Research Article
M.R. Shayestehfar; N. Shafiee; H. Shirani; A. Rezaei; M.R. Kargar Dianati
Abstract
In recent years, the study of soil contamination problems surrounding the mines and smelting plants has attracted the serious attention of the environmental experts. In Iran, due to the mining and mine development, the study of environmental problems seems to be obligatory. The main point of this research ...
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In recent years, the study of soil contamination problems surrounding the mines and smelting plants has attracted the serious attention of the environmental experts. In Iran, due to the mining and mine development, the study of environmental problems seems to be obligatory. The main point of this research is the implications of the statistical and geostatistical studies to evaluate and prepare elemental dispersion map of the As and Se elements around the soil of the Sarcheshmeh copper mine area. To investigate the rate of concentration of heavy metals, the path of sampling selected in three different directions. From the area in which the chimneys of the smelting plant of the Sarcheshmeh copper factory is at the centre within a radius of 6 kms, which is collected for the number of 120 soil samples from the surface with the maximum of 30 centimeters depth from the entire area were collected from the original areas and were interpreted after the analysis by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Initially, the necessary statistical parameters have been done with respect to the data distribution. Therefore, variogram used for the variation justification of all the directions and the parameters of variogram model was processed and estimated by kriging jack knife method. Eventually the contaminated As and Se areas were identified respectively with the help of normal kriging estimator. With the use of the produced maps, the perquisite conclusion was the possible concentration of As element around the chimneys which is more than the rest of the places and dominated wind blow direction, that is towards the Rafsanjan city. Also about the Se, the result exhibited that, unlike As, the wind direction has no effect on the dispersion of it and the transmittal rate is related to the geological characteristic of the study area.
Research Article
M.S. Hosseini; Gh. Haghnia; A. Lakzian; H. Emami
Abstract
Soil enzyme activities can be used as indicators of soil quality for assessing the sustainability of agricultural ecosystems. The objective of this study was to determine the effects of barley residue input rate, burning, urea fertilizer and tillage management on activities of alkaline phosphatase and ...
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Soil enzyme activities can be used as indicators of soil quality for assessing the sustainability of agricultural ecosystems. The objective of this study was to determine the effects of barley residue input rate, burning, urea fertilizer and tillage management on activities of alkaline phosphatase and urease under field conditions, after a period of 90 days. The experiment was carried out based on a completely randomized design with a factorial arrangement in two replications. The treatments included two levels of barley residue input rate (3 and 6 t ha-1), burning (without and with stubble burning), urea fertilizer (0 and 125 kg ha-1) and tillage systems (no-till, conventional tillage). Results showed that 6 t ha-1 crop residue treatment increased enzyme activities in comparison with 3 t ha-1treatment at 0-5 cm. Whereas stubble burning and tillage treatments significantly decreased urease and alkaline phosphatase activities. The urea fertilizer had no effect on alkaline phosphatase activity, whereas urease activity positively affected by urea application. Urease activity was affected more than alkaline phosphatase activity by management practices in soil. The results of this experiment showed that no-tillage system along with crop residue retention of 6 t.ha-1 and without stubble burning systems would be the most effective management to protect and promote soil alkalin phosphatase and urease activity.
Research Article
H. Dehghan Manshadi; M.A. Bahmanyar; A. Lakzian; S. Salek Gilani
Abstract
Sewage sludge with having the organic matter is considered as a source of micro and macro elements. In order to investigate the effect of different levels and period of application of sewage sludge (SS) on organic matter, respiration, and acid and alkaline phosphatase activity, factorial design were ...
