Iranian Water Research Journal

Abstract Introduction:

Onion, similar to most vegetables, is sensitive to inadequate irrigation. Onion has a shallow root and should be irrigated frequently with a small amount. Uniform and constant soil moisture during the growth period is very useful for onion growth. Excessive irrigation, in addition to reducing crop growth, increases costs, wastes water, reduces water productivity, and reduces product storability. Onion is one of the important agricultural products in Fars province. So far, little information has been published on the irrigation status and water productivity of onion fields. Knowing the amount of water required for irrigation and the water productivity of onion farms can help national and provincial planners and managers to increase production and save water more effectively. Therefore, the purpose of this research is to investigate the condition of onion farms in Fars province in terms of the amount of irrigation water and water productivity and the factors affecting them in agricultural conditions.



Methods:

Yield, irrigation water volume and water productivity were measured and studied in 30 farms in three major onion production regions Shiraz, Sepidan and Kazerun in Fars province. T-test was used for statistical comparison of the obtained results. Three studied areas and three types of surface, sprinkler and drip irrigation systems were considered as experimental treatments. The daily meteorological information needed to estimate the water requirement was obtained from the synoptic weather stations of the regions using the Penman-Monteith method. Three scenarios were considered to estimate the water requirement of onion. 1- Water demand from the Penman-Monteith method, using the meteorological data of the year of conducting the research (2020) 2- Water demand from the Penman-Monteith method, using the meteorological data of 10 years leading up to the time of the research, 3- Water demand from the National Water Document. The average efficiency of surface, rain and drip irrigation systems was considered to be 60, 75 and 90%, respectively, and the gross water requirement was calculated. The farm water flow rates were measured with suitable instruments. The amount of irrigation water per hectare of the field was obtained by multiplying the amount of field discharge by the total duration of irrigation during the growing season. Finally, by summarizing the results obtained from the difference in yield values, irrigation water and water productivity, suggestions were made to improve onion production and irrigation.



Results:

The average volume of onion irrigation water in the three regions Shiraz, Sepidan and Kazerun was 15848, 14888 and 10507 m3/ha, respectively. The average total volume of irrigation water was 13880 m3/ha. The difference in irrigation water volume between Shiraz and Sepidan was not statistically significant at 5% level. However, the difference between the volume of irrigation water in Kazerun region and the other two regions was more than 4000 m3/ha, which became significant at the level of 1%. By applying 118, 327 and 195 mm of effective rainfall for the three investigated regions, the average amount of applied water in the fields of the three regions was 17028, 18158 and 12457 m3/ha respectively. The average volume of applied water in the three investigated areas was 16054 m3/ha.

In terms of crop yield, the minimum, maximum, and average yield of the product in the three studied areas were about 34, 86, and 58 tons per hectare, respectively. The difference between Shiraz and Sepidan was less than one ton per hectare, which was not significant. However, the yield of Kazerun region was about 16 t/ha less than the yield of Sepidan and Shiraz regions, and these differences were significant at the level of 1%.

The productivity of irrigation water in selected onion fields varied from 2.12 to 8.51 kg/m3 and on average was 28.4 kg/m3. The highest and the lowest irrigation water productivity were in Kazerun and Shiraz, respectively. The highest and lowest total water productivity was obtained in Shiraz and Sepidan regions. The difference in irrigation water productivity in the studied areas was not significant at the level of 5%.

In Shiraz region, the amount of irrigation water given was 1003 and 723 m3/ha, respectively, less than the annual and long-term gross water requirements, and these differences were not significant at the 5% level. In Sepidan region, these differences were 1460 and 150 m3/ha, respectively, which was not statistically significant at the 5% level. In Kazerun region, the volume of irrigation water was 8427 and 7309 m3/ha, respectively, less than the gross water requirement, and these differences were significant at the 1% level. This means that the onion fields in this area did not receive the required water. In general, in the selected onion farms, the volume of irrigation water was less than the annual and long-term gross water requirement by 3419 and 2511 cubic meters per hectare, respectively, and these differences were significant at the 1% level.

