JWSS - Journal of Water and Soil Science

The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and shoulder slope positions, in Miandar and Vidjanan catchments. Soil physical properties such as soil texture and particle size distribution, soil hydraulic conductivity, bulk density, mean weight diameter of aggregates, water holding capacity, and the soil organic carbon content were measured. The results showed that land use change of the forest to agricultural lands resulted in a sharp decline in the soil organic matter (52%) and an increase in silt and sand percentage and soil bulk density. Also, deforestation decreased the mean weight diameter of aggregates (from 0.39 to 0.14 mm in Miandar) and clay percent.  It caused a reduction in the total porosity followed by a decrease of soil water holding capacity, and a decrease in the saturated hydraulic conductivity (from 10.34 to 1.86 cm/h), as well. In general, the results proved that the land use change from forest to agriculture severely decreased soil physical quality and its productivity.

Among the heavy metals, arsenic is known as a carcinogen material and its high concentrations in the ecosystem can be a major concern for public health and environment. The aim of this study was to evaluate the risk map of arsenic contamination and the possibility of its entering into the food chain using the fuzzy method in the central part of the Hamedan-Bahar plain. For this purpose, arsenic concentration in 94 points of groundwater and 49 points of surface soil was analyzed and evaluated in the study area. Soil physico-chemical parameters (clay, organic matter and pH), soil and groundwater contamination probability map, and land use map were selected as the input of this method. In the fuzzy method, two operators (and & or) were used. In order to standardize the parameters, the fuzzy linear function was used. Comparing the classified risk assessment using these operators showed that the results of the operator had the maximum trust. So in areas where concentrations of arsenic in soil and groundwater were high, the physico-chemical parameters such as pH, organic matter and clay content of the soil were low and agriculture products had a high ability to absorb heavy metals and ensure its better to use for the operator.

Depletion and consequently reduction in groundwater storage results in numerous harmful environmental effects such as reduction in yields of wells, land subsidence, lowering of water quality and also reduction in storage of surface water bodies having hydraulic relation with aquifers. In this research, groundwater depletion in the Najafabad subcatchment aquifer located in the GavKhouni basin, Isfahan province was evaluated. These studies indicate groundwater depletion and deterioration of the aquifer water quality during the recent years. Zayandehroud River had been effluent and it has recently converted to influent and dominantly recharges the aquifer. The groundwater depletion in this region has been due to wells overpumping and it does not comply with the uniform rainfall variations in recent years. According to the shaly aquifer bedrock, the groundwater depletion cannot be due to leakage through the bedrock. Moreover, the groundwater quality has been deteriorated in all parts of the aquifer, especially in the regional drawdown cones resulted from recently groundwater overexploitation by deep wells. The river leakage to the aquifer is predicted to be persistent and increasing according to results of the research and it is necessary to limit the groundwater extraction and change the average surface water inflow to the area to mid 1370s condition.

Scour around structures in the river is the most destructivr factor of these structures. Therefore, different methods have been studied to reduce it. A creation slot is one of these methods in the suitable position that can be modified to control the flow pattern scour. In this study, the effects of using two parallel chord rectangular slots  in the single spur dike  with the opening of the effective spur dike area of 10% and a ratio of a/b = 4 (a and b are the length and width of the slot) on two occasions were investigated, one near the bed (near the slot spur dike) and the other near the water surface (away from the nose of spur dike) on the pattern of erosion and sediment around the nose triangular spur dike in clear water conditions. In all experiments, flow depth and angle of the triangular spur dike installation angle were constant. The experiment was done in different hydraulic conditions (Froude number 0.287, 0.304, 0.322). Eventually the results of spur dike without slot (control experiments) were compared. The results showed the slot near the bed toward the slot near water surface and control experiments had a better performance in reducing the maximum depth of scour and deposition of sediments washed to the outer bank. The reduction of the maximum depth of scour at the slot near the bed in Froude numbers 0.287, 0.302 and 0.322, respectively, was  compared to the control experiments , which were 23%, 13% and 24%, respectively, and then compared to the slot near the water surface, which was 60%, 40% and 32% respectively.