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Sewage sludge with having the organic matter is considered as a source of micro and macro elements. In order to investigate the effect of different levels and period of application of sewage sludge (SS) on organic matter, respiration, and acid and alkaline phosphatase activity, factorial design were studied, in 3 replications. Sewage sludge at five levels, (20 and 40 tons of sewage sludge, 20 and 40 tons of sewage sludge + 50 percent of chemical fertilizers (CF) per hectare, without taking sewage sludge) and period of application three levels (two, three and four years) was considered. The results showed that application of SS at all levels, increased soil organic carbon (O.C) and soil microbial respiration and enzyme activity were compared with the controls (p
Research Article
A. Hosseinpour Buri Abadi; Gh. Haghnia; A. Alizadeh; A. Fotovat
Abstract
Increasing population, limitation of water resources, and also enormous volume of municipal wastewater and need to dispose of these wastewaters safety, has been increased of necessity of reuse of wastewater. Disposal of wastewater in soil is one of the most economical methods of their disposal. Different ...
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Increasing population, limitation of water resources, and also enormous volume of municipal wastewater and need to dispose of these wastewaters safety, has been increased of necessity of reuse of wastewater. Disposal of wastewater in soil is one of the most economical methods of their disposal. Different soil characteristics, type of wastewater and method of its application are issues that affect wastewater treatment efficiency in the soil. For this purpose, an experiment was carried out in 12 polyethylene columns during 7 periods of 15 days in Ferdowsi University of Mashhad. A statistical “factorial design” was used. Raw and treated wastewaters from Parkandabad Treatment Plant were applied under continuous and intermittent flood conditions in columns filled with silty loam soil. At the end of experiment, soil columns were divided and soil samples from depths of 0-25, 25-50 and 50-100 cm each column were collected. Properties such as pH, salinity, concentration of NO3, PO4, TOC, Ni and Cd were measured in soil solution samples and also Leachates were taken in each period of experiment. The result showed that the mean values of each of the above mentioned parameters, with exception of pH and salinity, were lower in leachate compared to the wastewaters entering the soil. However, with continuous application of wastewaters increase in the amount of these components (with exception of salinity and Ni) were observed. The amount of Cd in leachate samples of any periods was undetected. Considering the effect of wastewater application on soil chemical properties, value of all parameters (except salinity) in comparison to their initial values have increased in the soil solution. Based on the above results, disposal of wastewaters (especially raw wastewater) on soil should be managed carefully. So that by sound usage of wastewaters, environmental risks resulting from disposal of them are reducing to the lowest level in nature.
Research Article
N. Sedaghati; S.J. Hosseinifard; A. Mohammadi Mohammadabadi
Abstract
Unsustainable harvesting of agricultural water resources in the province of Kerman, has caused an annual average of one-meter drop in ground water levels. Surface irrigation methods in pistachio trees have low efficiency because of inherent characteristics and its incorrect application, as well as low ...
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Unsustainable harvesting of agricultural water resources in the province of Kerman, has caused an annual average of one-meter drop in ground water levels. Surface irrigation methods in pistachio trees have low efficiency because of inherent characteristics and its incorrect application, as well as low access to water resource in pistachio regions. Therefore under the current critical condition, basic development of pressurized irrigation systems is an effective step to raise water use efficiency in the pistachio orchards. In this research, two irrigation systems including conventional surface drip irrigation and subsurface drip irrigation (SDI) with two drip line depths (30cm and 50cm) with three levels of water irrigation in each treatment, including 40%, 60% and 80% of irrigation requirement of pistachio in surface irrigation system (2932, 4398 and 5864 m3/ha.year respectively) for four years, was studied. Growth and yield factors, water use efficiency (WUE) and water and salinity distribution in root zone were measured. The results indicated that 30cm installation depth was the best treatment. Between irrigation systems, amounts of 60% and 80% irrigation requirement don't have significant difference, but 40% irrigation requirement treatment, affected negatively on most of evaluated factors significantly. Therefore with regard to all evaluated factors in this research, subsurface drip irrigation with buried drip line at 30cm and 60% of irrigation requirement of pistachio in surface irrigation system, with water use efficiency of 0.290kg/m3 and 25% water saving in comparison with surface drip irrigation system, was the best treatment and recommended.
Research Article
Sh. Shafaei; A. Fotovat; R. Khorasani
Abstract
Iron (in zero-valent and oxide forms) is used to remove numerous organic and inorganic contaminants in environment. However, there are few reports, especially in nano scale, on the remediation of heavy metals contaminated soils using zero-valent iron in the literature. In this study, the effect of iron ...
