مجله تحقیقات آب و خاک ایران
سال پنجاه و ششم شماره 2 (پیاپی 110، اردیبهشت 1404)

This research was carried out with the aim of introducing the most suitable accessions in T. kotschyanus and T. lancifolius species of the thyme genus for the development of cultivation in low salinity water and soil conditions at the Pardisan Salinity Research Station of Qom. The seeds of 7 accessions along with the control (T. vulgaris) were planted in the greenhouse and in GF pots in January 2016, and in April of the following year, potted seedlings were planted in the main field in complete randomized block design in three replications. In this experiment, aerial organ function, percentage and yield of essential oil in two years and the percentage of essential oil compounds in the second year were measured and determined. Essential oil extraction was done by water distillation method and essential oil analysis was done by gas chromatography method. The results of composite variance analysis of traits showed that the effect of population, year and the interaction of year in population were significant in all traits at the probability level of one or five percent. The results of the comparison of the average traits in the investigated species showed that the average T. lancifolius species was superior to the average of the other two species in terms of essential oil yield in the first, second and second years. Among the four populations of T. kotschyanus, populations 5 and 70 were superior to other populations of this species in terms of percentage and yield of essential oil. Population 48 of T. lancifolius species was superior to other populations in terms of many traits alone or with population 45 of the same species. In total, 48 and 45 populations of T. lancifolius species from Khorramabad and Faridunshahr regions, respectively, and 5 and 70 populations of T. kotschyanus species from Qazvin and Urmia regions, respectively, can be used for the development of cultivation in areas with brackish water and soil. and also be introduced as candidates for the introduction of promising cultivars of these species in these conditions. Carvacrol chemotypes were identified in Qazvin 1 and 2 accessions, thymol in Naqdeh accession and geraniol in Qazvin 1 accession.

The production of compost from biodegradable urban waste is one of the waste management methods. This research aimed to evaluate the quality of composts in the country. samples were collected from compost produced in factories in Mashhad, Kermanshah, Tehran (first and second grade from Kahrizak), Tabriz, and Isfahan (Isfahan, Shahin Shahr, Lenjan, and Najafabad) over a period of two years. The samples were analyzed for nitrogen, phosphorus, potassium, total lead, total nickel, total chromium, total cadmium, total arsenic, total cobalt, foreign materials, moisture, electrical conductivity, and acidity. none of the composts produced in the country met the standard conditions and failed to comply with the Iranian national standards in at least one or more parameters. The average concentrations of cadmium, lead, nickel, chromium, cobalt, and arsenic in the samples were 3.27, 134, 69, 76, 7.90, and 3 mg/kg of dry weight, indicating non-compliance rates of 6.5%, 16%, 11.2%, 9.47%, 0.59%, and 0%, respectively. The pH had an average of 7.32, showing a 13.4% non-compliance with standards. Electrical conductivity (EC), organic carbon (OC), carbon-to-nitrogen ratio (C:N), nitrogen (N), phosphorus (P2O5), potassium (K2O), and moisture content averaged 5.71, 20.7, 12.7, 1.81, 1.01, 0.96, and 23.6%, respectively, indicating non-compliance rates of 10.7%, 80.5%, 68%, 36.4%, 96.7%, 0%, and 31.4% compared to first-grade compost. it is necessary to evaluate and improve the quality of produced composts concerning organic carbon content and heavy metals, especially lead, to address the non-compliance issues in agricultural usage.

Understanding river water quality is essential for the planning and protection of water resources. Benthic organisms, especially macroinvertebrates, serve as accurate indicators of water quality conditions. In this study, six stations along the Aras River—three upstream and three downstream of the city of Agarak—were selected to assess water quality using the IRWQISC and NSFWQI indices, as well as biological indices including BMWP, ASPT, FBI, and Shannon-Wiener. Sampling was conducted in the autumn of 2022, and various parameters such as turbidity, water temperature, dissolved oxygen, nitrate, total phosphate, fecal coliform, BOD₅, EC, and pH were measured. A total of 21 macroinvertebrate taxa were identified, with Station 2 showing the highest diversity (17 taxa) and Station 4 the lowest (7 taxa). According to the NSFWQI, water quality at Station 1 was rated as good, while the remaining stations showed moderate quality. The IRWQISC index classified Stations 1 and 3 as having moderate quality and the others as relatively poor. The BMWP index rated the first three stations as moderate and the last three as poor. The ASPT index indicated probable moderate pollution at Stations 1, 2, 5, and 6, and probable severe pollution at Stations 3 and 4. The HFBI rated water quality as good at Stations 1, 3, 4, and 5, poor at Station 2, and fair at Station 6. The Shannon-Wiener index revealed a decline in water quality from Station 1 to 3, followed by an improvement downstream. Correlation analysis showed positive relationships between turbidity, BOD, nitrate, and phosphate. These results indicate pollution downstream of Agarak and a decrease in water quality likely caused by a local environmental pollution source, which has altered the macroinvertebrate community and ecological conditions of the area.

