JWSS - Journal of Water and Soil Science

In order to assess the status of the iron (Fe) chlorosis of plane trees in green space of Isfahan city, the chlorosis intensity of 73 trees in different regions was recorded as (1): low (less than 5% of leaves), (2): moderate (less than 50% of leaves), (3): severe (more than 50% of leaves), and (4): very severe (more than 95% of leaves). The whole leaf (with petiole) samples were taken from the top and bottom of each tree, separately, during 2008 and 2009. Then selected chemical properties of the leaves were analyzed.  The results showed that in more than 95 and 71% of the young leaves, Fe concentration was less than the critical deficiency level (202 mg/kg). Concentration of Fe in the older leaves of all plane trees even those with slight symptoms of chlorosis was less than the critical level (382 mg/kg). No significant relationship was found between the leaf zinc concentrations and intensity of iron chlorosis. In more than 92 (in the first year) and 87% (in the second year) of the plane trees, Zn concentration of young leaves and in all trees, Zn concentration of old leaves were less than the critical deficiency concentration (23 mg/Kg). The comparison between concentrations of Cu in the leaves with its critical deficiency level showed that more than 90% of young and old leaves accumulated toxic levels of Cu in both sampling years. In regard with the sufficient range of P, about 79% of the trees in the first year and 53% in the second year accumulated excess levels of this nutrient in their young leaves. This condition was slightly modified for the older leaves so that excessive concentration of phosphorus in mature leaves was not observed in the first year and in the second year, only about 29% of the samples had concentrations higher than critical levels. 

To procure the status of groundwater level fluctuations in arid and semi-arid areas, it is necessary to obtain accurate forecast of fluctuations data. Time series as a linear model have been utilized to generate synthetic data and predict future groundwater level. Minitab17 software and monthly depth of groundwater level data of 20 years (1991-2011) for 25 piezometric wells of plain were used. Time series models of each well were selected and 5 years temporal forecasting was accomplished. The predicted depth of groundwater level data was converted to Groundwater level data using ARCGIS10 and GS+5.1.1 software. Ordinary kriging with a spherical variogram was selected for interpolation of groundwater level. Five years spatial forecasting was done and spatial forecasting and groundwater level drop forecasting maps were prepared. Forecasting results of groundwater level show that over the next 5 years, the area covered by two intervals of groundwater level, 1100-1140 m and 1140-1180 m, will increase and the area covered by three ranges of 1180 -1220 m, 1220-1260 m, and 1260-1300 m, will decline. Also, according to the 5-year groundwater level drop forecasting map of the plain, the highest level of groundwater level drop, more than 16 meters for Qasemabad bozorg areas, located in North East and central of the plain, and the lowest level of the groundwater level drop, about 0.5 m for Mohammad Abad Afkham Aldoleh Lands, located in outlet area of the plain, have been predicted.

In the ICSSDOM simulation-optimization model, simulated annealing algorithm is combined with a hydrodynamic simulation model named ICSS. In this model the ability of weighting of indicators is also considered. In this study, using this model the performance of the S-L-R5 canal in the DEZ irrigation network was evaluated in a period of 10 days. With presenting a proposed method for weighting the indicators and its various options, using parametric sensitivity analysis, optimal adjustment of intake and check structures was obtained. It was found if the coefficient of each index is selected as a direct ratio of the ideal improvement potential of the indicator, the percentage of the improvement is more than the other investigated options. In addition, due to the interaction of the indicators in the multi-objective functions, the consistency of the weighting method with the nature of the optimization problem in this study has been shown. Statistically, the adequacy of the 10-day period of study was confirmed. The model validation with mathematical asymptote method shows 6% error which indicates the model is valid. For example, on the first day, based on the option three (The optimal option), the optimal gate opening for 5 intakes and one check control was between 3.9 to 14.7 Cm. In this condition optimal delivery was between 46 to 178 liters per second.

