Showing 22 results for Calcium
M. Afsharmanesh, J. Pourreza,
Volume 3, Issue 3 (10-1999)
Abstract
An experiment was carried out to study the effect of different levels (3.06, 3.23, 3.4, 3.57 and 3.74%) of calcium and vitamin D3 supplementation (2000, 2200 and 2400 IU/kg diet) on the performance of laying hens. In a completely randomized design and in a 5 × 3 (15 treatments) factorial arrangement, two hundred and forty (240) white leghorn laying hens strain Hy-Line W 36, 26 weeks old, were divided into 60 replicates, four hens per replicate. The experimental period lasted 90 days, until the hens reached 38 weeks of age. The results indicated that calcium levels did not have any significant effects on the percentage of egg production, feed consumption, feed conversion ratio and egg mass. Egg weight significantly (P < 0.05) increased at 3.4% Ca level. Vitamin D3 had no significant (P < 0.05) effects on egg weight, feed consumption and egg mass, but feed conversion ratio significantly (P < 0.05) decreased and percentage of egg production raised significantly (P < 0.05) due to added vitamin D3. Interaction between vitamin D3and calcium on egg weight and egg production was significant (P < 0.05). The regression equations indicated that performance traits can be estimated from calcium and vitamin D3levels in diet.
M. Maftoun, H. Haghighat Nia, N. Karimian,
Volume 4, Issue 2 (7-2000)
Abstract
As apparent Zn recovery in mineral soils (saturated and unsaturated) is nill, the precise assessment of processes responsible for Zn retention in these soils is of great importance. A laboratory study was conducted to characterize Zn adsorption in eight lowland calcareous soils. The fit of sorption data was evaluated by Freundlich and Langmuir isotherms. In this study, 2-g soil samples were equilibrated for 24 hours with 40 mL 0.0lM CaCl
2 solution containing 5 to 500 mg Zn L
-1. The amount of Zn adsorbed was calculated based on the difference between the initial and equilibrium Zn concentrations.
Zinc adsorption data were fitted to a linear form of Freundlich equation. However the Langmuir isotherm was divided into two distinct linear portions, representing two different types of adsorption sites. The Langmuir K1 was higher and adsorption maxima (b1) was lower in part I (corresponding to lower Zn concentration) than in part II (corresponding to higher Zn concentration). Thus, it seems that in parts I and II, sites are more important for their high adsorption energy and adsorption capacity, respectively. Langmuir adsorption maxima (b2) was positively correlated with clay content, CCE and P concentration and negatively correlated with CEC.
M. Azad, E. Izadi-Darbandi, M. H. Rashed Mohassel,
Volume 4, Issue 11 (4-2014)
Abstract
In order to study the effect of soil nitrogen content and water hardness on glyphosate efficacy on common lambsquart control, an experiment was carried out as a completely randomized design in a factorial arrangement with three replications in 2011 at the College of Agriculture, Ferdowsi University of Mashhad. Experimental treatments were included soil nitrogen content at 5 levels (0, 50, 90, 200 and 300 mg/kg soil), glyphosate doses at 7 levels (0, 75, 100, 125, 150, 175 and 200 % dose guideline glyphosate for common lambsquart), calcium carbonate concentration in water as index of water hardness at 5 levels ( 0, 100, 300, 600 and 1200 ppm). Spray was done at 8-10 common lambsquart leaf stage. 30 days after glyphosate spray, plants survival and shoot dry matter was measured. Results showed, herbicide rate, soil nitrogen content and water hardness had significantly affect (P<0.01) on growth and survival of common lambsquart. Increasing herbicide doses decreased common lambsquart survival and growth in pure water spraying. Increasing water hardness decreased glyphosate efficacy in control common lambsquart and increased glyphosate ED50 parameter. The lowest (1453.17 gr. a.i ha-1) and the highest (3424.45 gr. a.i ha-1) glyphosate ED50 for common lambsquart was observed in 0 and 1200 ppm of water hardness. Increasing soil nitrogen content from 18 to 300 (mg/kg soil) increased glyphosate efficacy in common lambsquart and glyphosate ED50 decreased from 3217.03 to 1612.58 (gr. a.i ha-1).
