جستجوی مقالات مرتبط با کلیدواژه « non-conventional water » در نشریات گروه « آب و خاک »

One of the ways out of the water crisis is to use polluted and non-conventional water. In this regard, a study was conducted in 2017 and 2018 in the Agricultural and Natural Resources College, the University of Tehran in the form of a completely randomized factorial design with four treatments, three replications, and a total of 12 experimental plots in the lysimeter environment. Experimental treatments included surface irrigation with contaminated water by heavy metals (SRC), surface irrigation with conventional water or control treatment (SRF), subirrigation with contaminated water by heavy metals (SBC), and subirrigation with conventional water (SBF). The texture of the soil inside the lysimeters was sandy loam, its pH was 7.4, and the heavy metals used were copper, zinc, and lead. The results showed that the highest copper concentration in SBC treatment was observed at a depth of 75 cm, which was 43% less than the maximum amount in SRC treatment, and 25 cm depth, which was significant at the level of 5%. Also, there was a difference between the maximum amount of soil zinc on SRC and SBC treatment of more than 4.2 mg/kg, and in subirrigation, 32% less zinc was absorbed into the soil, which was significant at the level of 5%. The average amount of copper uptake by the plant in SRC treatment was 4.97 mg/kg, which was 80% and 70% increase in copper uptake, respectively, compared to control and SBC treatment, and this difference was significant at the level of 1%. In general, top-down motion (SRC) is higher than bottom-up motion (SBC), indicating the use of heavy metal contaminated water in subirrigation.

To assess the role of non-conventional water in arid regions, an Operational toolbox was designed comprising an integrated allocation model and a decision support module. The Water Evaluation And Planning System (WEAP) was used to define and calibrate the existing conditions. Possible scenarios for water supply (including conventional and non-conventional water) and consumptions (including drinking, agriculture and industry) where examined under current and potential future scenarios. A multiple attribute decision-making tool was utilised to rank various scenarios. The toolbox was used in an arid catchment of Iran, where indiscriminate use of conventional water resources, has posed a dominating water shortage.The results of the various scenarios showed that there is no scope to increase in agriculture allocation while the industrial allocation may be increased provided the non-conventional water is utilised to a certain extent. The results obtained from the toolbox has indicated that water transfer from other catchments is not an attractive option compared to the use of non-conventional water The results imply the effective role of recycling for the industrial water allocation, and desalination for the drinking water supply management.

Due to the important role of irrigation water chemical composition in the yield of crops and its effects on the soil structure, it has been taken into consideration by the agricultural sector planners. In this regard, the sour and burning taste of water in some agricultural wells around the HamehKasi village in Hamedan province has caused concerns about their water composition and possible detrimental effects on soil stucture and plant growth. Therefore, the present study was conducted to evaluate the water quality and the trend of changes in its composition. In this study, 6 gaseous water-wells were identified and their salinity was measured 15 times in three years (5 times each year), and the trend of their electrical conductivity changes was evaluated by SPSS software. Also, from each well, one sample was taken in order to determine the electrical conductivity, cations and anions content, and their chemical indices were calculated and evaluated by means of different criteria and diagrams. The results showed that calcium and bicarbonate ions have the highest concentrations in these waters, and the water of the mentioned wells was considered as unconventional and was Ca-Mg-HCO3 type. The water salinity of these wells was high (from 2.96 to 6.07 dS/m), and had very high salinity and sodicity (C4S4) after correction of the sodium adsorption ratio. Due to high salinity of water, fine-textured soil and lack of sufficient water for leaching, it is expected that the soil will be salinized in the root zone by irrigation, and as a result, the yield of plants and especially perennial plants would decrease. However, the statistical analysis of the electric conductivity changes of gaseous water-wells in HamehKasi area indicated that the salinity of their water decreased significantly over time. Consequently, the quality of water in the HamehKasi area in terms of irrigation improved over time.

Water scarcity is an important challenge worldwide, especially in arid and semi-arid regions. Water-scarce countries will have to rely more on the use of non-conventional water resources to partly alleviate water scarcity. The reuse of wastewater for irrigation is considered to be beneficial for crop production, and due to its nitrogen and phosphorus content, it can help to reduce the requirements for commercial fertilizers. However, under certain conditions, this type of water if not well managed, can have negative impacts on cultivated crops and soils, particularly on soil salinity and sodicity, and may pollute groundwater, as a result of high nitrogen concentration of most treated wastewater. Besides nitrogen (N) contamination of surface and ground waters has become a serious and global environmental problem. The risk of groundwater contamination by N depends largely on the N input to agricultural fields in the form of inorganic fertilizers and on its effective use of agricultural crops. Improvement of irrigation and nitrogen application management during the growing period can be achieved using mathematical models. The goal of this study was to assess the effects of irrigation with raw and treated wastewater by using the HYDRUS-1D model for simulation of water and nitrate transport in a maize field.
The experimental station of the College of Agriculture and Natural Resources, University of Tehran, was considered as a case study. The information of maize growing season in 2010, as well as raw and treated wastewater of Ekbatan housing complex was considered as a source of irrigation water for simulation of water and nutrient movements in the soil by HYDRUS-1D software package. HYDRUS-1D numerically solved the Richards equation for describing the variably-saturated water flow in a radially symmetric domain and the convection-dispersion equation for solute transport. The soil hydraulic properties were described using the van Genuchten-Mualem model. Since the direct measurement of soil hydraulic parameters in the field or laboratory is time consuming and costly, they were estimated using the ROSETTA model, using particle size and bulk density data determined on soil samples taken from depths of 0-20, 20-40, 40-60 cm.
The results showed that water contents increased after any irrigation event, and then decreased gradually during the following hours and days, until the next irrigation took place. Deeper depths showed smaller water content variations since root water uptake and soil evaporation were more pronounced at shallower depths. Simulated plant water uptake was estimated to be 80% of the water application, indicating the high irrigation efficiency of the system. Cumulative deep percolation (DP) values increased rapidly at around 43 days after planting. This is obtained due to higher irrigation water depth applied at irrigation events after this time because of rapid growth of maize crop that is occurring due to increase air temperature at this time. Simulated deep percolation reached 6.98 cm which is 13% of the total amount of water applied during the growing season. Simulation results showed that N leaching at 60 cm depth for about 7.61 and 2.64 kg N ha-1 for raw and treated wastewater, respectively. Nitrogen concentration for raw and treated wastewater decreased due to root nutrient uptake. The results also showed that the crop N uptake was 76.2% and 81.9% of total N input (TNI) during the growing season, while 19.4% and 14.5% of TNI was retained in the soil at the end of the season for raw and treated wastewater, respectively.
The HYDRUS-1D model was used to simulate the transport of N-NO3- under the raw and treated wastewater application in the soil. Simulation results provided detailed moisture and N regime, as well as bottom boundary flux for percolation and N leaching estimation. N leaching is closely correlated with vertical water flow. The N leaching distributions at the bottom of the soil profile (60 cm) are similar to the corresponding water flux distributions. The results also showed that the crop N uptake was 130 and 60 kg N ha-1 during the growing season for raw and treated wastewater, respectively. As the results showed wastewater can use as a source of N for crops and it can help to reduce the requirements for commercial fertilizers, and decrease their negative environmental impacts. It is suggested that the model parameters can be measured practically, in order to be used for model calibration and validation. Besides, the simulation can be done for a longer period of time to evaluate the effect of rainfall and different cultivations on solute transport.