Considering the limited water resources, optimum use of water is necessary. With the use of some materials such as superabsorbent polymers, irregular rainfall and other limited water resources can be used for preservation and storage of water in the soil. Superabsorbent hydrogels with absorption of water and fertilizer minerals and alternating expansion and contraction, improved the physical and chemical properties of soil. To evaluate the effect of superabsorbent polymer A200 on the Lettuce yield and its water productivity, In 2016-2017 this experiment was conducted in a completely randomized design factorial with two treatments of irrigation regime at three levels (60, 80 and 100 percent of crop water requirement) and four levels of superabsorbent hydrogel (0, 4, 6 and 8 g per kg of soil) in three replications in the research field of Faculty of Water Science Engineering, Shahid Chamran University of Ahvaz. The measured yield components included: fresh weight, fresh weight of leaves, dry weight of leaves and number of leaves. The results showed that the use of superabsorbent and deficit irrigation has a significant effect on yield and water use efficiency. The highest amount of yield components was observed in S3 treatment except for the number of lettuce leaves that the highest amount of which was measured in S4 treatment. Also, irrigation level on yield components of lettuce and water use efficiency at one percent level had a significant effect; reducing the available water for plant reduced the yield and highest value of yield component was obtained at I1 level and the lowest of them observed in level I3. The highest amount of water use efficiency was observed at level I4. The interaction of superabsorbent and deficit irrigation on yield components and water use efficiency was not significant, but the highest effect on yield components and crop growth was observed in I1S3 treatment as well as the highest water use efficiency in I3S4 treatment. Also, based on water balance in soil, the water requirement was 331 mm during the growth period.

In this study, a SIMulation of EvapoTranspiration of Applied Water (SIMETAW) model was evaluated for simulation of potential evapotranspiration and the effect of climate change on potential evapotranspiration in the future period (2040-2080). For this purpose, the daily data of four weather stations, Ahvaz, Rasht, Shahrekord and Sanandaj in the period of 1961-2001 were used. In the first step, the efficiency of SIMETAW model in simulation of daily weather variables were evaluated from the long-term average monthly, then, the simulated potential evapotranspiration with model were compared with the potential evapotranspiration calculated using observation data. The results showed a high ability of model for simulation of climate variables and the highest accuracy in simulation of maximum temperature (R2=0.9954) and precipitation (R2=0.3716) was related to the Mediterranean climate, minimum temperature (R2=0.9947) and dew point temperature (R2=0.9942) was related to the humid climate, wind speed (R2=0.8094) was related to the dry climate and Solar radiation (R2=0.9902) was related to the semi-arid climate. The highest accuracy of SIMETAW model in simulation of evapotranspiration was related to the Mediterranean climate (R2=0.9936), semi-arid climate (R2=0.9935), dry climate (R2=0.9903) and very wet climate (R2=0.9846), respectively. In the second step, sensitivity analysis of model was performed in the range of -30 to +30 percent. The results showed that the model has a moderate sensitivity to maximum temperature, solar radiation and wind speed and has a low sensitivity to dew point temperature and minimum temperature. In the third step, meteorological parameters were simulated in future period (2040-2080) under two emission scenarios (A2 and B2) HadCM3 (Hadley Centre Coupled Model, version 3) outputs and using downscaling model of SDSM) Statistical Downscaling Model (. Then downscaling meteorological parameters in the future period used as SIMETAW model input and potential evapotranspiration was simulated in the futue. In the fourth step, temporal trend of the potential evapotranspiration was evaluated using trend analysis Mann-Kendall and Sen's estimator on monthly basis. The results showed existence increasing trend for evapotranspiration in most months. Finally, the type of climate in the future period was studied. The results showed that the type of climate in Ahwaz, Rasht and Shahrekord stations does not change in the future period but in Sanandaj under both scenarios, type of climate in the future period change from Mediterranean to semi-arid.

In view of water crisis, effective prevention of water resources contamination is increasingly important. The presence of heavy metals in drinking water at concentration greater than acceptable limits may result in various adverse health effects. Therefore finding an effective method for removing heavy metals from water is very important. Adsorption process is one of the most efficient and application technology water and wastewater treatment in the world. Heretofore, valuable efforts is done to develop low-cost adsorbents using agricultural, industrial and urban waste.The purpose of this study, is to investigate modified Pine leaf adsorbent as a suitable and low-cost adsorbent for removeing copper ions from aqueous solutions. Pine leaf powder prepared were modified by three methods using NaCl, surfactants and NaCl with surfactant and the results of the tests were compared with each other. Characteristics of absorbent was determined using SEM and FTIR. To determine the factors effective absorption was used of the batch system. The effects of parameters copper concentration (1, 2, 5, 10, 15, 20 mg/L), pH (4, 5, 6, 7, 8), adsorbent dosage (0.5, 1, 2, 4, 5 gr) and contact time (5, 10, 20, 60, 90, 150 min) on the adsorption were investigated. Based on the results from the process of removal copper, the modified with NaCl is get greatest absorption efficiency and the best performance.The optimum conditions for the removal of copper was obtained at pH 7, concentration 5 mg/l, adsorbent dose 1 g and time 30 minutes. The maximum absorption capacity was obtained for each of the modified adsorbents with NaCl, surfactants and NaCl with surfactant respectively 4.073, 3.525 and 3.516 mg/g. Langmuir and Freundlich isotherm models were used to describe the adsorption isotherm. The equilibrium adsorption results are fitted better with Langmuir isotherm compared to Freundlich models for all the three methods modified. Adsorption kinetics were modeled using the Lagergren and Ho et al. models. The results indicate that the Lagergren model well-described copper absorption by the modified with NaCl and the Ho et al model copper absorption by two other absorbents. Overally, the results revealed that modified leaf pine tree can be an attractive option for copper removal from contaminated waters.