Showing 64 results for لک
H. Rahmani, A. Lakzian, A. R. Karimi Karouyeh, A. Halajnia,
Volume 17, Issue 65 (fall 2013)
Abstract
Urease is one of the most important enzymes in nitrogen cycle. The clay particles (with high surface area) play an important role in the stability of these protein compounds (enzymes) against various environmental factors. In order to examine the interactions between urease with sepiolite and vermiculite, three in vitro experiments were conducted separately in a completely randomized design. Two experiments were carried out with two replications. Treatments included six incubation times (0, 1, 2, 5, 10 and 20 days) and five levels of temperature (10, 20, 30, 40 and 50 ˚C). The third experiment was carried out in a factorial arrangement with two replications. Factors included three levels of pH (5, 7 and 9), and six-levels of enzyme concentrations (0.05, 0.25, 1, 5, 15 and 30 units). The results showed that the activity of adsorbed enzyme was more than free enzyme during the incubation time. The optimum temperatures for activity of free and adsorbed enzymes were 30 and 50 ˚C, respectively. It was concluded that enzyme adsorption on clay surfaces increases enzyme stability against environmental changes. Also, the results showed that the highest levels of urease adsorption on sepiolite and vermiculite occurred at pH 9 and 7, respectively. Adsorption isotherms of Enzyme showed that Vermiculite adsorbed urease with higher affinity compared to Sepiolite.
R. Malekian, J. Abedi-Koupai, S. S. Eslamian,
Volume 18, Issue 68 (summer 2014)
Abstract
In this study, the effect of clinoptilolite zeolite, as a soil amendment, on the parameters related to water and nitrogen movement in soil was investigated. Parameter and uncertainty estimation in the unamended (control) and amended soil
(Z), was performed using the sequential uncertainty fitting algorithm (SUFI-2) which is linked to LEACHN (in the LEACHN-CUP software). The goodness of prediction uncertainty was judged on the basis of P-factor and R-factor. P factor, R-factor, and Nash-Sutcliffe coefficient (NS) was obtained 0.71, 0.76, and 0.92, respectively, in the prediction of the accumulated drainage from control. The results in prediction of the accumulated drainage from Z treatment using hydraulic parameters obtained in control were satisfactory (P-factor = 0.87, R-factor = 0.78, and NS = 0.87). P-factor, R factor, and NS were 0.87, 1.36, and 0.91, respectively, in the prediction of NO3-N leaching at control. According to the P-factor and R-factor values (P-factor = 1, R-factor = 2.46), application of the control parameter ranges in the prediction of NO3-N leaching at Z treatment produced a large uncertainty. By adjusting the parameters in control for zeolite amended soil, the estimated values for denitrification rate, distribution coefficient, and soil/solution NO3-N nitrification rate were greater in zeolite-amended soil compared to control.
H. Karimi, A. Fotovat, A. Lakzian, Gh. H. Haghnia, M. Shirani,
Volume 18, Issue 68 (summer 2014)
Abstract
In recent years, due to the increased population, urbanization and changes in human consumption patterns, urban, industrial and agricultural soils have been exposed to various pollutants such as heavy metals. The objective of this research was to identify hotspots of Pb by using global and local Moran Indices in urban and suburban soils of Kashafrood catchment. A total of 261 surface soil samples (0-15 cm deep) were taken using irregular girding network method and their total Pb concentrations were measured. The positive Moran index at confidence level of more than 99 percent showed the spatial clusters between observations. On the basis of local Moran index results, 15 samples were introduced as hotspots (high-high value) located southeast of Mashhad plain. Exclusion of extreme values resulted in the addition of high-high cluster (hotspots) leading to the extension of these areas to the West of the Mashhad city.
These areas are introduced as hotspots due to the urban land use, the direction of prevailing wind, and the area being close to Mashhad airport.
