نشریه دانش آب و خاک
سال بیست و هفتم شماره 4 (زمستان 1396)

Efficiency of a trickle irrigation system depends on the hydraulic performance of drippers and the design criteria. Lack of attention to drippers problems may cause reduction in water distribution uniformity, increasing time of system working, permanent drippers replacing, increasing the cost of system and even system failure and returning to traditional systems. So, in this study, the performances of drippers at three fields including Oman Samani, Fadak and Emamieh at the sides of Zayandehroud river in Chaharmahal and Bakhtiari Province were evaluated.The results showed that indices the of uniformity distribution ofthe Omman Samani, Fadak and Emamiehwere 56.8, 95 and 69.3 percents respectively. The discharge variations of drippers of Omman Samani, Emamieh fields were mainly due to undesirable pressure, clogging of drippers and replacing existing drippers by non-expertized farmers. The hydraulic coefficients of variations of drippers at Omman Samani, Emamieh andFadak fields were obtained with the values of 43.7, 28.2 and 6.3, respectively that showed an unsuitable hydraulic design of the first two fields and a proper design of the last one. overall, the performances of Micro Flapper and Dripper emitters at the Omman Samani and Emamieh fields were undesirable and the Netafim one at the Fadak field had an excellent performance.

In this study, effects of heavy metal of chromium on microbial and eco physiological indices of soil in presence of vermicompost were evaluated using a complete randomized design. This experiment was carried out in five levels of chromium (0, 100, 200, 300 and 400 mg Cr kg-1 soil from potassium dichromate) and seven incubation periods (5, 30,60,90,100,110 and 120 days) in three replicates and for decreasing the adverse effects of pollutant in soil, in the 90th day, vermicompost was added to all of the treatments. At the end of each period, dehydrogenase enzyme activity, basal respiration and microbial biomass carbon as microbial indices and also metabolic and microbial quotient as eco physiological indices were measured. The results showed that with increasing chromium concentration in soil, the microbial indices were decreased up to the 90th day. Dehydrogenase enzyme activity decreased by 100 percent in concentrations of 100 mg Cr kg- and then it was increased, therefore application of the vermicompost compensated the adverse effects of the pollutant. Metabolic quotient in concentration of 300 mg kg- Cr the 90th day reached to 5.43 and then decreased to 0.164 in the 100th day. This decrease happened in concentration of 400 mg kg- Cr, severely. By adding organic matter, the microbial quotient increased 56 and 44 percent in control and in the highest concentration of the chromium respectively. Based on result of this research, in concentrations higher than 100 mg Cr kg- in soil negative effects of the metal on microbial indices was revealed and usage of vermicompost in improvement of this indices in presence of chromium was efficient.

In this study, the depth spreading coefficient in surface discharge of dense jet flow from convergent and inclined rectangular channels into deep and stagnant ambient have been investigated. Therefore, the experiments were done in the hydraulic laboratory of Shahid Chamran University on a flume with 3.2-meter length, 0.6-meter width and 0.9-meter depth. For purposes of this research, the jet flow was injected with three different flow rates and concentrations. Also, for surface discharge of the jet flow, a rectangular channel with floor width of 6 cm and four different convergence angles of 12.5, 25, 45 and 90 degrees was used. The discharge channel was installed in three slopes of 0, 4 and 8 percent in order to be the surface discharge of the jet fluid tangent to the ambient water surface. After conducting the tests, the data were analyzed using the routing process of the prepared images. Then, the coefficients of depth spreading were calculated and the results were extracted. The results showed that increasing the channel slope, reducing the convergence angle and increasing densimetric Froude number increased the depth spreading coefficient. Quantitatively, the results showed that change of channel slope from 0 to 8 percent caused an increase in the spreading coefficient up to 34 percent and the change of convergence angle from 90 to 12.5 degrees caused an increase up to 27 percent. Finally, a statistical relationship between spreading coefficient and the other relevant parameters was extracted that its root mean square error was obtained 0.024.

