نشریه آب و خاک
سال بیست و هفتم شماره 2 (پیاپی 28، خرداد و تیر 1392)

The biodegradation of normal-hexadecane by bacteria is one of the important aspects of bioremediation. The aim of this study was to investigate degradation of normal hexadacane (with level of contamination، 2500 mg. kg-1) by Pseudomonas aeruginosa، Pseudomonas putida and native bacteria of contaminated regions in the presence of NPK (three types of fertilizer: urea with 46% nitrogen، ammonium phosphate with 21% nitrogen and 46% phosphor and potassium sulphate with 40% potassium) as nutritious source. The experiment was carried out as a completely randomized design (CRD) with factorial arrangement in three replications. Experimental factors included six levels of bacteria (Pseudomonas aeruginosa، Pseudomonas putida، three strains from contaminated regions Ahvaz، Sarakhs and Tehran and control)، three levels of fertilizers treatment (0 and 2 ton. ha-1 of NPK) and two levels of soil condition (sterile and non-sterile) at two times (30 and 60 days). Then، soil total organic carbon (TOC) as index for the degradation of normal hexadacane in samples was measured. The results showed that degradation of normal hexadecane in sterilized soil samples were higher than non sterilized soil samples. the highest degradation of normal hexadecane was observed in the presence of Sarakhs strain. The amount of degradation by this strain with nutritious source was 45% whereas this value was lower (one third) in the absence of NPK. Moreover، the results indicated that the amount of degradation by the bacteria increased with time. Biodegradation value in the presence of NPK was 4-fold higher compared to no-NPK treatment after 60 days.

This study was conducted to assess different chemical weathering indices and to evaluate the weathering rates of soils developed on volcanic (hornbelende andesite، pyroxene andesite and dacite) and plutonic (alkali granite، granodiorite، monzodiorite، syenite and pyroxene diorite) igneous rocks in the northwestern Iran. Representative soil profiles were described and soil samples were collected and analyzed for selected chemical and physical properties. Total concentrations of major elements and trace element (Zr، V، Ti and Y) were determined with ICP-OES and ICP-MS، respectively. Significant correlation coefficients were obtained between soil properties (clay percent، pedogenic iron and bulk density) and Ba، B/A، B/R، CIA، CIW، PIA، PWI and the WR chemical weathering indices. These indices are based on the ratio of a group of mobile oxides to one or more immobile oxides and are suitable for explaining the weathering rate of the soils developed on igneous rocks in this semiarid region. A-CN-K and MFW ternary plots showed that the soils developed on volcanic rocks (hornbelende andesite> pyroxene andesite> dacite) were more weathered than those on the plutonic parent rocks (alkali granite، granodiorite، monzodiorite، syenite، pyroxene diorite). Ba and CIA weathering indices predicted weathering trend such as MFW ternary plot، and it seems these two weathering indices are the most suitable weathering indices after W index (or MFW ternary plot) in this semiarid region. Ca، Na and K elements are presented in chemical weathering formulas of these two indices. These elements are in the feldspar minerals structures which are the most mineral in the earth crust.

In this research، stochastic goal programming is applied in water resource management. It is a multi-attribute decision support model which produces satisfactory solutions in uncertainty conditions. The satisfaction of beneficiary users and ecological impacts are investigated in this paper. Also، using sensitivity analysis، the effects of changes of parameters on the model outputs have been investigated. The stochastic goal programming model has been applied for Booshkan valley in the year 2009. Results show that the proposed model is capable to capture multiple objectives. In addition، having the risk parameters being defined، the decision maker can investigate different scenarios، based on different values for parameters.

