Research Article
A. Soleymani; M. Moradi; L. Naranjani
Abstract
Abstract
To evaluate the effects of the irrigation termination in different growth stages on yield and its components of autumn’s canola cultivars in Isfahan region. An experiment was conducted in 2005-2006 in Kabotar Abad Research Station. A split plot layout within a randomized complete block design ...
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Abstract
To evaluate the effects of the irrigation termination in different growth stages on yield and its components of autumn’s canola cultivars in Isfahan region. An experiment was conducted in 2005-2006 in Kabotar Abad Research Station. A split plot layout within a randomized complete block design with tree replication was used. Main plots were seven level of the irrigation cut-off time (D1:control irrigation or irrigation after 80 millimeter vaporize from class A basin to physiological maturity, D2: the irrigation cut-off time from stem elongation stage and then on , D3:the irrigation cut-off time from flowering stage and then on, D4: the irrigation cut-off time from pod stage and then on, D5: the irrigation cut-off time in stem elongation and flowering stages, D6: the irrigation cut-off time in stem elongation and pod stages, D7: the irrigation cut-off time in flowering and pod stages) and Sub plot were two canola cultivar(Zarfam and Okapi) great autumn’s product. The results showed that the effect of the irrigation cut-off time treatments on plant height, number of pod per plant, number of grain in pod, thousand grains weight, grain and oil yield were significant. After Control irrigation treatment, maximum grain yield and oil yield were obtained by D5, D6 and D7 treatments respectively but there is significant between these treatment and other treatments. Minimum grain and oil yield were produced by the irrigation cut-off time from stem elongation stage treatment. Zarfam was significant as compared to Okapi superior for plant height, number of pod per plant, thousand grains weight, oil percentage and oil yield. On the basis of the results obtained, D5, D6 and D7 treatments and Zarfam cultivar might be suitable for obtained maximum grain and oil yield under the irrigation cut-off time condition to the present study.
Keywords: Irrigation termination, Water stress, Grain yield and its components, Autumn's canola
Research Article
M. Zahedifar; N. Karimian; A.M. Ronaghi; J. Yasrebi; Y. Emam
Abstract
Abstract
In order to determine the time of maximum demand of winter wheat (Triticum aestivum L.) to phosphorous fertilizers and P and zinc (Zn) distribution in different parts of wheat at various growth stages and study their relation to the contents of these elements in soil P and Zn under field conditions, ...
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Abstract
In order to determine the time of maximum demand of winter wheat (Triticum aestivum L.) to phosphorous fertilizers and P and zinc (Zn) distribution in different parts of wheat at various growth stages and study their relation to the contents of these elements in soil P and Zn under field conditions, samples were collected from different parts of the plants at seven growth stages (i.e., the end of tillering to the complete seed ripening) and analyzed for P and Zn. Soil under the plants were also sampled, simultaneously, and analyzed for the same nutrients. The experimental plots consisted of three 5-ha fields located at Bajgah Experiment Station, College of Agriculture, Shiraz University, Shiraz, Iran (52 32 E, 29 36 N, 1810 m above mean sea level). Samples were taken during 2007-2008. Shoot P and Zn concentrations decreased as the growth proceeded from the end of tillering to the complete seed ripening stage. Phosphorus and Zn concentrations of flag leaf and stem increased from milk development toward complete seed ripening (stages 7 to 9), whereas those of spickle increased. Certain relation between soil and plant P or Zn was not found in the present study. The similarity of the P and Zn changes in flag leaf and stem suggests that flag leaf concentration of P and Zn (i.e., an almost non destructive analysis) can be used for evaluation of nutritional status of winter wheat plants under the field conditions.
Keywords: Flag leaf analysis, Wheat growth stages, Zadoks decimal codes, Spickle analysis
Research Article
M.H. Ravanbakhsh; A. Fotovat; Gh.H. Haghnia
Abstract
Abstract
A study was conducted to evaluate the effect of incubation time, sewage sludge and clay content on the distribution of nickel and cadmium in different fractions of selected calcareous soils. To meet this purpose, an experiment with two different soils (4 and 30 percent CaCO3), two different ...
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Abstract
A study was conducted to evaluate the effect of incubation time, sewage sludge and clay content on the distribution of nickel and cadmium in different fractions of selected calcareous soils. To meet this purpose, an experiment with two different soils (4 and 30 percent CaCO3), two different textures (8 and 40 percent clay), two levels of nickel (0 and 100 mg.kg-1), two levels of cadmium (0 and 25 mg.kg-1) and organic matter in the form of sewage sludge in two levels (0 and 50 t ha-1) was carried out. Two incubation times (0 and 60 days) and three replications in a completely randomized design were mentioned. The samples were incubated for two months at temperature of 25±2 °C and soil moisture condition close to field capacity. Distribution of Cd and Ni in fractions soluble+exchangeable, organically bound, carbonate bound and residual fractions was determined by a sequential extraction method. The results illustrated that, in both soils, residual form of Ni and carbonate form of Cd were dominant and showed a significant change with sewage sludge treatment and time. Sewage sludge application increased the amount of organic and carbonate bound of Ni and Cd significantly. The proportion of organic and carbonate bond Cd and Ni was higher in soil with 33 percent lime. In contrast, in soil with 4 percent lime, the percentage of Ni and Cd in the residual fractions was higher. Residual fraction of Ni and Cd in Clay soil was significantly higher than sandy loam soil. Increasing the amount of Ni and Cd increased all fractions of these metals significantly. The organic forms of Ni and Cd decreased significantly in the course of time. In general, based on the results, it may be concluded that calcium carbonate, clay percent and sewage sludge treatment play a key role in the distribution of Ni and Cd in different fractions of soils.
