Research Article
F. Mostashfi HabibAbadi; M. Shayannejad; M. Dehghani; S.H. Tabatabaei
Abstract
Abstract
The irrigation water quality is not suitable for crop production in most regions of Iran. It is estimated that almost six BCM/year of saline water enter to the rivers, in Iran. The saline water can potentially use for growing of tolerant crops with a specific management on the agriculture practice. ...
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Abstract
The irrigation water quality is not suitable for crop production in most regions of Iran. It is estimated that almost six BCM/year of saline water enter to the rivers, in Iran. The saline water can potentially use for growing of tolerant crops with a specific management on the agriculture practice. One of the management methods is the conjunction use of fresh and saline water. In this study, four conjunctive use of saline and fresh water is evaluated on yield and yield components of two sunflower cultivars. A split plot design was employed in completely randomize block form with eight treatments and four replication. The main level has two sunflower cultivars (Alestar and Haisan33) and in the sub main level, four irrigation regimes was exist (1- Irrigation with half saline water and then one half with fresh water, 2-Irrigation with half fresh water and then one more half with saline water, 3- Alternate irrigation with fresh and saline water 4-Conjunction irrigation). To prevent salt, the plots were irrigated with fresh water for the first three irrigation events. The treatments were applied up to the harvesting. The result shows that the saline- fresh irrigation regime had the highest yield index concerning oil, 100 seed's weight, seed yield, seed yield per capital, stem diameter, flower height, capital diameter, leaf area and leaf minerals. For Haisan33 cultivar the alternate regime and for the Alestar cultivar the conjunction regime was in the second grade.
Keywords: Saline water, Irrigation Management, Sunflower, Yield index
Research Article
N. Nikamal Larijani; A. Hassanoghli; M. Mashal; A.M. Liaghat
Abstract
Abstract
By increasing the world population and more need to supply food, farmers attend to use of chemical fertilizers, organic manures and pesticides. Also, applications of these agents without attention to their side effects, cause more problems to human health and environment. Nitrate is one of ...
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Abstract
By increasing the world population and more need to supply food, farmers attend to use of chemical fertilizers, organic manures and pesticides. Also, applications of these agents without attention to their side effects, cause more problems to human health and environment. Nitrate is one of the most important elements of organic manures, which leach through soil to surface and ground waters by irrigation or precipitation. So, it’s necessary to monitor the behavior of it. The purpose of this study was to determine the nitrate transport through two different soil textures, loam and silt loam via application of organic fertilizers. In this study, experiments were carried out by cylindrical drained plastic lysimeters with 100 cm height and 60 cm diameter, filled by uncondensed soil up to 60 cm height. Three different organic manures (poultry, cow and sewage sludge) were used on top soil of lysimeters by the rate of 35 tone/ha (upon the average use amounts of farmer's). 24 lysimeters were prepared; 9 lysimeters for 3 types of manure with 3 replicates and 3 without manure used as control for each soil type. The results were analyzed by a factorial experiment in a completely randomized form statistical design. Irrigation was done by one week intervals, totally three times with well water. Five drainage water samples (100 ml each sample) were taken through the first pore volume drained after irrigating of lysimeters. It means that each pore volume divided to 5 equal parts for sampling. The results showed that the nitrate concentration in loam soil was more than silt loam soil in drainage water samples, so it can be attributed to the effect of soil texture. Also for both soil textures, sewage sludge treatment was caused the most nitrate concentration, and the least was monitored in control treatment. The amounts of poultry and cow NO3 in drainage water samples were between them, respectively. Considering the one week irrigation intervals and three consecutive irrigations which were done, the amount of contamination in both soils in the first week was highest and in the third week was the lowest; it can be related to nitrate leaching by irrigations done.
Keywords: Water pollution, Nitrate leaching, Lysimeter, Organic manure
Research Article
E. Entezami; M. Shorafa; Gh.R. Savaghebi
Abstract
Abstract
Soil pollution with heavy metals like zinc causes increasing concerns about environment. According to distribution in soil, this study was conducted to compare zinc concentration between aggregate exteriors and interiors of some contaminated soils. Aggregates were collected from 5 depths of ...
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Abstract
Soil pollution with heavy metals like zinc causes increasing concerns about environment. According to distribution in soil, this study was conducted to compare zinc concentration between aggregate exteriors and interiors of some contaminated soils. Aggregates were collected from 5 depths of 4 soil profiles with different textures and were separated mechanically into exterior and interior fractions. Soluble and exchangeable and also bonded to carbonate fractions of zinc from both aggregate interiors and exteriors, were extracted and measured. The concentrations of zinc in both above fractions were high in the exterior part. Concentration of soluble and exchangeable zinc showed high correlation coefficient with soil pH and total concentration of soil zinc, also bonded to carbonate fraction of zinc showed high correlation coefficient with total concentration of zinc and low correlation coefficient with percentage of soil CaCO3.
Keywords: Aggregate, Contaminated soil, Forms of zinc
Research Article
S.S. Tabatabaee; A. Razazi; A. Khoshgoftar Manesh; N. Khodaeian; Z. Mehrabi; E. Asgari; Sh. Fathian; F. Ramezanzadeh
Abstract
Abstract
A hydroponics experiment was conducted to compare effect of Fe-deficiency on concentration, uptake, translocation of Fe, Zn, Mn in some plants. A completely randomized block design in triplicates was conducted in research greenhouse. Seven plants with different Fe-efficiency contained two bread ...