Detection and evaluation of the actual amount of water used for different agricultural products is of paramount importance that such an assessment can identify and provide appropriate solutions to reduce water consumption in agriculture very effectively. In this research, to evaluate the agricultural products from view point of irrigation and water consumption, the Relative Irrigation Supply (RIS) as an indicator that shows accuracy of excessive irrigation when it value is more than 1, else when it value be less than 1 the consumed water is less than irrigation requirement and water footprint indicators (WF) were used for main crops in Urmia lake basin. The water footprint of products was estimated for two component of blue water (WF blue) and green water (WF green). Then actual water footprint was calculated by applying irrigation efficiency. The results showed that the maximum amount of water footprint was for wheat in Maragheh station, in which the blue, green and actual blue water footprints were 1779.77, 729.96 and 2150.91 m3 ton-1, respectively. Also the lowest water footprint was for corn in Sarab station in which the blue, green and actual blue water footprint were 99.86 m3 ton-1, 19.75 m3 ton-1 and 165.28 m3 ton-1 respectively. The Relative Irrigation Supply index (RIS) values were determined for main crops in seven meteorological stations of Lake Urmia basin and this index showed an excessive irrigation for all crops. While alfalfa and wheat, had less amount of RIS than other products.

In order to determine the best water - salt - the quality parameters (fiber length uniformity, fiber, fiber tension, fiber strength, fineness of fiber, protein and oil content of seed cotton) in Varamin and Khordad Cultivars of Cotton research project examines the impact of salinity and water levels irrigation on yield and yield components and quality of two varieties of cotton were conducted in Birjand climate. It forms a simple linear function, Cobb-Douglas, quadratic and transcendental were used. First results tables and statistics functions F coefficients showed that all functions mentioned above and were able to estimate the parameters of the fiber length and uniformity, have. The coefficients of the regression lines are plotted equations and graphs contained in the Student t-statistic regression line between the measured and predicted values ​​confirmed this. So the next step was to rank and identify the best among them. The purpose of the five statistical parameters Root Mean Square Error (RMSE), Coefficient of Determination (CD), modeling efficiency (EF), the maximum error (ME) and coefficient of residual (CRM) was used. The results showed that the parameters of both cultivars Khordad and Varamin cotton fiber length and uniformity, can function as a quadratic function is superior to the other functions in the present climate of Birjand. The results showed that none of the functions could not reasonably estimate the parameters of the fiber tension, fiber strength, fiber fineness, cotton seed protein and oil content have been ignored and that's why the ratings. Resulte showed that both cultivars of Varamin and Khordad parameters for fiber length uniformity, quadratic function can be expressed as function of the regional climate Birjand superior to other functions will be presented.

Due to the insufficient suitable agricultural land and the large extent of saline-sodic soil across the world, the reclamation of the salt affected soils is necessary. Studies indicate that the addition of biochars to the soils improves their qualities, increases crop yield, and reduces salinity stresses. In the present study, the effects of adding various biochars on some chemical characteristics, including the concentration of soluble cations and anions of saline-sodic soil with clay-loam texture, which was taken from the Kafoun region in Mazandaran province, were investigated. Several kinds of simple and acidic biochars were produced from agricultural residues (rice straw) and wood factory waste (dicer) at 300 ° C and added to saline-sodic soil in three levels 0, (2.5, and 5%). The results showed that the rice straw biochar reduced the soil pH more than the biochar obtained from dicer. It was also understood that dicer biochar reduced the amount of soil EC, SAR, soluble sodium, potassium, calcium, and chloride. However, the rice straw biochar, acidic rice straw biochar, and acidic dicer biochar increased the amounts of those criteria and elements. Ultimately, it can be concluded that only the dicer biochar should be added to saline- sodic soil, in the absence of leaching and drainage.