Comparison of irrigation water volume with gross water requirement showed that drip irrigation systems were most in line with gross water requirement and on average 5% more irrigation was done. However, in the fields under sprinkler and surface irrigation, 17 and 45% of water was given less than the gross water requirement, respectively. Therefore, the yield in onion fields under surface irrigation was about 28% lower than the yield in fields under drip irrigation system. The difference in irrigation water productivity between drip and surface irrigation systems was not significant.

Abstract This study sets out to assess flood susceptibility in the Zoshk watershed, Razavi Khorasan, using the coupled fuzzy-AHP method, which incorporated different stages including rate assignment to criteria and sub-criteria based on expertise, fuzzification of rates, fuzzified weight assignment, and ultimately superimposing the layers. To this end, fifteen thematic maps of different characteristics were generated and used as inputs to the modeling process, including morphometric (DEM, slope, aspect, planar and profile curvatures, RSP, TRI), topo-hydrologic (flow accumulation, proximity to streams, HAND, TWI, SPI), edaphic (curve number), vegetation (NDVI), and climatic (precipitation) factors. Results revealed that among the adopted flood controlling factors, the factor of proximity to streams as the mainstream and a key driver to flood events plays the most critical role in the study area, followed by flow accumulation, curve number, and normalized difference vegetation index (NDVI) (topo-hydrologic, edaphic, and botanic, accordingly) with the respective fuzzified weights of 0.072, 0.071, 0.07, 0.068, and 0.067. The results of flood susceptibility zonation attest that 27.5% (1873 ha) of the entire study area falls within the very high and high susceptibility classes. The spatial distribution of high flood susceptibility classes in upstream and downstream sectors indicates that soft engineering techniques (biologic and biomechanical measures) in upstream and hard mechanical engineering measures in downstream areas should be concurrently considered. Additionally, educating the local communities about the concepts of flood hazard and risk should be considered across the entire area, from the lowest to the highest susceptible parts of the study area.

Abstract Introduction:

Recently, flood crisis due to the extreme rainfall events and climate changes are increased. There are several structural and non-structural methods for flood control and mitigation. The detention dams are structures used to attenuate the flood peak and reduce flood damages. The detention rockfill dams constructed by natural rockfill with porous media have interesting applicability for flood mitigation. The design approach for the detention rockfill dams include three main steps. 1- In the first step the location of the dam is done to regulate the reservoir volume required to decrees the flood peak with specified return period in such a way that provide the safe deplete flood condition in the downstream.; 2-In the second step the preliminary designs are done to design the detention rockfill dam and derive the preliminary dimensions and sizing the dam. 3-In the third stage the optimum dimension of the dam is determined using the preliminary designs done and single or multi objective optimizations. Based on these steps, there are several graphical or mathematical methods for preliminary designing of detention rockfill dams. The graphical methods are developed and used in early studies (Akan, 1990; McEnroe, 1992; Abet & Grigg, 1978; Wycoff & Singh, 1976). In these studies, the designs are done using single or double output pipes, without any infiltration form the dam body. In these studies, the depth-storage relation of dam is linear assumed while in the detention rockfill dams this relation is nonlinear. The graphical method of SCS uses two curves of peak storage ration to total flood volume and ration of peak flood discharge to beak inlet discharge. Also, in some studies simple design equations are developed.



Methods:

In this paper, using a simulator-optimizer model, the detention rockfill dam is optimized based on reliability. The case study of the paper is the design of detention rockfill dams for flood control in Karganroud river in the west of Gilan province based on hydrometry data 1957-2017, which can reduce the peak of flood based on preliminary design, single optimization, and reliability-based design optimization. The model is a multi-level model. The hydrological equation of nonlinear flood routing with non-Darcian flow inside the rockfills is used for preliminary designs. The structural stability analyses is used for the safety factor calculation and reliability determination. The optimization techniques is sued to derive the optimal design regarding the stability and reliability analysis. Using the governing equations, the dam can be simulated, and then the preliminary design can be gained for four different angles of the dam wall which are equal to 90, 80,75, and 70 degrees. Then these preliminary designs are redesigned to satisfy the reliability constraints in the optimization module. Based on the preliminary designs, the optimum design derived using Monte-Carlo simulation for uncertainty and Genetic Algorithm for multi objective self-adaptive optimization.



