Research Article
H. Seyyed Kaboli; A.M. AkhodAli; A.R. Masah Bavani; F. Radmanesh
Abstract
General Circulation Models (GCMs) have been identifiedas asuitable tool for studying climate change. Butthese models simulate climatic parametersinthe large-scale which has poor performance in the simulation of processes such asrain fall-run off. There fore, several of down scaling methods were developed. ...
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General Circulation Models (GCMs) have been identifiedas asuitable tool for studying climate change. Butthese models simulate climatic parametersinthe large-scale which has poor performance in the simulation of processes such asrain fall-run off. There fore, several of down scaling methods were developed. This researchis presented down scaling model based onk-nearest neighbor (K-NN) non-parametric method. The modelis used to simulate daily precipitation data in Ahvaz station for the next period (2015-2044) under climate change scenarios based on out puts of three General Circulation Models, including HADCM3, NCARPC Mand CSIROMK3.5. The results indicate that them odelhasa high capacity for down scaling data. It is predicted that the frequency of storm is increased with high intensity on future period in Ahvaz station while dry spells will be prolonged.
Research Article
H.R. Samaei; A. Golchin; Mohammad Reza Mosaddeghi; Sh. Ahmadi
Abstract
Organic matter improves soil structure and any factor that decreases soil organic matter content causes soils structural instability. In soils with low organic matter content, soluble polymers can be used to increase the soil structural stability. In order to study the effects of polymer type and concentration ...
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Organic matter improves soil structure and any factor that decreases soil organic matter content causes soils structural instability. In soils with low organic matter content, soluble polymers can be used to increase the soil structural stability. In order to study the effects of polymer type and concentration on physical properties of soils with different texture, factorial experiment ..was ..conducted.. within ..completely ..randomized design ..with ..three replication. Three types of polymer (R790, TC108 and NC218) and three polymer concentration (1:1, 1:3 and 1:10 V/V polymer: water) were used in factorial combinations. Samples from soils with different texture were sprayed with different concentrations of the polymers and physical properties of polymer- treated soil samples were measured and compared with the control. Polymers application significantly enhanced the physical conditions of the soils. It increased the soil saturated hydraulic conductivity and dry and wet structural stabilities of the polymer-treated samples when compared with the control. The application of polymers decreased the dispersible clay and soil density of the polymer-treated soil samples. Increase of the soil saturated hydraulic conductivity and structural stability of the polymer-treated samples was greater for high polymer concentrations. The TC108 and R790 polymers were more effective than the NC218 polymer in improving the physical properties of the soils.
Research Article
L. Ghorashi; Gh. Haghnia; A. Lakzian; R. Khorasani
Abstract
Iron is an essential micronutrient for plant growth. The existence of lime, low content of organic matter and excess application of phosphate fertilizer in soils are the factors affecting its availability. In this study the effects of lime, phosphorus and organic matter on growth and iron uptake of maize ...
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Iron is an essential micronutrient for plant growth. The existence of lime, low content of organic matter and excess application of phosphate fertilizer in soils are the factors affecting its availability. In this study the effects of lime, phosphorus and organic matter on growth and iron uptake of maize were evaluated. A greenhouse experiment was conducted with two levels of lime (0, 2% calcium carbonate) two levels of organic matter (0 , 1% cattle manure),three levels of phosphorus (0, 200, 400 kg ha-1 triple super phosphate). The experimental design used, was completely randomized ,factorial, with 2 replications. Results showed that application of cattle manure significantly increased shoot dry weight, iron concentration and iron uptake of maize. The application of lime had no significant effect on shoot dry weight however it decreased iron concentration and iron uptake of maize. Application of phosphorus increased shoot dry weight but decreased iron concentration and iron uptake of plant. The study of organic matter interaction with one of the other treatments showed that application of organic manure can improve the negative effects of lime and phosphorus.
Research Article
B. Shiranpour; A. Bahrami; M. Shabanpour
Abstract
Due to high organic matter and strong structure, the forest soils in Guilan province are potentially productive. This study was conducted to show the effects of land use change on soil fertility in four different sites in Guilan province where the location of tea garden and forest have the same physiography ...
