JWSS - Journal of Water and Soil Science

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Studies on the soils of western Golestan province show that regardless of increased rain and presence of clay minerals with high cation exchange capacity, potassium extractable with ammonium acetate is low. In order to find the reason for this low amount of available K, clay minerals and micromorphology of the soil porosity were studied. Twenty disturbed and undisturbed samples from each horizon were taken for physicochemical properties, mineralogy and micromorphological studies. Four selected profiles included Gypsic Aquisalids, Typic Endoaquepts, Typic Calcixerolls and Typic Hapludalfs. The results showed that in addition to the clay content and type of clay minerals in soils that can affect soil available K (Kava.), it seems soil porosity can also affect Kava. mainly through their effects on extension of roots, water and nutrients transmission. Favorable content of clay and dominance of smectites in Mollisols and also higher porosity and dominance of channel porosities caused the presence of higher Kava, in these soils. presence of HIS. poor soil drainage, reduction of Fe3+ in smectite crystal lattice in Inceptisols, and also less amount of porosities caused the presence of higher potassium fixation and reduction of Kava. in these soils.

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In order to study land degradation from the soil genesis and micromorphological perspective, ten soil profiles were dug and described on five slope positions in both forest and deforested cultivated land. The soil samples were taken from all horizons for physico-chemical analysis and micromorphological studies. Forest soils had a well developed argillic and calcic horizons and also mollic epipedon. These soils were classified as Alfisols and Mollisols. Carbonate leaching into the depth of soil profile and translocation of clays to lower layers and formation of developed soils are by no means related closely with the dense forest cover and its subsequent landscape stability and favorable leaching conditions. Dominant soil orders in this area were Inceptisols and Mollisols. In cultivated landuse, no argillic horizon was observed except in toeslope position. Absence of argillic horizon or its elimination following deforestation is one of the most important and obvious pedogenetic evidences of land degradation after land use change. Outcropping of high carbonatic layers (calcic horizon), disappearance of mollic and formation of ochric epipedon, presence of redoximorphic features attributed to runoff in lowland, decrease of solum thickness, and change of soil color were the other pedogenic indicators for land degradation in the study area. Microscopic observations showed that granular and crumb microstructures with high porosity were converted to massive and compact ones with low porosity in the deforested area. Disappearance of clay coatings besides absence of excremental pedofeatures were the other important micromorphological evidences of erosion and land degradation.

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Increase in soil bulk density and reduces in porosity and infiltration rate are the most common disturbances during timber harvesting and ground-base skidding. The present study was conducted to study soil physical properties e.g., soil bulk density, moisture, porosity and soil hydrological properties e.g., soil infiltration from ground-base skidding in twenty years since logging. After initial survey, four abandonment skid trails were selected with similar pedologic, climatic conditions and physiographic and different age in Necka-Zalemrod catchment in east of Mazandaran province. Results indicated that impacts of machinery traffices in high traffic intensity have remained yet 20 years since logging. Means soil bulk density, porosity and void ratio were 42.4 greater, 24.6 and 46.7 percent, respectively, lower than the undisturbed areas. The least infiltration rate was recorded in 1-5 years old skid trail, so the reduction of water was not considerable within 18 minutes after experiment into soil in inner ring in this skid trail. Results in each skid trail firmed that in low traffic intensity soil physical and hydrologic properties was tent to “normal” recover in compare to the undisturbed areas.

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Due to soil and plant zinc (Zn) deficiency and its effect on reducing yield and quality of agricultural products, application of Zn fertilizers has been intensified in recent years. To achieve optimum fertilizer management, knowledge of factors affecting Zn availability in soil and its uptake by plant is required. Therefore, this study was carried out to investigate the effect of certain soil physiochemical properties on Zn availability in soil and its uptake by corn. The experiment was laid out in a completely randomized design with factorial combination and three replicates in the research greenhouse of Isfahan University of Technology, in winter 2009. In this greenhouse experiment, 11 soil series were exposed to two Zn levels (0 and 15 mg Zn kg−1 in the form of zinc sulfate). The results indicated that Zn application significantly increased the dry matter weight and shoot and root Zn concentration of corn, although the magnitude of this increase varied depending on the soil type. There was no significant correlation between the DTPA-extractable Zn and the uptake of this nutrient element by corn. There was a negative significant correlation (P < 0.05) between the equivalent calcium carbonate content and available P with the DTPA-extractable Zn. A significant linear relationship (R2 = 0.31) was found between the buffer capacity of soil for Zn and clay content. According to the results obtained from the stepwise regression analysis, the DTPA-extractable Zn and buffer capacity of soil for Zn were not correlated with other measured soil properties.