A. Malekian, H. Alipour, M. Kheirkhah Zarkesh, S. Gharachelo,
Volume 18, Issue 69 (fall 2014)
Abstract
Determine appropriate locations with accuracy and speed required is for Floodwater spreading very important. The main objective of this research, preparation, use and evaluation decision support systems is based on GIS and RS techniques to identify and prioritization appropriate areas Floodwater spreading in the study area. In this study area suitable for flood water spreading were selected based on major criteria four, sub criteria eight and index twentyfour. Finally five scenario will be provide and assessment (a scenario based on the relative values for the criteria four, and different scenarios four based on the obvious one of the main criteria). Comparison desirability average among the scenarios five indicate that it is Sub watershed (1) In the scenario third (infilteration preferred, water application preference and equality of all the main criteria) had a higher average desirability therefore between Sub watershed 2 in this scenario is preferred more than the other Sub. Of between the two sub watershed ivar region considering that the desirability average, sub watershed (1) and implemented of between scenarios, scenario (1) (infilteration major criteria preferred) were selected as first priority. Second priority for Floodwater spreading site selection is belong to sub watershed 2, and with scenario (1).
M. S. Maleki, H. Byatt, T. Ebadi,
Volume 19, Issue 71 (spring 2015)
Abstract
Some recent research has indicated that certain alkaline contaminations may adversely affect mechanical properties of clayey soils. To examine the potential impact of alkaline divalent barium on the swelling characteristics of KAHRIZAK clay, the major solid-waste landfill at south of Tehran, a systematic set of experiments was conducted. Observations indicated that the swelling in the studied soil that belonged to the CH-MH group with a PI of 28.44, was reduced by about 17, 37, 48 and 54 percent, and swelling pressure by about 41, 55, 65 and 67 percent, respectively, after addition of barium chloride solutions to concentrations of 0.25, 0.5, 0.75 and 1.25 molal. It was also found that addition of barium chloride solutions to concentrations of higher than 1 molal had a little effect on reduction of swelling and swelling pressure.
A. Jafarishalkoohy, M. Vafaeian, M. A. Rowshanzamir, M. Mirmohammadsadeghi3,
Volume 19, Issue 73 (fall 2015)
Abstract
A laboratory research program was arranged to study the effect of different factors influencing the stability of fine soils against wind action. For this purpose, a laboratory wind tunnel was stabilized and several soil samples were examined by putting the sample trays inside the wind tunnel for different rates of wind velocities. The tray for soil samples was 20´30 cm2 with the depth of 5 cm, and the fine soil samples were chosen with different sizes of particle and porosity. Because the main aim of this research was to investigate the effect of some polymer additives to the soil, many samples were made of the soils improved by different additives in different percentages. Furthermore, the effect of infiltration of the liquid additives was also examined, which could show different infiltration heights as functions of soil type, additive type and the height of pouring. Some of the results were examined by using software. The lab results in this research were compared with some proposed theoretical ones. It was found that as the average diameter of particles increases, erodibility under the same wind velocity decreases, and the applied polymer emulsions decrease the erodibility up to 90% compared to the initial condition. Impacts of dust emission due to the suspended dispersion of fine particles and creeping movements of coarse particles are mitigated as a result of treatment with these emulsions. Variations in erosion of soils at various wind velocities depend on the value of threshold friction velocity with the result that the soil erosion values in case of coarser soils after the increase in velocity would be higher than those of threshold friction velocity. Finally, a relationship is proposed for estimation of soil erosion in terms of wind velocity. The results are consistent with the transport rate relationships proposed by different scholars.
A. Sheikhzeinoddin, A. K. Esmaeili1 , M. Noshadi,
Volume 19, Issue 74 (Winter 2016)
Abstract
Chemical fertilizers have important role in modern agriculture, and in the other hand led to rigid environmental pollution. Urea fertilizer is one of the most widely used and least expensive nitrogen fertilizers in Iran. Since it is high solubility in water a significant of it, if irrigation or precipitation is heavy, easily washed and led to change to change the quality of groundwater, rivers or seas. Hence, in this study the effects of deficit irrigation and fertilization on pollution using SWAT for Tashk-Bakhtegan basin (land area between Dorudzan dam and Khan Bridge) were simulated. This model by comparing model outputs with actual observations of hydrological, crop yield (wheat, barely, corn and rice) and nitrate by using SUFI2 algorithm in SWAT_CUP software were calibrated and validated. Then the calibrated model used to evaluate different management strategies (e.g. irrigation and fertilizer amount). When the impacts of different levels of urea (0 to 70 percent reduction in urea application) were modeled, yield of these crops reduced between 1 to 27, 0.8 to 24, 0.42 to 21 and 0.47 to 9 percent for wheat, barely, corn and rice, respectively. However, these tends to decline nitrate leaching 16-81, 18-80, 15-85 and 12.5 to 83.6 percent, respectively for these crops. Therefore, by comparing yield and nitrogen loss changes, this result can conclude that a significant reduction in nitrogen loss by minimum cost on yield can achieved by optimize fertilizer application.
