Journal of Water and Soil Conservation
Year:2019 | Volume:26 | Issue:2 |Papers Count:15

Background and Objectives: The numerical modeling of the immiscible flows in the porous media is one of the issues which have always been considered by researchers due to their application in the monitoring of the groundwater pollutions, water and oil behavior in the petroleum reservoirs and hydrology sciences. In this study, we present a two-dimensional discontinuous Galerkin numerical model of immiscible flows in a porous media using the high order implicit pressure-explicit saturation (IMPES) strategy for governing equations. Here, the primary unknowns are wetting phase-pressure and saturation. In this hybrid numerical scheme, for the first time we developed the second-order Lax-Wendroff method to solve the water saturation equation which is considered as the main novelty of this paper. Materials and Methods: For the numerical modeling of immiscible groundwater pollutions, it has been utilized the local conservative discontinuous Galerkin scheme as the spatial discretization. The backward Euler and second-order Lax-Wendroff scheme are applied as temporal discretization for pressure and saturation equations respectively. Also, we stabilized the exchanging numerical flux and used projection of the velocity field in the H (div) vectorial interpolation space for improvement of results at the heterogeneities. at the end of each time step, non-physical oscillations omitted using modified Chaven-Jaffre slope limiter and the results are stabilized. Results: The second-order Lax-Wendroff scheme based on the Taylor expansion and the high order time derivatives is comparable with conventional IMPES strategy schemes such as multi stage Runge-kutta Method (RKDG) while has less computation cost than multi stage schemes. However, the time step size and the Courant number have some restrictions with respect to the explicit solving of the saturation equation. Conclusion: In order to validation of the model, the Buckley-Leverett benchmark problem is considered. The results of the developed model are compared with of other authors and a good agreement is observed between them. Also, model efficiency and ability have been evaluated with two test cases for high heterogeneous aquifers. Also employing various techniques improved the discontinuities resolution in highly heterogeneous media. Numerical models showed good nonoscillatory resolution of saturation around the less permeable subdomains and frontal interface between the wetting and nonwetting phases. In this study, the penalty parameter varies between 50 and 100. In SWIP version of DG method, the penalty parameter should be chosen greater than 50 while in OBB-DG method zero values could be allocated. The sensitivity analysis of the model has been considered for various effective parameters in modeling.

Background and Objectives: Nowadays water scarcity has become one of the most important problems in many communities. Construction of dams and water storage to provide part of the required water and flood control is one of the ways to coexist with problems caused by water scarcity, flood or drought. Evaporation of lakes, reservoirs and ponds surfaces in the optimal utilization of water resources. Evaporation rates from surface waters are usually higher in wet areas, especially in areas where the horizontal flow of heat transfer is significant. On the other hand, the amount of sedimentation in the reservoir of the dam increases over time. One of the problems of sedimentation is changes in the geometry of the reservoir and the increase of the dam lake level for different amounts storage volume. This, in turn, leads to increased evaporation due to an increase in the levels of Lake dam. Therefore, the main objective of this study is to estimate the evaporation from the lake level of the Kardeh dam and to select the most suitable method for estimating evaporation from the lake surface and also to determine the effect of sedimentation on evaporation from the reservoir level. Materials and Methods: In order to estimate the rate of evaporation from the Kardeh reservoir, first by using 6 thermal evaporation method including Jensen-Haise, Hamon, Estefen-Stewart, Papadakis, Abtew and Turc the evaporation rate was estimated in monthly, quarterly and annual scales. Then, these values were compared with data from pan evaporation, using nine indicators evaluate errors. Also, to determine the impact of sedimentation on the evaporation of the lake of this dam, reservoir levels per amount of storage volume (5 scenario includes volumes 5, 10, 15, 20 and 25 million cubic meters) was determined according to the Hydrographs that was conducted in the years 1375-1376, 1382-1383 and 1387-1388. Results: The results show that Jensen-Haise method, is the best thermal method of estimating evaporation in terms of lack of pan evaporation measured data. It should be noted that in order to estimate the evaporation in monthly or seasonally scale, Papadakis method for winter and Turc method for the summer season will be appropriate methods. Also, by reducing profitable volume due to sedimentation, reservoir lake level (per amount of stored stream) increases. So that this increased level by increasing the storage volume from 5 million cubic meters to 25 million cubic meters, evaporation rate increase to three times the first case. In other words, it can be stated that with 5 times the volume stored in the reservoir (storage volume change from 5 to 25 million cubic meters) and also increase sedimentation the volume of surface evaporation 3 times increases. Studies show that all methods whether overestimated or underestimated, show increasing evaporation rate by changing the storage volume during the mentioned years due to the increase of the level of the lake of Kardeh reservoir. Conclusion: Jensen-Haise due to the closest data with pan evaporation data and earn the most points from the total score of 9 evaluation index error in estimating evaporation, were selected as the best thermal method for estimating evaporation in terms of the lack of pan evaporation measured data in the region among the six studied methods. Hamon estimation of evaporation method is the most underestimated and Etefen-Stewart method is the most overestimated method. Increasing sedimentation in the reservoir improves the water level to higher level in the reservoir, which, in view of the open geometry of the reservoir of Kardeh dam, will lead to an increase in the lake level and ultimately increase the evaporation rate from the reservoir's dam.

