Showing 9 results for Oustan
B Dolati, Sh Oustan, A Samadi,
Volume 12, Issue 46 (1-2009)
Abstract
Successive cropping of potassium-demanding crops like sunflower leads to depletion of soil potassium (K). This study was conducted to investigate the different forms of K and quantity–intensity (Q/I) relationship for sunflower growing soils in Khoy region, West Azarbaijan province. Twenty composite soil samples were collected from different soil series. Different forms of K, including solution K (Kso), exchangeable K (Kex) and non-exchangeable K (Knex) were determined. The results showed that Kso values varied from 0.061 to 0.54 (mmol L-1), with an average of 0.28 (mmol L-1), Kav values ranged from 55 to 699 (mg kg-1), 265 mg Kg-1 on average, and Kex values ranged from 54 to 694 (mg Kg-1) with an average of 261 (mg kg-1). Furthermore, Knex values varied from 160 to 612 (mg kg-1), 261 (mg kg-1) on average. Available K (NH4OAc- extraction) was less than 250 mg Kg-1 in half of the soils indicating the depletion of potassium from these soils. The Q/I curves were predominantly located in the adsorption regions. The Q/I curves were linear and lacked the curvature part relating to loss and gain of potassium present in the specific sites. The PBCK values varied from 11 to 108 (cmolc kg-1)/ (mol L-1) 0.5 and an average of 38 (cmolc kg-1)/(mol L-1)0.5. There was a linear significant relationship between PBCK and CEC (r2=0.82***). The AReK values ranged from 0.0014 to 0.027 (mol L-1) 0.5 and 0.0076 (mol L-1)0.5 on average. There was a significant relationship between the values of AReK and those of the soil solution K (r=0.68**). The Ko values varied from 0.0050 to 0.49 cmolc kg-1and an average of 0.21cmolc kg-1. Additionally, there was a high significant relationship between the values of Ko and ARoK (r= 0.95***) in the soils under study.
M Khorshid, As Hosseinpur, Sh Oustan,
Volume 12, Issue 46 (1-2009)
Abstract
Organic manures can affect phosphorus (P) sorption characteristics (PSC) and its availability in soils. Information about effect of sewage sludge (SL) on PSC in calcareous soils of Hamadan province is limited. The objective of this research was to study the effect of SL on PSC and available P in 10 calcareous soils. The soil samples were incubated with and without 1.5 % SL for 5 months at field capacity at 25 ±1 סC . After incubation, available P was determined by Olsen method. Furthermore, 2.5 g samples were shaken with 25 mL 0.01 M CaCl2 containing 0 to 30 mg P L-1 as KH2PO4. After equilibration, suspensions were centrifuged and P concentration was determined in clear extracts. The results showed that SL application increased available P. The mean available P value increased by 37.6 %. Available P in untreated and SL-treated soils ranged from 8.1 to 22.1 and 14.8 to 28.0 mg kg-1, respectively. Sorption data in the all samples were well described by Freundlich and linear isotherm, whereas sorption data in all SL-treated soils did not adequately fit to the Langmuir isotherm. The constants of sorption isotherms were lowered by SL application. The mean sorption maxima, binding energy and maximum buffering capacity values decreased by 38.85, 21.34 and 38.90 % respectively. The mean distribution coefficient, Freundlich n and the mean buffering capacity (slope of linear model) values decreased by 21.7, 16.0 and 6.1 %, respectively. The results of this study showed that application of SL decreases standard phosphorus requirement. Moreover PSC results indicated that use of sewage sludge might increase the risk of P transfer to surface water.
L. Rahimi, N. Aliasgharzad, Sh. Oustan,
Volume 15, Issue 58 (winter 2012)
Abstract
Azotobacter chroococcum can improve mineral nutrition of plants through N2 fixation and plant growth promoting capabilities. Fourteen strains of A. chroococcum were isolated from rhizosphere of wheat plants grown in different field conditions around Tabriz, northwest of Iran. In a pot culture experiment with sterile soil, wheat plants (Triticum aestivum cv. Falat) were inoculated with 14 bacterial strains. Positive control received nitrogen fertilizer without bacterial inoculation and the negative control was left un-inoculated and without N- fertilizer. Totally, 16 trearments with four replications were arranged in a completely randomized design. The plant growth indices and N and P concentrations of shoot and root were determined at the harvest time. Results showed that the inoculation with Azotobacter strains caused a significant increase in shoot and root dry weights. Bacterial inoculation significantly enhanced the concentration and content of N in shoot and root. Phosphorus content was only enhanced (p<0.05) in the root. Translocations of N and P from root to shoot were markedly increased in bacterial treatments compared to the positive and negative controls. Moreover, strains 1 and 48 which showed relatively higher phosphate solubilizing capability and phosphatase activity in in-vitro assay also brought about higher P content and concentration in shoot and its translocation from root to shoot.
