline irrigations, despite the relative reduction of crop yield. The results indicated that the percentage of crop yield decreased by 10.3 for every 1 dS m-1 increase in salinity level of irrigation water in fixed management. In this study, the crop yield in alternative management was higher than mixing management.

Total hardness (TH) of water causes numerous problems in life and industry, that shows the necessity of water hardness removal. In this research, different sorbents such as almond shell, wheat husk, rice husk, sawdust, zeolite, bentonite and activated carbon in raw state, acid-activated and alkaline-activated conditions for removing Ca, Mg and therefore, water hardness were used. The results of this study showed that some of sorbents needed to be activated by acid or base to remove calcium, magnesium and hardness of the brine solution in different salinities. In salinity of 20 dS m-1, acidic-activation of rice husk, sawdust, zeolites and activated carbon increased Mg removal from Saline water. In this salinity, alkaline-activation of almond shell and bentonite and likewise acidic activation of wheat and rice husk enhanced Ca removal from Saline water. Moreover, alkaline activation of almond shell and bentonite and likewise acidic activation of sawdust, wheat and rice husk caused reduction of Saline water hardness. Removal percentages of calcium, magnesium and hardness for salinity of 9 dS m-1 were greater than those for the salinity of 20 dS m-1.

In arid and semiarid regions of Iran most of the irrigation waters are Saline. These waters are used to grow strategic crops such as wheat and barley with acceptable yields. Because of the necessities of using Saline water in agriculture, research on plant tolerance to salinity has great importance. In this study, five Saline irrigation water treatments were used on sunflower (Zarya cultivar) in three replicates in RCBD. Three Saline water application treatments were 2.6, 6.1 and 10.5 dS/m (S1, S2 and S3) during all the season and two Saline water application treatments irrigated with 2.6 dS/m water in early season (germination and establishment stages) and, for the rest of growth period, Saline water of 6.1 (S4) or 10.5 dS/m (S5). The result shows that seed relative yield (Ry) in S2 and S3 were about 62 and 20 percent, respectively, compared with S1 treatment. Ry of S4 and S5 were 66.6 and 48 percent, respectively. To estimate the Ry, the best correlation was obtained with weighted average of irrigation water salinity (ECiw) in the season and was calculated from this equation (Ry=130-9.85 (ECiw)) with R2=0.67. According to the results, application of good water quality (ECiw=2.6 dS/m) (in rates of 20-25 percent of crop water consumption) during the germination and crop establishment and using water salinity of 10.5 dS/m for the rest of season had 28.4 percent yield increase compared to 10.5 dS/m (S3) in all the season. Mean electrical conductivity of soil saturation extract (ECe) during growth period and for the 40 cm soil depth were 8, 12.5, 19.4, 11.6 and 14.8 dS/m in S1 to S5, respectively. Also sodium absorption ratio (SAR) in the above mentioned treatments were 12.4, 21, 27, 20 and 25, respectively.

A field experiment was conducted using a completely randomized block design, in three replications with seven treatments in three replications for two successive growing seasons of corn crop. Treatments were comprised of: T1 and T2 (50% of T1): full and deficit irrigation with non-Saline water, respectively; T3 and T4: variable and fixed full irrigation with Saline-non Saline water in every other row, respectively; T5 and T6: fixed and variable deficit irrigation with non-Saline water in every other row, respectively and T7: full irrigation with Saline water. Irrigation water salinity for non-Saline vs. Saline treatments were 8 and 1.5 dS/m, respectively. The results showed that instead of deficit irrigation with non Saline water using alternate furrow irrigation, if not irrigated furrows are irrigated with Saline water, are more effective when they are compared with deficit irrigation. In deficit irrigation treatments 29 and 36 % and in T3 and T4 about 50 % of fresh water was saved in 2012 and 2013, respectively. The quantitative comparison have shown a significant reduction in maize yield by 22% with deficit irrigation scenarios (T2, T5 & T6) when compared with salinity treatments (T3 & T4). In terms of water use efficiency, the results indicate that if fresh and Saline water are of the same worth, deficit irrigation treatments have the highest water productivity and not significantly different from T1 treatment. However, water use efficiency is assessed as on the basis of fresh water, treatments T3 and T4 are of higher water use efficiency than the others and, therefore the criteria above have been selected as the preferred option. However, water use efficiency is evaluated as on the basis of fresh water, the efficiencies of water use in treatments T3 and T4 are higher than those in the others and therefore, they will be selected as the most acceptable options.

Irrigated lands of Khuzestan are lands with shallow and Saline groundwater, in which water losses of deep percolation during irrigation cause that irrigation water, because of the density difference, floats to the top of Saline aquifer creating a fresh and Saline water mixing zone. In new drainage issues such as reducing the depth of drain insertion aimed to an optimum use of water, dynamic studies on this region and evaluation of factors affecting its features are necessary. In the present study, two farms of sugarcane in south Khuzestan with two different drainage depths were selected. During the study, for each farm, installing pisometers at various depths and different distances from drain collector, the water level inside the pisometers and groundwater salinity were measured. Results indicated that by starting a heavy irrigation, hydraulic load is increased and hydraulic load variance between bottom layer (4 and 5 m) to the surface one (1 and 1.3 m) creates a vertical flow of Saline water. As well, by reducing the drain insertion depth and increasing the distance from drain collector, in addition of the increase of hydraulic load to 10-15 cm, mixing zone`s thickness increases to 1 m and the mean salinity line in this region reduces to 5-10 percent. But, as well, this region`s features depend on the depth of impermeable layer and existence of sand lenses, as with low depth of impermeable layer and existence of sand lenses, because of the hydraulic load`s lack of increase, mixing zone`s thickness, is reduced and the salinity is highly increased.

The objective of this study was to use the membrane distillation process for Saline water desalination using available commercial membranes and evaluate their performance in desalination. Direct contact membrane distillation with membrane of 0.014 m2 dimensions was used. Available commercial hydrophobic membrane with various pore sizes manufactured by different suppliers, were used. For all membranes, flux experiments were carried out at the same conditions. Results show that PTFE membranes with pore size of 0.45 and 1.0mm provides better performance. Also, the effect of support layer on flux and salt rejection surveyed. PTFE membrane with pore size of 0.45mm and scrim support had higher flux and salt rejection. Experiments showed that PTFE membrane with active layer thickness of 0.005 mm has higher flux and salt rejection. In all cases high salt rejection, more than 99% could be reached.