Keywords: Fractionation, Calcium carbonate, Sewage sludge, Clay percent, Time
Research Article
B. Ghahraman; M. Sadeghi; J. Mohammadi
Abstract
Abstract
Spatial variability of soils makes difficult analysis of soil water flow phenomena especially in a large area such as a watershed. Using scaling methods is a solution in variability problems. The objective of this study was to investigate the effect of the non-linear variability on performance ...
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Abstract
Spatial variability of soils makes difficult analysis of soil water flow phenomena especially in a large area such as a watershed. Using scaling methods is a solution in variability problems. The objective of this study was to investigate the effect of the non-linear variability on performance of the scaling methods of Richards’ equation for modeling infiltration in a watershed. The method of Warrick et al. by adopting van Genuchten hydraulic functions was used and variability of n values (power of van Genuchten hydraulic functions) was considered as the nonlinear variability. Marghmalek watershed, a sub watershed of Zayanderoud, with 97 Sq. kilometers was studied. In addition, ten virtual watersheds with various degrees of variability of n were evaluated which were generated by stochastic method of Monte Carlo. Using HYDRUS-1D model, original and scaled Richards’ equations were solved for infiltration condition with constant hydraulic head and uniform initial soil water content. The results indicated that coefficient of variations of n values in the Marghmalek watershed (equal to 2.57%) is small enough that the scaling method can be used efficiently in modeling infiltration. Therefore, in this watershed, generalized solutions of Richards’ equation can be adequately used instead of individual solutions for every points of the watershed. Evaluations in the virtual watersheds indicated that variability of n values considerably affect the error between the generalized and individual solutions. Based on the result of this study, it can be concluded that scaling methods of Richards’ equation can be adequately applied in the watersheds in which coefficient of variations of n values does not exceed 3%.
Keywords: Scaling, Richards’ equation, Infiltration, Nonlinear variability, Marghmalek watershed
Research Article
Z. Shirmohammadi; H. Ansari; A. Alizadeh
Abstract
Abstract
Potential evapotranspiration is one of basic parameter in hydrologic cycle that should be estimate in irrigation design and scheduling, watershed hydrology studies. Many applications in diverse disciplines require estimates of evapotranspiration (ET) at hourly or smaller time steps. The ...
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Abstract
Potential evapotranspiration is one of basic parameter in hydrologic cycle that should be estimate in irrigation design and scheduling, watershed hydrology studies. Many applications in diverse disciplines require estimates of evapotranspiration (ET) at hourly or smaller time steps. The primary objectives of this study were to compare the American Society of Civil Engineers (ASCE) and FAO-56 Penman–Monteith equations for hourly ET0 (ET0,hourly,ASCE and ET0, hourly,FAO) estimations for semiarid climate conditions and to compare the 24 h sum of ASCE (ET0,24 h,ASCE) and FAO-56 hourly ET0 (ET0,24 h,FAO) with the daily ET0 (ET0,d,FAO) computed from the daily FAO-56 equation, which is identical to ASCE daily ET0 equation. 278-days, i.e., 2008–2009 continuous hourly and daily weather data from the automated internet weather station where placed in private Farm in fariman khorasan razavi province were used. It was evident that during the day, ET0,hourly,ASCE was higher than ET0, hourly ,FAO due to a lower surface resistance parameter value, while at night ET0, hourly,ASCE was lower than ET0, hourly,FAO due to a higher surface resistance parameter value. The ET0, hourly,FAO was about 18% less than ET0, hourly,ASCE and ET0,24 h,FAO was about 14% lower than ET0,24 h,ASCE. The difference between ET0, hourly,ASCE and ET0, hourly,FAO during the day and night was highly dependent on wind speed. For the entire year, ET0,24 h,FAO was 2.6% higher than ET0,d,FAO while ET0,24 h,ASCE was 17% higher than ET0,d,FAO. These results demonstrated that for applications that require hourly time steps or daily ET0 for the entire year, the use of ET0, hourly ,FAO and ET0,24 h,FAO, respectively, will yield more consistent outcomes.
Keywords: Reference evapotranspiration, Surface resistance, ASCE penman-monteith, FAO-56Penman-Monteith, Summation of hourly, Fariman
Research Article
M. Mahmoudi; R. Rahnemaie; A. Eshaghi; M.J. Malakouti; M. Jalali
Abstract
Abstract
Herbicides are the main sources of soil and water pollution in paddy fields. Herbicides mobility to the surface and ground water is a major concern for human health and the environment. It is, therefore, necessary to investigate their fate and their interactions in natural ecosystems. To meet ...