Nayshabour plain in Khorasan Razavi with arid and semi-arid climate، have an important role in agricultural production by using groundwater resources. In this study، by using groundwater balance model the equations which are required for estimating water table variations is obtained for plain. afterwards since، there are too many variables in the objective function of water consumption (optimized crop pattern and intensification) a meta heuristic method which require less computation of effect while it is more efficient will be used. In this research PSO optimization algorithm (Particle Swarm Optimization) is used. Model results based on a normal year (2008) showed that can earn highest income from the aquifer with 30 percent reduced spring cultivation، and increased 30 percent of wheat، barley and calona. Among the spring crops، corn and tomato ratio to another crops have largest increase area. The results showed that can obtain 7500 (thousands rial /hec) more benefit with increasing 20،591 hectares to autumn crops and reduced 10،970 spring products

With increasing population and scarcity of fresh water،one of possible solutions is، using marginal waters (saline and sodic water). Using marginal waters should be taken into consideration and special studies. Since most processes related to soil and water، take place in unsaturated field condition، The purpose of this research is evaluation of saline and sodic water effect on diffusivity and unsaturated hydraulic conductivity. for this purpose، two soil types include loamy and sandy، two levels of SAR، 5 and 20، two levels of EC، 4 and 12 ds/m and distilled water were used. NaCl، CaCl2 and MgCl2 salts at Ca: Mg=2:1 were used to prepare treatments. Diffusivity was measured by one step out flow method at the suction of 15 bar. Unsaturated hydraulic conductivity calculated by using the diffusivity and the slope of the soil moisture charactristic curve. At both soils with increasing SAR and decreasing EC، diffusivity and unsaturated hydraulic conductivity decreased and this reduction was more at low moistures. Sandy soil was affected less than loamy soil. In comparison of treatments that cause the least and the most dispersion، diffusivity and hydraulic conductivity for loamy soil، decreased 100% and for sandy soil at low moistures، diffusivity and hydraulic conductivity decreased about 91% and 99%، respectively.

Water movement in unsaturated soils is commonly affected by hysteresis which is often ignored in the mathematical description of water flow and solute transport. In this study، hysteresis in soil water retention curve was quantified at lysimeter scale in sandy loam and silty loam soils and results of the Scott’s and Mualem’s models were compared. Three undisturbed soil monoliths (80 cm diameter by 105 cm height) were collected for each soil and water movement was studied for various boundary conditions. Monoliths were equipped with different measuring devices to monitor soil water contents، pressure heads، and outlet water fluxes. Four unsaturated steady state water flow experiments were conducted on each monolith. Hydraulic properties were determined by inverse method using the WAVE model and a global multilevel coordinate search inversion algorithm. First soil hydraulic parameters in the soil water retention and hydraulic conductivity functions were estimated neglecting hysteresis and compared with the functions obtained using approaches considering hysteresis. Hysteresis was simulated using the simple empirical model proposed by Scott and using the universal conceptual model of Mualem. Results of measured and modeling data indicated that hysteresis was observed in both soils. The effect of hysteresis was different on various components of water flow (i. e.، pressure head، water content، and water flux) in two studied soils. Water retention curves، pressure head، and water content were significantly influenced by hysteresis in both soils. The Scott''s model considerably improved pressure head estimates in the silty loam soil and Mualem''s model somewhat improved the soil water content estimates in the sandy loam soil. Outlet water fluxes in both soils were less sensitive to hysteresis. In general، the simple hysteretic model of Scott was more successful in studying hysteresis in both studied soils.

This research presents recent advances on morphodynamic modeling over gravel dunes. Experiments were carried out on flow over 4 different dunes developed in 12m flume at Institute of Hydraulic Engineering and Water Resource Management of Technical University of Graz، Austria. Dunes are developed in the height of 4،6 and 8 cm and in wavelength of 1m with 2 different particle sizes (6 and 13 mm) and also two different lee angles (38 and 8 degree). The separation of flow over gravel fixed dunes is investigated by Acoustic Doppler Velocimetry (ADV) and Particle Image Velocimetry (PIV) and to compare the experimental results with numerical models over dunes، the 3D numerical model (SSIIM) is applied in this study. The results show that for the same two dunes under the same velocity but different flow depths، larger separation occurs under lower flow depths and a decrease in dune height causes a reduction in length of separation. Moreover the separation zone has a strong relation with lee angle and in the situation of low lee angle no flow separation was detected. Finally the result reveal that numerical model successfully simulate flow over dune in compared with ADV and PIV data. Although ADV application near the bed indicates probably weak performance for high discharge and low water depth of dune No. 4، PIV results present more agreement with the numerical model in this region.