M. Ashouri Vajari, M. Ghasemnezhad, A. Sabouri, R. Ebrahimi,
Volume 4, Issue 13 (1-2015)
Abstract
The main factor affecting fruit quality and post-harvest loss in kiwifruits is improper tree nutrition. In this study, fruits were harvested from 24 different orchards in the east of Guilan province when the total soluble solid content of the fruit was 6.2°. percent the fruts was. Fruits’ mineral content such as nitrogen, phosphorus, potassium, calcium and magnesium, the mineral elements ratios and also fruits firmness were measured after harvest. Thereafter, fruits were transferred to cold storage at 0 ºC temperature and 90% relative humidity and after 15 weeks, fruit tissue firmness, water loss, ethylene content and respiration severity were measured. There was a significant positive correlation between fruits tissue firmness with fruit calcium content, but a significant negative correlation with potassium and nitrogen content, N:Ca, N+K:Ca. K:Ca and K+Mg:Ca ratios. At the end of storage, there was a significant positive correlation between fruit tissue firmness with calcium content at harvest time and a significant negative correlation with nitrogen, phosphor us and potassium content and N:Ca, N+K:Ca, K:Ca and K+Mg:Ca ratios. Furthermore, fruits’ weight loss showed a significant positive correlation with potassium content. There was a significant negative correlation between ethylene level and fruit tissue firmness at the end of storage and a positive correlation with N:Ca and N+K:Ca ratios. Cluster analysis divided kiwifruit orchards into two main groups. In conclusion, the results showed that the kiwifruit mineral elements’ content and ratio at harvest time can be used as an effective factor for evaluating post-harvest life of kiwifruits.
M. Afsharmanesh, J. Pourreza, A. Samie,
Volume 5, Issue 2 (7-2001)
Abstract
This experiment was carried out to study the effect of different levels (3.06, 3.23, 3.4, 3.57 and 3.74%) of calcium and vitamin D3 (2000, 2200 and 2400 IU/kg diet) on eggshell quality of laying hens. In a completely randomized design and in a 5×3 (15 treatments) factorial arrangement, two hundred and forty (240) white leghorn laying hens, strain Hy-Line W36 and 26 weeks old, were divided into 60 replicates, four hens per replicate. The experimental period lasted 90 days until the hens were 38 weeks of age.
The results indicated that shell strength, shell thickness and shell percentage increased significantly (P<0.05) at 3.06% Ca level. Calcium levels had no effect on ash shell percentage. Vitamin D3 did not have a significant (P<0.05) effect on ash shell percentage and calcium shell, but shell strength, shell thickness and shell percentage significantly (P<0.05) increased at 2400 IU/kg diet vitamin D3. Only plasma calcium raised significantly (P<0.05) due to the added vitamin D3. Interaction between vitamin D3 and calcium on shell strength, shell thickness, shell percentage and plasma calcium were significant (P<0.05). Correlation between egg shell quality parameters and blood parameters with calcium and vitamin D3 was significant (P<0.05).
M. Zohravi, H. Nassiri Moghadam, F. Eftekhari Shahroodi, M. Danesh Mesgaran,
Volume 5, Issue 3 (10-2001)
Abstract
An experiment was carried out on 384 7d old commercial broiler chicks (Lohman) to study the effect of changes in source and level of dietary calcium and limestone particle size on the performance and tibial growth and calcification of broiler chicks. From day 1 to day 7, the chicks were fed with the commercial basal diet. On day 7, the chicks were weighted and randomly assigned to 64 groups, six chicks of similar body weight (82.2±5.4) per group. Each of the eight experimental diets was fed to eight groups of chicks for an experimental period of 49 days. Two calcium sources (oyster shell and limestone), two calcium levels (100% NRC and 85% NRC) and three particle sizes of limestone [ground (less than 0.15 mm), medium (0.6 to 1.18 mm) and coarse (1.18 to 4.75 mm)] were added to diets with the same energy based on a Randomized Complete Design, in which levels of calcium were nested into calcium sources. Particle sizes were nested into calcium sources and levels.