Z. Feyzi, A.r. Keshtkar, A. Malekian, H. Ghasemieh,
Volume 20, Issue 76 (Summer 2016)
Abstract
Shortage of rainfall and also relatively high intensity precipitations in short-term are characteristics of arid regions of the world, such as central of Iran. Studies have indicated that massive flooding causes great loss of life and properties every year. Also, Water scarcity in arid and semiarid regions of the world will cause fragile living conditions in these areas. Therefore, it is needed to reduce runoff rates using actions such as dam construction or artificial recharge techniques. In this study, seven factors were applied such as the slope, surface permeability, transmissibility in alluvium, alluvial quality, land use, runoff volume and thickness of the unsaturated layer to determine suitable areas and site selection for flood spreading and artificial recharge in south of Kashan plain. After preparing the digital layers, criteria weights were determined using Fuzzy AHP. The weighted maps were acquired and merged together. Results indicated that land use criterion with the greatest weight (0.22) was determined as the first priority in the site selection for flood speading. The parameters of runoff volume, permeability, slope, depth of the unsaturated layer, alluvial quality, and transfer coefficient were accounted as the second to seventh priorities.
M. Ayoubi, R. Sokouti, M. J. Malakouti,
Volume 20, Issue 76 (Summer 2016)
Abstract
This study is aimed to investigate the spatial variation of soil macronutrients such as phosphorus, potassium and organic matter using different methods of Geostatistics and Geostatistical method combined with Fuzzy logic to estimate the values of this element to provide a spatial distribution map for the proper distribution of fertilizer in the plain of Uremia. Spatial variations in soil nutrients are natural but knowing these changes for careful planning and management particularly in the agricultural lands is simply inevitable. This information is necessary to increase the profitability and sustainable agricultural management. Therefore, to estimate the changes in the elements of places not sampled, the Kriging, Fuzzy Kriging, Cokriging and Inverse Distance Weighting methods have been used in GS +. In this study, Matlab 9.1 software was used to fuzzification of the data and GIS was used for the final mapping. The parameters MAE, MBE and RMSE were used to compare these methods. The results showed that the combined method of Fuzzy Geostatistic with the mean absolute error values for the elements phosphorus, potassium and organic matter i.e. 0.17, 0.18 and 0.18, respectively, is recognized as the preferred method based on which zoning maps have been prepared for P, K and OC in GIS.
H. Rahmani, A. Lakzian, A. R. Karimi, A. Halajnia,
Volume 20, Issue 78 (Winter 2017)
Abstract
Urea is one of the most commonly used nitrogen fertilizers in agricultural lands. The fate of this fertilizer in soils is greatly related to the soil urease enzyme activity, while this enzyme commonly exists in the adsorbed state on the surface of soil colloids, and especially clay minerals. In order to examine the kinetic properties of free and adsorbed Urease on the surface of sepiolite and vermiculite, an experiment was carried out with eight levels of urea concentration (5, 10, 20, 40, 60, 80, 100 and 120 mM). This experiment was done with enzyme concentration of 1 unit in temperature of 25˚C and pH=7. Adsorption of urease on the clay surfaces affected its kinetic properties compared to the free state. The results showed that urease enzyme obeyed Michaelis-Menten kinetic in both free and adsorbed states on the clay surfaces. Except free urease, the highest and lowest values of Vmax and Km were observed in urease-sepiolite and urease-vermiculite complexes, respectively. Also, the results showed that except free urease, the highest levels of Catalytic Efficiency were related to urease in the presence of vermiculite and sepiolite, respectively. The Effectiveness Factor was more for adsorbed urease on the sepiolite surface than adsorbed urease on the vermiculite surface, and the fact somehow suggests more complete diffusion in the presence of sepiolite.