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Due to high organic matter and strong structure, the forest soils in Guilan province are potentially productive. This study was conducted to show the effects of land use change on soil fertility in four different sites in Guilan province where the location of tea garden and forest have the same physiography and parent material. At any site three soil samples with randomly method were collected from a depth of 20cm from the soil surface and total Nitrogen, available Phosphorous and Potassium, exchangeable form of Calcium and Magnesium contents and C/N ratio were measured. The results showed that after 10 – 40 years of the land use change (forest to tea gardens) the amounts of these elements had been significantly reduced (P>0.01). Also the effect of sites on this reduction had been significant,this means that land use change in different sites had various effect on characteristics that were studied. In contrast, C/N ratio didn’t show significant difference.
Research Article
V. Sarvi Moghanlo; Mostafa Chorom; M. Falah; H. Motamedy
Abstract
Due to widespread distribution, hydrocarbon toxicity and mutagencity, PAHs are listed as hazardous pollutants, and remediation of soils contaminated with PAHs is a major challenge. The use of degrading microorganisms and plants for bioremediation of PAHs-contaminated environments seems to be a viable ...
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Due to widespread distribution, hydrocarbon toxicity and mutagencity, PAHs are listed as hazardous pollutants, and remediation of soils contaminated with PAHs is a major challenge. The use of degrading microorganisms and plants for bioremediation of PAHs-contaminated environments seems to be a viable technology for restoration of polluted sites. The purpose of this research was investigation the effect of mycorrhiza and degrading bacteria in increasing pytoremediation. For this purpose, the soil deliberately contaminated with crude oil in 1 and 2 wt% rate and four treatments: plant multiflorum (T1), plant multiflorum with mycorrhiza inoculation (T2), plant multiflorum with oil degrading bacteria inoculation (T3), plant multiflorum with mycorrhiza and oil degrading bacteria inoculation (T4) were employed for bioremediation of oil contaminated soil. The study results showed that with increasing the level of pollution, shoots and roots yield was decreased. The percentage of AM colonization in mycorrhizal treatments did not significantly reduce the yield. Most importantly, degradation of oil components was significantly enhanced by the addition of oil-degrading microorganisms, compared to remediation of growing plants alone at both level of pollution. The highest oil degradation (85%) was observed with AMF + oil degrading bacteria in soil with pollution level of 2%., GC results indicated that all normal paraffin and isoperopanoids i.e. Phytane and Pristane decreased from 40 to 80 percent in treatments with oil-degrading microorganisms.
Research Article
Y. Abbasi; A. Liaghat; F. Abbasi
Abstract
Suitable management of water and fertilizer is one of the important factors, affecting water and fertilizer efficiency and environmental pollution. In this study, nitrate deep leaching was evaluated in a furrow irrigated experimental field in Karaj. Experiments were conducted in randomized complete blocks ...
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Suitable management of water and fertilizer is one of the important factors, affecting water and fertilizer efficiency and environmental pollution. In this study, nitrate deep leaching was evaluated in a furrow irrigated experimental field in Karaj. Experiments were conducted in randomized complete blocks in free-drainage furrows having 162 m length in 12 experimental blocks. The first factor consisted of 60%, 80% 100% and 120% of required irrigation water and the second factor 60%, 80% and 100% of nitrate fertilizer requirement applied by fertigation method. Nitrogen requirement was determined based on soil analysis and applied in four stages of the crop growth: before cultivation, in seven leaves, shooting and earring stages in which the first part (before cultivation) was applied by manual distribution and other three parts by fertigation. To determine soil nitrate concentrations, soil samples were taken from depths 20, 40, 60, and 80 cm in all of treatments. After air-drying, soil samples were passed through 2 mm sieve. Then, nitrate concentration of samples were analyzed by spectra photometer. Nitrate losses through runoff were measured by sampling of outlet water. Accumulated nitrate in maize was determined by randomized sampling of plants in all treatments. Finally, to determine nitrate leaching, nitrate mass balance was made. Results showed that 120% water level treatment provided 12% water deep percolation from root zone, while 60% water level treatment resulted in 4.5% water deep percolation. Both water and fertilizer levels had pronounced effect on nitrate leaching. The highest nitrate leaching occurred in 100% fertilizer level treatment decreasing by water reduction level. In some cases such as 80% fertilizer level, water level of 60% and 80% didn’t have any effect on nitrate deep percolation. Therefore, water level selection in this situation depends on other factors such as yield. Considering maize as a plant with root depth to be about 80 cm, water and nitrate deep percolation was evaluated up to 80 cm soil depth for all treatments. 60% and 80% water levels did not provide nitrate leaching below the mentioned root zone depth.
