Research Article
Soil science
Jalal Sadeghi; Amir Lakzian; Akram Halajnia; Mina Alikhani Moghadam
Abstract
Introduction The rapid growth of technology, industry, and the rapid development of cities has led to an increase in heavy metal pollution in freshwater sources and greywater in the world. The use of different adsorbents in order to remove some heavy metals from aquatic environments is a topic that has ...
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Introduction The rapid growth of technology, industry, and the rapid development of cities has led to an increase in heavy metal pollution in freshwater sources and greywater in the world. The use of different adsorbents in order to remove some heavy metals from aquatic environments is a topic that has been addressed many times in different studies. However, the use of inexpensive absorbents with high adsorption capacity and high efficiency is the priority of many researchers especially when they are discussing the removal of heavy metals from the aquatic environment. Nanomaterials by having exceptional properties such as high efficiency of adsorption, high specific surface area, and fast adsorption can be used to remove metal pollutants from aquatic environments. Carbon dot (CD), among various nanomaterials (carbon-based nanomaterials (CNM), including carbon nanotubes (CNTs), graphene) are suitable adsorbents for heavy metals removal due to their specific surface area and many binding sites. Carbon dots are dimensionless nanoparticles categorized as carbon nanomaterials with >10 nm in size. CDs have several characteristics such as eco-friendly, easy to synthesize, high biocompatibility, high stability and quenchable (on/off) emission with excitation wavelength that can be functionalized based on their desired applications with a high carbon content (up to 99.9%) These attributes of CDs have made them a motivating substance to a wide range of investigators. In this study, the influence of the fungal carbon dots on the adsorption capacity and kinetics, isotherms, and thermodynamics of lead was investigated.Materials and Methods Alternaria alternata provided by the Department of plant protection at Ferdowsi university of Mashhad. It was re-cultured and fungal exopolysaccharide was extracted and then it was converted into carbon dot using the hydrothermal method. Fungal exopolysaccharide autoclaved in a Teflon container at a temperature of 200 °C. Lead adsorption of synthesized fungal carbon dots was investigated. Lead adsorption tests by fungal carbon dots were performed in laboratory conditions. Lead concentrations (100, 200, 300, 400, 500, 750 and 1000 mg/L), contact time (5, 10, 15, 20, 25, 30 and 60 minutes), pH (2, 4, 6, 7, 8, 9, 10 and 11), amount of carbon dots (nanosorbent) (50, 100, 200, 300, 400, 500, 750 and 1000 mg), ionic strength of the solution (0.1, 0.01 and 0.001 M potassium chloride) and solution temperature (25, 30, 35, 40 and 45 °C) was considered for kinetic tests. The data obtained from the kinetic tests were fitted using non-linear regression analysis using Statistica 7.0 software with the kinetic models of intraparticle diffusion, Lagergren (pseudo-first order) and pseudo-second-order. Thermodynamic results were calculated from the data of lead adsorption isotherms at temperatures of 25, 35 and 45 °C. Thermodynamic parameters to analyze the effect of temperature on metal adsorption, such as free energy change, enthalpy change and entropy change, were estimated using thermodynamic equations.Results and Discussion The initial lead concentration had a great effect on the adsorption rate it by carbon dot, and the highest and lowest percentage of lead adsorption with values of 90.65 and 44.2% were observed in two concentrations of 300 and 1000 mg/liter of lead, respectively. With the increase of pH up to 8, the amount of lead adsorption by fungal carbon dot increased significantly, however, with the increase of pH, the trend was reversed and the amount of adsorption decreased. The results showed that of lead adsorption by carbon dot increased with the decrease of potassium chloride molarity. By increasing the amount of carbon dot in the solution, the amount of lead adsorption increased, and the highest adsorption was observed at the concentration of 300 mg/liter of carbon dot. The results of the experiment also showed that with the increase in temperature, the adsorption rate increased at first and then decreased. Based on these results, with the increase in contact time of the absorbent with lead, the amount of adsorption by carbon dot increased, with the maximum adsorption observed in 25 minutes and this time was considered as the equilibrium time. As shown in the results, the pseudo-second-order model shows the kinetics of Pb adsorption better than the two pseudo-first-order models and intraparticle diffusion. In this model, R2 values are between 0.9989 and 0.9994, and Qe is almost equal to the equilibrium value. According to these results, the values of G decrease with the increase in temperature, which means that the adsorption of lead increases with the increase in temperature, which shows that the adsorption process is more favorable with the increase in temperature, or in other words, it is a spontaneous reaction. Also, the positivity of the reaction enthalpy value (H) shows the endothermic nature of the adsorption process. The positivity of the entropy value (S) indicates the increase of disorder of the system between the adsorbent material and the solution during the process of lead adsorption by the carbon dot.Conclusions In total, the results showed that the carbon dot is a very good absorbent for removing lead from the water environment. In the experimental condition when the initial concentration of lead was 300 mg/L, temperature was 25 °C, adsorbent concentration was 0.3 g/L, reaction time was 25 minutes, and pH 8, the amount of lead adsorption increased significantly. It seems that fungal carbon dot is a safe and relatively cheap adsorbent and suitable for removing lead metal from the solution environment.
Research Article
Soil science
zohreh mosleh Ghahfarokhi; Abolfazl Azadi
Abstract
Introduction Soil properties play a crucial role as they determine the soil's suitability for different types of plant growth, ecosystems, and biota functioning. They have a significant impact on nutrient cycling, carbon sequestration, and soil management. Digital Soil Mapping (DSM) is a process aimed ...
