Research Article
M.R. Nori Emamzadeie; A. Rahmati; B. Ghorbani; A.R. Mohammadkhani
Abstract
Abstract
Aeration is conducted on the perennial grasses such as lawns to reduce soil compaction and enhances the growth as well as improves soil infiltration. In order to evaluate the effects of aeration and topdressing on water infiltration phenomenon in a perennial lawn a factorial experiment in a ...
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Abstract
Aeration is conducted on the perennial grasses such as lawns to reduce soil compaction and enhances the growth as well as improves soil infiltration. In order to evaluate the effects of aeration and topdressing on water infiltration phenomenon in a perennial lawn a factorial experiment in a completely randomized design was conducted in the city of Isfahan in June 2009. Aeration, as the main experimental factor, consists of three levels, A0 (without aeration), A1 and A2 (with punching 1 cm diameter holes on the surface in a regular grid pattern and dimensions of 5×5 and 10×5 cm, respectively) and mulching, as the second experiment factor, consists of two levels, T0 and T1 (with and without any cover), were used for this purpose. To find the effects of the treatments on infiltration phenomena, infiltration was measured using Double Ring Method at three periodic times, i.e., 10, 70 and 130 days and data were analyzed ultimately using SAS software. The drawn results showed that applying A2T1 treatment, compared with A0T0 treatment as a control, increased cumulative infiltration by 286 percent and improved the final infiltration rate from 0.4 to 1 cm/h. On the other hand, A1T1 and A2T1 treatments application had no significant effect on the infiltration, but the effects of both treatments were significantly different from control, A0T0. On this basis, applying A2T1 treatment compared with A1T1 is technically and economically preferred, because of low Ip index. On overall, aeration improves soil permeability and its effects last by topdressing materials. By the way, aeration without topdressing is recommended for the lawn in flood prone areas.
Keywords: Aeration, Basic Infiltration Rate, Cumulative Infiltration, Loliumgrass, Topdressing
Research Article
S.A. Mousavi; E. Amiri Tokaladany; M.H. Davoudi
Abstract
Abstract
Rockfill dams are a type of hydraulic control structures used to protect river bed in cases where a considerable reservoir volume is available behind these structures; it could mitigate the floods and provide a gradual depletion of incoming volume of water so that the discharge passing downstream ...
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Abstract
Rockfill dams are a type of hydraulic control structures used to protect river bed in cases where a considerable reservoir volume is available behind these structures; it could mitigate the floods and provide a gradual depletion of incoming volume of water so that the discharge passing downstream is decreased. One of the main issues on utilizing rockfill dams is to keep its permeability enough so that it could be able to pass the flow as well as the sediment load through its body during flooding, avoiding sediments resettlement inside the pores. In this regard, the design of rockfill dams should be carried out so that the available hydraulic gradient is always kept greater than the critical hydraulic gradient, which consequently results in transporting the sediment through the dam body. In this research, a relationship to estimate the critical hydraulic gradient to transport noncohesive sediment through rockfill dam body is introduced. We tested the new equation using a set of published data. Also, using laboratory data obtained from tests on a rectangular rockfill dam, performing dimensional analysis, and using linear regression, an exponential relationship between the required discharge to transport the sediments through the body of rockfill dam, the physical characteristics of rockfill dam, size of the sediments, and the hydraulic characteristics of the flow passing the dam, is prevented. When we investigated the validity of exponential relationship, we found a good accuracy for the equation indicating that the introduced relation predicts the nondimensional sediment transport capacity well.
Keywords: Control structures, Rockfill dams, Critical hydraulic gradient, Noncohesive sediments
Research Article
A.R. Heidary; R. Choukan; A. Tashakori; H. Kalantari
Abstract
Abstract
To determine the effects of different levels of drought stress on yield and yield components of corn hybrids as well as to determine the correlation between the characteristic and yield in different level of stress a experimental study was done in split plot with 15 corn hybrids placed in Gharakheil. ...