Research Article
H. Moradi; H. Ansari; majid hashemi nia; A. Alizadeh; A. Vahidian Kamyad; S.M.J. Mosavi
Abstract
Evapotranspiration is one of the major components of hydrologic cycle and estimation of irrigation needs. In recent years the use of intelligent systems for estimating hydrological phenomena has increased significantly.In this study the possibility of using fuzzy inference system efficiency, creating ...
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Evapotranspiration is one of the major components of hydrologic cycle and estimation of irrigation needs. In recent years the use of intelligent systems for estimating hydrological phenomena has increased significantly.In this study the possibility of using fuzzy inference system efficiency, creating a bridge between meteorological parameters and evapotranspiration, and comparing the accuracy of reference evapotranspiration using these systems were investigated. After analyzing the different models and different combinations of daily meteorological data, five models for estimating daily reference evapotranspiration were presented. For these models, the calculated evapotranspirationfrom Penman-Monteith-FAO equation was considered as a baseand the efficiency of other models was evluated using statistical methods such as root mean squared error, error of the mean deviation, coefficient of determination,Jacovides(t) and Sabbaghet al. (R2/t) criteria. The used data were collected from Mashhad’s meteorological synoptic station for a period of 50-years (from 1339 to 1389).From the available data, 75 percentwas used for training the model and the rest of 25 percent was utilized for the testing purposes. The results derived from the fuzzy models with different input parameters as compared with Penman-Monteith-FAO and Hargreaves-Samani methods showed that fuzzy systems were very well able to estimate the daily reference evapotranspiration.Fuzzy model so that the highest correlation with the four input variables (r=0.99) had in mind and evaluate other parameters, the model with two parameters, temperature and relative humidity (RMSE=0.96, MBE =0.18, R2=0.95, t=22, = and R2 / t=0.04) match very well with the model Penman - Monteith - FAO had stage training. In the test phase, training phase was very similar results and the model with the second phase of temperature and relative humidity will get the best match. According to the results of this study it can be concluded that fuzzy model approach is an appropriate method to estimatethe daily reference evapotranspiration. In addition, the fuzzy models do not require complex calculations which are required forcombination methods.
Research Article
A. Maadani; A. Lakzian; Gh. Haghnia; R. Khorasani
Abstract
High concentration, of heavy metals and the presence of phosphorus in soils may cause a reduction in the growth and activity of arbuscular mycorrhizal (AM) fungi and consequently, the spore production of these fungi would decrease. In order to evaluate the effect of zinc and cadmium as heavy metals and ...
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High concentration, of heavy metals and the presence of phosphorus in soils may cause a reduction in the growth and activity of arbuscular mycorrhizal (AM) fungi and consequently, the spore production of these fungi would decrease. In order to evaluate the effect of zinc and cadmium as heavy metals and phosphorus on arbuscular mycorrhizal fungi activity through measuring glomalin produced by these fungi a factorial experiment arranged as completely randomized design was carried out. Experimental factors included two fungal species G. mosseae and G. intraradices and non mycorrhiza (NM), six combinations of metals (400 mg of Zn, 25 mg of Cd, 400 mg of Zn + 25 mg of Cd, 50 mg P, 50 mg of P+ 400 mg of Zn + 25 mg of Cd, and no metal kg-1 soil sample) in three replications. The results showed that inoculated treatments produced more glomalin compared to non mycorrhizal treatments. The application of Cd, Zn and P caused a significant reduction in produced glomalin by both fungi species. The most reduction of glomalin in G. intraradices was detected in Cd treatment and in G. mosseae was in Zn treatment. The result also showed a positive correlation between the measured glomalin by Bradford assay and the percent of root colonization. According to the results of this study, glomalin in soil could be an indicator to monitor arbuscular mycorrhizal fungi activity and soil health.
Research Article
J. Givi; M.R. Nouri
Abstract
Proper use of agricultural lands is essential because of fast growing population and water stress which occurs in arid and semi-arid regions. In this regards, land suitability evaluation and land production potential prediction are two important prerequisites for land use planning. This research was ...
