Research Article
A. Biari; A. Gholami; H. Asadi Rahmani
Abstract
Abstract
Soil beneficial microorganisms such as plant growth promoting rhizobacteria (PGPR) are able to enhance plant growth. The research was conducted using a randomized complete block design as split plot factorial with three factors (nutrient management, Azospirillum and Azotobacter strains) .In ...
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Abstract
Soil beneficial microorganisms such as plant growth promoting rhizobacteria (PGPR) are able to enhance plant growth. The research was conducted using a randomized complete block design as split plot factorial with three factors (nutrient management, Azospirillum and Azotobacter strains) .In this experiment the effect of Azospirillum and Azotobacter inoculation on yield and yield components of maize was evaluated in a field trial. Azotobacter levels were A0: no inoculation, A1: Azotobacter sp.Strain5 ، A2: Azotobacter chroococcum DSM2286 and Azospirillum levels were Z0: no inoculation, Z1: Azospirillum sp.Strain21, Z2: Azospirillum lipoferum DSM 1691, Z3:Azospirillum brasilense DSM1690. Results of this study showed inoculation with Azotobacter had significant effect on grain yield, stem and total dry weight, plant height and leaf area as well as 100 seed weight. The same results were obtained with Azospirillum inoculation. The interaction between two bacteria on grain yield, 100 seed weight, number of seed per ear, ear diameter, stem, leaf and total dry weight, plant height, leaf area and nitrogen uptake in seed were significant.
Keywords: Maize, PGPR, Azotobacter, Azospirillum, Yield
Research Article
H. Ahmadi; T. Mesbahzadeh
Abstract
Abstract
In this research sand drifts potential using sand rose graph software and Fryberger velocity classes’ method investigated. Thus Wind data between 1985 and 2005 from meteorological stations of Jask and Kerman were analyzed to examine sand drift potential. Sand drift potential amount of Kerman ...
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Abstract
In this research sand drifts potential using sand rose graph software and Fryberger velocity classes’ method investigated. Thus Wind data between 1985 and 2005 from meteorological stations of Jask and Kerman were analyzed to examine sand drift potential. Sand drift potential amount of Kerman station was 412.6 using sand rose graph and 401.09 using Fryberger,s method. Sand drift potential amount of Kerman station using sand rose graph and Fryberger,s method was 979.2 and 490.51 (v.u) respectively. The calculated values of sand drift potential by two methods showed that there is a little difference between two methods while about Kerman station the calculated values with software is more than Fryberger, s method because this method do not account the speed more than 40 knot .Also, the velocity values has been considered normal in Fryberger,s method while velocity values in one class are not normal, and we can't attribute one number to whole of velocities in each class.
Keywords: Wind erosion data, Fryberger,s method, Sand rose graph software, Drawing sand rose
Research Article
S.K. Mousavi; M. Faizian; A. Ahmadi
Abstract
Abstract
In order to evaluate the effect of different nitrogen application methods on yield and yield components of winter wheat, a field experiment with split plot arrangement in completely randomized blocks design with four replicates was conducted in 2006. Basal dressing in three levels (1- with ...
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Abstract
In order to evaluate the effect of different nitrogen application methods on yield and yield components of winter wheat, a field experiment with split plot arrangement in completely randomized blocks design with four replicates was conducted in 2006. Basal dressing in three levels (1- with no basal dressing, 2- strip and 3- distributing nitrogen fertilizer) as main plot and top dressing in six levels (1- distributing on tillering, 2- two distributing on tillering and before spike appearance, 3- foliar application of fertilizer along with herbicide on tillering and before spike appearance, 4- foliar application of fertilizer on tillering and before spike appearance, 5- two applications: one distributing on tillering and one foliar application before spike appearance and finally, 6- three foliar application of fertilizer on tillering, before spike appearance and milking period) as subplot were carried out. The amount of fertilizer in strip, and all compartmented applications were two thirds of distributing fertilizer method. The highest biomass was recorded in distributing fertilizer (19090 kg ha-1) which was greater 14 and 28 percent in comparison with strip application and no basal dressing, respectively. The highest number of grain per spike belonged to band application of basal nitrogen fertilizer, that was significantly higher than two other treatments. Distributing fertilizer produced the highest grain yield (8525 kg ha-1); however, its differences with strip application was not statistically significant. Top dressing affected grain yield and the greatest yields was observed in one stage distributing, two stage distributing, distributing plus foliar application fertilizing and two stage foliar application fertilizing with herbicide. Grain production in these treatments was statistically greater than two and three stage foliar application of nitrogen fertilizer. The grain protein percent for no basal dressing was significantly lower than broadcasting nitrogen application. The grain protein percent for one stage distributing of top dressing nitrogen fertilizer was significantly higher that other treatments. Based on this research findings, with combined and split application strategies can achieve high yield while saving in nitrogen fertilizer usage.