Accurate and reliable runoff forecasting has an important role in water resources management, but the complex nature of this parameter can create major challenges for the development of appropriate forecasting models. Two hybrid models based on the combination of two simple linear and non-linear models have been proposed for runoff modeling at hydrological station 02PL005 in the St. Lawrence River basin in Canada. Seasonal autoregressive moving average (SARIMA) linear model is proposed to address the linear and seasonal characteristics of runoff. While the artificial neural network (ANN) and Outlier Robust Extreme Learning Machine (ORELM) models have been used to deal with the nonlinear characteristics of the data through machine learning and pattern recognition. In order to increase the accuracy of the modeling, in the first stage of modeling, the normality and stationary of the data was examined, and by performing appropriate pre-processing, the data were prepared for modeling in the linear part. Then by defining different sub-scenarios and performing modeling through linear model, the best linear model was selected through different mathematical statistics including MAE, RMSE, R and AIC. In the final stage, the residuals of the linear model were modeled by two non-linear models including ANN and ORELM models. Comparing the results of the proposed hybrid models showed that the SARIMA-ORELM hybrid model with AIC=249.29, R=0.71, MAE=11.2 and RMSE=14.33 performs better than the SARIMA-MLP model in all mathematical criteria. Also, the results of the hybrid models were compared with the common MLP, ORELM and SARIMA models.

This research aimed to determine the soil erodibility factor (K) of the Universal Soil Loss Equation (USLE) by direct measurement of soil loss at natural runoff plots (), and to compare it with the estimated K by the USLE-nomograph (). The research carried out at the Sanganeh Soil Conservation Research Site located in the northeast of Iran, in dry rangelands. The soil loss data were obtained from 19 plots with lengths of 20 and 25 m, and different conditions in terms of soil, slope, vegetation cover, and rock fragments under 20 natural rainfall events. The results showed that average intensity and the maximum 30-minute intensity had a greater correlation with soil loss compared to the . Based on the results obtained,  is at least 24, 7, and 6 times of , obtained using the soil loss data of the long-term average, the year with the largest share, and the most intense event (), respectively. The main reasons likely for this overestimation are the low intensity of erosive events and the resulting uncertainties in the measurement of soil loss and other USLE model factors in dry rangelands. Therefore, based on the overestimation of the USLE nomograph, more research, especially with a longer statistical period or using a rainfall simulator with an intensity of 63 mm h-1 in field, is needed to develop appropriate relationships to estimate the K factor in rangelands in dry regions.

In calcareous soils of arid and semi-arid regions, low organic matter, high calcium carbonate content, and high pH reduce microbial activity and decrease the availability of nutrients, especially phosphorus, which in turn limits plant growth. This research aimed to investigate the effects of biochar derived from green sugarcane residues and biochars modified with FeCl2, ZnCl2, citric acid, and oxalic acid on some chemical and biological properties of a calcareous soil. The experiment was conducted in a completely randomized design with six treatments, including: 1- Control (C) (without biochar), 2- Unmodified biochar (B), 3- Biochar modified with citric acid (CAB), 4- Biochar modified with oxalic acid (OXB), 5- Biochar modified with ZnCl2 (ZnB), and 6- Biochar modified with FeCl2 (FeB), with three replications. The biochar was prepared at 350°C and, after chemical modification, mixed with 300 grams of soil at a rate of 1%. The samples were maintained at a constant temperature (25±2°C) for three months. At the end of the experiment, some chemical and biological properties of the soil were measured. The results showed that the application of biochars led to a decrease in soil pH (0.03-0.66 units), an increase in electrical conductivity (0.13-0.57 units), cation exchange capacity (17.0-43.9%), total organic carbon (2.21-2.29-fold), available phosphorus concentration (52.1-96.2%), soil microbial respiration (42.9-69.3%), and soil microbial biomass carbon (54.2-93.7%). Among these, the biochar treatment modified with citric acid had the most positive impact on the examined properties. Overall, biochar derived from green sugarcane residues and modified with citric acid could be effective in the soil organic matter, phosphorus availability, and soil biological properties under the studied soil conditions.