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Abstract
Herbicides are the main sources of soil and water pollution in paddy fields. Herbicides mobility to the surface and ground water is a major concern for human health and the environment. It is, therefore, necessary to investigate their fate and their interactions in natural ecosystems. To meet this purpose, field experiments were conducted to measure kinetic of thiobencarb dissipation in soil and water at Dashtnaz and Gharakhail agricultural research stations, Mazandaran. Also, its adsorption and desorption isotherms were determined in the soil samples. Thiobencarb concentration was monitored in soil and water (soil solution) via sampling during 315 and 60 days periods, respectively. Adsorption isotherms were carried out in equilibrium concentration ranged from 0 to 26 mg L-1. Desorption isotherms were measured in three equilibrium concentrations. The results of field experiments revealed that thiobencarb concentration is declined with time rapidly and reaches to a steady state after approximately 30 days. Experimental data were successfully described using the first order kinetics equation. Thiobencarb half-lives were determined 7 and 10 days in Dashtnaz and Gharakhail water, respectively. In both soils, thiobencarb concentration was strongly varied in early stages of soil sampling. The variations were reduced with discontinuation of irrigation. Similar to water, thiobencarb concentration in soils was gradually decreased with time, and arrived to a relatively constant concentration after about 110 days. First order kinetic equation described correctly the change in thiobencarb dissipation in soils. Thiobencarb half-lives were calculated 93 and 114 days for Dashtnaz and Gharakhail soils, respectively. Adsorption isotherms indicated that thiobencarb is strongly adsorbed on soil particles. Thiobencarb was desorbed very slowly and a strong hysteresis was observed between adsorption and desorption isotherms. Calculations revealed that thiobencarb is a persistence and non-leacher herbicide in the soil, due to its strong adsorption and high hydrophobic coefficient.
Keywords: Water and soil pollution, Thiobencarb, Degradation, Adsorption and desorption isotherms
Research Article
R. Daempanah; Gh.H. Haghnia; A. Alizadeh; A.R. Karimi
Abstract
Abstract
In the recent decades, application of geostatistic and remote sensing for mapping salinity and sodicity of surface soil and monitoring it's changes have been developed. The goal of this research was to compare the capability of geostatistic and remote sensing methods for mapping salinity-sodicity ...
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Abstract
In the recent decades, application of geostatistic and remote sensing for mapping salinity and sodicity of surface soil and monitoring it's changes have been developed. The goal of this research was to compare the capability of geostatistic and remote sensing methods for mapping salinity-sodicity of soils in playa from sourthern Mah Valat county, in the Khorasan Razavi province. 88 samples of surface soil from depth of 0 to 10cm on the crossing lines of 1000×1000 meter grids were taken, and their EC, PH and SAR were measured. After normalizing variables, checking anisotropy and determining the parameters of variogram, the salinity and sodicity maps of soil were prepared using kriging method with an accuracy of 60 and 58 percent. the Results revealed that kriging had trimmed salinity and sodicity data because it had lowered the standard deviation. The IRS-P6 images were used to map salinity and sodicity maps. After pre-processing of images, PCA, salinity indexes of SI1, SI2, BI and NDSI were calculated and digital number of sampling points were extracted. By checking the correlation between variables and digital numbers of images, the SI1 that had the highest Pearson coefficient, was selected and salinity map of surface soil was prepared by the method of supervised classification. There was no correlation between images and sodicity data, and also between sodicity, salinity and pH data. Probability of extracting sodicity map by this method was evaluated poor. The result of this resarch also showed that for increasing accuracy in kriging maps more points should be taken, while in the remote sensing with less points while saving time and money, it’s possible to have more accurate maps.
Keywords: IRS, EC, Geostatistic, Salinity index, Superwised classification, Mah Valat
Research Article
Z. Naghizadeh Asl; E. Dordipour; A.L. Gholizadeh; F. Kiani; H. Emami
Abstract
Abstract
In order to assess the availability of phosphorous (P), different methods have been proposed in the last decades. The results of these methods in soils with various pH, calcium carbonate, organic matter, Al and Fe oxides and hydroxides and other properties especially in Iranian soils can not ...
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Abstract
In order to assess the availability of phosphorous (P), different methods have been proposed in the last decades. The results of these methods in soils with various pH, calcium carbonate, organic matter, Al and Fe oxides and hydroxides and other properties especially in Iranian soils can not be used. In addition, knowledge about transformation of P forms is necessary for perception of P behavior. The objective of this research was to study the relationship between P extracted by some extract ants and soil properties and, different forms of inorganic P. Therefore 20 soil samples were collected from 0-30 cm depth of Glosetan province soils. Soil P was extracted and measured by sodium bicarbonate at pH = 8.5 (NaHCO3), DTPA- Ammonium bicarbonate (NH4HCO3-DTPA), DTPA- Sodium bicarbonate (NaHCO3-DTPA), and 0.01 M CaCl2. Also, different forms of inorganic P in the studied soils were measured by Jiang and Gu sequential fractionation method. The results showed that the amount of P extracted by different extract ants was in the order NaHCO3 > NaHCO3-DTPA > NH4HCO3-DTPA > CaCl2. There was a significant correlation between P extracted by different extract ants and determination coefficient between P extracted by NaHCO3 and NaHCO3-DTPA, NaHCO3 and NH4HCO3-DTPA, and NaHCO3-DTPA and NH4HCO3-DTPA were 0.91**, 0.85**, and 0.82** respectively. P extracted by NaHCO3, NH4HCO3-DTPA, and NaHCO3-DTPA with pH, EC, clay and Calcium carbonate percentage had a negative and significant correlation, but with Organic matter it was significant and positive. Also among the P forms only di, octa and Al oxides P had a significant correlation with P extracted by studied extract ants. In general the distribution of inorganic P forms in these soils was as below: Ca10-P > Al-P > Ca8-P > Fe-P > Ca2-P > Fe- Occluded-P. According to significant correlation between P extracted by studied extract ants with some P forms it seems that, some P forms can be transferred to available form of plants.