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Abstract
To determine the effects of different levels of drought stress on yield and yield components of corn hybrids as well as to determine the correlation between the characteristic and yield in different level of stress a experimental study was done in split plot with 15 corn hybrids placed in Gharakheil. the main plot was contained different levels of stress(a1:irrigation after 50mm evaporation from small tub evaporation. a2: irrigation after 90mm evaporation from small tub evaporatio. a3: irrigation after 130mm evaporation from small tub evaporation. a4:irrigation after 170mm evaporation from small tub evaporation. ) and sub plot contained corn hybrids. in normal ,mild and severe stress conditions OSGT14 hybrid respectively with 9. 445,9. 270 and 8. 352 ton/hac had the highest yield. in the severest stress condition SPGT12 hybrid with 7. 445 ton/hac had the highest yield. in the yield components, the weight of 1000 grains,the number of grains in rows,the number of grains in an ear of corn,biological yield,harvest indices and the geight and thickness of an ear of corn showed the most correlation with yield. . in other word,this characteries are having the most important effect on the yield. the correlation between tolerance indicies can be a factor in choosing the best hybrid and the best indices. where as there is a high correlation between MP, GMP, HARM and STI, in the other hand, these indices are having the highest correlation with yield in normal condition and different level of stress ,they can be called the most important indices. with the help of these indicies, probable delicate variaties can be distinguished.
Keywords: Drought stress, Corn, Tolerance indices
Research Article
N. Najafi; S. Mardomi
Abstract
چکیده
تأثیر مدت غرقاب شدن خاک، منبع و مقدار کود آلی بر ویژگی های رشد گیاه آفتابگردان ((Helianthus annuus L. در شرایط گلخانه ای بررسی گردید. آزمایش به صورت فاکتوریل و در قالب طرح ...
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چکیده
تأثیر مدت غرقاب شدن خاک، منبع و مقدار کود آلی بر ویژگی های رشد گیاه آفتابگردان ((Helianthus annuus L. در شرایط گلخانه ای بررسی گردید. آزمایش به صورت فاکتوریل و در قالب طرح پایه کاملاً تصادفی با سه تکرار شامل مدت غرقاب در پنج سطح (0، 2، 4، 8، 22 روز) و منبع و مقدار کود آلی در پنج سطح )شاهد، 15 گرم کود گاوی، 30 گرم کود گاوی، 15 گرم لجن فاضلاب و 30 گرم لجن فاضلاب بر کیلوگرم خاک( انجام شد. نتایج نشان داد که با افزایش مدت غرقاب شاخص کلروفیل برگها، وزن تر و خشک ریشه و بخش هوایی و نسبت وزن خشک بخش هوایی به ریشه کاهش یافتند ولی ارتفاع گیاه و قطر ساقه در محل طوقه افزایش یافتند و سطح برگها تغییر معنی داری نکرد. با کاربرد هر دو کود آلی شاخص کلروفیل، سطح برگها، قطر ساقه در محل طوقه، وزن تر و خشک ریشه و بخش هوایی و نسبت وزن خشک بخش هوایی به ریشه افزایش یافتند ولی ارتفاع گیاه تغییر معنی داری نکرد. اثر متقابل غرقاب و کود آلی بر شاخص کلروفیل برگها، سطح برگ و نسبت وزن خشک بخش هوایی به ریشه معنی دار بود ولی بر سایر صفات مورد مطالعه معنی دار نبود. بیشترین وزن تر بخش هوایی و ریشه و سطح برگها در تیمار بدون غرقاب و کاربرد 30 گرم لجن فاضلاب بر کیلوگرم خاک مشاهده گردید. لجن فاضلاب رشد بخش هوایی و ریشه آفتابگردان را بیشتر از کود گاوی افزایش داد. حساسیت ماده خشک بخش هوایی آفتابگردان به تنش غرقاب بیشتر از ماده خشک ریشه بود.
واژه های کلیدی: آفتابگردان، رشد، غرقاب، کود آلی، لجن فاضلاب
Research Article
M. Rahimizadeh; A. Zare Feizabadi; A. Kashani; A.R. Koocheki; M. Nassiri Mahallati
Abstract
Abstract
This study was conducted under cold climate condition in Khorasan during 2006-2008 growing seasons to evaluation of soil fertility in wheat-based double cropping systems under different rate of nitrogen and return of crop residues. A randomized complete block design with split-split plot arrangement ...
