Journal of Water and Soil Conservation
Year:2018 | Volume:25 | Issue:2 |Papers Count:26

Background and Objectives: One of the most important goals of the soil science is to investigate the changes in the earth surface systems in the past and using their patterns to predict environmental changes in the future in order to improve land management. Therefore, this study was conducted on the current Zayandeh‒ rud River’ s pathway in a semi-detailed scale in order to understand the development of alluvial plain of the river. Materials and Methods: Geomorphic surfaces were determined using a stereoscopic interpretation of aerial photos with a scale of 1: 20000 and based on the Zinck’ s hierarchical classification system. Fourty eight profiles were drilled at 1 km/km network, according to the common method of semi-detailed soil studies in a grid survey pattern. Soil classification was finalized in accordance with the Soil Survey Staff. The degree of soil evolution was studied according to Harden's soil development index (PDI) for eight control pedons. Results: According to previous studies, the Zayandeh-e-Rud River during its flow time have had a single pathway three terraces in the Zayandeh-rud plain. The last research showed that the Zayandeh-roud River runs through three separate way over time. In this study, the interpretation of aerial photos and field study cleared that the current pathway of the Zayandeh‒ rud River includes a series of three terraces, which each terrace consists of sub-terraces. Also it was found that Fourty eight profiles in this research were classified in four suborder (including argids, calcids, cambids and orthents) with eight soil families. On the other hands, the calculated PDI values for the control pedons of these eight families also were different. This indicated difference of degree of soil evolution in the current river’ s pathway. Conclusion: Therefore, it can be concluded that the soil of three terraces of the current the Zayandeh‒ rud River’ s way is more diverse than previously reported and this variation indicates the difference in the age of these terraces. Pedologic study also revealed that the soils of the first terrace had the highest PDI and evolution. Presence of argillic and calcic horizons in these profiles confirms this conclusion. On the other hand, the soils in the second terrace also had a lower PDI index and less degree of development than the first terrace and were more developed than third terrace’ s soils. Therefore, it can be stated the current pathway has three independent age terraces with multi-interior terraces. From the results of this study, it can be anticipated that also there are terraces on previous river pathway, which require more research to prove them.

Background and Objectives: Ground waters considered as the main source of future water supply for drinking, irrigation and food production due to global climate changes. At present, aquifers around the world are under pressure to meet the growing demands of water due to population growth. Management of groundwater reserves in a sustainable manner is a major challenge. The goal of groundwater resource assessment is to provide information on the current status of the resource and provide insights about the future availability of groundwater. In recent years, several authors have attempted to assess groundwater potential using different data-driven and knowledge-driven techniques associated with remote sensing (RS) and geographic information system (GIS). The main objective of this research is identification of effective parameters in groundwater recharge and assessment of groundwater potential using data-driven ensembled method in Najaf-Abad aquifer watershed. Materials and Methods: The study area lies between 32° 18′ 06″-32° 50′ 12″ eastern latitude and 50° 52′ 46″-51° 41′ 48″ northern longitude. In this research, six steps implemented to map groundwater potential using ensemble approaches including: 1-preparing groundwater well inventory map and dividing into two sets: training and testing. 2-Building the database. In this step layers of groundwater occurrence factors were prepared using different resources such as field survey and Remote Sensing. All thematic layers converted to raster format to use in further analysis. 3-multicollinearity checking among factors and selection of conditioning factors using tolerance (TOL) and variance inflation factor (VIF) indicators. 4-Computating the relationship between training well locations and groundwater conditioning factors using entropy index model and their classes using evidential belief function model. 5-The groundwater potential mapping and classification into four classes using Natural Break scheme 6-Validation of the results using area under curve (AUC) and seed cell area index (SCAI). Results: The results of the multicollinearity analysis among 21 geo-environmental factors influence on groundwater occurrences used in this study showed that the Tolerance and VIF of 15 variables were ≥ 0. 1 and ≤ 10, respectively. As a result, these parameters were selected for simulation. The computed weights for each factor using index of entropy model, indicated that the most influencing factors on groundwater occurrence in the study area were distance from fault, LU/LC and geology. According to the ensemble model, 45. 26% of the aquifer has a very high potential. The results of validation of models indicated that the AUC for EBF, index of entropy and EBF-index of entropy models were 0. 660, 0. 431 and 0. 899, respectively, indicating higher predictive accuracy of ensemble model. According to the results of the SCAI, the values of this indicator were appropriate for all three models. Conclusion: The main conclusion of this study is that the ensemble approach of EBF-Index of entropy associated with RS and GIS technologies provides a powerful tool for groundwater potential mapping in the study area. The areas covered by very high groundwater potential are 45. 26% of the total area, indicating that the study area has a high groundwater potential. The results of this research can be used for effective management of groundwater resources in the study area.