Factor analysis is one of the multivariate statistical techniques that considers the interrelationships between apparently irrelevant variables and helps researchers to find the hidden reasons for the occurrence of an event. In order to evaluate the effects of different irrigation levels and humic acid foliar application and identify the factors affecting water use efficiencies of sesame (Sesamum indicum L.), maize (Zea mays L.) and common bean (Phaseolus vulgaris L.), a split plots experiment based on RCBD design with three replications was conducted during the 2014-15 growing season, at the Research Farm of Ferdowsi University of Mashhad, Iran. Irrigation levels (50 and 100% of water requirement) and foliar application and non-application of humic acid were assigned to main and sub plots, respectively. The results showed that in sesame, the highest seed yield and biological yield were obtained from 100% of water requirement and humic acid spraying treatment. In maize, humic acid spraying under condition of supplying 50% of water requirement increased seed weight per plant, plant height, and leaf area index and soil pH In bean, the highest seed weight per plant, plant height, leaf area index, crop growth rate and soil phosphorous content were observed in the treatment of 100% of water requirement and humic acid spraying. Factor analysis results also showed that in sesame, the variables of seed yield, biological yield, seed weight per plant, plant height, leaf area index, crop growth rate, soil phosphorous and water use efficiency were assigned to the first factor and the variables of soil nitrogen, soil pH and EC were assigned to the second one. In maize, seed yield was assigned in the same group with the variables of biological yield, leaf area index, crop growth rate, soil phosphorous, EC and pH and water use efficiency; in bean, this was with the variables of seed yield and water use efficiency. In general, the research results revealed that identifying the effective variables in each factor and those logical nominations according to Eco physiological knowledge can lead to the direct management of effective variables with regard to associated factor, thereby leading to water efficiency improvement.

The irrigation and drainage network of Zarrinehroud with an area of 65,000 hectares is the most important network of Lake Urmia basin, with the direct link to the lake. With the current crisis in the lake, an assessment of the existing network's performance is essential in the Urmia Lake Rescue Program. The purpose of this study was, therefore, to evaluate the transmission, distribution, and utilization efficiency and irrigation efficiency at the surface of the network. Three products were selected from the cultivar with the highest crop area (10% beet, 22% and 22%, and 38% wheat). The dominant method of irrigation was surface irrigation. At the network level, soil moisture in the field before and after irrigation, soil physical and hydraulic properties and water use volume for irrigation were measured. The results showed  that the average transmission efficiency in canals with the concrete coating of the network was about 79%, which was  in the range of 33% (in the  smaller channels) to 100% (in the  larger channels). The water distribution efficiency in the network was, on average, 76%, varying from 50% to 100%. Water use efficiency in the fields based on soil moisture balance analysis varied from 41% in the sandy loam soils to 66% for the clay texture. Based on the analysis of the data on the amount of harvest, production costs and product sales price, the water use efficiency (in kilograms of product per cubic meter of water used) varied from 0.4 for the  elderly hay to 5.1 for the  sugar beet. The amount of water used in this network (in Rials per cubic meter of water consumption) was between 2740 for alfalfa aged over 10 years and 6900 for wheat. It can be concluded that in the case of water constraints, wheat, sugar beet and alfalfa could be the most economic cultivar, respectively.

The aim of this study was to evaluate the effect of increasing DEM spatial resolution on the assessment of the morphometric characteristics of waterways, as well as analysis and modeling of it by using RS and GIS techniques. In this study, which was carried out in the south of Darab city DEM 90 m (as one of the most usable data in waterway modeling), increase spatial resolution of DEM attraction algorithm in neighboring pixels with two models including: touching and quadrant neighboring models to estimate the value of sub-pixels. After manufacturing output images for sub pixels in 2, 3 and 4 scales with different neighborhoods, the best scale with the most appropriate type of neighborhood was determined using ground control points (270 points); then, the values of RMSE were calculated for them. The results showed that with using the Attraction model, the accuracy of the output of images was improved and the spatial resolution of them was increased. Among scales with different neighborhoods, 3 scales and quadrant neighboring model exhibited the most accuracy by the lowest value of RMSE for the DEM 90 meter. Evaluation of waterways morphometric features showed that DEM extracted from attraction algorithm had more ability and accuracy in waterways extraction, Extraction of morphometric complications, and information in the study area.

