مجله تحقیقات آب و خاک ایران
سال پنجاه و سوم شماره 3 (پیاپی 75، خرداد 1401)

The purpose of this research was to calculate the environmental water requirement and ecological water level of Parishan wetland to transfer water from Nargesi Dam. Based on hydrological information, there is no relationship between the volume of water in the wetland, the amount of rainfall and runoff input. Therefore, the main factor of wetland death is the improper use of water in agriculture in addition to drought. To determine the hydrological water right, the balance formula of lakes was used. Accordingly, the environmental water requirement is 15.05 million cubic meters per year in the case of stop-cultivation plan, and 35.95 in case of limiting 50% of agricultural wells. If the first scenario is implemented, without drought and water transfer after 3.5 years, the groundwater will reach to zero level and then the restoration process will begin, but with the implementation of the second scenario, this time is 5 years and in case of water transfer from the dam, it will be accelerated. Flagship species include Dalmatian pelican, Golden barb and common reed. The year of 2007 was the last year that the entire area had water. Multi Species Indicators (MSI) was 80 and desirable. In 2007, the amount of fishing was 64 tons and it was desirable. The area of ​​reeds in the same year was 220 hectares. Therefore, the minimum ecological level, based on the volume of wetlands in 2007, is 39.3 million cubic meters, but the ecological balance level based on the average volume of wetlands in watery years is 51.6 million cubic meters. Thus, using hydrological and ecological indicators determine the minimum and optimal volume for the restoration of the wetland to its natural functions, and the role of accurate statistics of indicator organisms is very important.

Sugarcane, like all sugar plants, has a high need for potassium. However, the long-term addition of chemical fertilizers to agricultural land degrades the physical and chemical properties of the soil. The aim of present study is to investigate the effect of Vinasse and Humic acid on soil potassium concentration and sugarcane yield to reduce recommended fertilizers in the region. This field study was conducted in 2019 as double split plots in the form of randomized complete blocks. Experimental agents include Vinasse at three levels: 0, 50 and 100 cubic meters per hectare, Humic acid at three levels: 0, 2.5 and 5 kg per hectare and fertilizer treatment of high consumption elements at two levels: recommended and 50% recommended. The results showed that the use of Vinasse and Humic acid had a significant effect on the concentration of all soil potassium forms at a probability level of one percent. The results of simple effects showed that the average of exchangeable and soluble potassium in treatments (100m3 Vinasse), (5kg Humic acid) and (recommended fertilizer) were more than the control by 275, 165, 221% and 692, 371, 484% respectively. The interactions of exchangeable and soluble potassium in the composition (100m3 Vinasse, 5 kg of recommended Humic acid and fertilizer) are 384 and 882% higher than the control, respectively. The results showed the highest and lowest yields in (50m3 Vinasse) and (100m3 Vinasse) treatments at the rate of 61.6 and 28.2 tons per hectare, respectively, and the interactions of the highest yield in (50m3 Vinasse, 5 Kg Humic acid and 50% recommended fertilizer) treatment is 75.2 tons per hectare. The results showed that Vinasse and Humic acid can act well as alternatives to chemical fertilizers and reduce the use of chemical fertilizers with proper management.

Unsustainable development without considering regional planning can create adverse environmental effects, especially in karst water resources of a region from a qualitative point of view. Accordingly, in this study, a combination of two methods for determining spring vulnerability and qualitative zoning by MDHT method was used. This study was performed for three springs downstream of Seymareh Dam for a period of 5 years. The results showed that the value of vulnerability index in S1 spring was higher than the other two springs and the value was 150.4. Analysis of the results showed that the degree of vulnerability was an inverse function of spring discharge. By increasing the amount of discharge, the vulnerability index decreases. Considering the choice of MDHT method for qualitative zoning of the spring and the role of flow rate in determining the zoning scenario, the highest flow rate was related to S3 spring. The value of obtained MDHT index was also higher than the other two sources and the value of 417 has been calculated. The lowest flow rate was related to S1 spring and the MDHT index value was 14.75. The highest level is related to spring S1 and the lowest level is related to springs S2 and S3. The results show that the karst network of springs in the region is vulnerable, which affects the quality of these resources and sensitive areas of the region to develop exploitation are strongly associated with the risk of pollution.