A pot experiment was conducted to investigate the effect of foliar application of Zargreen organic liquid fertilizer on the growth, chemical composition, and water productivity of maize (cv. Single cross) under drought stress conditions from November to March 2021. Treatments consisted of four levels of foliar application of Zargreen amino acid fertilizer (0, 2.5‰, 5‰, and 7.5‰), and three levels of drought stress (100%, 75%, and 50% of the field capacity as no stress, moderate stress, and severe stress, respectively). During the growing season, in 1.5, 3, and 4 months after planting, the fertilizer solution was used for foliar spraying. Data was statistically analyzed and the effect of treatments was also studied using principal component analysis. The highest greenness index and fresh weight of cob were obtained with foliar application of 5‰ organic fertilizer under the highest drought stress conditions. The lowest number of leaves, fresh weight, and plant height were observed at the highest level of drought stress, which was improved by foliar application of the organic fertilizer. With the increase of drought stress, the shoot concentration of copper, manganese, and zinc increased due to the decreased plant dry weight under drought conditions. The highest concentration of these elements in the aerial parts of maize under drought stress conditions was obtained by the high foliar application of the fertilizer. The highest water productivity was obtained with the foliar fertilizer application at the rate of 5‰ under the highest drought stress conditions. The results showed that the most positive correlation between the studied properties was obtained with foliar application of 5‰ of the organic fertilizer. It can be concluded that foliar application of the organic fertilizer has increased the plant's dry weight and reduced water consumption, consequently improving water productivity by helping plants save more water and supplying essential nutrients to plants.

This study investigates the hydraulic characteristics of flow, including flow velocity, pressure, and cavitation index, at various inflow rates using FLOW-3D. The results indicate that as flow passes over the ogee spillway, the flow velocity increases, and this upward trend continues gradually along the chute section. Due to the steep slope of the chute section, the maximum flow velocity occurs here and is eventually dissipated upon entering the stilling basin, where dynamic energy is absorbed. Longitudinal pressure distribution along the spillway reveals a reduction in pressure from upstream to downstream, with the most significant decrease occurring at the downstream end of the chute. The maximum flow velocities at inflow rates of 300 (minimum design discharge), 830 (10,000-year flood discharge), and 2270 m³/s (maximum probable flood, P.M.F.) were recorded as 34.25, 41.80, and 44.90 m/s, respectively, at the downstream end of the chute. Additionally, the minimum flow pressures for these discharge rates were 1.23, 1.52, and -5.9 kPa, respectively. Examination of the cavitation index along the channel bed indicated that cavitation occurs in the chute section under all inflow conditions. However, the cavitation index assessment on the sidewalls showed that the ogee, chute, and initial sections of the chute sidewalls remain unaffected by cavitation. Conversely, the cavitation index in the downstream chute sections decreases below the critical threshold, indicating potential cavitation risk in these regions. Therefore, to prevent the occurrence of the destructive cavitation phenomenon, the implement of flow aeration method from the floor and sidewalls of the channel is recommended.

The effect of Trichoderma fungus, humic acid and phosphorus sources on soil phosphorus availability and its effect on growth characteristics and phosphorus uptake of tomato plant was investigated in a greenhouse experiment. The experimental factors were 1) fungus (with and without Trichoderma koningii), 2) humic acid (0, 2 and 4 g kg-1 soil) and 3) phosphorus treatment (without phosphorus, use of three calcium phosphate and simple superphosphate. The highest values of fresh and dry weight of shoots and roots and chlorophyll index of the plant were observed in the treatment of fungus, 4 g kg-1 of humic acid and the application of simple superphosphate. Fungi inoculation led to increase the amount of root phosphorus uptake in soil treatment of without phosphorus, treated with three calcium phosphate and simple superphosphate by 33.7, 85.9 and 68.8%, respectively. The highest amount of soil available phosphorus and shoot phosphorus uptake was observed in soil treated with fungi, simple superphosphate and 4 g kg-1 of humic acid, which was 58 and 153% higher than the treatment without fungi, phosphorus and humic acid. In general, the combined use of humic acid, Trichoderma and chemical phosphorus fertilizer can be a suitable solution to increase the availability of soil phosphorus and improve the phosphorus uptake and growth of tomato plant.