Background and Objectives: Rivers are delivery vehicles of soluble compounds and sediments eroded from upper reach to wetlands and lakes. Therefore, evaluation of weathering intensity opens new insight into upland erosion, anthropogenic and geochemical process. Weathering indices CIA and WIP have been extensively used for the study of soil genesis. Nonetheless, little information available on the weathering indices in Iran's soil and sediments. Therefore, this study was conducted on sediments of seven main rivers of Urmia Lake basin with objective of evaluation of two weathering indices and influence of particle size distribution on the weathering process. Materials and Methods: In this study 34 composite sediment samples have been taken from seven main western rivers of Urmia Lake basin including: Nazloo Chai, Shahar Chai, Barandooz Chai, Ghadar Chai, Mahabad Chai, Simineh Chai and Zola Chai. The physical and chemical properties of sediment were determined with routine soil testing methods. Elemental analyses of sediment samples were determined using an X-ray fluorescence (XRF) spectrometry. Major element oxides were measured by using a built-in program SUPERQ. Then the CIA and WIP indices were calculated. The analysis of data was carried out using correlation, principal component analysis (PCA) and cluster analysis. Results: The major oxides in the studied sediments were silica, aluminum and calcium. The ratio of silica oxide (SiO2) to upper continental crust (UCC) for all the samples were less than 1 and varied between 0. 57 and 0. 84 indicating no dilution effect in the mineral transportation. Based on the major oxides component, the similarity among the different rivers was more than 65 and only in the Ghadar and Barandooz rivers the similarity is low because of the presence of MaO. The content of CaO had inverse significant correlation with SiO2, Al2O3 and Fe2O3 (with correlation coefficient between-0. 62 to-0. 67, P<0. 001). The CIA and WIP values were varied between 50. 1 to 82. 6 and 42. 4 to 66. 2, respectively. Both indices had normal distribution, but WIP index had higher correlation coefficient with particle size distribution particularly D50 (r=-0. 84, P<0. 001). The CIA index showed lower significant correlation with D50 in comparison with WIP. Conclusion: High concentration of CaO and MgO in the river sediments may be due to the presence of calcareous rocks such as limestone, dolomite and calcareous shales in the watersheds. High SiO2 and Al2O3 concentration in river sediments may draw a conclusion that lower silica weathering and enrichment of potassium feldspar in river sediments. High loading value of in the river sediments may be due to the presence of calcareous rocks such as limestone, dolomite and calcareous shales in the watersheds. Overall, the CIA and WIP weathering intensity values in upper and lower reach sediments revealed high difference. However, in some rivers such as Mahabad Chai because of construction of dam for more than half century the pattern of weathering intensity was different. Based on the A-CN-K curve. The studied river sediment indicate weathering trend in parallel with the A-CN line, indicating the elimination of silicate minerals of Ca and Na from parent material. Weathering indices in particular WIP had higher correlation coefficient with particle size distribution and D50 and we can conclude a proper index for evaluation of weathering intensity in the sediments.