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Iron (in zero-valent and oxide forms) is used to remove numerous organic and inorganic contaminants in environment. However, there are few reports, especially in nano scale, on the remediation of heavy metals contaminated soils using zero-valent iron in the literature. In this study, the effect of iron on the availability of heavy metals was evaluated in a calcareous soil spiked with cadmium, zinc, lead and nickel. The soil samples, in a randomized complete design with two replications, were amended with four iron materials including micrometric zero-valent iron (ZVI), nanoscale zero-valent iron (nZVI) and nano and micro scales iron oxides. Then, after 1, 2 and 4 weeks of the experiment, DTPA-extractable heavy metals in soil were determined. Results showed that DTPA extractable heavy metals significantly decreased in soil treated with zero-valent iron, compared to untreated soil The stabilization efficiency of Ni, Cd, Zn and Pb was 28%, 32%, 37% and 28% for ZVI and 12%, 0%, 25% and 21% for nZVI, respectively. In contrast, presence of iron oxides caused significant increase of DTPA extractable heavy metals in soil except for Ni. Moreover, Ni-DTPA decreased significantly with time whereas it was constant for the other elements examined. In this study, the observed capacity for heavy metals removal by ZVI was higher than other treatments whereas the stabilization efficiency of nZVI was not significant in the soil.
Research Article
S. Razi; A. Hosseinzadeh Dalir; F. Salmasi; D. Farsadi
Abstract
In this paper the effectiveness combination of bed sill and collar in reduction of local scour depth at cylindrical piers under clear water flow condition was investigated (V/Vc=0.9). In the first of experiments, the bed sill was located in downstream and different distances from the piers. Results indicated ...
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In this paper the effectiveness combination of bed sill and collar in reduction of local scour depth at cylindrical piers under clear water flow condition was investigated (V/Vc=0.9). In the first of experiments, the bed sill was located in downstream and different distances from the piers. Results indicated that minimum distance of the bed sill from the piers in downstream has maximum reduction of scour depth in front of the piers. The percent reduction of scour depth is about 30% in this case. In continuing the tests, used the collar and bed sill simultaneous. When using the combined of collar (2D) and bed sill (L=0), the percent reduction of scour depth in front of piers is about 42% and more than 98% when using the combined of collar (3D) and bed sill (L=0). The results show that using combined of collar and bed sill have more effect in reduction of local scour around bridge piers.
Research Article
E. Babaeian; M. Homaee; R. Rahnemaie
Abstract
Phytoextraction is a remediation technology for contaminated soils with lead (Pb). The application of chelating agents can be resulted in high efficiency in this method. In current study, the effect of synthetic and natural chelates applicationon efficiency of lead phytoextraction from soil by carrot ...
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Phytoextraction is a remediation technology for contaminated soils with lead (Pb). The application of chelating agents can be resulted in high efficiency in this method. In current study, the effect of synthetic and natural chelates applicationon efficiency of lead phytoextraction from soil by carrot was investigated. The experiment factors were 1) six levels of Pb (0, 100, 200, 300, 500 and 800 mg Pb kg-1 soil, added as Pb(NO3 )2, 2) chelates (EDTA, NTA and oxalic acid, and 3) chelate concentration (0, 2.5, 5 and 10 mmol kg-1 soil). The results indicated that EDTA effectively increased the Pb content in soil solution. At the highest applied rate (10 mmol EDTA kg-1), it resulted in 463-fold increase in extractable Pb, compared to the control treatment. Pb content in the shoot and taproot increased with the chelates application rates.The highest Pb content in the shoot (342.2±13.9 mg kg-1) and root (310 ±15.5 mg kg-1) occurred in 10 mmol kg-1 EDTA when Pb level was 800 mg kg-1. Pbphytoextraction potential increased with increasing thechelate and Pb concentration. Maximum Pb extraction from soil (1208±26.6 g ha-1 yr-1) during growth season occurred in 10 mmol kg-1 EDTA, when soil Pb level was 800 mg kg-1. It may be concluded that carrot can take up high amount of Pb and concentrate it in its roots and shoots. Thus, it can be introduced as a lead accumulator to phytoextractPb from contaminated soils.