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Abstract
A hydroponics experiment was conducted to compare effect of Fe-deficiency on concentration, uptake, translocation of Fe, Zn, Mn in some plants. A completely randomized block design in triplicates was conducted in research greenhouse. Seven plants with different Fe-efficiency contained two bread wheat genotypes (Triticum aestivium L. CVs. Backcross Roshan and Qods), triticale (X. Triticosecale Cv eleanor), dent corn (Zea Mays L. CV. S.C704) and two safflower (Carthamus tinctorius L. CVs Arak2811 and Koose) were grown in a nutrient solution at two Fe levels of 5 and 50 µM Fe EDTA. The most tolerant and the most sensitive of plants to Fe-deficiency were bread wheat (Qods genotype) with 125% Fe-efficiency and safflower (Arak2811) with 3.5% Fe-efficiency, respectively. A significant and positive correlation was found between the Fe-efficiency and Zn, Fe and Mn contents and root to shoot translocation of Fe among the studied crops. Large variation was found among the studied crops in shoot and root Zn, Fe and Mn content. The Qods and cross back Roshan wheat genotypes accumulated greater Zn, Fe and Mn in their shoots compared to other genotypes. Higher uptake and root to shoot translocation of microelements in the Fe-efficiency genotypes is an important aspect for biofertilization programs with the aim of improving crop quality.
Keywords: Hydroponic Culture, Iron deficient, Fe-efficiency, Micronutrient, Uptake, Translocation of micronutrient
Research Article
Z. Farzanegan; Gh. Savaghebi; H. Mirseyed Hosseini
Abstract
Abstract
The use of plants to remove contaminants from the environment and concentrate them in above-ground plant tissue is known as phytoextraction. This study was conducted to investigate the potential of phytoextraction of Pb and Cd metals canola (Brassica napus) and sorghum (Sorghum bicolor) which ...
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Abstract
The use of plants to remove contaminants from the environment and concentrate them in above-ground plant tissue is known as phytoextraction. This study was conducted to investigate the potential of phytoextraction of Pb and Cd metals canola (Brassica napus) and sorghum (Sorghum bicolor) which are high Biomass Crop and the effect of amendments on the efficiency of phytoextraction. The soil sample for the experiment was collected from an area adjacent to a Zinc Concentrate factory in west of Zanjan, Iran. Five treatments compared included powdered sulfur, sulfur plus thiobaccilus inucolum (S+I) at 8g kg -1 rate, citric acid at two levels of 1g kg-1 (CA1) and 3g kg-1 (CA2) and the control (C). The experiment was conducted in two stages. In the first stage of study, the treated soil with the above material were incubated for 8 weeks at field capacity and 25˚C temperature. In the incubation period the subsamples were collected at 0, 4 and 8 weeks to determine the amount of plant available Pb and Cd using DTPA extraction. In the second stage, a greenhouse experiment was conducted using the same soil and treatments. Sorghum and canola were planted and grown for 60 days and then the above ground parts and roots were harvested. Plant samples were analyzed for Cd and Pb content and the amount of DTPA exractable Pb and Cd were measured in soils before and after planting. Both experiments were conducted in the factorial experiment with randomized complete design with 5 treatments (including control) and 4 replications. The statistical Analysis was done using SAS and MSTATC Softwares. The resulst indicated that effect of sulfur plus thiobaccilus and citric acid at 1g.kg-1 treatments on Cd and Pb availability were highest and lowest, respectively. The pot experiment showed that the best of amendment in transfer of metal from root to shoot for two plant species was powdered sulfur plus thiobaccilus inucolum. The results of greenhouse experiment indicated that canola has higher potential for remediation of Cd and Pb from contaminated soil in comparison with sorghum.
Keywords: Lead, Cadmium, Sorghum, Canola, Phytoextraction, Amendment
Research Article
M.R. Asgari; A.M. Liaghat; M. Parsinezhad
Abstract
Abstract
Although lateral drains play the main role in removal of excess water from soil profile in subsurface drainage systems, but it is assumed that perforated collectors can directly remove a part of drainwater from soils. This part of discharge in subsurface drains is not usually taken into consideration ...
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Abstract
Although lateral drains play the main role in removal of excess water from soil profile in subsurface drainage systems, but it is assumed that perforated collectors can directly remove a part of drainwater from soils. This part of discharge in subsurface drains is not usually taken into consideration in drainage design criteria, due to lack required information and its difficult estimation. If the level of collectors’ drain discharge is determined, drainage coefficient for laterals can be adjusted depending. Consequently the distance between laterals is increased and economic value of drainage system design is more justified. This research was conducted in drainage network of Amirkabir Agro-Industrial Unit with the purpose of determining collectors’ discharge level and lateral’s drainage coefficient adjustment. Therefore, measurement of water table, discharge of laterals and collectors in ARC2-14 farm having 25 hectare size was measured. Results obtained from field measurements indicate collectors directly discharge approximately 2.8 litter water per second or 2 mm per day or about 24% of total drainage discharge within the system. The actual drainage coefficient will then be reduced from 8.24 to 6.24 mm/day. This change will result an increase in lateral distance from 40 to 44 m.