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Abstract
This study was conducted under cold climate condition in Khorasan during 2006-2008 growing seasons to evaluation of soil fertility in wheat-based double cropping systems under different rate of nitrogen and return of crop residues. A randomized complete block design with split-split plot arrangement and three replicates was used. Main plots were five crop rotations namely: wheat-wheat, potato-wheat, silage corn-wheat, clover-wheat and sugar beet-wheat. Four sub plots were, N fertilizer rates in preceding crop including no N (control), 50% lower than recommended N rate, recommended N rate and 50% more than recommended N rate. The two sub-sub plots were preceding crop residue return including: no residue return (control) and 50% residue return. Results showed that soil nitrogen content was not affected by crop rotation, nitrogen rate and return of crop residues. Soil phosphorus content at 30-cm depth was significantly affected by preceding crop of wheat. Although, nitrogen rate and crop residue return were not influenced on soil phosphorus. Our results indicated that soil potassium content observed for the clover and wheat, respectively. There was a significantly interaction between preceding crop and return of crop residue for soil organic carbon in the 30 to 60 cm depth. But, soil organic carbon was not affected by preceding crop and nitrogen rate in the first year of experiment.
Keywords: Crop rotation, Nitrogen, Phosphorus, Organic carbon, Wheat
Research Article
B. Rajabi; H. Khodaverdiloo; A. Samadi; M.H. Rasouli Sadaghiani
Abstract
Abstract
The availability of heavy metals in the soil is related to their partitioning between solution and solid phases and expressed by sorption isotherm. Twenty surface soil samples (0-30 cm) belonging to five soil subgroups were taken from agricultural regions of Western Azerbaijan province. The ...
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Abstract
The availability of heavy metals in the soil is related to their partitioning between solution and solid phases and expressed by sorption isotherm. Twenty surface soil samples (0-30 cm) belonging to five soil subgroups were taken from agricultural regions of Western Azerbaijan province. The sorption isotherms of Pb were determined by equlibrating the soil with solutions containing 0, 100, 300, 500, 700, 900, 1100 and 1300 mg Pb L-1 from Pb-nitrate source in 0.01 M NaNO3 as background electrolyte. Illite was the dominant clay mineral in Typic Calcixerepts (TC), Typic Haploxerepts (TH) and Typic Endoaquepts (TE) whereas in Vertic Calcixerepts (VC) and Vertic Endoaquepts (VE) the clay mineralogy was dominated by smectite. Active and equivalent calcium carbonate and clay contents ranged from 4.3 to 7.8%, 6.2 to 16% and 31 to 45%, respectively. The linaer, Langmuir and Freundlich isotherm equations were fitted to the experimental data of Pb sorption and desorption. Both the Freundlich (0.98< R2
Research Article
R. Hamzenejad Taghlidabad; H. Khodaverdiloo; Sh. Manafi; S. Rezapour
Abstract
Abstract
Nowadays, environmental pollution by heavy metals is one of the most serious threats of the world which needs effective remediation actions. The aim of this study was to investigate the potential use of Atriplex [Atriplex verucifera], Salicornia [Salicornia europaea] and Chenopodium Album in ...
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Abstract
Nowadays, environmental pollution by heavy metals is one of the most serious threats of the world which needs effective remediation actions. The aim of this study was to investigate the potential use of Atriplex [Atriplex verucifera], Salicornia [Salicornia europaea] and Chenopodium Album in simultaneous uptake and accumulation of Na and Cd or Pb in two calcareous soils with different properties. Two soils, including a saline-sodic-calcareous (S1) and a calcareous (S2) soil, were selected. Different concentrations of Pb (0, 250, 500 and 1000 mg Pb kg-1 soil) and Cd (0, 10, 30 and 100 mg Cd kg-1) were then added to the soils. . The contaminated soils were incubated under a wetting-drying moisture regime for nearly seven months. The plants seeds were grown in pots containing different treatments of polluted soils and in control treatment (no Cd and Pb contaminations). The plant yields and concentrations of Pb, Cd and Na in the soil and plant samples were measured. Results showed that relative yield of Salicornia was more in soil S1, whereas those of Atriplex and Chenopodium Album were more in soil S2. In saline- sodic soil, the values of Na bioconcentration factor (BCENa) in control treatment were 67, 202 and 57 for Atriplex, Salicornia and chenopodium album respectively. The high value of BCENa in Salicornia revealed the ability of this plant in absorption and accumulation of Na from soil. A considerable accumulation of soil Cd by Salicornia and Pb accumulation by Atriplex and Salicornia was observed under unsuitable conditions of the saline-sodic soil, whereas, Atriplex and Chenopodium had high capability for Cd in the soil S2. These results revealed that these plants could be used for remediation of Pb and Cd contaminated soils. In this study, Salicornia with lower rate of yield reduction had the highest tolerance to Cd-stress and it seems that one can use this plant for phytiremediation of Cd and Pb from saline- sodic soil even in high concentrations of Cd and Pb.