Soil remediation with biochar is a new approach in crop residue management. The aim of this study was to investigate the effect of different amounts of wheat straw biochar in different particle sizes on soil air capacity (AC), macro-pores (PMAC), plant available water (PAW), Dexter index, crop water stress index (CWSI) and wheat yield in a sandy loam soil. A factorial experiment with a randomized complete block design was conducted at the East Azerbaijan Agricultural Research and Education Center (Saeidabad Station) in 2018 and 2019 in three replications. Wheat biochar with amounts of 0.5%, 1.5% and 3% and particle sizes of 0-0.5, 0.5-1 and 1-2 were mixed with soil to a depth of 15 cm. The results showed that the AC was improved by adding ​​0.5% and 1.5% biochar amount and with the particle size of 0-0.5 mm and 0.5-1 mm, respectivilly, compared to the control. The biochar with amount of 3% and the particle size of 0.5-1 mm produced the highest amount of PMAC. In all treatments, the PAW increased significantly compared to the control. Dexter index had a significant increase compared to the control, only in 0.5% and 1.5% amounts ​​with particle sizes of 0-0.5 and 0.5-1 mm respectivily. The change in biochar particle size at 0.5% and 1.5% ​​had no significant effect on dextr index. The lowest CWSI compared to the control observed in biochar amount of 1.5% and particle size of 1-2 mm. In 1.5% and 3% biochar values ​​with 0.5-1 mm particle size and also in 3% biochar values ​​with 0-0.5 mm particle size, the increase in wheat yield was significant compared to the control. The highest significant positive correlation was observed between wheat yield and Dexter index. The results of this study showed that the changes of soil physical properties depend on the amount and particle size  of biochar and it should be considered when using this remediation method.

With increasing population and water consumption in agriculture and industry, the entry of various contaminants into the environment and soil and water resources has been increased. Cadmium heavy metal is known as one of the polluting elements. In addition to toxicity, it has adverse effects on the health of living organisms, too. In this study, the adsorption method was investigated by the three adsorbents of sepiolite clay, corn biochar, and clay and corn biochar complex on the removal of cadmium metal from water. For this purpose, experiments related to adsorption isotherms and adsorption kinetics were performed by the three adsorbents. Parameters affecting the adsorption process include type of adsorbent, change in initial concentration of cadmium solution, and changes in adsorbent contact time were investigated. The adsorption capacity of the adsorbents increased with increasing cadmium concentration from 150 to 800 mg/l, but the adsorption percentage decreased with increasing concentration. The results showed that the highest adsorption capacity in cadmium was related to corn biochar, while the clay-biochar adsorbent had more adsorption capacity than clay adsorbent. Langmuir and Freundlich isotherms for each element and adsorbent were investigated to study the adsorption process. It was found that the adsorption of cadmium by the adsorbents follows both models. Freundlich model with the highest coefficient of determination (R2) and the lowest sum of squares of standard error (SSE) showed the best fit with laboratory data. The effect of adsorbent contact time on the adsorption rate was investigated and found that the adsorption efficiency increased with increasing contact time. Fitting quasi-first-order, quasi-second-order, Elovitch, and intra-particle dispersion models for cadmium at concentrations of 150 and 600 mg/l was performed at 30 to 1440 min. The Elovich model at concentrations of 150 and 600 mg/l cadmium showed the best fit with laboratory data. At concentrations of 150, clay-biochar complexes showed better adsorption performance, but at other concentrations of cadmium, biochar was a better adsorbent than the other two adsorbents. Based on the results inferred from adsorption experiments, it can be stated that the corn biochar compared to clay and biochar and clay and biochar complex compared to clay has a high ability to remove heavy metals from contaminated water, which can be used as a cheap and practical material used to remove contaminants such as cadmium.