Research Article
N. Najafi; S. Mardomi; Sh. Oustan
Abstract
In a greenhouse experiment, the effects of waterlogging, sewage sludge and manure on the uptake and concentrations of P, K, Ca, Mg and Na in root and shoot of sunflower (Helianthus annuus L.) were investigated. A factorial experiment based on completely randomized design with three replications including ...
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In a greenhouse experiment, the effects of waterlogging, sewage sludge and manure on the uptake and concentrations of P, K, Ca, Mg and Na in root and shoot of sunflower (Helianthus annuus L.) were investigated. A factorial experiment based on completely randomized design with three replications including duration of waterlogging at five levels (0, 2, 4, 8, 22 days), source of organic fertilizer at two levels (manure and sewage sludge) and each at three levels (0, 15, 30 grams per kg of soil) was conducted. The results showed that by increasing the duration of soil waterlogging, the P and K uptake and concentration in shoot and root, the concentration of Ca and Na in root, the Mg concentration in shoot, the uptake of Ca and Mg in root and the uptake and concentration of Na in shoot increased but P uptake and concentration in root and K uptake in root and shoot decreased again. By increasing the duration of soil waterlogging, the uptake and concentration of Ca in shoot decreased but the Ca concentration in shoot increased again. The effect of soil waterlogging on the Mg uptake in shoot was not significant. By application of sewage sludge and manure and increasing their amounts, the uptake and concentration of P in shoot and root, the uptake of Ca in shoot and root and the uptake and concentration of Na in shoot increased. The K uptake and concentration in shoot increased by application of manure and increasing its level while decreased by application of sewage sludge. The effect of soil waterlogging on the macronutrients and sodium uptake and concentrations in root and shoot was dependent on the source and amount of organic fertilizer and vice versa. The results demonstrated that even short periods of soil waterlogging (2 days) had considerable long-term effect on the concentrations of elements in plant. Generally, sunflower plant accumulated P, Mg and Na in root and Ca in shoot while the K concentration in root did not differ with shoot significantly.
Research Article
V. Mozafari; L. Omidi
Abstract
A factorial greenhouse experiment as completely randomized design with six replications was conducted to Study the effects of potassium and salinity application on morphological and physiological parameters of pistachio seedling (cv. Badami-e-Zarand) in perlit. Treatments were 2 levels of K (0 and 1 ...
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A factorial greenhouse experiment as completely randomized design with six replications was conducted to Study the effects of potassium and salinity application on morphological and physiological parameters of pistachio seedling (cv. Badami-e-Zarand) in perlit. Treatments were 2 levels of K (0 and 1 mM KNO3) and 3 levels of salinity (0, 100 and 200 mg NaCl kg-1 soil). Prolin and redusing sugars contents whit 3 replications and on two separate time (3 and 6 days after salinity application) measured. A factorial split analyzed to test the trend of this factors so that salinity×pottasium and time were as main and sub factors respectively. Results showed that as salinity increased shoot and root dry weights 17% and 15% increased, respectively. As increasing K consentration from 0 to 1 mM, increased dry weight shoot from 0.885 to 1.007 per pot. 1 mM K application increased the leaf number and stem height. As salinity increased significantly increased Na and decreased Mg of plant. Prolin and redusing sugars contents increased three days after application of salinity treatments while K decreased prolin consentration. redusing sugars content significantly affected by time factor so that redusing sugars consentration redused after 3 days but it wasn’t correct about prolin content
Research Article
V. Yazdani; B. Ghahreman; K. Davari; M.E. Fazeli
Abstract
One of the important aspects of soil is, knowing the relationships between spatial features of soil and quantity in statistical model. The goal of this research is to estimate saturated hydraulic conductivity by regression and Co-Active Neuro-Fuzzy Inference System (ANFIS) with using the parameters of ...