One of the applicable ways for simulation and forecasting hydrological processes is time series modeling. An important problem in forecasting hydrological data using time series is generating stochastic data. Any changes in stochastic series will change generating data. In this study nonlinear ARCH model presented in order to modeling and generating stochastic component of time series. After combing ARCH model with nonlinear bilinear model، BL-ARCH model suggested to forecasting river flow discharge. Daily river flow of Shahar-Chai River located in the west of Urmia Lake and West Azarbaijan province have been used for data analysis and 11 years forecasting. As results shown suggested model with 4. 52 error has better than bilinear model with 6. 77 error. So this model can be used for short-time river flow forecasting specially daily series.

Microbial reduction is an important process that affects properties of ferric clay mineralas and iron biogeochemical cycling in natural environments. Oxyhydroxides and phyllosilicates are two major sources of iron in soils، rocks and sediments that potentially have ability to bioreduced over the time. In this study، comparison of bioreduction in two main sources of iron (oxides and phyllosilicates) in the presence of Shewanella sp was carried out. For this purpose an experiment was conducted under laboratory conditions in the form of a completely randomized design with 16 treatments and 3 replications. Treatments included bioreduction of goethite، hematite and two type of nontronite with and without electron transfer (AQS) and controls (all mentioned treatments in the absence of Shewanella sp). The results revealed that bioreduction in goethite، hematite and two type of nontronite increased in the presence of AQS. The extent of reduction in the presence of AQS was 21%، 9%، 3% and 8. 7% in NAu-2، NAu-1، hematite and goethite respectively. These results have shown when iron oxides (goethite and hematite) and iron silicates are the dominant form of ferric iron in soils and subsurface sediments، Shewanella sp can survive and produce significant amounts of Fe (II). In the identical conditions of bioreduction (concentration of electron donor and acceptor and equal number of bacterial cell) size and surface area of mineral play an important role in efficiency of bioreduction.

The study of mountainous rivers is recently considered by hydraulic researchers. Ten cross sections of a cobble-bed river، Behesht Abad، located in the central Iran were applied in this study. The distribution of velocity profile in cobble-bed and accuracy of two-point method to estimate the parameters of mean velocity and shear velocity were investigated and then the values of flow resistance were evaluated. Shear velocity was calculated by two-point method، and velocity profile and the results were compared by the parabolic and the boundary layer characteristics methods to predict flow resistance function. Results reveal that velocity profiles present S-shape and logarithm distributions. Also the values of mean velocity، shear velocity and flow resistance function calculated by two-point method can be presented with 94. 6، 85. 6 and 84 per cent accuracy، respectively. The results of this study can be extended to apply and to predict flow resistance for other mountainous rivers in Iran.

Sand dunes movement is one of the critical processes of desertification. Mulching is one of the methods of sand movement control. Oil mulches have been used in Iran. Because of high cost and negative environmental impacts of oil mulches، changes in mulch type sand mulching methods is vital. Therefore، in this research different combinations of clay and lime were used as stabilizer. Sandy soil from the Yazd-Ardakan plain is used as bed treatment and clay particles (taken from Meybod area) were used as mulch in this research. The treatments were prepared using different ratios of the above mentioned materials. One liter of water was added to the each mulch combination and was sprinkled on the plot of 100 cm (length) × 30 cm (width) × 4 cm (height) sand. A completely randomized design is used as research plan with three repeating. Physical parameters، such as thickness، compressive strength، impact resistance and abrasion resistance which are created by mulches، and wind erodibility of the treatment were measured. The measured data were analyzed using SPSS software. Results show that the measured compressive strength، impact resistance and abrasion resistance of the clay–lime mulch is increase in the ratio of 200 gr clay and 10 gr lime in one liter of water.