Keywords: Wheat, Yield, Yield component, Nitrogen fertilizer application methods
Research Article
A. Akhgar; K. Khavazi; N. Khakipoor
Abstract
Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom ...
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Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom and Qazvin provinces. 105 strains were selected from the soil rhizosphere of Canola. According to the growing abilities of the strains in the minimum media of DF having ACC, as the only source of nitrogen, it was determined that 14 strains had the ability to produce ACC deaminase. Identification of strain was carried out according to Bergey’s manual criteria. Results indicated that all the strains belonged to the group of fluorescent Pseudomonads. According to the tests, related to strain determination, 14 strains were identified as P. fluorescent. Measuring ACC deaminase activity showed that the activity of this enzyme in the isolated strains differed from 1.43 to 8.17 μmol α-ketobutyrate/mg/hr. Also the isolates produced IAA in TSB medium between 0.8 – 2.17 μmol/ml. In the present study, effect of selected strains on reducing negative effects of salinity on Canola seedlings growth was evaluated under greenhouse conditions. Under salinity stress, all ACC deaminase producing strains were able to increased canola growth parameters containing shoot fresh and dry weight, shoot and root length. Among tested strains, P12 was the most effective. There was a high correlation between root length and dry matter, and the activity of ACC deaminase producing bacteria. Also with increase salinity from 6 to 8 dS/m, shoot fresh weight and stem length were significantly decreased.
Keyword: ACC deaminas, Pseudomonas, Canola, Salinity
Research Article
M. Mohammadi San; A.R. Astaraei; A. Fotovat; A. Lakziyan; M. Taheri
Abstract
Abstract
With increasing population, Mine activities for metal proceeding are also increasing, so environment will be influenced by contaminant especially heavy metals. In situ immobilization of heavy metals using inexpensive amendments is considered as a simple and cost-effective approach for reducing ...
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Abstract
With increasing population, Mine activities for metal proceeding are also increasing, so environment will be influenced by contaminant especially heavy metals. In situ immobilization of heavy metals using inexpensive amendments is considered as a simple and cost-effective approach for reducing heavy metal contamination. In this research we used sequential extraction for assessing reduction in availability of heavy metal in lead and zinc mine waste (bama mine around Isfahan). The effects of chemical amendments consist of 3 level of Zeolite 0 (Z1), 5% (Z2) and 10% (Z3) and 3 level of Triple Super Phosphate 0 (P1), 0.25% (P2) and 0.5% (P3) on speciation of Pb, Zn and Cd was investigated by sequential extraction based on tesier method. Total concentration of Pb, Zn and Cd were 2300, 16500 and 27.4 mgkg-1 d.m. Result showed that TSP transform heavy metal specially Pb from exchangeable and carbonate fractions to residual and organic, sulfides fractions. Zeolite also transformed Pb and Zn from carbonate fraction to residual fraction. But eth effect of phosphorous was superior to zeolite. There was no interaction between Zeolite and TSP.
Keywords: Soil pollution, Heavy metals, Fractionation, In situ immobilization
Research Article
M. Bahrami Yarahmadi; M. Shafai Bejestan
Abstract
Abstract
In all river engineering projects, determination of flow resistance is essential. Most commonly, the Manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. Over the past decades little or no study has been conducted to ...