Results:

Based on the results, the stability criteria in preliminary designs are not satisfied based on the calculated SFS, SFO and SFF factors, so these dimensions are used as lowest limits in the optimal designs. The uncertainty analysis in the input parameters and the hydraulic performance of the dam under uncertainty is determined and reliable designs are selected. of the model is investigated using Monte-Carlo simulation The output results of the multi-objective algorithm have a wide range of different kinds of designs that can be made a decision based on them. The output results of single-objective and multi-objective optimization show that the optimal situation between four different situations occurred when the angle of the dam wall is equal to 80 degrees. The pareto front of costs versus reliability provide the final design of the dam regrading selected reliability. In this situation, the cost of construction is reduced by 20%. Also, the results confirmed that with reducing the angle of slopes, the construction cost reduced round 40%. The developed model in the current study by using uncertainty, optimization and reliability is capable in redesigning of detention rockfill dams in applied flood control plants.

Abstract The shape of the karst spring hydrograph is a direct reflection of all the physical processes that affect the flow of underground water inside the aquifer. Especially, the shape and process of the recession curve provides important information about the storage and hydrogeomorphological characteristics of the aquifer mass supplying the spring. In this research, a quantitative analysis of the hydrogeological behavior of Dimeh and Pirghar karst springs in Chaharmahal and Bakhtiari provinces located in the high and folded zones of Zagros during the common statistical period (from 2000 to 2019) have been quantitatively analyzed. This analysis includes classification of karst aquifer, modeling of hydrograph recession curve and estimation of water volume stored in saturated and unsaturated part of karst aquifer by Mangin method. . Estimation of the coefficients of recession components of fast flow (αf), transfer flow (αif) and base flow (αb) of springs based on the analysis of 18 recession curves obtained αf = 0.004، αif = 0.016 and αb = 0.042 for Dime spring and αf = 0.007، αif = 0.038 and αb = 0.125 for Pirghar spring revealed that the degree of development of Pirghar spring is 7 and Dime spring is 5.5;The analysis of the time series results shows that the discharge of Dimeh spring is under influence of majority of open, medium-sized fissure and with smaller influence of connected conduits, but the Pirghar spring hasa a system developed karstification of the aquifer, formed by large open tectonic faults and karstic channels. The high transfer flow rate of Pirghar spring shows the point charge and channel system of the karst region.

Abstract Achieving the spatial distribution of snow depth should be done through observation and on a compact scale. But due to practical limitations, it is difficult and sometimes impossible to collect information, especially in the mentioned scales. According to the existing problems, the use of machine learning approach and feature selection can increase the applicability of snow depth zoning in high areas. In this research, the effectiveness of reducing ineffective features in learning based on parametric and non-parametric models has been investigated. The samples used to test the hypotheses were taken from Chalgerd region of Iran. For this purpose, first, using the hypercube method, the location of 100 specific points and during a field operation, snow depth data were collected at the desired points and also at 195 other points randomly and with the federal model sampler. Then, using digital height model, 25 geomorphometric parameters were extracted and together with 6 bands of Landsat 8 satellite images and NDSI index were selected as model inputs. The results of this research showed that the parametric and non-parametric methods did not have acceptable accuracy in modeling the snow depth, but the linear regression model with the forward greedy feature selection method and the particle population optimizer with the mean squared error equal to 22.17 and 22.19 were able to Model snow depth changes with better accuracy.