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One of the important aspects of soil is, knowing the relationships between spatial features of soil and quantity in statistical model. The goal of this research is to estimate saturated hydraulic conductivity by regression and Co-Active Neuro-Fuzzy Inference System (ANFIS) with using the parameters of Bulk density, real density, porosity, Fractal dimension of particle size, and clay percent, silt percent, sand percent. So experiment related to saturated hydraulic conductivity calculation and soil physical properties calculation of soil in 54 points which were specified 5 by 5 meters. Also, amount of bulk density based on paraffin Hunk, Fractal dimension of particle size by wet sieve method, the percentage of sand, clay and silt by Hydrometry and saturated hydraulic conductivity above water table by double rings method was measured. The best regression model for Pedo transfer function (PTF) was chosen according to minimized the goal function based on statistical parameters R2, RMSE and MAE. Parameters sand and silt percent, bulk density, real density, Fractal dimension of particle size, and porosity were chosen as input. In PTF amount of R2, RMSE, NRMSE and MAE, are 0.65, 0.017, 0.96 and 0.012 respectively. ANFIS with four layers input includes bulk density, real density, porosity and Fractal dimension of particle size and an output layer with the best performance. In this research, the amount of R2 in the presented ANFIS model in training and test is 0.88 and 0.86 respectively, and RMSE values will be 0.012 and 0.02 respectively. Noticing to sensitivity analysis result, PTF has the least sensitivity than changes in porosity and Fractal dimension of particle size, on the other hand, it has the most sensitivity than changes in the values of bulk density, silt and sand percent. ANFIS model is like PTF is more sensitivity than changes in values of bulk density. In addition, the outcome shows more effect on ANFIS than PTF. Evaluation of models show that estimation in clay soil is not acceptable, in contract contrast its model for estimate saturated hydraulic conductivity in soil texture (lom sandy, lom and silt lom) is suitable.
Research Article
E. Zangene Usefabadi; M. Behzad; S. Boroomand Nasab
Abstract
In this study, the level of cations and anions of saline soil leaching was investigated in laboratory conditions by using of magnetic water. silty loam Soil was poured in 50 cm height and 10 cm diameter pipes while the end of each pipe was closed with a filter paper and a plastic net. leaching was conducted ...
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In this study, the level of cations and anions of saline soil leaching was investigated in laboratory conditions by using of magnetic water. silty loam Soil was poured in 50 cm height and 10 cm diameter pipes while the end of each pipe was closed with a filter paper and a plastic net. leaching was conducted alternatively after passing water through the magnetic field with different intensities. The drained water was collected from the end of soil columns and analyzed chemically in the laboratory. The final results showed that the amount of the leaching of sodium, potassium, chlorine and sulfate in the magnetic treatment was significantly more than control treatment (α
Research Article
A.R. Tavakoli
Abstract
The main purpose of rainfed farming is increasing the water productivity by applying suitable agricultural management including single irrigation (SI) and panting time for wheat varieties. In order to study the SI optimization and determination its optimal program, a field experiment was conducted as ...
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The main purpose of rainfed farming is increasing the water productivity by applying suitable agricultural management including single irrigation (SI) and panting time for wheat varieties. In order to study the SI optimization and determination its optimal program, a field experiment was conducted as split-split plot based on a randomized complete block design with three replications for different wheat varieties at main station of Dryland Agricultural Research Institute (DARI), Maragheh, Iran, during two crop seasons of 2000-2004. The treatments included three panting time, three SI and five wheat varieties (V1=72YRRGP, V2=Fenkang 15/Sefid (seed white), V3=Turkey, 13//F9.10/Maya”S”, V4=Azar2, V5=double cross shahi). On based of water productivity indices, rain water productivity (RWP), irrigation water productivity (IWP), and total water productivity (TWP) optimal program of single irrigation scenarios was 100mm at early, 75mm at normal and 50mm at late sowing date. V3 wheat variety was better than other varieties. At this single irrigation program, maximum single irrigation water productivity (11.3 – 21.3 kg.mm-1) in producing grain yield and stabilized wheat production were obtained
Research Article
E. Sayad; S.M. Hosseini; V. Hosseini; M.H. Salehe Shooshtari
Abstract
Plantations may influence soil fauna directly or indirectly. This research was conducted in order to study the influence of species plantations on soil macrofauna. Plantations of eight tree species including nitrogen fixing trees and non-nitrogen fixing trees based on complete randomized block design ...