Keywords: P Extract ants, Sequential fractionation, Inorganic P forms
Research Article
J. Fallahzade; M.A. Hajabbasi
Abstract
Abstract
Soil organic matter and its components are important factors in formation and stability of aggregates and subsequently soil structure. However data regarding organic matter distribution in soil aggregates is scarce, particularly in arid soils of Central Iran. The objective of this study was ...
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Abstract
Soil organic matter and its components are important factors in formation and stability of aggregates and subsequently soil structure. However data regarding organic matter distribution in soil aggregates is scarce, particularly in arid soils of Central Iran. The objective of this study was to investigate the distribution of organic carbon (OC), total nitrogen (TN), and carbohydrates in aggregates of different size classes (2–4, 1–2, 0.5–1, 0.25–0.5, 0.05–0.25 and
Research Article
Sh Asghari
Abstract
Abstract
One of the methods for improving soil physical quality of arid and semiarid regions is the application of cheap organic conditioners such as sewage sludge. This research was conducted in large pots (50 cm diameter, 25 cm height) to study the effects of Tabriz petrochemical biological sludge ...
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Abstract
One of the methods for improving soil physical quality of arid and semiarid regions is the application of cheap organic conditioners such as sewage sludge. This research was conducted in large pots (50 cm diameter, 25 cm height) to study the effects of Tabriz petrochemical biological sludge at 4 rates (25, 50, 75 and 100 tons/ha) on organic carbon (OC), mean weight diameter (MWD) of aggregates, water-dispersible clay (WDC), liquid limit (LL) and plastic limit (PL) moistures and plasticity index (PI = LL – PL) during time in a semiarid soil. There was also control treatment (without sludge) and all treatments included 3 replications. Incubation of treatments was done in a greenhouse with field capacity moisture content of 0.7 – 0.8 and temperature of
22 ± 4 ˚C for 6 months. All parameters were measured at 60, 120 and 180 days. The experiment was conducted as factorial (5 used rates of sludge (factor A) and 3 incubation times (factor B)) with randomized completely blocks design. Results showed that all used sludge rates significantly (P < 0.01) increased OC and decreased WDC as compared with the control. Negative correlation (r = - 0.84*) between OC and WDC was significant (P < 0.05). Moistures of LL and PL significantly (P < 0.01) increased with sludge application only at the rates of 75 and 100 tons/ha. Significant and positive correlation (r = 0.99***, P < 0.001) was found between OC with LL and PL. The effect of sludge used rates on MWD and PI was not significant. Significant and negative correlation (r = - 0.92***, P < 0.1) was found between MWD and WDC at 3 incubation times. This research indicated that petrochemical sludge as a cheap organic conditioner improved physical quality of the semiarid soil.
Keywords: Sewage sludge, Semiarid soil, Organic carbon, Aggregate stability, Consistency limit
Research Article
S.H. Sanaei-Nejad; S. Noori; M. Hashemi nia
Abstract
Abstract
Evapotranspiration (ET) determination is a key factor for irrigation scheduling, water balance, irrigation system design and management and crop yields simulation. Therefore many scientists have tried to estimate evapotranspiration in different spatial and temporal scales. Remote sensing is ...
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Abstract
Evapotranspiration (ET) determination is a key factor for irrigation scheduling, water balance, irrigation system design and management and crop yields simulation. Therefore many scientists have tried to estimate evapotranspiration in different spatial and temporal scales. Remote sensing is a one of new technique in estimation of ET in regional scales. So, in this study it’s tried to estimate spatial distribution daily actual ET for Mashhad’s sub basin using MODIS image data related to 4th June, 1st July and 26th July 2009 and surface energy balance algorithm for land (SEBAL) taking into account topographic effects. The results showed that MODIS image data and SEBAL method were able to estimate actual daily ET in Mashhad sub-basin properly. Based on the results, areas which had dense vegetation and low temperatures had high ET rates, while in areas with sparse vegetation and high temperatures the ET rate was low.
Keywords: Evapotranspiration, MODIS, Remote sensing, SEBAL
Research Article
A. Beheshti Ale Agha; F. Raiesi; A. Golchin
Abstract
Abstract
In this study the effects of land use changes from pasturelands to croplands on soil microbiological and biochemical properties were studied in Kangaver, Dehno and Soltanye regions. Composite soil samples from 0-20 and 20-40 cm depths of pasture and cultivated lands were taken from Kangaver, ...