Background and Objectives: The grass is one of the plants that is used widely in the landscape of industrial centers. This plant has a high water requirement. So, because of low precipitations in recent years, some medicinal plants are used as a plant in landscape, because, these plants not only resist to adverse environmental conditions, but also have low water requirement, nutrition and low maintenance cost compared to grass. However, in each region their adaptation and yield depends on various factors such as climatic conditions, physical and chemical conditions of the soil, water quality, irrigation intervals and type of plant. For this reason, the present study was designed to evaluate the compatibility of Salvia sahendica to water stress and determining the appropriate irrigation regime for its application as landscapes in industrial centers. Materials and Methods: This experiment was conducted at the research farm of Isfahan Mobarakeh Steel Company. After field preparation, the research treatments including five irrigation interval (2 (control), 4, 8, 12 and 16 days) as the main factor and two plant including grass and Salvia sahendica as subsidary factors was carried out in a Split plot design with randomized complete block design with 2 × 2 meters plotted in 3 replications in 1395. After the establishment of plants, the water stress was applied by irrigation intervals. At the end of the summer, the plants (leaf, root and whole plant) were harvested and plant growth factors were measured in three replications. The means comparison conducted by LSD method using MSTAT-C software. Results: The results of analysis of variance showed that the effects of irrigation interval, species and their interaction were statistically significant at 1% on all morphological and physiological traits. Based on the results of the means comparison, by increasing the irrigation interval from 2 to 4, 8 and 16 days, a significant reduction in the studied traits were observed in the grass (P<0. 05). while, the lowest percentage of viability (5%), surface coverage (5%), visual scoring (10%), leaf area index (4%), relative water content of leaves (9%) and chlorophyll index (3%) was observed in the 16-day interval as compared with control plant, but the reduction of these traits in the Salvia sahendica was not significant to 16 days (P>0. 05). In this plant, the lowest records of named traits were (60%), (67%), (66%), (80%), (68%) and (59%), respectively in 16 days interval. In the grass, proline content, electrolyte leakage, the ratio of root to shoot dry weight and the root highest length were significantly increased by increasing irrigation intervals to more than 2 days (P<0. 05). These traits increased 4. 7, 4. 2, 2. 3 and 2. 6 times, respectively in the 16-days irrigation interval in this plant. In Salvia sahendica, this parameters was not afftected up to 16-days interval. In 16-days interval, these traits increased by 1. 2, 2, 1. 7 and 1. 9 times, respectively. Conclusion: Considering non-significant (P>0. 05) decreases of the studied parameters of Salvia sahendica up to 12-days interval in comparison with control, it can be concluded that an optimal irrigation regime of this plant in order to use in the landscape is irrigation interval of 12-days. It saves water resources in comparison with grass. According to results, the use of Salvia sahendica is recommended for use as landscape and alternative of grass in the studied area and in other similar areas at confidence level of 95%.

Background and Objectives: Nowadays, water scarcity is one of the current issue in Iran. And this issue more than ever reveals the needs for an appropriate water resources management. Stochastic Dynamic programming (SDP) is one of the extracting methods to obtain the reservoir operation rules. In this method, one of the most important factors to find the optimal solution is discretization of the storage capacity and reservoir inflow. In this research, to achieve optimal storage discretization by SDP method and considering tree types of objective function (α = 0, α = 0. 5, α = 1) with the constant reservoir inflow classes, some storage classes (3, 5, 7 and 10) are analyzed. Materials and Methods: In this study, the SDP model has been used to find the optimal storage of Jamishan reservoir by any objective functions. By having historical reservoir inflow time series and storage volume, reservoir inflow and storage are discretized into 3 classes with equal length intervals method and also 3, 5, 7 and 10 classes with Moran method, respectively. This method is applied by considering objective function as a minimization of system damage for each combination of the reservoir inflow and storage classes (k, i). By achieving the steady policy at each period, the amount of reservoir Inflow, storage and release are deterministically defined. Results: The results showed that in case of α = 0, the optimal storage capacity considering just downstream water supply of demands as an objective function, is k = 7 and there is minimum water deficit. In addition, this would be 10 classes in case of α = 1, which the amount of difference between reservoir storage and its desirable would be changed from constant value and the first decreasing change would be appear. Obtaining reservoir storage classes is also affected by method of discretization since this value is obtained 10 for classic and Moran method with the same result and 7 in Savarenskiy method. That is selected k = 10 based on the equal objective function in case of α = 0. 5 considered two objectives of reservoir release storage volume simultaneously as well. Conclusion: Since the objective function is only reservoir release and water allocation, the optimal reservoir storage class would occur at the point where the water deficit is constant by increasing the number of storage classifications which k = 7 is the optimal class in this case. In the second scenario the best discretized class of the reservoir storage is the point which has the closest vicinity to the target storage (Ts). So, in this case, k = 10 is the optimum reservoir storage. In the third scenario, by choosing k = 10, two goals minimizing the amount of storage and release from the desired values, are well regarded in this case and also the first decreasing changes is happened in k = 10.