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Plantations may influence soil fauna directly or indirectly. This research was conducted in order to study the influence of species plantations on soil macrofauna. Plantations of eight tree species including nitrogen fixing trees and non-nitrogen fixing trees based on complete randomized block design with 3 replicates were established in 1372 in Dez riverside. Soil macrofauna were studied randomly with two 0.5 × 0.5 m2 samples from the 0-25 cm top soil in 1385. Earthworm, formicidae, coleoptera, collembola, araneae, chilopoda, isopoda and gastropoda were found. The average of soil macroinvertebrate abundances and biomass were consistently higher in A. salicina plantations than the other, whereas, E. camaldulensis had the lowest abundances and biomass and the highest richness. Comparison of the arthropods abundances and biomass did not show any significant differences between the different plantations. Comparison of macrofauna abundances and biomass in tow plantation groups were not significantly different. Principal component analyze of plantation species based on soil macrofauna also did not separate the two groups, so we could say that the differences under the diverse species do not relate to their nitrogen fixing property. As soil macrofauna is an important factor in regulating litter decomposition, the study on the relation of their abundance and richness to litter decompositiom is recommended.
Research Article
A. Rashid Shomali; H. Khodaverdiloo; A. Samadi
Abstract
However some of heavy metals such as Zn, are essential for plant growth, their elevated concentrations have toxic effects and may inhibit plant growth. In this study, plant tolerance and Zn uptake and accumulation potential of some weed plant species from Western Azerbaijan region were studied in a soil ...
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However some of heavy metals such as Zn, are essential for plant growth, their elevated concentrations have toxic effects and may inhibit plant growth. In this study, plant tolerance and Zn uptake and accumulation potential of some weed plant species from Western Azerbaijan region were studied in a soil spiked with 0, 1000, 3000 and 6000 mgZn kgsoil-1. Seed of heliotrope (Heliotropium europaeum), Lambsquarter (Chenopodium album), Orach (Atriplex sp.), Amaranth (Amaranthus retroflexus), Millet (Pennisetum glaucum), Alfalfa (Medicago sativa) and purslane (Portulaca oleracea) were grown in pots containing the Zn contaminated soil. At the end of growing season, plants relative yield (RY%), plants shoot metal concentration, metal bioconcentration factor (BCFZn) and plants metal extraction (MEZn( from soil were measured. Results showed that with an exception for Lambsquarter and purslane, plants biomass decreased significantly (P≤ 0.05) with increasing Zn concentration in soil, especially, in higher soil Zn contaminations. Compared with other plants studied, Amaranth had the highest BCFZn and MEZn in blank and 6000 mgZn kgsoil-1 treatments. Amaranth, Lambsquarter and Orach with a relatively high biomass (750 to 960g dry matter bush-1 in native condithios) and middle rate of Zn uptake might be effective in remediation of Zn from contaminated soils
Research Article
M.H. Noori Gheidari
Abstract
The intensity – duration – frequency (IDF) curves play most important role in the hydraulic design of structures. The traditional method to construct IDF curves has a long estimation process and also has high number of parameters which this property reduces the reliability of IDF curves. In the ...
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The intensity – duration – frequency (IDF) curves play most important role in the hydraulic design of structures. The traditional method to construct IDF curves has a long estimation process and also has high number of parameters which this property reduces the reliability of IDF curves. In the traditional method, rainfall in different durations should be available until the extraction of IDF curves are be possible. Whereas in many regions only 24-hour precipitation statistics are available which with this data the extraction of IDF curves using common methods are not possible. In this paper, fractal theory has been used to remove these problems and IDF curves are made with maximum annual daily rainfall data. The applied method in comparison with conventional method is less computational steps and its number of parameters is much lower that this property increases the reliability of IDF curves. Fractal and traditional methods were used to extract the IDF curves at Tangheie Panj rainfall station and the results shown that a fractal method with daily precipitation data clearly able to extract the IDF curves.