Keywords: Drainage coefficient modification, Collector or collecting drainage, Constant flow
Research Article
E. Amiri; M. Rezaei; M. Bannayan Awal
Abstract
Abstract
To evaluated ORYZA2000 model in Iran, this study was carried out during 2004 till 2007 at Rice Research Institute of Iran, Rasht. The experiment was conducted as split plot in complete randomized block design and three replicates. Three irrigation levels were the main plots and four levels ...
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Abstract
To evaluated ORYZA2000 model in Iran, this study was carried out during 2004 till 2007 at Rice Research Institute of Iran, Rasht. The experiment was conducted as split plot in complete randomized block design and three replicates. Three irrigation levels were the main plots and four levels of N application were allocated sup-plots model. Simulated and measured values leaf area index (LAI) and biomass of leaves, panicles, total aboveground biomass and crop N dynamics, was evaluated by adjusted coefficient of correlation; t-test of means; and absolute and normalized root mean square errors (RMSE). Results show that, with normalized root mean square errors (RMSEn) of 5–51%, ORYZA2000 satisfactorily simulated crop biomass and N uptake that strongly varied between irrigation and nitrogen fertilizer. Yield was simulated with an RMSE of 155–464 kg ha-1 and a normalized RMSE of 3–11%. Simulated LAI generally exceeded measured at low rates of nitrogen application. Results show that, ORYZA2000 could be used successfully to support N and irrigation management under the limited conditions.
Keywords: Rice, Model, Evaluation, Nitrogen, Irrigation
Research Article
Sh. Moslehi; P. Najafi; S.H. Tabatabaei; N. Nourmahnad
Abstract
Abstract
Soil moisture measurement and control is a base to employ optimal management methods for reducing water consumption and improvement of the product quality. The main objective of this research was increasing the efficiency of water consumption in a greenhouse condition. This study was carried ...
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Abstract
Soil moisture measurement and control is a base to employ optimal management methods for reducing water consumption and improvement of the product quality. The main objective of this research was increasing the efficiency of water consumption in a greenhouse condition. This study was carried out in the framework of three treatments of soil potential including irrigation at 40, 60 and 80 c-bar tension with three replications. The cultivated plant was the greenhouse cucumber and the growth indexes included fruit weight, fruit diameter, fruit size, stem diameter and Leaf Area Index (LAI) measured by scale, calliper and planimeter, respectively. Six plants were selected randomly from each replication in each treatment. The LAI was calculated in three small, medium and large sizes. Statistical analysis showed that treatments 40 and 60 c-bar have led to a significant yield increase (p
Research Article
N. Majidi; A. Alizadeh; M. Ghorbani
Abstract
Abstract
In refrence to un appropriate time and place dispersal of precipitation in Iran and having low efficiency in agriculture, water as the most limitative factor in agriculture is discussing. In this study, the existing pattern of Mashhad-CHenaran plain is considering and with gathering data related ...
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Abstract
In refrence to un appropriate time and place dispersal of precipitation in Iran and having low efficiency in agriculture, water as the most limitative factor in agriculture is discussing. In this study, the existing pattern of Mashhad-CHenaran plain is considering and with gathering data related to 1388, with target of decrease in water consuming, optimum and nearly optimum cropping pattern was determined. In order to reach to this target, we used linear programming and modeling to generate alternatives. Related result which were reached from linear programming showed that use of all under cropping area and also reaching gross margin like existing pattern, the amount of water consuming had been decreased which is resulted from new compound of yields in production system. Also in the optimal state surface of products such as sugar beet, beans and sunflower due to high water consumption and having lower gross margin were removed from the cropping pattern. Also nearly optimum pattern showed that even an increase of 5% and 7% in amount of consuming water rather than optimum position, only at most 1.5% gross margin had been increased, that because of importance using continuous of water resource and protection of this worthful resource, so extra utilization doesn’t recommend. In refrence to result, using making optimum patterns in codifying cropping pattern in plain are recommended.
Keywords: Optimal Cropping Pattern, Water Resources Management, Lineare programming, Nearly optimal programming
Research Article
M.H. Davoodi; R. Rahnemaie; M.J. Malakouti
Abstract
Abstract
Phosphate is an essential element for plants, animals, and human. Mobility and availability of phosphate in the natural systems is controlled by the adsorption-desorption and dissolution-precipitation reactions. Iron (hydr)oxides including goethite play an important role in phosphate adsorption ...
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Abstract
Phosphate is an essential element for plants, animals, and human. Mobility and availability of phosphate in the natural systems is controlled by the adsorption-desorption and dissolution-precipitation reactions. Iron (hydr)oxides including goethite play an important role in phosphate adsorption reactions in soil. Surface area, crystallinity, and morphology of iron (hydr)oxides are the most important characteristics influencing phosphorus adsorption capacity. With respect to the importance of adsorption process in controlling equilibrium concentration of phosphate in soil and other natural systems, in this research phosphate adsorption reactions on goethite was investigated on three samples of goethite differed in surface area over a wide range of pH and initial phosphate concentration. The goethite charging behavior was calculated from acid-base titration in different levels of ionic strength. The experimental data were analyzed with the CD-MUSIC surface complexation model. Titration data revealed pHpzc= 9.1. Experimental data revealed that phosphate adsorption is strongly pH-dependent. Maximum phosphate adsorption was measured at low pH. It was gradually decreased with increasing pH. Adsorption data were successfully described using two inner-sphere surface complexes, i.e . and . The calculated CD values indicated that 0.28 and 0.46 vu charge is transferred to the goethite surface due to the adsorption of and , respectively. Mole fraction calculation showed that and are the dominant surface species at low and high pH, respectively. Furthermore, experimental data and model calculations revealed that surface area influence phosphate adsorption considerably; however the change in the surface area has no measurable effect on the goethite site density. Therefore, the entire experimental data were successfully predicted by using one set of adsorption parameters.