Limestone significantly increased phosphorus retention (in percentage of phosphorus ingestion) at the age of 21 and 56 days and increased tibial length, dry weight and ash weight at 56 days. Calcium level of 85% NRC significantly decreased feed intake and feed conversion, especially during the starter, and increased calcium retention (in percentage of calcium ingestion) at 21 and 42 days. Phosphorus retention and cortical thickness of tibia at 21 and 42 days, tibial dry weight, ash weight and ash percentage at 42 day, were significantly increased with calcium level of 100% NRC. Coarse and medium particle sizes of limestone as compared to ground particle size, significantly improved feed intake and feed conversion, especially during the starter. Medium particle size of limestone with calcium level of 85% NRC and coarse particle size of limestone with calcium level of 100% NRC, significantly improved tibia ossification characteristics and increased calcium and phosphorus retention. By using calcium level of 85% NRC, coarse and medium particle sizes of limestone compared to ground particle size, significantly diminished percentage of leg abnormalities.
M. K. Souri, M. Mahdavi,
Volume 5, Issue 16 (9-2015)
Abstract
Calcium is one the most important essential elements in plant growth and development. This element influences many physiological aspects of plant tissues even after harvesting. Calcium has also an important role in integrity and hardness of plant cells. In addition, calcium content of many horticultural crops is seen as a quality factor. Therefore, in this research effect of different calcium concentrations of nutrient solution on growth and development of two cut rose cultivars (Utopia and Dolce Vita) were investigated. This experiment was conducted as factorial based on completely randomized design during 2011. The factors were cultivar with two levels and calcium in four concentrations of 150, 220, 300 and 400 mg/l. The total number of treatments was 8 with 5 replications. The results showed that the effects of cultivar and calcium levels were significant on measured parameters. The analysis of variance of data showed that there were significant differences (p < 0.05) for some parameters including: length and diameter of flower stem and vase life of cut flower between two cultivars. Results also showed that with increasing calcium concentrations in nutrient solution the overall trend was to increase flowering parameters (p < 0.05). Therefore, increasing calcium levels up to 400 mg/l resulted in improvement of flowering parameters in both cultivars.
A. Ronaghi, M. R. Chakerolhosseini, N. Karimian,
Volume 6, Issue 2 (7-2002)
Abstract
Phosphorus (P) and iron (Fe) are essential nutrients for plants. Iron availability is low in calcareous soils of Iran due to the excessive amounts of CaCO3 and high pH. Overfertilization of P fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effect of P and Fe on the growth and chemical composition of corn (Zea mays L.) under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH2PO4) and Fe rates (0, 2.5, 5 and 10 mg kg-1 as Fe EDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, calssified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showd that P application up to 80 mg kg-1 increased corn top dry matter. Corn P concentration and total uptake increased by P application but decreased by Fe application. Application of Fe up to 5 mg kg-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Zinc and copper concentrations decresed significantly when P was added. Manganese concentration increased at 40 mg P kg-1 but decreased at higher rates. Iron application decreased zinc and manganese concentrations but had no effect on copper.
M. Sayyari, M. Rahemi,
Volume 6, Issue 4 (1-2003)
Abstract
‘Golden Delicious’ apples were vacuum infiltrated (250 mm Hg) with 0, 4, and 6% solutions of CaCl2 followed by heat treatment for 0, 48 and 72 hours at 38oC. Treated fruits were stored at 0oC with RH of 85-90% for 2.5 and 5 months, followed by one week of storage at 20C. The results showed that fruits treated with 4 and 6% of CaCl2 significantly increased calcium content of fruits after 2.5 and 5 months of storage at 0oC. With increasing calcium content, fruit firmness also increased. There was a positive relationship between fruit firmness and calcium content and regression coefficients after 2.5 and 5 months of storage at 0oC were 0.77 and 0.83, respectively. Heat treatment for 48 and 72 hours at 38oC significantly increased fruit firmness. Calcium chloride at 4 and 6%, plus heat treatment, significantly increased fruit firmness of those fruits held for one week at 20oC after removal from cold storage. In the second experiment, vacuum infiltrated fruits with 4 and 6% solutions of CaCl2 plus potassium permanganate (0, 10, and 20 g/bag) had no significant effect on fruit firmness, but potassium permanganate alone significantly increased fruit firmness.
