Showing 53 results for Sadeghi
E. Sadeghi, F. Raiesi, A. Hossienpur,
Volume 23, Issue 2 (Summer 2019)
Abstract
Abiotic stresses such as salinity and contamination individually have a negative effect on the soil enzyme activities, whereas addition of organic matter to soil can alleviate the negative impacts of stresses on the enzyme activity. However, the combined effects of these stresses (multiple stresses) on soil biochemical conditions and the role of organic matter addition in these interactions are largely unknown. The objective of this research was to explore the interaction effect of NaCl salinity and cadmium (Cd)-pollution on the activities of catalase, alkaline phosphatase, arylsulfatase and fluorescein diacetate hydrolysis in a Cd-contaminated calcareous soil treated with alfalfa residue over 3 months of incubation. A factorial experiment with 2 levels of Cd, 3 levels of salinity and 2 plant residue treatments was conducted using a completely randomized design with 4 replications. The results indicated that salinity increased the Cd availability in both uncontaminated and contaminated soils and reduced the soil enzymatic activity. Nevertheless, addition of alfalfa residue reduced the detrimental effects of salinity and Cd-pollution on the soil enzyme activities. This indicated that in saline Cd-contaminated soils with low organic matter, adding plant residues could lower the concentration of available Cd and the effect of soil salinity with a concomitant increase of enzyme activities. So, this study showed that the joint effect of NaCl salt and Cd on enzyme activity was mostly synergistic in plant residue-untreated soils, but it was antagonistic in the plant residue-treated soils.
N. Sadeghian, A. Vaezi,
Volume 23, Issue 2 (Summer 2019)
Abstract
Sediment selectivity during transport may provide basic information for evaluating on-site and off-site impacts of the soil erosion. Limited information is, however, available on the selectivity of sediments in rill erosion, particularly in the rainfed furrows. Toward this, the sediment selectivity was investigated in three soil textures (loam, loamy sand sand clay loam) under 10% slope using 90 mm.h-1 rainfall intensity for 40 min. Soil samples were passed from a 10 mm sieve and packed in to the erosion flume with 0.4m × 4 m in dimensions. Particles size distribution (PSD) was determined in the sediments (PSDs) and compared with the original soil PSD (PSDo). The proportion of PSDs and PSDo was stated as PSDs/PSDo to show the selectivity of soil particles by rill erosion. Based on the results, all three soils appeared as the coarse particles (coarse sand and very coarse sand) in sediments with the PSDs/PSDo>1, indicating the higher selectivity of these particles by rill erosion. Loamy sand was the most susceptible soil to rill erosion among the studied soils, which generated a higher runoff (0.0035 m2.s-1) and sediment load (0.1 kg.m-1.s-1) during rainfall. The PSDs of this soil were similar to those of the original soil PSD. This study revealed that the stability of aggregates could be regarded as the major soil factor controlling rill erosion rate and the sediment selectivity in the semi-arid soils. With an increase in the water-stable aggregates, soil infiltration rate and as a consequence, shear stress of flow could be decreased in the rills.
M. M. Matinzadeh, J. Abedi Koupai, A. Sadeghi-Lari, H. Nozari, M. Shayannejad,
Volume 23, Issue 3 (Fall 2019)
Abstract
Selection of drainage equation with acceptable accuracy has always been a challenge for designers to design subsurface drainage systems. In this research, seven steady state drainage equations were used for predicting daily and cumulative drainage rate on a farmland of sugarcane in Imam agro-industrial Company. These drainage equation included Hooghoudt, Ernst, Kirkham and Dagan that have been developed in the past and Mishra and Singh, Henine and Yousfi et al that recently developed. The statistical indices consist of P-value, RMSE, R2 and Percentage Error of estimating cumulative drainage rate were calculated for Hooghoudt equation 0.9501, 1.49 (mm/day), 0.80 and -0.19%, respectively. For Ernst equation 0.0001, 2.46 (mm/day), 0.34 and 16.98%, respectively. The result of performance of drainage equations revealed that Hooghoudt and Ernst equation were as the equations with the highest and lowest accuracy in predicting drainage rate, respectively. Also from the newly developed equations, the Yousfi et al equation was found with relatively well accuracy to predict the drainage rate. This equation was placed in second rank after Hooghoudt equation and other equations showed poor performance. Thus, with selection of the appropriate drainage rate, the Hooghoudt equation is suggested for designing of drain spacing in medium to heavy textured soils such as sugarcane agro-industrial.