In this research, a comprehensive simulation model for water cycle and the nitrogen dynamics modeling including all the important processes involved in nitrogen transformations such as fertilizer dissolution, nitrification, denitrification, ammonium volatilization, mineralization, immobilization as well as all the important nitrogen transportation processes including nitrogen uptake by the plant, soil particles adsorption, upward flux, surface runoff losses and drain losses, was used for fertilizer management modeling in a sugarcane farmland in Imam Khomeini Agro-Industrial Company using a system dynamics approach. For evaluating the model the data collected from Imam Agro-Industrial Company equipped with a tile drainage system with shallow ground water and located in Khuzestan province, Iran, were used. The statistical analysis of the observed and simulated data showed that the RMSE for determining the accuracy of simulation of the nitrate and ammonium concentration in drainage water is 1.73 mg/L and 0.48 mg/L, respectively. The results indicated that there is good agreement between the observed and the simulated data. Nine scenarios of fertilization at different levels of urea fertilizer were modeled including one scenario of 400 kg/ha, two spilit scenarios of 350 kg/ha, two spilit scenarios of 325 kg/ha, two spilit scenarios of 300 kg/ha, one scenario of 280 kg/ha and one scenario of 210 kg/ha. Results of the modeling showed that the scenario of 210 kg/ha has the highest nitrogen use efficiency (52.3%) and the lowest nitrogen losses consisted of denitrification, ammonium volatilization and drainage losses (17.82, 7.16 and 92.59 kg/ha, respectively). The results revealed that increasing the consumption of urea fertilizer greater than 210 kg/ha increased the overall nitrogen losses and reduced the nitrogen use efficiency. Meanwhile, this model can be used for managing the fertilizer and controlling the nitrate and ammonium concentrations in the drainage water to prevent the environmental pollution. Also, the system dynamics approach was found as an effective technique for simulating the complex water-soil-plant-drainage system.

Morphologic study of rivers is very important in stabilization and determination of river boundaries. Dams are structures which have the highest effects on river morphology. Studies of river changes are usually time-consuming and possible only in the long-term timescales. To detect these changes, using satellite images over specific time periods and cartographic methods are useful. In the present study, morphological changes of Zayandehrud River, at downstream of Zayandehrud dam, between hydrometric stations of Sad-e-Tanzimi and Pol-e-Zamankhan, were investigated through 7 series of Landsat satellite photos from 1980 to 2015 by applying ENVI 4.8 and Arc GIS10.2 software. Based on the results, the method of enhancing the contrast as saturated linear expansion, along with the edge enhancement filter, was found an appropriate method for determining the boundary between land and water. In the next step, the river path was entered into Arc GIS 10.2, and geometric parameters of the river such as wavelength, sinuosity ratio, central angle and radius of circle tangent to the curve were determined. Also, statistical analysis of geometric parameters was performed by applying SPSS software. Results showed that from 1986 up to now the sinuosity ratio has risen from 2.14 to 2.38, while the radius of river curvatures and wavelength of meanders have decreased by 5% and 11.4%, respectively. Overall, the river has decreased its arcs’ curvature and bends have been moved to downstream. The main cause of this phenomenon is constructions in the river borders (e.g. in Markadeh and Cham-Kaka), which have disturbed the natural situation of the river. In Cham-Jangal, Cham-Khalifeh and Cham-Ali regions, due to the increase in slope and improper vegetation cover, bank erosion has reached to its highest degree. In general, although flood events have been contained by Zayandehrud dam, yet the river has great potential for erosion in the meandering sections.