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Abstract
In all river engineering projects, determination of flow resistance is essential. Most commonly, the Manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. Over the past decades little or no study has been conducted to investigate the effects of particle shapes on Manning roughness coefficient. Therefore, it is the purpose of this study to see how and by what extend, the particle shape can affect the Manning’s coefficient. To do so three different sediment shapes (angle rounded particles and crushed particles and spherical artificial particles); each in 11 different sizes were collected and tested under different flow conditions. Tests conducted in a flume of 10 meter long, 25 cm wide, 50 cm height and constant bed slope of 0.0005. The results show that the effect of particle shape in larger particle size is less compare to the smaller particle size. As in sediments with size of 11 mm, values of Manning roughness coefficient ( ) for sediment particles shows great difference and in 21mm and 27 mm sediment particles, the Manning roughness coefficient ( ) in angle rounded and spherical artificial particles are equal nearly as the average difference between Manning's coefficient ( ) of these particles are found to be in the order of +1.65 percent and values of Manning roughness coefficient ( ) for crushed particles in 21mm and 27 mm sediment particles shows little difference with other sediment particles. The average difference between Manning's coefficient ( ) of crushed particles with natural rounded particles are found to be in the order of -6.2 percent.
Keywords: Flow resistance, Relative roughness, Manning roughness coefficient, Sediment particles.
Research Article
H. Etesami; H.A. Alikhani
Abstract
Abstract
Now, it’s completely proved that we can find strains among many strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production (IAA), in addition of their ability in N2 fixation .therefore, the aim of this research is to determinate ...
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Abstract
Now, it’s completely proved that we can find strains among many strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production (IAA), in addition of their ability in N2 fixation .therefore, the aim of this research is to determinate the ability of IAA production of some of the indigenous rhizobial strains by two quantitative and qualitative methods. The results obtained from this study show that Rhizobial bacteria enable to produce auxin hormone (IAA). Moreover, this ability is not the same among various rhizobial species and among the strains belonging to each rhizobial species (p3), Rhizobium leguminosarum bv. Viciae (with HD/CD = 2.5 – 3) and Sinorhizobium meliloti (with HD/CD = 2 – 2.5) had the same production ability in both methods and also the strains of Mesorhizobium ciceri (with HD/CD= 1.5 – 2) and Bradyrhizobium spp (with HD/CD= 1 – 1.5) produced the small amount of IAA in both two methods.
Keywords: Rhizobbium, PGPR, IAA, Auxin, Tryptophan
Research Article
F. Abbasi; M. Asmari
Abstract
Abstract
In this paper, we modeled the climate of Iran for future periods. Each period is a 30-years period centered on a year. The range of periods is from 2000 (i.e., 1986-2015) to 2100 (i.e., 2086-2115). This was made using 2 General Circulation Models (ECHAM4 and HadCM2) and 18 IPCC scenarios. MAGICC-SCENGEN ...
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Abstract
In this paper, we modeled the climate of Iran for future periods. Each period is a 30-years period centered on a year. The range of periods is from 2000 (i.e., 1986-2015) to 2100 (i.e., 2086-2115). This was made using 2 General Circulation Models (ECHAM4 and HadCM2) and 18 IPCC scenarios. MAGICC-SCENGEN was used as a tool for downscaling GCM low resolution output data. Result of HadCM2 model shows a % 2.5decrease in precipitation until 2100 but ECHAM4 shows a %19.8 increase for this period. Another difference between results of these 2 models is that HadCM2 predicts an increase in precipitation in next decades for Mazandaran, Golestan, Khorasan Shomali, Khorasan Razavi, Semnan, Tehran and some parts of Gilan and Ghazvin provinces, while ECHAM4 predicts a decrease for that regions. HadCM2 predicts precipitation decrease for southeast of country (Hormozgan, Kerman, Bushehr, south of Fars and some parts of sistan va Baloochestan, but in ECHAM4 that regions will have precipitation increase in similar period. About temperature, both HadCM2 and ECHAM4 agree in temperature increase in next decades for all provinces. These 2 models predict, on the average, 3 to 3.6c increases in temperature until decade 2100. Maximum increase in decadal temperature in ECHAM4 is about 1c more than HadCM2 and both of them are in conformity with each other in spatial distribution of decadal temperature.