Background and Objectives: Digital soil data with high spatial resolution and enough accuracy and precision are necessary for management of global challenges such as food security, environment problems. Generally, soil data are available in small scale. Nevertheless, in the last decades, with the advent of soil digital mapping and modeling approaches, it is possible to disaggregate soil map units. The spatial disaggregation of soil map units is a method for modeling the spatial distribution of individual soil classes. During this process, the soil map data from a small scale (coarse resolution) is converted to a large scale (fine resolution). The statistical and data mining methods are used for its implementation. The purpose of this research was to predict the spatial distribution of soil classes by disaggregating the soil map units of a semi detailed soil map using disaggregating and harmonizing soil map units through resampled classification trees algorithm (DSMART method). Materials and Methods: The study area is located in Kermanshah province. The total area of the study was approximately 14083. 9 ha. Soil polygon map include 5 map units and 4 soil subgroups. In this study, elevation, slope, aspect, convexity, direct duration, sediment index, topographic wetness index, valley depth and vertical distance to channel network as covariates produced using DEM 10 m. Grain size index, clay index and NDVI were also calculated using Landsat 7 ETM+ imagery. Geological map at scale of 1: 100, 000 were also used as a qualitative covariate. Then, dsmart method is run as a novel approach for disaggregation soil maps. DSMART samples randomly within the soil map units and uses classification trees (C5. 0 algorithm) to produce probability surface maps of soil class distribution. External validation was performed using 82 profiles. The validation dataset was intersected with the corresponding probability surface maps and validation quantified by overall accuracy, producer’ s accuracy, user’ s accuracy and kappa coefficients. Furthermore, confusion index was calculated between the most probable and second-most-probable soil class. The CI expresses concisely degree of confusion of given soil classes. Results: The most important predictive variables in the tree classification model were Vertical distance to channel network, Elevation, lithology, grain size index and MRVBF. The confusion index close to 1 has a large extent in the study area. It shows that occurrence probability of soil subgroups is near equal in each location in both the most probable soil class and second probable soil class maps. Validation of probability surfaces showed that overall accuracy of the most probable soil class, second probable soil class and third probable soil class are 44%, 28% and 11%, respectively. These results indicated the relatively good performance of dsmart method for generating digital individual soil class map. However, kappa coefficients for first, second and third probable surfaces soil maps were obtained 0. 04, 0. 02,-0. 08, respectively. Low kappa coefficients can be attributed to the actual nature of the data, i. e the dominance of the Typic Calcixerepts subgroup as compared to other subgroups of the soil in the traditional soil map and the dsmart model prediction map and validation data. Conclusion: Dsmart method can predict the probability of occurrence of all soil classes which their distribution is unclear in soil map unit. This provides the opportunity to produced digital soil class maps when legacy soil data and covariate information are available. Such outputs may help to understand the relationship between landscape and soil.

Background and Objectives: Considering the existence of uncertainty in the data of water resource problems, it has become more essential to design a reliable water resource allocation model under uncertainty condition. Due to multi-dimensional nature of optimal water allocation problem, considering multiple conflicting objectives within the optimization models is inevitable. The aim of this study is to provide a quantity-quality optimization model which not only balances the economic and environmental objectives, but also remains robust under uncertainty conditions. Materials and Methods: The nominal model of the study was constructed aimed at maximizing the income of the entire system and minimizing pollution load entered to the river. It was applied to the Dez-Karoon river system as a case study. Considering the uncertainties of river flow and water demands, the nominal model was promoted to a robust multi-objective optimization model using the Bertsimas and Sim's approach. The sensitivity of the robust model to changes in uncertainty levels and the probability of constraint violation was investigated. The ɛ-constraint method was used to solve the problem and the nominal model was applied to assess the results of the developed model. Among optimal solutions set, Knee point of the Pareto front was chosen as the final solution. Results: Results from the application of the developed method for optimal water resource allocation in this case study revealed its efficiency and ability to solve the problem quickly and accurately. Comparison of the optimal solution of knee points showed that hedging the optimization model against uncertainties by considering the uncertainty level and violation probability of 0. 1, requires the decrease in operating the river water from 8301. 5 to 7291. 2 MCM/year and adjustment of the economic income from 1, 636, 808 to 1, 365, 693 million Rial/year in comparison to the nominal model. Under such a condition in which prevents the failure of supplying water under a given level of risk, the pollution load discharged into the river will decrease from 53, 949 to 48, 505 ton/ year. The results indicated that without adding extra complexity into the nominal model, it can be immunized against uncertainties using the robust approach. By determination of the uncertainty level and the probability of constraint violation, the decision maker is able to select the robustness level of the water resource allocation model and therefore, explore tradeoff among the values of the objectives and reliability of the system. Conclution: The results demonstrate the satisfactory, high reliability and flexibility of the proposed robust model. Accordingly, the linear model provided in this study may be used as a user-friendly tool in the decision making process for optimal allocation of water resources.

Background and Objectives: Soils may become polluted with high concentrations of heavy metals both naturally, as a result of proximity to mineral outcrops and ore bodies and anthropogenically, as a result of industrial activities. Lead (Pb), commonly causes soil pollution and considered to be responsible for significant decreases in biological activities in soils. Phytoremediation is an emerging and low cost technology that utilizes plants and associated organisms to remove, transform, or stabilize contaminants located in water, sediments, or soils. Phytostabilization focuses on the formation of a vegetation cover where sequestration (binding and sorption) processes immobilize metals within the plant rhizosphere reducing metal bioavailability. Therefore, the success of phytoremediation depends on the interactions between macro-and microorganisms and plant roots in the rhizosphere. Materials and Methods: The contaminated soil was collected from Bama mining site located in the southwest of Isfahan. After surface-sterilization and germination, maize seeds were transplanted into each plastic pot containing 4 kg of contaminated soil that already autoclaved at 121 oC for 2 h. A completely randomized design with 2×2×2 factorial treatment combinations was used with the following factors: with or without earthworm treatments (Eisenia foetida), with or without arbuscular mycorrhizal (AM) fungal treatments (co-inoculated with Funneliformis mosseae and Septoglomus constrictum) and with or without rhizobacteria (co-inoculated with Bacillus sp. and Bacillus licheniformis). After three months of growth under greenhouse conditions, the corn aerial parts were removed from the soil surface. The shoot and root were individually oven dried, weighed and milled to determine Pb concentration. Concentration of Pb in roots and shoots were measured by dry ash method and soil Pb concentration was determined with DTPA-TEA method. Bioaccumulation (BF) and translocation (TF) and remediation (RF) factors for each treatment were calculated. Results: In general, inoculation of these organisms increased plant growth, availability of Pb in soil, plant Pb concentration and bioaccumulation factor. The highest shoot dry weight was observed in earthworms-AM fungi (EM) and AM fungi-bacteria (MB) co-inoculations with 3. 2 times increase compared to un-inoculated plants. Available Pb in soil in earthworm-AM fungibacteria co-inoculation (EMB) was about 3 times higher than un-inoculated treatments. The highest Pb uptake in maize shoot and root were recorded in EMB. Furthermore, the BF in root maize for all treatments were higher than 1. Although the TF for maize was lower than 1, it was increased above 1 in polluted soil co-inoculated with earthworm and bacteria. However, AM fungi tended to decrease the TF compared to un-inoculated maize. The highest RF (0. 14%) with 23 times in crease compared to un-inoculated was showed in EMB treatment. Conclusions: Despite a substantial increase in Pb concentration in maize, Pb absorption was not high enough to achieve extraction rates which would be necessary for practical use. Furthermore, the amounts of BF, TF and RF in this study demonstrated that maize could useful for Pb phytostabilization. Hence, it appears that the presence of AM fungi (as factor improve phytostabilization) could result in a better plant growth and tolerance against Pb toxicity, when soil is co-inoculated with earthworm and/or bacteria, especially under natural conditions that the presence of these organisms' together, could reduce Pb toxicity and improve maize.