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The Marls are unstable sedimentary formations that contain chemical materials and destructive particles. Marls Erosion processes are very intensive, so different forms of erosion on the marls as badlands are of specific characteristics in marl lands. Hence, recognition of effective characteristics in marls erodibility is necessary to adopt corrective measures and methods. In this research, for assessing marls erodibility in Hablehroud watershed portable rain simulator was used. Runoff and sediment amounts were measured in each marl unit. Then effective Factors were identified using statistical parameters. Finally, by factor analysis we determined the relationship between marls chemical properties and sediment yield. Therefore, effective parameters of erosion and sediment yield were determined. Results showed sediment yield is decreased in gypsum marl, sandy marl, salt marl and limy marl. In addition, erosion and sediment yield are increased with increasing EC, Na, Cl, SAR and with decreasing TNV, HCO3

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In this study the effects of irrigation with raw or diluted municipal effluents along with foliar micro-nutrients fertilizer spray were examined on the growth, yield and mineral nutrient in foxtail millet plants. The experimental design was a split-plot with three irrigation sources (namely raw sewage, 50% diluted sewage and well water) as main-treatment and four combinations of Mn and Zn foliar spraying as sub-treatments, which were applied with three replications. The experiment was conducted at the Zabol University research farm during 2009. The applied municipal effluents contained higher levels of macro and micro-nutrients than the well water. The experimental results indicated that irrigation of plants by raw or diluted sewage improved the measured growth parameters and productivity of foxtail millet plants. In addition macro and micro-nutrients concentrations were improved. These improvements were attributed to the presence of high levels of essential nutrients such as nitrogen, phosphorus, and organic matters in wastewater. Manganese and Zn supplied through sewage water alone were not able to raise the productivity of millet to the level obtained through fertilizers at the recommended level, which indicated that additional nutrients through fertilizers are required to obtain higher productivity of millet under sewage farming. Despite the differences in nutrients concentration among different irrigation water sources, the micro-nutrients foliar spray did not affect concentration of macro and micro-nutrients in foxtail millet plant. Overall, the results suggest that municipal sewage could be efficiently utilized as an important source of water and nutrients in growing foxtail millet Sewage water irrigation did not have any appreciable harmful effect on crop productivity.

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Models are helpful tools to predict runoff, sediment and soil erosion in watershed conservation practices. The objectives of this research were to investigate sensitivity analysis, calibration and validation of EUROSEM model in estimation of runoff in Tangh-e-Ravagh sub-basin of Karoun watershed. The model was tested in a one hectare experimental test site. The area was divided into nine elements according to EUROSEM user's manual. A triangular weir was installed at the outlet of the area to collect runoff in specified time periods for six rainfall events. Sensitivity analysis of the model was performed by a ±10% change in the dynamic parameters of the model and examining the outputs for a rainstorm. Sensitivity analysis showed that total runoff was sensitive to saturated hydraulic conductivity and insensitive to soil cohesion. Sensitivity analysis indicated that the model sensitivity depends on evaluation conditions and it is site-specific in nature. Calibration and validation of the model was performed on input parameters. Calibration of hydrographs was performed by decreasing saturated hydraulic conductivity and capillary drive and increasing initial soil moisture. Validation results showed that EUROSEM model simulated well the total runoff and peak of runoff discharge, but it could not simulate well the time of runoff, time to peak discharge