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Abstract
In this study the effects of land use changes from pasturelands to croplands on soil microbiological and biochemical properties were studied in Kangaver, Dehno and Soltanye regions. Composite soil samples from 0-20 and 20-40 cm depths of pasture and cultivated lands were taken from Kangaver, Dehno and Soltanye regions, and soil microbial respiration, microbial biomass C and N, and urease, alkaline phosphatase, saccharase and arylsulfatase activities were determined. Results showed that land use changes from pasture to arable lands resulted in a significant reduction of microbial respiration in Kangaver (36-64%), Dehno (45-60%) and Soltanye (34%) regions. Similarly, substrate-induced respiration (SIR) decreased between 13 to 37% due to land use changes in all the three regions studied. The microbial biomass C (30-60%), N (18-56%) and C/N ratios (9-17%) in the two soil depths of cultivated sites were lower than those of forest sites in the three regions while metabolic quotient (36-95%), the portion of carbon (4-60%) and nitrogen (3-76%) of microbial biomass in total soil and percentage mineralized C (36-95%) in all the three regions increased due to land use changes. The assay of enzyme activities showed that alkaline phosphatase in both soil depths did not change substantially for each region. In Soltanye region, urease activity decreased (18%) only in the 0-20 cm depth and land use effects were not significant for the other enzymes. Conversion of pastures to agricultural lands in Kangaver region resulted significant decreases in urease (20%), saccharase (33%) and arylsulfatase (11%) activities in the surface layer, but not in the 20-40 cm depth. In Dehno, increased urease and arylsulfatase activities in both soil depths due to land use changes from pastures to cultivated lands were significant, but increased saccharase activity was significant only in the 0-20 cm depth. Overall, it is concluded that a change in land use from pastures to croplands with widespread agricultural practices, specifically long-term intensive tillage activities, may lead to enhanced availability of oxygen and substrate to microorganisms, which could result in increased microbial activity including soil respiration.
Keywords: Land use change, Agricultural practices, Soil organic matter, Soil enzyme activity, Soil microbial respiration, Soil quality
Research Article
S.H. Sadrghaen; J. Baghani; S.A. Haghayeghi Moghaddam; M. Akbari
Abstract
Abstract
This study was conducted to determine the best drip irrigation method for pepper cultivation with the objective of water saving and obtaining maximum yield. The study was done during two years. Experimental design was randomized complete blocks design (RCBD) in split plot with four replications. ...
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Abstract
This study was conducted to determine the best drip irrigation method for pepper cultivation with the objective of water saving and obtaining maximum yield. The study was done during two years. Experimental design was randomized complete blocks design (RCBD) in split plot with four replications. Three different drip irrigation methods; drip irrigation with in-line emitter tubes, drip irrigation (tape), and drip irrigation with porous pipes as main plot and three different amount of water (50, 75 & 100% water requirement) were as sub-plot. The result in the first year showed that the effect of irrigation levels on the characteristics of plant except yield was no significant (α < 0.01), but the effect of irrigation methods on water use efficiency was significant (α < 0.05) .In the second year the effect of irrigation levels and irrigation methods on yield was significant (α < 0.05), but the effects of combination irrigation levels and methods on yield was not significant. The result in two years showed that the pepper is a sensitive plant to water deficit. The drip irrigation (tape) and 100% water requirement treatment had the highest yield and water use efficiency. The result also showed that the porous pipes had no good efficiency. According to the results, the best option for pepper is drip irrigation (tape) with using 100% water requirement.
Keywords: Drip irrigation, Pepper, Porous pipes, Tape irrigation, Water use efficiency
Research Article
L. Parviz; M. Kholghy; P. Irannejad; Sh. Araghinejad; Kh. Valizadeh
Abstract
Abstract
Land surface hydrological models has importance in the determination of soil moisture and temperature, the rate of evapotranspiration, stream flow by emphasis on the land surface physical and dynamic process descriptions. In this research, VIC land surface hydrological model has been used for ...
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Abstract
Land surface hydrological models has importance in the determination of soil moisture and temperature, the rate of evapotranspiration, stream flow by emphasis on the land surface physical and dynamic process descriptions. In this research, VIC land surface hydrological model has been used for the land surface temperature and stream flow determination. The VIC runoff simulation in each cell is based on both the infiltration excess and saturation runoff. Also for within-grid and between-grids routing, VIC model was coupled to the routing model. For running VIC model, Sefidroad River basin based on DEM of basin was divided in to 18 cells with 57 km resolution. The comparison of observed and simulated stream flow in the outlet of basin hydrometery station, indicated that Nash coefficient increased by using the inverse distance method that is corrected to the height for using interpolation of meteorological variables in each cell. The land surface temperature estimation in the energy mode of VIC model has accurate results than the water mode. The VIC model in the runoff simulation is more sensitive to the infiltration shape parameter. The infiltration shape parameter is effective in the surface and subsurface runoff simulation but the high influence of this parameter is related to the surface runoff. Ws and Ds play an important role in the subsurface runoff simulation. Comparison between observed and simulated stream flow using calibrated parameters in some of hydrometery stations indicated the ability of model in stream flow simulation.
Keywords: Land surface hydrological model, VIC model, Sefidroad River basin, Infiltration shape parameter
Research Article
S.H.R. Sadeghi; M.S. Zarif Moazam; Kh. Mirnia
Abstract
Abstract
The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic ...