Keywords: Adsorption, Phosphate, Goethite, CD-MUSIC model, Charging behavior
Research Article
D. Rezaei; Gh. Haghnia; A Lakziyan; M. Hassanzadeh Khayyat; H. Nasirly
Abstract
Abstract
Atrazine biodegradation by bacteria is one of the most important aspects of bioremediation. Atrazine can be degraded by various species of bacteria. Bacteria use atrazine as nitrogen and carbon sources. The aim of this study was to determine atrazine degradation by Pseudomonas fluorescence ...
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Abstract
Atrazine biodegradation by bacteria is one of the most important aspects of bioremediation. Atrazine can be degraded by various species of bacteria. Bacteria use atrazine as nitrogen and carbon sources. The aim of this study was to determine atrazine degradation by Pseudomonas fluorescence and Pseudomonas aeruginosa. The experiment consisted of two Pseudomonas bacteria, three levels of atrazine concentrations (100, 200 and 300 mg.l-1) and four types of MSM medium (complete, without nitrogen, without carbon and without nitrogen and carbon source). The results showed that both bacteria were able to degrad atrazine at all concentrations. However, increasing atrazine concentration led to more degradation of this herbicide. Biodegradation of atrazine by Pseudomonas fluorescence in concentrations of 100, 200 and 300 mg.l-1 was 18.5, 48.91 and 72.6% respectively and it was 19.08, 33.83 and 62.66% respectively for Pseudomonas aeruginosa in a period of 48 hr. The most degradation of herbicide was observed by Pseudomonas fluorescence in MSM medium without N treatment. In this study nitrogen source was a limiting factor in degradation of atrazine by Pseudomonas fluorescent. Nitrogen source had no significant effect on degradation of atrazine by Pseudomonas aeruginosa in comparison with other MSM medium. In addition, the carbon source in both conditions (with and without) had no significant effect on atrazine degradation by both bacteria.
Keywords: Atrazine, Biodegradation, Pseudomonas aeruginosa, Pseudomonas fluorescence
Research Article
M. Shariaty; Gh. Sayyad; A. Barzegar; Z. Darvishpasand
Abstract
Abstract
Disc infiltrometer is one of those devices that used in recent years in measurement of hydraulic conductivity of entire soil. In order to analyze the data taken by Disc infiltrometer a variety of methods based on Wooding’s base analyze have been introduced. The objective of this study was ...
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Abstract
Disc infiltrometer is one of those devices that used in recent years in measurement of hydraulic conductivity of entire soil. In order to analyze the data taken by Disc infiltrometer a variety of methods based on Wooding’s base analyze have been introduced. The objective of this study was to compare the performances of Ankeny and Weir methods for predicting soil hydraulic properties using disc data. The study was conducted using a 10 cm radius disc infiltrometer in three different soil texture. The water infiltration was measured for silty loam soil using 15, 10, 7, 3, 1 cm tensions, for loamy sand using 10, 7, 5, 3, 1 cm tensions, and for sandy soil using 30, 25, 21, 17 cm tensions, respectively. The average calculated sorptive number was 0.065, 0.175, and 0.192 cm-1 for loamy sand, sandy, and silty loam soils, respectively. All the unsaturated- saturated hydraulic conductivity coefficients obtained for three soil textures using Ankeny analyze were bigger than the values obtained using modified Weir equation so that the predicted saturated hydraulic conductivity coefficients using Ankeny analyze for sandy loam soil 7.5%, for silty loam soil 29%, and for sandy soil 45% were greated than Weir estimates.
Keywords: Equations Ankeny, Equations Weir, Unsaturated and Saturated Hhydraulic Conductivity,
Disc infiltrometer
Research Article
M. Karimi Amirkiasar; M. Ardalan; M. Kavoosi; H. Shokri Vahed
Abstract
Abstract
The increasing of yield per unit area is usually achievable by improving the soil fertility level through using (chemical) fertilizers. The purpose of the present research was to evaluate the 6 extraction methods including Olsen, Morgan, Ammonium bicarbonate-DTPA, Colwel, Bray and Mehlich ...
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Abstract
The increasing of yield per unit area is usually achievable by improving the soil fertility level through using (chemical) fertilizers. The purpose of the present research was to evaluate the 6 extraction methods including Olsen, Morgan, Ammonium bicarbonate-DTPA, Colwel, Bray and Mehlich 3 in order to specify a suitable extractant(s) for estimating available phosphorus through using 27 paddy field soils in Guilan province. For farm evaluation, two fertilizer treatments of 0 and 60 kg ha-1 of Triple Super Phosphate in Phosphorus pentaoxide were used. the correlation coefficients between extracted phosphorus by different extractants and relative yields, phosphorus concentration and phosphorus uptake by rice shoots indicated that Colwell, Olsen and Bicarbonate ammonium-DTPA extraction methods had an acceptable correlation with relative grain yield, phosphorus uptake and phosphorous concentration. Thus, with consideration of economic and applicability aspects, extraction speed and its acceptable relationship with plant indices, Olsen extraction method is recommended for available phosphorus.