Background and Objectives: Management of water resources, especially groundwater, is important in arid and semi-arid regions. One of the important issues in optimum water resources management is the prediction of drought conditions. Groundwater is considered as the main resources of water supply for agriculture, industry and drinking uses in Boroujen plain. Therefore, it is important to investigate the drought condition of groundwater resources in the planning and sustainable management of these resources. So far, various methods have been developed and used by researchers to predict various types of droughts. One of these methods is the prediction of wetness conditions by the Markov chain. In most of the previous studies in the field of drought prediction, the Markov chain of first and second orders have been used. In this study, groundwater droughts in Boroujen Plain during the years 1985 to 2015 are assessed and the wetness conditions of this plain are predicted using the third order Markov chain model. Materials and Methods: In order to assess the groundwater droughts in the Borujen Plain, the GRI index values were calculated on the time scales of 1, 3, 6 and 12 months. For this purpose, the data of groundwater levels of 13 piezometric wells in Boroujen plain during a 31 year period (1985-2015) were used. In order to predict the GRI index values in Broujen plain for the next months, the first, second and third-order Markov chain models were used and the performance of these models was evaluated based on contingency table method. After forming the contingency table from the results of first, second and third-order Markov chain models, the values of CSI, POD and FAR statistics were calculated. The CSI values for Broujen plain in the time scales of 1, 3, 6 and 12 months for the first order Markov chain model were calculated equal to 0. 58, 0. 50, 1. 0 and 1. 0, respectively. The CSI values for the second order Markov chain model in the time scales of 1, 3 and 6 months were obtained equal to. 0. 45, 0. 33 and 1. 0 and for third order Markov chain model equal to 0. 40, 0. 38 and 1. 0, respectively, which indicate the medium skill of the developed method in the prediction of wetness conditions at 1 and 3 months time scales and good skill at 6 months’ time scale. In addition, the delineation maps of GRI index were drawn by selecting the most suitable interpolation method. Results: The delineation map of GRI in the Broujen Plain shows that the middle parts of the plain often experienced severe droughts. Comparing the performance of different orders of Markov chain in predicting the wetness conditions of Boroujen plain based on CSI, POD and FAR statistics showed that first order Markov chain method presented more accurate results than other models in predicting GRI values in all time scales. Therefore, it can be used to predict the groundwater drought in Boroujen Plain. Conclusion: The results of the GRI survey for Boroujen plain showed that during the period under study, the drought spell of groundwater began in 2008. In general, the severe droughts that have occurred in recent years due to reduced atmospheric precipitation, along with the overexploitation of groundwater have caused the severe decline in groundwater levels, which leads to degradation of groundwater quality and land subsidence in the Boroujen plain.

Background and Objectives: To pass the excess water and floodwaters from upstream to downstream of the dams, a structure called "spillway" is used. This structure is vital and integral as they should be ready for operation at any time. Stepped spillways are introduced as a viable option for improvement of spillways facing problem when flowing the possible maximum flow rate. Stepped spillways consist of stairs which start near the crest and continue to lower heels. Increase of roughness leads to a uniform and continuous distribution energy of the flow over the spillway. This is of great benefit for designers as is no need to create a power reduction plant such as a relaxing pool (where energy should be dispersed at once), or in the case of need the dimensions of these structures will be reduced. Materials and Methods: In this study, to increase the roughness on the stepped spillway, barriers are used to increase the energy dissipation. For experimental tests, a flume with a 90 degree bend was used in Islamic Azad University of Ahvaz (IAU-A). y selecting different models of barriers on the stepped spillway in three forms with three different lengths and widths and also using barriers individually and in combination with 5 different flow rates, A total of 140 tests were conducted. After analyzing the results, it was found that the stepped spillway combined with respectively, triangular, rectangular and trapezoidal, reduced the depreciation and energy loss. Results: Triangular barriers, on average, increase the energy consumption by 15. 9%, rectangular barriers, on the average, increase the energy consumption by 13. 7% and tipping barriers by an average 11. 2% increase in energy depreciation compared to the control model. An increase in the length and width of the barriers results in an increase in dissipation and energy loss. The two-step barriers have the highest energy dissipation and loss. By combining barriers on the two-stair stepped spillway, there is an average of 14. 4 percent increase in energy dissipation. Based on the observations, rise in the Froude number from 0. 32 to 1. 71 led to a decrease in dissipation and energy losses that is due to the immersion of the stairs below the water level and the reduction of the roughness of the stairs and with the increase of the intensity of the inflow phenomenon. The simulation results with the Flow-3D math model are close to the physical model and on average only 6. 3% of errors are acceptable. Conclusion: After analyzing the results, it was found that in the combination of stepped spillway with triangular, rectangular and trapezoidal obstacles, decrease in energy depreciation and energy loss are noticable. Also, comparing the simulation results and the physical model shows that the Flow-3D mathematical model find less bias with the physical model and closer to reality.