Attention to the phenomenon of climate change and its impact on water resources is of great importance. The aim of this study is to evaluate the effect of different methods of weighting the output of AOGCM models and its effect on runoff in Qarahsu Basin during the period 2041-2021. The best climatic models (HADGEM2-ES, MICRO IPSL-CM5A-LR, NOERESM1-M, ESM2M-GFDEL) were selected from 14 general circulation models and weighed with three weighting methods including the same method, Bayesian averaging method and REA method. The results showed that the highest increase of maximum temperature in summer was 1.58 ° C by the same weighting method and the lowest increase of minimum temperature in winter with REA method was 0.96 ° C. The highest percentage of precipitation changes was in August with the same method and the lowest percentage of precipitation changes was in February with REA method. Evaluation of SWAT model simulation results for calibration period using R2 and NS statistical indices in calibration stage is equal to 0.74 and 0.79 and in validation stage is 0.68 and 0.72, respectively, which indicates the accuracy of the model in a runoff simulation. Prediction of runoff changes with the approach of ensemble the output of climate models, shows reduction in runoff in the future period. The lowest and highest percentages of runoff changes will be corresponded to Bayesian method which is -13 and -34.4%, respectively. Overall, the results indicate a change in the temporal distribution of flow in the Qarahsu Basin in the coming period, which will cause significant changes in the quality and quantity of water resources.

Understanding how velocity profile changes in vegetated rivers are important in accurately estimating discharge, shear velocity, and flow resistance. Therefore, in this study, velocity profiles of four direct reaches of mountain rivers with vegetation patches in Fars and Bushehr provinces have been investigated. Data collection in this study started in March 2021 and ended in May 2021. Measurements in this study include surveying, velocity measurement, and bed sampling. Investigation of 71 velocity profiles measured in the selected reaches showed that despite the high aspect ratio () in the studied reaches, in 39% of the profiles, the Dip phenomenon occurred, indicating that the aspect ratio is not the only factor influencing the Dip phenomenon. In addition, The Dip parameter was higher in profiles near to vegetastion pacthes.  Also, by investigating the logarithmic law in velocity profiles, it was found that the logarithmic law is well applicable in reaches with vegetation patches, and the upper limit of the validity of the logarithmic law up to 58% of the flow depth was obtained. This value has been reported in laboratories for velocity data up to 20% of flow depth.

The declining trend of groundwater reserves due to the high importance of these resources for water supply has become a major challenge, especially in arid and semi-arid regions such as many plains of Iran. On the other hand, establishing an urban wastewater project will directly impact the aquifer of the plain and intensify the process of reducing these reserves. This study investigates the effect of revival strategies in the framework of sustainable development principles on improving the aquifer reserves under five different scenarios. The Mashhad aquifer was picked as a case study. Simulation of the aquifer was performed using the system dynamics approach and Vensim PLE model during 1362-1420. Sensitivity analysis and calibration of the model were done during the period of 1362 to 1392, and the model was simulated until 1420 for evaluatation of different scenarios. Sensitivity analysis results demonstrated that aquifer volume has the highest sensitivity to the return coefficient of drinking and agricultural sectors. Increasing the pervious surfaces in urban architecture has improved about 16 and 19 percent in the aquifer recharging compared to scenarios 2 and 3. Generally, using methods such as changing agricultural methods, increasing water productivity, and improving urban architecture with a focus on increasing permeable levels, it can reduce the aquifer shortage between 22.0 % to 58.5%, compared to scenario 2. While not paying attention to the proposed methods led to a negative balance, and the aquifer will be in a critical and irreparable situation.

To choose the right cropping pattern with the aim of maximizing farmer income, stability and stability in production, can not be satisfied only with one-year economic issues, but also issues such as weed control, pest and disease control and soil fertility in the long run should be considered. The method that farmers traditionally use and still is applicabe today, is crop rotation. However, crop rotation is not usually considered in crop pattern optimization. In this study, the effect of crop rotation on crop yield and the amount of profit (as an effective management practice) obtained from the crop unit has been investigated by an evaluation equation. In order to calculate crop rotation as a factor in the optimization equation, an innovative method is presented in this study. In this method, the matrix of crop rotation impact coefficient matrix was completed through the knowledge-base of an expert farmer. The values ​​of this matrix show the coefficients of impact of cultivation of each crop after another crop. Also, to evaluate the effect of rotation, according to farmers, seven different rotations with wheat, potato, corn, barley and fallow crops were studied. The study area is Shavoor irrigation and drainage network in Khuzestan province. The results of the rotation effect showed that in different rotations, the yield of wheat increased by 9.6%, corn by 3.3% and barley by 11.4%, which increases the profit per crop. Also, reviewing superior rotation with other rotations, the results showed that the presence of fallow in rotation and the use of appropriate rotation with selected plants, can increase the profitability of the crop unit.