N. Sadeghian, A. Vaezi, A. Majnooni Heris,
Volume 24, Issue 1 (Spring 2020)
Abstract
Few studies have been done regarding the role of the raindrop in the hydrodinamic mechanism of soil erosion. In this study, rainfall simulation experiments were conducted to evaluate the role of raindrop in runoff discharge, sediment concentration and hydraulic properties of flow under four slope gradients (5, 10, 15 and 20%) in a clay soil using a 90 mm.h-1 rainfall intensity to reach the steady state flow. Soil sample was packed into the erosion flume with 0.3m× 0.4m × 4 m in dimensions and tested under two soil surface conditions: one with raindrop impact and one without raindrop impact. The results showed that runoff discharge, sediment concentration, flow depth, shear stress, stream power, Reynolds number and runoff velocity under without raindrop impact condition were significantly lower than those in the condition with the raindrop impact with a factor of 0.62 to 3.54, 0.08 to 11.83, 0.91 to 0.96, 0.26 to 3.25, 0.52 to 4.45, and 0.36 to 3.27, 0.23 to 0.79 times, respectively; on the other hand, the Darcy Wysbach, Chezy and Manning coefficients were increased significantly under without raindrop impact (P<0.01). Flow velocity was the key hydraulic parameter strongly affecting the hydraulic properties. These findings indicated the importance of raindrop impact in the detachment rate of soil particles through the change of the hydraulic characteristics. This study also revealed the key role of raindrop impact on the runoff hydraulic characteristics, as well as particle detachments rate in rills. Information about the role of raindrop impact is a substantial step in modeling the rill erosion. Therefore, elimination of raindrops impact, especially in the steep slopes, with the conservation of natural vegetation cover can sufficiently prevent runoff production as well as the particle detachment rate.
A. R. Vaezi, Kh. Sahandi, N. Sadeghian,
Volume 24, Issue 2 (Summer 2020)
Abstract
In semi-arid regions, soils are weakly aggregated and subjected to water erosion processes especially rill and interrill erosion. There is no information on the rate of these water erosion types in semi-arid soils located in the hillslopes. Therefore, this study was conducted to determine the soils susceptibility to these erosion types in semi-arid region. A laboratory experiment was done in eight soil textures using in a 0.6 m × 1 m flume a simulated rainfall with 50 mm.h-1 in intensity for 60 min. Rill and interrill erosion rate was measured using soil loss amount per flume area and rainfall duration. Based on the results, both rill and interrill erosion rate were significantly varied among the soils textures (P<0.001). Silt loam was the most susceptible soil to rill erosion (0.22 g m-2 sec-1) and interrill erosion (0.15 g m-2 sec-1), whereas sand didn’t appear any soil loss by these water erosion types. The compression of soil loss resulted by rill and interrill erosion among the soil tectures showed that rill erosion rate for sandy clay loam, silt loam, loam and sandy loam was 3.2, 1.4, 1.1 and 2.8 times higher than interrill erosion rate, respectively. These differences were statistically significant. Silt content was the major factor controlling soil loss difference in these soils. This study revealed that the study semi-arid soils having higher silt content appears also higher rill erosion rate than interrill erosion rate.
M.m. Matinzadeh, J. Abedi Koupai, M. Shayannejad, A. Sadeghi-Lari , H. Nozari,
Volume 25, Issue 4 (Winiter 2022)
Abstract
Using water and fertilizer management at the farm level can be increased water use efficiency and reduce the volume of drainage water, fertilizer losses, and other pollutants in farmland with deep underground drains such as Khuzestan agro-industrial Companies. In the present study, a comprehensive simulation model for the water cycle and the nitrogen dynamics modeling was used for water and fertilizer management modeling on farmland of sugarcane in Imam Agro-Industrial Company using a system dynamics approach. To reduce irrigation water consumption and nitrogen fertilizer losses, five different scenarios were considered including four scenarios of water management consist of 5, 10, 15, and 20 percent reduction in the amount of irrigation water (I1, I2, I3, and I4) compared to the current situation of irrigation in Imam agro-industrial Company (I0), and one scenario of integrated water and fertilizer management (20% reduction in the amount of irrigation water and urea fertilizer 210 Kg/ha, I4F). The results of modeling showed that the scenario of I4F caused to reduce 31, 70, 71, 70, and 85 percent of the cumulative volume of drainage water, cumulative nitrate and ammonium losses, total losses of cumulative nitrate, and ammonium by tile-drain and cumulative losses of denitrification process, respectively. Thus, the implementation of this scenario, not only saves water and fertilizer consumption but also reduces environmental pollution effectively. So the scenario of I4F (amount of irrigation water for six months 2656 mm and urea fertilizer 210 Kg/ha) is recommended for sugarcane in the Imam agro-industrial Company.