Keywords: Magicc-Scengen, General Circulation Model, HadCM2 ,ECHAM4, Climate Change
Research Article
ahad faalian; M. Abolhasani Zeraatkar; A. Lakziyan; A. Akhgar
Abstract
Abstract
Incorporation of plant residues in soils is an important agricultural practice for maintaining soil fertility under organic management systems. Plant residues quality, soil physical and chemical properties, and the microbial population diversity of soils are the most important factors influencing ...
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Abstract
Incorporation of plant residues in soils is an important agricultural practice for maintaining soil fertility under organic management systems. Plant residues quality, soil physical and chemical properties, and the microbial population diversity of soils are the most important factors influencing the decomposition of added organic matter to soils. Decomposition rate of municipal wastes compost, vermi compost, manure and pistaco compost was studied in two soil samples with contrasting texture, two herbicides and three salt concentrations under laboratory condition. Soil moisture was adjusted at 50% water holding capacity and soil samples were incubated at 28 oC. The CO2 production was used as an index for decomposition rate of organic matter. Result showed that decomposition rate of pistaco compost is higher than those municipal wastes compost of vermi compost and manure. The CO2 evolution concentration and the rate of organic matter decomposition followed , and equations, respectively. A positive correlation was found between the rate of organic matter decomposition and K value. The results also showed that high decomposition rate based on K value, belong to pistaco compost, manure, municipal wastes compost and vermi compost, respectively.
Keywords: Organic matter, Decomposition rate, Soil texture, Soil salinity, Pistaco compost
Research Article
S.M. Hosseini; M. Kholghy; B. Ataie Ashtiani; M.M. Bagheri Mohagheghi
Abstract
Abstract
The aim of this study is laboratory investigation of nitrate reduction in water using Fe/Cu nano particles. In this regards, nano Fe0 (54±4 nm) and Fe/Cu particles (75±3 nm) was synthesized and characterized by X-ray diffraction pattern (XRD), scanning electron microscope (SEM) and transmission ...
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Abstract
The aim of this study is laboratory investigation of nitrate reduction in water using Fe/Cu nano particles. In this regards, nano Fe0 (54±4 nm) and Fe/Cu particles (75±3 nm) was synthesized and characterized by X-ray diffraction pattern (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) photographs. The effects of coating load of nano-Fe0 by Cu (0, 5, 10, 15 and 20 % Cu/Fe0 w/w) in nitrate reduction process and chemical reaction modeling of nitrate degradation were carried out in batch experiments. In addition, the effect of initial acidity of solvent (pH= 3, 4, and 5) were investigated on the rate of nitrate reduction in which the initial nitrate-N concentration of solution was 200 mg l-1. All experiments have been carried out in presence of different ions in water. Results indicated that applying only 5% w/w of Cu has higher efficiency in the long-term degradation of nitrate-N. Also, less initial pH of solvent results more removal rate of nitrate. Chemical reaction modeling indicated that process of nitrate-N reduction by bimetallic Fe/Cu nano particles didn’t follow by first order reaction model.
Keywords: Nitrate Reduction, Bimetallic Nano Particles, Domestic Water, Fe/Cu Particles, Chemical Reactions
Research Article
M. Zarei; M. Habibnejad; K. Shahedi; M.R. Ghanbarpour
Abstract
Abstract
Major of hydrological systems are very complicated and it is not possible to understand them completely, therefore simplification is necessary to understand or control of a part of the system behavior such as water balance relationships. Hydrological models are simple structure of complicated ...