Abstract Heavy metals are one of the most important causes of environmental pollution in the world due to the industrialization of societies. Wastewater production is one of the problems of waste accumulation in waste collection sites. Urban wastewater contains almost all known chemical elements and persistent pollutants in the environment such as heavy metals that are not biodegradable. Due to the ability of heavy metals to accumulate and cause toxicity in living organisms, this type of pollution is considered a serious and fundamental problem. Some heavy metals such as lead, cobalt and cadmium can be distinguished from other pollutants, because not only are they not biodegradable, but they can accumulate in the structure of living organisms and cause various diseases, even in high concentrations. be very low The use of plants as an effective and cost-effective technology to remove metal pollutants from contaminated soils and waters has been recommended as a new environmentally friendly method instead of other costly measures.

The purpose of this research was to investigate the absorption of some heavy metals in urban wastewater by vetiver and canna plants and its effect on some physiological and anatomical characteristics, as well as to evaluate the resistance of vetiver and oleander plants against heavy metals in urban wastewater. For this purpose, an experiment was conducted in the form of a randomized complete design with three replications using vetiver and canna plants. The plants at the same size and the same weight including vetiver plant and the rhizomes of canna plants were obtained from their cultivation places in Guilan province and placed in the pots at the end of the winter season that is, in the month of March, containing 10 kg of sifted soil. The control pots were irrigated with 500 ml of urban water and the treated pots with 500 ml of urban wastewater twice a week, and this process of watering the control pots and the treatment continued for 6 months. In addition, 3 pots containing 10 kg of sifted soil without plants were also irrigated with urban wastewater during 6 months, like the treated samples.

After 6 months, the amount of heavy metals in different organs of vetiver and canna plants was evaluated and the anatomical structure of the roots of vetiver and canna plants treated with urban wastewater was compared to the control plants. Also, the amount of lipid peroxidation of the cell membrane, the amount of proline and soluble sugars in the leaves of the plants treated with urban wastewater were measured in comparison with the control plants.

The results of investigating the effect of 6 months of irrigation with urban wastewater and urban water on the amount of zinc metal accumulation in the roots, stems and leaves of vetiver and canna plants showed that the amount of zinc was more than the standard level (200 mg/kg). The transfer factor (TF) for zinc element (Zn) was calculated as 0.72, which indicated the accumulation of zinc element in vetiver roots under treatment. Despite the high absorption of about 150 mg/kg zinc by treated plants, a significant amount of zinc element was observed in the final soil, which indicated the high contamination of urban wastewater with zinc element. The bioaccumulation of zinc element in the present research was 2.45 and this shows that vetiver plant is a good plant accumulator for zinc element in the root. In addition, the highest concentration of zinc element was found in the root of canna plant.

The results of investigating the effect of 6 months of irrigation with urban wastewater and city water on the amount of chromium metal accumulation in the roots, stems and leaves of vetiver and canna plants showed that the bioaccumulation rate of chromium in the treated canna plant was 4.43 and can indicate this the issue is that canna is a good absorber for chromium. The transfer factor (TF), which is the ratio of chromium metal concentration in the dry weight of shoot to root, was 1.64 for canna plant. This amount shows that the transfer of chromium to the aerial organs happened more, although the chromium element was also significantly accumulated in the roots.

The results of investigating the effect of 6 months of irrigation with urban wastewater on the root anatomy of canna and vetiver plants showed that the diameter of the root and the diameter of the central cylinder in the treated plants were reduced compared to the control plants, as well as the number of vascular vessels in the treated plants compared to the control. Heavy metals have different effects on the anatomy of plant roots, and the absorption and accumulation of metals in high concentrations has led to structural changes in the roots of various plants.

According to the investigation, the stress of cadmium and copper caused a decrease in the thickness of the mentioned parenchyma. According to the acidification of the soil after six months of irrigation with urban wastewater and the standard limit set for zinc metal, it was observed that zinc metal in the pure soil (soil without plants that was irrigated with urban wastewater with each irrigation period) was higher than the standard level. The effect of 6 months of irrigation with urban wastewater on the amount of malondialdehyde, proline and soluble sugar in leaves of vetiver and canna showed that the plants that were treated with urban wastewater had higher levels of malondialdehyde in their leaves than the control plants, so that high concentrations of zinc and cadmium led to an increase in lipid peroxidation in treated plants.

