Showing 33 results for کلسیم
Sh. Kiani, Gh. Zadeh Dabagh, M.j Malakouti, A. Alizadeh ,
Volume 14, Issue 51 (4-2010)
Abstract
Gray mold, caused by Botrytis cinerea, is a serious disease of cut rose flowers (Rosa hybrida L.) in Iran. In order to elucidate the effects of different potassium and calcium levels in nutrient solution on susceptibility of cut rose flowers to gray mold, this experiment was carried out as factorial design in a randomized complete block with four replications at Safi Abad Agricultural Research center in 2008 for one year. In this experiment, rose plants were grown and subjected to three levels of potassium (1.0, 5.0 and 10.0 mM) in combination with two levels of calcium (1.6 and 4.8 mM) under hydroponic condition. Rose flowers from two consecutive harvesting periods were sprayed with the conidial suspension (104 spore/ml) of B. cinerea isolate. At the end of experiment the disease severity was recorded and analyzed. The results indicated that application of 10.0 mM K in the nutrient solution led to increasing rose disease severity to gray mold (30.4 % day-1) compared to 1.0 mM (24.8 % day-1) and 5.0 mM (26.2 % day-1) of K levels (P< 0.01). The increased susceptibility was associated with a decreased concentration of Ca in the rose petals. Correlation analysis revealed that susceptibility of rose flowers to gray mold significantly increased with K to sum cations ratio in the nutrient solution (r = 0.94*). The increase of Ca supply from 1.6 to 4.8 mM resulted in decline of disease severity from 29.6 to 24.6 % day-1 (P< 0.01). Therefore, balanced application of potassium and calcium (5.0 and 4.8 mM, respectively) is recommendable for preventing antagonistic effects between them and reducing of rose gray mold intensity under hydroponic conditions.
M Gorgi, M Zahedi, A. H Khoshgoftarmanesh2,
Volume 14, Issue 53 (10-2010)
Abstract
An experiment was conducted in order to evaluate the effects of increased concentration of potassium and calcium in hydroponic nutrient solution on the response of safflower to salinity. The experiment was carried out in a glasshouse using a completely randomized design. Four saline treatments (Johnson solution containing 100 mM of NaCl, Johnson solution containing 100 mM of NaCl + 10 mM potassium, Johnson solution containing 100 mM of NaCl + 5 mM calcium, Johnson solution containing 100 mM of NaCl + 10 mM potassium + 5 mM calcium) and Johnson solution without any addition of salt as control. Leaf area per plant, shoot and root dry matter was decreased in saline treatments. The concentration of potassium and calcium in the plants were decreased but those of sodium were increased at salinity. The extent of shoot and root dry mater reduction with salinity was less in saline treatment with additional calcium alone. The addition of potassium into the nutrient solution could not mitigate the negative effects of salt stress on the plants. Increasing the concentration of both potassium and calcium in saline nutrient solution resulted in a greater reduction of shoot dry matter. The results showed that the negative effects of salinity may be alleviated by increasing the concentration of calcium in nutrient solution.
M. Bahreini Touhan, E. Dordipour, S. A. Movahedi Naeini,
Volume 14, Issue 53 (10-2010)
Abstract
Kinetical study on non-exchangeable potassium (NEK) release is necessary for management, optimum use of soil resources, availability and supplying power of potassium. Information about NEK release rate in Golestan soils is limited. The aim of this study was to investigate the NEK release of saturated soil sample by calcium using acid citric and CaCl2 extractants from 2 to 1844 h duration in 12 dominant soil series in Golestan province. Different soils indicated various responses to continuous extraction. The rate of K released in different soils was lower in CaCl2 than that of Citric acid. Potassium release was faster in earlier periods of the extraction in all soils followed by a lower release rate. Due to high coefficient of determination and low value of the standard error of the estimate, the NEK release kinetic by citric acid and CaCl2 were well described by Elovich and Parabolic diffusion equations and Power, First order and Elovich equations, respectively. Therefore, NEK release rate was controlled by K diffusion from weathered surface of soil minerals.