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Introduction Soil properties play a crucial role as they determine the soil's suitability for different types of plant growth, ecosystems, and biota functioning. They have a significant impact on nutrient cycling, carbon sequestration, and soil management. Digital Soil Mapping (DSM) is a process aimed at delineating soil properties. Soil sampling for DSM serves as a fundamental step in improving prediction accuracy and is crucial for incorporating variability in terms of environmental covariates. Conditioned Latin Hypercube (CLH) sampling is a technique utilized to generate a sample of points from a multivariate distribution conditioned on one or more covariates. Numerous researchers (Ramirez-Lopez et al., 2014; Adhikari et al., 2017; Zhang et al., 2022) have endorsed this approach in their studies, following its inception by Minasny and McBratney in 2006. However, there has been limited research to date on the impact of the Latin hypercube method's random sample selection process on the accuracy of resulting maps. Hence, the central question remains: Is the Latin hypercube sampling method, which is currently widely adopted, always a dependable approach in this field? Materials and Methods The study area covers longitudes 50°35'47'' to 51°29'' east and latitudes 31°36''31'' to 32°15'48'' north in Borujen city, Chaharmahal, and Bakhtiari Province. The region, with an average elevation of 2338 meters above sea level, receives an annual rainfall of 250 millimeters and maintains an average temperature of 11.5 degrees centigrade. . In this investigation, inherited data from soil studies were utilized, consisting of 250 samples distributed across the study area. In this research, the examined characteristics in this research include percentage of equivalent calcium carbonate, clay, and soil organic carbon at a depth of 0 to 30 cm. Land component variables were extracted using the Alus Palsar digital elevation model with a spatial resolution of 12.5 meters. In the initial stage, digital maps of equivalent calcium carbonate, clay, and soil organic carbon were generated using the support vector machine method. The modeling process proceeded until a highly accurate model was achieved, with the root mean square error percentage (RMSE%) being less than 40. The Latin hypercube approach was utilized for sample design, with 500 repetitions in this study. After selecting sampling points for each run using the Latin hypercube method, these points were mapped onto a detailed map, and the corresponding feature values were retrieved. The final map was created based on the extracted points. Subsequently, the latin hypercube approach was employed to generate soil property maps for each selected dataset. Validation was conducted using criteria such as the coefficient of explanation, root mean square error, and root mean square error in multiple iterations to ensure the accuracy of the generated maps.Results and Discussion The results distinctly illustrates the varied selection of sampling positions with each implementation of the latin hypercube method. It is important to note that there may be some overlaps in different implementations. Consequently, the primary question arises: Is a one-time execution of the Latin hypercube sufficient for selecting study points? The findings indicatethat the support vector machine model achieves satisfactory accuracy for all the examined characteristics. In the studied area, the environmental factors such as slope and elevation were identified as as significant predictorsfor estimating percentage of equivalent calcium carbonate.Conclusions In the present study, the accuracy of the latin hypercube method was assessed for selecting sampling location for digital soil mapping endeavors in Chaharmahal and Bakhtiari Province. Given the impracticality of collecting numerous field samples to evaluate the soil sampling method, this research aimed to employ simulation methods based on highly accurate maps for this purpose. The results indicate that the different outputs of the Latin hypercube method influence the accuracy of modeling, although this effect is also influenced by the specific feature under investigation and the extent of its variability within the study area. Considering that the latin hypercube method is based on the principle that the samples are randomly selected in each class of environmental parameters, it is suggested that in the future studies where the latin hypercube method is to be used, this should be considered. Adequate consideration should be given, and the selection of sampling locations should rely on multiple implementations of the Bhattacharya distance method to ensure robustness and reliability.
Research Article
Agricultural Meteorology
Mobina Abdollahi Fuzi; Bahram Bakhtiari; Kourosh Qaderi
Abstract
Introduction Spring frost is considered an important threat to agricultural products in high and middle latitudes. The damage caused by the LSFs (Late Spring Frosts) significantly affects vulnerable plant organs markedly affects. This event has caused more economic losses to agriculture than any other ...
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Introduction Spring frost is considered an important threat to agricultural products in high and middle latitudes. The damage caused by the LSFs (Late Spring Frosts) significantly affects vulnerable plant organs markedly affects. This event has caused more economic losses to agriculture than any other climatic hazard in Asia, North America, and Europe. Also, these phenomena have contributed to low crop yields in Iran. The latest statistics released by the Food and Agriculture Organization of the United Nations (FAO) show that Iran is one of the largest producers of agricultural products and the world’s second-biggest producer of pistachios. Kerman province is one of the significant areas of pistachio production. This province has a large share of the pistachio word area plantation. Pistachio spring frost damage resulted in low yields crop yields in the last few years. An important principle in the study of frost is the estimation of this phenomenon. In this study, artificial neural network method methods have been used to estimate late spring frost in the pistachio crop of Kerman city.Materials and Methods In this study, the efficiency of this method was investigated in the estimation of Minimum temperature. For this purpose, the Daily data of the synoptic station of Kerman City were obtained from Iran Meteorological Organization from 2000 to 2020. Meteorological data including mean, maximum, and minimum temperatures, relative humidity, wind speed, saturated vapor pressure, and sunshine hours were used. Five different combinations of these variables was considered as input variables in artificial neural network method for minimum temperatures modeling. After entering data into network and modeling with each combination, RMSE and R2 values were calculated. Finally, the combination of 8 variables including average and maximum temperature, the minimum temperature the previous day and two days prior, relative humidity, wind speed, saturated vapor pressure, and sunny hours were selected as the most suitable combination of variables. Then the simulation of the minimum temperature values with %10 of the data was done. The performance of the methods was evaluated using statistical indices of coefficient of determination (R2), mean square of error (RMSE), Mean Bias Error (MBE), and Coefficient of Nash–Sutcliffe (NSE).Results and Discussion The accuracy of an analytical method is the degree of agreement of test results generated by the method to the true value. By examining the models, the M1 model was found to be the best model due to the lowest RMSE and higher R2. ANN model results were evaluated using various performance measure indicators. The simulated outcome of the model indicated a strong association with actual data where the correlation coefficient above 0.95 and the MBE index is zero was observed. Also, the RMSE value is positive and close to zero, and the NSE value is above 0.75. Therefore artificial neural network method has high accuracy. In this study, mean annual minimum temperature was estimated using artificial neural network models (from March 10 to May 20 comparison between the observed and calculated data showed that these data are in good agreement. Also, the results showed that temperature fluctuations were high between March 10 and March 31. From 2011 to 2017, an almost uniform temperature trend has been observed between March 10 and March 31. But the years 2000, 2006, and 2020 showed a noticeable decrease in temperature. From 2018 to 2020, this trend of temperature reduction has continued. In April, the temperature values were between 7 and 10 degrees Celsius. The years 2001, 2005, 2006, 2009, 2016, and 2019 have had a noticeable decrease in temperature. In May, the mean minimum temperature was between 10 and 14 degrees Celsius. Therefore, the probability of frost occurrence in early-flowering cultivars was higher in late March than in April and May. The years 2000, 2004, 2005, 2012, 2015, 2019 and 2020 had the highest number of frost days in the last two decades.Conclusions The results showed that the artificial neural network method had a high performance in estimating the minimum temperature. The values of the statistical indicators were R2=0.963, RMSE=0.027oC, MBE= 0 and NSE=0.966 respectively. In addition, the ANN method performed good in estimating the number of critical days and frost in pistachio crop. The results showed, although reducing the number of input data in models will result in the reduction of their output precision but Data-driven methods can be used as a useful tool for Minimum temperature estimation.
Research Article
Irrigation
Abdorreza Vaezihir; Marzieh Khalkhali; Mehri Tabarmayeh
Abstract
Determination of groundwater resources potential in fractured and karstic formations of West Azerbaijan provinceIntroduction Groundwater is an important resource for domestic, agricultural, and industrial purposes (Andualem and Demeke, 2019). However, the growing population and advanced irrigation technologies ...