Improvement of soils is among the major concerns in civil engineering, therefore a variety of approaches have been employed for different soil types. The annual budget of implementing the projects of this kind in countries clearly implies the importance of the subject. The loose granular soils and sediments have always imposed challenges due to their low strength and bearing capacity. Bio-mediated soil improvement has recently been introduced as a novel link of biotechnology (biotech) and civil engineering for improving the problematic soils, i.e. utilizing some bacteria to precipitate calcite on the soil particles. Bio-grouting is a branch of Bio-mediated soil improvement which is a method based on microbial calcium carbonate precipitation. In this regard, the soil samples were stabilized by injecting the bacterium Sporosarcina pasteurii in the first phase of the process and Urea and Calcium Chloride in the second phase of the process (two-phase injection) as the nutrients into the sandy soil columns and subjected to unconfined compressive strength test. In this research, Taguchi method was utilized for design of experience (DOE). Based on results obtained, the activity of the bacteria caused the precipitation of calcium carbonate in soil samples so that after 21 days, the unconfined compressive strength of the soil increased from 85 kPa in the control sample to 930 kPa at optimum condition.

Prioritization of sub-watersheds is very important and necessary in order to implement soil and water conservation practices. This study has prioritized 13 sub-watersheds based on morphometric and land use characteristics using RS and GIS techniques in Haraz watershed to identify erosion-prone sub-watersheds. Morphometric characteristics including bifurcation ratio, drainage density, stream frequency, drainage texture, form factor, basin circularity, compactness coefficient, elongation ratio, length of overland flow, shape index, and basin relief were considered in morphometric analysis. Land use map was classified into seven classes of forest, water-body, irrigated farming, bare land, rangeland, orchard and residential area. Finally, sub-watersheds were classified into four categories as very high, high, medium and low in terms of priority for soil conservation. On the basis of morphometric analysis sub-watershed WS-4 was considered as high priority, whereas according to land use analysis, sub-watersheds WS-6, WS-8, WS-12 were in class of high priority. Sub-watershed WS-4 was categorized as a very high priority class based on the integration of morphometric and land use analysis. This region was identified as critical region therefore should be considered as priority class for implementation of soil and water conservation practices.

This study was done to evaluate the effect of afforestation in sand dunes at the vicinity of Shush, because of the importance of soil protection and wind erosion in sand dunes, also sand dunes afforestation as an effective and long lasting fixation mechanism. The study site was covered by petroleum mulch about 20 years ago and afforested by Prosopis juliflora. To study the effects of afforestation on sand dunes, two 10 ha afforested sites (25-50 and 75-100 percent canopy coverage) and control were selected. In each of studied site 15 plots were established and soil physiochemical properties were determined. Our result indicated that afforestation caused soil texture to change from sandy to sandy-loam. Also, soil phosphorus, potassium, organic carbon and nitrogen increased in 0-5 cm soil depth by afforestation that could be because of nutrient absorption from soil depth and returning to the surface by litter fall compared to the control. This study revealed that 25-50 percent canopy coverage resulted in better soil physiochemical properties compared to control site. In conclusion, sand dunes afforestation not only resulted in sand dunes fixation but also soil fertility and long lasting fixation.

Urea is one of the most commonly used nitrogen fertilizers in agricultural lands. The fate of this fertilizer in soils is greatly related to the soil urease enzyme activity, while this enzyme commonly exists in the adsorbed state on the surface of soil colloids, and especially clay minerals. In order to examine the kinetic properties of free and adsorbed Urease on the surface of sepiolite and vermiculite, an experiment was carried out with eight levels of urea concentration (5, 10, 20, 40, 60, 80, 100 and 120 mM). This experiment was done with enzyme concentration of 1 unit in temperature of 25˚C and pH=7. Adsorption of urease on the clay surfaces affected its kinetic properties compared to the free state. The results showed that urease enzyme obeyed Michaelis-Menten kinetic in both free and adsorbed states on the clay surfaces. Except free urease, the highest and lowest values of V_max and K_m were observed in urease-sepiolite and urease-vermiculite complexes, respectively. Also, the results showed that except free urease, the highest levels of Catalytic Efficiency were related to urease in the presence of vermiculite and sepiolite, respectively. The Effectiveness Factor was more for adsorbed urease on the sepiolite surface than adsorbed urease on the vermiculite surface, and the fact somehow suggests more complete diffusion in the presence of sepiolite.