Keywords: Correlation, Extractants, Phosphorus, Rice
Research Article
A.A. Sabziparvar; M. Shadmani
Abstract
Abstract
In this research, temporal trends of reference evapotranspiration (ET0) values were investigated in arid regions of Iran. For this purpose, the meteorological observations collected from 11 high quality meteorological sites for a 41-year period (1965-2005) were used and statistically significant ...
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Abstract
In this research, temporal trends of reference evapotranspiration (ET0) values were investigated in arid regions of Iran. For this purpose, the meteorological observations collected from 11 high quality meteorological sites for a 41-year period (1965-2005) were used and statistically significant ET0 trends in the monthly, seasonal and annual time basis were detected by the non-parametric Mann-Kendall and Spearman tests at confidence level of 95 %. For eliminating the effect of serial correlation on test results, the Trend Free Pre-Whitening (TFPW) approach was applied. The results indicated that the ET0 trends for some sites were increasing (positive) but for some sites showed decreasing (negative) trends. The most significant ET0 trends on the monthly time scale occurred at Birjand but no significant trend was observed for Bandarabbas, Sabzevar and Semnan sites. On the annual time scale, Mashhad revealed the highest positive ET0 trend (7.5 mm per year). On the contrary, Esfahan showed the highest decreasing (negative) ET0 trend of about -6.38 mm per year. In general, the performances and capabilities of Mann-Kendall and Spearman tests were consistence at the verified confidence level.
Keywords: Trend, Reference evapotranspiration, Mann-Kendall test, Spearman test
Research Article
M. Akbari; Z. Seif; H. Zare Abyane
Abstract
Abstract
Evapotranspiration (ET) is one of the most important components of the water balance, it is also one of the most difficult to measure. Despite the importance of ET, methods to obtain values of ET are still limited. Conventional methods are very local, ranging from point to field scale. Estimates ...
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Abstract
Evapotranspiration (ET) is one of the most important components of the water balance, it is also one of the most difficult to measure. Despite the importance of ET, methods to obtain values of ET are still limited. Conventional methods are very local, ranging from point to field scale. Estimates of the ET over the entire area, especially for irrigated areas, are essential, as these can differ substantially depending on the crop and the management applied. Today, actual and potential evapotranspiration under different conditions can be estimated by using satellites and remote sensing (RS) techniques. So that in this research, recent twenty years metrological data was assessed and based on precipitation, temperature and wind speed, three period include drought, normal and wet years (2000, 1995 and 2007 respectively) was chosen. The actual and potential evapotranspiration was estimated from a time series of NOAA-AVHRR satellite images using the SEBAL (Surface Energy Balance Algorithm for Land) algorithm in Abshar irrigation system in Esfahan during the three selected years. The results show that the maximum evapotranspiration (8.1 mm/day for ETa and 9.5mm/day for ETp) occurs in 2000 as a drought year. Comparing the potential evapotranspiration results of SEBAL method with Hargreaves and FAO-56 Penman-monteith methods show that, SEBAL method and conventional methods has the same results under current condition, so remote sensing techniques can estimated actual evapotranspiration and produce high spatial coverage of important terms in the water balance for large areas, but at the cost of a rather sparse temporal resolution. As water is highly manageable in irrigation systems, it is an application typically suitable to establish improvements in irrigation water management at large scale such as basin and irrigation systems.
Keywords: Evapotranspiration, Remote sensing, Water management, Abshar irrigation system
Research Article
A. Aazami; K. Zarafshani; H. Dehghanisanij; A. Gorji
Abstract
Abstract
The main purpose of this study was to determine farmers’ satisfaction towards pressurized irrigation systems in Kermanshah province. This study used a mixed method design with descriptive correlation emphasis. A researcher made questionnaire was used to collect data. A random sample of 274 ...
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Abstract
The main purpose of this study was to determine farmers’ satisfaction towards pressurized irrigation systems in Kermanshah province. This study used a mixed method design with descriptive correlation emphasis. A researcher made questionnaire was used to collect data. A random sample of 274 farmers who have been equipped with pressurized irrigation systems during the last three years participated in the study. Results revealed that 77% of those farmers were satisfied with their systems whereas 23% were unsatisfied. Moreover, there was same level of satisfaction between drip and sprinkler irrigated farmers. Level of satisfaction across farmers with different sprinkler systems showed that farmers using non-portable sprinkler systems were most satisfied. Water resources also influenced farmers’ satisfaction. Those utilizing wells and khanat were more satisfied than farmers using other water resources. In addition, land owners were more satisfied than landless farmers equipped with pressurized irrigation systems. Furthermore, farmers were most satisfied with: increased yield, higher quality product, less dependence on farm workers, water use efficiency, even water distribution, and increased irrigated farms. However, farmers were least satisfied with: low quality spare parts, incompetent sprinkler designers, administrative obstacles in receiving loans, and non-adaptability of systems in different climatic conditions. The results of this study has implications for pressurized irrigation policy-makers in that they can use predictors of satisfaction in identifying weaknesses and strengths of pressurized irrigation systems when designing development strategies.