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Determination of groundwater resources potential in fractured and karstic formations of West Azerbaijan provinceIntroduction Groundwater is an important resource for domestic, agricultural, and industrial purposes (Andualem and Demeke, 2019). However, the growing population and advanced irrigation technologies have significantly led to increased groundwater exploitation resulting in aquifer depletion. Exploitation of groundwater from fractured rock aquifers using wells to supply drinking water is more sustainable than the utilization of springs with low and variable discharge. In the case of drought and periods of critical condition of water usage, springs of fractured rock aquifers may dry up or decrease making them unreliable water resources to supply drinking water. Over recent decades, the use of fractured rock and karstic units as a remarkable water resource is known as a valuable source of freshwater worldwide. However, these aquifers are extremely vulnerable to contamination due to their unique hydrogeological characteristics and require more protection (Zarvash and Vaezi, 2014). These resources contribute to providing more than 70% of the rural population and around 50% of the urban population with drinking and household demand needs. Since the degree of development of karst landforms varies substantially from region to region, exploring groundwater potential zones in karstic or fractured rock domains across the world is important, which is mostly achieved using evaluating affecting factors in creating the groundwater occurrence. This evaluation is done by incorporating weighted factors such as Weighted Overlay, Weighted Sum, and Fuzzy Overlay and utilizing geographic information systems (GIS) or other remote sensing techniques, which is addressed frequently in literature summarized by Vaezihir and Tabarmayeh (2016); Saff and Kargar (2011); Amiri et al,2021. Considering the importance of this issue, this research aims to investigate the potential of karstic or fractured rock resources in West Azerbaijan to gain more insight into this valuable resource of groundwater. Materials and Methods West Azerbaijan province, with an area of 43,660 km² including Lake Urmia, is equivalent to 2.65% of the total area of Iran and located in the Alborz-Azerbaijan structural zone with a mean annual precipitation of about 370 mL.The maximum temperature of this province, dominated by a semi-arid and Mediterranean climate, is recorded in Shahin Dezh and Miandoab, and the minimum is measured in Chaldoran, and Tekab Metrological Stations, respectively. About 78% of the total area of West Azerbaijan province is formed by karstic units with more spatial distribution in the southern area. This karstic area encompasses 71% of the total province springs with 59% of the total discharge. In the current research, lithology, river drainage and fault density, vegetation cover, slope, slope direction, elevation with precipitation factor, elevation with precipitation area factor , and moisture index as the main factors were regarded as governing factors in the development of karst aquifers, have been considered to evaluate the potential groundwater resources. After the preparation of all affected layers using various data resources including available geological maps digital elevation map of West Azerbaijan Province obtained from the Geological Survey and Mineral Exploration of Iran, Landsat satellite data, the Fuzzy logistic and SUM and Weighted overlay technique has been used to prepared groundwater potential zone.Results and Discussion The groundwater potential zone were determined through combining 9 affected layers in developing the groundwater resource. The results obtained based on emplotying both weighted overlay and SUM were classified into 5 classes in cludingh low, very low, medium, high and veru high potential zone. The index value in SUM methods estimated to be 16.24, 26.24, 24.24, 20.95, 12.13% , while it changes to 22.82, 24.13, 22.14, 16.23,and 14.67 respectively. Overlaying the location of springs as an indicators of groundwater resource on hardrock and karstic domain on generated maps showed that 30.9 and 33.08 percentage of springs fall in area with the high and very high potential zone, respectively. A significant differences on maps generated based on two mentioned technique, partequallry in area classified as low potential zone with 24.13 and 16.24 persent in weighted overlay and SUM. Conclusions Investigation the groundwater potential zone by integrating the layer provided by Fuzzy logic thechnique through two SUM and weighted overlay methods indicated the province of Azerbaijan Arabi has a moderate level of karstification.However, in some areas, there are significantly higher or lower potentials. Keywords: Fuzzy, Groundwater potential, karstic and fractured rock aquifer, SUM, Weighted Overlay Method.
Research Article
s
Safora JafarNodeh; Afshin Soltani; elias Soltani; Amir dadrasi; samaneh Rahban
Abstract
Introduction Accurate knowledge of water balance components is necessary to optimize water consumption in agriculture. On the other hand, measuring water balance components is expensive and difficult. Therefore, the use of models that can simulate water balance values is important for water management ...
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Introduction Accurate knowledge of water balance components is necessary to optimize water consumption in agriculture. On the other hand, measuring water balance components is expensive and difficult. Therefore, the use of models that can simulate water balance values is important for water management in agriculture and water used by plants. Crop simulation models have been turned into essential tools for studying plant production systems. In models SSM-iCrop2, it is presumed that diseases and weeds are optimally managed and will not affect growth and yield. Also, except for the cases in which the model covers the effect of certain nutrients such as nitrogen, in most cases it is presumed that nutrient deficiency is eliminated due to fertilizing. Therefore, parameterized and evaluated models are fit for these conditions. These factors are present in the field and affect crop growth and yield as well as water use. However, in several cases it is required to estimate yield and water balance components and irrigation water volume under grower conditions. Naturally, models parameterized using experiments are unable to simulate these conditions. Therefore, a model must be prepared that can simulate the real conditions of farmers. In this study, the SSM-iCrop2 model has been calibrated for the real conditions of farmers, and the purpose of this study is to use the SSM-iCrop2 model in simulating water performance and water balance for farmers.Materials and Methods In this study, the SSM-iCrop2 model was calibrated for grower s using variables such as yield and harvest index, which are available for grower fields or are cheap to measure. The effect of factors such as pests and diseases, weeds and unsuitable nutrients, density and sowing date entered the model along with the calibration of three parameters of radiation use efficiency, maximum leaf area and maximum harvest index for grower fields. Calibration was done by comparing the performance of farmers against the performance simulated by the model and by changing the parameters of radiation use efficiency (IRUE), maximum leaf area (LAIMX) and maximum harvest index (HIMAX). This calibration was done at Hashem Abad station in Gorgan for irrigated rice (paddy) and wheat. The simulated actual yield was calibrated with the actual yield. Due to the acceptable simulation of actual yields after calibration, it was presumed that other estimates made by the model are also reliable.Results and Discussion Measurement of water balance and other estimates of the model from growth and yield formation in the grower fields is expensive, but the calibrated model can estimate them at a low cost. In this study, it was shown that with the model calibrated for farmers' conditions, other information (such as the volume of irrigation water) that cannot be easily measured can be obtained, with the assumption that the model accurately captures this information as well as performance. It is considered acceptable. To evaluate the simulated real performance model, it was compared with the model against the real performance of farmers (Agricultural Jihad Report) after calibration. In addition to phenology, the SSM model simulates traits related to growth and yield, evapotranspiration values, irrigation water volume, runoff, available soil water during planting and harvesting, cumulative drainage, etc. The output of the model shows the user what amount of irrigation water is needed for a certain amount of performance in a certain place (certain rainfall and transpiration). The results of the irrigation water volume calculated by the model have been compared with the results of the field tests of the previous studies of the researchers of agricultural research centers and it was found that the output results of the model and the observed values are in good agreement.The root mean square error for rice and wheat was 216.6 and 157.6 kg per hectare, respectively, and the coefficient of variation and correlation coefficient were 4 and 85% for rice and 3 and 94% for wheat, respectively. Then, the irrigation water volume estimated by the model was evaluated and validated with the measured irrigation water volume in different crops (in Golestan province and different years). Based on the results of the evaluation, the coefficient of variation and the correlation coefficient for the simulated irrigation water volume were equal to 8.9 and 98% compared with the observed value. Another part of this study shows the daily simulation and the application of the model in this field. This calibration was done for rice (paddy) and irrigated wheat in the fields of Gorgan township, and the simulation and running were done using the meteorological statistics recorded in Hashem Abad weather station, Gorgan. Noting the fact that the actual yield has been simulated with good accuracy after the calibration, it was assumed that the other estimates of the model are also reliable. Thus, the calibrated model estimates them with low cost and appropriate accuracy and can complement field experiments.Conclusions In this study, it was found that the SSM_iCrop2 model, which is calibrated for the conditions of farmers' fields, in addition to simulating traits related to growth and yield, can estimate traits related to water balance with appropriate accuracy. One of the most important estimates of the model is the irrigation water volume under grower conditions which is critical for agricultural planning and adaptation to drought.