M. R. Chakerolhosseini, A. Ronaghi, M. Maftoun, N. Karimian,
Volume 6, Issue 4 (1-2003)
Abstract
Iron (Fe) availability is low in calcareous soils of Iran due to high pH levels and presence of excessive amounts of CaCO3. Overfertilization by phosphorus (P) fertilizers may also decrease Fe availability. The objective of this study was to evaluate the effects of P, Fe and their interactions on the growth and chemical composition of soybean [Glycine max (L.) Merrill] under greenhouse conditions. Treatments consisted of a factorial arrangement of P rates (0, 40, 80, 120 and 160 mg kg-1 as KH2PO4) and Fe rates (0, 2.5, 5 and 10 mg kg-1 as FeEDDHA) in a completely randomized design with four replications. Plants were grown for 8 weeks in a loamy soil, classified as Chitgar series (fine-loamy, carbonatic, thermic, Typic Calcixerepts). Results showed that P application up to 80 and Fe at 2.5 mg kg-1 increased shoot dry matter. Phosphorus concentration, total uptake and P:Fe ratio in soybean increased by P application but decreased by Fe application. Application of Fe up to 2.5 mg kg-1 increased dry matter but decreased it at higher rates. Concentration and total uptake of Fe increased by Fe application but decreased by P application. Interaction of P and Fe had no effect on shoot dry matter. Zinc (Zn) and copper (Cu) concentrations decreased significantly when P was added and manganese (Mn) concentration increased up to 40 mg P kg-1 but decreased at higher rates. Iron application had no effect on soybean Zn and Cu concentrations but decreased Mn concentration at all rates. Prior to any fertilizer recommendations, it is necessary to study the effects of P, Fe and their interactions on soybean under field conditions.
Dr. Mirhassan Rasouli-Sadaghiani, Mr Mohammad Moghaddas Gerani, Miss Sanaz Ashrafi Saeidlou, Dr Ebrahim Sepehr,
Volume 7, Issue 2 (8-2017)
Abstract
In order to determine the effect of different Ca sources, in improving enzymatic activity and some qualitative properties of red apple (Malusdomestica) an experiment was carried out in a completely randomized design. Apple trees were sprayed 5 times with CaCl2, CaO, Ca-EDTA and Ca(NO3)2 salts with an interval of 20 days from late June until early October. After harvesting fruits were kept in cold storage at standard condition for 150 days. Nitrogen, phosphorus, potassium, calcium, magnesium, ascorbic acid, total soluble solids, firmness, total acidity, catalase enzyme activity and total antioxidant activity at harvest time, 50, 100 and 150 days after cold storage were measured. The results showed that the effect of foliar application on catalase enzyme activity, total antioxidant, pH, soluble solids, total acidity, calcium, firmness and ascorbic acid was significant. At the end of storage period, calcium amount of fruits at the presence of Ca-EDTA, CaCl2, Ca(NO3)2 and CaO treatments increased by 77.5, 27.5, 22.3 and 10.1 percent, respectively. Catalase enzyme activity in Ca-EDTA treatment increased 91.8 percent after 150 days of storage compared to control. At the end of the storage period, the highest content of ascorbic acid was found in Ca-EDTA treatment (6.04 mg per 100 g FW). It is concluded that spraying of apple fruit with Ca-EDTA can improve and maintain most fruit qualitative properties and increase enzymatic and antioxidant activity during storage time.
M. Pakdel, J. Pourreza, S. Ansari,
Volume 7, Issue 3 (10-2003)
Abstract
In a 3×3 factorial experiment, 90 72-week-old native breeder hens of Isfahan were kept in cages (one bird/cage). The effect of three levels of dietary calcium (3.27, 2.62, and 1.96%) and three levels of dietary available phosphorus (0.25, 0.20, and 0.15%) on egg production and egg shell traits were investigated. Each treatment contained five replicates of two birds (10 birds per treatment). The experimental diets were fed 8 weeks (from 72 to 80 weeks of age).
Dietary calcium and available phosphorus levels had no significant effects on feed consumption, shell thickness and shell breaking strength. Decreasing dietary calcium or available phosphorus levels (1.96% calcium and 0.15% available phosphorus) caused a significant (P<0.05) linear increase in egg production, egg weight and improvement in feed conversion. The results from this study showed that high egg production, maximum calcium retention in the shell and optimum feed conversion were observed in native breeder hens during late growing period with 1.96% calcium and 0.15% available phosphorus.
