Journal of Water and Soil Science
Year:2018 | Volume:22 | Issue:2|Papers Count:30

Soil erosion by surface runoff introduced as surface erosion is one of the main mechanisms of land degradation in the hill slopes. Slope characteristics including aspect and gradient can control the differences of soil properties along the hillslope. This study was conducted to investigate the effect of slope aspect and gradient on variations of some soil properties in the short slopes. Five hills including both north and south aspects with different gradients (9-10%, 13-16%, 17-22%, 29-31% and 33-37%) were considered in a semi-arid region with 30 ha in area, in the west of Zanjan, northwest of Iran. The hills were weakly covered with pasture vegetation covers. Soil samples were collected along the slopes from two depths (0-5 cm and 5-15 cm) in four positions with 2 m distance along each slope with two replications. A total of 160 soil samples were analyzed for particle size distribution (sand, silt and clay), gravel and bulk density. Surface erosion was determined based on the variation of grain size distribution and bulk density. Differences of the grain size distribution and surface erosion between the two slope aspects and among the slope gradients were analyzed using the Tukey test. No significant difference was found between slope aspects in surface soil erosion. Nevertheless, surface soil erosion was affected by slope gradient in each slope aspect (R2= 0. 78, p< 0. 05). Surface erosion in the north slopes was more dependent on the slope gradient, as compared to the corresponding south slopes. In the south slopes, surface erosion was affected by the movement of silt particles from soil surface, while in the north slopes, it was significantly affected by the loss of clay particles.

In order to study the effects of different irrigation regimes and different levels of salinity on the growth parameters of Quinoa (Chenopodium quinoa Willd. ), this experiment was performed in the research green house of Water Engineering Department, at f Gorgan University of Agricultural Sciences and Natural Resources, during 2016. The experimental design was a factorial with n a randomized complete design in three replications. Treatments included three irrigation levels (100, 75 and 50 percent of water requirements calculated by the evaporation pan class A) and five salinity levels (0. 5, 4. 3, 8, 11. 8, 16 dSm-1). The results showed that the effect of irrigation on the Leaf area index, chlorophylls and RWC (P<0. 01) and Leaf length, and width (P<0. 05) was significant. The effect of salinity levels on the Leaf area index, chlorophylls, Leaf length and width, RWC, Specific leaf weight (P<0. 01) and Leaf petiole length (P<0. 05) was significant too. The interaction between irrigation and salinity levels on chlorophylls and RWC (P<0. 01) and Leaf width (P<0. 05) was significant as well. According to the results, Quinoa had a good tolerance to the elevated levels of deficit irrigation. Decreasing the irrigation levels from 100 to 50 percent of pan evaporation resulted in the reduction of the Leaf area index and RWC to 24. 6 and 7. 3 percent, respectively. The result also showed that Quinoa had a good tolerance to the elevated levels of salinity, the mixing sea water, and tap water at rate of 30 percent, with control treatment having no significance for all of the parameters. It seems that good stand establishment in the saline soils and water conditions could be insured if proper management is applied in the farms.

In order to investigate the flow formation on dunes, the experimental data from a flume 12 meters long, located in Hydraulic Lab at Technical University of Graz (Austria), were collected. In this study, dunes (particle sizes of 13 and 6 mm) in a 2-D plan were developed with the wavelength of 1 meter, the lee angle of 8 degree, and the crest heights of 4 and 6 cm; these were uniformly installed across the width of flume. The analysis of the experimental flow velocity profiles measured by ADV and PIV technology and the numerical profiles modeled by SSIMM showed that in the same hydraulic conditions, there was no significant relation between drag coefficients of particles on dunes and flow discharge variation, while the water depth reduction caused a sudden increase in the drag coefficient up to 66%. Also, reducing particle size of the dune increased the drag coefficient and there was a significant relation between particle size (diameter) and dune formation, so that in smooth crested conditions, as compared with the sharp crested dune, the drag coefficient was increased up to 32%.

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.

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.