Preferential flow is of great importance in the environment and the human health. So, rapid water transportation and consequently, pollutants and pesticides leak out and get into the groundwater, making it very difficult to measure and quantify. To quantify and describe the preferential flow, two gravity-driven models were used: 1) kinematic wave model (KW) introduced by Germann in 1985), and 2) kinematic dispersive wave (KDW) model developed by applying a second-order correction to the Germann’s model by Di Pietro et al. in 2003. So, the experimental data was obtained using the laboratory mini-rainfall-simulator over cylindrical soil samples at the laboratory. Their parameters were obtained using Solver add-ins in the Excel software. Then, the results were compared using the root-mean-square error (RMSE). The results showed that the KDW model could better predict the preferential flow (with lower RMSE). Also, the regression results showed 1) there was no significant relation between the preferential flow and the total porosity, and 2) there is a significant relation between the preferential flow and the macrospores.

Zinc is essential micronutrients for plants. This element improves plant growth and yield and plays a role in the metabolism of carbohydrates. Zinc deficiency in soils and Iranian crops is possible due to numerous reasons such as calcareous soils, excessive use of phosphorus fertilizers and unbalanced fertilizer use. The effect of zinc solubilizing bacteria on some wheat properties was considered as a factorial experiment in greenhouse conditions based on a completely randomized design. Treatments consisted of four levels of bacteria comprising B₁ (control), B₂ (Bacillus megaterium), B₃ (Enterobacter cloacae) and B₄ (consortium of both bacterium), and ZnSO₄ fertilizer at three levels including Zn₀ (control), Zn₂₀ (20 Kg/ha) and Zn₄₀ (40 kg/ha). During the experiment, some parameters such as plant height and chlorophyll index were measured. At the end of the cultivation period, soil available zinc, dry weight of root and aerial part, and the zinc concentration of the root, shoot and grain were determined. Grain yield and zinc uptake in the grain were also calculated. The results indicated soil exchangeable zinc content was increased significantly (P<0.05) in all bacterial treatments, as compared to the control treatment. The maximum amount of soil exchangeable zinc, grain yield, zinc concentration and uptake in grain were observed in the treatment containing bacteria consortium with the application of 40 kg/ha of zinc sulfate fertilizer, which was followed by the treatment containing Enterobacter cloacae with the application of 40 kg/ha of the zinc sulfate fertilizer. The maximum amount of all measured properties in the treatment containing Enterobacter cloacae and Bacillus megaterium indicated the possibility of applying those bacteria for zinc enrichment in wheat, crop optimal production, and the sustainable agriculture.

In a pressure flushing method, when the water is discharged from the bottom outlet, after a period of flushing, a flushing cone will be formed at the front of the bottom outlet; the dimension of this cone is affected by several parameters such as outlet discharge flow, water depth of reservoir, and the kind of sediments accumulated in the reservoir. In this study, for the effect of cohesive & non-cohesive sediments, a physical model using specific dimensions was employed in order to develop the sediment evacuation method, and them a Semi-Cylinder structure in front of the lower drain was tested. The experiments were carried out using cohesive & non-cohesive sediments under two conditions: with the semi-cylinder and without it, at 90 experiments. The results indicated that the with discharge was increased, on i average, under both conditions and the volume of the score cone was increased. With decreasing the water depth, the flow mood was changed to free flushing, increasing the length and volume of the score cone. Semi-Cylinder form, on average, increased the volume of sedimentation and the length of sedimentation; this increase could be due to the formation of a pair of rotating Vortexes inside the Semi-Cylinder structure on both sides of the central axis of the valve.

Urban and industrial wastewaters are considered as the most contaminant of surface water. Entrance   of these pollutants to the river reduces the concentration of dissolved oxygen and aquatic life will be threatened. So, one of the main qualitative characteristics of water resources management is the concentration of dissolved oxygen. The base of the   developed model in this investigation is the convection- diffusion equation in soil. Terms of production and decay of dissolved oxygen were added to this equation. The final equation was discretized using the finite difference method with the implicit scheme. With applying the initial and boundary conditions, the equation set was solved by the Thomas algorithm. The calculations were done by programming in the MATLAB software. For the calibration and validation of the model, data obtained from two reaches of Zayanderoud River, including steel melt and Mobarakeh Steel factories, were used. The temporal and spatial variations of the dissolved oxygen were plotted and compared with the real data and the results of the MSP and CSP models. The results showed that the concentration of the dissolved oxygen could be well predicted through solving convection-diffusion equation with introducing two terms for the decay and production of oxygen. The comparison between the results of the model and two other models showed that the model led to better results in comparison to the MSP and CSP models.