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Proper use of agricultural lands is essential because of fast growing population and water stress which occurs in arid and semi-arid regions. In this regards, land suitability evaluation and land production potential prediction are two important prerequisites for land use planning. This research was done to compare FAO and Wageningen models which were used in land production potential prediction for irrigated maize and to determine management level around Shahrekord city. For this purpose, first, radiation thermal production potential for irrigated maize was estimated, using FAO and Wageningen models. Then, land production potential was calculated by multiplication of soil index and radiation thermal production potential. Soil index, indicating the extent of soil limitations effective in production reduction, was calculated by the Storie and the second root formulaes. The potential, obtained by the FAO model is higher, compared with that calculated by Wageningen model. This difference is due to difference in calculation method and different forms of the models. The results showed that the land production potential is higher than the observed yield. Management level of the farmers is the origin of this difference. By using two methods, it was proved that management level in most of the land units is high. Determination coefficients of correlation analysis between land production potential and observed yield were obtained as 0.7383 and 0.7850, using FAO model, and as 0.7385 and 0.7775, using Wageningen model, respectively as Storie and second root formulas were used for calculation of soil index. This means that the land production potential and the observed yield have a significant correlation and accuracy of the used methods for estimation of land production potential is acceptable. Factors that increase the determination coefficient are discussed as well.
Research Article
A. Aazami; K. Zarafshani; hossein dehghani; A. Gorji
Abstract
The purpose of this integrative (quantitative-qualitative) descriptive survey study was to determine factors influencing farmers’ attitude toward sprinkler irrigation systems. A researcher made questionnaire was used to collect data. A sample of 274 farmers who were equipped with sprinkler irrigation ...
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The purpose of this integrative (quantitative-qualitative) descriptive survey study was to determine factors influencing farmers’ attitude toward sprinkler irrigation systems. A researcher made questionnaire was used to collect data. A sample of 274 farmers who were equipped with sprinkler irrigation systems during the past three years participated in the study. The face validity of the questionnaire was tested using experts in Department of Irrigation Improvement in Water and Soil Division in Ministry of Agricultural Jihad as well as experts in Agricultural College. Corrections were made in the research instrument as needed. The reliability was tested using a pilot study with 50 farmers outside the population. An Alpha Coefficient of 0.75 proved to be reliable. Results revealed that 80% of farmers held positive attitude toward their irrigation systems. Moreover, farmers’ level of education, experience with the systems, cost if installation, training, changes in income, and land holdings explained 64% of variance in farmers’ attitude toward irrigation systems. The qualitative results revealed some problems and issues perceived by farmers. Long process in filling application, lack of expertise among engineering firms, ineffective training classes, low quality spare parts, lack of water resources, and inefficiency in allocating resources were challenges by most farmers. Since attitude is predicts behavior, the result of this study can assist sprinkler irrigation policy makers to develop irrigation development in the region.
Research Article
F. Bahreini; A. Pahlavanravi; A. Moghaddamnia; Gh. Rahi
Abstract
Desertification and land degradation in arid, semi-arid and sub-humid dry regions, are a global environmental problem. Therefore, accurate assessment of desertification trend will be useful to prevent and eradicate these problems. The study area is located in Daiyer city of Boushehr province. In this ...
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Desertification and land degradation in arid, semi-arid and sub-humid dry regions, are a global environmental problem. Therefore, accurate assessment of desertification trend will be useful to prevent and eradicate these problems. The study area is located in Daiyer city of Boushehr province. In this study, in order to assess land degradation according to local conditions of the study area, two factors of wind erosion and climate were selected as the main factors affecting desertification. Assessment of desertification status in the study area was conducted on basis of these two factors and weighting indices according to the IMDPA model. After separating work units (Geomorphologic facies), numerical value of each index was determined for each work unit, a data layer for each index was prepared and the layer related to each factor was specified by calculating the geometric mean of its indices score. Then, desertification intensity map was created by combination and determination of geometric mean of factors. The results indicated that 31.74% of the studied area falls within the medium class, 62.62% in the severe class and 4.65% in very severe desertification intensity class. Work units 6 and 8 with maximum quantitative values were placed in first priority of degradation. The work units 9, 13, 12, 10, 14, 15, 2, 7, 4, 3, 1, 11 and 5 with minimum quantitative values had lower priorities, respectively. Among the studied indices, two indices of dryness and non- living cover density percentage were the most important factors causing the desertification in this region.
Research Article
S. Rajaei; F. Raiesi; S.M. Seyedi
Abstract
The contamination of ecosystem components with petroleum and its derivatives is considered as one of the most crucial environmental threat in Iran, particularly in southern areas. Bioremediation has frequently been regarded as an appropriate and more practical alternative to clean-up petroleum hydrocarbons ...