A. Kashi, S. Hosseinzadeh, M. Babalar, H. Lessani,
Volume 7, Issue 4 (1-2004)
Abstract
Watermelon (Citrullus Lanatus) cv. Charleston Gray is one of the most important cultivars grown in Iran. It has some good quantitative and qualitative characteristics but unfortunately is sensitive to Blossom End rot. To solve this problem, this experiment was conducted in a factorial manner in randomized complete block design with four replications in Research Station and Laboratories of Department of Horticulture, College of Agriculture, the University of Tehran, during 1997 & 1998. In this experiment, black polyethylene mulch was used and calcium nitrate was foliar sprayed at concentrations of 0, 4, and 6 g/L. Results indicated that mulch could increase yield by 85% over two years due to weed growth suppression and conserving soil moisture for a longer time. Foliage fresh weight, number and average weight of fruits per plant and precocity were also significantly affected by black polyethylene mulch. Furthermore, mulch reduced the number and weight of fruits affected by Blossom End rot by about 13% and 12.5% (average of two years), respectively. Calcium nitrate addition during both years had no significant effect on the measured fruit characteristics nor on Blossom End rot.
Z. Gheshlaghi, R. Khorassani, M. Kafi, A. Fotovat,
Volume 9, Issue 4 (1-2020)
Abstract
Reducing iron solubility in calcareous soils causes iron chlorosis symptoms in the plant. In order to investigate the response of M. scutellata to direct and indirect iron deficiency, a factorial experiment was conducted in a completely randomized design with three replications. The experimental factors included three levels of lime (0, 4 and 8%) and five levels of Fe (0, 5 and 10 mg Fe Kg soil-1 as soil application and 0 and 2.1 µM Fe as foliar spray). Zero Fe concentrations in soil and foliar Fe fertilization was considered as control-S and control-F treatment, respectively. The results showed that the amendment of 8% CaCO3 in control treatments caused typical Fe deficiency symptoms, including decreases in chlorophyll, total and extractable leaf Fe concentration, protein, leaf relative water content, membrane stability index and increases in leaf total phenolic and flavonoid concentration when compared to 0% lime. The soil and foliar Fe fertilisation led to the improvement of Fe chlorosis, increases in chlorophyll, Fe, protein, and decreases in concentration of phenolic compounds in three levels of lime. The foliar Fe fertilization in three levels of lime increased total and extractable leaf Fe content, compared to two soil Fe treatments, but foliar Fe fertilization (in 4 and 8% of lime) yielded progressively lower leaf phenolic compounds. The highest leaf chl concentration in 8% lime was observed in 10 mg Fe Kg soil-1 and foliar Fe fertilization. The presented data indicate that the use of foliar application of Fe (Fe- EDDHA) is potent to reduce the effects of lime induced chlorosis in plants in calcareous soils.
S. Sharifi, H. Sarikhani,
Volume 10, Issue 3 (10-2020)
Abstract
The role of calcium in the growth, fruiting and preservation of the quality of strawberries, has been well known. In this research, effect of calcium chloride along with naphthalene acetic acid (NAA) under shade conditions on growth, yield and quality of Paros strawberry was investigated. The experiment was a factorial with two factors of light intensity (normal light and shade condition) and calcium chloride and NAA treatment (control, 0.75% calcium chloride, 25 mg/L NAA, and 0.75% calcium chloride + 25 mg/L NAA). The results showed that spraying NAA and calcium chloride under shade conditions increased plant growth when compared with light conditions. Under normal light conditions, calcium chloride treatment increased the fruit diameter and yield in comparison with control treatment under light and shade conditions. The highest fruit firmness (342.0 N/cm2) was observed in the treatment of calcium chloride under light and shade conditions. NAA treatment under shade conditions resulted in higher anthocyanin. The treatment of calcium chloride + NAA in normal light condition showed higher total phenol (1.12 mg/g FW) and antioxidant activity (72.12%). Calcium chloride treatment increased the amount of calcium in the fruits by nearly 50%. Moreover, calcium chloride treatment in shade condition led to a 12% increase in calcium content of petiole, in comparison to those of control in shade condition. Calcium chloride along with NAA treatment increased leaf calcium compared to control treatment in light conditions. From the present results, it can be concluded that treatment of plant by calcium chloride alone in both light and shade conditions can increase the qualitative and quantitative characteristics of fruits of Paros cultivar of strawberry. Similarly, in some conditions, the use of NAA can, increase the absorption of calcium by the leaves.