Based on the results of this research, 6 months of watering vetiver plant with urban wastewater containing heavy elements of zinc and chromium, a high accumulation of zinc was observed in vetiver plant, which shows that vetiver plant is a good absorber for zinc. In the canna plants treated with urban wastewater contaminated with heavy elements of zinc and chromium, high accumulation of zinc was also observed in the canna plants, which shows that the canna plant is also a good absorber for zinc, but since the large amount of these elements for these plants are stress-producing, the evidence of physiological and anatomical stress was observed in the treated plants. The highest level of urban wastewater pollution used in this research was attributed to the zinc element, and according to the bioaccumulation factor and the results of this research, canna and the vetiver plants are good absorbers for zinc and chromium elements. In such a way that both elements zinc and chromium were mostly accumulated in the roots of canna, but the investigation of the transfer factor showed that zinc and chromium elements were more transferred to the aerial parts of the canna plant and so the canna plant has the ability to absorb these two metals through plant extraction, and the vetiver plant, which did not show significant transfer in the aerial parts of the plant, showed the ability to absorb these two metals through plant stabilization. Therefore, it is recommended to plant the studied plants in soil polluted by urban water to refine the soil.

Abstract Introduction:

In recent decades, the widespread use of chemical fertilizers, pesticides, and urban and industrial wastewater for irrigation has caused growing concern about heavy metals pollution in the environment and agricultural soils. Soil pollution with heavy metals and moisture stress are the main threats to food security in the world. Drought stress is considered one of the most severe abiotic threats to the food security of the world, and management methods to conserve irrigation water, such as deficit irrigation, are being developed and are among the solutions to improve the efficiency of water consumption. Tomato is one of the most popular agricultural products in the world due to its high nutritional value, as well as being a source of antioxidants, fiber, vitamins, potassium, phenolic compounds, lycopene, and beta-carotene. Given its high water requirement, it is necessary to use strategies in arid and semi-arid regions of the world to compensate for water scarcity and the resulting drought stress without reducing yield. Biochar, as an organic soil amendment, can be effective to reduce the effects of water deficiency and change the activity of plant enzymes grown in an environment contaminated with heavy metals, especially cadmium. The aim of this study was to investigate the effect of rice husk biochar and deficit irrigation on matric potential and biochemical characteristics of tomato plants in soil contaminated with cadmium.



Methods:

The soil sample was collected at a depth of 30 cm from the Faculty farm. Rice husk was used to prepare Biochar. To produce biochar, oven-dried remains of the rice husk were placed in an electric furnace at a temperature of 400°C for 4 hours with a temperature increase rate of 5°C per minute. This research was performed in a factorial-based experiment in a randomized complete block design using three levels of rice husk (0 (B0), 3 (B3), and 6 (B6) ton/ha) and seven irrigation levels (50 (L50), 60 (L60), 70 (L70), 80 (L80), 90 (L90), 100 (L100), and 110 (L110) percent) with four replications in cadmium-contaminated soil with a total of 21 treatments in 84 pots. Tomato seedlings (Hirad variety) were cultivated in the greenhouse, and after 21 days, the seedlings were transplanted to the main pots. After mixing soil and biochar and adding the mixture to the pots, the pots were fully saturated. Soil moisture was adjusted at the field capacity level, then two tomato seedlings, 10 cm tall in the aerial part, were planted in each. In order to prevent nutritional stress, the amounts of required nutrient elements of nitrogen, phosphorus, and potassium were calculated based on the soil test results, and 500, 150, and 200 kg per hectare of urea, triple superphosphate, and potassium sulfate were added, respectively, to the soil of the pots before transplanting tomato seedlings. The application of different irrigation levels started three weeks after transplanting the seedlings to the main pots, after ensuring the complete establishment of the plants; it continued once every three days for 120 days until the end of the growth period. Then, the results of rice husk biochar application and different levels of water application on soil matric potential, biochemical characteristics and water use efficiency of tomato plants in cadmium contaminated soil were investigated. The data were analyzed using version 9.2 of SAS, and the graphs were drawn in Excel. Duncan's test was used to compare means, and the significance level was set at 0.05.