R. Sadeghi Talarposhti, R K. Ebrahimi, A. Horfar,
Volume 25, Issue 4 (Winiter 2022)
Abstract
Protection of rivers’ water quality as the most accessible source of the water supply has always been considered. In this paper, self-purification and the pollution decay coefficient values of Talar River, IRAN were studied based on field measurement of DO, BOD, pH, EC, Nitrate, Phosphate, and Temperature, in four seasons of the year 2018, in tandem with the river simulation and its calibration using QUAL2Kw model and the Streeter-Phelps method. In addition to the modeling and analysis results, the measured laboratory data values of the river water samples are also presented. Based on the results, the DO variations were ranged from 5.15 in summer to 7.47 mg/l in spring and BOD variations ranged from 1.88 in fall to 7.9 mg/l in summer. Also, according to the Streeter-Phelps method the decay coefficient values varied from 1.57 (1/day) in spring to 9.63 (1/day) in fall. The values of the Talar River decay coefficient also varied from 2 in fall to 7.7 (1/day) in summer involving the QUAL2Kw model.
A.r Modares Nia, M. Mirmohamad Sadeghi, A. Jalalian,
Volume 25, Issue 4 (Winiter 2022)
Abstract
Desertification has become one of the main problems of human societies living in the vicinity of desert areas in recent years. One of the methods that have been considered in recent years and are rapidly expanding in the field of soil mechanics is the Microbial Induced Carbonate Precipitation (MICP). In this method, urea-positive organisms that are naturally present in the soil can stabilize the soil and improve its engineering parameters by using urea and calcium chloride. Recently, attempts have been made to use this method to create a crustal layer on the soil to prevent wind erosion. In the present study, the effect of environmental conditions in deserts such as temperature and sand bombardment on microbial soil treatment has been investigated using this new method. The soil of the Segzi region as one of the main centers of dust in the Isfahan region was studied in this research. Therefore, the improved samples are subjected to regional temperatures which increased the surface layer resistance with increasing temperature. Also, the sandstorm conditions of the region were simulated using three different grain sizes of sand inside the wind tunnel. The results of these experiments showed that stabilized soil could withstand the conditions at wind speeds of 7 and 11 m/s. However, by increasing the wind speed to 14 m/s and the grain size, the crustal layer destroys and increases the wind erosion of the soil. Also, the resistance of the surface layer increased by increasing temperature in the tested samples. This increase in resistance continued up to 24 degrees with a high slope, but from 24 degrees onwards, this slope decreases. Based on the results of this research, it can be said that the microbial improvement method can be used as an alternative method in the future to stabilize desert soils.
S. Ebrahimiyan, M. Nohtani, H. Sadeghi Mazidi, E. Soheili,
Volume 26, Issue 1 (Spring 2022)
Abstract
The basis of land management is the geomorphological zoning of the land surface, which is determined based on the same geomorphological characteristics of the zoning. Ground zoning detect land features by basic surface features such as height, slope, and slope direction. In this study, quantitative zoning of the land surface with small coefficients to the surface has been used to identify suitable areas for artificial feeding in the mountainous region of Gohar and Dasht-e Gorbayegan in Fars province. Quantitative zoning of the land surface has been performed by Evans-Shri coefficients due to the accurate determination and separation of types, faces, and surface features of the land has an important role in determining the exact land use. In this research basic models included linear, circular, and divergent models. These basic models with the dimensions of the final windows are ranked second in the MATLAB software to the level the ground is fitted to determine the fit of these models, the parameter of total squared difference has been used. In addition, the suitability of the study area for flood distribution in five different classes was determined using fuzzy logic. The most suitable areas for feeding downstream of the cones had five parameters with a maximum score of 20. The inappropriate class related to the lower plains of alluvial fans have a minimum score of five input classes in fuzzy logic, which is equal to zero.
M.h. Sadeghi Ravesh,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
The optimal strategy selection is an influential factor to enhance the efficiency of land reclamation projects. On the other hand, the process of desertification of the land during environmental degradation is the consequence of the interaction between various factors that make it challenging to select appropriate solutions. Therefore, this study aimed to provide systematic optimization strategies in the form of a group decision-making model in the Yazd-Khezrabad plain. The important strategies were identified using the Delphi model. Then, the alternative initial ranking was formed by Cook and Seiford method framework using the vote taken from the decision makers on strategies. Finally, by estimating the linear distance of each option and including the matrix of the intervals, the last priority of the strategies was obtained from solving the assignment problem. The results indicated that the strategies of "prevent land use inappropriate change" (A18) and "the regeneration of vegetation cover" (A23) with Value=1 and Reduced Cost=0, were identified as the most important combating-desertification strategies in the region, respectively. The results of this study help desert managers to utilize limited facilities and capital dedicated to controlling the desertification process efficiently and effectively.