M. Nadi, A. Golchin, E. Sedaghati, S. Shafie, S. J. Hosseini Fard, G. Füleky,
Volume 21, Issue 1 (Spring 2017)
Abstract
Soil organic matter is the largest source of organic carbon in the soil surface which played an enormous role in restoring balance, environmental sustainability, soil elements and climatic conditions. Organic materials influence physical, chemical and biological properties of soil and thus soil fertility directly and indirectly. The amount, type and composition of organic matter are different in different soil and climatic conditions. Different soil components can hold different combination of soil organic matter. In this study soil samples were collected from virgin, Populus and Alnus forests from Guilan Province, Iran. The amount of organic matter in the original samples and sand, silt and clay fractions were measured and the quality of organic carbon (13C) and hydrogen (1H) were determined in fractions by Nuclear Magnetic Resonance. Based on the results the amount of organic carbon in the original samples of Alnus forest was highest. among fractions, clay had the highest amount of organic carbon. The result of Nuclear Magnetic Resonance showed presence of different aliphatic and aromatic carbons and hydrogen in different samples. Virgin forest had the highest proportion of alkyl to oxygenated alkyl carbon ratio and Alnus forest showed the highest ratio of aliphatic to aromatic carbon,. Both mentioned ratios was higher in clay fraction than other two fractions.
M. Hayatzadeh, M. R. Ekhtesasi, H. Malekinezhad, A. Fathzadeh, H. R. Azimzadeh,
Volume 21, Issue 1 (Spring 2017)
Abstract
Soil erosion is undoubtedly one of the most important problems in natural areas of Iran and has destructive effects on different ecosystems. Considering that calculation of the sediment rate in sediment stations and direct measurements of erosion process is costly and difficult, it is critical to find ways to accurately estimate the amount of sediment yield in catchments especially in arid and hyper arid areas because of their high ecological sensitivity. One of the most commonly used methods in these areas is the sediment rating regression method. Therefore, in this study sediment observed data for 48 events (the corresponding discharge and sediment) in a 23-year period from Fkhrabad basin (Mehriz) were compared to the estimated data obtained from Multi-line rating method, extent middle class, middle class rating curve with correction factor QMLE, SMEARING correction coefficient FAO and Artificial Neural networks (ANNs). Finally, the accuracy of these methods were assessed using different evaluation criteria such as Root Mean Square Error (RMSE), coefficient of determination (R2) and the standard Nash (ME). Results showed that ANN outperformed the other methods with the RMSE, R2 and ME of 203.3, 0.86 and 0.66, respectively. The results suggest that these methods should be used cautiously in estimating the suspended sediment load in arid and hyper arid regions due to the nature of the observed data and temporal and seasonal flow systems in these regions. It was also indicated that the artificial neural network models have higher flexibility than other methods which makes them to be useful tools for modeling in poor data conditions.
S. Pishyar, H. Khosravi, A. Tavili, A. Malekian,
Volume 21, Issue 4 (Winter 2018)
Abstract
In this study, to study the status of water resources degradation in Kashan region, Isfahan Province, eight indices including: drop in groundwater, water salinity, irrigation efficiency, Well-to-Qanat development ratio, the pumping time, shortage of water supplies for animals and humans and the water negative balance were selected according to previous studies conducted on desertification in Iran and the world. Existing evaluation models were determined. Desertification map of the study area was provided according to MEDALUS model and selected indices. The selected indices were weighted using a multi-criteria decision method and each index having weight more than 0.5 were selected as the most effective indices of desertification. Again, the desertification status map of the study area was prepared by the most effective indices. Finally, the two desertification maps were compared. The results showed that the drop in groundwater, water salinity, the pumping time and water negative balance have the most effect on water resources degradation among selected indices. The results of comparing two groundwater degradation maps showed that based on map provided with eight indices, 87.78 and 8.30 percent of the total area are classified in critical conditions c and b, respectively. While the map provided by the most effective indicators shows that 99.15% of the total area is classified in the critical condition "c" and just 0.849% is classified in the critical condition "b". It can be concluded that to assess desertification status, it is better to first determine the indicators by weighting and prioritizing methods. This will identify the indicators that have not had a significant effect on the desertification phenomenon in the area and prevent their impact on desertification classes and reduction of scores.