Bridge piers, which are constructed across the rivers, are always prone to the erosion and scouring phenomena. Bed shear stress is one of the main factors of scouring around bridge piers in which there is a direct relationship between bed shear stress and scouring. In the present research work, firstly the laboratory results of cylindrical bridge piers were used for validation of the model, and then the effect of bridge pier’s shape on bed shear stress and other effective parameters were studied by numerical modeling and applying Flow-3D software. The cylinder pier experienced the highest amount of bed shear stress. In contrast, the case lenticular shape showed 26% reduction with cylinder shape occurs. The results show that different pier shapes have a perceptible effect on reducing the maximum amount of bed shear stress. This function affects streamlines around the bridge piers, and the formation, length, and power of wake and horseshoe vortexes. So that, streams having -0.1m/s behind the cylinder affected the length of 0.2m but in lenticular shape, 40% decrease appears. Additionally, the piers with a forehead causes a stronger down-flow. In those sections, because of the presence of horseshoe vortex, streamlines shift to the upstream, so that the negative velocity figures occur in this region.

One of the practices to improve the agricultural management of paddy fields for sustainable rice production is land equipment, renovation, and integration operations. However, due to some shortcomings, this does not seem to achieve all its goals. Therefore, the purpose of this study was to evaluate the effect of land leveling operations on non-uniformity and severity of changes in soil fertility using fuzzy logic and integrated fertility quality index, in paddy fields of Khosroabad village which is located in fouman city in Guilan province where the land equipment, renovation, and integration operation has been done. In two stages, before and after land leveling operations, 95 and 126 soil samples were prepared from surface horizons, respectively, and then some soil properties related to rice fertility (electrical conductivity, clay, organic carbon, total nitrogen, available phosphorus and available potassium) were measured. In the next step, using fuzzy functions, soil quantitative characteristics were converted into qualitative variables and by using the effect of weight on qualitative variables, the integrated fertility quality index was calculated. The results of measured properties, calculated indices, and the produced maps from them, showed that due to the land leveling operation, the average amount of clay increased (76/9%), and organic carbon, nitrogen, available phosphorus, and available potassium decreased (37, 32%, 41/7 %, and 20/3%, respectively) significantly. One of the main reasons for this is excavation operations and the placement of subsurface soil with more clay and lower concentrations of nutrients in the lower horizon. The integrated fertility quality index also decreased (from an average of 0.31 to 0.18) in most of the studied areas. As a result, it seems that improper implementation of agricultural land equipment, renovation, and integration operations, by reducing the fertility of topsoil, will have long-term negative effects on agricultural land, that elimination of which, will increase the cost of production.

The present study was carried out to model topsoil thickness using machine learning models (MLM) including random forest (RF) and artificial neural network (ANN) in around 60,000 hectares of Qazvin plain lands (intermediate of Abyek and Nazarabad) with an observational density of 278 profiles during 2016 until 2020, and 17 environmental covariates extracted from Landsat 8 satellite images, primary and secondary derivatives from Digital elevation model, climate data, land use and geology maps. Boruta supervised algorithm and expert knowledge were used to select the best relevant environmental covariates. Two functions include "nnet" and "random forest" (RF) by "caret" package in the R software were used. Modeling of topsoil thickness carried out based on 80% of the data in the calibration subset and 20% of the data was used for model validation. The uncertainty of the output maps was quantified using two methods of “bootstrapping and k-fold”. A number of 10 environmental covariates selected among 17 variables, and the relative importance introduced the greenness index, wind effect, diffused radiation, and Mrvbf as the most important covariates, respectively. The validation results indicate that the RF model with R2 of 0.8 and RMSE less than 3 cm and the bias is 0.63 cm in compare to the ANN, With R2, RMSE, and Bias 0.43, 0.05, and.004, respectively was outperform. Also, the CCC for the RF model increased by 50% compared to the ANN. The uncertainty estimated by the bootstrapping method was 7 cm lower compared to k-fold in the regions with 10-15 cm thickness and both of two methods show the same spatial pattern in other parts. The RF model along with selected covariates environmental variables and quantified uncertainties of output maps can be used to model the topsoil thickness and management decision making in areas similar to this study in future studies.