Results:

Studying the matric potential of the soil under the influence of biochar treatments showed that the matric potential increases FC, PWP and PAWC with the increase of biochar application in the B6 treatment. The moisture content of treatment B6 increased by 28.50% and 123.48%, respectively, compared to B3 and B0 in PAWC. The results showed that the Cd concentration absorbable to soil decreased with increasing irrigation and biochars application. The lowest cadmium concentration was observed in the B6 treatment at the irrigation level of 110 %. However, soil available cadmium values in the L90B6, L100B6, and L110B6 treatments were not significantly different. According to the results, the amount of cadmium in treatment B6 in L90, L100, and L110 decreased by 24.3%, 27.9%, and 34.2%, respectively, compared to treatment B6 in L50. Ion exchange can be one of the reasons for the stabilization of heavy metals in the soil due to biochar application. In addition, properties of soluble solids and vitamin C of tomato fruit increased significantly by reducing irrigation levels and increasing of biochar application. So, the properties of soluble solids and vitamin C of tomato fruit were 68.9% and 65.3% higher in L50B6 treatment compared to L110B0 treatment, respectively. On the other hand, catalase enzyme activity decreased significantly with increasing irrigation levels and biochar application. The catalase enzyme increase in L50B0 treatment compared to L110B6 treatment reached its maximum and was 1.2 times. The highest values of total chlorophyll and carotenoid were obtained in L110B6 treatment, which were 29.4% and 93.8% higher than L110B0, respectively. The best water use efficiency was observed in L90B6 and L100B6 treatments with 65.23 and 63.14 kg/m3, respectively, and the difference between them was not significant. Although the duration of the research was short and the experiments were conducted immediately after the end of the tomato growing season (after 4 months), but the biochar obtained from rice husk improved the physical conditions of the soil. Indeed, by reducing soil cadmium toxicity, biochar, especially in the B6 treatment, made the plant immune to cadmium stress. The B6 treatment at the irrigation level of 90% (L90B6) was recognized as the best treatment in terms of optimal maintain soil moisture, minimum cadmium concentration in the soil, and minimum water consumption during stages of the plant growth. Therefore, biochar application can be an economic solution to improve soil water retention, plant biochemical characteristics, and water use efficiency under water stress conditions in arid and semi-arid regions and soil cadmium contamination.

Abstract Introduction

In many countries of the world, water shortage has become a serious and worrying issue. Studies show that the agriculture sector is the largest consumer of water resources in the world. Therefore, scarce of water resources is considered the biggest challenge of agricultural development and ultimately food security. Rice is the largest consumer of fresh water worldwide and in terms of importance, it is the second most important edible grain after wheat which constitutes the food of two-thirds of the world's population. Therefore, need to increase productivity to feed the growing population by using efficient water management practices and water saving technologies, water saving technologies. Due to the decrease in rainfall in Mazandaran province, The area of rice cultivation and its production has decreased. These conditions can cause irreparable damage to the large production of rice in the province and the subsistence economy of the rice farmers will suffer irreparable damage. For this reason, rice production in Mazandaran Province, which is very important strategically and economically, it is necessary to change irrigation management and traditional cultivation method to reduce the water demand for rice production.