J. Chezgi, H. Maleki Nezhad, M. R. Ekhtesasi, M. Nakhaei,
Volume 22, Issue 1 (Spring 2018)
Abstract
Underground dams are structures built in underground and are capable of saving and making the underground water available. In this research, by using the SWOT analysis model, suitable locations were investigated for the development of an underground dam in the Keriyan area of Hormozgan province. At first, the necessary data and information were provided by visiting the region and presenting a questionnaire to the residents of the area and experts to investigate the strengths, weaknesses, opportunities and threats in the region for the underground dams. In the final step, by using the SWOT model and QSPM matrix, a comprehensive and appropriate strategy for underground dams was determined. The results showed that among the internal factors, not decreasing the volume of the reservoir due to deposits and reducing the evaporation from the reservoir with a final value of 0.85 and 0.66, and among the external factors, the willingness and cooperation of the relevant organizations and the disruption of downstream water rights with a final value of 0.68 and 0.66 had the greatest impact on selecting the strategy. Based on the results related to the internal and external factors, the strategy was placed in the maximum-maximum quadrant; in line with the strategy, by using the strengths and opportunities, the weaknesses should be overcome and the threats should be tackled. Some strategies were presented. In order to prioritize these strategies, the quantitative matrix QSPM was used. Finally, the hydrological, economic, social and environmental evaluating strategies of underground dams, before and after the construction, with a final score of 19.3 were prioritized.
D. Ziaei, R. Zare Bidaki, A. A. Besalatpour, A. Malekian,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
To preserve soil as a productive resource, a balance between natural capability and utilization must be established to achieve through land suitability evaluation. The aim of this study was to compare the run-off and deposition of different land uses of Beheshtabad watershed in the current situation and in compliance with standardized land use fitted situation. For this purpose, land use map in its current state was provided using Landsat 7 images and land use suitability map was obtained by FAO (1979) instructions. SWAT model was then applied to simulate runoff and sediment yield by using these land use maps. To do this, the curve number method was used for calculating the runoff, the Muskingam was applied for channel routing, and Hrgrave-samani was employed for potansial evapotranspiration. The results confirmed that considering suitability in using lands in Beheshtabad watershed caused the reduction of the average runoff from 99.4 mm/yr to 82.8 mm/yr (17%) and sediment rate of 10.7 to 7.8 t/ha. yr (27%). Also, the reduction percentage in some land uses, such as dry, irrigated cropland and downstream ranges, was much more.
E. Soheili, H. Malekinezhad, M. R. Ekhtesasi,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
The Kor River in Fars province supplies an important part of water requirement in the Doroodzan dam basin and its surrounding area. In this study, the meteorological and hydrological droughts of this area were investigated in the last four decades. For this purpose, the temporal and spatial trend variability of the stream flow was investigated in monthly, seasonal, and annual time scales in the 6 selected stations. The trends of Standardized Precipitation Index SPI, as the drought index, in the 5 selected stations were also studied by the modified Mann-Kendall method. The results indicated that the trend in the stream flow was decreasing in all time scales. Significant downward trends were observed at 95% confidence level on monthly, annual and monthly time scales, especially in the warm months from May to September. These significant downward trends were located spatially in the stations located near the agriculture area, in the middle part of the basin. The significant upward trend existed only at the Doroodzan dam station, at the outlet in the area and in the warm months of the year. In the case of the SPI index, trends were decreasing in all time scales and were significant only at 2 stations in the long-term periods, 9, 12, and 18 months, at 95% confidence level. The results, therefore, indicated the occurrence of severe droughts (SPI<-2) during 1982-83 and 2007-8 periods.