N. Najafi, S. Mardomi, Sh. Oustan,
Volume 15, Issue 58 (winter 2012)
Abstract
The effects of waterlogging, sewage sludge and manure on the Fe, Mn, Zn, Cu, Pb and Cd uptake and concentrations in roots and shoots of sunflower (Helianthus annuus L.) were investigated in greenhouse conditions. A factorial experiment based on a completely randomized design with three replications including duration of waterlogging at five levels (0, 2, 4, 8, 22 days) and source and amount of organic fertilizer at five levels (0, 15 and 30 grams of both manure and sewage sludge per kg of soil) was conducted. The results showed that by increasing the duration of waterlogging, the Mn uptake and concentration in shoots and Mn concentration in roots increased but Mn uptake in roots did not change significantly. The uptake and concentration of Fe in shoots and Cd concentration in shoots and roots initially increased and then decreased after soil waterlogging, while Zn and Cu concentration of roots increased after an initial decrease. The effect of soil waterlogging on the Pb, Cu and Zn concentrations in shoots was not significant. By application of sewage sludge and manure the uptake and concentration of Fe, Mn, and Zn in shoots and Cu uptake in shoots increased but the uptake and concentration of Pb in shoots increased only by application of sewage sludge. The effect of source and amount of organic fertilizer on the Cd uptake and concentration in shoots, Cd concentration in roots and Cu concentration in shoots was not significant. By application of sewage sludge the root concentration of Fe, Mn, Cu and Zn increased but root concentration of Cd and Pb did not change significantly. The maximum uptake of heavy metals in shoots was obtained by application of 30 g sewage sludge/kg of soil. The effect of soil waterlogging on the heavy metals uptake and concentrations in the roots and shoots was dependent on the source and amount of organic fertilizer. Sunflower plant accumulated Fe, Mn, Zn, Cu, and Pb in roots while the Cd concentration in roots did not differ with shoots significantly.
S. Heydari, S. Oustan, M.r. Neyshabouri, A. Reyhanitabar,
Volume 19, Issue 72 (summer 2015)
Abstract
Consequences of heavy metal accumulation in soils are of great concern. One way of decontaminating heavy metals from soils is using chelating agents, particularly EDTA. In this research, three contaminated soils (with total concentration of these metals of 10.5, 55.8 and 80.6 mmol kg-1) were collected from the surface layer of the lands surrounding a zinc-lead smelting plant in Zanjan province. The extent of Zn, Pb and Cd release by Na2H2EDTA (100 mmol kg-1 of dry soil) from these soils in column leaching experiments (both continuous and pulse addition methods) assembled into half of saturated hydraulic conductivity was assessed. In preliminary experiments, the leaching was stopped due to a drop in hydraulic conductivity. Therefore, the continuous addition method was performed with calcium nitrate as the background solution and the pulse addition method was conducted using this background solution coupled with pH adjustment to 8. Based on the results, the percentage removal of Cd as well as Pb was relatively the same for the two addition methods while the removal of Zn was 13% on average higher in the continuous addition method than in the pulse addition method. For both methods, the removal efficiencies followed the order of complex stability constants (as Pb>Zn>Cd) in a limited concentration range of EDTA to complex heavy metals. Furthermore, in contrast to Cd and Pb, a direct linear relationship was found between the percentage removal of Pb and its total amount in the soils. Surprisingly, the Pb concentration was on average only about one-twentieth of the Zn concentration. The breakthrough curves of both methods showed the mobility order of Cd>Zn>Pb. In general, it seems that the removal pattern of soil heavy metals is dependent not only on the soil type but also on the removal method.
J. Saleh, N. Najafi, S. Oustan,
Volume 19, Issue 72 (summer 2015)
Abstract
The present study was conducted in order to investigate the effects of silicon and salinity on growth, chemical composition and physiological properties of rice var. Hashemi, in the greenhouse of agricultural college of University of Tabriz during 2011. It was arranged as factorial based on a completely randomized design with three factors consisting of silicon at four levels (control, 100, 200 and 300 mg/kg soil), salinity at four levels (control, 2, 4 and 8 dS/m) and source of salinity at two levels (NaCl and combination of different salts) with three replications. The results showed that increasing soil salinity resulted in a decrease in shoot dry weight, catalase activity and concentrations of phosphorus, potassium and reducing sugars, and an increase in glycine betaine content in the plants. The comparison between two sources of salinity also revealed that plants treated with a combination of salts experienced less vigorous decrease in dry weight and potassium, and reducing sugars' concentrations. Meanwhile, the enhancement in glycine betaine content appeared to be less intense in these plants. Hence, it could be concluded that the salinity resulting from a combination of different salts caused less damage to plants than NaCl salinity. Silicon supplementation resulted in increasing of shoot dry weight, catalase activity and concentrations of reducing sugars, glycine betaine, phosphorus and potassium. Therefore, silicon nutrition alleviated suppression effects resulting from the presence of soil salts, which means, enhanced the salt tolerance of rice.