Background and Objectives: Stakeholder analysis is one of the key factors in success of management policies in all fields. This tool represents suitable information about the individuals that are effectively participate in implementation of water management plans. The obtained information from stakeholder analysis can be considered as model input in order to schedule the plans and evaluate success of water resources policies. The use of participatory management methods for application of water management plans investigates the level of cooperation of stakeholders and determine their effects in management plans success. Stakeholder participation is in correlation with stakeholders’ interests and power and consequently their importance. The modeling of stakeholder power and the study of relationship between the other features have recently been considered. The purpose of this study is to represent a framework to accurate and ease stakeholder analysis process in primary studies in water management policies or plans. In this research, a novel model is proposed for simulation of stakeholders’ importance to analyze management policies in the field of water resources management. Materials and Methods: In order to gather primary information and analyze input data for the stakeholder characteristic model, questionnaires and interviews with key stakeholders were used. Key stakeholder groups were chosen using expert choice and analytic hierarchy process. Using previous frameworks of stakeholder analysis, the simulation-calibration framework of stakeholder characteristics model was performed. Genetic algorithm was used to calibrate the stakeholder characteristic model as well as estimation of the model parameters. Then, stakeholder’ s power and importance were evaluated using stakeholder characteristic modeling and calibration to compare its result with other stakeholder analysis frameworks. Results: The results of knowledge analysis showed that training stakeholders such as media and other groups should have more knowledge of water resources in the region. On the other hand, the low awareness of politicians who play an important role in water resources supply in the region, is of concern. Some stakeholders of politicians and managers has a considerable level of position in the region that makes them the most effective individuals. According to the importance analysis, politicians and managers are the most powerful and domestic users are least important users in the region. Also, it is observed that the model is able to simulate the importance of stakeholders in an acceptable level with mean absolute error of 0. 487. The results showed that there is correlations between knowledge level, resources, leadership, power and importance of stakeholders. One of the results of this study is that the hidden interactions between the stakeholders were defined using stakeholder analysis framework. Conclusion: This research was done to help managers and decision makers of Qazvin irrigation network to observe consequences of powerful stakeholder’ s effect on excessive water withdrawals. The main conclusion of the research was that performing positive view points about water resources conservation and decreasing opposite groups of stakeholders by creating local benefits in the region can empower the supportive groups of stakeholders to change the approaches in favor of water resources conservation. It is also concluded that using stakeholder analysis can help to define better the stakeholder relationships and to recognize potential opportunities in management strategies.

Background and Objectives: Soil quality is one of the most important factors to assess soil management. Therefore, recognition of all soil quality properties such as physical, chemical and biological is essential. Forest degradation and land use change affect the changes in soil characteristics and reduce soil quality. Moreover, soil characteristics depend on topographic conditions. The region of Marivan in Kurdistan province is one of the forested areas of Zagros which has been threatened due to population growth and increasing demand for food and some parts are now under crop culture. The aim of this research is assessing the effect of forest degradation and slope position on soil quality and evolution in the west of Kurdistan province. Materials and Methods: Eight soil profiles in different slope position (shoulder, back slope, foot slope and toe slope) of two adjacent hill slope, under land uses of cropland and forest (uniform condition) were dug and described. Moreover, in each land use, three soil samples were taken from depth 0-20 cm in each slope position. Properties of soil texture, bulk density, particle density, fine sand, organic carbon, cation exchange capacity, field capacity moisture, permanent wilting point moisture, electrical conductivity, pH, carbonate calcium equivalent, total nitrogen, available phosphorous, available potash infiltration rate, microbial respiration rate, porosity, available moisture sodium adsorption ratio (SAR) and erodibility were measured and computed. Results: The results showed low slope positions (toe slope and foot slope) had higher contents of clay, organic carbon, available moisture, fine sand, silt, total nitrogen, available phosphorous, available potassium, CEC and microbial respiration rate and lower contents of electrical conductivity, soil erodibility, pH and SAR compared to high slope positions. The soils formed in low slope positions had higher depth and evolution compared to high slope positions. The results also showed two land uses (cropland and forest) in relation to bulk density, porosity, silt, clay, carbonate calcium equivalent, fine sand, pH, organic carbon, total nitrogen, microbial respiration rate, infiltration, soil erodibility and available moisture had significant difference and land use change of forest land to cropland has been led to degradation of Mollisols. Therefore, soil properties are dependent to slope position and land use kind and these factors have affected soil properties and evolution. Conclusion: The results showed that forest degradation in the Marivan region led to a decrease in soil quality through a significant reduction of organic carbon, microbial respiration, total nitrogen, CEC, porosity, infiltration and available moisture and significant increasing of bulk density, pH, SAR, fine sand, soil erodibility and silt. Forest degradation and land use change also due to cultivation led to decrease in the organic carbon content and soil structure degradation of Mollic horizon. Therefore, Mollic horizon has converted to Ochric horizon and Entisols and Inceptisols have formed in cropland land use. Moreover, the results showed different slope position affect bulk density, sand, silt, clay, infiltration, erodibility, available water, pH, organic carbon, carbonate calcium equivalent, microbial respiration rate, nitrogen, phosphorous, CEC and potassium and have significant difference. These results showed that the current management of studied land affects the quality of the land and leads to land degradation. Therefore, soil conservation of steep area using prevention of deforestation in Marivan forests and the use of lands according to their capability to conserve soil and land quality is essential.

