mojtab khoshravesh

Nitrate is a major contaminant that is extensively found in water resources in many countries, leading to environmental problems. In this study, a batch system was used to study the removal of nitrate from aqueous solutions by micro and nanoparticles of beech leaves. After the preparation and modification of adsorbents, the effect of soluble pH, contact time, and dosage of adsorbent on nitrate adsorption were investigated. Kinetic and isotherm adsorption models were used to study the adsorption process. The results showed that the optimum pH and adsorbent dosage for nitrate removal by micro and nanoadsorbent of beech leaves were 3 and 10 g/L, respectively. Equilibrium time for micro and nanoadsorbent beech leaves was obtained 120 and 90 minutes, respectively. Among the kinetic models, Ho ̓s pseudo-second-order for the micro adsorbent and the Lagergren ̓s pseudo-first-order kinetic model for the nanoadsorbent had the best fit to the experimental data. According to the Langmuir model, the maximum adsorption capacity for nanoadsorbent beech leaves (16.69 mg/l) was higher than the micro adsorbent beech leaves (10.68 mg/l). The results showed that the nanoadsorbent of beech leaves are more capable for nitrate removal from aqueous solutions than the microadsorbrnt.

The lack of water for humans and the environment is one of the serious problems of today's world. Drinking water in Sari city and its dependent villages are provided with groundwater. The poor quality of the outlet water after the pressurized sand filters in the Moallemkola water treatment plant led to investigate the effective factors on the efficiency of the above filters. The pressurized sand filters substrate was composed of three types of silica granulation. This research investigated the physical and chemical parameters of pressurized sand filters by choosing the type of granulation and the use of a single layer and double layer in the pressurized sand filters bed (silica, silica-anthracite, and leca-anthracite), as well as changing their surface load in seven steps. Samples were taken in all steps and from five points in the water treatment plant (inlet water, after aeration, at the beginning of the filter operation, at the end of filter function and after chlorination). The results showed that the best option is the simultaneous use of silica and anthracite in the filter bed, employing 1.5 times of surface load in the water treatment plant, along with the use of aeration and sedimentation units. The removal efficiency of turbidity, TDS, TSS, calcium, magnesium and iron parameters was obtained 85.41, 23.54, 56.94, 21.08, 32.28 and 89.47%, respectively. Therefore, the use of double layer of silica and anthracite will increase the quality of water, and it is recommended for areas with high turbidity.

Climate warming causes prevention of the latest spring frosts and reduces the spring freeze risk during flowering. The purpose of this study was to explore the effect of climate change on the chilling requirement and the flowering date of completion of the phonological stages of different plants in Sari. A 45-year weather data (1970-1970) of Kiasar Synoptic Station were used with data access from National Centers for Environmental Prediction. The predetermined output of the large-scale climatic model (CanESM2) was used after the downscaling observation for RCP2.6 scenarios. Using the ChillR and Climdex model, the flowering date of DOY (day of year) and the Growing Season Length (GSL) were estimated. Mann-Whitney non-parametric test and Kendall's trend were used to compare the first half of the near future (2016-2055) and the second half of the distant future (2056-2100) with the present. The results showed although the growing season length increases, but a significant difference between the air temperature in the chilling and forcing phases is caused a significant change in the appearance of phenology stages of the deciduous fruit trees in the studied area. Over the past decades (1980-2000), about two weeks was added to the length of the growing season. However, the flowering date will take place three decades earlier than the past climate. These significant changes in cultivated climate parameters lead to irreparable phonological disorders in the coming periods.

One of the common problems in arid and semi-arid regions of the country is the presence of saline and sodic soils. Therefore, water and soil management is one of the key issues in supplying the food for growing population of the country. In this study, the effect of different treatments on chemical properties of the soil was investigated to reclaminate the saline and sodic soils in Azaranegin, Tabriz. Treatments included sulfuric acid, iron sulfate, sulfur and irrigation water as a control. Also, the amount of amendment materials was investigated. The amendment materials were added to the soil with the rate of 10% and 20%, separately. The results showed that the application of sulfuric acid reduced the amount of Exchangeable Sodium Percentage (ESP) and the Sodium Adsorption Ratio (SAR) to less than 60% and 45%, respectively. On the other hand, the results showed that the application of sulfuric acid and iron sulfate reduced the ESP, SAR and ECe values significantly. However, in the case of sulfur application, the mean parameters did not indicate any significant differences with control treatment. Finally, the findings showed that there was a significant difference between 10% and 20% levels of amendment materials, so that the most reduction of these parameters were related to the sulfuric acid with application of 20% level.

Due to the limited water resources, the deficit irrigation would be one of the most relevant methods in this situation. The purpose of this study was to optimize the water consumption and nitrogen level simultaneously. In this research, two different irrigation strategies of 75% (I2), 50% (I3) and 25% (I4) of water requirement and full irrigation (I1) and different nitrogen treatments with application of 150 (N1), 112.5 (N2) and 75 (N3) Kg/ha was investigated on yield production. Optimization of water and nitrogen showed that the proper yield function of soybean is the transcendental model among linear, Cobb-Douglas, quadratic and transcendental models. The optimum water and nitrogen levels of soybeans under water-nitrogen stress conditions was estimated 230 and 216.5 mm of water and 150 kg of nitrogen in two years. The results showed that the yield production was increased by 33.28% in N3 with deficit irrigation treatment (I2) as compared with full irrigation method.

In order to evaluate the effect of different amounts of natural and artificial soil modifiers on biological yield and grain yield of wheat, an experiment was conducted at the research farm of Kashmar high education institute. In this research, experimental treatments were included: four levels of A200 hydrogel (0(V0), 1(V1), 2 (V2) and 3 (V3) grams per kilogram of soil), four levels of vermicompost (0(V0), 2 (V1), 3 (V2) and 4 (V3) grams per kilogram of soil) and three levels of irrigation (40 (W1), 20 (W2) and 0 (W3) percentage of moisture loss). The experiment was carried out in a randomized completely block design in a factorial arrangement in a pot experiment in 144 pots. The results showed that the highest amount of biomass and grain yield in S3V3W3 treatment were 81.7 and 35 gram in the pot respectively, and the lowest biomass and grain yield were in S0V0W1 treatment of 35 and 10.2 gram in the pot respectively obtained. Application of A200 hydrogel and vermicompost had increased biological yield by 31.88% and 18.5% and grain yield by 23.5% and 20.25%, respectively. Under the conditions of this experiment, the interaction effect of A200 hydrogel and vermicompost compounds was not significant. The effect of A200 hydrogel and vermicompost on the grain yield was significant, as the highest value of grain yield was obtained in the treatment of 2 g/kg A200 hydrogel and 3 g/kg vermicompost and the highest value of biological yield was obtained in the treatment of 3 g/kg A200 hydrogel and 4 g/kg vermicompost. Separately use of A200 hydrogel and vermicompost is recommended for achieving maximum biological yield and grian yield.