F. Sharifi Kalyani, A. Siosemardeh, F. Hosseinpanahi, S. Jalali-Honarmand4,
Volume 11, Issue 4 (1-2022)
Abstract
In order to investigate the effect of seed priming on yield, yield components and some quality characteristics of rainfed wheat Azar2 cultivar, an experiment was conducted as a randomized complete blocks design with three replications in the Research Field of Kurdistan University, Sannandaj, Iran during two seasons (2018-2020). Priming treatments included control (nonprime), potassium chloride (1%), urea (2%), zinc sulfate (0.6%), calcium chloride (1.4%), vitasprin (1 g. l-1), cytokinin (50 ppm) and water (hydroprime). The results showed that in both years, priming of seeds with calcium chloride and water had positive effects on grain yield. In 2018-2019, calcium chloride priming increased the grain yield by 41% due mainly to increasing the number of spikes, biological yield and thousand kernel weight. In 2019-2020 grain yield increased by 10% due mainly to increasing thousand kernel weight. Also, in 2018-2019, seed priming with water increased grain yield by 27% due mainly to increasing the number of spikes and biological yield, and in 2019-2020 the 21% increase in grain yield was achieved by increasing biological yield and thousand kernel weight. Given the positive effects of hydropriming in both years and the high cost of using chemical compounds and nutrients for seed priming, hydropriming is proposed as a cost-effective method to increase grain yield of wheat in rainfed conditions.
M. Soltani Huwyzeh, S.a.m. Mirmohammady Maibody , A. Arzani,
Volume 11, Issue 42 (1-2008)
Abstract
Sugarcane is one of the most important sugar crops in the world. Because of semi-arid climate and salinity of its cultivation area in our country, increasing salt tolerance of sugarcane is signifying. To achieve this goal determining salt tolerant cultivars and understanding salinity mechanisms in sugarcane are very important. This study was conducted to evaluate 8 commercial and promising sugarcane cultivars at early stage of growth. A complete randomized design with three replicates and four salinity treatments (0, 0.25, 0.5, 0.75 % NaCl) was used in a hydroponics system. The effect of salinity on absorption, transport and accumulation of Na+, Cl- , K+ and Ca2+ ions in shoot and root was determined. At high level salt concentration, Cl- content in shoot and root increased. Result showed that sodium accumulation in sugarcane plants was more than potassium. By increasing salinity level, sodium uptake and its translocation to shoots increased reducing growth and dry matter yield of plants. With rising salt concentration from medium (0.5%) to high (0.75%), content of chloride in shoot and root of NCO-310 was constant showed that this cultivar had genetic ability to avoid Cl- uptake. CP82-1592 with lowest ratio of shoot / root chloride had minimum transport of Cl- to shoots. Also this cultivar had high content of Ca2+ in shoot and low Na+/Ca2+ ratio at all salinity levels. CP48-103 had low sodium in shoot and relatively low sodium in root. Thus it probably has genetic potential to avoid sodium uptake. At last, exclusion of Na+ and Cl- to older leaves and tillers was seen in CP82-1592 and CP72-2086 cultivars. According to results, to avoid once of absorption and transport, and exclusion of harmful Na+ and Cl- ions were mechanisms that could be used in salinity tolerance of sugarcane.