Background and Objectives: Iran is always encountered with water deficiency and frequent droughts because of locating in the arid and semi-arid regions of the world. In recent years, attention has been paid to the protection of urban water resources, especially green space irrigation. Due to the key role of grass in designing and constructing green space and its high importance in community psychological safety, maintaining the optimal quality of turf grass is essential throughout the year. The current experiment is conducted to provide the amount of subsoil moisture requirement and to stimulate root length growth compared to conventional methods. Materials and Methods: The research was conducted in 2013-2014 in Agriculture Faculty of Tarbiat Modares University, as split plots based on randomized complete block design with nine treatments and three replications. The main factors included sprinkler irrigation (control), subsurface irrigation using buried porous clay capsule and consolidated irrigation and secondary factors included the lack of using superabsorbent, using A200 superabsorbent and acrylamide superabsorbent. Irrigation was carried out on the basis of soil moisture. During the experiment, the changes of soil moisture content, volume of water consumed, turf color, density and root length were measured. Results: The results showed that the changes of soil moisture content was constant and had the same trend in all treatments. In addition, the soil moisture was always between the field capacity (FC) and the management allowed depletion (MAD) and the plant was not under water tension. The results of this experiment showed that the volume of consumed water in sprinkler, consolidated and subsurface irrigation treatments were 7158. 4, 4972. 6 and 4243. 8m3, respectively. In the subsurface and consolidated irrigation treatment, the volume of consumed water decreased 41 and 31% respectively, compared to sprinkler irrigation. This reduction trend was observed in the use of superabsorbent, in such a way that the subsurface irrigation treatment along with superabsorbent (with 51% reduction) has shown the least water consumption in irrigation. Irrigation method treatments had a significant effect on the root length. The highest root length was observed for subsurface irrigation (23. 56 cm) and the lowest observed for sprinkler irrigation treatment (20. 50 cm) that was significant at 5% level. In addition, increasing superabsorbent increased the root depth which was significant at 1% level. Also, the results showed that the density and color of the treatments were not significant. Conclusion: According to providing water requirement of lawns with buried porous clay capsules irrigation system, this method is recommended as a novel irrigation method to optimize water consumption in urban green space.

Background and Objectives: Soil aggregate stability is an important physical indicator of the soil’ s susceptibility to erosion. Aggregate stability can vary, depending on the aggregate size. Some methods including the dry-sieving, wet-sieving and water-drop test have been commonly used worldwide to evaluate the stability of aggregates. Mean weight diameter of stable aggregates was used for the dry-sieving and wet-siewing method. In the water-drop test, aggregate stability is evaluated using the number of water drops needed for disrupting the aggregates. These indices are only used to evaluate the soil structural stability in aggregate samples of the same size. So, application of these indices may cause some errors in evaluating the soil’ s susceptibility to water erosion processes. Therefore, this study was conducted to develop a proper aggregate stability for different aggregate sizes in view point of interrill erosion in a semi-arid soil sample. Materials and Methods: Four aggregate size classes including < 2, 2-4, 4-8, 8-11 mm were collected from an agricultural soil with texture of clay loam in western Zanjan, north west of Iran. A-600 kg aggregate sample was taken from 0-30 cm surface soil with about 10 m3 in volume for each aggregate sizes by sieving the aggregates in the field. The aggregate samples were packed to the erosion plots with 120 cm × 130 cm in dimensions installed in a 9% uniform slope. A total of twelve plots were investigated using the randomized complete block design for four aggregate size classes with three replications. The plots were exposed to seven simulated rainfalls with 70 mm h-1 in intensity for 30-min with 7-day interval. Soil loss resulted by interrill erosion from each aggregate size was determined during each rainfall simulation. The stability of each aggregate size against mechanical impact (MWDdry), wetting force (MWDwet) and rainderop impact (WDT) was determined using the dry-sieving, wet-sieving and water-drop test methods for each aggregate size class, respectively. Additionally, the aggregate stability per aggregate mass were computed and defined as MWDwet-m, MWDdry-m and WDTm, respectively. Beside this, other physicochemical properties including particle size distribution, gravel, bulk density, saturated hydraulic conductivity, organic carbon and calcium carbonate were determined using the conventional methods in the lab. Results: Based on the results, significant positive correlations were found between the aggregate size and the stability of aggregates determined using the methods of dry-sieving (r=0. 99), wet-sieving (r=0. 89) and water-drop-test (r=0. 93). The aggregate stability determined using all methods increased with an increase in the aggregate size. Newetheless, evaluating the aggregate stability per aggregate mass indicated that negative correlations existe between the aggregate size and MWDwet-m (r=-0. 95), MWDdry-m, (r=-0. 88) and WDTm (r=-0. 88). Although the coarse aggregates rather than smaller aggregates are resitant against external stresses such as mechanical impacts, wetting force and rainderop impact but their stability per their mass is small. Contrary to our expectation, soil loss by interrill erosion of each aggregate size classes increased with increasing the aggregate stability determined using the dry-sieving, wet-sieving and water-drop-test methods whereas decreased with increasing the aggregate stability on the basis of the aggregate mass. Conclusion: This study revealed that MWDwet, MWDdry and WDT are not the proper indices to evaluate the stability of aggregate size against interrill erosion. The aggregate stability per aggregate mas determined in these methods is a new approch to evaluate the susceptibility of various aggregate sizes of a soil to interrill erosion. Among these indices, MWDwet-m is the best indicator in this field.