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Abstract
The proper management of a watershed depends on recognition of effective elements and investigation of their behavior in different conditions. Till date, many researches have studied the role of topographical general characteristics on hydrologic behaviors. Whereas, the changeability of hydrologic properties under different conditions, especially in Iranian watershed has been rarely taken into account. This research aimed to assess the role of slope steepness and aspect on runoff and sediment characteristics in Educational and Research Watershed of Tarbiat Modares University (Kojour) watershed located in southeastern of Nowshahr Township, Iran. Experiments were conducted by using a pressure rain simulator with an intensity of 1.6 mm min-1 and a plot in dimension of 30×30 cm in two slope ranges i.e. ≤ 25 and > 25% and eastern and western aspects. These experiments were done in three replications and in particular places on monthly basis from October 2008 to June 2009. The study was formulated in factorial and Latin square designs and the associated results were then analyzed with the help of SPSS 17 software package. Results showed that the affect of slope on runoff volume was significant (p
Research Article
T. Honar; A. Sabet Sarvestani; A.A. Kamgar Haghighi; Sh. Shams
Abstract
Abstract
The propose of this study was evaluation of CropSyst Model on growth simulation and yield stimation of canola under different irrigation treatments. Canola (Talaye) was sown under 5 treatment and 4 replicants in completed randomized block designs at the college of Agriculture, Shiraz Universityduring ...
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Abstract
The propose of this study was evaluation of CropSyst Model on growth simulation and yield stimation of canola under different irrigation treatments. Canola (Talaye) was sown under 5 treatment and 4 replicants in completed randomized block designs at the college of Agriculture, Shiraz Universityduring 2007-2008. During the growth season dry mass and LAI was meseaured frequently, then model was calibrated by the resukts. Obtained results showed very good esyimation by the simulation model, as the correlation coefficient square between dry mass and LAI in defferent treatments were more than 0.99 and 0.95, respectively. Also correlation coeficient between meseaured and simulated crop yeild was 0.96, that shows the accuracy of model in simulation on crop parameter. Also the model was valuated by independent data. Obtained results showed the accuracy of model simulation in dry matter as the correlation cofficient was achieved 0.9. Also LAI simulation in all treatments had good reults, as generaly is reliable in canola investigations.
Keywords: Simiulatinng models, Alfalfa, Leaf area index
Research Article
M. Movahedan; N. Abbasi; M. Keramati
Abstract
Abstract
Wind erosion of soils and suspended particles in Iran is one of the serious environmental and agricultural problems which affect agricultural lands, water reservoirs, irrigation canals, drains and etc. Therefore wind erosion control needs attention specially in arid and semi-arid regions. Although ...
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Abstract
Wind erosion of soils and suspended particles in Iran is one of the serious environmental and agricultural problems which affect agricultural lands, water reservoirs, irrigation canals, drains and etc. Therefore wind erosion control needs attention specially in arid and semi-arid regions. Although in recent years, some polymeric materials have been used for improvement of structural stability, increasing aggregate stability and soil stabilization, but still some important parameters such as kind of polymer, quantity of polymer, efficiency against wind and water erosion, durability in field conditions and environmental impacts should be considered. In this research, Polyvinyl Acetate-based polymer was used for three different soil textures against wind erosion. Then the effect of this polymer on wind erosion control was investigated and its results were compared with water treated soil samples. The results of wind tunnel with a maximum 26 m/s wind velocity showed that there was a significant difference between the erosion of polymer treated and water treated samples and with application of 25 gr/m2 Polyvinyl Acetate, the erosion of Aeolian sands samples reduced to zero in the experimental conditions in relation to water treated samples. For silty and clayey soils treated by polymer, the wind erosion reduced minimum 90% in relation to water treated samples.
Keywords: Polyvinyl Acetate, Wind erosion, Wind tunnel
Research Article
S. Zarrinfar; B. Ghahraman; K. Davary
Abstract
Abstract
Saturated hydraulic conductivity (Ks) is one of the most important physical properties of soils which is expensive and time-consuming to directly measure. Hence, indirect methods, such as pedotransfer functions (PTFs), were developed to predict the Ks. Previous studies showed that most of the ...
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Abstract
Saturated hydraulic conductivity (Ks) is one of the most important physical properties of soils which is expensive and time-consuming to directly measure. Hence, indirect methods, such as pedotransfer functions (PTFs), were developed to predict the Ks. Previous studies showed that most of the PTFs common in the literature can not suitably predict the Ks. Hence, this study was conducted to develop some new PTFs. In this study, some physical properties of 49 gravel soils, including Ks, bulk density and particle size distribution, were measured in a land in the campus of ferdowsi university of mashhad. The measurements were performed in a regular quadrangular grid with 4 meters distances. To measure the Ks, inverse hole method was used. To derive some PTFs, 8 arbitrary sets of independent variables were selected. For each set, the best subset of independent variables was selected using best subset regression method. Then, this PTF was found using partial least square regression method. To evaluate the validity of the derived PTFs, we used cross-validation method. The results showed that the PTF that used d50, geometric mean and standard deviation of the particle size distribution as independent variables could more precisely predict the Ks. For this PTF, R2, RMSE, MAE and R2pred are 0.4, 0.245, 0208 and 0.3 respectively.
Keywords: Pedotransfer function, Saturated hydraulic conductivity, Gravel soils, Inverse hole
Research Article
F.S. Hosseini; A. Nezami; M. Parsa; K. Hajmohammadnia
Abstract
Abstract
Supplementary irrigation for suitable crops production in most area of Iran is necessary. In order to study supplementary irrigation effects on yield and yield components of three Lentil (Lens culinaris Medik.) cultivars, an experiment was carried out as split block based on randomized complete ...