Research Article
Agricultural Meteorology
shler Katorani; Mahmoud Ahmadi; Abbasali Dadashi-Roudbari
Abstract
Introduction Dust emission is considered one of the environmental hazards in arid and semi-arid regions. Understanding the effective variables in increasing dust mass density is very important for early warning and reducing the damages caused by it. One of the main and effective variables in the occurrence ...
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Introduction Dust emission is considered one of the environmental hazards in arid and semi-arid regions. Understanding the effective variables in increasing dust mass density is very important for early warning and reducing the damages caused by it. One of the main and effective variables in the occurrence of dust is the geographical and climate characteristics of the origin areas and areas affected by this phenomenon. Feeding the great rivers of Mesopotamia, it has reduced soil moisture. Also, the wind component is one of the reasons for the increase in dust in these areas.Materials and Methods This study has examined West Asian dust from three perspectives spatial distribution, trends, and their relationship with climate variables. For this purpose, the Dust Column Mass Density (DUCMASS) variable output of the MERRA-2 dataset was used to investigate the spatial distribution of the dust mass density trend, and the AgERA5 dataset was used to investigate the seasonal and monthly changes of precipitation, wind speed, and temperature variables from 1981 to 2020. In this study, the modified Mann-Kendall (MMK) trend test method was used to investigate the trend of dust occurrence in the study area, and the Sen's slope estimator (SSE) test was used to investigate the slope of the trend and to better display the changes in dust mass density in the western region. Asia, the results of the SSE test have been examined on a decade scaleResults and Discussion Investigating the possible climate drivers in the changes of dust mass density for different regions by calculating the correlation between the time series of dust mass density and the variables of temperature, precipitation, and wind speed has been investigated. The results showed that there is an inverse correlation between dust mass density and precipitation and a direct relationship between dust mass density and temperature and wind speed. The highest correlations between dust mass density and temperature have been calculated, and this value has reached 0.9 in the warm months of the year. On the other hand, the highest negative correlations have been calculated in the cold period of the year (winter and autumn seasons) between dust concentration and precipitation with a value of -0.7. The correlation coefficient between dust mass density and wind speed in the months of January to May and November to December is mostly above 0.6. This value shows a lower correlation in the summer season.In most months of the year, dust mass density shows an increasing trend in most regions, from March to July, an increasing trend in active dust springs in Mesopotamia, the deserts of Iraq and Syria, the desert of Rub' Al Khali, Ad-Dahna and Al Nufud Al Kabir are observed in Arabia and Thar desert in Pakistan. This increasing trend starts cyclically from the beginning of spring and reaches its peak in June and July, and the intensity of the trend decreases from September and reaches its minimum value in December. The important point is that the cycle of changes in the monthly trend of dust mass density coincides with the cycle of changes in dust mass density. The northern parts of Iran and Turkey have the highest frequency among different months of the year with a decreasing trend of dust mass density. The increasing trend of dust mass density in the spring and summer seasons in Mesopotamia, the deserts of Iraq, Syria, and Yemen, the Sistan Plain, and the Thar desert in Pakistan and the southeast of Iran is significant at the level of 0.05.Conclusions The results showed that the seasonal changes in dust mass density show well the active sources of dust in the studied area. In the spring and summer seasons, the activity of the dust centers located in the west of the study area, including the Rub' al Khali, Ad-Dahna and Al Nufud Al Kabir deserts, Mesopotamia, the deserts of Iraq and Syria, on the dust load entering the west and southwest of Iran. It has an effect. The investigation showed that climate variables play a key role in the variability of dust mass density in the study area so the areas corresponding to the summer north wind and the 120-day wind of Sistan have shown the highest dust mass density in annual variability. The correlation coefficient between dust mass density with temperature and direct wind speed and its correlation with negative precipitation have been obtained. The results showed that dust mass density has an increasing trend in most of the regions, so from March to August (spring and summer), the increasing trend of dust mass density is significant at the level of 0.05. The highest intensity of the increasing trend was observed in the spring and summer seasons in Mesopotamia, the deserts of Iraq, Syria, and Yemen, the Sistan Plain, and the Thar desert in Pakistan and southeast Iran.
Research Article
Soil science
Hanieh Asgari; Mojtaba Barani Motlagh; Seyed Alireza . Movahedi Naeini; Amir Babaei
Abstract
IntroductionWheat is considered the most important grain and one of the vital food products in the country. It has a special role in the food consumption pattern of humans. After nitrogen, phosphorus is the most important nutrient required by plants and plays an important role in the growth, yield and ...