and Objectives: Agro-industrial wastes of olive mill processing are an important environmental problem in olive-oil producing countries. The incorporation of organic wastes such as solid olive waste into soil can be useful for improving soil condition. Phosphorus is an essential nutrient for plant growth. Concurrently, it is also known that phosphate-solubilizing bacteria (PSB) are important for P-solubilization from insoluble phosphorus compounds due to large volume of solid waste generated in olive oil mill processing, especially in Guilan province and increasing demand for phosphorus fertilizers in agriculture, this study was conducted with the aim of increasing the available phosphorus from solid olive waste in the presence of Pseudomonas solubilizing phosphorus bacteria in calcareous soil. Materials and Methods: Solid waste obtained from an olive oil mill (Rudbar, Guilan province) and loamy soil employed in this study was collected of Lowshan from the topsoil (0-30 cm). Native pseudomonas with the ability of phosphorus solubilizing was isolated in Sperber medium plate containing insoluble phosphorus and then phosphorus solubilizing index (PSI) was calculated. The treatments for soil incubation consisted of three levels of solid waste include 0 (W0), 2 (W2) and 4 (W4) percent and three levels of bacteria, without bacteria (Pn), isolated pseudomonas (Pi) and pseudomonads CHA0 (Pch) as an index bacteria in 11 sampling times. Soil samples were thoroughly mixed with solid wastes and after inoculating with bacteria (106 cell/g) were incubated at 28 ° C in 70% of the WHC. Sampling was carried out at 0, 2, 7, 14, 28, 42, 56, 86, 116, 146 and 176 days of incubation. pH, organic carbon, microbial basal respiration, microbial biomass carbon, available phosphorus and phosphatase activity were measured. A multi-level factorial experiment with complete randomized design was employed in three replications. Mean comparisons were done by Duncan method at P≤ 0. 05. Data analysis was carried out on SAS. Results: The effect of solid waste (W), bacteria (B) and time (T) and their interaction effects on soil studied properties were significantly difference (P≤ 0. 01). Results of the mean comparison of the effect of the different levels of waste and bacteria interaction showed that pH decreased with increasing the amount of solid waste and bacteria activity. The most basal respiration was observed in W4Pcha treatment. With increasing the levels of solid waste, the amount of organic carbon also increased and in W4Pcha treatment reached to 3. 1%. The maximum amount of microbial biomass carbon was observed in treatments that received solid waste. The maximum amount of available phosphorus was observed in W4Pi (99. 1 mg kg-1) and the minimum amount was observed in W0Pn. The activity of phosphatase enzyme also increased with increasing the levels of waste in Pi and Pch bacteria. The results of the effect of waste and time interaction showed a rapid but temporary increase in basal respiration in response to waste. Conclusion: Significant changes were observed in basal respiration, biomass carbon and organic carbon in soils that received solid waste compared to control soil. Adding of solid waste with phosphorous solubilizing bacteria increased phosphatase activity (as an indicator of microbial activity and phosphorous mineralization) in soil. The application of bacterial and solid waste treatment is a solution that, in addition improving the biological properties of the soil, can lead to increase availability of phosphorus, reduce the using of phosphate fertilizers use and the sustainable management of this type of solid waste.

Background and Objectives: Salinity and sodimization of soils are two factors of land degradation, especially in arid and semi-arid regions of the world. Iran is also located in an arid and semi-arid region and saline-sodic soils cover large areas of Iran. Considering that saline-sodic soils have poor physical, chemical and biological properties that reduce the absorption of nutrients by plants and eventually decline in their growth and yield. The use of reformers, including organic matter, can often be a suitable solution for improving the fertility of saline-sodic soils. Materials and Methods: In this study, saline-sodic soil was collected from Nazar-Abad area of Karaj and was mixed with three levels of 1, 3 and 5 percent of cow manure, vermicompost and Azolla (as Organic modifier). Then the treatments were incubated for 5 months at 20 ° C temperature and field capacity moisture. The chemical and physical properties of the control soil, fertilizers and some chemical and hydraulic properties of the treatments were evaluated before and after incubation. Results: The electrical conductivity of the control soil was 13. 09 dS/m and its sodium absorption ratio was 23. 02. After incubation period, 5% Azolla and Vermicompost treatment are at the lowest salinity level. pH reductions in treatments were mostly non-significant. The highest range of changes in the sodium absorption ratio was related to 5% cow manure treatments with a significant difference relative to all treatments. Except for saturated moisture content, there was no significant difference in the amount of moisture in a given suction in different treatments. During the incubation period, there is a significant decrease in the total amount of porosity in all treatments. This decrease was significant in mean porosity in all treatments, the most significant decrease was observed in 5% cow manure treatment and however 5% vermicompost treatment had the highest mean porosity. Due to the fact that most of the water available to plants is in the middle pores, the addition of vermicompost fertilizer at 5% level to saline-sodic can provide optimal conditions for plant growth in the soil. Conclusion: After incubation period, salinity and pH reduction and increasing of sodium absorption ratio were observed in most treatments. On the other hand, it reduced the coarse and mean porosity, resulting in a decrease in the saturation hydraulic conductivity in the treatments. According to the findings of this study, Vermicompost fertilizer at the level of 5%, with chemical and hydraulic correction of saline-sodic soil, showed its superiority among these three fertilizers and then the Azolla at the level of 3% is given priority.