Keywords: Bioaccumulation, Sodium (Na), Lead (Pb), Cadmium (Cd), Halophyte plants
Research Article
A. Hadinezhad; H. Khademi; Sh. Ayoubi; H. Lotfi Parsa
Abstract
Abstract
Heated micaceous minerals under different commercial brand names (including vermiculite) are used as culture medium in greenhouses. Heating minerals affects the release of elements, such as potassium, by changing their structure. The present study, investigates the ability of alfalfa, as one ...
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Abstract
Heated micaceous minerals under different commercial brand names (including vermiculite) are used as culture medium in greenhouses. Heating minerals affects the release of elements, such as potassium, by changing their structure. The present study, investigates the ability of alfalfa, as one of the most important fodder around the world, to take up the non-exchangeable and structural potassium from heated micaceous minerals. The simultaneous effects of heat treatments and rhizospheric conditions on potassium release from two heated micaceous minerals including muscovite, as a di-ochtahedral mica, and phlogipite, as a tri-ochtahedral one, were studied in a pot experiment. The experiment was carried out as a completely randomized design with factorial combinations and three replications. Minerals were heated at 100 to 900 0C for 5 hours and mixed with quartz sand to fill the pots as the culture medium. Pots were irrigated with two different nutrient solutions (+K or -K) and distilled water during a period of five months. At the end of experiment, dry matter of shoot and root samples was measured separately. The K uptake by plant was then measured by flame photometer following the dry ash extraction. Results revealed different responses of micaceous minerals to heat treatments. In K-free treatments, the plant K uptake was significantly influenced by culture media. The most plant K available was released at 100 and 200 0C for muscovite and phlogopite treated plants, respectively. The structural changes causing a considerable decrease in potassium release, also took place at 700 0C for phlogopite and 500 to 700 0C for muscovite.
Keywords: Heat treatments, Potassium release, Muscovite, Phlogopite, Alfalfa
Research Article
H.R. Jalili; A. Hosseinzadeh Dalir; D. Farsadizadeh
Abstract
Abstract
One of the most important sources of drinking and agricultural water needs is rivers. One of the oldest methods of getting water from rivers that still has the greatest use is the gravity intake. In this type of intake, due to the disproportionate velocity at the upstream and downstream mouth ...
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Abstract
One of the most important sources of drinking and agricultural water needs is rivers. One of the oldest methods of getting water from rivers that still has the greatest use is the gravity intake. In this type of intake, due to the disproportionate velocity at the upstream and downstream mouth of intake, occur flow separation and following sedimentation at the upstream mouth. In this study, by use of a numerical model (SSIIM 2.0) optimized hydraulic mode of intake, so that the minimum flow separation at the upstream mouth occurs, then similar models was performed in the physical model. Results indicated that the optimum model of numerical model and the optimum of physical model (based on sedimentation data) is the same. The optimal model is 7 in 63 cm combined arc at the upstream mouth.
Keywords: Vertical lateral intake, Flow separation, Secondary flows, Numerical model, SSIIM 2
Research Article
M. Davari; M. Homaee
Abstract
Abstract
Soil Contamination by heavy metals is yet one of the most important environmental concerns. Among heavy metals, Nickel and Cadmium have dangerous influences on human, animals and plants. The objective of this study was to derive a new model for simultaneous phytoextraction of Ni and Cd from ...