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IntroductionWheat is considered the most important grain and one of the vital food products in the country. It has a special role in the food consumption pattern of humans. After nitrogen, phosphorus is the most important nutrient required by plants and plays an important role in the growth, yield and quality of plants. The efficiency of using phosphorus fertilizers and the availability of this nutrient is considered as a limiting factor for the production of agricultural products in calcareous soils with alkaline reaction of Iran. Since graphene and its oxidized form, with large amounts of active oxygen groups and high specific surface area, have been proposed by many studies as non-toxic and biocompatible materials in the production of compounds with improved efficiency of using nutrient, therefore in order to increasing the efficiency of phosphorus consumption in soil, in this study, phosphorus was loaded on graphene oxide (GO-P). The present study aims to assess the influence of this compound as a source of phosphorus and its mixing with triple superphosphate fertilizer (GO-P-TSP) compared to triple superphosphate soluble fertilizer (TSP) on the amount of water retention of fertilizers in soil and phosphorus concentration in aerial parts of wheat plant.Methods and MaterialsGraphene oxide was prepared based on the modified Hamers method. Then graphene oxide was adjusted to certain pH and iron sulfate as a source of iron ions was added to the graphene oxide suspension with vigorous stirring. The mixture was stirred for one hour and then centrifuged for 30 minutes. After centrifugation, the supernatant was removed and the residue of the compound was dry frozen. In the next step, pH was adjusted with sodium hydroxide (NaOH) solution. Then a certain weight of potassium dihydrogen phosphate salt (KH2PO4) was added to the above suspension. The mixture was stirred for one hour and centrifuged for 30 minutes. After centrifugation, the supernatant was removed and the remains of the phosphorus composition based on graphene oxide were dry frozen. Loading tests were performed in three replicates. pH, EC, bulk density, total concentration of phosphorus and iron and X-ray diffraction spectroscopy (EDS) analysis were measured in the sample of phosphorus composition based on graphene oxide. Then three fertilizer formulations were selected, which include (1) triple superphosphate fertilizer, (2) synthesized phosphorus fertilizer based on graphene oxide, and (3) mixing graphene oxide-phosphorus compound with triple superphosphate fertilizer in a ratio of 50:50% phosphorus.In order to investigate the effect of three fertilizer formulations on phosphorus availability, soil with low amount of phosphorus was selected and physical and chemical properties of the soil sampel were measured at a depth of 0-30 cm. A greenhouse experiment of wheat planting was conducted as a randomized complete design with 3 replications. The treatments included three fertilizer formulations at three fertilization levels (10, 15, and 20 mg/kg) with 3 replications. The control treatment was performed without phosphorus fertilizer. Plants were harvested 72 days after planting, washed with distilled water and dry with tissue paper. The samples were air-dried and then oven dried at 70˚C to a constant weight in a forced air-driven oven. After harvesting, the weight of fresh and dry matter and phosphorus concentration in the soil and aerial parts of the plant were measured. Statistical data were analysed using SAS software (9.4) and the mean values were compared using LSD tests (at 1, and 5% level).Results and DiscussionThe composition of phosphorus based on graphene oxide (GO-P) in powder form had 35.5% of total P2O5, 31.1% of soluble in water P2O5, 19.6 of total iron and 15.28% of total Potassium. The result of EDS analysis confirmed the loading of phosphorus on graphene oxide. The pH of the phosphorus composition based on graphene oxide was 5.8 approximately 2.5 units higher than triple superphosphate fertilizer. The bulk density of the compound (GO-P) was significantly lower than triple superphosphate fertilizer. The EC of the compound (GO-P) was similar to the EC of the triple superphosphate fertilizer. Soil water retention with synthesized phosphorus fertilizer based on graphene oxide (GO-P) is higher than soil (control) and other compounds added to soil. Experimental results show that the addition of prepared fertilizer formulas (GO-P and GO-P-TSP) increases water retention in the soil for a longer period of time, while in the soil without adding fertilizer and triple superphosphate treatment, respectively, from 10 and 11 days, the absorbed water evaporates completely. Therefore, the combination of soil with GO-P and GO-P-TSP compared to the soil without fertilizer and the combination of soil with triple super phosphate (TSP) fertilizer have better water retention behavior. The greenhouse experiment results of wheat planting showed that all treatments were significant (P<0.01). Among all the treatments and measured levels, the control treatment showed the lowest value. The highest concentration of phosphorus in aerial parts of wheat (0.31 percent) and in soil after harvesting (9.5 mg/kg), fresh weight (10.6 gr per pot), dry weight (2.03 gr per pot aerial wheat plants were related to the treatment of phosphorus compounds based on graphene oxide at the level of 20 mg/kg.ConclusionsThe highest concentration of phosphorus in aerial parts of wheat was related to the treatment of phosphorus compound based on graphene oxide at the level of 20 mg/kg. Therefore, with more research in the future to produce "nutritious plants" in sustainable, efficient and flexible agricultural systems, we can benefit from technologies based on carbon materials.
Research Article
Soil science
Amir Hasanzadeh; Mohsen Hamidpour
Abstract
Introduction Layered double hydroxides (LDH) have gained considerable attention for their potential application in agriculture, serving as a slow-release source of essential nutrients for plants. The appraising of LDH as a favorable fertilizer is in the early development, and more studies on the nutrient ...
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Introduction Layered double hydroxides (LDH) have gained considerable attention for their potential application in agriculture, serving as a slow-release source of essential nutrients for plants. The appraising of LDH as a favorable fertilizer is in the early development, and more studies on the nutrient release mechanism of LDH is needed to answer the question of how LDH could replace commercial fertilizers for the stable provide nutrients to plants. Although, several studies on the release of P from LDH exist in the literature, no information regarding ratios M2+/M3+ in LDHs on phosphate release from LDHs is available. So, it is important to raise our knowledge about various parameters like pH and time on the solubility of LDHs. This study aimed to investigate the effects of pH and the ratio of divalent (M2+) to trivalent cation (M3+) on the kinetic release of P from Mg-Al-LDH.Materials and Methods All the chemical substances in this research, such as magnesium nitrate hexahydrate (Mg-(NO3)26H2O) and aluminum nitrate nonahydrate Al (NO3).9H2O were of analytical grade and obtained from Merk (USA). The solutions were made with decarbonated pure water without impurities (electrical resistivity = 18 MΩcm). Two nitrate form of Mg-Al-LDH were synthesized using the co-precipitation method at constant pH by varying the Mg/Al ratio (3:1 and 4:1) in the precursor solution (Everaert, et al. 2016). Briefly, 50 mL of 1M solution containing nitrate salt of divalent (Mg (NO3).6H2O) and trivalent cations (Al (NO3)3.9H2O) in the appropriate ratio (3:1 and 4:1) were added simultaneously for 2h to 400 mL of 0.01M solution of sodium hydroxide-sodium chloride while being stirred vigorously in a nitrogen atmosphere. The pH was kept at 9.5 by adding volumes of 3 M NaOH. Afterward, the material was ripened in the synthesis mixture for 2 h and centrifuged at 3000 rpm for 20 min. The precipitates were washed by three washing-centrifugation cycles with Milli-Q water and subsequently dried at 70 °C. In this study, LDH-HPO42- was made by ion exchange. The LDH-NO3- were treated with 0.05 M KH2PO4 solutions at pH 7.2. The suspensions were shaken end-over-end for 24h, followed by centrifugation, washing, and drying as described above. After digesting the dried LDHs in aqua regia (3:1 HCl/HNO3), the total P concentration of the LDHs was determined. The chemical composition of the synthesized LDHs was determined by furnace atomic absorption spectrophotometry (SavantAA, GBC) after acid digestion (3:1 HCl/HNO3). Crystallization and morphology of the LDHs were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD patterns were prepared using an x-ray diffractometer (Panalytical x Pert Pro, Netherlands). The phase purity was surveyed by comparing these XRD diagrams with those found in the