Soil water retention curve (SWRC) reflects different states of soil moisture and describes quantitative characteristics of the unsaturated parts of the soil. Direct measurement of SWRC is time-consuming, difficult and costly. Therefore, many indirect attempts have been made to estimate SWRC from other soil properties. Using pedotransfer functions is one of the indirect methods for estimating SWRC. The aim of this research was to assess the effect of using soil particles percentage in comparison with the geometric characteristics of soil particles on the accuracy of the pedotransfer equations of SWRC and the critical point of it. Accordingly, 54 soil samples of Isfahan province from seven texture classes were used. The most suitable functions for estimating SWRC, parameters of van Genuchten and Brooks-Corey equations, and the critical point of SWRC were selected based on statistical indices. The results indicated that the pedotransfer equations fitted the SWRC data well and the outputs from them were in a good agreement with the independent (validation) SWRC data. The results revealed that using soil particles percentage (sand and clay), bulk density and organic matter content in the point estimation of SWRC was better than applying geometric properties of the soil particle diameter. On the other hand, in the estimation of parametric and critical point of SWRC, using the geometric properties of soil particle diameters resulted in more satisfactory results, as compared with using the soil particles percentage. The NRMSE values indicated that the accuracy of the pedotransfer equations in the lower matric head was greater than that of the higher matric head.

Location of soil moisture sampling in irrigation management is of special importance due to the spatial variability of soil hydraulic characteristics and the development of root system. The objective of this study was determination of the suitable location for soil moisture sampling in drip-tape irrigation management, which is representative of the average moisture in the soil profile (θ_avg) as well. For this purpose, soil moisture distribution (θ_ij) at the tassel stage of maize and one irrigation interval (68-73 day after plant) were measured at the end of season. The results showed more than 70% length of the root of plant was located in 30 cm of the soil depth. By accepting ±10% error in relation to the averaged soil moisture, some region of soil profile was determined which was in the acceptable error range and also near the averaged soil moisture (0.9θ_avg<θ_Rec<1.1θ_avg). By overlapping θ_Rec in one irrigation interval, the appropriate location for soil moisture sampling was the horizontal distance from drip-tape line to 20 cm and the depth of 10-20 cm from the soil surface. To determine the appropriate place for soil moisture sampling, the development of root system and the maximum concentrated root length density in the soil profile extracting the maximal soil moisture should be taken in to account, parallel with the averaged soil moisture.

Fruits and citrus wastes are generated in the food industry in large quantities. Their management in Iran, as one of the major hubs of fruits and citrus production, is of great importance. In this study, the biochar samples were prepared from pomegranate, orange and lemon peel waste produced in a juice factory using the pyrolysis process in the range of 400-500 °C; then their efficiency for zinc adsorption from an aqueous solution was investigated. The kinetic and isotherm data of zinc adsorption were fitted by the linear and nonlinear forms of the Langmuir and Frendlich isotherm models and the first-order and second-order pseudo-kinetics models. The results showed that under the experimental conditions applied, the maximum amount of zinc absorption by biochars derived from pomegranate, orange and lemon peel was 2.42, 1.83 and 3.17 mg/g, respectively. The results of adsorption isotherm models also showed that the use of the linear form could lead to a completely different interpretation, as compared to the original form of the model. Based on the linear forms, the Langmuir isotherm was the best; meanwhile, according to the non-linear forms, the Freundlich isotherm was the best model to describe the adsorption data. In addition, the reaction kinetics indicated that both original and linear models had the same results, and the data were better fitted by the pseudo-second order model.

Nowadays, environmental pollutions especially water pollution is increasingly developing. One of the problems of entering the pollutants to rivers is reduction in the concentration of river dissolved oxygen. In order to manage the water resources, amount of dissolved oxygen should be predicted. This study presents a novel equation for simulating the concentration of river dissolved oxygen by adding the oxygen production and consumption in the river factors to equation for transmission-diffusion of minerals in the soil. The resultant equation was separated in finite differential method and by using implicit pattern. Calculations were done by encodings in MATLAB software. In order to calibrate and confirm the dissolved oxygen model, data derived from Zayanderood River around Zob-Ahan factory of Isfahan and Mobarakeh Steel Complex was used. By using some data, coefficients of model were determined. Analyzing the sensitivity of model coefficients showed that aeration constant (K_r) had the most effect on predicting the model. Since depends on hydraulic parameters of river, sensitivity of depth and pace of river was studied and finally depth of river was introduced as the most sensitive variable.