Meanders in rivers are critical areas for studying flow patterns. Flow within river bends is influenced by centrifugal forces and pressure gradients. Given that rivers exhibit various bed slopes, studying the three-dimensional flow pattern in such channels is of significant importance. The objective of this study was to investigate the three-dimensional velocity components of flow in gentle and sharp 90-degree bends with sloped beds. Experiments were conducted in a channel with central curvature radius-to-width ratios of two, four, and six. Velocity measurements were performed using the Vectrino velocity meter, one of the most advanced instruments for measuring flow velocity. The results indicated that due to the effect of the water's weight component along the bed slope, the maximum longitudinal flow velocity in the initial sections of the bend for gentle bends occurs near the outer wall. However, in the later sections, it shifts closer to the middle of the channel width. Across all Froude numbers and all bends, the transverse velocity profile could be divided into two layers: one near the outer wall of the bend with maximum velocity and another near the inner wall of the bend with minimum velocity, located at 25% of the channel width. It was also observed that by doubling the Froude number from 0.05 to 0.1, the location of maximum shear stress extended from the range of up to 30 degrees to the range of up to 50 degrees of the bend section, and was concentrated near the outer wall.

The main goal of the current research was to develop an optimal cultivation plan for crops in the Tajen catchment basin. For this purpose, two common deterministic mathematical programming models were used, including linear programming and goal programming and non-deterministic gray programming model,.In this regard, information on the time series of selected crops, water resources of the basin and the amount of water consumption in the agricultural sector during the years 2017-2021 from the annual reports of experts Agricultural Jihad Organization and Regional Water Company of Mazandaran Province were collected. The results indicate that the goal model is worse than the linear model in terms of profitability and better than this model in terms of the environment and it can be concluded that the goal model is the middle between the current and linear models. If the criterion for determining the optimal model is profitability and saving in the consumption of inputs that disrupt sustainability, the gray model with an average reduction of 23, 22 and 50%, respectively, in the use of water, chemical fertilizers and agricultural poisons) based on the range of savings in the consumption of the aforementioned inputs) is a more suitable model to recommend. Also, this model guarantees the possibility of earning 21,818 billion rials in gross profit only from the cultivation of barley, grain corn and rice. In addition, linear and goal models cannot provide a suitable program to farmers in the conditions of wet period/drought. Therefore, it is suggested to carry out promotional activities in order to raise awareness about the benefits of implementing the gray model on the water and soil of the region and the income of farmers.

This study aims to synthesize and investigate the effect of hydrochar modified with zero-valence zinc nanoparticles and stabilized with sodium citrate (HC@nZVZ@SC) on removing cadmium from an aqueous solution under the influence of factors affecting the removal. For this purpose, the effective factors on removal include adsorbent dose, contact time, initial concentration, and pH using the response surface method (RSM) based on the central cube design (CCD) to optimize the removal of cadmium (Cd) ions by HC@nZVZ@SC from aqueous solutions. Also, SEM-EDX, FTIR, and XRD methods were used to check the successful loading of zero-valent zinc nanoparticles on hydrochar. SEM-EDX, FTIR, and XRD results showed that zero valence zinc nanoparticles were successfully loaded on hydrochar. The low P value (<0.0001) and high R2 (0.98) showed that the prediction of cadmium removal from aqueous solution by the adsorbent was done well and with high accuracy by the CCD model. The results showed that the optimal removal of cadmium was achieved at pH = 7, the initial concentration was 75 mg/L, the contact time was 60 minutes, and the adsorbent dose was 1.5 g/L, which was 91.35%. In general, the results of this study showed that hydrochar modified with zero-valent zinc nanoparticles and stabilized with sodium citrate can be used as an inexpensive and high-efficiency adsorbent in removing heavy metals from wastewater. Also, the central cube design should be used as an efficient and low-cost method in modeling and optimizing the removal of pollutants from aqueous solution.