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Abstract
Supplementary irrigation for suitable crops production in most area of Iran is necessary. In order to study supplementary irrigation effects on yield and yield components of three Lentil (Lens culinaris Medik.) cultivars, an experiment was carried out as split block based on randomized complete block design with three replications at Research Field, College of Agriculture, Ferdowsi University of Mashhad. In this study, irrigation treatments (including irrigation in all phenological stages; irrigation in branching, flowering, podding and seed setting stage, and without any irrigation in the growing period) as main plot, and three lentil cultivars (Robat, Kalpoosh and Gachsaran) as sub plot were adjusted. Results showed that irrigation had significant effects on number of pods per plant, 100 seed weight, grain and biological yield. Maximum of these traits (except 100 seed weight) after complete irrigation treatment, was obtained at supplementary irrigation in flowering stage. Supplementary irrigation in podding and seed setting stages increased 100 seed weight as compared to irrigation in flowering stage. In without-irrigation treatment, the Gachsaran cultivar produced maximum grain yield. Irrigation in flowering stage increased yield of Robat, Kalpoosh and Gachsaran cultivars more than 60, 60 and 39% relative to the without-irrigation treatment, respectively. Based on the results, supplementary irrigation in flowering stage was more effective in increasing number of pods per plant and lentil yield.
Keywords: Irrigation, Grain yield, Biological yield, Lentil
Research Article
E. Nabizadeh; H. Beigi Harchegani
Abstract
Abstract
Water retention curve (WRC) is a fundamental property of soil. It is used to evaluate available water, permeability, drainage and movement of solutes. Despite numerous studies on WRC of soils abroad, no local study has been carried out on Charmahal-va-Bakhtiari soils. The objective of this ...
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Abstract
Water retention curve (WRC) is a fundamental property of soil. It is used to evaluate available water, permeability, drainage and movement of solutes. Despite numerous studies on WRC of soils abroad, no local study has been carried out on Charmahal-va-Bakhtiari soils. The objective of this study was to compare the quality of fitting of several WRC models to Lordegan soils and to select the appropriate models. The studied models were: Brooks-Corey, van Genuchten, Farrel-Larson, Libardi et al., Simmons et al., Bruce-Luxmoore and Campbell. Fifty soil samples were collected from across Lordegan plain and Their texture were determined characterized for texture. Water retention data were obtained using hanging water column and pressure plate apparatus. Models were fitted using SWRC 3.0 software. R-square ( ) and were used for evaluating fitting quality. All models did well with ranging from 0.90 to 1.00 and from 0.001 to 0.036. However, in all samples and all textural classes, van Genuchten model fitted best. Brooks-Corey model was the weakest although its was always greater than 0.90 and its maximum was 0.036 . Therefor, van Genuchten model is recommended for soils of Lordegan plain.
Keywords: Soil water retention curve, Van-Genuchten, Brooks-Corey, Fitting quality
Research Article
M.H. Nouri Gheidari; M. Abdesharif Esfahanirif Esf; L. Ebrahimi
Abstract
Abstract
Given the importance of environmental cycles had led to allocation of water-right for water species and ecosystems which is known as environmental flow or in stream flow. From among the various methods for estimating environmental flow, building block approach is considered as a very powerful ...
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Abstract
Given the importance of environmental cycles had led to allocation of water-right for water species and ecosystems which is known as environmental flow or in stream flow. From among the various methods for estimating environmental flow, building block approach is considered as a very powerful tool for estimating the water needs. In this paper, beside simplifying the building block approach and with regard to water flow properties of Gamber River in West Azerbaijan Province, we attempt to revise and localize this method. The results revealed that in this method, unlike the previous ones, instead of considering a constant index for environmental flows, we can quantify environmentally daily and monthly time series. In so-called method, environmental flows in various management classes were closer to Tnant normal values and in classes of A, B, and C, they were higher than environmental flows in more wetted perimeter method.
Keywords: Environmental flow, Aquatic ecosystems, Gumbar River, Building Block Method
Research Article
A.R. Koocheki; V. Mokhtari; Sh. Taherabadi; S. Kalantari
Abstract
Abstract
In order to investigate the response of two species of P. ovata and P. psyllium to water deficit. The experiment was conducted during 2009 growing seasons in the Agriculture research Station Ferdowsi of Mashhad. For this purpose a split plot experiment based on complete randomized block design ...
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Abstract
In order to investigate the response of two species of P. ovata and P. psyllium to water deficit. The experiment was conducted during 2009 growing seasons in the Agriculture research Station Ferdowsi of Mashhad. For this purpose a split plot experiment based on complete randomized block design with three replications was used. Four irrigation levels (4000, 3000, 2000, 1000 m3/ha) allocated in the main plots and two species of plantago (p. ovate, p. psyillium) were as sub plots. Criteria such as spike length, number of spikes per plant, number of seeds per spike, 1000-seed weight, straw and seed yield were measured accordingly. Three quality characters namely amount of mucilage, swelling factor and swelling rate per gram mucilage were also measured. The results indicated that number of spikes per plant, number of seeds per spike, 1000-seed weight, seed yield were significantly affected by irrigation levels. The maximum value of spike length, number of spikes per plant, number of seeds per spike, 1000-seed weight was obtained in irrigation level of 4000 (m3/ha), and the maximum value of straw and seed yield in p. ovatea was obtained in irrigation levels of 4000 (m3/ha) and 3000 (m3/ha), respectively and to p. psyllium was obtained in irrigation level of 3000 (m3/ha) and 4000 (m3/ha), respectively. The maximum amount of mucilage and swelling factor were obtained for both species were obtained irrigation level of 2000(m3/ha) and the maximum swelling rate per gram mucilage for both species were obtained irrigation level of 1000 (m3/ha).