M. Ansari Azabadi , H.shirani, H. Dashti, A. Tajabadipur ,
Volume 15, Issue 57 (10-2011)
Abstract
Calcareous and gypsiferous soils are restricting factors for uptake of some plant nutrient elements and plant production. Most soils in Iran are calcareous and gypsiferous. Therefore, the aim of this study was the evaluation of calcium carbonate (Caco3) and gypsum effect on availability of some nutrients and corn growth. This study was conducted in a greenhouse at Vli-e-Asr University of Rafsanjan. Treatments were arranged in a factorial manner as a completely randomized design with three replications. Treatments were three levels of Caco3 (0, 20 and 40 g/100g soil), gypsum at three levels (0, 15 and 30 g/100g soil) and two soil textures (Sand and Silt clay loam). Results indicate that irrespective of soil texture, Caco3 application significantly decreased leaf area (by 80% and 15% for sand and silty clay loam texture, respectively), dry weight (by 80% and 15% respectively), plant height (regressed on Caco3 percentage by slopes -0.7 and -0.15 for sand and silty clay loam respectively), and shoot Fe (-9.67 and -11.3) and Zn (-0.24 and -1) uptake, but had no significant effect on shoot Cu uptake. In sandy soil, application of gypsum, significantly decreased leaf area (80%), dry weight (62%), and shoot Cu uptake (slope= -1.93), but had no significant effect on plant height and shoot Zn uptake. Gypsum application significantly reduced shoot Fe uptake (slope= -24.86) in fine textured soil, but it had no significant effect in coarse textured soil.
H. Kheirabad, A. H. Khoshgoftarmanesh, Z. Khanmohamadi,
Volume 16, Issue 62 (3-2013)
Abstract
Due to soil and plant zinc (Zn) deficiency and its effect on reducing yield and quality of agricultural products, application of Zn fertilizers has been intensified in recent years. To achieve optimum fertilizer management, knowledge of factors affecting Zn availability in soil and its uptake by plant is required. Therefore, this study was carried out to investigate the effect of certain soil physiochemical properties on Zn availability in soil and its uptake by corn. The experiment was laid out in a completely randomized design with factorial combination and three replicates in the research greenhouse of Isfahan University of Technology, in winter 2009. In this greenhouse experiment, 11 soil series were exposed to two Zn levels (0 and 15 mg Zn kg−1 in the form of zinc sulfate). The results indicated that Zn application significantly increased the dry matter weight and shoot and root Zn concentration of corn, although the magnitude of this increase varied depending on the soil type. There was no significant correlation between the DTPA-extractable Zn and the uptake of this nutrient element by corn. There was a negative significant correlation (P < 0.05) between the equivalent calcium carbonate content and available P with the DTPA-extractable Zn. A significant linear relationship (R2 = 0.31) was found between the buffer capacity of soil for Zn and clay content. According to the results obtained from the stepwise regression analysis, the DTPA-extractable Zn and buffer capacity of soil for Zn were not correlated with other measured soil properties.
Alireza Hosseinpur, Hamidreza Motaghian, Tahereh Raeisi Gahrooee1,
Volume 17, Issue 64 (9-2013)
Abstract
Information about potassium (K) release characteristics in the Chaharmahal-va-bakhtiari soils is limited. In this study, K release kinetics of fifteen calcareous soils was investigated. Soil samples were extracted using successive extractions with 0.01 M CaCl2 and citric acid solutions for 2-2017 h at 25±1 0C. Moreover, soil K was determined using 6 chemical extraction methods. The results showed that released K ranged from 111 to 411 mg kg-1in calcium chloride solution and from 177 to 1199 mg kg-1 in citric acid solution for 2017 h. Amounts of extracted K using any extraction methods were different. Result of kinetics study and chemical methods indicates that K supplying power of the soils is different. A plot of cumulative amounts of released K shows a discontinuity in slope at 168 h. Thus, two equations were applied to the total reaction time (2 to 168 and 168 to 2017 h). Moreover, results showed that release kinetics of K conformed fairly well to parabolic diffusion, simplified Elovich and power function models in two segments in 0.01 M CaCl2 and citric acid. In addition, results showed that correlation between released K by using 0.01 M calcium chloride and citric acid and extracted K using chemical methods was significant. The results of this research showed that kinetic studies and soil testing could be used for evaluating K fertility status of studied soils.