Traditionally, most corn field in Hamedan Province is prepared for planting by moldboard plowing followed by a number of secondary tillage operations. In recent years conservation tillage systems have become more popular. This research was conducted in the form of a split plot experimental design with six tillage treatments and three replications. Main tillage methods including: (T1) conventional tillage (moldboard plow + cyclotiller equipped with roller), (T2) combination tiller (chisel plow equipped with roller) (T3) bandary tillage with chisel blades were considered as main plots and two P fertilizer application including: (F1) fertilize broadcasting and (F2) fertilizer bandary placement were considered as sub plots. During growing seasons, soil mechanical resistance (cone index), soil bulk density and water infiltration in soil were measured. At the end of the growing season (harvesting time), corn yield and its components were measured. Results indicated that tillage methods and soil depth had a significant effect on the soil bulk density and cone index. The effect of tillage on water infiltration in soil was significant. The effect of P fertilizer application on corn yield was significant (P≤0/01) and P fertilizer bandary placement with mean corn yield of 10862 kg/ha had higher yield value than the fertilizer broadcasting with mean corn yield of 9965 kg/ha. Although the difference between tillage methods for corn yield was not statistically different, T2 treatment with mean corn yield of 10913 kg/ha had higher yield value than the other two tillage treatments (T1 with mean corn yield of 10106 kg/ha and T3 with mean corn yield of 10222 kg/ha).

This study aimed to investigate the dynamic changes of rill erosion and evaluate the ability of Hairsine-Rose model in estimation of sediment concentration. The experiments were carried out at the Soil and Water Conservation Research Station of Tehran University in Kuhin, Qazvin. Four flow rates were tested at three slopes in trapezoidal hand-made rills of 3 m long and 5 cm base width. Outflows were sampled periodically to determine changes in sediment concentration. The experiments were repeated in early autumn and mid spring. Sediment concentration showed a dynamic change with time which was affected by flow rate, slope and season. The sediment concentration was high in the first few minutes of the experiment but over time, dropped and finally reached a more or less stable state. The effects of flow rate and slope were more detectable on sediment concentration at the early unsteady conditions than at the final steady conditions. Though the temporal trends were similar, the sediment concentration was generally higher in autumn than in spring. Hairsine-rose model showed a better performance at lower flow stream powers but generally over predicted sediment concentration showing a systematic error probably due to model formulation.

Accelerated soil erosion in Iran causes on-site and off-site effects and identifying of sediment sources and determination of their contribution in sediment yield is necessary for effective sediment control strategies in river basin. In spite of increasing sediment fingerprinting studies uncertainty associated with magnetic susceptibility properties has not been fully incorporated in models yet. The objective of this study is determination of the relative contribution of sediment sources using magnetic susceptibility properties (High frequency, Low frequency and Frequency dependence) incorporated in uncertainty mixing model. For this purpose, 25 bed sediment samples were collected from the outlet of drainage basin and outlet of sub-basins and their magnetic susceptibility was measured and calculated. The results of Kruskal–Wallis test and discriminant function analysis showed that magnetic susceptibility properties can be used as optimum set of tracers in the uncertainty mixing model. The results of Bayesian mixing model indicated that mean (uncertainty range) relative contribution of Sparan, Joyband and Boyoukchay are 92 (83.9-94.8), 2.8 (0.2-10.7), 5.7 (0.2- 10.5) percent, respectively. According to these results, the highest amount of sediment yield is related to Sparan sub-basin and these results could be used in soil conservation and management planning.