Background and Objectives: Rhizosphere processes have a major impact on zinc (Zn) availability in soils. The chemical and biological characteristics of the rhizosphere soils can be very different from those of the bulk soils. In the peresent study, the effects of EDTA, citric acid and poultry manure extract (PME) were investigated on availability of Zn in the rhizosphere of corn (hybrid (KSC. 704)) in two contaminated soils with different texturs. Materials and Methods: This research was done as factoriel in a completely randomized design with three replications in greenhouse condition and citric acid and EDTA were used at concentrations level 0, 0. 5 and 1 mmol kg-1 soil and poultry manure extract at concentrations level 0, 0. 5 and 1 g kg-1 soil to rhizoboxes. Three seeds of corn were plant in the rhizobox and after 10 weeks, plants were harvested and rhizosphere and bulk soils were separated. pH, dissolved organic carbon (DOC), microbial biomass carbon (MBC) and available Zn were determined in the rhizosphere and bulk soils by using four chemical procedures including DTPA-TEA, AB-DTPA, Mehlich3 and rhizosphere-based methods. Results: In both soils, the results indicated that DOC and MBC in the rhizosphere were significantly (P<0. 05) increased, while, pH in the rhizosphere was significantly (P<0. 05) decreased compared to bulk soils. In both soils, Zn extracted by different methods in the rhizosphere were significantly (P<0. 05) lower than those in the bulk soils. The amount of exteracted Zn with extractants ranged from 9. 00 to 75. 00 mg kg-1 in sandy loam soil and 0. 78 to 75. 00 mg kg-1 in clay loam soil. The maximum amount of Zn was exteracted by mehlich3 and the least amount of Zn exteracted by rhizosphere based method. The available Zn increased a long with addition of chelators to soil. Conclusion: The results of this study showed that in sandy loam soil, the maximum amount of Zn was obtained in the citric acid treatment (1 mmol kg-1) and the least amount in control condition, while, in clay loam soil, the maximum amount of Zn was noticed in the EDTA treatment (1 mmol kg-1) and the least amount in the PME treatment (1 g kg-1). The mean of Zn extracted by DTPA-TEA, AB-DTPA, Mehlich3, in clay loam soil was significantly (P<0. 05) higher than those in sandy loam soil. The mean of Zn extracted by rhizosphere-based method in sandy loam soil was significantly (P<0. 05) lower than those in clay loam soil.

Background and Objectives: It is important to study the coefficient of resistance in streams, especially in open channels, canals and rivers. One of the factors influencing the flow resistance is bed-forms. Cluster microforms are types of bed-forms in mountainous rivers, which are important both in biological aspect and in hydraulic of micro-currents (the secondary currents). The study of the recognition and influence of clusters on flow resistance is novel around the world. The purpose of this study is to investigate the effect of cluster shape and particle size on the flow roughness coefficients. Materials and Methods: In order to investigate the effect of the shape and size of the particles that forming clusters, several experiments were carried out in a laboratory channel of 20 meters in length, 0. 6 m in width and 0. 6 m in height. Using gravel particles with three different sizes of 9. 5, 12. 5, 15. 5 mm, three cluster types (linear, heap and rings) were constructed in laboratory flume. Two roughness coefficients namely Darcy-Wiesbach and Manning were calculated using the water surface slope measurements. Results: The results of this study showed that the linear cluster had the least effect on the rate of flow resistance coefficient. The ring and heap clusters have a roughness coefficient greater than the linear cluster, but both have almost same impact on the flow resistance. The results of these two forms of the cluster are very close for particles of 9. 5 and 12. 5 mm, but for a particle of 15. 5 mm, the roughness coefficient of the cluster is higher than that of the other shapes. The manning’ s roughness coefficient is also increases by increasing the diameter of the gravel particles of the cluster builder. By performing experiments with gravel particles of different diameters, the percentage of change in roughness coefficient relative to the non-cluster state for cluster clumps in particles of 9. 5, 12. 5 and 15. 5 mm was 47, 52 and 75, respectively. For rings and particles of 9. 5, 12. 5 and 15. 5 mm, the percentage changes were 48, 49 and 75 percent, respectively and the percentage for linear clusters for particles of 9. 5 and 19 percent and particles 5 / 12 and 15. 5 mm were observed at 37 and 67% respectively, indicating an increase in the flow resistance with an increase in the particle diameter. Also, the results also showed that increase in Froude number reduced the roughness coefficient. Conclusion: The results of the experiments clearly showed that the cluster increases the resistance coefficient through affecting the current. The results of this study revealed that the heap cluster has the most effect on flow resistance.

Background and Objectives: Roads provide access to forest resources for properly management of timber production, transportation, forest protection and ecotourism. Also, one of the main sources of sediment production in forest watersheds. Globally, soil erosion is one of the most important environmental problems which is threaten soil and water resources. Therefore, investigation of soil erosion in the forest roads and determination of their intensity seem necessary. The measurement of soil erosion rates under natural rainfall conditions is costly and time consuming. Data provided by rainfall simulation and static site measurements can be used to predict erosion rates under natural conditions, however the accuracy of this method is largely untested. This is especially true for erosion rates from forest roads. The measurement of soil erosion rates under natural rainfall conditions is costly and time consuming. Data provided by rainfall simulation measurements can be used to predict runoff and erosion rates under natural conditions especially forest roads. The different researchers investigated the factors affecting water erosion in forest roads and studied there is a significant correlation among the amount of soil erosion and slope percentage, vegetation cover percentage, climate, Physical and chemical soil characteristics, road traffic. This study aimed to assess the effect of Vegetation cover on soil erosion, runoff production and sediment. Materials and Methods: The objective of the present study is to investigate the effects of vegetation cover percentage on runoff amount, sediment concentration, soil loss, time to runoff and runoff coefficient on one square meter and with five vegetation cover percentage including 0, <25%, 25-50%, 50-75% and 75-100%, each with four replicates by rainfall simulation at an intensity of 80 mm/h for 15 min and distance 3 min was conducted in Kohmiyan Forest-Azadshahr. Results: The results indicated that the average amount of runoff in level 1 (bare ground), level 2(<25%-), level 3(25-50%), level 4(50-75%) and level 5(75-100) were 24. 7, 17. 82, 12. 78, 5. 23 and 2. 64 l/m2, average amount of sediment concentration were 15. 66, 9. 41, 7. 37, 5. 07 and 2. 39 g/l and average time of runoff were 12. 00, 75. 00, 150. 00, 238. 75 and 365. 75 and runoff coefficient were 47. 8, 35. 62, 25. 71, 10. 58 and 5. 27 percent respectively. The results of analysis of variance showed significant differences between amount of runoff and soil loss due to vegetation cover of road cutslope. The results of Tukey test indicated significant differences among mean runoff and sediment of five level and decrease with increased road cutslope of vegetation cover percentage. Conclusion: The effect of vegetation cover on the cutslope road is completely significant on the amount of runoff, sediment concentration, soil loss, time to runoff and runoff coefficient. In other words, the amount of runoff and soil loss has a reverse and significant relationship with vegetation cover percentage. Vegetation cover percentage has had a positive impact and role in the reduction of the amount of runoff and sediment in the forest roads.