Nowadays، accurate estimation of evaporation as one of the important elements of hydrological cycle can play an important role in sustainable development and optimal water resources management of the countries facing water crisis. Up to now، empirical methods and formulas on estimation of non-linear and complex process of daily pan evaporation have been developed that is of uncertainty. These methods and formulas do not have high accuracy and also access to their input parameters is difficult or their measurement requires high cost and time. In this study، performances of two non-linear models of NN-ARX and ANFIS have been evaluated to estimate daily pan evaporation under arid and hot climate conditions including dry and warm climate (Iranshahr)، dry and coastal warm (Chahbahar)، and semi-arid and warm temperate (Saravan). For this purpose، the best combination of model inputs was selected by using Genetic Algorithm embedded in Gama Test software for each of Synoptic stations located in these regions for the 5years period (2005-2010)، then daily pan evaporation was estimated by using NN-ARX and ANFIS models. By employing the statistical criteria including R2، RMSE and MAE، performances of ANFIS model with three Gaussian membership functions and NN-ARX model were evaluated for each of the selective Synoptic stations. The obtained results indicate the accuracy of ANFIS model is higher than the one of NN-ARX model in estimating daily pan evaporation in different climatic conditions.

Soil pollution by heavy metals from the manufacturing process due to metal smelting plants closely related to human health is very important. Given the importance of the province to industrial and agricultural activities، this study was conducted to explore the vertical and horizontal variability of lead and nickcl metals in contaminated soils around the Zobahan melting factory، in nearby of Isfahan city. For this purpose، 202 profiles were dug and described in the green landscapes of Zobahan industrial site by a manner of gird sampling method. Five hundred soil samples were taken from depths of 0–30، 60–90، and 120–150 cm. Conccntration of total lead (Pb) and nickel (Ni) were measured in the soil samples. To explore the vertical distribution of selected metals، the mean values of Ni and Pb were compared statistically. The horizontal variability of selected metals was evaluated by variography analysis and the spatial distributions of them were constructed by kriging method. The overall results of study showed that Pb content in surface horizons is controlled by industrial activity، otherwise the concentration of Ni mainly attributed to parent material.

Phytoremediation is one of the lowest-cost methods for remediation of soils contaminated with heavy metals. This study was conducted to investigate the phytoremediation potential of corn and canola، grown under single and mixed culture systems. Thus، a pot experiment was carried out on a calcareous soil contaminated by Pb and Zn. Treatments included single culture of corn، single culture of canola and mixed culture of corn and canola. Results showed that bioavailability of metals، lead، zinc، nickel and copper increased with decreasing soil pH and increasing DOC as influenced by root activity. Root uptake of metals; lead، zinc، copper and nickel in mixed culture، was more than that of in canola and lower than that of in corn. Zinc and nickel uptake by shoots of canola and mixed culture، were more than corn. Also، the results concerning the uptake of metals in the total biomass (sum of roots and shoots) showed uptake of copper and nickel in corn was more than mixed culture and it was more than canola while، uptake of lead and zinc in corn and mixed culture was more than canola. Also، the total yield of corn and canola in mixed culture increased. Therefore، it seems use of mixed culture system may extract metals، zinc and nickel more than corn، and copper more than canola، in single culture systems.

Based on limited water resources، increasing population، the need for high volume production and waste disposal، it is necessary to increase the reuse of wastewater. Artificial recharge using one of the most important methods of wastewater re-use of this resource is valuable. Necessary in order to utilization of artificial recharge system was conducted. In order to simulate the physical conditions of artificial recharge ponds PVC cylindrical column of diameter 30 cm and height of 250 cm was used. Columns filled by Sandy loam soil and Mahdasht Alborz Province treated wastewater was used for artificial recharge system in the College of Agriculture، Tehran University. Two strategies using geotextile lining and coating materials are coarse debris on the soil surface and a bare soil، water infiltration into the soil to improve the approach was evaluated in terms of permanently flooded. Values of BOD5، COD coliform، fecal coliform، nitrates and phosphorus inputs and outputs of the column effluent were measured. The results indicate the high efficiency of columns of soil، covered with geotextile، the amounts of percentage removal of BOD5، COD، coliform، fecal coliform and phosphorus، average 84/7، 77، 99/5، 99/7 and 79/9 and efficiency of all columns in the nitrate removal was low. Using geotextile cover and building materials in addition to reducing transport emissions، the use of the soil as well as the filter increases. Also due to its low cost and ease of preparation، may change or modify these materials to improve soil penetration.