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Abstract
Soil Contamination by heavy metals is yet one of the most important environmental concerns. Among heavy metals, Nickel and Cadmium have dangerous influences on human, animals and plants. The objective of this study was to derive a new model for simultaneous phytoextraction of Ni and Cd from contaminated soils. Consequently, a macroscopic model was derived by combining yield reduction functions and relative concentrations of Ni and Cd in plant tissues. To verify the derived model, a clay loam soil was simultaneously contaminated with different concentrations of Ni and Cd. The Ornamental Kale seeds were then seeded in these packed contaminated soils in three replicates. Plants were harvested after full development. The Ni and Cd contents of soil samples and plant materials were extracted by 4M HNO3 oxidation and wet oxidation methods, respectively. The Ni and Cd concentrations were measured by Atomic Absorption Spectrometer (Shimadzu, AA 670-G) and Inductively Coupled Plasma Optical Emission Spectrometry (Varian Vista-PRO). The results indicated that relative yield of Ornamental Kale in the contaminated soils with both Ni and Cd was reduced more than the soil polluted with separate Cd or Ni. The results also indicated that at any given soil Cd concentration, the Ni content of Ornamental Kale increases with increasing soil Ni concentration. Meanwhile, with increasing soil Cd, the Ni content in Ornamental Kale was decreased. Further, at any given Cd content, the amount of Cd in Ornamental Kale was increased by increasing Ni concentration in soil. The results further indicated that the proposed model can well predict Ni phytoextraction from soils contaminated with both Ni and Cd. However, this model could only provide an overall estimate for Cd phytoextraction. It was further concluded that Ornamental Kale due to its high biomass production and high tolerance to Ni and Cd concentrations can be used to remediate low to moderate combined Ni -Cd contaminated soils.
Keywords: Cadmium, Multiplicative theory, Nickel, Ornamental kale, Phytoextraction
Research Article
V.R. Verdinejad; S. Besharat; H. Abghari; H. Ahmadi
Abstract
Abstract
To optimal use of available water, irrigation scheduling is important to over scarcity of water resources in arid and semi-arid area. In this research to estimate of maximum allowable deficit (or: management allowed depletion) and irrigation scheduling of Fodder Mays based on canopy-air temperature ...
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Abstract
To optimal use of available water, irrigation scheduling is important to over scarcity of water resources in arid and semi-arid area. In this research to estimate of maximum allowable deficit (or: management allowed depletion) and irrigation scheduling of Fodder Mays based on canopy-air temperature difference, a field study was conducted in agricultural faculty of Karaj. The lower limit baseline (potential transpiration) and upper limit baseline (zero transpiration) were estimated by a wet treatment: (keeping soil water content at Field Capacity) and a dry treatment: (complete depletion of available water), respectively. To estimate the maximum allowable deficit, four soil moisture depletion to permanent wilting point treatments were applied in four different growth stages including settlement, vegetating, flowering and ripening of Fodder Mays with three replications. The measured data were wet and dry air temperature, canopy temperature, air relative humidity, root depth, soil water content in root depth and air vapor pressure and based the measured data, equations were extracted for lower and upper limit baselines of Fodder Mays. By comparison of canopy-air temperature difference of four treatments of soil moisture depletion with wet treatment, the maximum allowable deficit for four growth stages were estimated 42.8, 59.2, 58.9 and 67.5 percentages, respectively. The location of upper limit baseline (zero transpiration) was obtained +3.2 °C based on dry treatment. To irrigation scheduling in different growth stages by canopy-air temperature difference, crop water stress index was used and irrigation time was determined by direct method of canopy temperature.
Keywords: Canopy temperature, Evapotranspiration, Fodder Mays, Irrigation scheduling, Karaj
Research Article
A. Jafari; Sh. Ayoubi; H. Khademi
Abstract
چکیده
شناسایی رقومی خاک ها بهعنوان ابزاری برای ایجاد اطلاعات مکانی خاک، راه حل هایی برای نیاز رو به افزایش نقشه های خاک با تفکیک مکانی بالا را تأمین می کند. بنابراین، ...