Due to the lack of necessary equipment for measuring and recording changes in watershed runoff and flood situation after the implementation of corrective actions, using hydrologic models is considered as an efficient tool to assess the undertaken actions and simulate the behavior of the watershed before and after the implementation of these measures. The present study aimed to simulate the effects of corrective actions on runoff components using HEC-HMS hydrological models in the form of a rangeland and watershed plan in 2006 and the predicting plan of applicable operations in a region in the Meikhoran watershed, Kermanshah. For this purpose, three scenarios including the conditions before running the rangeland and watershed plan, the conditions after running the project and requirements and enforcement actions resulting from the proposed location map were considered in the spring of 2006. First, a map of the curve number (CN) changes was prepared under all three scenarios caused by the vegetation changes and by implementing HEC-HMS model, the curve number criteria, the peak discharge and flood volume were determined to assess the changes in hydrological basins and their values for all three scenarios were calculated and compared. The results showed that the HEC-HMS model for the base period (first scenario) with Nash-Sutcliffe coefficient 0/551 and the coefficient of determination 0/63 had an acceptable accuracy in predicting runoff. Nash-Sutcliffe coefficient for the second and third scenarios was 766/0 and 0/777, respectively. Also, the results showed that in the second scenario, there was an 8/85 and 7/74% decrease in the peak flows and runoff volumes, respectively, and these values for the proposed operation were estimated to be 12. 84% and 6. 33%, respectively. Overall, the results indicated the considerable impact of rangelands and watershed management (third scenario) on the reduction of effective runoff components, particularly flood peak, on the basis of the location model.

Salinity adversely affects crops metabolism and yield. The present work was conducted to evaluate the singular and interaction influences of Arbuscular mycorrhizal (AM) fungi and brassinolide, as an active group of (brassinosteroids) BRs, on some physiological parameters of wheat plants to cope with salt stress14-day old mycorrhizal (Glomus mosseae) and non-mycorrhizal wheat (Triticum aestivum L. ). Plants were foliar sprayed with 0 and 5 μ M epibrassinolide 3 times once every two days. Then, each group was treated with 0 and 150 mM NaCl once every 3 days for 10 days. After salt treatment, some plants were harvested to estimate the leaf reducing sugar and glycine betaine contents. After the final growth, all wheat plants were harvested to measure some yield parameters. Synergistic influence of brassinolide and AM fungi was observed in protein and 1000-grain weight. It seemed that this was rooted in the increased accumulation of reducing sugars and glycine betaine, both helping to maintain osmotic potential in cells under high salinity in soil.

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.

In this study, the distribution of heavy metals pollution including arsenic, antimony, nickel, copper, cadmium, cobalt, bismuth, lead and zinc in the stream sediments of Zarshuran-Aghdarreh area was investigated by using statistical techniques and the geometric integration of each sample basin. For this purpose, the degree of pollution in 154 stream sediment samples was analyzed and the distribution maps for enrichment factors were prepared by using a combination technique, pixel estimation, and statistical and geostatistical methods. The results of calculating the enrichment factors indicated that the higher enrichment was related to arsenic, antimony, bismuth, cadmium and lead. Furthermore, the concentration of zinc, copper, lead, arsenic, antimony, cadmium and bismuth in the stream sediment samples was higher than the global average. Application of the principal component analysis on the data led to the recognition of 9 main components for the dataset; the first 5 were components with eigen values greater than 1 and a cumulative percentage more than 85%. Arsenic, antimony, cadmium, lead and zinc in the first component, cobalt in the second component, bismuth in the third component, copper in the fourth component and nickel in the fifth component had the highest values.

In the recent decades, due to the development of the pressurized irrigation systems, the relationship between the water and energy has been extended more than ever. So, according to problems due to the water shortage, energy saving is considered as one of the most important challenges in the agriculture section. In this study, by considering the capabilities of the pumping systems, variable speed pumps have been examined in an agro-industrial region of Ashrafiyeh (Qazvin province, Iran) with an area of 85 ha. The energy consumption during the ten-year operation was analyzed in the five operation scenarios by the MATLAB/SIMULINK software. The results showed that the consumed electrical energy by using variable speed pumps was approximately decreased up to about 18 percent, as compared to the fixed speed pumps. The results of the evaluation of the consumed energy showed that the current operation circumstance increased energy losses up to about 60 percent, as compared to the other operation methods. The results also revealed that the overall energy efficiency for the current operation circumstance was 52 percent (78 percent of Nebraska Performance Criteria).