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In this research, we estimated soil shallow depths temperatures using regression methods (Linear and Polynomial). The soil temperatures at soil depths (5, 10, 20, 30, 50 and 100 cm) were correlated with meteorological parameters. For this purpose, temperature data of Hamedan station (in the period 1992-2005) were employed. Soil temperature data were measured on a daily basis at 3 PM, 9 PM and 3 AM. MS Excel was used for deriving the regressions between soil temperature and meteorological parameters (air temperature, relative humidity and sunshine hours). The results showed that the highest coefficient of determination (R2) of the linear regression was between soil temperature in 20 cm soil depth and air temperature at 3 AM (R2= 98.15%) and the lowest value in 100 cm soil depth at 3PM (R2= 83.96%). Also, the highest R2 of non-linear regression was observed between soil temperature in 10 cm soil depth and air temperature at 3 AM (R2= 98.45%) and lowest value in 100 cm soil depth at 3PM (R2= 84.11%). The results showed that the highest and lowest values of R2 of linear relations between meteorological parameters (relative humidity and sunshine hours) and soil temperature were observed in 10 cm soil depth (at 3 AM) and in 100 cm soil depth, respectively. Correlations of soil temperature with air temperature were greater than those with the other two parameters. Moreover, R2 values of non- linear relation were higher than linear relation.

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The present paper tries to describe the advantage and improvement of a numerical model when predicting government processes on Flow Rivers. With regard to the important effect of the flow velocity and shear stress forces on river bank erosion, we apply a Two-Dimensional numerical model, named CCHE2D, to simulate river flow pattern at a meandering river Khoshk-e-Rud River of Farsan, 30 Km west of Shahr-e- Kord. Various algorithms and parameters were implemented in a computational fluid dynamic model (CFD) for simulation of two-dimensional (2D) water flow to gain an insight into the capabilities of the numerical model. At this surveying, at first, we applied the topographic maps of the studied location and then, made the model geometry and calculation mesh with diverse dimensions. Finally, using the measured properties of the river flow and the Depth-Average, Two-Dimensional Hydrodynamic Model was run. Then, we obtained the results of model, such as depth and flow velocity at the river meander. Within the scope of the test cases, the model simulated water flow pattern processes at an intake, as well as a steady flow regime in a sine-shaped meandering channel by a 90_channel bend, which is the free-forming meander evolution of an initially straight channel. Because of high accuracy of this numerical model and multiple content of its internal parameters, the evaluation result of model, confirmed the measurement results. Therefore, the parameters gained from the model showed good conformity with measurement parameters at field cross-section. All results matched well with the measurements. The results also showed that using computational fluid dynamics for modeling water flow is one step closer to having a universal predictor for processes in Meandering Rivers

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The aim of present research is landslide hazard zoning using Bayesian theory in a part of Golestan province. For this purpose, landslides inventory map was created by landslide locations of landslide database (392 landslide locations). Then, the maps of effective parameters in landslide such as slope degree, aspect, altitude, slope curvature, geology, land use, distance of drainage, distance of road, distance of fault, stream power index (SPI), sediment transport index (STI), and rainfall were prepared in GIS environment. Relationship between effective factors and landslide locations were considered using Bayesian probability theory. In the next step, parameters classes weights were found and the landslide susceptibility mapping was achieved by fourteen modeling approaches (using whole parameters and deleting parameters one by one). The verification results by ROC curve and 30% landslide locations showed that the Bayesian probability model has 71.37% accuracy for the second approach of modeling in the study area.

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Climate situation changes over a year cause changes in some soil characteristics and soil sensitivity to erosion. Investigation of these changes and how they impact on erosion can be of particular importance. This study investigated changes in Sediment Productivity and soil factors affecting these changes in Tiregan rangeland located in Daregaz city in Khorasan Razavi province. In this study, using the position of the upper and lower hillside of eastern and western aspects, the sampling with rain simulator was performed. Characteristic features of sediment yield including runoff threshold, runoff volume, sediment and turbidity were measured. Soil samples were taken from each sample rain simulation and features of the initial moisture content, bulk density, electrical conductivity, pH and organic matter were measured. Sample was collected with the same intensity and duration of the instrument with fixed locations, and was repeated in four seasons. In order to obtain the position and orientation of each of the parameters in the data obtained at different seasons, the combined analysis of variance test was used. The effect of each of these parameters and the difference between them were evaluated using the Tukey test, and the graphs in 2007 Excel software were plotted. The results showed that all the parameters of sediment yield during the year have significantly changed. The maximum amount of sediment production rates occurred in autumn and was gradually reduced. Its decreasing in both winter and spring can be attributed to vegetation in the area.