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Abstract
Major of hydrological systems are very complicated and it is not possible to understand them completely, therefore simplification is necessary to understand or control of a part of the system behavior such as water balance relationships. Hydrological models are simple structure of complicated systems in water cycle in the nature. The first goal of a hydrological model is function predict of complicated system and survey the impact of any kind of changes on system behavior. In this research IHACRES hydrological model was used to daily flow simulation and calculation of rainfall measure that be increase into streamflow, in the kasilian catchment (Area=342.86 km2) and kasilian sub catchment (Area=67.8 km2). The results was representative of delay naught between rainfall and flow in two catchments, also to values of two parameter coefficient of determination (D) and average relative parameter error (ARPE), the model streamflow in kasilian catchment more accuracy simulated than kasilian sub catchment. Altogether, in attention to values of error in flow volume (Bias), average of simulated streamflow by IHACRES model was more than observed streamflow in these catchments. Percentage of rainfall that bears hand to streamflow creation of kasilian catchment was calculated near third of catchment rainfall average and in the kasilian sub catchment for evaluation and calibration period 231 and 216 mm/yr, respectively.
Keywords: Hydrological Model, IHACRES, Calibration, Evaluation
Research Article
H.R. Motaghian; J. Mohammadi
Abstract
Abstract
The effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a ...
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Abstract
The effect of land use type on soil functioning within an ecosystem can be assessed and monitored using soil quality attributes. Such studies, which are carried out to create a balance between the biological production and the maintenance and improvement of land resource quality, provide a framework for land degradation control and also for identification of sustainable management. In this research investigated the effect of different land uses on soil physical quality indices. Three land uses including a natural pasture, dryland farming and irrigated farming were selected. From natural pasture 54 samples, dryland farming 40 samples and irrigated farming 17 samples were collected in the surface soil (0-15cm). Saturated hydraulic conductivity, infiltration rate, bulk density, soil distribution size, soil erodibility index, organic carbon and water aggregate stability (three classes) were determined for each land use. The results showed that mean, minimum and maximum of saturated hydraulic conductivity in irrigated farming land use is more than others land uses. Water aggregate stability index the macroaggregates (>2 mm) in irrigated farming land use is lower than others land uses. In the among studies variables, saturated hydraulic conductivity, clay percentage, soil erodibility index and water aggregate stability in macroaggregates in different land uses are significant differences in 5% level. Soil erodibility index and water aggregate stability for macroaggregates seems to be the most reliable soil quality indices for the area.
Keywords: Water aggregate stability, Soil quality index, Soil erodibility index
Research Article
A.A. Montazar; N. Pashazadeh
Abstract
Abstract
The main objective of this paper is to apply the CANALMAN model in the performance assessing of different water operational scenarios in the west main canal of Dez irrigation network. The proposed model was calibrated and validated based on the real data of March and April 2006. The real water ...
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Abstract
The main objective of this paper is to apply the CANALMAN model in the performance assessing of different water operational scenarios in the west main canal of Dez irrigation network. The proposed model was calibrated and validated based on the real data of March and April 2006. The real water operational condition during five months (May to September 2006) was simulated. For this period, the mean value of delivery efficiency, adequacy, equity, and reliability performance indicators was estimated 0.669, 0.881, 0.271, and 0.238, respectively. Hence, the delivery adequacy and equity had a moderate status and efficiency and reliability of delivery had a weak status. The results indicated that the night-time closure scenarios may be improved the water distribution status in the canal. During of a 15 days simulation, water saving for night closure scenario 1 and 2 was estimated 11.23% (0.92 MCM) and 8.31% (0.68 MCM), respectively, of water delivered to the canal which can be controlled and saved throughout the reaches of the canal. The findings demonstrated the the west main canal of Dez has good potential to make savings, which can be realized at system level through reduced demand on supplemental from the dam.
Keywords: Performance assessment, Operation, Water delivery, Dez irrigation network, CANALMAN
Research Article
Sh. Jalili; S. Morid; A. Banakar; R. Namdar Ghanbari
Abstract
Abstract
The Urmia Lake as an important water body in the northwest of Iran, recently is faced with a critical level reduction, which makes it important to evaluate the causes. In this regard understanding of the Lake's behavior and assessing effect of tele-connections on lake level oscillations is ...