Accurate knowledge of soils and their classification plays a decisive role in the application of various management systems. The purpose of this study is to summarize some of the results of studies in the form of dissertations and articles extracted from them on the factors and processes of soil formation in different climates of Iran during the two last decades performed in different climates of the country in the Department of Soil Science and Engineering, University of Tehran. Variety of soil-forming factors including climate, parent materials, topography, vegetation, and time have led to the emergence of various characteristics and classes based on the Soil Taxonomy system. The predominant morphological traits in the studied soils in each study area, including the existing limitations and advantages, have been determined. In addition to soil classes, morphological, micromorphological, physical, chemical, clay mineralogy, organic and inorganic carbon storage, and geochemistry of formed soils are described in detail. Of the 12 soil categories in the American Classification System, at least 7 categories, and of the 32 reference groups of the WRB System, there are at least 16 reference groups in the study areas. The micromorphological results proved the effect of aeolian sediments on the soils formed on the basalt. Illite and chlorite in the clay mineralogy of many soils of the studied areas indicate that the studied soils are young. Smectite was found in slightly more developed soils (Vertisols and Aridisols). The formation of allophanes from pyroclastic materials is also a proof of the predominance of aluminum over silicon in the early stages of their aeration. Almost all soil-forming processes in this research were studied and discussed, and from an educational and research point of view, a clear view of the country's soils was shown.

Today, the use of chemical fertilizers to increase agricultural production has created many environmental problems. In addition, environmental stresses are one of the most important factors reducing crop yield and production. Given the importance of rice plants in ensuring food security nationally and globally and increasing the price of chemical fertilizers, it is necessary to find eco-friendly routes for sustainable agriculture. The use of biofertilizers is the most worthy way to reduce the use of chemical fertilizers and improve plant resistance in rice fields. Azotobacter has been used as a biofertilizer for over a century and has been well studied on a laboratory and field scale. Azotobacter have also been reported as nitrogen-fixing bacteria in the rhizosphere and roots (endophytically) of rice. In this study, the effect of Azotobacter biofertilizer as a plant growth-promoting rhizobacteria, on rice and the mechanisms of this effect were investigated. The results showed that this bacterium produces phytohormones and stimulants of plant growth and fix atmospheric nitrogen in the rhizosphere and as an endophyte in rice. In addition to nitrogen fixation, this bacterium increases plant growth indices, nutrient uptake, and grain yield of rice by dissolving insoluble phosphates, producing indole acetic acid, hydrogen cyanide, siderophore. Also, the use of Azotobacter inoculant in acute salinity conditions increased the concentration of proline, malondialdehyde, ACC-deaminase enzyme, and some hormones in the plant, which increased the resistance of rice to this stress. Considering the positive effect of using Azotobacter inoculant as a biofertilizer on rice plants and the effect of this bacterium on reducing the consumption of nitrogen fertilizers, preparation of biofertilizers containing native bacteria of Azotobacter and their application in rice fields is recommended.

The Knowledge of assessing the stability of vehicles in floodwater is crucial for conscious flood risk management in urban areas. Cars instability in floodwater is classified in three forms: slipping, floating, and overturning, which causes a lot of financial and human losses. Therefore, it is important to assess the stability of vehicles in floodwater to make decisions to reduce the damage and risks associated with it. Few studies have been conducted to determine the instability threshold of vehicles in floods, most of which focus on parked vehicles. This field of study in Iran is a primitive level and no specific work has been done in this regard so far. In this article, experimental, theoretical, and theoretical- experimental studies conducted in instability threshold of stationary vehicles field are reviewed in two periods of 1960-2000 and 2010-2020. In addition, the criteria set out in the Australian Rainfall and Runoff Guideline is used as the main source for determining the instability threshold. The most important achievement of this research is reviewing most of the researches done to predict the behavior of vehicles in flood events. In addition, the strengths and weaknesses of the researches and presented methods were interpreted and evaluated. Finally, the method which can be used in Iran introduced and offers for starting applied research in this field in the country suggested.