Knowledge about different forms of Cu and determining the amount of each one provides useful information for evaluation of soil Cu status and also understanding soil Cu chemistry. To obtain such information, the amount and distribution of Cu in different fractions of 21 composite soil samples of East Azerbaijan Province were determined by modified sequential extraction procedure introduced by Singh et al and the relationships of these fractions with each other and with soil properties were also investigated. According to the results, total Cu concentrations of soils ranged from 21.50 to 90.57 mg/kg with a mean value of 37 mg/kg. Sand and silt percentage with Cu associated with amorphous Fe oxides had significant correlation. Silt content had significant correlation with organically copper and amorphous Fe oxides bounded Cu. Both calcium carbonate equivalent and active calcium carbonate equivalent had significant correlation with exchangeable copper. Among the copper forms, Cu-Ex, Cu-CFeOX and total Cu had positive and significant relations with soluble Cu and among them Cu-CFeOX had highest correlation coefficient value (r =0.53*). The order of various forms of soil Cu was found to be as follows: Residual copper (Cu-Res) > crystalline Fe oxides bound (Cu-CFeOX) > amorphous Fe oxides bound (Cu-AFeox) > organically bound (Cu-OM) > carbonates bound (Cu-Car) > soluble exchangeable (Cu-Ex) > Mn oxide bound (Cu-Mnox). In this study a significant correlation was also observed between some forms of Cu, which is presumably a reflection of the existence of a dynamic relation between them in soil.

Due to advection phenomenon, energy balance in vegetation covered field's changes and some additional energy is transferred from the barren lands to vegetation covered sites by air sensible heat flux. This phenomenon increases the evapotranspiration. The present study was conducted to investigate the advection occurrence in the field of maize as a spring crop, and winter wheat as a fall crop at the Agriculture Faculty Research Station of Tabriz University. Mentioned crops for were planted in a 1.6 hectares’ farm, equipped with a lysimeter at its middle, for two years. These crop's evapotranspiration was measured by the lysimeter during the growing season of each plant. The advection phenomenon occurrence was investigated using the methods of energy balance in the field surface, Priestly-Taylor coefficient, the ratio of evapotranspiration obtained from advection energy to vegetation surface evapotranspiration (Rad) and Bowen's ratio () on different days after planting of each crop. Observation data of the temperature showed that there was a sensible heat gradient between the lysimeter and surrounding areas. Negative values of the sensible heat flux, Rad and Bowen ratio on some days of plants growing season showed that the advection extra energy had affected the crops evapotranspiration values. Results showed that the advection effect on maize evapotranspiration was more than that on wheat evapotranspiration. In the study region except of regional advection, local advection could be occurred due to small size of cropped fields, different irrigation schedule and depth of adjacent farms, and fallow duration of some farms.

Nowadays, water scarcity and frequent occurrence of droughts in Middle East countries including Iran create many problems for population of these regions. Drying off Salty Lake Urmia and its consequences is very important form the Iran and Middle East water industries. The main reason of Lake Urmia crisis is streamflow reduction of rivers leading to the lake due to excessive extraction of water resources in recent decades. Since the river-aquifer is a system with two interrelated elements, therefore, investigation of streamflow coefficient versus groundwater table relationship is necessary for streamflow forecasting. In this study, instantaneous runoff coefficient (events) and water table fluctuation relationship was checked out in two hydrometric stations located at the beginning and ending sections of Ghaleh-Chayriver which discharges water to the Lake Urmia. Then, the mechanism of stream flow loss (flow reduction process) due to water level draw down was studied along the river profiles. The results of this study showed a direct relation between the runoff coefficient and the water table level. Correlation coefficient value (R) between these two factors was observed 0.9 for Yengejeh station located at the beginning section of the river and 0.84 for Shishavan station at the ending section of river. Evaluating the stream flow losses trend along the river indicates that this flow has been naturally diverted to saturate the transition zone (the zone between the water table level and stream bed).