M. Sadeghi, T.o. Naeeni, F. Kilanehei, M. Galoie,
Volume 26, Issue 3 (Fall 2022)
Abstract
One of the most important hydraulic structures in a dam is the spillway. The design of the ogee spillway crest is based on the lower profile of the free-flow jet passing through the sharp-crested weir. When the downstream ogee spillway profile for the design discharge conforms to the lower profile of the free-jet passing through the sharp-crested weir, the pressure on that surface of the spillway becomes zero. In this study, the design of the ogee spillway was performed initially based on both two- and three-dimensional numerical modeling and then compared to the USBR standard method. The comparison of the final numerical and analytical results showed that although the vertical two-dimensional outputs were completely in agreement with the USBR standard profile, the three-dimensional profiles were different because in this model, guide walls were not considered. According to the analysis, if the flow entering the spillway is parallel to its axis, the lower profile of the sharp-edge spillway will be in complete agreement with the standard profile. Since, the design of guide wall geometry for ogee spillways is carried out using physical modeling which iteratively revises during a high-cost trial and error procedure, this research based on the case study of the spillway of Karun-3 dam has been tried using numerical modeling. The closest geometry to the geometry of the overflow guide wall was obtained which creates the least difference in transverse velocities. In this way, the design of guide walls can be done with more accuracy and low cost in comparison to physical modeling.
A.r. Eftekhari, M. Mirmohammad Sadeghi, A. Jalalian,
Volume 27, Issue 2 (Summer 2023)
Abstract
The use of biotechnology-based methods in the field of geotechnical engineering has led to the birth of new knowledge of biogeotechnology and several studies have been conducted using this new knowledge in various geotechnical issues including reducing permeability and increasing shear strength, especially in sandy soils and the desired results have been obtained. Nevertheless, little research has been done using biogeotechnology in the field of improving the mechanical properties of clay soils, especially in reducing the swelling of expansive soils, which is considered one of the types of problematic soils. The main cause of swelling of expansive soils is the presence of montmorillonite clays in these types of soils. Using chemical additives to stabilize expansive soils such as lime and cement is a common practice. However, environmental concerns related to greenhouse gas production caused by the production of chemical substances and the destructive effects of these substances on the environment and soils have encouraged researchers to use other sustainable stabilization alternatives. Microbial Induced Carbonate Precipitation (MICP) is a technique that can be a promising solution to solve this problem. The objective of the present study was to investigate the effect of the MICP method on the swelling of expansive clay soils and its effect on the mechanical strength of this type of soil. One-dimensional swelling tests, uniaxial compressive strength tests, and Atterberg limits tests were performed on clay soil with a liquid limit of 53 using Sporosarcina pasteurii bacteria, calcium chloride, and urea as nutrients. Taguchi's method was used for the design of the experiments and the statistical analysis of the results. This method designs experiments through partial factorial and reduces their number without a significant effect on the results. Bacterial concentration, nutrient molarity ratio, treatment time, and soil moisture were selected as four factors with Four levels of variation. The results showed that the (MICP) method was effective in reducing the swelling potential of expansive soils and also caused a significant increase in the unconfined compressive strength of the soil and its undrained shear strength.
A. Shahnazari, S. Sadeghi,
Volume 27, Issue 2 (Summer 2023)
Abstract
In the present paper, crop pattern criteria have been evaluated relying on sustainable development to increase agricultural water productivity. Seven criteria were selected as the main environmental and economic criteria and were prioritized and reviewed for important and strategic products in the Tajan catchment of Mazandaran province. Criteria prioritization was done using optimization through a genetic algorithm with an objective function based on sustainable development. Then, physical and economic productivity indices were calculated to determine the productivity value. Based on the results, in the selection of the crop pattern, firstly, the category of economic criteria and finally the category of environmental criteria have been given attention to the farmers in the current situation. But in the genetic optimization algorithm, all priorities have a similar order from the environmental point of view and then from the economic point of view although each product has its order of criteria. By this prioritization, the parameters of the cultivated area, the volume of water consumed, and the amount of chemical fertilizers have decreased on average by 26%, 34%, and 21%, respectively, and the parameters of product performance and profitability have increased by 43% and 61%, respectively. In addition to providing environmental standards and increasing sustainable development, this prioritization causes an average increase in physical productivity by 84% and an increase in economic productivity by 72%.