A. Moshgeli , J. Pourreza, A. Samie,
Volume 12, Issue 43 (4-2008)
Abstract
This experiment was conducted to determine the phosphorus relative bioavailability of eight samples of dicalcium phosphate. Bioavailability of Samples of dicalcium phosphate was evaluated and their effects on performance of laying hens were investigated. Commercial samples of Dicalcium Phosphate were provided from the following manufacturers: Iran Phosphate, Partove Bashash, Godaze, Poya Khojaste, Dan Razy Kimia, Phosphore Iran, Golbar Shimi and Dan Avar. The Parameters measured were shell strength, shell thickness, shell ash percentage, shell percentage, shell calcium and phosphorus percentage, Haugh unit, egg weight, egg production, egg output, feed consumption, feed conversion ratio, tibial ash, and tibial calcium and phosphorus. One hundred and six, and 36 weeks old white Leghorn hens, from strain Hi-line W-36, were randomly allocated to 8 dietary treatments and 4 blocks in a completely randomized block design. The experiment lasted for 3 months, starting in the 36th week and ended in the 48week of age. Shell thickness, shell ash percentage, shell percentage, feed consumption, tibial ash and tibial calcium percentage were significantly different (P< 0.05) among treatments. Effect of experimental period on shell calcium and phosphorus percentage, egg weight, egg production, feed consumption, egg output was significant (P< 0.05). Relative bioavailability of samples ranged from 85 to 105.7%. Overall, samples of Phosphate Iran (F) were considered most effective with regard to relative bioavailability and performance.
K. Rostami, M. R. Mosaddeghi, A. A. Mahboubi, A. A. Safari Sinegani ,
Volume 12, Issue 44 (7-2008)
Abstract
Transport and filtering of pathogenic bacteria through porous media and groundwater resources are important and، therefore the effect of various factors on bacteria transport and filtering has been given a great attention nowadays. In this study، effects of calcium sulfate and carbonate on Psedomonas fluorescens filtration and filtering parameters were investigated in saturated sand columns under steady-state flow. The calcium carbonate levels included 0، 5، 10 and 20 %w/w and calcium sulfate levels consisted of 0، 5 and 10 % w/w which were thoroughly mixed with sand (0.15-0.25 mm). The experiment was considered factorial in completely randomized design with three replicates. The treated sands were poured into pyrex cylinders with length of 20 cm and diameter of 7 cm. Then، steady-state saturated flow with constant flux was applied to the columns. When the steady-state flow was established، the bacteria suspension with concentration of 106 CFU cm-3 (C0) was injected as step input into the columns. The leaching then was continued up to 5 times of pore volume (PV). The effluent concentration of the bacteria (C) was measured at 0.25 PV intervals. Then، the sand columns were divided into 0-5، 5-10، 10-15 and 15-20 cm layers in order to measure the filtered bacteria in each layer. The results showed that the effects of calcium carbonate on retaining of the bacteria in the 5-10 and 10-15 cm layers were significant at 1% level. It was significant at 5% for the 15-20 cm layer. The effect of calcium sulfate was also significant at 5% for the 10-15 cm and 15-20 cm layers. The interactive effects of treatments on bacteria adsorption was significant for the 5-10، 10-15 and 15-20 cm layers. The retained concentration profile and the filtration coefficient were significantly affected by the treatments، showing higher bacteria adsorption at lower depths and predominance of physical filtering. The results showed the high filtering capacity of carbonate and sulfate minerals which could ultimately reduce bacteria transport in saturated porous media towards groundwater resources.
A. Khazaei, M.r. Mosaddeghi, A.a. Mahboubi,
Volume 12, Issue 44 (7-2008)
Abstract
Soil physical and chemical properties, and test conditions might affect soil structural stability. In this study, the effects of test conditions as well as intrinsic soil properties on structural stability were investigated for selected soils from Hamedan Province. Mean weight diameter (MWD) and tensile strength (Y) of aggregates were determined by wet sieving method and indirect Brazilian test, respectively. The soil samples were pre-wetted slowly to matric suction of 200 kPa before the wet sieving. The pre-wetted samples were wet-sieved for 5, 10 and 15 min in order to simulate different hydro-mechanical stresses imposed on soil structure. Tensile strength of soil aggregates were also measured at air-dry and 500 kPa matric suction conditions. Short duration shaking (i.e. 5 min) could effectively discriminate the Hamedan soils in terms of structural stability due to their fairly low aggregate stabilities. The soil organic matter content had the highest impact on MWD followed by both clay and CaCO3 content. The same was true for the Y values i.e. OM played the highest role in mechanical strength of soil aggregates. The highest coefficient of determination (R2) was obtained between Y and the intrinsic soil properties for matric suction of 500 kPa. The organic matter content had an important role in water and mechanically stable soil aggregates. The results indicated that short-duration wet sieving (i.e. 5 min) and measurements of tensile strength at matric suction of 500 kPa could be recommended for aggregate stability assessment in Hamedan soils