In alluvial streams, roughness coefficient (RC) is one of the essential parameters which should be considered in study of sediment flows in rivers. The height of bedforms directly affects RC based on flow hydraulic conditions.In this research some experiments were done to evaluate the effects of convergence transition on the roughness coefficient. Three kind of transitions with different angles of inflow direction to the flume wall were used (5, 10 and 15 degrees). In each transition after the completion of the test and slow draw down of the water level, the sediment profile of the bed was recorded and the bedform height was determined. The results showed that the channel width reduction in transitions had a significant effect firstly on the ripple bedform height and secondly on the RC of the flow. The Froud number in the all of experiments was in the range of 0.2-1.05. With increase of the transition angle from 5 to 15 degrees, at the discharge of 10 L S-1, the RC was reduced about 17.5 percent and in the discharge of 14 L S-1 it was increased about 11 percent.

There is a limited research in the literature on the vulnerability of confined aquifers. In this research as the first one in Iran, the confined aquifer of Tabriz plain has been investigated to evaluate the vulnerablity related to the contaminantion from surface sources. This aquifer is subjected to contamination by various pollutants which may be released from urban areas, industries and farmlands. At first, confined aquifer of the plain has been delineated from unconfined aquifer using study of well information and The hydrochemical Characteristics of aquifer. Five hydrogeological parameters (piezometric level, aquifer media, hydraulic conductivity, distance to confind-unconfined boundary, and pollution potential index of unconfined aquifer) were introduced as the main parameters that impact on the vulnerability of confined aquifers. These parameters were linearly combined using weighted overlay technique to achieve the final index to reflect the vulnerability of the aquifer. The results revealed a vulnerability index value between 47 to 202 indicated that the east and northeast parts of the aquifer had a high vulnerability condition while the west and south parts of the study area had a low and low to moderate risk of pollution. Nitrate concentration distribution map confirmed the results of the vulnerability assessmentand comparing the spatial relationship between the land use and vulnerability zoning maps showed that the most areas of the confined aquifer were under the threat of anthropogenic contaminants. It is recommended to use artificial neural network and fuzzy logic techniqus to verificate the results of this model. In areas with high vulnerability, severe monitoring should be exerted in order to avoidence of pollution from industrial plants, also establishment of new industrial units in the vulnerable zones should be prevented.

For reducing the destruction of water resources and for resolving the future populations, needs for food, the replacement of rainfed farming instead of water farming will be inevitable. According to the importance of the agricultural sector, determining indices to identify the fertile lands for cultivation of rainfed wheat is essential. For this purpose, to evaluate the yield of rainfed crop at the East part of Lake Urmia, two indices Interval Ratio and Partial Interval Ratio, for identification of the eligible areas for rainfed farming, were introduced using irrigation depth, irrigationintervals, and daily rainfall in corresponding with the time intervals. Clustering of the indices and yield of rainfed area were done with a K-means method. Regionalization of the obtained clusters for the yield and indices were done in GIS environment. Results of the regionalization showed that between the two introduced indices the Partial Interval Ratio index has the more compatibility to region reality, So the Partial Interval Ratio index selected for evaluating the rainfed regions. To identify the fertile rainfed regions of crop yield, the isoline of the yield of rainfed and index (Partial Interval Ratio index) was used. The results showed that in the northwest and central parts of the studied area the yield and Partial Interval Ratio index were increased, which indicated the good potential of rainfed farming in these areas. Therefor the fertile regions based on the introduced index were at the central and northwest parts of the studied area.

Iran has been considered as one of the arid and semi-arid regions of the world in terms of climatic conditions. Limited water resources and inappropriate management of them has fed the agricultural sector with significant challenges. Efficient usage of water in the field, requires accurate estimation of the plant’s water consumption. So far, many studies have been conducted in order to provide new methods for estimation of the reference evapotranspiration (ET0) using intelligent systems. In this study, in addition to evaluation of the efficiency of genetic programming (GP), other models are provided for estimation of evapotranspiration, which are using the minimum amount of meteorological variables. For this purpose, by use of the stepwise regression method, input variables of GP are selected among 7 meteorological variables (i.e., average air temperature, maximum air temperature, minimum air temperature, relative humidity, wind speed at two meters’ height, sunshine hours, and solar radiation). Moreover, eight conventional empirical models are used to compare the performance of empirical models with GP models in the estimation of reference evapotranspiration. In this study, the FAO Penman-Montieth method is considered as the reference method in evaluation of the performances of GP and empirical models. The obtained results show that the GP models have higher accuracy than empirical models. Finally for improving the performance of obtained results, the Bayesian model averaged method is used to combine the results of GP models and to determine their uncertainty bands.