The downward flow to the drain pipe، has a greater influence on the movement of soil particles toward drain envelope as compared with the horizontaland radialflow. In this study، by installing of a singular subsurface drainage systemconsisting of threedrain pipeswith drain spacing of 20 m and drain depth of 1. 5 m، in one hectare field of Sari Agricultural Sciences and Natural ResourcesUniversity، the effects of the elimination of downward flow to the drain pipe was investigated on the water table level and drainage flow. Prevention of direct entry of the vertical flow into drain pipe was performed by placing a layer ofplastic coveron the sand envelope of themiddle drain pipe. Water table level fluctuations were measured in holes which were dug in each drain trench and at 0. 5، 1. 5، 5 and 10 m spacing apart from each drain at intervals of 5، 15، 25، 35، 45، and 55 meters from collector ditch. Water table depth and drain discharge were measured from April 21 to December 21، 2011. The average drainage discharge fromno plastic drain (drain A) was more than corresponding value for plastic covered drain pipe (drain B) about 12 % and there was a significant difference (p=0. 05) between drainage water volume of drains A and B. The average depth of water table levels within the trench of drain A was 9. 1 cm more than the corresponding water table depth of drain B. Also، the average depths ofwater table in the 0. 5، 1. 5، and 5 m spacing apart drain A were approximately 5. 2، 2. 9، and 0. 05 m higher than of thosevalues of drain B. Sediment load of drain A was 74% more than that of drain B،indicating the considerable role of the inflow to drain from its upper part on the consequent sediment transport into drain pipes.

Biofertilizers can be used as complementary in sustainable agriculture. The main target of this study was effects of nitrogen and phosphorus fertilizers and chemical fertilizers on wheat yield and yield components in two soil types. Experimental design as the factorial formed completely randomized design with three replications was executed. Experiment Factors included two soil types (sandy loam and clay loam) and 9 fertilizer treatments. For the experiment implementation used 100 gram per hectare of Nitrokara (Azorhizobium caulinodans) and Barvar 3 phosphorus (Pseudomonas putida، Strain P13، Pantoea agglomerans، Strain P5 and Pseudomonas putida، Strain MC1) biofertilizers in single and combined forms by method of seed inoculation. The results showed positive effects of clay loam type and inoculation of two biofertilizer types especially in the presence of 50% of chemical fertilizers on shoot dry weight، root dry weight، number of grains per spike، 1000 grain weight and wheat grain yield. The results showed 100% chemical fertilizer and phosphorus biofertilizer in combination with 50 % of chemical fertilizer treatments showed the highest effect in most characteristics and control treatment showed the lowest effect in this characteristics. Nitrokara biofertilizer in combination with 50% of chemical fertilizer had the maximum 1000 grain weight. Phosphorus biofertilizer in combination with 50% of chemical fertilizer on wheat yield and yield components showed a better effect than Nitrokara biofertilizer. The results of this research showed by combining biological and chemical fertilizers can reduce consumption of chemical fertilizers.

This study focused on the effect of organic manures as well as potassium fertilizer on some soil properties and onion yield at the field condition. The experiments were carried out as factorial in a randomized complete block design with three replications. The treatments were poultry manure (10 t ha-1)، alfalfa residue (10 t ha-1) and control each together with two levels of potassium fertilizer as K2O (0 and 250 kg ha-1). The results showed that application of poultry manure and alfalfa residue resulted in yield increasing about 57. 7 and 40. 9 % in comparison to the control، respectively. On average، the onion yield for the potassium treatment was 7. 8 % higher than for the untreated one. The application of poultry manure and alfalfa residue increased final infiltration rate 73. 2 and 56. 1 %، respectively. Inversely، potassium fertilizer caused a significant reduction in the final infiltration rate. Moreover، application of organic manures particularly poultry manure، significant increases in saturated moisture، porosity، EC، organic carbon and available phosphorous and decrease in bulk density and pH was observed، while potassium only increased soil EC، significantly. Application of poultry manure and alfalfa residue increased soil organic carbon 129. 8 and 80. 2 % and available phosphorous 104. 8 and 51. 9 %، respectively. Among different soil properties، organic carbon showed the highest influence on yield increase.