Background and Objectives: Climate Change can affect soil erosion, as the most important factor in the degradation of land in the world, by changing precipitation patterns. Therefore, it is essential to assess the impact of climate change on soil erosion risk. This study was aimed to evaluate the impacts of future climate change on soil erosion risk in Navrood watershed, located in west of Guilan province, North of Iran. Materials and Methods: In this study, the climate change trend was evaluated by XLSTAT software using effective climatic parameters obtained from Rasht and Bandar Anzali stations. Then, the soil erosion risk was predicted using RUSLE in combination with geographic information system and remote sensing, in Navrood watershed. The data of previous research were used to calculate the K, LS, C and P factors for the RUSLE model. The atmospheric general circulation models (NCCCSM), was used to produce synthetic weather series, over three A1B, A2 and B1 scenarios. Based on the outputs of NCCCSM, daily rainfall values of the base period 2002-2007 and the LARS-WG model, daily rainfall pattern were simulated for two 20-year periods of 2046-2065 and 2080-2099 for Kharajgil, Khalian and NAV stations located inside the watershed. Results: The results showed that the precipitation in the future will decrease in two stations of Khalian and Nav and will increase at the Kharjgil station. In contrast, due to increase of rainfall intensity, in all scenarios and stations the rainfall erosivity in the future is more than the base period. Based on the obtained results, soil erosion risk varies from zero to more than 77 tons per hectare per year, from zero to more than 115 tons per hectare per year and from zero to more than 98 ton per hectare per year for the base period (2002-2007) and 2046-2065 and 2080-2099 periods, respectively. Conclusion: The results showed that rainfall erosivity in the coming periods increases due to increasing rainfall intensity. Most area of the watershed has a low erosion risk and the southwest areas of the region and northern parts of the north are mainly at risk of erosion. Additionally, although rainfall erosivity is at its highest level at some parts, the amount of erosion is not high, which can be due to the effect of vegetation. Increasing vegetation density, particularly forest type, can reduce the effect of rainfall erosion and thus reduce the risk of erosion.

Background and Objectives: Since the agriculture field is the main water consumer, using the approaches to increase water use efficiency is necessary. Due to the limited freshwater, farmers have to use exotic water, such as seawater. One of the management methods is the mixture use of freshwater and seawater. The goal of this study was to investigate the effect of different salinity levels on yield and yield components of Quinoa (Cv. Titicaca) in greenhouse condition. Materials and Methods: In this study, the effect of five mixing use of seawater and freshwater evaluated on yield and yield components of Quinoa (CV. Titicaca). The research was done based on completely randomized design including 3 replications as pot planting in Gorgan University of Agricultural Sciences and Natural Resources during 2016. Research Station is located in north of Iran at 36° 51' N latitude and 54° 16' E longitude at the south-east corner of Caspian Sea and its height from sea level is 13. 3 meters. Soil texture is silty clay. In this study, five irrigation regimes included (0, 15, 30, 45 and 60 percent mixture of sea and tap water). The seeds of Quinoa were planted at a depth of 2. 5 centimeter in soil of each pot and were irrigated with tap water. Plants harvested after 6 months, shoot and root dry weight, plant height, yield and thousand kernel weights were measured. Physical and chemical properties of irrigation water and of soil were determined before experiment. The obtained data analyzed using statistical software of SAS (Ver. 9. 0) and the means were compared using LSD test at 5% percent levels. Results: The results showed that effect of different salinity levels on shoot dry weight, plant height, yield and thousand kernel weights was significant at 1 percent level (P<0. 01), but on root dry weight was significant at 5 percent level (P<0. 05). In this study, all of these parameters decreased significantly with increasing water salinity. The result showed that the irrigation regime of 15 percent mixture of seawater and tap water compared to other regimes had the highest root and shoot dry weights, yield and thousand kernel weights after control treatment. While, the 15 percent mixture of seawater and tap water irrigation regime had the highest plant height. Conclusion: The results indicated that increasing of salinity levels from 0 to 15 percent mixture of sea and tap water resulted in redaction of shoot and root dry weight, yield and thousand kernel weights to 9. 8, 9. 9, 2. 2 and 23. 4 percent, respectively. The results showed that this kind of saline and fresh water mixture, in any way, has a high efficiency in reducing salt stress on plant.