Keywords: Sprinkler irrigation, Drip irrigation, Farmer users, Satisfaction
Research Article
M. Asgari; M.R. Mobasheri; M. Taleai; M. Ghamary Asl; Y. Rezaei
Abstract
Abstract
The amount of needed fertilizer in agricultural soils depends to the type of crop. Absence of enough fertilizer may cause in tensions in plants and consequently result in decrease in amount of product. According to the agricultural literature, soils containing total nitrogen amounts (N %) between ...
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Abstract
The amount of needed fertilizer in agricultural soils depends to the type of crop. Absence of enough fertilizer may cause in tensions in plants and consequently result in decrease in amount of product. According to the agricultural literature, soils containing total nitrogen amounts (N %) between 0.1-0.15 percent are considered as soils containing normal amounts of nitrogen. The values greater than 0.15% indicate rich amounts of nitrogen in soils. Accurate and timely information in this respect can be effective in increasing agriculture land gain. Applying experts and laboratories for measuring the amount of fertilizer can be time consuming and expensive. Remote Sensing technology, performing based on spectral behavior, sometimes produces acceptable data in large scale. To this end, spectral behavior of added material and agricultural soils should be used. In this study some data have been simulated by using a. spectral behavior of embedded nitrogen in soils containing nitrogen such as: Ammonium Nitrate (26% nitrogen), and Ammonium Sulfate (21% nitrogen), and b. spectrum of suitable soils for agriculture such as Sandy Loam soil between 1000 to 2500 nm. Then a regression model was produced and used. Evaluation of model shows the more than 80% correlation between real amount of materials in soil and measured amount which in present condition is valuable. In this paper infinities also were discussed and considered.
Keywords: Hyperspectral, Remote Sensing, Agriculture, Nitrogenized Fertilizer
Research Article
F. Raiesi; F. Aghababaei
Abstract
Abstract
Soil microbial activity and biochemical processes are often limited by carbon availability in arid- and semi-arid regions, probably due to the low organic matter content. Consequently, return of plant residues to soil is a convenient and effortless practice for increasing microbial activities ...
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Abstract
Soil microbial activity and biochemical processes are often limited by carbon availability in arid- and semi-arid regions, probably due to the low organic matter content. Consequently, return of plant residues to soil is a convenient and effortless practice for increasing microbial activities and biochemical reactions. The primary objective of this study was to evaluate the effect of various plant residues on soil microbial respiration and biomass, and enzymatic activities as well. The experiment consisted of a completely randomized design (CRD) with three replications under laboratory conditions. Experimental treatments consisted of seven plant residues including wheat, alfalfa, corn, rice, almond, walnut and grape, common in agro-ecosystems of Chaharmahal va Bakhtiari province, with a control soil without plant residue addition. Results show that the added plant residues brought about a significant increase in microbial activity (soil respiration) and biomass with concurrent increases in enzyme activities in the studied soil. The results of the current study indicate that enzyme activities would alter with changes in substrate quality during the course of plant residue decomposition. However, the extent to which, soil microbial activity and biomass, and enzyme activities fluctuate depended largely upon the type and quality of plant residues used, and the stage of residue decomposition.
Keywords: Litter chemical composition, Soil respiration, Soil Microbial biomass, Soil Enzyme Activities, Cropping systems
Research Article
Y. Ramezani; M. Ghomeshi
Abstract
Abstract
Turbidity current is one of the most important factors that effect the sediments distribution and also their transportation and release from reservoir. In this study, effects of these currents on sedimentation process in Sefidroud dam were simulated by TCM model in 30 years period. Comparison ...
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Abstract
Turbidity current is one of the most important factors that effect the sediments distribution and also their transportation and release from reservoir. In this study, effects of these currents on sedimentation process in Sefidroud dam were simulated by TCM model in 30 years period. Comparison between the case of turbidity currents that reach to the dam wall and release from the reservoir, and the case of neglecting the effects of these currents (all sediments deposit approximately) were conducted. The results show that in the case of releasing the turbidity currents from the reservoir, the trap efficiency of Ghazalozan branch would decrease about 30 percent in comparison with the other case. Also, this reduction would be about 20 percent in Shahroud branch. Comparison between the two cases of operations show that the average of annual volume reduction of the Ghazalozan branch would decrease from 1.07 to 0.73 and 0.55 to 0.43 in Shahroud branch, if Turbidity currents release from the reservoir.
Keywords: Reservoir Sedimentation, Turbidity Current, Trap Efficiency, Sefidroud Dam, TCM Model
Research Article
H. Shohab Arkhazloo; H. Emami; Gh. Haghnia; A.R. Karimi
Abstract
Abstract
Soil quality is an essential concept for maximum agriculture production without environmental destruction. Studying soil physical quality indicators, that express soil structural stability and soil air-water balance in root zone, is one of the most important aspects of soil quality. So determination ...