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In order to investigate the effects of municipal solid waste enriched with mineral fertilizers on some soil physical properties and lead (Pb) and chromium (Cr) concentration in plant organs of spinach, a field experiment was carried out in a factorial arrangement based on the randomized complete block design with three replications in 2008. The main plot included four levels of fertilizer, control without fertilizer, 20 tons of multiple solid waste + 50% chemical fertilizers and 40 tons of multiple solid waste + 50% chemical fertilizers per hectare and sub-plot consisted of a period of application in 3 levels of time (one, two and three years). The results showed that application of enriched municipal compost increased field capacity, soil porosity and moisture holding capacity, but particle and bulk density of soil decreased compared to the control. Also, the physical parameters in the two levels of emriched waste compost were higher than chemical fertilizer treatment. On the other hand, using for three-years the urban waste compost enriched fertilizer at all levels increased significantly (p 0.05) lead and chromium concentrations in spinach. The Pb and Cr accumulated in roots and shoots of spinach in urban using 40 tons of waste compost per hectare with 50 percent of chemical fertilizer for a period of three years and showed a significant increase. The amounts of fertilizer in all three levels were higher than the root element shoot.

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Stage – discharge relationship is mainly developed from measured data in any hydrometry station. Measured data usually obtain in low to medium flow discharge, because in most cases it is very difficult to measure the flow discharge during flood. Therefore, the stage–discharge is extrapolated beyond the measured data to compute the flood which may estimate low or higher value. This is because during the high flow, the bed form is developed which causes the flow resistance to change. In order to establish a better stage – discharge relation, it is important to apply methods which consider the bed form resistance. In this study an attempt has been made to determine the best method for developing such relationship. To reach the goal, the required data such as river cross section, discharge and related stage and bed material gradation from Ghorbaghestan hydrometry station were measured for two years. Then a computer program was developed. Using this program and applying the measured data, the stage – discharge relationships were computed by five different methods. From the statistical comparison of the results of these methods with measured data, it was found that Shen, Brownlie, Engelund and White’s method overestimate the flow discharge. The best method was found to be the Einstein – Barbarossa’s method that provided the minimum absolute mean errors 0.31 and 1.468 m3/s and minimum root mean square error 0.112 and 0.466 m3/s for the two study years, respectively

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Nitrate leaching from agricultural lands can pollute groundwater, and the degree of pollution caused significantly depends on agricultural practices implemented on farms. Field studies required to evaluate the effects of various agricultural management strategies on nitrate leaching are expensive and time consuming. As a result, it is suggested to use crop models to simulate the effects of management practices on nitrate leaching. Plant growth models such as DSSAT software package can simulate daily plant growth and development, and also are capable of simulating daily nitrate leaching and nitrogen uptake by plants. However, it is required to evaluate the performance of any model before using it for any specific region. In this study, the performance of nitrogen balance model of DSSAT software package was evaluated to simulate nitrate leaching from the root zone of silage maize at different levels of applied water and nitrogen fertilizer. The experiment consisted of three levels of nitrogen fertilizers, including zero, 150 and 200 kg N ha-1 and four levels of applied water 0.7SMD (soil moisture depletion), 0.85SMD, 1.0SMD and 1.13SMD. Nitrate-nitrogen leaching from 36 plots at the 60 cm depth during the growing period was measured by soil moisture suction equipment (ceramic suction cups, CSC). After calibrating the model by using field data, its performance was evaluated to simulate nitrate leaching. Maximum amount of N leaching 8.4 kg N ha-1 was obtained from over irrigation treatment with the application of 150 kg nitrogen per hectare. The model simulated nitrate leaching for this treatment as 7.8 kg N ha-1. The model consistently underestimated the nitrate leaching however, it followed the behavior of nitrate leaching during the growing season. In deficit irrigation treatments, the nitrate leaching was very low and close to zero and the model simulated the same result accordingly. The results showed that the model, in addition to phenological stages and performance indicators, can simulate nitrate leaching from the root zone and could be used to evaluate the effects of various irrigation and fertilizer management strategies on nitrate leaching.