Research Article
S. Akhavan; M. Shabanpour; M. Esfahani
Abstract
In order to study the effect of soil compaction on root and shoot growth of wheat plants (Shahriar variety), a greenhouse pot experiment was conducted in Guilan University. The study design was factorial with completely randomized in three replications. Treatments included three compaction levels; (normal ...
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In order to study the effect of soil compaction on root and shoot growth of wheat plants (Shahriar variety), a greenhouse pot experiment was conducted in Guilan University. The study design was factorial with completely randomized in three replications. Treatments included three compaction levels; (normal compaction, compaction of ten percent and twenty percent) and two type of soil texture (clay and sand) will include 18 pots. Soil mechanical resistance index measured with the device influence the resistance gauge significant differences among treatments indicated. Root and shoot traits measured included plant fresh weight and total shoot dry weight, leaf dry weight (LDW), stem dry weight (SDW), root fresh weight (RFW), root dry weight (RDW), leaf area (LA), root area (RA), root volume (RV), root length (TL), root dry weight ratio of shoots, leaf area to root ratio (LA/RA), root length density (RLD), root surface area density (RSD), root mass density (RMD), dry root mass density (DRMD) and nitrogen content of roots, significant difference in the levels indicated treatments. The results showed that increasing the compaction of soil are affected characteristics related to the shoot and root of wheat plants, and twenty percent of the compaction (influence resistance 1200 KPa in the clay soil and 762.76 Kpa in the sandy soil) is limited roots and shoots growth than the natural soil.
Research Article
M. Jolaini; H.R. Mehrabadi
Abstract
Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today, process improvement, development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. So this study was conducted to determine ...
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Given the scarcity of water resources using modern methods of irrigation in agriculture will be inevitable. Today, process improvement, development and use of drip irrigation practices as one of the most advanced methods of irrigation in agriculture is increasing. So this study was conducted to determine the impacts of irrigation interval and drip irrigation method and their interactions on yield, water use efficiency and quality characteristic of cotton in Kashmar Agricultural Research Station, Khorasan Razavi Province. The study was carried out during 2006-2008. Experimental design was a completely randomized design with four replications. Treatments were included irrigation intervals (2, 4 and 6 day) and drip irrigation methods (surface and subsurface drip irrigation). The results showed that the irrigation methods had significant effect on Yield and Water Use efficiency (P≤ 0.01). There was significant difference between yield in surface and subsurface drip irrigation that was 3074 and 3988 kg/ha, respectively. Water use efficiency was 0.349 kg/m3 in subsurface drip irrigation that was greater than surface drip irrigation. The highest yield and water use efficiency in drip irrigation and subsurface irrigation 4 days, 4315 kg/ha and 0.375 kg/m3 respectively and the lowest with 2 days 3107 kg/ha and 0.265 kg/m3, respectively. Yields in irrigation intervals of 2, 4 and 6 days were 3491, 3725 and 3364 kg/ha, respectively, with no significance difference. The highest water use efficiency and yield were obtained in subsurface irrigation method with 4 days interval as 4315 kg/ha and 0.375 kg/m3 respectively, while the least water use efficiency and yield was obtained in surface irrigation method with 2 days interval as 3107 kg/ha and 0.265 kg/m3, respectively. Finally, using subsurface drip irrigation with irrigation every 4 days was chosen as the best treatment.
Research Article
Kh. Ghorbani
Abstract
So far several methods have been developed for mapping and interpolation of isohyets.one of the recently accepted methods is geographically weighting regression which is suitable for evaluation of spatial heterogeneity of dependent variable by using local regressions. In order to evaluate annually precipitation ...