Petroleum aromatic hydrocarbons are important sources of soil and environmental pollution in our country especially around oil refineries. In order to remove these pollutants, biological methods using native microorganisms of oil contaminated soils are preferred because of their cheapness and availability. Existing soil microorganisms use these hydrocarbons as carbon and energy sources and finally produce water, CO2, biomass and harmless materials. In the present study, the sampling was conducted from different unpolluted soils of Tabriz city and oil-polluted soils of Tabriz Petroleum Refinery. The soil suspensions were cultured in YGM and SCA media and finally, 100 microbial isolates were obtained. Phenanthrene at a rate of 1000 mg/L was added to the MHB medium and then the fixed amounts of these bacterial isolates were added separately. They were incubated in shaker with 130 rpm, at 28˚C for one week. The rate of phenanthrene destruction was evaluated by spectro photometery. Thereafter the reliability of primary aromatic compounds was assayed by TLC method. Eighty-seven bacterial isolates with phenanthrene destruction rates of 3.2-93.8% were selected. Some secondary metabolites originated from destruction of hydrocarbons were subjected to the GC-Mass analysis. Some non- toxic mediatory substances were identified as result of phenanthrene biological degradation. Bacterial isolates possessing of phenanthrene degradation up to 50% were identified. By improving the growth and proliferation of effective bacteria it will be possible to remediate polluted soils from PAHs in industrial pilots.

Salinity stress is recognized as an important constraint that limits agricultural production especially in arid and semi-arid regions around the world. Application of microorganisms such as Trichoderma isolates and silicon is an effective and easily adaptive strategy to reduce the environmental stresses like salinity. In order to evaluate silicon effect and Trichoderma virens inoculation on growth and some properties of wheat grown under saline condition a factorial experiment with complete randomized design was arranged. The factors included two levels of fungus (with and without inoculation), two levels of Si (0 and 1.5 mM), as Na2SiO3, and three levels of salt (0, 18 and 31 Meq kg-1 salt supplied as NaCl, CaCl2 and MgCl2 with 3:2:1 proportion, equivalent to soil saturated electrical conductivity (ECe) amounts of (3.2-3.4), (6.9-7.2) and (9.5-9.9) dS m-1, respectively). The results showed a negative effect of salt stress on wheat growth. Both 18 and 31 Meq kg-1 of the added salts caused significant reductions (p

In order to the evaluation of the effect of mycorrhizal fungi, different sources and levels of iron on growth and nutrients uptake in Mexican lime (Citrus aurantifolia L) (one of the important rootstock in citrus growing regions in south of Iran), a greenhouse experiments were conducted with factorial arrangement in a completely randomized design with three factors and four replications. Treatments consisted of three levels of mycorhizal fungus (without fungal inoculation, inoculation with Rhizophagus intraradices, inoculation with Glomus versiforme), two sources of iron (iron chelate, iron solphate), and three iron levels (0, 7.5, 15 mgkg-1 Fe). The results indicated that co-application of mycorrhizal fungal species and iron sources was improved plant growth charactrices and the concentration of nitrogen, potassium, iron, zinc, copper, and manganese. In the treatments inoculated with mycorrhizal fungi, with an increase in iron levels, the nutrient concentrations of iron, zinc, copper and manganese in soil were increased, likely because of the balancing effect of mycorrhizal symbiosis on nutrient concentrations in plants. It seemed that co-application treatments of fungi with iron sulphate were effective on different growth indices of plant and could reduce iron chelate consumption or be used instead of it.