Methods:

The experiment was conducted in the form of a complete block-design with three replications and four treatments using, during the 2020 crop year in the Rice Research Institute of Iran-Amol. The selected rice variety was Tarem Hashemi. Treatments included conventional planting with periodic irrigation (T1), conventional planting with flood irrigation (T2), transplanting in un-puddled bed with flood irrigation (T4) and direct seed cultivation in dry bed with flood irrigation (T4). The number of experimental plots was 12 and the area of each was 30 square meters. Based on soil decomposition test and according to soil experts, Three types of phosphorus, potassium and nitrogen fertilizers were were used to all treatments. In two treatments, T1 and T2, the land was prepared with puddling, and in two treatments, T3 and T4, the field was plowed dry. Transplanting in puddled and un-puddled bed as transplants and in direct cultivation was germinated as seeds. In flood irrigation treatments, water flowed on the soil surface and The entire surface of the earth was flooded with a layer of water 5 cm high (with a 5-day irrigation cycle). In periodic irrigation treatments, after flooding the land, Irrigation was stopped and and after the water disappeared from the soil surface and after observing the first spot on the field surface, irrigation was done again (irrigation cycle 6-8 day). In this experiment, The exact volume of irrigation water was measured by installing volumetric meters in each of the experimental plots. Irrigation water productivity was calculated as the amount of yield produced per unit of irrigation water. Finally, variance analysis of the obtained data was done using SAS software and the mean of the treatments were compared through the least significant difference (LSD) test at the level of five and one percent.

Results:

The results showed that the cultivation method was effective on yield, plant height, water consumption and irrigation water, water productivity and water use efficiency and was statistically significant at 1% level of probablity. The highest and lowest yields belonged to T2 and T4 treatments with 4079.2 and 2941.7 kg/ha, respectively. The highest and lowest irrigation water belonged to T4 and T1 treatments with 10301 and 6537 m3/ha, respectively. The highest and lowest irrigation water productivity belonged to T1 and T4 with 0.61 and 0.29 kg/m3, respectively. Based on the results of this experiment, The treatment of conventional planting with periodic irrigation (T1) did not have a significant reduction in yield compared to The treatment of conventional planting with flood irrigation (T2). The treatment of conventional planting with periodic irrigation (T1) saved irrigation water by 17% compared to the common cultivation treatment with flood irrigation (T2) and increased irrigation water productivity by 17% .Finally, the results of this research showed that there is no need to flood crete during the rice growth period. conventional planting system with periodic irrigation (T1) was chosen as the superior treatment and it can be a suitable alternative to the common cultivation system with flood irrigation of rice and a suitable option to deal with water shortages in recent years.

Abstract Introduction:

Heavy metals (such as Cadmium, Cd) are one of the main pollutants in the environment, and their toxicities has caused concern due to their adverse effects on public health. Cd is a mineral pollutant for soil and a toxic element for plants and has negative effects on plant growth and yield which anthropogenic activities including farming, manufacturing, transporting etc. cause Cd accumulation in the environment. In order to control the entry of these pollutants into the food chains and also to improve the growth and yield of plants under pollution conditions, different management methods are used. One of the new methods is using of magnetized water in order to increase the plant's resistance to the pollution condition and also to control the uptake of this pollutant into plant tissues. Previous studies have solely reported on the phytoextraction and Phyto stabilization effects of heavy metals uptake in Vetiver grass. Also, magnetized water has been studied by researchers however, to date, there has been little studies about the effects of magnetized water on efficiency of phytoremediation and biochemical responses of plants. Therefore, the objective of this study was to investigate the effects of magnetized water on biochemical responses of vetiver plant and its phytoremediation efficiency under Cd pollution conditions.



Methods:

In order to study the effect of magnetic field on Cadmium (Cd) removal by vetiver grass (Vetiver Zizanioides), a study was conducted in the central nursery of Green Area and Parks Organization Bandar Abbas Municipality, Bandar Abbas, Iran, from March 20, 2020 to February 18, 2021. This pot experiment was conducted as a factorial arrangement based on a completely randomized design with three replications. The studied soil was sampled (surface layer, 0-30 cm) from an agricultural soil where located in Baghu village, Bandar Abbas, Iran, and after air-drying, it was sieved (2 mm) to measure some important physical and chemical properties. The studied factors were Cd in 4 levels (0, 0.5, 1, and 2 mg L-1) and irrigation water in 3 levels (magnetized water, semi-magnetized water, and non-magnetized water). At the end of the experiment, the concentration of Cd in root and shoot of vetiver grass, translocation and bioaccumulation factors and some growth and antioxidants of the plant including activity of Superoxide Dismutase (SOD), Catalase (CAT), and Peroxidase (POD), phenol, flavonoid and anthocyanin was measured. Some phytoremediation indexes including translocation factor (TF), bioaccumulation factor (BF), and uptake index of Pb in root and shoot (UI) were calculated were measured. Finally, in order to statistical analysis of the data, SAS 9.1 software was used, and in order to compare the means, Duncan's multiple-range test (DMRT) (P<0.05) was used and graphs were drawn using Excel software.