Bhalme & Mooley Drought index is one of common indices used in drought studies. Due to the fact that drought indices can have different sensitivities to different region conditions and the length of data recorded, 62 synoptic and climatological stations were selected within a homogonous region to study this index advantages and to assess the effect of climate, precipitation regime, and data record on the index. The best results were found for the humid climate. Also, this index had acceptable results for semi-mediterranean regimes regarding all different time scales,; however the situation was different for Mediterranean regimes, showing the best results for the time scales simultaneous with the precipitation period. From the data record point of view, the best results were estimated during the first 31-years of the common period which has correspondence with the results of the 36-year period.

The effect of broad-leaved forest trees (Alnus glotinusa, Ulmus glabra, Popolus caspica and Parrotia persica) and their canopy position on soil C and N storage and mineraization in the plain forest areas of Noor was investigated. Soil samples were taken from two positions (near and away from the main stem) with the microplots of 30×30×15 cm. Litter (C and N), soil physical (bulk density, texture and water content), chemical (pH, EC, organic C, total N and available Ca), biochemical and biological (N mineralization and microbial respiration) characteristics were measured at the laboratory. Carbon mineralization rate (CMR) was calculated using the equation [incubation time period (hour) ×soil volume (gr) / CO2 amount (mol C)]. Soil C and N storage (ton/ha) was calculated by C and N contents, bulk density, and the soil sampling depth. The results showed that there was no significant difference between the C storage under the studied tree spcies, whereas N storage presented significantly greater amounts, under Alnus glotinusa (0. 79 ton/ha) rather than Ulmus glabra, Popolus caspica and Parrotia persica (0. 69, 0. 45 and 0. 21 ton/ha, respectively). The higher values of soil C (0. 001 mol C/kg) and N (0. 3 ml N/kg) mineralization were significantly recorded under Alnus glotinusa instead of tree species. Soil C and N storage and mineralization process were not affected by the sampling positions. According to the results, soil C and N storage and mineralization were influenced by litter quality and soil chemistry.

The goal of this study was to evaluate tannic acid as a coagulant in turbidity removal. Tests were designed using Taguchi method and carried out on the synthetic and natural turbid samples. In order to optimize turbidity removal by tannic acid, seven factors including pH, coagulant dosage, rapid mixing rate, slow mixing rate, slow mixing time, sedimentation time and initial turbidity were investigated. The results revealed that in optimum conditions, tannic acid could n remove up to 71 percent of synthetic turbidity and 66 percent of natural turbidity; also, tannic acid showed more coagulation activity in the lower initial turbidities. ANOVA analysis showed that initial turbidity and slow mixing time were the most important parameters in the turbidity removal by tannic acid. In general, this study showed that tannic acid was capable of removing turbidity and could be used instead of common coagulants in the preliminary treatment.

Determination of the required water for crop and irrigation programing is of major importance in the sustainable use of water resources. The national water document is the output of the ‘ net irrigation required for crops’ , which is presented for the optimum allocation of water resources for the demands. The Penman-Monteith-FAO method is used in the calculation. Updating the national water document is necessary to overcome its some limitations, and to provide more adaptation to the plains conditions of the country. The objective of this study was the recognition of the existing problems of the water national document and appropriate method development for implementing in the country plains. In this regard, the required water of different crop patterns was calculated using the Penman-Monteith-FAO method in the Ghazvin plain (as a dry plain), Ghazvin province, and Fomanat plain (as a wet plain), in Fomanat province, in the period of 1976-2005. The results were compared to the water national document. It was shown that annual potential evatranspiration varied between 1330 and 1587. 1 mm in the Ghazvin plain, and between 743 and 809 mm in the Fomanat plain. The calculated evapotranspiration in the present study was about 40. 6% more than water national document in the Takestan station, in Ghazvin plain, as a sample station.

The grape leafhopper, Arboridia kermanshah Dlabola (Hemiptera, Cicadellidae), is an economically important pest of most vineyards in Isfahan. The effects of two irrigation regimes [normal (100 liter/ tree/ week) and minimum (100 liter/ tree/two weeks)] seasonal population changes and the damage of A. Kermanshah as well as the percentage of leafhopper egg parasitism by Anagrus atomus were studied on five grape cultivars including Shahani, White Rishbaba, Askari, Black Rishbaba and White Yaghoti; this was done in a completely randomized blockdesign with split plots in three replications at Isfahan University of Technology in the 2005-2006 period. Adults and nymphs were assessed by weekly sampling using a vacuum insect collector (D-VAC). Non-parasitized and parasitized eggs were counted weekly by clipping three leaves from different strata of vine canopy as a sample unit, in each plot. The results showed that the leafhopper population density, damage percentage and egg parasitism in both years of study in the normal irrigation plots were higher than those with the minimum irrigation. The maximum density of adults and nymphs was observed in June and early July on the White Yaghoti. The highest egg density and parasitism were recorded in June and October-November, respectively, on black Rish-baba in the normal irrigation. The highest damage was on the white Yaghoti in August and September, and the lowest damage was on Askari and Shahani, both in the normal irrigation regime.