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The contamination of ecosystem components with petroleum and its derivatives is considered as one of the most crucial environmental threat in Iran, particularly in southern areas. Bioremediation has frequently been regarded as an appropriate and more practical alternative to clean-up petroleum hydrocarbons in the contaminated environments. Bioremediation optimizes conditions for microbial hydrocarbon degradation and uses the microorganisms and plants potential to metabolize contaminants resulting in their removal or attenuation in situ. This study aims at remedying an aged petroleum-contaminated soil using bioaugmentation and phytoremediation techniques. A consortium has been prepared using oil-degrading bacteria; 10% oil-contaminated soil was then inoculated with the consortium. Additionally, oat and/or barley were planted in certain treatments to separately evaluate the effects of plant-bacteria interaction on Total Petroleum Hydrocarbon (TPH) degradation and inoculum's efficiency. TPH degradation value under unplanted and uninoculated conditions was only 2.4% in the studied petroleum -contaminated soil after 4 months. However, the presence of the two plants elevated TPH degradation up to 30%, and bacterial inoculation resulted in only 20% TPH degradation. The significance of the plants in enhancing TPH degradation could be probably explained by promoting microbial populations, growth and activities. The highest amount of TPH degradation recorded was 44% and was observed with inoculated plants. The presence of plants in petroleum-contaminated soils promoted microbial populations and activities with increased microbial respiration and biomass well developed petroleum-degrading microbial population and decreased microbial metabolic quotient (qCO2), hence, increased biodegrading of hydrocarbons.
Research Article
A. Shabani; Gh. haghnia; Ali reza Karimi; M.M. Ahmadi
Abstract
Topographic characteristics are considered as important factors for growth and yield of rainfed crops because of the impact on the water distribution and consequently effects on soil physical and chemical properties. No information is available on this subject for North Khorasan province of Iran. The ...
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Topographic characteristics are considered as important factors for growth and yield of rainfed crops because of the impact on the water distribution and consequently effects on soil physical and chemical properties. No information is available on this subject for North Khorasan province of Iran. The purpose of this study was to investigate the effect of soil and topographic characteristics on the rainfed wheat yield in Sisab region of North Khorasan province. Surface soil samples and wheat yield data were taken from 100, 1×1 m2 plots on different slope positions from 800 ha of rainfed farms. Sand, silt, clay, gravel, calcium carbonate equivalent, soil organic matter, pH, EC, total nitrogen, available potassium and phosphorus were measured. Primary and secondary topographic derivatives including elevation, slope, aspect, plan curvature, topographic wetness index, sediment transport index and stream power index were calculated from a 30m grid cell size digital elevation model. Multiple regression models were developed between soil and topographic characteristics and yield components. 20 out of 100 samples were used to validate the model prediction. Coefficients of correlation matrix showed that elevation and calcium carbonate equivalent have the strongest correlation with wheat yield components. Soil factors including calcium carbonate percentage and organic matter and topographic indices such as elevation, slope and stream power index were entered into the regression models. Because of non-linear and complex interrelation, the regression models explained only 43% and 40% of total and grain yield variations, respectively. The results of this study showed that although Sisab is located on the border of arid and semiarid climate, the topographic characteristics could affect soil properties and wheat yield components.
Research Article
A. Masoodi; P. Parsamehr; F. Salmasi; S. Pureskandar
Abstract
Compound broad-crested weir, have a small inner rectangular section for measuring low flows and then, they broaden to a wide rectangular section at higher flow depths. This paper presents data that will be of use in the design of hydraulic structures for flow control and measurement. A series of laboratory ...
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Compound broad-crested weir, have a small inner rectangular section for measuring low flows and then, they broaden to a wide rectangular section at higher flow depths. This paper presents data that will be of use in the design of hydraulic structures for flow control and measurement. A series of laboratory experiments was performed in order to investigate the effects of length of the lower weir crest and step height of broad-crested weirs of rectangular compound cross section on the values of the discharge coefficient. For this purpose, 15 different broad-crested weir models with rectangular compound cross sections for a wide range of discharges tested. Multiple regression equations based on dimensional analysis theory were developed for computing discharge coefficient. The results of compound broad-crested weirs were compared with Genetic programming (GP) and Artificial neural network (ANN) and it was found that the ANN formulation of the problem of solving for the discharge coefficient is less successful than that by GP. The implementation of GP offers another formulation for discharge coefficient.
Research Article
Abstract
Regional flood analysis is a conventional method for estimation of flood design in ungauged site which its accuracy relates the how much homogeneity is among the stations that used in regional flood frequency. Cluster method is commonly used to regionalization of stations which its accuracy is dependent ...