Rivers are one of the most important source of water supply for drinking and farming purposes. Zard River is one of the surface water resources of Khuzestan province. The purpose of this study is to evaluate the quality of the river water and to observe the trend of changes in the water quality of this river in the Mashin station during the period of 1997-2015 by using the Man-Kendal, Spearman, variance analysis statistical methods and the least significant difference (LSD) and cluster analysis. LSD test shows SAR, Na, Cl, pH parameters up to 2010 (before Jare dam construction) were significant at 95% confidence level compared to 2015 (year of control). No changes were made after dam construction. According to Mann-Kendal non-parametric test, pH, Ca and SO₄ have a significant upward trend to the 0.037, 0.393 and 0.376 respectively, the variables Cl, SAR, Na and temperature have a significant decreasing trend to the -0.387, -0.417, -0.386 and -0.1 respectively. Also Spearman test shows that the dam improved the quality of river water regarding to salinity. Variance analysis show that pH, SAR, Na, Cl, Ca and SO₄ have significant difference. Cluster analysis classified the qualitative data before the construction of the dam in three clusters and after the construction of the dam were divided into two clusters where TDS variable was less distant than other variables. As a result, the quality of the irrigation water is changed downward and the TDS is more similar to the other variables compared.

The aim of this study was the effect of raw water quality on the efficiency of domestic reverse osmosis apparatus in Khuzestan province. The results showed that the purified water quality was related to the quality of entrance raw water. With increasing in salt concentrations (EC) or TDS, purification efficiency was decreased. The cation and anions content of refinery water was related to TDS and EC. The Ca/Na and Mg/Na were decreased due to refinery. The ability of these apparatus to reduction of two valence cations were more than mono valence. As same as this trend was observed for anions. Also, the comparison of the EC of raw water and refinery from these apparatuses had different EC from different raw water entrance. This means of these apparatuses had different efficiency with changes of raw water quality. Generally, domestic water purification systems have better performance in Karun river water treatment than in Kheiryrabad and Karkheh rivers.

Use of the curve gradient of the Soil Water Retention Curves (SWRC) in the inflection point (S Index) is one of the main indices for assessing the soil quality for management objectives in agricultural and garden lands. In this study Anneling Simulated – artificial neural network (SA-ANN) hybrid algorithm was used to identify the most effective soil features on estimation of S Index in Jiroft plain. For this purpose, 350 disturbed and undisturbed soils samples were collected from the agricultural and garden lands and then some physical and chemical soil properties including Sand, Silt, Clay percent, Electrical Conductivity at saturation, Bulk Density, total porosity, Organic Mater, and percent of equal Calcium Carbonate were measured. Moreover, the soil moisture amount was determined within the suctions of 0, 10, 30, 50, 100, 300, 500, 1000, 1500 KP using pressure plate. Then, the determinant features influencing the modeling of S Index were derived using SA-ANN hybrid algorithm. The results indicated that modeling precision increased by reducing the input variables. According to the sensitivity analysis, the Bulk Density had the highest sensitivity coefficient (sensitivity coefficient=0.5) and was identified as the determinant feature for modeling the S Index. So, since increasing the number of features does not necessarily increase the accuracy of modeling, reducing input features is due to cost reduction and time-consuming research.

Droughts are natural events and could lead to declining surface water quality of regional basin. Understanding the complex impacts of drought may help authorities to monitor changes in different regional basin and to make appropriate decision on development of a river basin management plan. In this study 20 years annual precipitation time series from 1994-2013 from 7 synoptic weather stations located in the Halil-Rood basin were analysed using both Standard Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) and then dry (-1.35 to -1.75) and wet years (1/7 to 2.45) were determined by model simulation studies. Several climate based drought indices and remotely sensed based drought indices were used for monitoring and evaluating of drought. The impact of drought on the water quality parameters in the study area was evaluated. Results showed that there was significant relationship between most of the examined water quality parameters (Ca²⁺, Mg²⁺, HCO^3-, SO4²⁺, Na⁺, total dissolved solids TDS, SAR) and drought, however there was no significant relationship between water pH and drought. The study indicated that focus on the drought indices might be helpful as a tool in improving surface water resources management under drought condition and may promote sustainable water resources utilization and management in the study area. Also, dividing the Halil-Rood basin into several homogeneous regions is recommended for future studies to prepare a better ground for studying the effect of drought on the quality of water at a regional scale.