In most areas, groundwater resources play a major role in water supply of the needs in parts of agriculture, drinking and industry. The scope of studied area of Ardebil is 4804.7 square kilometers and the extent of Ardebil plain in this region is 820 square kilometers. This aquifer feeds through the direct infiltration of surface downfalls, returning water from agriculture, drinking and industry expenditures and also the underground drains. In this study, the basic methods of the analysis of time series includes models of autoregressive (AR), moving average (MA) and the combination of autoregressive and moving average (ARMA) were implemented on the data and the best model was chosen by using the test of Akaike coefficient data autocorrelation functions. Then, it was observed the results of model AR (2) are better than other models according to these tests and coefficients. Finally, a prediction was accomplished for a period of thirty years by using the same model. The results of the predicted values by time series shows a reduction of approximately 11 meters into the current situation of water table of aquifer in the case of constant consumption patterns and also without change in the procedure of the feeding in the aquifer during the next thirty years. The decision to manage the groundwater in this area is required, due to the restriction of the resources and the drawdown of water table and the particular sensitivity of this region about drinking water supply in the coming years.

For a cost-effective design of wave screen, an accurate estimation of dynamic pressure and wave force is needed. In This study investigates the dynamic pressure action on elements of wave screen. The wave screen consists of several horizontal pipes with constant distance between them. This wave screen provides convection and interchanges of seawater within the harbor district, and makes available wave energy absorption effectively. The experimens were done on a wave screen under collision of regular waves with 3 heights and 6 periods of waves at a constant water depth of 0.6 m. Also 3 different diameters were considered for wave screen pipes. Dynamic pressures distributions along and around the pipes were measured by the pressure transducers. The results indicated that with increasing the porosity, the pressure difference was decreased and with increasing of the incident wave height, pressure fluctuation for different porosity was increased. Furthermore, the maximum dynamic pressure fluctuation was occurred at the angle more than 45°.

In order to investigate the effect of nitrogen and silicon on some physiological Properties of the pistachio seedlings (Pistacia vera L. cv. Badami Zarand) in saline conditions, a factorial experiment was carried out in a completely randomized design with three replications under greenhouse conditions. Treatments consisted of nitrogen (0, 60 and 120 mg N kg-1 soil as NH4NO3), silicon (0, 1 and 2 mM as H4SiO4) and salinity (0, 1500 and 3000 mg NaCl and CaCl2 kg-1 soil with the ratio of two to one respectively) that at the end of the experiment created average salinity of 0.3, 9.7 and 20.9 dSm-1, respectively.Results showed that the salinity stress decreased the leaf relative water content and increased the electrolyte leakage, but application of 2 mM silicon increased the leaf relative water content by 28 percent and decreased the electrolyte leakage. Also combined application of 60 mg N kg-1 soil and 2 mM silicon increased the concentration of proline 36 percent compared to the control. The highest amount of soluble sugars in saline conditions was achieved with the application of 2 mM Silicon that increased more than 2 folds compared to the control. Although salinity stress decreased the shoot Fe, Mn and Zn concentrations significantiy, but application of the nitrogen and silicon increased the concentration of these elements significantiy. According to the results of this experiment, it is concluded that the combined application of nitrogen and silicon in saline conditions through improving the physiological Properties increased the ability of pistachio seedlings in tolerance to salinity stress.

Soil is a diverse, dynamic and heterogeneous system and investigation of its spatial and temporal changes is essential for systematic management of natural resources. In this study the spatial variabilities of some physical and chemical properties of the soil affected with aspect in Kiasar rangelands were investigated. Two sampling sites were selected with the same climatic level, slope, elevation and lithology but with different slope aspect. A sampling grid with 400 m2 cells was established in each site and 50 soil samples were collected from 0-30 cm soil depth. Soil properties including pH, caco3, total nitrogen, organic carbon, percent of silt, clay, sand and moisture were measured in the laboratory. Then data were normalized and applied for the statistical and geostatistical analyses. Results of the t test showed that organic carbon in northern slope did not have significant difference (p