literature. The SEM photographs were gained on a scanning electron microscope (Sigma VP, Germany). Fourier Transform Infrared (FTIR) spectrum was done on a Nicolet iS10 FT-IR spectrometer by utilizing KBr pressed disk technique.A batch study was done to determine the effect of different ratios of M2+/M3+ in LDHs at different pH 6.0, 7.0, and 8.0 on the release of P from LDHs. Briefly, 0.01 g of synthesized LDHs were put in a centrifuge tube mixed with 10 ml of 0.03M KNO3 at initial pH=6, 7 and 8. Suspensions were shaken at a constant temperature (25 ± 0.5 °C) and agitation (180rpm) by using an incubator shaker for 8h. Phosphorus concentration in supernatant solutions was measured by the vanadate yellow method at 470 nm wavelength.In order to investigate the kinetics of phosphorus release, LDH (3:1) and LDH (4:1) were used at two initial pHs of 6 and 8. First, 0.012 g of LDH sample was placed in 120 ml of KNO3 electrolyte solution (with ionic strength of 0.03 M) in an Erlenmeyer flask. The flasks were shaken for 5 to 1175 min by an incubator shaker at 100 rpm. Then the suspensions were centrifuged at a speed of 4000 rpm for 20 minutes and the phosphorus concentration was determined by the previously described method. All experiments were performed with three repetitions. Two equations (pseudo-second-order and parabolic diffusion) were used to fit the kinetics data. Results and Discussion The XRD patterns of the LDHs exhibited a distinct characteristic reflection (003), which indicates that the basal spacing decreased as the Mg/Al ratio decreased (higher AEC). The intercalation of phosphate anions into Mg/Al LDH is in adaptation with the change toward lower 2θ angles of the (001) reflections corresponding to the expansion of the basal distance d003 compared to the host Mg/Al-NO3-. The results showed that increasing the pH from 6 to 8 in the presence of 0.03 M potassium nitrate background electrolyte led to an increase in phosphorus released from both types of LDH. For example, by increasing the initial pH of suspensions from 6 to 8, the amount of phosphorus released from LDH (4:1) increased from 4.61 mg/kg to 9.29 mg/kg. In all studied pHs, phosphorus release from LDH (3:1) in background electrolyte environment was lower than LDH (4:1). For example, at pH 6, 7, and 8, the amount of phosphorus released from LDH (4:1) was 1.48, 2.10, and 2.45 times higher than LDH (3:1), respectively. The cumulative phosphorus release kinetics from the studied LDHs showed that the amount of phosphorus release accelerates with increasing time. Phosphorus release from LDH continued at a higher rate from 0 to 400 minutes in the first stage and at a slower rate during 400-1175 minutes. Also, based on the results, among the studied kinetic equations, pseudo-second-order equations and parabolic dispersion had the best fit on phosphorus release data.Conclusions The results of this research showed that the release of phosphorus from LDH is dependent on time, pH and the type of LDH. Based on the results of fitting the kinetic models to the experimental data, the release rate of phosphorus from LDH (4:1) was higher than that of LDH-P (3:1). Phosphorus release from LDH (4:1) compared to LDH (3:1) was 48, 145% higher at pH 6 and 8, respectively.
Research Article
Soil science
fatemeh jannati; Fereydoon sarmadian
Abstract
AbstractIntroduction:Research and development in high-potential agricultural areas are of great importance for ensuring the food needs of the population and livestock. Neglecting these regions can lead to increased food prices and food shortages, which can have a negative impact on the economy and public ...
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AbstractIntroduction:Research and development in high-potential agricultural areas are of great importance for ensuring the food needs of the population and livestock. Neglecting these regions can lead to increased food prices and food shortages, which can have a negative impact on the economy and public health. Land suitability maps provide essential information for agricultural planning and are vital for reducing land degradation and evaluating sustainable land use. The utilization of modern mapping techniques such as digital soil mapping and machine learning algorithms can significantly improve the accuracy of land suitability assessment and crop performance prediction. These methods have been widely employed as primary tools for mapping and evaluating land suitability in various regions worldwide.Materials and Methods:In this study, a total of 288 soil profiles were utilized to compute the land suitability index for wheat, barley, and alfalfa crops. Various environmental variables were incorporated, including topographic factors derived from the digital elevation model and spectral indices obtained from Landsat 8 satellite imagery. Eight key factors, namely slope percentage, climate, texture, gypsum content, equivalent calcium carbonate, electrical conductivity (EC), and sodium absorption ratio (SAR), were identified as influential in the assessment of land suitability. To quantify the degrees of land suitability for the target crops, a parametric approach based on the square root method was employed. Moreover, the random forest machine learning model was utilized for spatial modeling, zoning mapping, and determining the significance of environmental variables in the land suitability evaluation process. By incorporating these comprehensive methodologies, a more detailed and accurate understanding of the land suitability for wheat, barley, and alfalfa cultivation can be achieved, facilitating informed decision-making in agricultural planning and land management strategies.Results and Discussion:The spatial prediction results demonstrated the effectiveness of the random forest model in classifying land suitability for wheat, barley, and alfalfa. The model achieved high accuracy, with Kappa coefficients of 81%, 84%, and 85% for wheat, barley, and alfalfa, respectively. The overall accuracies were also impressive, reaching 86% for wheat, 88% for barley, and 89% for alfalfa. Analyzing the land suitability assessment results, it was found that barley had the highest land suitability class, covering a significant portion of 40% in class S1. Alfalfa followed closely with 35.5% of the total area, and wheat occupied 32% in the same class. Delving into the predictive environmental variables for barley, Diffuse, SHt, and MrVBF emerged as the most influential factors. These variables played a crucial role in assessing the suitability of land for barley cultivation. Similarly, for wheat, the variables Diffuse, MrVBF, and TWI were identified as significant indicators, contributing to the accurate prediction of wheat performance. Regarding alfalfa, the variables MrVBF, Diffuse, and Valley_depth stood out as the most important variables, providing valuable insights into land suitability for alfalfa cultivation. In general, the limiting factors for irrigated cultivation of these crops were primarily associated with soil properties. In the northern regions, soil texture was identified as a significant limiting factor, impacting the suitability of the land for crop cultivation. On the other hand, in the southern regions, soil characteristics such as the percentage of lime, gypsum, salinity, and alkalinity were recognized as the most influential limiting factors, affecting the suitability of the land for successful crop production. These findings provide valuable information for land planners, farmers, and decision-makers in determining suitable areas for wheat, barley, and alfalfa cultivation. By considering the identified influential factors and addressing the limiting soil properties, agricultural practices can be optimized to maximize crop productivity and ensure sustainable land use.Conclusion:The research aimed to evaluate land suitability for wheat, barley, and alfalfa crops under irrigation. Data selection focused on the most limiting factors for these crops. The model achieved acceptable predictions for wheat, barley, and alfalfa, with Kappa coefficients of 0.81, 0.85, and 0.84, and overall accuracies of 0.86, 0.89, and 0.88, respectively. Barley had the highest percentage of suitable land (40%), followed by alfalfa (39.5%) and wheat (32%). Soil constraints varied across the study area, including texture, stoniness, lime, gypsum, salinity, and alkalinity. The analysis identified 31 soil types, and the random forest model yielded a digital soil map with a Kappa coefficient of 0.76 and overall accuracy of 0.81. The findings support effective land management and agricultural planning.
Research Article
z
Donya Parmah; Hamid Reza Chaghazardi; Farzad Mondani; Ali Beheshti Al Agha; Daniel Kehrizi
Abstract
IntroductionOptimum yield production in rainfed cultivation directly depends on the amount of rainfall and moisture storage in the soil. The tillage system directly affects the moisture storage and the physical and chemical properties of the soil, and choosing the right tillage system affects the yield ...