Evaluation of the ecological sustainability of different cropping systems is crucial to achieve sustainable agriculture. This evaluation is accessible via soil quality assessment. Therefore, to study the mid-term effects of different conservation tillage systems (no tillage and minimum tillage) and cover cropping on the biological indicators of soil quality, a factorial experiment in a completely randomized block design was conducted in Dastjerd region (Hamedan). Three levels of tillage (NT: no tillage, MT: minimum tillage and CT: conventional tillage) and two levels of cover cropping (C1: Lathyrus sativus and C2: no cover crop) were applied for four consecutive years. Soil sampling was performed in the fourth year of experiment in two steps (1-before cover crop plantation, and 2-after harvesting main crop) with three replications. Most indices (total organic carbon, active carbon, basal respiration, phosphatase activity) were significantly affected by cover crop, tillage systems and sampling time, as the highest values were obtained in NT-C1 in time 2 and the lowest ones in CT-C2 in time 1. For instance, after four years application of treatments, the mean active carbon content was increased from 927 mg/kg in the conventional tillage + no cover crop to 1350 mg/kg in the conservation tillage systems + cover crop. Therefore, conservation tillage practices combined with Lathyrus sativus cover crop were shown to be the most appropriate management for soil quality maintenance and improvement.

Due to the water scarcity in Iran, it is important to provide strategies to reduce water consumption in the agriculture sector. Zycosil is a nanotechnology material that makes a great hydrophobe in the soil. This study was conducted based on completely randomized block design within microlysimeter with the height of 15 cm and the diameter of 8 cm to investigate the hydrophobic effect on the amount of consumed water in pepper. Sweet pepper seedlings were planted in them; then the treatments were applied. The Z25, Z50 and Z75 treatments consisted of covering 25, 50 and 75 % of the soil surface by Zycosil; these were compared with the control (Ctrl-no Zycosil application) in three replications. The results showed that Z75 treatment reduced 27% water consumption and increased the fresh yield by approximately 62 %. The increased yield of Z25 and Z50 was 5 and 26 %, respectively. Dry pepper yield was increased in Z25, Z50 and Z75 treatments by 22, 19 and 80%, respectively, as compared to Ctrl treatment. The amount of water consumed was decreased by 10 % per 25% coverage level. The least amount of water use efficiency was observed in the control treatment (1. 28 gr/cm3). The Z75 had the highest water use efficiency (2. 96 gr/cm3). Hence, the application of hydrophobic material such as Zycosil in the soil surface reduced water evaporation and increased water retention. This increased the yield and water use efficiency.

Spectral Reflectance of suspended sediment concentration (SSC) remotely sensed by satellite images is an alternative and economically efficient method to measure SSC in inland waters such as rivers and lakes, coastal waters, and oceans. This paper retrieved SSC from satellite remote sensing imagery using radial basis function networks (RBF). In-situ measurement of SSC, water flow data, as well as MODIS band 1 and band ratio of band 2 to 1 were the inputs of the RBF. A multi-regression method was also used to make a relationship between the in-situ data and the water reflectance data retrieved from MODIS bands. The results showed that RBF had the best SSC prediction error (RMSE=0. 19), as compared to the multi-regression and sediment rating curve methods, with the RMSE of 0. 29 and 0. 21, respectively.

Nowadays, water resource management has been shifted from the construction of new water supply systems to the management and the optimal utilization of the existing ones. In this study, the reservoir operating rules of Doroodzan dam reservoir, located in Fars province, were determined using different methods and the most efficient model was selected. For this purpose, a monthly nonlinear multi-objective optimization model was designed using the monthly data of a fifteen-year period (2002-2017). Objective functions were considered as minimizing water scarcity index in municipal, industrial, environmental and agricultural sectors. In order to determine the operating rule curves of reservoir, in addition to the nonlinear multi-objective optimization model, the methods of ordinary least-squares regression (OLS), fuzzy inference system and adaptive network fuzzy inference system (ANFIS) were used. Also, the reliability, resiliency, vulnerability and sustainability criteria were used to compare the different methods of reservoir performance rules. The results showed that ANFIS model had the higher sustainability criterion (0. 26) due to its greater reliability (0. 7) and resilience (0. 42), as well as its lower vulnerability (0. 13), thereby showing the best performance. Therefore, ANFIS model could be effectively used for the creation of Doroodzan reservoir operation rules.