H. R. Owliaie, S. Heydarmah, E. Adhami, M. Najafi Ghiri,
Volume 18, Issue 68 (9-2014)
Abstract
Rate of nonexchangeable K release can significantly influence K availability. Kinetics of K+ release was studied by extraction using 0.01 M CaCl2 in 12 surface calcareous soils of Kohgilouye Province. Results showed that cumulative K release ranged from 89.9 to 460.9 mg kg-1(Average 195.4 mg kg-1). Calcium carbonate, nonexchangeable K, cation exchange capacity and mica showed a significant correlation with K release. Maximum of potassium release was observed in Alfisols, probably because of high amount of clay content and the clay mineral of mica. The amount of K release was in the following order: Alfisols> Entisols> Inceptisols. Elovich, parabulic diffusion and power function equations could reasonably describe the K release kinetics. Fitting the data to these equations indicated that release of K is controlled by diffusion process.
S. Shakeri, S. A. Abtahi, N. A. Karimian, M. Baghernejad, H. Owliaie,
Volume 19, Issue 73 (11-2015)
Abstract
The aim of this study was to assess the kinetics of nonexcheangable potassium release in surface and subsurface soil horizons, using organic and inorganic extractions, in Kohgilouye-va-Boyerahmad Province. Kinetics of K+ release was studied by successive extractions of K from 64 selective surface and subsurface soil samples, using 0.01 M CaCl2 and 0.01 M oxalic acid, for 1948 h, with two replicates. Nonexchangeable K+ release was fitted by Elovich, Pseudo-first order, Power function and Parabolic equations. Result showed that the average nonexchangeable K+ released (extracted by 1M HNO3) was 356 mg/kg, while those extracted by CaCl2 and oxalic acid after 1948 h were only 58% and 52% of the total amount of nonexchangeable K+ of the soils, respectively. In all soil samples, nonexchangeable K+ released by oxalic acid was less than that released by CaCl2, due to the high buffering capacity resulting from high carbonates in the soils. Potassium release rate in Elovich and Parabolic equations were significantly correlated with non-exchangeable potassium and some physical and chemical characteristics. Based on high Coefficients of determination (r2) and low Standard errors (SE), Elovich, Power function, First order and Parabolic equations were selected as the best equations for prediction of K+ release from the soils.
M. Mir Mohammad Sadeghi, A. R. Sotoudehfar, E. Mokhtari,
Volume 20, Issue 77 (11-2016)
Abstract
Improvement of soils is among the major concerns in civil engineering, therefore a variety of approaches have been employed for different soil types. The annual budget of implementing the projects of this kind in countries clearly implies the importance of the subject. The loose granular soils and sediments have always imposed challenges due to their low strength and bearing capacity. Bio-mediated soil improvement has recently been introduced as a novel link of biotechnology (biotech) and civil engineering for improving the problematic soils, i.e. utilizing some bacteria to precipitate calcite on the soil particles. Bio-grouting is a branch of Bio-mediated soil improvement which is a method based on microbial calcium carbonate precipitation. In this regard, the soil samples were stabilized by injecting the bacterium Sporosarcina pasteurii in the first phase of the process and Urea and Calcium Chloride in the second phase of the process (two-phase injection) as the nutrients into the sandy soil columns and subjected to unconfined compressive strength test. In this research, Taguchi method was utilized for design of experience (DOE). Based on results obtained, the activity of the bacteria caused the precipitation of calcium carbonate in soil samples so that after 21 days, the unconfined compressive strength of the soil increased from 85 kPa in the control sample to 930 kPa at optimum condition.
S. Z. Atar Shahraki, A. R. Hosseinpur, H. R. Motaghian, Sh. Ghorbani,
Volume 22, Issue 1 (6-2018)
Abstract
The study of the kinetics of non-exchangeable potassium (NEK) release is very important for a better understanding of K availability for plants in different soils. Moreover, aggregates with different sizes have different effects on the release of nutrients. Therefore, the aim of this study was to examine the release of NEK in 5 calcareous soils of chaharmahal-va- bakhtiari province, and small and large aggregates (<250 μm and >250 μm) using CaCl2 0.01 M at 25±1ºc for 2-2017 h. The results showed that cumulative released NEK in soils, and small and large aggregates was 173.5-372.7, 215.1-426.1 and 178.9-381.5 mg kg-1, respectively. The results revealed that coefficients of the cumulative released NEK in small aggregates was lower than those of the soils and large aggregates. Based on the coefficient of determination (R2) and standard error (SE), the released NEK was well described by the first order, the power function, parabolic diffusion, and simplified Elovich equations. The rate coefficients of the release of K were different in different soils. The cumulative released amount of K and its rate of release in a solution of calcium chloride in small aggregates was more than those of large aggregates.