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In order to evaluate the effect of arbuscular mycorrhizal (AM) fungi and Pseudomonas fluorescens bacteria on phosphorus fertilizer use efficiency, mycorrhizal dependence and grain yield and dry matter yield of maize under water deficit conditions, a field experiment was conducted as split-split plot arrangement based on randomized complete block design with three replications. The treatments in this experiment were included as follows: irrigation (normal irrigation and water deficit stress based on evaporation from class A pan evaporation) combined different seed inoculations with AM and Pseudomonas fluorescens and treatment of chemical phosphate fertilizer (non- consumption of phosphate fertilizer, consumption of 50 percent of triple superphosphate fertilizer needed, and consumption of rock phosphate, based on the quantity of consumed phosphorus of triple superphosphate source). The results showed that effects of irrigation, seed inoculation with AM and Pseudomonas fluorescens biological phosphate fertilizer and chemical phosphate fertilizer were significant on yield and yield components, dry matter yield, relative agronomic efficiency and root colonization. Mild stress significantly reduced grain yield, relative agronomic efficiency and fertilizer agronomic efficiency compared to optimum irrigation. Results showed that grain and dry matter yield are highly correlated with root colonization under mild stress condition. Maximum mycorrhizal dependence was obtained in mild stress condition. Maximum relative agronomic efficiency, fertilizer agronomic efficiency, yield and yield components was related to seed inoculation with AM and Pseudomonas fluorescens. The use of triple superphosphate fertilizer were increased grain yield in comparison with rock phosphate along with inoculation of phosphate solubilizing microorganisms. However, maximum root colonization and mycorrhizal dependence was achieved in non- consumption treatment of phosphate fertilizer.

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Organic carbon is the most important component of terrestrial ecosystems and any change in its abundance can have a major impact on the processes that take place in ecosystem. The aim of this study was to estimate carbon sequestration in three different elevations (200 to 1200 m from sea level) and according to vegetation type in the Khairoodkenar forest. The highest carbon sequestration was observed in the surface layer of a soil with Fig-Carpinus betulus vegetative cover and it was estimated to be 167.4 ton/ha. But when carbon sequestration was measured in soil solum, it was found that soils with Fagus orientalis-Carpinus betulus vegetation cover had the highest amount of organic carbon (514.4 ton/ ha). The results showed that clay fraction had the highest carbon content but the highest enrichment factor (1.59) was measured for sand fraction in soils with Fagus orientalis- Carpinus betulus vegetative cover. The highest organic carbon content (7.89%) and aggregate stability (MWD= 7.79mm) and lowest bulk density (1.21 g/cm3) were measured in soils with Figs- Carpinus betulus vegetative cover.

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Free and uncontrolled pasture grazing by animals may decrease soil aggregate stability through reductions in plant cover and subsequent soil organic C, and trampling. This could expose the soil surface layer to degradation and erosion. The objective of this study was to determine the influence of pasture management (free grazing, controlled grazing and long-term non-grazing regimes) on aggregate-size distribution and aggregation parameters by wet and dry sieving methods in two native pastures, protected areas in Chaharmahal va Bakhtiari province. The studied pastures were 1) SabzKouh pastures protected from grazing for 20 years, and 2) Boroujen pastures protected from grazing for 25 years. Soil samples were collected from 0-15 cm depth during the grazing season in summer 2008. Samples (finer than 2 mm) were analyzed for aggregate-size distribution and aggregation parameters by wet and dry sieving methods. Results showed that pasture management had a significant influence on aggregate-size distribution and aggregation parameters in the two areas. The two methods indicated that macro-aggregates in non-grazing and controlled grazing regimes were higher than those in free grazing regime, whereas in free grazing management micro-aggregates showed an opposite trend, and were greater compared with the other grazing regimes. Similarly, soil aggregate stability indices (i.e. mean weight diameter, aggregate geometric and ratio mean diameter) were all improved by non-grazing regimes, suggesting that animal grazing and trampling break down large soil aggregates due largely to compaction and reduced plant coverage. However, the extent to which grazing affects soil aggregation depends in large part on grazing intensity and duration, and the area involved.