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چکیده
شناسایی رقومی خاک ها بهعنوان ابزاری برای ایجاد اطلاعات مکانی خاک، راه حل هایی برای نیاز رو به افزایش نقشه های خاک با تفکیک مکانی بالا را تأمین می کند. بنابراین، باید روش های جدید بهمنظور بهدست آوردن اطلاعات مکانی خاک با تفکیک مکانی بالا توسعه پیدا کند. به همین منظور مطالعه ای جهت پیش بینی کلاس های خاک با استفاده از مدل های رگرسیونی در منطقه زرند کرمان طراحی گردید. در این مطالعه، مدل های رگرسیونی شامل رگرسیون لاجیستیک چندجمله ای و رگرسیون درختی توسعه یافته چندکلاسه برای پیش بینی گروه بزرگ خاک به کمک داده های سنجش از دور، پارامترهای سرزمین و نقشه ژئومرفولوژی استفاده گردید. کیفیت پیش بینی مدل ها با شاخص های حاصل از آرایه خطا بررسی گردید. نتایج نشان داد در پیش بینی همه گروه های بزرگ خاک، سطوح ژئومرفیک بهعنوان یک پیش بینی کننده مؤثر محسوب می شود. بعد از سطوح ژئومرفیک، پارامترهای سرزمین و شاخص های سنجش از دور در پیش بینی وارد شدند. در هر دو مدل خلوص نقشه برای همه گروه های بزرگ خاک در موقعیت های اعتبارسنجی و واسنجی بیشتر از 6/0 بود. نتایج نشان داد عملکرد پیش بینی برای گروه های بزرگ هاپلوجیپسید و هاپلوسالید بهتر از گروه های بزرگ کلسی جیپسید و هاپلوکمبید بود. در بین گروه های بزرگ خاک، مقادیر بالای دقت کاربر و قابلیت اطمینان تولیدکننده برای گروه بزرگ هاپلوسالید بهدست آمد. خاک های با قابلیت اطمینان بهتر خاک هایی هستند که به شدت تحت تأثیر مشخصات توپوگرافی و ژئومرفولوژی قرار گرفتند (گروه های بزرگ هاپلوسالید، تری سامنت و هاپلوجیپسید) و خاک های با قابلیت اطمینان و دقت پیش بینی کمتر خاک هایی هستند که به سختی تحت تأثیر مشخصات توپوگرافی و ژئومرفولوژی (گروه های بزرگ هاپلوکمبید و کلسی جیپسید) قرار گرفتند.
واژه های کلیدی: نقشه برداری رقومی خاک، رگرسیون لاجیستیک چندجمله ای، رگرسیون درختی توسعه یافته
Research Article
F. Modaresi; Sh. Araghinejad; K. Ebrahimi; M. Kholghy
Abstract
Abstract
Climate change means a significant change in the long-term weather of a region in comparison with what has been observed during a long term period. Precipitation and minimum and maximum temperature are three variables which are affected directly by the climate change. Furthermore, the water ...
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Abstract
Climate change means a significant change in the long-term weather of a region in comparison with what has been observed during a long term period. Precipitation and minimum and maximum temperature are three variables which are affected directly by the climate change. Furthermore, the water yield of a river is one of the most important hydrological variables of a Basin which is affected by variations of the climate variables. In this research, the mentioned variables have been used to assess the climate change, and precipitation, the most important factor affecting water yield, has been used to investigate the climate change effect on the water yield of the river. A conditional probability distribution function has been used to determine the quantity of the annual water yield of a river. This approach gives a variation range demonstrating the error existing in the results. In this paper, the Gorganroud basin is selected as the case study. Precipitation and minimum and maximum temperature of the basin during the 1977-2006 have been compared with the output of scenarios of all Global Circulation models to select the most appropriate model to forecast the future climate of this basin. The obtained results show that the scenario B2 of HadCM3 model is the most appropriate scenario for this case study. If this scenario happen in the next 30 years, the quantity of water yield in Tamr station adjacent to Gorganroud river, located upstream of Boostan, Golestan and Voshmgir dams, will decrease 1.38% and 1.33% in water yield volume of return periods of 50 and 100 years, respectively. But, if the existing trend in historical data continues in the next 30 years, the quantity of water yield at this station will increase 14.94% and 14.55% in water yield volume of return periods of 50 and 100 years, respectively.
Keywords: Water yield, Climate change, Conditional probability distribution function, Gorganroud
Research Article
M. Pourmandegari Mehrjardi; M. Zokaii; H. Ejtehadi
Abstract
Abstract
The aim of this study was the identify cyanobacterial flora of rice–fields in Dargaz, to interaction between cyanobacteria by culturing in solid medium BG-110 in laboratory was investigated. Nostoc piscinale and Nostoc spongiaeforme were identified as strongest and weakness species, respectively, ...
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Abstract
The aim of this study was the identify cyanobacterial flora of rice–fields in Dargaz, to interaction between cyanobacteria by culturing in solid medium BG-110 in laboratory was investigated. Nostoc piscinale and Nostoc spongiaeforme were identified as strongest and weakness species, respectively, regarding secondary metabolits producing (allelochemicals).The algal pairs were classified in two groups based on their interactions. Possibility of using blue-green algae allelochemicals to combat harmful algae blooms (HABs) and agriculture science was discussed.