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Regional flood analysis is a conventional method for estimation of flood design in ungauged site which its accuracy relates the how much homogeneity is among the stations that used in regional flood frequency. Cluster method is commonly used to regionalization of stations which its accuracy is dependent on identifying the effective basin variables and their weight that it commonly can't accessible. In this research, Canonical Correlation between basin and flow variables was used to identify the region of ungauged site. In this method the pair canonical variables and its relations are able to determine the similarity of stations. This method was applied to Ouroumieh Lake basin and results shown that created homogeneous region of ungauged sites using Canonical Correlation method has more stations and the error of design flood estimation in ungauged sites is low in compare the cluster method
Research Article
E. Iranshahr; E. Sepehr
Abstract
A factorial completely randomized design experiment with three replications was carried out in greenhouse to evaluate the phosphorus (P) acquisition and utilization efficiency of 20 wheat genotypes in a river sand fertilized with rock phosphate (RP) and soluble P (PS). Results showed significant differences ...
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A factorial completely randomized design experiment with three replications was carried out in greenhouse to evaluate the phosphorus (P) acquisition and utilization efficiency of 20 wheat genotypes in a river sand fertilized with rock phosphate (RP) and soluble P (PS). Results showed significant differences in shoot dry weight (SDW), shoot P concentration, shoot P content, P acquisition (PACE), P utilization (PUTE) and P efficiency. Marvdasht and Hamun with 8.3 and 5.6 g dry weight showed the highest and lowest response to soluble P fertilizer application, respectively. The average of PACE for all genotypes was 0.04 which Azadi and Karaj1 were the most and least efficient in P acquisition compared to other genotypes. PUTE ranged from 0.6 (Azadi) to 1.12 (Moghan 1) with the average of 0.82 (RP) and 0.31 g DW mg-1 P (PS). Among wheat genotypes, Karaj 1 (4.5%) and Azadi (14.5%) showed the lowest and highest P efficiency, respectively. There was no correlation (R2=0.18) between P efficiency and shoot P concentration of genotypes, but the relationship between P efficiency and shoot P content was highly significant (R2=0.77).
Research Article
B. Fallahi; A. Fakheri Fard; yaghoub dinpazhoh; S. Darbandi
Abstract
Having a correct view of the effective factors on climatic changes by explanation of a considerable part of the total variance in data with limited number of principal components the analytical methods of decreasing data dimensions, such as PCA are important tools in water resources planning. In this ...
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Having a correct view of the effective factors on climatic changes by explanation of a considerable part of the total variance in data with limited number of principal components the analytical methods of decreasing data dimensions, such as PCA are important tools in water resources planning. In this study PCA method as a projection tool for projecting the information space on the limited and specific axes, ward’s method as a hierarchical clustering and k-mean as partitioning clustering method has been applied in this research. Using this methods and application of daily precipitation data of 60 meteorological stations during a 35 years period (1970-2004), 4 types of delineated regions were come out on the basis of daily precipitations, distance-quantity index, time intervals and rainy days series. S statistic test algorithm was used for homogeneity test of the regions. Results showed the nature of the PCA method is such that projects the data space on the main axes and shows the real space. But in the hierarchical methods, clusters do not describe the real structure. Therefore we do expect that the resulting clusters of PCA would be more realistic than that of methods. But hierarchical methods have the advantage of containing the wider clustering information on the basis of homogeneity than the others.
Research Article
M.H. Najafi Mood; A. Alizadeh; K. Davari; M. Kafi; A. Shahidi
Abstract
This experiment was conducted based upon a factorial split plot design consisting of three factors: salinity with three levels (2.2, 5.5 and 8.3 dS/m), irrigation with four levels (50%, 75%, 100% and 125%), cultivars with two levels (Varamin and Khordad). There were three replicates for each treatment ...