Keywords: Water deficit, Yield, yield components, P. ovate, p. psyllium, Mucilage
Research Article
M. Mousavi baygi; B. Ashraf
Abstract
Abstract
Nowadays, solar energy as one of the most important sources of clean and free of damaging environmental effects energy are used in many cases including generation of electricity, heat and desalination of salt water. The purpose of this research is identification of high radiation areas as most ...
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Abstract
Nowadays, solar energy as one of the most important sources of clean and free of damaging environmental effects energy are used in many cases including generation of electricity, heat and desalination of salt water. The purpose of this research is identification of high radiation areas as most suitable regions for these applications.To do this, cloudiness data of 120 synoptic stations were used to find the number of days with 0-2/8 cloudiness and calculate the average of monthly, seasonal and the annual of them over a period of 20 years (1989-2008). The statistical software of SPSS 16 was used to find the correlation equations of locations (latitude and altitude) with a mean seasonal (with R2 equal 0.81, 0.82 and 0.84 for spring, autumn and winter respectively) and annual number (with R2 equal 0.78) of days with low cloudiness. Finally by the method of interpolation Spline has been produced zoning maps of seasonal and annual high radiation areas of country. The investigation of average monthly amounts indicated that the most sunny days in April belonged to the BAFT, in May belonged to JASK, in June belonged MINAB, in July belonged to DEHLORAN, in August belonged MAHSHAHR, in September belonged BUSHEHR, in October belonged to KENARAK, in November and December belonged to CHABAHAR, in January and February belonged to SARAVAN and in March belonged to CHABAHAR. Also in seasonal scale the cities of KAHNUJ, AGHAJARI and CHABAHAR in spring, summer, and autumn & winter respectively were most high radiation regions of country during this period. The study also found that 89 stations of 120 stations that studied, over 1989- 2008 in more than 200 days of 365 days on the year (more than 55 percent on the year), had clear and sunny sky and therefore most areas of Iran have great ability to use renewable solar energy.
Keywords: Cloudiness, Solar radiation, Mapping, Spline interpolation method, Synoptic station
Research Article
R. Badizadegan; K. Esmaili; M. Faghfour Maghrebi; M. Saneie
Abstract
Abstract
One of the most frequently encountered cases of rapid varied flow is the hydraulic jump. It occurs when a supercritical open channel flow changes into sub critical flow. In the present research, the experimental study of the hydraulic jump on seven sinusoidal corrugated beds with different ...
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Abstract
One of the most frequently encountered cases of rapid varied flow is the hydraulic jump. It occurs when a supercritical open channel flow changes into sub critical flow. In the present research, the experimental study of the hydraulic jump on seven sinusoidal corrugated beds with different wave steepness. The wave steepness of sinusoidal corrugated beds is in the range of 0.1667 to 0.75 and Froude number was in the range of 4.5 to 12.26. The results showed that the tail water depth of a jump on a corrugated bed is about 20% smaller than that on smooth bed in Froude number 12 and the length of jump on corrugated beds is about 35% less than that for smooth bed.
Keywords: Hydraulic jump, Corrugated bed, Wave steepness
Research Article
A. Farzane; S.H. Nemati; N. Vahdati
Abstract
Abstract
Today, greenhouses are used for controlling different climacterics parameters, specially light and temperatures on agricultural productions. the most part of productions is Vegetables production in traditional greenhouses (TG) and unfortunately productions quality and quantity in greenhouses ...
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Abstract
Today, greenhouses are used for controlling different climacterics parameters, specially light and temperatures on agricultural productions. the most part of productions is Vegetables production in traditional greenhouses (TG) and unfortunately productions quality and quantity in greenhouses is lower than modern (MG) ones. this experiment studies the effects of different climates of two kinds of greenhouses; MG (temperature: 21/93 oc, light density: 5916 fc, relative humidity:31%) and TG (temperature: 32/72 oc, light density:4650 fc, relative humidity: 45%) greenhouses on the growth of tomato cultivars. The examine was installed in Factorial Completely Randomized Plots Design with three replications and two kinds of greenhouses (TG and MG) and four tomato cultivars that were done in MG and TG of Horticulture department of Ferdowsi university in Mashhad. The results showed; Titrable acidity and pH were affected by cultivars and greenhouses, and showed the significant differences. The Effects of greenhouse climacteric on vitamin C content become signified (p≤%5). The highest number of shoots, inflorescences and fruits (59.7, 14.1 and 27.8) were observed in MG. Isn MG, yield increased up to 70 percent and was more than TG, increasing in number of fertile flowers and fruit sets led to increasing of yield in MG and also cultivars, greenhouse climacteric parameters and their interactions had significant effects on mass of 1000 grain and the seed, which was produced in MG (3.53 g), were bigger than the TG (3.20 g). So we observed that Chlorophyll content of leaf in MG, which is directly related to photosynthesis and yield, was more than the TG.
Keywords: Traditional greenhouse, Modern greenhouse, Yield, Quantitative, Qualitative characteristics