Keywords: Blue-green algae, Secondary metabolites, Allelochemicals, Allelopathy
Research Article
S.A. Mohseni Movahed; M. Akbari
Abstract
Abstract
Due to limited water resources in agriculture, application of each strategy to economize water use and increase area under cultivation is very important. One such strategy is deficit irrigation. For optimal planning of deficit irrigation, it is necessary to determine different sensitive stages ...
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Abstract
Due to limited water resources in agriculture, application of each strategy to economize water use and increase area under cultivation is very important. One such strategy is deficit irrigation. For optimal planning of deficit irrigation, it is necessary to determine different sensitive stages of plant water shortages. In this study the effect of deficit irrigation on growth and yield of irrigated wheat (Alvand cultivar) in Hamedan area was investigated to determine crop yield response factor to water (Ky) and performance sensitivity coefficient (λi) elimination of irrigation at varios stages were used. Thus the cultivation of winter wheat in Farm of Bu-Ali Sina University was under deficit irrigation using a randomized complete block design with six irrigation treatments and three replication during two consecutive years (2004-2006). Results showed that low irrigation treatments reduced grain yield, dry matter yield and thousand kernel weight. The flowering period (with sensitivity factor of 1.96) was the most sensitive periods toward water deficit irrigation and the elimination of irrigation in this stage will reduce yield more. Elimination of Irrigation in milky doughy stage (with a coefficient of reaction 1.67) showed the most performance reaction to the low irrigation. Reduction of water use efficiency in these stages in comparison with the complete irrigation in this stages indicates irrigation in these stages are necessary. Other results indicate that one irrigation turn may be eliminated in one of the stem elongation or seed hardening stages without any significant decrease in yield and harvest index.
Keywords: Deficit irrigation, Alvand cultivar wheat, Sensitivity performance coefficient, Reaction performance coefficient, Flowering stage
Research Article
M. Salehi; M. Kafi; A.R. Kiani
Abstract
Abstract
In order to optimize the water management in agriculture in semi arid and arid conditions water-salinity function should be evaluated. In order to evaluate salinity and deficit irrigation two experiments were conducted in 2008 and 2009. Kochia was grown with six levels of saline water (1.5, ...
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Abstract
In order to optimize the water management in agriculture in semi arid and arid conditions water-salinity function should be evaluated. In order to evaluate salinity and deficit irrigation two experiments were conducted in 2008 and 2009. Kochia was grown with six levels of saline water (1.5, 7, 14, 21, 28, and 35 dS/m) and three levels of applied water (25, 75, and 125 percent of the water requirement) in 2008 and four levels of applied water (50, 75, 100, and 125 percent) in 2009. Data were analyzed using linear, quadratic, Cobb-Douglas and transcendental functions. Results showed that quadratic function estimated yield better under salinity and water stress. Marginal rate of technical substitution showed that water salinity and water supply can be substituted with the other in a wide range in order to achieve equal amount of yield. Marginal production of water quantity and quality were 6.7 and 154 kg.ha-1 in 2008 and 4.8 and -511 kg.ha-1 in 2009, respectively.
Keywords: Production function, Halophyte, Water quality, Water quantity
Research Article
M. Panahi; S.M. Mirlatifi; F. Abbasi
Abstract
Abstract
This study addresses two dimensional infiltration from irrigated furrows. The basic approach is to develop a two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The edge effect is the difference between the cumulative infiltration ...
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Abstract
This study addresses two dimensional infiltration from irrigated furrows. The basic approach is to develop a two-dimensional infiltration as a combination of the corresponding one-dimensional vertical and an edge effect. The edge effect is the difference between the cumulative infiltration per unit of adjusted wetting perimeter and the corresponding one-dimensional infiltration. This approach was evaluated using field measured furrow experiments and double ring infiltration tests. In this study, two series of experiments was conducted in 2010 on a clay loam soil. The first series of the tests included five experiments with inflow rate (0.3-0.8 ls-1) on free draining furrows having 110 meters in length, 75 cm wide and general slope of 0.008 m m-1. The second series of the experiments were carried out using double ring. A general conclusion was that the edge effect was linearly related to time. Using minimizing root mean square error (RMSE) the two empirical coefficients of the model including γ and W*/W were determined. The values of 0.62 and 1.15 were determined for the two empirical parameters in the clay loam soil studied. The results showed that the RMSE and the absolute error (AE) were 0.0031 and5.9 %, respectively. Model sensitivity analysis showed that the lowest sensitivity was to initial water content and the highest sensitivity was to saturation water content. The approach leads to an infiltration function for irrigation furrows without the need to perform a fully two-dimensional simulation.