Background and Objectives: Potassium (K) plays a vital role in increasing the tobacco (Nicotiana tabacum) yield and controlling important quality parameters of tobacco such as leaf combustibility. The forms of soil K are soluble, exchangeable, non-exchangeable and structural K. Plant availability of soil K is controlled by dynamic interactions among its different K pools in soil that understanding of these dynamics leads to management of soil fertility. Quantity-Intensity (Q/I) curves of potassium and Q/I parameters provide general information about soil K availability and fertilizers management. This investigation was conducted to study the K forms status and its relationship with Q/I parameters in tobacco cultivated soil in the northwest of Iran. Materials and Methods: Soil samples were taken from 30 tobacco-growing soils in north-west of Iran. Sorption isotherm was constructed in the laboratory by equilibrating and shaking 2. 5 g soil with 25 ml of 0. 01 M CaCl2 containing 0-200 mg K L-1 for 24 h. Potassium Quantity-Intensity (Q/I) parameters such as K buffering capacity (PBCK), K activity ratio at equilibrium (ARe K), energy of exchange (EK), readily exchangeable K (Δ K0) and specific K sites (Kx) were calculated from Q/I curves. The soluble, exchangeable, non-exchangeable and structural K forms in 30 soil samples were measured. Soil potassium forms relationships with each other, Q/I parameters and soil physical and chemical characteristics were investigated. Results: The mean of soluble, exchangeable, non-exchangeable and structural K forms in soil samples were 23 (ranged from 10 to 118), 207 (ranged from 64 to 511), 569 (ranged from 443 to 690) mg kg-1, respectively. There were significant correlations among K forms except for solution K. The clay values had a significant and positive correlation with each of K forms except solution K values. The means of PBCK, ARe K, Δ K0 and KX values were 10. 2 cmol kg-1/(mol L-1)0. 5, 0. 00476 (mol L-1)0. 5, 0. 032 and 0. 46 cmol kg-1, respectively. The EK values for the check treatments ranged from-5151 to-2128 cal mol-1. The relationship of Kso with exchangeable K was positive (r = 0. 42*), but its relationship with pH (r =-0. 37*) and CCE (r = 0. 41*) was significantly negative. Conclusion: There was a significant correlation between solution K and exchangeable K values as well as between exchangeable K and clay values presumably because of exchangeable K depletion in soils that caused to decrease K concentration on tobacco leaf in studied reign. The correlation among exchangeable K, non-exchangeable K and structural K values indicated that a part of the non-exchangeable and structural potassium, could be available for the plant during the growing season. It is necessary that consider soil properties by using quantity-intensity relations for potassium fertilizer recommendation to increase K concentration in tobacco leaf.

Background and Objectives: Desertification relates to the both the process and end state of drylands degradation. This process, with an impact range in more than 100 countries has affected about one billion people in the world and is the result of complex interactions among various factors, such as climate change and human activities. The objective of this study is to forecast effects of climatic and management scenarios on the desertification phenomena in the Jazmourian catchment, located in the Kerman and Sistan and Baluchistan provinces, using system dynamic modeling approach. Materials and Methods: Required information and basic data were collected and desertification factors were identified based on previous research and field observations. In the next step, reference diagrams were created to present the causal relationships and feedback based on which the conceptual model for the desertification of the Jazmourian catchment has been developed. The conceptual model was then converted into a model of stocks and flows and run in the Vensim software environment. Verification of the Model was carried out through behavior reproduction tests. Different scenarios of vegetation management and climate were simulated and the outputs of each scenario were compared to the outputs of existing condition. Results: Based on the results, soil criteria, with a score of 1. 73, is the most effective factor for land sensitivity to desertification in the Jazmourian catchment. Desertification Sensitivity Index was in critical class with a score of 1. 37. The results of scenario analyses for a 30-year period showed that, change in policy and management (1), management of land cover (1. 18 and 1. 25) and climate change (1. 25) are the preferred scenarios for decreasing the Desertification Sensitivity Index. Conclusion: Based on the evaluations and studies, the average weight of the desertification intensity for the current state of desertification based on four factors was 1. 37. By comparing this value with the ESAs, desertification intensity class for the entire area is estimated between the fragile and critical (a). Examining the results of implementing the cover management scenarios is observed that if 10 and 20 percent change in vegetation cover and protection against erosion occurs, the sensitivity index after 30 years will reach about 1. 25 and 1. 18, respectively, which shows the importance of managing coverage to combat desertification, especially in the watershed Jazmourian. Also, management actions in the study area can stop the desertification process and improve the current situation. The research indicates that the system dynamic approach, as one of the integrating approaches for the assessment of desertification sensitivity in the Jazmourian catchment, is a useful and efficient approach which helps stakeholders enhance their understanding of the causal relationships and feedback in the system.