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Abstract
The Urmia Lake as an important water body in the northwest of Iran, recently is faced with a critical level reduction, which makes it important to evaluate the causes. In this regard understanding of the Lake's behavior and assessing effect of tele-connections on lake level oscillations is necessary. This subject constructs objective of the present paper that applies the spectral analysis techniques in which a combination of Multi Taper Method of spectral estimation and Singular Spectral Analysis were implemented to investigate harmonic periods of the Lake level. Also coherency analysis between lake level time series and SOI and NAO indices based on cross spectral estimation were done. The results showed that water level reduction of Lake Urmia in recent years and the increase of water level in 1994 to 1999 cannot be simulated by periodic behavior of Lake Urmia. But the 4.5 year oscillations of lake Urmia water level shows significant coherency with SOI and NAO indices and the effect of these climate forcing can explain periodic behavior of Lake Urmia to a high extent.
Keywords: Lake Urmia, Spectral estimation, Climatic indices, Coherency analysis
Research Article
F.S, Moosavi; F. Raiesi
Abstract
Abstract
Earthworms are an important component of soil fauna, and play a crucial role in the improvement of soil properties. However, very little is known of the interactive influence of earthworms and organic materials on soil enzyme activities, particularly in arid and semi-arid soils. The low organic ...
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Abstract
Earthworms are an important component of soil fauna, and play a crucial role in the improvement of soil properties. However, very little is known of the interactive influence of earthworms and organic materials on soil enzyme activities, particularly in arid and semi-arid soils. The low organic matter content and the significant role of earthworms in stimulating microbiological and biochemical properties of arid and semi-arid soils may justify researches on the interactive effects of organic materials and earthworms on soil enzymes. Thus, the main objective of this study was to identify the interactive effects of an anecic earthworm (Lumbricus terrestris L.) and various organic materials on soil urease, alkaline phosphatase, invertase, β-glucosidase and arylsulphatase activities. The experiment consisted of a 2×5 factorial treatment arranged in a completely randomized design with four replications under controlled greenhouse conditions. The first factor was soils inoculated with and without earthworm, and the second factor was soils amended with alfalfa, compost, cow dung, and a mixture of alfalfa and compost, in addition to a non-amended soil as the control. Potential soil enzyme activities were assayed 30, 60 and 90 days after the initiation of the experiment using the appropriate substrate for each enzyme under standard conditions. Results showed that the activities of most soil enzymes were markedly greater in the presence of earthworms than in the absence of earthworms. The addition of organic materials to soil also resulted in higher enzyme activities compared with the non-amended soils. Nevertheless, the simultaneous effect of earthworm inoculation and organic material additions was much more effective in increasing soil enzyme activities. Yet, the activities of soil enzymes showed fluctuations and varied during the experiment. We found that the averaged increase in soil enzyme activities over 60-90 days in treatments without earthworms was often more remarkable than in treatments with earthworms, indicating that earthworm activity may shorten the time period to attain the maximum enzyme activities (over 30-60 days).
Keywords: Soil enzymes, Earthworm activity, Organic materials, Arid and semi-arid soils
Research Article
L. Dayani; F. Raiesi
Abstract
Abstract
Cadmium is one of the heavy metals with a considerable importance for its potential toxic effects on soil microbial activities and composition. Although, the toxic effect of cadmium on soil microbial activities is somewhat well-known, but the extent to which Cd affects soil biota depends largely ...