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Abstract
Soil quality is an essential concept for maximum agriculture production without environmental destruction. Studying soil physical quality indicators, that express soil structural stability and soil air-water balance in root zone, is one of the most important aspects of soil quality. So determination of optimal range for pore volume distribution is important and this research carried out to determine i) the optimal range for pore volume distribution according to soil physical quality indicators ii) the effect of soil properties on the slope of retention curve at its inflection point or Sgi index and iii) the effect of type of land use on soil physical quality indicators. The classification of studied soils was Haplocalcid, soil texture varied from sand to clay loam and organic carbon (OC) also changed between 0.2 to 2.2 percentages. In this study, Sgi index and pore volume distribution were determined by fitting the experimental soil retention curve data of 40 soil samples to van Genuchten equation in agricultural and rangeland land uses in south of Mashhad plain. Also some other soil physical quality indicators such as, percentage of organic carbon, bilk density, sodium absorption ratio (SAR), mean weight diameter of wet aggregates (MWD), relative field capacity (RFC), plant available water capacity (PAWC), air capacity (AC), and structural stability index (SI) were measured. Then the optimal range of pore volume distribution was determined by using of 8 soil physical quality indicators. Also the correlation between Sgi index and soil physical properties was determined. The positive and significant correlation between Sgi index and percentage of %OC, mean MWD, RFC, and PAWC was shown. But there was a negative and significant correlation between Sgi index and SAR in both land uses. In addition, mean comparison of indicators in two land uses showed that, among the 8 indicators, Sgi index, MWD, PAWC has been decreased significantly in agriculture land use samples.
Keywords: Pore volume distribution, Sgi Index, Soil physical quality
Research Article
S. Koozehgaran; M. Mousavi Baygi; S.H. Sanaei-Nejad; M.A. Behdani
Abstract
Abstract
Knowledge of the coordination of the agricultural activities in every region with the weather and climate condition of that area is necessary for any kind of agriculture activity. Therefore, understanding the climate and analyzing the ecophysiological characteristics of plants are the most ...
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Abstract
Knowledge of the coordination of the agricultural activities in every region with the weather and climate condition of that area is necessary for any kind of agriculture activity. Therefore, understanding the climate and analyzing the ecophysiological characteristics of plants are the most important factors in production. Saffron is one of the most valuable plants, which is planted in special climate conditions and has a unique growth process. At the present, Iran produces of 90% of total saffron production. Despite its old culture compared to other crops produced in the country, production of saffron in Iran that has relied primarily on indigenous knowledge. Analysis of the effect of the weather parameters on the performance of saffron and determining the suitable areas for planting saffron according to these parameters are important for agriculture and the economy. The statistics and data of 20 years taken from all the weather station in the region and the ten years performance of saffron were used in this study. Regression analysis and create of equation using minimum, average, maximum temperature and the relation between these parameters by saffron yield were accomplished by the use of JMP4 software. The digital climate maps of zoning scheme using software ArcGIS9.2 were drawn. The results showed that minimum temperature was the most effective factor on the performance during the month of Mehr, Aban, Azar and Dey compared with the other months and considering average temperature, the most affected months are Mehr, Aban, Azar and Dey. Maximum temperature was most effective on the performance during the month of Aban, Azar, Dey and Esfand compared with the other months Also after analyzing the equation and the climate zonation maps and the final map it become obvious that the most of the areas of the province were able to be ranked as suitable. The north and north-eastern areas were the best areas regarding the parameters discussed in order to grow Saffron. The center of province was considered average region to grow Saffron and the southern and south-western areas were determined the least suitable for growing saffron.
Keywords: Minimum, Average, Maximum temperature, Saffron yield, GIS
Research Article
Z. Aghashariatmadary; M.A. Khalili; P. Irannejad; A.M. Liaghat
Abstract
Abstract
Angstrom-Prescott equation is one of the most commonly used methods for the estimation of global solar radiation (Rs) based on sunshine hours. The critical step in the application of this method's is the calibration of its coefficients for each region. Although the coefficients of the equation ...
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Abstract
Angstrom-Prescott equation is one of the most commonly used methods for the estimation of global solar radiation (Rs) based on sunshine hours. The critical step in the application of this method's is the calibration of its coefficients for each region. Although the coefficients of the equation have been calibrated in different parts of the World, the effect of different time scales has not been considered clearly. In this article, variations of the coefficients of A-P equation in different time scales and their effects on the estimation of global solar radiation are studied. For this purpose data for the 15-year period of 1992-2006 from the Tehran-North (Aghdasieh) station in daily and monthly time scales are used. The values of the coefficients derived from the daily and monthly data were clearly different, and the equation based on monthly data has higher coefficient of determination (R2=0.92) compared to that based on the daily data (R2=0.48). We also found that the daily total solar radiation incident at the surface can be estimated well by using the A-P equation derived based on monthly data.
Keywords: Calibration of Angstrom-Prescott equation, Global solar radiation estimation, North of Tehran station, Time scales
Research Article
N. Sayari; A. Alizadeh; M. Bannayan Awal; A.R. Farid Hossaini; M.R. Hessami Kermani
Abstract
Abstract
The climate change was known to force local hydrology, through changes in the pattern of precipitation, temperature and the other hydrological variables. In this research, the impact of global warming on maximum and minimum temperature, precipitation and evapotranspiration (wheat, corn, tomato ...