To design cost-effective and efficient drip irrigation systems, it is necessary to know the vertical and horizontal advance of the wetting front under the point source; also, the proper management of drip irrigation systems requires an awareness of the soil water distribution. Many factors influence wetting pattern dimensions, including discharge, land slope, irrigation time and soil texture. The purpose of this study was to investigate the applicability of the support vector machine in simulating the wetting pattern under trickle irrigation. After preparing a physical model made of Plexiglas with specific dimensions and filled with silty clay loam soils, experiments were conducted in the irrigation laboratory of Razi University, Iran, with emitters of 2, 4, 6 and 8 l/hour discharge during the irrigation intervals of 2 hours and 24 hours redistribution and 0, 5, 15 and 20% slope with three replications. In this study, the statistical indicators R2, RMSE, MBE and MEF were used. R2 values for the wet depth, width and area were 0. 96, 0. 96 and 0. 92, respectively. Regarding the MBE value, the SVM model estimated the wet width and depth parameters to be 3% less than the actual value, and simulated the wet area 2. 04% less than the real value. Also, according to the MEF and RMSE values, the SVM model simulated the wet area parameter with more error. Overall, the results showed that the SVM model had a high ability to estimate the wetting pattern parameters.

In order to optimize the irrigation system performance, it is essential to get information about water balance components in the farm. So, the objective of this study was evaluating the performance of the WFD device in determining water penetrated fate in the soil at each irrigation occurrence as one of the important components in evaluating the irrigation water efficiency. By having the water amount infiltrated in the root zone and the deep percolation amount collected and determined by WFD device, contribution of surface losses related to every irrigation occurrence can be determined by the employing water balance equation. This research was carried out in the form of completely randomized design blocks in three replications and under the treatments of 60, 80, 100 and 120% of the irrigation requirement supply of a potato plant in the research farm of Shahr-e Kord University in 2014. To gather the growing season data, before the planting operation, various WFD devices were installed at different depths and locations along furrow. In addition to WFD data, input discharge (using counter), output discharge (measured by flume type 1) and values of soil moisture (theta-probe device) were collected during the harvesting season. The results showed that the mean Nash– Satcliffe coefficient of comparison between the values of calculated and measured surface losses corresponding to it, and also comparison of the values of the calculated and measured residual moisture before each irrigation occurrence were obtained to be 0. 87 and 0. 98, respectively. Quantity of this indicator in the two conducted comparisons represented the correct and exact performance of the WFD device in the farm operation evaluation. During the farm evaluation process under the experimental furrow, distribution uniformity averages in the experimental treatments were acquired to be 75. 56, 83. 78, 88. 06, and 90. 34%, respectively. Likewise, water amount average percolation of root zone (depth losses) in experimental treatments at each irrigation occurrence was measured to be 0. 02, 0. 07, 0. 27 and 0. 47m3 for each furrow.

Trees crown can be regarded as main factor contributing to the conservation and support of soil in many ecosystems including semiarid forests in Zagross. The aim of this study was to find out the effect of tree crown of pictachio (Pistacia atlantica Desf) on N, OC, P, pH, EC and the texture of the soil. Soil samples were collected in and outside the crown of 5 single pistachio trees on four directions of each tree in a northern slope from the 0-5 cm depth of soil in the Sarvabad region, Kurdistan. The results of this study showed that the amount of the soil organic carbon was decreased from 6. 71% in the soil inside tree crowns to 4. 73% in the soils outside the tree canopies. The soil inside trees had a higher concentration of soil nitrogen (0. 406%) than the one outside (0. 224%) the tree crown; the concentration of phosphorus was measured to be 32. 7 mg/kg in the soil inside canopy, while it was 21. 1 mg/kg in the soil of outside the tree canopy. EC under the tree crowns was more than that outside the canopy. The results, therefore, showed that soil texture was lighter inside the canopy, as compared to outside; however, the acidity of the soil was not affected by tree crowns and no significant differences were observed in different areas of the crown. Therefore, Persian turpentine trees have positive impacts on the soil properties in Zagros forests and eliminating them will lead to the significant loss of soil fertility and greater soil erosion.