Water scarcity is a major and structural problem in arid and semi-arid regions across the world that greatly concerns environmental policy-makers. The problem of adjusting the demand exceeding the sustainable supply has been mainly tackled with demand policies, particularly through investment in water saving technology and promotion of irrigation efficiency programs. However, there have been very few evaluations of these programs and many of those that exist raise serious doubt about the programs’ effectiveness in reducing the consumptive use of water, due to the occurrence of the rebound effect. In this study, a sample of 243 farmers in Fars province who have the sprinkler irrigation system installed in their farms was interviewed to collect needed data for investigating the rebound effect using AHP and ordered logit regression model. The results indicated that 74.5 percent of sampled farmers have experienced medium to large rebound effect. It was also found that the amount of dry and fallow land during installation of sprinkler irrigation system have a positive relationship with the probability of occurrence of the rebound effect. Finally, the results of this study can be used to determine the probability of the rebound effect occurrence after installment of the sprinkler system for farms where data is available. For example, in the farms with farm features 24, probability of the rebound effect as a result of water saving measures at the low, medium and high levels are 0.4, 32 and 67.4 percent, respectively. Therefore, we must apply specific water conservation and efficiency practices in such farms based on a combined use of technical, economic, social and political tools to reduce pressure on scarce water supplies.

Treated wastewater may influence soil structure, porosity and as a consequence, soil saturated hydraulic conductivity. This study aims to assess the effect of wastewater on saturated hydraulic conductivity; and to determine the suitable soil solids fractal dimension to incorporate into the pedotransfer function by Rawls et al (1993) for estimation of saturated hydraulic conductivity (Ks). Soil saturated hydraulic conductivity was measured by disc permeameter. Soil particle fractal dimension was calculated from linearized forms of mass- time, mass- diameter and mass- diameter as modified by Kravchenko- Zhang (1998) relations. Wastewater irrigation for 13 years increased the saturated hydraulic conductivity three times, from 7 mm/hour to 21 mm/hour, but longer application of wastewater did not further increase it. Rawls et al (1993) pedotransfer produced acceptable and relatively close saturated hydraulic conductivity values to that of disc permeameter when fractal dimension obtained from the linearized forms of mass- diameter and Kravchenko- Zhang relations were used. Therefore, Rawls et al (1993) pedotransfer was capable of reflecting the effect of wastewater application on soil saturated hydraulic conductivity.
 

Landslide susceptibility mapping is essential for land use planning and decision-making especially in the mountainous areas. The main objective of present research is to produce landslide hazard zonation at Sarkhoun basin in Karoon basin using two statistical models such as an index of Shannon’s entropy and weight of evidence and to assess the obtained results. At the first stage, landslide locations were identified in the study area by interpretation of aerial photographs, image sattellites, and from field investigations and then landslide inventory map was created for study area. The landslide conditioning factors such as slope degree, slope aspect, altitude, lithology, land use,distance of road, distance of fault, distance of drainage, topographic wetness index (TWI), Convergence Index, and precipitation were extracted from the spatial database and they were digitized in GIS environment. With integrated variables, landslides were calculated in each variable class and ‎weighted in index of entropy and weight of evidence model. In the last, landslide hazard zonation map ‎were obtained with both of models. The results of landslide susceptibility mapps of both statistical models were indicated more than 70 percent the occurred landslides were located in very high and high zones that about half of the basin area (over 45 percent) constitute. Also, the results of both models together were revealed that land use, has the greatest impact on the occurred landslides. Resolution of the zones, based on the seed cell area index (SCAI) and frequency ratio (FR) were evaluated suitable for both statistical models. Finally, the ROC (receiver operating characteristic) curves for landslide susceptibility maps were drawn and the areas under the curve (AUC) were calculated. The verification results of both models were evaluated very well and showed that the index of entropy model (AUC=89%) performed slightly better than weight of evidence model (AUC=82%).