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Physicochemical characteristics of soil, land cover/use and human activities have effects on heavy metals distribution. In this study, we applied Classification and Regression Tree model (CART) to predict the spatial distribution of zinc in surface soil of Hamadan province under Geographic Information System environment. Two approaches were used to build the model. In the first approach, 10% of total data were randomly selected as test data and residual data were used for building model. In the second approach, all data were used to build and evaluate the CART model. Determination coefficient (R2) and Mean Square Error (MSE) were applied to estimate the accuracy of model. Final model included 51 nodes and 26 terminal nodes (leaf). Calcium carbonate, slope, sand, silt and land use/cover were determined by the CART model to predict spatial distribution of Zn as the most important independent variables. The regions of western Hamadan province had the highest concentration of Zn whereas the lowest concentration of Zn occurred in the regions of northern Hamadan province. The results indicate good accuracy of CART model using R2 and MSE indices.

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Iron chlorosis is an important disorder of plane trees (Plantanus orintalis L.) in green space of Isfahan city. Before using reclamation methods for correcting Fe chlorosis, it is necessary to find a suitable index for evaluating plant Fe status. Therefore, activity of glutathione peroxidase (GP) enzyme and concentration of carotenoids and chlorophyll a and b pigments, as physiological indices of active Fe, were compared to total Fe concentration in leaves to evaluate Fe status in plane trees. For this purpose, severity of chlorosis of plane trees at different regions of Isfahan city was recorded. Then, 73 trees with different severity of chlorosis symptoms were selected and their leaves were sampled on July 2009 and 2010. Concentration of Fe, chlorophyll a and b and carotenoids in leaves as well as activity of GP enzyme were measured. Results showed large variation in leaf Fe concentration between young and old leaves and also between leaves with different chlorosis severity symptoms. No correlation was found between leaf Fe chlorophyll concentration and severity of chlorosis symptoms. Also, concentrations of chlorophyll a in young and old leaves with very severe chlorosis symptoms were 44 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of chlorophyll b in young and old leaves with very severe chlorosis symptoms were 40 and 37% smaller than that in young and old leaves with slight chlorosis symptoms, respectively. Concentration of carotenoids varied among young and old leaves with different severity of chlorosis symptoms. Activity of GP in young leaves was also reduced by intensifying severity of chlorosis symptoms. According to the result of the present study, activity of GP enzyme and leaf concentration of carotenoids and chlorophyll a, as suitable physiological indices of active Fe, had close correlation with severity of Fe chlorosis in plane trees. Also, deficiency of active Fe in leaves is a probable reason of chlorosis symptoms in plane trees.

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Zinc (Zn) is an essential trace element for plants as well as for animals and humans. There is a significant relationship between soils, plants and humans Zn status in a certain agro-ecosystem. The objectives of this study were to assess Zn status of soils in 3 arid and semiarid provinces of Iran and to model the relationship between wheat grain Zn and agro-ecosystem parameters. About 137 soil and wheat samples were collected randomly from the agricultural soils of Fars, Isfahan and Qom and were analysed in laboratory. Modeling the relationship between wheat grain Zn and agro-ecosystem parameters was done using least square based and robust methods. The results indicated that total Zn concentration of soils (range, 21-149 mg kg-1 mean, 75.2 mg kg-1) was in normal ranges. The DTPA-extractable Zn concentrations were below the critical level (0.8 mg kg-1) in 16% of the surveyed fields. The Zn concentration in 80% of wheat grains was sufficient (more than 24 mg kg-1) with respect to plant nutrition (range, 11.7-64 mg kg-1 mean, 31.6 mg kg-1). However, Zn bioavailability for consumers was generally low in more than 75% of the samples. This is because of high phytic acid to Zn molar ratio (more than 15). Soil DTPA-extractable Zn and available P were entered in to most of regression models significantly. Regression analysis showed that most of models fitted to wheat grain Zn concentration and soil Zn and influenced by agro-ecosystem parameters had a weak prediction power, despite their high determination coefficient. This means that factors other than those considered here have a strong influence on the uptake of Zn by wheat in these soils.