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This experiment was conducted based upon a factorial split plot design consisting of three factors: salinity with three levels (2.2, 5.5 and 8.3 dS/m), irrigation with four levels (50%, 75%, 100% and 125%), cultivars with two levels (Varamin and Khordad). There were three replicates for each treatment combination. Salinity was considered as main plot while the other factors were arranged as sub plots in the experiment. Effects salinity and deficit irrigation on yield for cultivars of cotton studied with Marginal Production(MP), Marginal Rate of Technical Substitution(MRTS) and Value of Marginal Production(VMP) indexes. Also for economics analysis, optimum depth of irrigation for deficit irrigation and complete irrigation depth were determined for tow cultivar. MPI showed That in deficit irrigation condition, yield of Khordad less than Varamin, for 1 centimeter of irrigation depth. But in over irrigation level , decreasing yield of Khordad rather than Varamin. Also MPECw showed, That yield decreased 31.8 Kg/ha on Varamin and 76.5 Kg/ha on Khordad cultivars, by increasing 1 dS/m salinity of irrigation water. MRTS index showed for instant yield, when salinity of irrigation water decrease 1 dS/m, must be increase depth of irrigation, 1.68, 3.85 cm for Varamin and Khordad respectively. So that, in equal situation of irrigation water salinity, optimum irrigation depth for Khordad was rather than Varamin.Also in all of salinity levels, optimum irrigation depth, for Khordad was rather than Varamin.
Research Article
S.A. Ghassemi; Sh. Danesh
Abstract
In this research a fuzzy decision making model was presented to assess and rank various water desalination methods and ultimately select the best alternative. The desalination alternatives which were investigated included Reverse Osmosis, Electrodialysis, Multi-Stage Flash Distillation, Multi-Effect ...
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In this research a fuzzy decision making model was presented to assess and rank various water desalination methods and ultimately select the best alternative. The desalination alternatives which were investigated included Reverse Osmosis, Electrodialysis, Multi-Stage Flash Distillation, Multi-Effect Distillation, Vapor Compression and Ion Exchange. The model was carried out in three steps: problem definition, fuzzy computations and ranking of alternatives. The hierarchy structure used for problem definition included 5 levels of: goal, main criteria, sub-criteria, factors, and desalination alternatives. The criteria, sub-criteria and factors and the relative importance of each were determined based on the experts' opinions and the literature results. In the next step, by using Chang's extent analysis, various desalination alternatives were evaluated on the basis of the selected criteria, sub-criteria and factors. For assessment of accuracy and its practical application, the model was used in a case study concerning quality management of the brackish water from a number of wells located in the City of Torbat-e-Heydaryieh. The results of the research indicated that the Electrodialysis process, with the final weight of 0.255, was the best method of desalination for the investigated wells. The sensitivity analysis also showed that the fuzzy model has a low degree of sensitivity in regard to the changes in criteria weights, meaning that the results are adequately reliable. The results furthermore pointed out that the fuzzy analytical hierarchy process can be used as an efficient tool for systematic decision making in the area of qualitative water resource management.
Research Article
A. Shahnazari; Mirkhaleg Ziatabar Ahmadi; ghassem aghajani mazandarani
Abstract
Rice is the most important agricultural product in the world after wheat, and Iran has a special place in producing almost two million tones of rice per year. Considering the drought crisis and high consumption of water in paddy fields, it is useful to present strategies in order to increase irrigation ...
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Rice is the most important agricultural product in the world after wheat, and Iran has a special place in producing almost two million tones of rice per year. Considering the drought crisis and high consumption of water in paddy fields, it is useful to present strategies in order to increase irrigation efficiencies. In this respect, many paddy fields in Northern Province of Iran are Land Leveled. The effect of these fields on the Water Balance Parameters, water use efficiency and water productivity has been used in this study. This research has been carried out in Qaemshahr City, Mazandaran Province, comparing two traditional and leveled paddy fields measuring 1.9 and 5.67 hectares, respectively for early-ripening local Tarom species. The water discharge rates of input and output, with 3-inch Parshall Flumes were measured. Three lysimeters were tried in order to determine evapotranspiration and deep percolation. The results demonstrate that in traditional and leveled paddy fields, water use efficiencies turned to be 62.9 and 73%, water productivity of 0.476 and 0.575 kilogram per square meter, evapotranspiration of 468.2 and 477.5 mm, and deep percolation of 196.3 and 147.8 mm, respectively. Also, 25% reduction of deep percolation parameter was observed in land leveled condition which was due to hard pan creation and can be known as the most important factor of 10% increase in irrigation efficiency.
Research Article
H. Mohammadzadeh; S. Ebrahimpoor
Abstract
Zarivar Lake, located in west of Marivan -Kurdistan province, is an important natural freshwater body in Iran. Therefore, it is essential to investigate and to protect the water resources of the lake's catchment area. In this research, to develop the Marivan meteoric water line (MMWL - δ18O vs. δ2H), ...