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Abstract
Cadmium is one of the heavy metals with a considerable importance for its potential toxic effects on soil microbial activities and composition. Although, the toxic effect of cadmium on soil microbial activities is somewhat well-known, but the extent to which Cd affects soil biota depends largely on soil properties and conditions, particularly soil organic matter contents. Thus, the aim of this research was to study the effect of increasing cadmium levels on soil microbial biomass and activities, and to examine the role of compost materials in the alleviation of Cd effects. A 2×5 factorial experiment consisting of two levels of compost (0 and 2.5 t ha-1) and five levels of cadmium (0, 50, 100, 150 and 200 mg Cd kg-1) arranged in a completely randomized design with three replicates was carried out under laboratory conditions. The responses of soil microbiological properties consisting of C mineralization, microbial biomass C; and acid and alkaline phosphatase activities to cadmium and compost additions were evaluated during 10 weeks of laboratory soil incubation. Results show that cadmium additions had a significant, negative effect on all the measured microbiological properties. The accumulated C mineralization reduced with increasing cadmium concentrations. Nonetheless, compost addition lowered the detrimental and inhibiting effect of cadmium on soil microbial activities. Results demonstrate that in spite of a significant correlation (r=0.96) between the two Cd fractions, the added Cd at the beginning of soil incubation was not reflected totally in the total Cd concentrations determined at the end of soil incubation. Data also indicated that the fraction of available Cd had a stronger negative (cor)relation with soil microbial activities than the other fractions had. In summary, the results of the current study illustrate that even a lower concentration of Cd (50 mg kg-1) may inhibit soil microbial activities due to it toxicity in the studied soil, and that the addition of organic materials could be effective in reducing the toxicity of cadmium via lessening its bioavailability to soil biota.
Keywords: Cadmium, Soil microbial activity, Soil C dynamics, Compost, Soil enzymes
Research Article
A. Haghverdi; K. Mohammadi; S.A. Mohseni Movahed; B. Ghahraman; M. Afshar
Abstract
Abstract
Soil salinity within plant root zone is one of the most important problems that cause reduction in yield in agricultural lands. In this research, salinity in soil profile was simulated in Tabriz irrigation and drainage network using SaltMod and Artificial Neural Networks (ANNs) models. Based ...
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Abstract
Soil salinity within plant root zone is one of the most important problems that cause reduction in yield in agricultural lands. In this research, salinity in soil profile was simulated in Tabriz irrigation and drainage network using SaltMod and Artificial Neural Networks (ANNs) models. Based on initial spatial distribution of salinity in soil profile, studying area was divided to 4 different soil and water groups and for two seasons in one year salinity was predicted. The SaltMod model was calibrated and then was applied to generate 2400 data sets for training ANN models. Some of the input data of SaltMod were used in ANN models including irrigation water depth, evapotranspiration, water table depth, rainfall, and initial soil salinity. Efficiency of genetic algorithm in training phase of ANNs was analyzed. The mean of correlation coefficient (R2) and root mean square error (RMSE) of estimated salinity in all groups was 0.8 and 0.032 respectively. In conclusion ANNs could perform well in simulation of soil salinity and it could be replaced SaltMod with enough accuracy. The results showed that overall performance of ANN models improve by applying genetic algorithm.
Keywords: Tabriz plain, Soil profile salinity, Genetic Algorithm, Artificial Neural Networks, SaltMod
Research Article
B. Khalilimoghadam; M. Afyuni; A. Jalalian; K. Abbaspour; A.A. Dehghani
Abstract
Abstract
Surface soil shear strength is an effective parameter in soil erosion and runoff modeling, and known as soil erodibility index. This study was conducted to investigate and predict soil shear strength in central Zagros region using multiple linear regressions (MLR). The study site was selected ...
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Abstract
Surface soil shear strength is an effective parameter in soil erosion and runoff modeling, and known as soil erodibility index. This study was conducted to investigate and predict soil shear strength in central Zagros region using multiple linear regressions (MLR). The study site was selected in rangeland and degraded-rangeland landuse with an area of 23562 ha. Based on the maps of geology, topography, landuse and soil capability, 18 Land Unit Tracts (LUT) was created. Supervised random sampling was used to collect samples in every land unit. A total of 120 samples were collected in triplicates to determine sample variability in each LUT. Soil samples were collected from the 0-3 cm of soil depth. Routinely measured (available) parameters included particle size distribution, soil organic carbon, CaCO3 in addition to slope, aspect; elevation and normalized difference vegetation index (NDVI) were used. Three MLR models were tested and investigated for soil shear strength in this study. The performances of the different models were evaluated using spearman’s correlation coefficient (r) between the observed and the estimated values, normalized mean square error (NMSE), mean absolute error (MAE), geometric mean of error ratio (GMER) and geometric standard deviation of the error ratio (GSDER). Results showed that land degradation significantly reduced surface soil shear strength. Addition of slope, aspect, elevation and NDVI to soil attributes as input parameters improved the performance criteria for soil shear strength.