Keywords: Furrow irrigation, Two-dimensional infiltration models, Warrick model, Edge effect
Research Article
M. Navabian; M. Aghajani; M. Vazifehdost; M. Rezaei
Abstract
Abstract
Rice is most important agricultural crop of Guilan province sensibility to salinity and alkalinity of water and soil. In recent years, using of toxicants and fertilizers in farmlands, constructing several dams upstream, entering agricultural, homemade and industrial sewage in to a river, and ...
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Abstract
Rice is most important agricultural crop of Guilan province sensibility to salinity and alkalinity of water and soil. In recent years, using of toxicants and fertilizers in farmlands, constructing several dams upstream, entering agricultural, homemade and industrial sewage in to a river, and drought have decreased gradually discharge of river and increased salinity of Sefidrud River as an irrigation source of Sefidrud irrigation network of Guilan province. This research tries to determine the optimal intermittent and depth of irrigating of rice in proportion to salinity of Sefidrud River using of optimization- simulation mechanisms as is the decrease in crop efficacy become minimum. To achieve this, an agro hydrological SWAP was used to simulate different stages of rice growing and an optimization model was used in a reasonable range of the intermittent rice irrigation period and depth with regard to different growth stages. Because some types of rice are affected by salinity, field experiments of Hashemi variety in Rasht in 1386 were used to calibrate the model. Optimal values of the intermittent irrigation regime in current salinity of the Sefidrud River (1.747 ds/m) included 8 days intermittent irrigation period and the depth of water for irrigating was 1, 3, 4 and 5 for vegetative, tiller, maturity and harvest stages respectively. The comparison of results of optimization- simulation model with field data in 1389 showed good efficiency of this model in irrigation optimization. In the field experiment 8 days intermittent period with irrigation 5 cm in depth was highest crop performance in 2 ds/m salinity.
Keywords: Rice, Intermittent irrigation management optimization, Sefidrud, Salinity, SWAP model
Research Article
A. Faalian; H. Ansari; S.A.A. Sadredini
Abstract
Abstract
A model based on Fuzzy Logic has been developed to simulate the distribution pattern of a single sprinkler. A Nelson R3000 sprayer with rotator pad and water application angle of 360o which is one of the most common types of center pivot and linear move sprinklers was selected. Several field ...
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Abstract
A model based on Fuzzy Logic has been developed to simulate the distribution pattern of a single sprinkler. A Nelson R3000 sprayer with rotator pad and water application angle of 360o which is one of the most common types of center pivot and linear move sprinklers was selected. Several field experiments according to the ISO-8026 and ASAE-S398.1 standards were performed to assess the water distribution pattern in no-wind and windy conditions at the Research Center of Agricultural Faculty, University of Tabriz-Iran. Results of thirty reliable experiments were used to educate & validate the model. Minimum and maximum wind speeds recorded under the field conditions were 0.57 and 7.41 ms-1, respectively. In order to comparative analyze between simulated values and observations several statistical criteria like R2, CD, EF, CRM, MAE and RRMSE were used. For the training dataset the average values of R2 and RRMSE were achieved 0.98 and 0.257, respectively. Also the values of parameters R2 and RRMSE for the validation dataset were calculated 0.96 and 0.34 respectively. As well as the other above mentioned statistical parameters for both training dataset and validation dataset were found satisfactory. To make the results practical a model was developed as a MATLAB m-file, using Fuzzy Logic that takes wind velocity and direction as the inputs and could simulate the distribution pattern of single sprinkler and have ability to display graphical and Excel file of results. With the statistical comparisons between simulated water distributions patterns with observed ones it was finally concluded that Fuzzy model had excellent ability to simulate the water distribution pattern.
Keywords: Water Distribution Pattern, Single Sprinkler, Fuzzy Logic, Simulation, Center Pivot