Bi-level drainage system is a type of underground drainage systems, in which adjacent drainage lines are installed at different depths. In the Hydraulics Laboratory, Ferdowsi University of Mashhad, a model was built, that include a cube tank 2 meters in length, width and height of 1 meters was made ​​of galvanized. In this model, two rows 20 cm apart from each other drains were installed. As drainage, a pipe of three layers to the outer diameter of 16 mm was made of PVC. Within this model of stratified soil was used as a soil layer of low permeability with a hydraulic conductivity of 1.15 cm per hour, thickness of 20 cm soil layer between two light soil layer with 30-cm thickness for bottom layer and 20 cm for the top layer with a hydraulic conductivity of 1.55 cm per hour. For accurate measurement of the water table Behavior in the soil at each point of the model, some piezometer distance of 10 cm from each other on the floor model was installed. After Outfit of model with blow-off valve, Experiments with a heavy irrigation for different intervals between depths of 30 and 50 cm were used in drainage and water table elevation values ​​as observed values ​​were extracted from the model. The results show that the values ​​obtained from Upadhyaya and Chauhan Equation only in small area of water table profiles, which include an area of between the two drainage, are consistent with observed and with a wider distance between deep and shallow drainage, time of drop in water table increased.

Dust deposition phenomenon is an important climatic and environmental issue in arid and semi-arid regions. The objective of this study was to examine important characteristics of atmospheric dust in Kerman as one of the major cities in arid areas of our country with high potential of dust production. Dust samples were collected monthly using glass traps installed on the roof of 35 one-story buildings in Kerman for 7 months from April 20 to Nov. 20, 2012. To compare the results of atmospheric dust with those of soil, 60 surface soil samples (0-10 cm) from outside Kerman and 35 soil samples from urban areas were also collected. Some physical and chemical characteristics such as pH, electrical conductivity, organic matter, calcium carbonate equivalent, and  particle size distribution were determined in dust and soil samples. The results of chemical analyses indicated that the amount of these properties is much higher than that in soils. Atmosphere dust particles appear to mainly originate from alkaline and saline soils surrounding the city of Kerman. Dust particle size distribution analysis further confirmed that dust particles have been transferred to Kerman city from medium to long distance areas.  Temporal variability in dust chemical properties indicates that the contribution of anthropogenic and natural sources to urban dust in Kerman has seasonal changes. Based on the results obtained, it is necessary to control dust production outside and inside the city and its distribution in populated areas employing proper management practices.

Mapping the spatial distribution of soil taxonomic classes is important for useful and effective use of soil and management decisions. Digital soil mapping (DSM) may have advantages over conventional soil mapping approaches as it may better capture observed spatial variability and reduce the need to aggregate soil types. A key component of any DSM activity is the method used to define the relationship between soil observations and environmental covariates. This study aims to compare multiple logistic regression models and covariate sets for predicting soil taxonomic classes in Bam district, Kerman province. The environmental covariates derived from digital elevation models, Landsat imagery, geomorphology map and soil unit map that were divided into two different sets: (1) variables derived from digital elevation models, remote sensing and geomorphology map, (2) variables derived from digital elevation model, remote sensing, geomorphology map and the soil map. Stratified sampling schemes were defined in 100000 hectares, and 126 soil profiles were excavated and described. The results of accuracy model showed that data set 2 increased accuracy of model including overall accuracy, kappa index, user accuracy and reliability of the producer. The results showed that the multiple logistic regression model can promote traditional soil mapping and it can be used to large group of other scientific fields.
 

Water quality assessment is important in late years coincide white decreas quantity it. The Zayande-Rood's Dam Lake is one of the important water resources that supplies drinking water for human populations in Isfahan, This lake also supplies water resources for agricultural sections of these provinces. Five points were determined as the sampling stations. Samplings were performed from May, 2013 to March, 2014 in seven steps, once every forty five days in for seasons (two times in each season). The water quality parameters (DO, NO₃, NO₂, EC, pH, hardness, TDS, NH₄, BOD5) were measured in all the stations and stages, and then water quality indexes were calculated. According to the results of this study, the water quality of the Zayande-Rood's Dam Lake estimated as good (50-100), with using WQI index. WQI index maximum was in summer (84.63) and minimum was in autumn (66.4). Considering the importance of the Zayande-rood's dam lake as a supplying resource of drinkable water of Isfahan. It seems that further attention in the lake watershed management is needed in order to protect water quality.