V. Rahdari, A. Soffianian, S. Pormanafi, H. Ghayomi Mohammadi, S. Maleki, V. Pormardan,
Volume 23, Issue 4 (winter 2019)
Abstract
In this study, to evaluate the rain- fed land capability in the west of Gavkhooni basin and Plasjn sub- basin, a multi- criteria evaluation method was used. First, by reviewing the literature and expert knowledge, proper data were determined. Criteria and constraint were standardized by Fuzzy and Boolean methods repeatedly and the criteria weights were determined using the analytic hierarchy process. Calculated weights showed that soil and climate criteria with 0.27 and 0.26 had the highest weights among other criteria. Criteria and constraints were combined by considering criteria weights and using the weighted linear combination method; then the rain- fed land capability model was prepared. By re- classing the prepared model, the rain- fed land capability map was produced in 6 capability classes. The results showed that 178430 hectares of the study area was related to very high and high rain- fed capability classes. To determine the rain-fed agriculture sustainability, rain- fed agriculture locations were determined in each land rain- fed capability map. The results showed that 19686 hectares of rain- fed areas were located in high and very high capability and 5999 hectares were the in lower classes.
M. Maleki-Kakelar, M. Yavari,
Volume 24, Issue 1 (Spring 2020)
Abstract
Biocementation through microbial induced carbonate precipitation (MICP) is a recently developed new branch in geotechnical engineering that improves the mechanical properties of bio-treated soils. The potential application of MICP to handle problems such as liquefaction and erosion has been established; this technique offers an environmentally friendly, cost-effective and convenient alternative to traditional soil improvement approaches. Nevertheless, in spite of the widespread demonstration of the process at laboratory scale, few field and practical applications have been implemented to assess the efficiency of the biochemical process. Therefore, this paper presents a review of the utilization of MICP for soil improvement and discusses the treatment process including the key constituents involved and the main affecting factors, especially in field scale applications. The major contribution of this research is to identify the main parameters restricting the application of this method on site. Finally, technical and commercial progress in the industrial adoption of the technology and the main challenges that are ahead for the future research prior to real practical application are briefly discussed.
A. Malekian1, A.a. Jafarazdeh, Sh. Oustan, M. Servati,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
To study the soil-landscape change in the Chaldoran region, 9 representative soil profiles were studied in 5 dominant geomorphic units of the study area including piedmont plain, mantled pediment, alluvial fan, plain, and flood plain. The results showed that the accumulation of pedogenic carbonate in some soils was concretion and light in color. In control soils in the piedmont plain (profile 5 and 7), mantled pediment (profile 6), and flood plain (profile 8) clay transferred from the surface horizons and accumulated in the lower horizon, due to relatively good rainfall in the region and distinct dry and wet seasons has led to the formation of argillic horizons along with the formation of crust on the surfaces of aggregates and building units and has formed the Alfisoils order. Mineralogical results showed the presence of chlorite, illite, kaolinite, and smectite minerals. According to the evidence, illite, chlorite, and kaolinite minerals were inherited and smectite minerals were formed due to weathering and evolution of illite, chlorite, or palygorskite minerals. Also, the results of the CIA index in the region indicated that the soils of the region are in the stage of weak to moderate weathering. In general, the results indicated the critical role of drainage, land use, and parent materials in the soils of the study area.
A. Yousefi, M. Maleki-Zadeh, A.r. Nikooie, M.s. Ebrahimi,
Volume 26, Issue 4 (Winiter 2022)
Abstract
This study determines the amount of irrigation water saved as a result of the subsidy policy to adapt from flood to drip irrigation. We developed a positive mathematical programming model (PMP) to evaluate the effect of economic incentives on farmers’ decisions to choose the type of irrigation technology, cropping pattern, and "water use" and "water consumption" in rural Garkan Shomali district, which is part of the Najafabad aquifer. We collected data through farm surveys, desk research, and expert interviews. The results showed that a reduction in the financial costs of converting flood irrigation into drip irrigation can lead to farmers investing in this technology. In the current water allocation scenario, the subsidy policy increases the water consumption of drip-irrigated crops by 28%, of which 19% is non-consumed water before subsidy payment and the rest is related to the reduction of furrow-irrigated lands. Also, under non-volumetric water delivery conditions, the operating costs reduce and the net income of the farms increases because of the increase in efficiency and the development of the area under cultivation, which increases water consumption while the water use is constant. In the volumetric water delivery scenario, with the increase in subsidies, the net income of the farms will increase without developing the area under cultivation and only because of the increased yield. Therefore, subsidy policy increases irrigation efficiency at both the farm and regional levels and is an effective tool for dealing with drought conditions.