Keywords: Surface soil shear strength, Soil erodibility, Central Zgros
Research Article
A.R. Koocheki; M. Jahani; L. Tabrizi; A.A. Mohammadabadi
Abstract
Abstract
In order to investigate the effect of biofertilizer, chemical fertilizer and Plant Density on Yield and Corm Criteria of Saffron, an experiment was conducted as complete randomized block design in a factorial arrangement with three replications under field condition in agricultural college, ...
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Abstract
In order to investigate the effect of biofertilizer, chemical fertilizer and Plant Density on Yield and Corm Criteria of Saffron, an experiment was conducted as complete randomized block design in a factorial arrangement with three replications under field condition in agricultural college, Ferdowsi university of Mashhad during 3 years of 2007,2008,2009. treatments included Nitroxin biofertilizer ( a mixture of free-living nitrogen-fixing bacteria Azospirilum sp./ Azotobacter sp.), Dalfard fertilizer ( a commercialized saffron fertilizer with 12% N from Urea and nitrate sources, 8% P, 4%K and also Zn, Cu, Mg, Fe, Chelates) and control with five corm density 4, 6, 8, 10 and 12 t ha-1. Results indicated that effect of fertilizer treatment was significant on number of flower , dried and fresh flower weight, dried and fresh stigma weight during experimental year. Effect of fertilizer treatment was significant on number of corm, dried and fresh corm weight during second experimental year. The highest number of flower, dried flower weight, dried stigma weight and dried corm weight was shown in Dalfard and the lowest number of flower, dried flower weight, dried stigma weight and dried corm weight was obtain in Nitroxin. The effect of different densities was significant on number of flower, fresh flower weight, dried flower weight and dried stigma weight during second year. The highest dried stigma weight was obtained in 8 t ha-1 in second and third year. Regression results showed that with increasing the number of corm, dried corm weight was decreased.
Keywords: Nitroxin, Dalfard, Saffron
Research Article
M.S. Ghazanfari Moghadam; A. Alizadeh; M. Mousavi baygi; A.R. Farid-Hosseini; M. Bannayan Aval
Abstract
Abstract
Precipitation as the most important factor plays the main role in many application researches which are based on climatic parameters. Many researches in the field of hydrology, hydrometeorology and agriculture employs rain-gauges (such as synoptic and climatologic stations) data. Precipitation ...
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Abstract
Precipitation as the most important factor plays the main role in many application researches which are based on climatic parameters. Many researches in the field of hydrology, hydrometeorology and agriculture employs rain-gauges (such as synoptic and climatologic stations) data. Precipitation characteristics, such as rainfall intensity and duration, usually exhibit significant spatial variation, even within small watersheds; while rain gauge network density could not provide desirable cover. Nearly all related researches use interpolation methods for places without rain gauge data. Many studies showed that the estimated error was usually high by usual interpolation methods. Employing satellite data with high spatial and temporal resolution could provide accurate precipitation estimation. PERSIANN (Precipitation estimation from remotely sensed information using artificial neural network) model works based on the ANN (artificial Neural Network) system which uses multivariate nonlinear input-output relationship functions to fit local cloud top temperature (Tb) to pixel rain rates (R). In this study, PERSIANN model and two interpolation methods (Kriging & IDW) were employed to estimate precipitation for North-Khorasan between the years 2006 until 2008. Results show better correlation between PERSIANN outputs and station data than other two interpolation methods. while correlation coefficient for Kendal`s test is 0.805 between model and Bojnord Station data, this coefficient is 0.488 for IDW and 0.565 for Kriging methods.
Keywords: PERSIANN model, IDW, Kriging, Interpolation methods, Precipitation estimation