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So far several methods have been developed for mapping and interpolation of isohyets.one of the recently accepted methods is geographically weighting regression which is suitable for evaluation of spatial heterogeneity of dependent variable by using local regressions. In order to evaluate annually precipitation spatial variation, this study was conducted in Gilan province which precipitation is distributed non-uniform due to different environmental conditions. The results of geographically weighting regression method were compared with another interpolation methods including global polynomial, local polynomial, inverse distance weighting (IDW), spiline, kriging and co-kriging and . In this study, average of 20 years annually precipitation data of 185 meteorological observations over Gilan Province and its neighboring stations was used for modeling of spatial distribution variations of mean annual precipitation by using other variables like elevation and position of points to the sea level. Cross validation technique was used to assessment accuracy of each interpolation methods. The result showed that geographically weighting regression method had minimum error with RMSE=147 and had significant difference with the kriging method which was in the second rank with RMSE=187. Finally the best method for mapping isohyets in Gilan province is geographically weighting regression method.
Research Article
S. Tajik; Sh. Ayoubi; F. Nourbakhash
Abstract
Enzymes are so crucial in the mineralization process of organic material. Information of the soil enzymes activity is used in determining of the soil microbial properties and they are also important in soil health and quality. Topographic attributes, soil properties and soil enzymes are associated together. ...
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Enzymes are so crucial in the mineralization process of organic material. Information of the soil enzymes activity is used in determining of the soil microbial properties and they are also important in soil health and quality. Topographic attributes, soil properties and soil enzymes are associated together. Hence, it is essential to know how these parameters affect on the soil enzymes activity. This study has been implemented in hilly region of Semiroum district located at southern Isfahan province, to develop a regression model between soil enzymes activity and soil and topographic characteristics. Mean annual temperature and precipitation in the studied area is 10.6°C and 350 mm, respectively. Soil sampling was done in a systematic randomly manner from the 0-10 cm surface layer. Topographic attributes were calculated by the digital elevation model with 10×10 m spatial resolution. Soil properties were determined by laboratory analysis. Multiple regression models between these parameters and soil enzymes activity were established and then the predictive models were validated using 20% of data. Results indicated soil parameters explained 33-63% of total variability of soil enzymes activity in the studied site. Topographic attributes explained 14- 15 %, and a combination of soil and topographic characteristics could explain 33-67% of total variability of soil enzymes activity. Therefore, the use of a combined data set of soil properties and topographic attributes could provide the powerful models for predicting of soil enzymes activity. These results confirmed that soil enzyme activity in the studied area is influenced by soil and topographic attributes synchronously. The results of validation ascertained that the predictors were unbiased and sufficiently accurate.
Research Article
J. Rahimi; A. Khalili; J. Bazrafshan
Abstract
The estimation of effective rainfall is an important technique for exploiting the rainwater resource, planning for irrigation in irrigated agriculture, and determining changes in dryland wheat products for country's macroeconomic management. In this research, a two-layer soil-water balance model based ...
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The estimation of effective rainfall is an important technique for exploiting the rainwater resource, planning for irrigation in irrigated agriculture, and determining changes in dryland wheat products for country's macroeconomic management. In this research, a two-layer soil-water balance model based on a new approach has been formulated to estimate the effective rainfall in dryland wheat crop. In this model, it is assumed that, in addition to the soil moisture retained on root zone on before day, also that part of water saved between the previous and current root-zone development add to the effective rainfall at current day. Greater ability of current approach to determine changes in wheat yields, which can be justified by changes in effective rainfall, confirms superiority of the current approach. Besides that, In order to estimate the effective rainfall in dryland wheat crop by this approach, daily climatic records during statistical period (1999-2000 till 2008-2009) from 12 meteorological stations of Fars province were collected. Results indicated that among the studied stations the amount of mean annual effective rainfall in dryland wheat crop changes from 296.4 (mm) in Doroodzan dam station to 112.6 (mm) in Abadeh station. Also, it is assumed that production of dryland wheat crop at north and northwest of Fars province is more success than other parts, due to satisfactory supply of effective rainfall.