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Abstract
The climate change was known to force local hydrology, through changes in the pattern of precipitation, temperature and the other hydrological variables. In this research, the impact of global warming on maximum and minimum temperature, precipitation and evapotranspiration (wheat, corn, tomato and sugar beet) of Kashafrood basin under two climate change scenarios (A2 and B2), and the output of two GCM models (HadCM3 and CGCM2) for three period of times (2010-2039, 2040-2069 and 2070-2099), were investigated. For evaluation two scenarios were downscaled into local level with Automated Statistical Downscaling (ASD) model. Precipitation was expected to decrease and/or increase, depends on applied GCM. The results indicated that the annual precipitation decreased for three periods under CGCM2 model and also for two scenarios (A2 and B2) as much as 13%-16% decreasing, the annual precipitation for three periods under HadCM3 model and two scenarios (A2 and B2) as much as 2%-8% increasing. The maximum and minimum temperatures in the Kashafrood basin was predicted, which increased by CGCM2 and HadCM3 models with two scenarios. Based on the HadCM3 model, maximum and minimum temperatures were expected to increase 2.4 0C to 5.8 0C and 0.6 0C to 3.8 0C, respectively; for 2070-2099 periods. For CGCM2 model, maximum and minimum temperatures were expected to increase 0.06 0C to 2.59 0C and 0.1 0C to 1.9 0C respectively; for 2070-2099. Evapotranspiration under A2 and B2 scenarios and HadCM3 model was increased but increasing in evapotranspiration with CGCM2 model under both scenarios was not significant in many cases. The comparison of two models and also two scenarios indicated that more critical status for A2 scenario by using two GCM models for this basin.
Keywords: Climate change, General circulation model, Downscaling, HadCM3, CGCM2, Kashaf rood basin, Evapotranspiration
Research Article
A. Lashkari; A. Alizadeh; M. Bannayan Awal
Abstract
Abstract
Development and evaluation of mitigation strategies are very crucial to manage climate change risk. Research objectives of this study were (1) to quantify the response of maize grain yield to potential impacts of climate change and (2) to investigate the effectiveness of changing sowing date ...
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Abstract
Development and evaluation of mitigation strategies are very crucial to manage climate change risk. Research objectives of this study were (1) to quantify the response of maize grain yield to potential impacts of climate change and (2) to investigate the effectiveness of changing sowing date of maize as a mitigation option for Khorasan Province which is located in northeast of Iran. Two type of General Circulation Models (HadCM3 and IPCM4) and three scenarios (A1B, A2 and B1) at four locations (Mashhad, Birjand, Bojnourd and Sabzevar) employed in this study. Statistical downscaling method was applied for developing quantitative relationship between large scale atmospheric variables (predictors) and local variables (observes), and generating daily climatological variables performed by LARS-WG stochastic weather generator. The CSM-CERES-Maize model was used to achieve study objectives. The result showed that the simulated grain yields of maize gradually would decrease (ranged from -1% to -39%) during future 100 years compared to baseline under different scenarios and two GCM at all study locations. In general, Bojnourd experienced the highest simulated grain yields of maize under A1B scenario (12234 Kg/ha), A2 scenario (12662 Kg/ha) and B1 scenario (12653 Kg/ha) during the period of 2010-2039 by planting date of 19 June. Sabzevar experienced the lowest simulated grain yields of maize under A1B scenario (3320 Kg/ha), A2 scenario (2370 Kg/ha) and B1 scenario (3582 Kg/ha) during the period of 2070-2099 by planting date of 4 June. Delayed sowing of maize crop (from May to June) at all locations, except for Sabzevar is the most effective management factor in mitigating the thermal detrimental effects.
Keywords: Climate change scenarios, Crop growth simulation, General Circulation Model, Maize yield
Research Article
B. Ashraf; M. Mousavi Baygi; G.A. Kamali; K. Davari
Abstract
Abstract
Due to low spatial resolution or simplifying of some micrometeorological phenomena, atmospheric general circulation models are not able to give a good estimation for weather conditions over study area. So their outputs should downscale into weather stations scales. In this research data of ...
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Abstract
Due to low spatial resolution or simplifying of some micrometeorological phenomena, atmospheric general circulation models are not able to give a good estimation for weather conditions over study area. So their outputs should downscale into weather stations scales. In this research data of HADCM3 downscaled by using LARS-WG5 with three scenarios, confirmed by IPCC including A1B, A2 and B1 and seasonal variations of precipitation, min temperature, max temperature and sunshine hours of Khorasan Razavi province were investigated over 2011- 2030. Results show that the amount of precipitation in all stations will increase in autumn, winter and spring except Torbat-jam. Also the amount of precipitation in Kashmar during the autumn will decrease. The maximum and minimum increases in precipitation are belonging to Ghoochan and Sarakhs respectively. The results also show that the minimum temperature in all seasons and under three scenarios indicate rising trend in most cities. The only exception in this case occurred in autumn for Sarakhs based on A1B scenario. About maximum temperature and sunshine hours, although three scenario would not explain the same pattern, but generally in the next 20 years, the maximum temperature of Khorasan Razavi province, will increase and sunshine hours will decrease. Also despite the variation of maximum temperature is less than minimum temperature, is expected increase of average air temperature in this period. So according to these results, climatic conditions of Khorasan Razavi province in the next 20 years will have noticeable different with the present conditions and seems necessary, long-term and strategic planning to manage this situation.
Keywords: Climate change, Downscaling, General circulation model, LARS-WG5 model