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Zarivar Lake, located in west of Marivan -Kurdistan province, is an important natural freshwater body in Iran. Therefore, it is essential to investigate and to protect the water resources of the lake's catchment area. In this research, to develop the Marivan meteoric water line (MMWL - δ18O vs. δ2H), to determine the surface (lake) and groundwater interactions, to investigate the factores effecting on water quality, and to find out the origin of cations and anions, water samples (rain, lake and ground waters) were collected during measurements of fild parameters (TDS, EC, pH and T ). Based on isotope results, the MMWL is obtained as δ2H = 7.5 δ18O + 9.0 and the average δ18O values of rain, groundwater and lake water are -8.3‰, -7.0‰ , and 5.5‰ , respectively, and δ2H values of these waters are -53.6‰, -42.2‰ , and 16.9‰ , respectively. Isotopic results also indicate that the origin of groundwater resources is meteoric water with minor evaporation lost, however, the lake water showes relatively high evaporation lost. The d-excess indicates that the influence of the Mediterranean water masses on this area. Bsed on hydrchemical results it seems that the composition of both groundwater and lake water is attributed to natural rock-dissolution proccesses, with anthropogenic sources (fertelizers, waste water, etc.) for some ions (Cl-, SO42) in the lake water. Mineral saturation indexes indicate the existence of very low amount of evaporative minerals, and low retention time of water within the aquifer. Cluster analysis of water quality parameters and sampling locations shows similarity amoung all groundwater samples taken around the lake. In addition, all lake water samples also have similar quality, except samples taken from North and South of the lake, and groundwater discharges into the lake from the North West area. The results of factor analysis indicate that three factors controlling about 83.3% of total sample variations.
Research Article
H. Aryanpour; Mehdi Shorafa; A. Liaghat
Abstract
As far as soil moisture is a function of soil structure and texture any changes on these properties changes the soil moisture content. In this study for finding the soil moisture content at field capacity and permanent wilting point for cultivated soil, point pedotransfer functions of non cultivated ...
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As far as soil moisture is a function of soil structure and texture any changes on these properties changes the soil moisture content. In this study for finding the soil moisture content at field capacity and permanent wilting point for cultivated soil, point pedotransfer functions of non cultivated of the same soils were used. For this purpose 64 soil samples from cultivated and non cultivated were chosen in Abyek Qazvin area. Then available soil properties such as particle size distribution, bulk density, organic carbon, calcium carbonate, cation exchang capacity and PH of soils were measured. The soil moisture at FC and PWP. For non cultivated soil were determined by peresure plates. After that point pedotransfer functions were established. With using these functions the moisture of cultivated soils were predicted and compared with the measured ones. The results showed that this functions had overestimated moisture for FC and underestimated moisture for PWP. In fact cultivation reduses soil ability in moisture preservation. Correlation coefficient between measured and predicted moisture for cultivated soils at PWP was more than FC.
Research Article
S. Nezami; S. H Nemati; H. Aroiee; A. Bagheri
Abstract
Although mint species are very sensitive to water deficit stress, but their reaction may be different to reduction of water in soil during growing season. In order to evaluate response of three Mentha species to water deficit stress, an experiment was carried out in a factorial-randomized design with ...
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Although mint species are very sensitive to water deficit stress, but their reaction may be different to reduction of water in soil during growing season. In order to evaluate response of three Mentha species to water deficit stress, an experiment was carried out in a factorial-randomized design with five replication in controlled conditions and Mentha longifolia (wildmint), Mentha spicata (spearmint) and Mentha piperita (peppermint) species were subject to four soil moisture regimes (100, 80, 60, 40 of field capacity (FC)). Plants were on 70% of flowering at the harvest time. Characteristics were included percent of survival, number of total branches and stolon, number of leaf, length of total branches, green area and total dry matter. The results showed that soil moisture treatments had significant effect on survival of three mint species, because spearmint’s survival was 100 in 60 FC, while in wildmint and peppermint were decreased to 70 percent. In peppermint number of total branches and stolon were significantly excel as compare as two other species, however in spearmint number of total leaf, green area and total dry matter were more than two other species, whereas length of total branches in wildmint were higher than spearmint and peppermint. Spearmint had the greatest dry matter in 100 percent of FC and reduction of soil moisture to 80 percent of FC caused 35 percent reduction in previously mentioned parameter, while in wildmint and peppermint 62 and 56 percent reduction were observed, respectively. However spearmint was more tolerant than two other species to water deficit stress, but more study must be achieved for better understanding of mint responses to water deficit stress