Background and Objectives: In the soil science, echangble sodium percentage and sodium adsorption ratio are two different criteria to evaluate of soil alkality. For measured of ESP, it is essential to have soil Cation Exchange Capacity (CEC). But, CEC determined by using laborious method is expensive and time consuming. Developing a model that predicts ESP indirectly from a easily-measured properties to be more appropriate and economical. Researches showed a relationship between ESP and SAR. So, SAR can be allocated to predict of ESP. For this reason, many attempts have been made to predict ESP from soil. The specific goal of the research develop model to determining ESP based on SAR by OLS and BN models for Bonab soils in East Azarbaijan province, Iran. Materials and Methods: For arrived presented research, 209 soil samples were taken by grid survey (250×250) of Bonab, Iran. The site is located at mean 1300 m above mean sea level, in semiarid climate in the Northwest of Iran. Then, some soil chemical properties such as Sodium, calcium, magnesium, SAR and ESP of the soil samples were measured using laboratory experiments. Then, two model was developed by OLS and BN. OLS estimators are linear functions of the values of the dependent variable which are linearly combined using weights that are a non-linear function of the values of the explanatory variables. So the OLS estimator is respect to how it uses the values of the dependent variable only and irrespective of how it uses the values of the explanatory. So A Bayesian network is a probabilistic graphical model that represents a set of variables and their conditional dependencies via a directed acyclic graph (DAG). Given symptoms, the network can be used to compute the probabilities of the presence of various diseases. Efficient algorithms can perform inference and learning in Bayesian networks. Generalizations of Bayesian networks that can represent and solve decision problems under uncertainty. Results: The Coefficient of Determination (R2) and Root Mean Square error (RMSE) of the soil ESP-SAR model is reported 0. 99, 0. 71 and 0. 98, 1. 63 by OLS and BN respectively. Based on the statistical result, both of soil ESP-SAR model was judged acceptable. T-test were used to compare the soil ESP values predicted using the soil ESP-SAR model with the soil ESP values measured by laboratory tests. The paired samples t-test results indicated that the difference between the soil ESP values predicted by the model and measured by laboratory tests were not statistically significant (P>0. 05). Therefore, the soil ESP-SAR model can provide an easy, economic and brief methodology to estimate soil ESP. The GMER index also indicated low estimation of two selected land evaluation method. Conclusion: The results of present study illustrated that OLS and BN models can predict ESP with acceptable limits. OLS and BN are mathematical models between input and output variables and have the ability of modeling between ESP and SAR.

Background and Objectives: Optimal utilization of water resources systems and appropriate formulation rules and policies for the exploitation of reservoirs have been considered by water resource experts in recent years and extensive research has been carried out. Although much progress has been made in terms of problem-solving strategies and computational tools, the problem of optimizing the operation of a multi-reservoir systems due to the effect of upstream storage capacities on downstream inputs, is so complicated. Routine optimization methods due to high constraints, discontinuous space and non-linear nature of water resource management issues are not a good tool for solving such problems. For this reason, the metaheuristic optimization algorithms have been considered by researchers. Materials and Methods: In this research, the performance of the GA and PSO in solving the problem of optimizing the operation of a multi-reservoir system including Bostan and Golestan dams located in Gorgan-Rood watershed has been studied and compared. The survey of the input to the two dam reservoirs in the year 2014-2015 shows that due to the climate change, the annual input to the Bostan and Golestan dams has decreased by 17% and 60%, respectively. Genetic algorithm is a parallel and guided search based on the theory of evolution. The operators of the GA algorithm include selection, crossover and mutation that are used to make up the next generation, respectively. In PSO optimization algorithm, based on the birds and fishes movements, a number of particles are propagated in the search space and the value of the objective function is calculated in proportion to the position of each particle. Then the new particle position is calculated using the combination of current particle locations and the best place previously used. Results: The best answer of the PSO algorithm during the 10 runs is 909. 95 and the worst is equal to 930. 53, while the best answer of the GA algorithm during the 10 runs is 931. 17 and the worst was 957. 32. The comparison of the mean of the answers also show that the PSO algorithm has a 3% advantage over GA. Conclusion: The PSO algorithm has a better performance than GA, so that the PSO algorithm with a reliability of 49. 38% has a better performance than the GA algorithm with a reliability of 48. 44%.