One of the main sources of runoff in arid and semi-arid mountainous highlands is typically composed of before Quaternary formations. Since the structure and lithology of formations are different, varying formations can have different significance in terms of runoff and sediment. The present study aimed to investigate the sediment production potential and the runoff generation threshold on three formations (Shirkooh Granite, Shale, Sandstone and Conglomerate of Sangestan and Taft Limestone) in Shirkooh mountain slopes. The 60 mm/h rainfall intensity with the 40 minute continuity, according to region rainfall records, and the ability of the rainfall simulator were selected as the basis for the study. Field experiments were conducted in dry conditions based on one square meter plot on rocky slopes with a gradient of 20 to 22 percent and a maximum thickness of 30 cm of soil. The results showed that in 60 mm/h rainfall intensity, the minimum rainfall to produce runoff on Sangestan, Shirkooh and, Taft, was 10, 10. 7 and 16. 7 mm, respectively. The maximum amount of the sediment was measured on Sangestan, Taft and Shirkooh, respectively. Statistical tests related to runoff and sediment production on all three formations confirmed a significant difference at the 5 % level. In terms of the time required to start runoff, the minimum time was for Sangestan, Shirkooh and Taft, respectively. According to the results, in terms of the potential for runoff generation and sediment production, Sangestan, Shirkooh and Taft can be ranked from high to low levels.

Since the introduction of cities and urbanization, healthy water supplement and urban wastewater treatment have been considered as an important factor to evaluate progress in the urban areas. Tehran as a megacity is facing the lack of water. Tehran water supplement is far from its area; therefore, Tehran-Karaj plain has been considered in this study. So, Tehran water quantity index using the DPSIR model (Driving force, Pressure, Status, Impact and Response) in a period of 3 years (2008-2010) was considered in this paper. Driving forces included population, urbanization, green spaces, and industries. Pressures on urban water included water consumption, water losses, rainfall and evaporation. Then, Tehran water quantity status was investigated based on the existing water in dam reservoirs and groundwater resources. Their impacts on urban area were evaluated and finally, appropriate responses were presented. Some of the presented approaches included industries transmission, improvement of water consumption pattern, improvement of the water treatment plants status and unconventional water resources reuse, identification and rearrangement of subterranean, improvement of irrigation systems operation, and reduction of Tehran urban population.

Emitter clogging for using agricultural wastewater increases the operating costs and reduces the motivation of farmers. The new method to reduce the emitters clogging is the use of a Merus ring that does not have the problems of chlorination and pickling methods, such as pollution and high cost. Due to the importance of agricultural wastewater use, this study investigated the emitters clogging and the effect of Merus ring on the emitter's efficiency in a trickle irrigation system. The treatments including irrigation water (well water and wastewater) and modified water (irrigation with Merus ring and irrigation without Merus ring), as the main factor and the emitters type treatment including Irritec (D1), Corona (D2), Axios (D3), Netafim (D4), Polirood (D5), and Paya (D6) as the sub treatments were performed in three replications. The results showed that the agricultural wastewater caused the emitters clogging in irrigation water and modified water treatments, but over time, the Merus ring had a positive effect on the evaluation parameters of the emitters. For agricultural wastewater, in the first and last irrigation periods, the average discharge of emitters with the Merus ring was 0. 05 and 0. 33 Liter per hours, respectively, more than the treatment without the Merus ring. The uniformity coefficient of emitters in the first and last irrigation periods, in well water with the Merus ring, was 0. 31%and 6. 67%, respectively, more than that in the well water without the Merus ring. Also, the uniformity coefficient of emitters in the first and last irrigation periods in agricultural wastewater with the Merus ring was 0. 85% and 12. 10%, respectively, more than that in agricultural wastewater without the Merus ring. At the end of irrigation period, the results showed that Netafim and Axios had the best and weakest efficiency, respectively. In general, the emitters used in the treatment of well water with the Merus ring had the highest discharge and the emitters used in the treatment of wastewater without the Merus ring had the lowest discharge.