Background and Objectives: Accumulation of floating debris around the bridge's piers and abutments reduced the river flow area, flow diversion, flow accelerating and altering of scour pattern. The investigation of potential impacts of debris on the local scour processes is one of the main factors in design of bridge structures across the rivers. These wooden floating debris may have different shapes in terms of accumulation and position, often have rectangular shape in the nature. Although, the effect of debris on piers scour has been studied by different researchers, to the author's knowledge, no investigation has been conducted to study the effect of debris on flow pattern and scour hole characteristics in the case of combinative presence of pier and abutment. Therefore, in this study, the effect of debris with different geometrical characteristics on the pier and abutment scour and flow behavior was investigated experimentally. Materials and Methods: In this study, the effect of distance between bridge pier and abutment, geometrical characteristics of debris (including thickness, diameter and shape) on the scour was investigated experimentally. The experiments were conducted at the hydraulic and water structures laboratory of department of water engineering of Shahid Bahonar university of Kerman. The experimental flume has a rectangular cross section with 8 m length, 80 cm width and 60 cm depth. Model of bridge pier (diameter 3 cm) and bridge abutment (6 cm * 12 cm) was selected by stainless steel. Sedimentary bed with thickness of 16 cm, was composed of sediments with d50=0. 91 mm. To avoid undesirable erosion of sediment, false bottoms were installed at the upstream and downstream parts of the study reach. Prismatic objects with different shapes of rectangular, triangular and semi-circular were used as debris. (The range of relative thickness of debris (􀭘 􀳏 􀭈 ) was from 1 to 3 and the relative length of debris (􀭈 􀳏 􀭈 ) from 4 to 10). The sediment threshold velocity and the maximum velocity of experiments of this study are 0. 4 and 0. 2 m⁄ s respectively which shows that, all experiments were carried out at the clear water condition. Results: The results showed that by decreasing the relative distance between bridge pier and abutment (􀭋 􀮽 ) from 6. 66 to 3. 33, the maximum scour depth at pier and abutment increased by 8. 1 and 12. 5%, respectively. Also, the rectangular debris caused the most scour depth in comparison with the other debris shapes. By increasing the relative thickness of the semi-cylindrical debris (􀭘 􀳏 􀭈 ) from 1 to 3, the maximum scour depth around the pier and abutment was respectively increased by 7. 64 and 24. 21. In addition, the experimental results showed that the effective length of debris has a significant influence on the dimensions of scour hole, so that, the maximum scour depth in the presence of semi-cylindrical debris with relative effective length (􀭈 􀳏 􀭈 ) of 10, increased by 50. 8 and 58 percent compared with that of the reference test, for the bridge pier and abutment, respectively. Conclusion: According to the results of this study, it was found that the accumulation of debris at the upstream of bridge pier increased the local scour depth around bridge pier and abutment up to 50. 8 and 58%, respectively. There was a direct relation between the scour depth and the debris thickness, so that, by doubling the relative thickness of rectangular debris, the scour depth around bridge pier and abutment was 1. 2 and 1. 05, respectively. With increasing the relative diameter, the scour depth increased at first, thereafter reached to a constant value. For example, for rectangular debris, by changing the relative length from 4 to 10, the scour depth around bridge pier and abutment was increased by 22. 4 and 10. 2%, respectively, but for larger relative lengths, no change was observed in the scour depth. In addition, by reducing the distance between pier and abutment, the maximum depth of scour hole was significantly increased compared with the reference test.

Background and Objectives: Bottom intake is one of the suitable methods for diverting water in mountainous rivers. Among the different forms of bottom intake, that have been studied so far, the use of bottom intake with porous media which can be considered as a suitable substitute for bottom rack intakes due to the reduction difficults of bottom rack and low cost of design and execution. Since the idea of using bottom intake with porous media is new and information is limited to design and construct this kind of intake, the present research tried to consider the condition of the hydraulic behavior of these intakes in accordance with the reality. Materials and Methods: In order to model a bottom intake with porous medium and conduct experiments, a main flume with the walls of the glass materials in the dimensions of the 10* 0. 30* 0. 50 cube meter and a diverted flum by the dimensions of the 1* 0. 45* 0. 50 cube meter was used. To prepar an intake in the distance of 5 m at the beginning of main flume, the space has been considered so that the possibility of conduction is with three length, height and slope (L1=15 cm, L2=30 cm, L3=45 cm) (H1=10 cm, H2=15 cm, H3=20 cm) (S1=0%, S2=10%, S3=20%). The inner surrounding of intake was filled with four different types of gravel with average diameter P1=9. 72 mm, P2=13. 41 mm, P3=15. 30 mm, P4=17. 75 mm. In every experiment by passing different discharges over intake, was measured the rate of diverted discharge for different models of intake was drawn and the effect of different parameters on the rate diverted discharge was studied, by bottom porous intake. We used rectangular weir at the end and beginning of main flume to measure discharge. Results: The results showed that inflow discharge increases the rate of diverted discharge but the proportion of diverted discharge to inflow discharge is on the decrease. By increasing the grain size, the diverted discharge increase, so that grain size P4 has most rate of diverted discharge. It, s the result of void space increasing in this kind of grain size. By increasing uniform coefficient grain of intake, the porosity and void space of granular material decreases, and consequently diverted discharge decreases between 4 and 6 percent. Researching on diverted discharge with different length and height showed increasing intake length from L1 to L3 for intake with height H1 for P2 (d50=13. 41 mm) gradation and Qt=12. 25 lit/s, the Qd/Qt is increased up to 23 percent. Increasing intake height from 10 cm to 30 cm for intake with length 30 cm for P4 (d50=17. 75 mm) gradation and Qt=17 lit/s, the Qd/Qt is increased up to 10 percent. By incearsing the slope of intake surface from 0% to 20%, diverted discharge decrease, this kind of decrease is the result of unexpected change in th surface slope of intake and separating flow in the in enterance of porous media intake. The minimum and maximum the rate of diverted discharge in the experiments in this study was 13% and 90% respectively. Conclusion: The results showed that by increasing the inflow discharge, the diverted discharge increases too; however, for larger values of the discharge, the ratio of the diverted to the upstream flow approaches a final constant value. Grain size of the porous media has a great influence on the diverted flow. By increasing the grain size, the diverted flow increases. By increasing the surface slope of bottom intake with porous media, the diverted flow decreases. Maximum diverted flow occurs at zero surface slope of the intake. Increasing intake length and height, causes increasing in diverted discharge. By using dimensionl analysis, experimental datas and multivariate regression, a new equation to estimated diverted discharge cifficient with coefficient of determination R2=0. 915, was suggested. The theoretical predictions in comparison with the experimental results have shown good consistency.