Reliable estimation of changes in water quality parameters in the country's reservoirs is important for efficient planning and exploitation of water resources on a temporal and spatial scale.  In this study, firstly, the evaluation of the changes in the water quality parameters of Khoda Afarin Dam at the two inlet and outlet stations to the dam during the study period of the water year 1400 and 1401 was considered. Then IRWQI, NSFWQI and CWQI indexes were used to identify and classify water quality for different uses. According to the obtained results, the maximum values of water quality parameters, including turbidity, total coliform, nitrate, TDS, TSS, EC, DO, BOD5 and COD are respectively equivalent to 5900 (NTU), 35000 (MPN/100 ml), 11.3, 1001.7, 5580, 1590 (us/cm), 12.3, 5.5 and 32 (mg/L) were estimated. According to the obtained results, the BOD at the outlet of the dam is reduced by 10.3% compared to the inlet. The reason for its decrease compared to the inlet station is the decrease in the decomposition of organic matter and its conversion into inorganic compounds, which can be attributed to the activity of bacteria. The average value of COD for the inlet and outlet of Khodaafrin Dam was calculated as 13.4 and 13.8 mg/lit, respectively, which shows an increase of 2.9%. By evaluating the values of water quality indicators, it was found that the range of changes of IRWQI and NSFWQI indicators at the outlet of Khodaafrin dam was between 39 to 72.4 and 54 to 78, respectively. Also, based on the CWQI index, this value was calculated as 40, which indicates the improvement of water quality at the outlet of the dam.

Different composition of vegetation can have significant effects on the variability of soil characteristics. Therefore, the present study was aimed to reveal the effect of the canopy composition of shrub species on soil quality indicators. The different characteristics was studied for the litter and the soil covered with a mix of four shrubs species (Crataegus nigra, Berberis integerrima Bunge, Ribes Uva – crispa L and Prunus spinosa L.), three species (Crataegus nigra, Berberis integerrima Bunge and Ribes Uva – crispa L.), two species (Crataegus nigra and Berberis integerrima Bunge), shrub cover with the predominance of Berberis integerrima Bunge. and Crataegus nigra. For this purpose, in each of the habitats studied, 3 sample plots of one hectare were selected with at least 600 meters distances, and in each sample plot, 5 samples of litter and soil were collected, and a total of 15 samples of litter and soil were collected from each habitat. The results showed significant effects of different Composition of vegetation on most litter and soil characteristics; so that, the highest carbon to nitrogen ratio of litter belongs to the habitat with predominance of Berberis integerrima Bunge (24.46). The highest characteristics of porosity, soil stability, clay, moisture content, carbon and organic matter, storage of carbon and nitrogen, nitrogen, potassium, calcium, magnesium, mineralization of nitrogen, ammonium, nitrate, particulate organic C and N, dissolved organic C and N, activity of enzymes, soil organisms, basic and substrate induced respiration, microbial biomass of carbon, nitrogen and phosphorus were observed in the composition of a canopy with four species. The results of principal component analysis showed that the habitats with high soil fertility and biological activity belonged to the canopy composition with four species. The results of this research indicate that the composition of vegetation with four species can maintain soil quality.

As the global demand for water resources increases, the reduction in water loss, including Evapotranspiration, becomes more obvious. Although many models have been developed to predict evapotranspiration, no universally accepted model for all climate regions has been established. Several soft computational models have been created to circumvent the constraints of empirical models and accurately predict ET. Soft computing models typically require less data and are applicable across various climatic zones. This study aimed to analyze how well two Random Forest models and Multiple Linear Regression could predict ETo in the Ardabil plain region. Meteorological data from the Iranian Meteorological Organization were used to calculate the reference evapotranspiration from 2014 to 2016. In constructing the model, data from 4 meteorological stations were combined to generate a random time series, while the fifth station was reserved for evaluating the models. The assessment metrics used comprised RMSE, R2, and NSE. The RF model achieved higher accuracy with R2, NSE, and RMSE values of 0.74, 0.743, and 8.20 mm, respectively, compared to the MLR model. The results demonstrate that random forest models are reliable tools for forecasting ETo with minimal climate data. In general, using the results of this study and other similar research, we conclude that RF and MLR models simulate potential evapotranspiration with acceptable accuracy but are sensitive to the number of input parameters.