Results:

The results of variance analysis showed that the use of different levels of magnetized water and Cd pollution significantly affected the accumulation of Cd in roots and shoots, the bioaccumulation index (BF) and the translocation factor (TF) of Cd from the roots to the shoots. Also, the interaction effects of irrigation water and Cd concentration on them was significant (P<0.05). Biomass production, activity of antioxidant enzymes and non-enzymatic antioxidants of vetiver plant were significantly affected by the applied treatments, as well. The interaction effect of the studied treatments was also significant except for the activity of superoxide dismutase (SOD), anthocyanin and plant dry weight (P<0.05). Based on the results of means comparison, the highest concentration of Cd in roots and shoots, T), and BF were allocated to the magnetized water treatment, and by changing the concentration of Cd, the effect of magnetized water on plant responses changed, as well. The activity of enzymatic and non-enzymatic antioxidants also increased with increasing the concentration of Cd, but the treatment of magnetized water was a superior treatment. In general, the results obtained from this study showed that the use of magnetized water can be useful for increasing the resistance of plants to the stress of Cd pollution. Vetiver plant, in the conditions of facing with increasing the concentration of Cd pollution, initiates growth and antioxidant responses, which antioxidant responses are actually a defense mechanism of plants to deal with adverse environmental effects. On the other hand, the use of magnetized water technique in irrigating plants under Cd pollution conditions can have a significant effect on the type of plant responses and help the plant to withstand environmental stress (here Cd pollution). The use of magnetized water had a significant effect on the bioaccumulation index and the transfer factor of cadmium from the roots to the shoots. Nevertheless, to confirm the results obtained from this research, it is suggested to conduct more studies on higher levels of pollution, other heavy metals and different plants.

Abstract Water resource pollution with heavy metals is one of the most environmental problems at the global level. Removal of Pb (II) and Cd (II) ions from contaminated water is essential due to their high toxicity and tendency to accumulate in living organisms. Today, nanomaterials such as multi-wall carbon nanotubes (MWCNTs) have wide environmental applications due to their high surface area, small size, and chemical stability. In this context, the performance of MWCNTs was evaluated by removing Pb (II) and Cd (II) ions in a batch mode experiment. To study the adsorption process, the influence of different adsorption parameters, such as contact time, temperature, initial concentration of pollutant, the dosage of adsorbent, and pH values of the solutions were investigated. The experimental data were fitted to the pseudo-first-order and pseudo-second-order to analyze the kinetics adsorption studies of metal ions. Also, to determine the isotherm studies of metal ions, the Freundlich, Langmuir, and Langmuir–Freundlich models were used. The MWCNTs were characterized by several techniques including BET, FT-IR spectroscopy, scanning electron microscopy, and zeta potential. The results showed that the maximum metal adsorption occurred at pH, 6-8, contact time of 5 minutes, and adsorbent dosage of 0.05 gram. The pseudo-second-order type model satisfactorily (R2= 1) described the experimental metal data. Also, comparing the adsorption isotherm equations showed that the Freundlich-Langmuir model [(R2=0.984, SEE=4.42) for Pb (II) ions and (R2=0.969, SEE=5.27) for Cd (II)] was more proper in describing adsorption process. The maximum adsorption capacities of Pb (II) and Cd (II) ions were obtained at 137.86 and 110.82 mg g-1, respectively. The results obtained from the FTIR technique confirmed that the O–H groups on the MWCNTs surface have an essential role in metals adsorption.