S. Shakeri, S. A. Abtahi,
Volume 22, Issue 4 (12-2018)
Abstract
This research was carried out to assess the origin and clay minerals characteristics and their relationship with potassium forms in the calcareous soil of this region, with the humid climate conditions. Based on aerial photos and topographic maps, physiographic units were separated and soil sampling was done in each diagnostic horizon. The results showed that smectite was the main and dominant clay mineral in the study area. In well-drained pedons, the convincing process for smectite abundance seemed to be mainly the transformation of palygorskite and mica. According to the results, the exchangeable potassium in the surface horizon was higher than that of the subsurface horizons. The main reason for the higher level of exchangeable K in the soil surface, was more smectite and organic carbon. The results revealed that unlike exchangeable and non-exchangeable K, because of the suitable conditions like temperature and humidity in surface horizons, the relative mean of structural K in the surface soils was less than that in the subsurface. Also, since an increase in calcium carbonate resulted in a decrease in amount of clay and the amount of relative clay minerals (dilution effect), the amounts of exchangeable, non- exchangeable and structural K were decreased.
A.r Modares Nia, M. Mirmohamad Sadeghi, A. Jalalian,
Volume 25, Issue 4 (12-2021)
Abstract
Desertification has become one of the main problems of human societies living in the vicinity of desert areas in recent years. One of the methods that have been considered in recent years and are rapidly expanding in the field of soil mechanics is the Microbial Induced Carbonate Precipitation (MICP). In this method, urea-positive organisms that are naturally present in the soil can stabilize the soil and improve its engineering parameters by using urea and calcium chloride. Recently, attempts have been made to use this method to create a crustal layer on the soil to prevent wind erosion. In the present study, the effect of environmental conditions in deserts such as temperature and sand bombardment on microbial soil treatment has been investigated using this new method. The soil of the Segzi region as one of the main centers of dust in the Isfahan region was studied in this research. Therefore, the improved samples are subjected to regional temperatures which increased the surface layer resistance with increasing temperature. Also, the sandstorm conditions of the region were simulated using three different grain sizes of sand inside the wind tunnel. The results of these experiments showed that stabilized soil could withstand the conditions at wind speeds of 7 and 11 m/s. However, by increasing the wind speed to 14 m/s and the grain size, the crustal layer destroys and increases the wind erosion of the soil. Also, the resistance of the surface layer increased by increasing temperature in the tested samples. This increase in resistance continued up to 24 degrees with a high slope, but from 24 degrees onwards, this slope decreases. Based on the results of this research, it can be said that the microbial improvement method can be used as an alternative method in the future to stabilize desert soils.
A.r. Hossienpur, M. Barati, M.h. Salehi,
Volume 27, Issue 4 (12-2023)
Abstract
The kinetics of potassium release may be affected by P When phosphorus (P) fertilizer is applied to soils. The objective of this study was to the effect of Ca(H2Po4)2 fertilizer on the kinetics of non-exchangeable potassium (NEK) release in 10 calcareous soils. The amount of 100 mg kg-1 of P as Ca(H2Po4)2 was added to the soils. Treated and untreated soils were incubated at 70% of field capacity and 25±1°C for 90 days. After that, the NEK release was studied by 0.01 M CaCl2 extractant in 2017 hours by successive extraction methods in the treated and untreated soils. The results showed the NEK released in treated soils less than in untreated soils. The mean cumulative NEK released after 2017 h in the treated and untreated soils was 260.6 and 303.3 mg kg-1, respectively. The release of NEK in all soils was fast in the initial stages and continued at a lower speed in the later stages until the end of the experiment. The kinetics of NEK release was evaluated using kinetic equations. Based on the highest coefficients of determination (R2) and the lowest standard error (SE), the kinetics of NEK release in treated and untreated soils were described by the power function equation. The results of this research could be helpful for the precise fertilizer recommendation for the study in calcareous soils.