Background and Objectives: Maintaining water resources as well as economic and fair exploitation of it is a global issue. Today, Due to the lack of water resources in many parts of the world, Disputes over the access to water resources pass national borders and access to these resources has become a strategic objective in interacting between countries. Based on the statistics released by the World Resources Institute in 2015, 33 countries will face the water stress in 2040in which Iran ranked 13. Considering the rainfall average of Iran, the amount of water resources and per capita consumption of the country, Iran can be considered as the countries facing the lack of physical water resources. The objective of this research is to provide the safe water for agricultural use as the most widely used water sector in the country as well as beverage consumption without the use of fresh water sources and only by exploiting the humidity of air. Materials and Methods: In this research, designing a new system to extracting the clean water through the air moisture is considered. The methods applied in this research are the library method, statistical method and analytical method. In this system, a part of the air humidity is separated and appears in the form of droplets of water on the channel wall. Then, The obtained water stored in a tank and use for the considered purpose. Results: In general, the amount of water obtained by this method is varied depending on the climate and other conditions. In this research, the system is studied in Bandar Abbas. So, the water obtained ranged between 5 and 20 liters per hour in warm months. Conclusion: The results show by applying the stated method, especially in warm and humid areas, the acceptable levels of clean water can be achieved. It is necessary to note that all calculations in this paper are based on theoretical relations. So, the clean water obtained through the designed system may not be equal to the numerical value obtained. However, due to the water crisis in the country, achieving half of this amount could also be an acceptable contribution to reducing the water crisis and solving the problem of water scarcity.

Background and Objectives: Nowadays, most of the energy needs of humans are supplied by fossil fuels. Given the decline in fossil fuel reserves and rising emissions and consequent climate change, the production and use of new sources of clean renewable energy with fewer emissions is of high importance. Solar energy is more pronounced among other renewable energy sources, due to the efficiency of energy production. Solar radiation data is used in many industrial applications, photovoltaic systems, agriculture and solar collector design. For this purpose, the fractal dimension is used as a classification criterion. In this study, the estimation of the daily fractal index and the index of purity of sky are used to provide a model that allows classifying the days into three types. In this method, with the advantage of cumulative distribution function, the fractal dimension classifies the days of Karaj station in three classes: clear sky, partially cloudy sky and cloudy sky. Materials and Methods: The database of this experiment includes the total radiation data measured at the Karaj synoptic meteorological station in the period 2014-2016, as well as the sunny hours of the same period from the station. In the first stage after data quality control using moradi algorithm, daily fractal dimension of solar radiation time series was calculated. Daily classification was performed with the help of the fractal dimension data and the Transparency Index of Sky using the cumulative distribution function. According to this method, for each year, two fractal thresholds were obtained using the cumulative distribution function (CDF) and by using these thresholds the days were classified into three classes. Then, monthly data analysis was performed. Results: According to the results obtained at the station, the highest frequency of class 1 was occurred in August 2015, high frequency of class 2 was occurred in February 2016 and high frequency of class 3 was occurred in March 2015. Also, these statistical properties showed that our classification method leads to homogeneous groupings of the studied days since the standard deviations of D and KT were low in comparison with their averages. The more standard deviation of these two variables for class III (upper than 10%) is due to rainy days in this class, which causes the signal Radiation has a regular shape and then the fractal is calculated near to 1. However, the monthly analysis of the fractal dimension allows the detection of the months in which radiation fluctuations are often high or in which the radiation pattern is regular. This information is very useful in determining the size of photovoltaic systems in order to reduce the cost of initial design and the construction of solar energy systems appropriate to the climate of the study area. Conclusion: In this study, a new method has been proposed for classification of radiation per day according to different weather classes, in order to use photovoltaic systems and solar energy in the study area. This method has been proposed to classify the daily global irradiances into typical days using the fractal dimension as a basic criterion since it allows quantifying the irradiance fluctuations. This method defines fractal dimension thresholds using the cumulative distribution function. Then shown that it is possible to realize daily solar irradiances classification using the D thresholds obtained from the CDF method. Classification of the daily solar irradiance is important in design and installation of solar energy systems, especially PV arrays. Trends in the patterns of daily solar irradiance became significant information due to the recent interests in renewable technologies. This interest is essentially due to global warming and other negative effects to our environment. Such analyses presented in this purpose are of great interest as they reduce the initial costs by appropriate design and construction of solar energy systems suitable to the climate of the site of interest.

Background and Objectives: Rainfall-runoff modeling is an essential process and very complicated phenomena that is necessary for proper reservoir system operation and successful water resources planning and management. There are different methods like conceptual and numerical methods for modeling of this process. Theoretically, a system modeling required explicit mathematical relationships between inputs and outputs variables. Developing such explicit model is very difficult because of unknown relationship between variables and substantial uncertainty of variables. So far performance models such as neural networks, multivariate models with auto moving average is studied for modeling the rainfall-runoff. So, in this study CARMA and ANN models studied in rainfall-runoff modeling. Materials and Methods: In this research, the multivariate contemporaneous autoregressive moving average (CARMA) models and artificial neural networks (ANN) were evaluated to rainfall-runoff modeling. We define 3 scenario for ANN model. In order to use CARMA and ANN models total annual precipitation and runoff time series in the period of 1975-2015 as for Nazloochaei the catchment area, in 44° 49' in latitude and 37° 40' longitude in the province of West Azerbaijan was used. At first, we checked the data in terms of randomness, trend and Homogeneity by run test, Mann-Kendall test and Wilcoxon test. And then we separated data in two group. One group including 80 presents of data for training and 20 percent of data for validation was assigned. Performance criteria that used, was root mean square error, Nash-Sutcliffe and correlation coefficient. Results: The results indicated that the multivariate contemporaneous autoregressive moving average model had the efficiency accuracy more than artificial neural networks model, because root mean square error in CARMA model was equal 7. 7 and that was in ANN model 9. 50 m3/s. Also, CARMA model according to the Nash-Sutcliffe criteria and R2 equal to 0. 41 and 0. 54 had better performance than the ANN model. However, the value of these performance criteria in ANN model was equal 0. 45 and 0. 80. So CARMA model has more Accuracy than ANN model in rainfall-runoff modeling. Conclusion: According to the obtained results, using multivariate ARMA models caused to decrease in model error up to 18 percentages. So CARMA model had suitable performance in compare with ANN model, and this subject show the importance of to consider Random component in modeling.