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IntroductionOptimum yield production in rainfed cultivation directly depends on the amount of rainfall and moisture storage in the soil. The tillage system directly affects the moisture storage and the physical and chemical properties of the soil, and choosing the right tillage system affects the yield of the product. Oilseeds are particularly important among crops, forming the second-largest food reserves in the world after grains. These products are rich in fatty acids. Today, the oil extraction and production industry is one of the most strategic industries in most countries. Iran has vast arable lands and favorable fields for cultivating oilseeds. Still, according to the available statistics, more than 80% of the country's required oil is supplied from abroad. Considering that our country needs more and better quality oil products on the one hand, and the other hand, is involved in climate issues and problems such as consecutive droughts, it seems that the cultivation and development of plants with fewer water requirements and high resistance and providing management methods and appropriate fertilizer in line with conservation agriculture is a suitable solution to increase crop yields and maintain and increase soil quality in the long term. For this purpose and considering the value of oilseed cultivation, an experiment was conducted to investigate the effect of tillage and fertilization on the yield and components of safflower yield in rainy conditions.Materials and Methods The experiment was carried out as split plots in a basic design of random complete blocks, with three replications in rainfed conditions. The treatments included tillage systems (conventional tillage, reduced tillage, and no-tillage) as the main factor and NPK fertilizer (a mixture of urea, triple superphosphate, and potassium sulfate) at four levels of zero, 33, 66, and 100% as a secondary factor. Potassium and phosphorus fertilization and 50% of nitrogen fertilizer were used at the same time as planting, and the remaining 50% of nitrogen fertilizer was used four months after planting. Each block had three main plots; the distance between each block was 3 meters, and between the main plots was 2 meters. In each main plot, four sub-plots were created, and the distance between the sub-plots was 1 meter. The area of the main plots was 21 × 15 meters, and the area of each sub-plot was 4.5 ×15 meters. The amount of seed used for safflower was 25 kg per hectare. The safflower seeds were sown in 5 rows and planted at a distance of 50 cm and a distance between plants of 10 cm. In all the stages of planting, holding, and harvesting, all agricultural management was carried out based on the traditional management of the studied area and in the farmer's way. The final sampling or harvesting was done manually in the physiological treatment stage. Before analyzing the variance of the data, the normality test of the data was performed. In this research, the LSD test was used to compare the mean at the 5% probability level, Excel software was used to draw graphs, and SAS 9.4 software was used to analyze the data.Results and Discussion The research showed that the traits examined, including leaf area index, dry matter content, thousand seed weight, seed yield, and biological yield, were affected by the tillage system, fertilizer, and their interaction effect. The highest safflower seed yield of 195.6 g/m2 was obtained from the fertilizer ratio of 33% and conventional tillage, and the lowest seed yield of 116.2 g/m2 was obtained from no-tillage and no fertilizer use. The results showed that the conventional tillage system had better results than low-tillage and no-tillage. The results showed that in reduced tillage and no-tillage, the changing trend of safflower plant leaf area index was not much different, and only in safflower, the 100% fertilizer ratio in reduced tillage had a more significant effect than no tillage. Also in the condition of no fertilizer use in no-tillage, the leaf area index was lower. The use of fertilizer increased the biological yield of the plant, but the effect of this use in conventional tillage was higher than in reduced tillage and no-tillage. Consumption of 33% of the fertilizer required by the plant under conventional tillage conditions caused the highest biological yield in the safflower plant. So, the biological performance of safflower increased by 94% compared to the control.Conclusions In most of the examined traits, the application of 33 and 66% of the fertilizer requirement caused the best results, and the 100% fertilizer ratio left adverse effects, which indicates the lower fertilizer requirement of this cultivar in the studied conditions compared to cultivars in other regions. Since the research was conducted in rainy years, conventional tillage was better than low tillage. It is suggested that this plant's production amount be evaluated under different irrigation conditions and moisture limitations so that tillage systems and management methods can be examined and selected more carefully.
Research Article
Soil science
Fatemeh Rakhsh; Ahmad Golchin; Ali Beheshti Ale Agha
Abstract
Introduction
Soil texture is one of the most influential characteristics of soils that affect the decomposition and retention of soil organic matter because it directly or indirectly affects soil's physical, chemical, and biological properties. Soil clays play an important role in soil organic matter ...
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Introduction
Soil texture is one of the most influential characteristics of soils that affect the decomposition and retention of soil organic matter because it directly or indirectly affects soil's physical, chemical, and biological properties. Soil clays play an important role in soil organic matter stability. Organic matter adsorbed on phyllosilicate clays is more resistant to microbial decomposition than organic matter that has not interacted with any mineral. Exchangeable cations with the influence of physical and chemical characteristics of the soil probably cause changes in the absorption and retention of organic matter. In previous studies, the effect of soil texture on organic matter retention has been investigated, but the impact of clay type and exchange cation has not been investigated. This study aimed to examine the effect of different contents of vermiculite and zeolite clays and exchange cations on the mineralization of organic nitrogen.
Materials and Methods
A factorial experiment was conducted in a completely randomized design with three replications to study the effect of the type and content of clay and the type of exchange cations on organic nitrogen dynamics. Experimental treatments include two types of clay (vermiculite and zeolite), four different levels of clay (0, 15, 30, and 45%), and three types of exchangeable cations (Na+, Ca2+, and Al3+). The experiment included 24 treatments and three replications. There were total of 72 experimental units. Artificial soil of 50 grams was prepared separately according to the amount and type of clay and the type of exchange cation. Then, alfalfa plant residues were added to all the samples at 5% w/w. After adding the inoculum and air drying the samples, the humidity of the samples reached 60% of the field capacity (FC) using distilled water (We first air-dried the samples to prevent the excess water from causing an error in the final moisture, and then we added enough distilled water to each sample to reach 60% of FC). They were kept in the dark for 60 days at a temperature of 23 °C. Distilled water was added and sealed to the bottom of the incubation jars to keep the moisture content of the soil samples constant during incubation. The percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were determined in the prepared samples. The data were analyzed using ANOVA, and the means were compared using Duncan's Multiple Range Test (DMRT). Before applying ANOVA, the data's normality and variance homogeneity were checked using Kolmogorov- Smirnov and Levene tests, respectively. The SPSS software (Windows version 25.0, SPSS Inc., Chicago, USA) and SAS software (version 9.4, SAS Institute Inc., Cary, NC) were employed for data analysis.
Results and Discussion
The results of variance analysis of the data showed that the effect of the type and content of clay and the type of exchangeable cation on the percentage of mineralized nitrogen, microbial biomass nitrogen, and the activity of acid and alkaline phosphatase and cellulase enzymes were significant (p< 0.01). The results revealed that, regardless of the duration of the samples, with the increase in the amount of clay, the percentage of inorganic nitrogen and the activity of enzymes decreased, but the nitrogen of microbial biomass increased. The highest percentage of inorganic nitrogen was obtained 60 days after incubation of the samples and in clays saturated with calcium, and the lowest amount of these attributes was obtained 15 days after incubation of the samples and in clays saturated with aluminum. The results showed that nitrogen mineralization increased with the samples' incubation time. Also, the highest percentage of mineralized nitrogen, microbial biomass nitrogen, and enzyme activity were observed in soils with vermiculite clay.