In recent years, microbial contamination of surface and groundwater is a serious problem in some countries, leading to dangerous diseases. Soil salinity and irrigation water can affect the amount of transport or survival of bacteria in soil. In this study, the effect of different levels of salinity of irrigation water with EC: 0. 5, 2. 5, 6 ds/m and three manures including poultry manure, cow manure and the mixture of poultry and cow manure with 10 ton ha-1 on the transport of Escherchia coli was investigated in disturbed soil columns with 30cm height and 10cm diameter under unsteady-state water conditions. The concentration of Escherchia coli was measured. The severity of the effluent contamination of the treated columns with water salinity was 6 ds/m, which was less than that with the salinity of 2. 5 and 0. 5 ds/m. This difference was significant at the 0. 01 probability level. Also, the effluent contamination of poultry manure-treated columns was greater than the cow manure and the mixed manure, and the contamination of mixed manure was greater than that of cow manure. The interaction of different salinity treatments on the concentration of Escherchia coli in different fertilizer treatments was significant at the 0. 01 probability level. The results showed that the concentration of the released bacteria was affected by irrigation water salinity and with increasing the salinity, the concentration of the bacteria was reduced.

In the present paper, fluctuations of inflow into the Karun-4 Dam under different scenarios of the climate change for the future period of 2021-2050 were investigated. For this purpose, the outputs of the HadCM3 model under the scenarios of B1 (optimistic) and A2 (pessimistic) were utilized for the fourth report; additionally, the outputs of the ensemble model under RCP 2. 6 (optimistic) and RCP 8. 5 (pessimistic) scenarios were used for the fifth report. Moreover, in order to estimate runoff in the future period, the artificial neural network was considered as a rainfall-runoff model. The results indicated that the average annual precipitation in the five study stations under B1 and RCP 2. 6 scenarios was increased by 15 and 5%, respectively, while it showed a decrease equal to 8 and 6%, respectively under the scenarios A2 and RCP 8. 5. Furthermore, the average annual temperature in all scenarios showed increase, which was at least 1. 06 ⁰ C under the scenario B1 and 1. 89 ⁰ C under scenario RCP 8. 5. Examining the input inflow into the Karun-4 dam showed that under both B1 and RCP 2. 6 scenarios, the annual inflow will be increased by 1. 8 and 1. 5%, respectively; under the two scenarios A2 and RCP of 8. 5, the annual inflow will be decreased to 10. 4 and 9. 8%, respectively.

This study covers a large agricultural and industrial area of Isfahan province, including three types of land use, i. e., agricultural, uncultivated, industrial and urban types. A total of 275 samples from surface soil (0-20 cm) were collected and water soluble fluoride concentrations of them were measured. The spatial structure of water soluble fluoride in the soils was determined by omnidirectional variogram in the GS+ software. The spatial distribution of water soluble fluoride in the soil was mapped by employing the point kriging method in the SURFER software. The results showed that the mean of the water soluble fluoride concentration in Isfahan soils (0. 85 mg L-1) was higher than the mean world soils (0. 53 mg L-1). The water soluble fluoride showed moderate spatial dependence, indicating that the spatial variability of water soluble fluoride was mainly controlled by intrinsic and extrinsic factors. The mean water soluble fluoride concentration was significantly higher in agricultural and urban areas, as compared with the uncultivated land. This could be due to application of phosphate fertilizer in agricultural areas and the atmospheric fallout of fluoride from the industrial sources such as steel factories. According to the generated kriging map, the higher concentration of fluoride was mainly recorded around the Zayande Rood River and in the central and western parts of the study area.

This study was conducted based on a randomized complete block design and a factorial experiment with three replications in regions to investigate the effect of different rates and times of nitrogen on the quantitative properties of safflower. The first factor was different nitrogen rates including 0, 60, 120 and 180 kg ha-1, and the second one was nitrogen application time including seed sowing, rosette and the before flowering stage; these were 1-0-0, 1/3-2/3-0, 2/3-1/3-0 and 1/3-1/3-1/3 with the Goldasht variety. The results showed that nitrogen rate had a significant effect on all studied traits. Nitrogen application time also had a significant effect on capitulum number and yield at p>0. 99 and on the length of plant, nitrogen adsorption, agronomic efficiency and apparent recovery at p>0. 95. So based on the results, the recommended consumption of 60 kg/ha N was split into three equal amounts at the time of planting, rosette and flowering or 1/3-2/3-0, in Kerman area.