R. Darabi Kandlaji, Shahin Oustan, Nasser Aliasgharzad, N. Najafi,
Volume 22, Issue 3 (Fall 2018)
Abstract
Nitrification is one of the most active biological processes in the soils receiving ammonium nitrogen. The rate of this process is under the influence of several factors and their interactions. In this study, the effects of ammonium concentration and moisture content on the extent of nitrification in two soil samples named A (Loam) and B (Clay loam), which had been taken, respectively, from Marand and Ahar areas, were investigated. A two-week factorial incubation experiment (25±0.5°C) was conducted in a completely randomized design with three replications. Factors were urea nitrogen at five levels (0, 50, 100, 200 and 400 mg N kg-1), moisture content at three levels (0.55FC-0.60FC, 0.75FC-0.80FC and 0.95FC-FC) and two soil types (A and B). At the end of the experiment, concentrations of ammonium and nitrate as well as the values of pH and EC were determined. Based on the results, average nitrification at 0.55FC-0.60FC was 22 percent lower than that at 0.95FC-FC and no significant difference was observed between 0.75FC-0.80FC and 0.95FC-FC. Nitrification at the treatment of 400 mg N kg-1and 0.55FC-0.60FC was decreased considerably and 25 percent of the added ammonium was accumulated. The average ammonium concentrations did not significantly vary among the levels of 50, 100 and 200 mg N kg-1, but these concentrations were significantly lower than those of 400 mg N kg-1. Moreover, EC and pH values of the soils were significantly increased and decreased in response to the nitrification (0.54 dS m-1 and 0.59 at the application level of 200 mg N kg-1, respectively). On average, the results showed higher nitrification (40.3 mg N kg-1) in the soil A (Loam texture) than the soil B (Clay loam).
M. Boustani, F. Mousavi, H. Karami, S. Farzin,
Volume 23, Issue 4 (Special Issue of Flood and Soil Erosion, Winter 2019)
Abstract
River discharge is among the influential factors on the operation of water resources systems and the design of hydraulic structures, such as dams; so the study of it is of great importance. Several effective factors on this non-linear phenomenon have caused the discharge to be assumed as being accidental. According to the basics the chaos theory, the seemingly random and chaotic systems have regular patterns that are predictable. In this research, by using methods of phase space mapping, correlation dimension, largest Lyapunov exponent and Fourier spectrum power, a period covering 43 years of Zayandehrud River discharge (1971-2013) was evaluated and analyzed based on the chaos theory. According to the results, the non-integer value of the correlation dimension for Eskandari and Ghale Shahrokh stations (3.34 and 3.6) showed that there was a chaotic behavior in the upstream of Zayandehrud-Dam Reservoir. On the other hand, in the Tanzimi-Dam station, the correlation dimension curve was ascending with respect to the embedding dimension, showing that the studied time-series in the downstream of Zayandehrud-Dam Reservoir was random. The slope of the Lyapunov exponent curve for Eskandari, Ghale Shahrokh and Tanzimi-Dam stations was 0.0104, 0.017 and 0.0192, respectively, and the prediction horizon in the chaotic stations was 96 and 59 days. The non-periodical feature of time series was studied by using the Fourier spectrum power. The wide bandwidth, besides other indices, showed that river discharge in the upstream stations of Zayandehrud Reservoir was chaotic.
A. Malekian1, A.a. Jafarazdeh, Sh. Oustan, M. Servati,
Volume 26, Issue 2 (ُSummer 2022)
Abstract
To study the soil-landscape change in the Chaldoran region, 9 representative soil profiles were studied in 5 dominant geomorphic units of the study area including piedmont plain, mantled pediment, alluvial fan, plain, and flood plain. The results showed that the accumulation of pedogenic carbonate in some soils was concretion and light in color. In control soils in the piedmont plain (profile 5 and 7), mantled pediment (profile 6), and flood plain (profile 8) clay transferred from the surface horizons and accumulated in the lower horizon, due to relatively good rainfall in the region and distinct dry and wet seasons has led to the formation of argillic horizons along with the formation of crust on the surfaces of aggregates and building units and has formed the Alfisoils order. Mineralogical results showed the presence of chlorite, illite, kaolinite, and smectite minerals. According to the evidence, illite, chlorite, and kaolinite minerals were inherited and smectite minerals were formed due to weathering and evolution of illite, chlorite, or palygorskite minerals. Also, the results of the CIA index in the region indicated that the soils of the region are in the stage of weak to moderate weathering. In general, the results indicated the critical role of drainage, land use, and parent materials in the soils of the study area.