Conclusion
The increase in the incubation duration increased the percentage of inorganic nitrogen. The percentage of mineralized nitrogen and microbial biomass nitrogen was higher in soils with vermiculite clay than in soils with zeolite clay. Moreover, regardless of the incubation duration of samples, with increasing clay content, the percentage of mineralized nitrogen and enzyme activity decreased, but with increasing clay nitrogen content, microbial biomass increased. The highest and lowest amounts of mineralized nitrogen and nitrogen of microbial biomass were measured in soils with calcium and aluminum, respectively. The results showed the effect of the clay type and content and the exchangeable cation type on organic nitrogen dynamics.
Research Article
Irrigation
Akbar Khedri; Amir Saberinasr; Nasrollah Kalantari
Abstract
Introduction: The comprehension of the hydrogeological conditions of the aquifer and the determination of its hydraulic characteristics, such as hydraulic conductivity, transmissivity coefficient, and specific storage, are crucial for the management and preservation of groundwater resources. Various ...
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Introduction: The comprehension of the hydrogeological conditions of the aquifer and the determination of its hydraulic characteristics, such as hydraulic conductivity, transmissivity coefficient, and specific storage, are crucial for the management and preservation of groundwater resources. Various conventional methods, including empirical formulas, laboratory techniques (constant and falling head), tracer tests, field tests (Lugeon, Lefranc, slug, flowmeter, and pumping tests), and groundwater inverse modeling, are employed to establish these characteristics, particularly hydraulic conductivity. Empirical formulas are limited to ideal conditions, and in laboratory methods, the sample must be kept undisturbed. Due to the impracticality of measuring large-scale effective factors, the hydraulic conductivity determined through laboratory methods is also the only representative of the hydraulic conductivity at the sampling point. Tracer studies encounter numerous constraints, such as time, cost, porosity determination, and tracer dispersion in multilayered aquifers. It is also difficult to determine the average hydrodynamic properties of the heterogeneous aquifer based on the data obtained from a specific section of the Lefranc and Slug tests. Consequently, pumping tests are commonly selected for hydraulic parameter estimation. Although costly and time-intensive, these tests provide more precise coefficients. Geophysical methods have been greatly developed during the last two decades and have shown a significant correlation with the hydraulic parameters of the aquifer derived from borehole pumping tests or direct laboratory measurements. This approach minimizes uncertainties in numerical model calibration, improves data coverage, and reduces the time and cost of regional hydrogeological investigations. The conventional approach, known as the electrical resistivity method, is still widely used in global and local research projects for evaluating aquifer hydraulic characteristics (Ige et al., 2018; Arétouyap et al., 2019; Youssef, 2020; Ullah et al., 2020; de Almeida et al., 2021; Lekone et al., 2023). Therefore, this study aims to use the integrated approach of the geophysical method and pumping test as a cost-effective and efficient alternative for estimating the hydraulic parameters of the alluvial aquifer in the northeast of Gachsaran city.
Material and Methods: The research area is an alluvial aquifer located 5 km to the northeast of Gachsaran, between coordinates 50-52 to 51-09 E longitude and 30-15 to 30-28 N latitude. Using 86 vertical electrical soundings, Archie's equations, and the IPI2win software, the hydraulic characteristics of the aquifer under investigation were estimated. Subsequently, these characteristics were then compared to the coefficients derived from the data of two pumping test wells, which were calculated using the Aquifer test software and obtained via the Cooper-Jacob and Neuman methods.
Results and discussion: The hydrodynamic coefficients of the aquifer were initially determined using the Cooper-Jacob method in this study. The hydraulic conductivity values for wells one and two are 4.9 m/day and 5.7 m/day, respectively. Correspondingly, the storage coefficient values for wells one and two are 0.015 and 0.021, respectively. Based on the Cooper-Jacob approach, it is deduced that if the storage coefficient values exceed 0.001, the aquifer is classified as unconfined. In this study, the storage coefficient values for both pumping wells suggest that the aquifer is unconfined. Since the vertical flow component and the delayed yield phenomenon should also be taken into account in unconfiend aquifers, the Neuman analytical model has been used in the studied aquifer. The values of specific yield (Sy) for pumping wells one and two, which are related to delayed yield, are 0.05 and 0.04, respectively. These values were calculated by analyzing the first segment of the curve derived from the Neuman logarithmic drawdown-time plot. The storage coefficient values for pumping wells one and two, extracted from the second section of the curve, are 0.015 and 0.021, respectively. Furthermore, the transmissivity value for well number 1 was 323 m2/day, while for well number 2, it was 655.5 m2/day. The vertical electrical sounding (VES) data were subsequently initially analyzed and interpreted using the IPI2win software and the equalization curve method (partial curve matching technique). The coefficients denoted as m and n, indicative of the degree of cementation of the sediments, were determined based on the sedimentary composition prevalent in the area. Archie's equations were employed to calculate the formation factor and porosity parameters. The aquifer exhibits a porosity range of approximately 0.15 in the eastern and southeastern parts (near the outlet of the plain) and around 0.41 in the centeral, northern, and northwestern sections of the area (next to the Asmari Formation). The specific yield (Sy) of the aquifer was calculated using the provided formula:
The minimum and maximum specific yield were estimated as 0.006 (in the eastern and southeastern regions) and 0.089 (in the western and northwestern regions of the plain), respectively, with an average value of 0.04. The transmissivity coefficients for the entire aquifer were then calculated based on the fitted relationship between hydraulic conductivity (K) and formation factor (F):
The range of transmissivity coefficients varies from a minimum of 63 m2/day (in the western and northwestern sections of the plain) to a maximum of 608.9 m2/day (in the eastern and southeastern areas). The average transmissivity coefficient is calculated as 323.7 m2/day.
To ensure the precision of the geoelectric method's coefficients, a comparative analysis was conducted with the hydrodynamic coefficients obtained from the two pumping test wells, as presented in the table below:
Conclusion: The evaluation and comparison of the hydrodynamic coefficients derived from the aforementioned methods indicate that the geoelectric method coefficients exhibit acceptable agreement with the pumping test coefficients. In other words, the analysis of the pumping test conducted using the Neuman technique in the unconfined aquifer revealed that well number two displayed a greater transmissivity coefficient, while well number one presented a higher specific yield. These findings are confirmed by the geoelectric approach. Consequently, such hybrid approaches, which include simultaneous analysis of geophysical methods (such as VES) and pumping tests will be a great alternative to multiple costly pumping tests for evaluating the hydrodynamic coefficients of an aquifer. Moreover, employing this hybrid technique enables the generation of dense hydrodynamic coefficients in an aquifer for use as inputs in the groundwater model.
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