Background and Objective: Nowadays, use of models to illustrate the facts and better understanding them, as well as make accurate decisions about phenomena is very common. One of these models is the groundwater flow simulation model used by experts in many countries and the accuracy and accuracy of their results have been proven. The object of this study is to evaluate the effect of current management plans of aquifer and Jajrood River basin on changes of the water table of unconfined aquifer and piezometric level of confined aquifer by numerical simulation. Using numerical models, it can be predicted that with the governing process or different management scenarios, how the aquifer reacts to abstraction and recharge. Materials and Methods: In this study, hydraulic behavior of Varamin Plain aquifer was simulated using the Modflow code in GMS software in stable and unstable states. After calibrating the model, hydrodynamic coefficients were corrected, then using the resulted model, quantitative behavior of the aquifer was predicted for two management scenarios in the future years. The first scenario expresses the existing quantitative conditions of the Varamin Aquifer. That is, water do not flow to the plain from southeast wastewater treatment plant of Tehran, but water flows to the Varamin aquifer from Jajrood River. The second scenario indicates situation of the aquifer if the planning are carried out by the relevant organizations. Under this scenario, assigned values from discharging of the southeast wastewater treatment plant of Tehran enter the study area, though due to the implementation of Mamlou storage dam, a significant portion of the surface water resources of Jajrood River will not enter the plain. Results: According to the maps resulted from the first scenario, the groundwater level decline continues as in previous years, but in the second scenario, considering the utilization of wastewater treatment plant discharge, despite the cutting off the water entering from the Jajrood River to the plain, the groundwater decline rate will decrease, although this decline continues. Comparison of the model implementation under first and second scenarios shows that with the implementation of planned projects, part of the aquifer’ s quantitative problems, particularly in the northern areas of the plain, will be decreased, so that in some northern areas the expected decline in groundwater (results of the first scenario) has decreased about 30 to 40 meters by 2041. In the second scenario, the balance of groundwater in the plain is negative, with an annual decline of about 100 million cubic meters of aquifer storage. Conclusion: The results of simulation show that in both scenarios (current trend and after implementation of ongoing plans), the balance of groundwater in the plain is negative and decline in water table will be continued, however in comparison to the first scenario, decline rate of water table under the second scenario will be decreased. It can be stated that in order to stop the decline in water level in Varamin aquifer, in addition to water entering plan from Tehran wastewater treatment plant to Varamin plain, recharge of the aquifer from Jajrood River (as the main source of aquifer natural recharge) should be continued.

Background and Objectives: Increasing the use of chemical fertilizers in order to increase yield can have adverse effects on soil and environment over time. Therefore, reducing the consumption of these fertilizers in sustainable agriculture is necessary. EM contains selected species of microorganisms, including dominant populations of lactic acid bacteria and yeasts, and a small number of photosynthetic bacteria, octanomists that are compatible with each other. These microorganisms improve soil structure, manage organic matter and complete the cycle of elements and can reduce dependence on fertilizers and chemical pesticides. Materials and Methods: This experiment was carried out as split plot based on randomized complete block design with three replications at the University of Mohaghegh Ardabili during the years 2016-2015. Treatments consisted of nitrogen as urea fertilizer at three levels (50, 100 and 150 kg. ha-1 pure nitrogen) and EM bio-fertilizer using two methods of application (foliar and soil with irrigation water) at concentrations of 0, 1, 2 and 3%. Results: According to the results, application of EM fertilizer had a significant and positive effect on all measured traits. 2% EM treatment had a better effect on the absorption of the elements than other treatments. The highest fruit yield was obtained in plants treated with 2% and 3% EM. Plants leaves nitrogen content treated with 150 kg of urea fertilizer was 2. 9% higher than other concentrations. The amount of potassium, phosphorus, zinc and magnesium in leaf and yield of plants treated with 100 kg. ha-1 was higher than other levels of urea fertilizer. Based on the results of the comparison of averages, the application of urea crop 100 kg. ha-1 with EM and 2 and 3% produced the highest amount of Mn in the leaves. Conclusion: Generally, it can be concluded that application of EM bio-fertilizer with both spraying and soil methods can improve plant growth, yield and nutrient uptake by roots of strawberries.