Showing 344 results for Ph
M. Vatankhah, M. A. Talebi, M. A. Edris,
Volume 11, Issue 41 (10-2007)
Abstract
In this study 5025 records from the Lori-Bakhtiari sheep stud were used to predict phenotypic, genetic and environmental change in ewe traits from 1989 to 2004. Best linear unbiased prediction (BLUP) of breeding values were estimated by Drivative Free Restricted Maximum Likelihood (DFREML) procedure using single and multi-trait animal model. Phenotypic, genetic and environmental trends were calculated by regressing of the average phenotypic values, predicted breeding values and environmental values in the year of ewe birth respectively. The estimated phenotypic trends were –0.1223 kg for ewe body weight, -0.0415 kg for greasy fleece weight, 0.6639% for conception rate, 0.0003 for number of lambs born per ewe lambing, 0.0094 for number of lambs weaned per ewe lambing, 0.0380 kg for total birth weight per ewe exposed and 0.4227 kg for total weaning weight per ewe exposed. The estimated genetic trends were 0.0603 kg, -0.0004 kg, 0.0183%, -0.0012, -0.0007, 0.0030 kg and 0.0211 kg from single trait analysis and 0.0549 kg, -0.0006 kg, 0.0089%, -0.0008, -0.0008, 0.0030 kg and 0.0230 kg respectively from multi-trait analysis. The estimated phenotypic and environmental trends were significant but genetic trends were not significant (P<0.05) for often traits.
S. E. Sadati, S. F. Emadian, H. Jalilvand, J. Mokhtari, M. Tabari,
Volume 11, Issue 41 (10-2007)
Abstract
The present research was conducted to find the influence of some topographic factors on distribution of large-leaved lime (Tilia platyphyllos Scop.) and its natural regeneration characteristics in "Vaz" forest (northern Iran). After identification of site and preparation of topography map, selective sampling method was carried out for tree inventory in plots. The sample plots were circular in 1000-m2 areas with at least 2-3 dominant lime trees in each. In the plots, altitude, slope gradient, direction, forest storey, tree type and natural regeneration were investigated. Results indicate that in this habitat the average diameter at breast height and height of Tilia platyphyllos is 36.9 cm and 23 m, respectively. Tilia platyphyllos prefers 1200-1400 m altitude, 75-100% slope gradient and northeastern to eastern directions and benefits from denser trees in these environments. It consists of some tree types together with Fagus orientalis, Carpinus betulus and Parrotia persica, whereas the dominant type is Tilia platyphyllos-Fagus orientalis. In most of tree types, lime occurs in the upperstorey. Natural regeneration of lime is often observed as sprout (coppice shoot).
S. Rajaee, H. A. Alikhani, F. Raiesi,
Volume 11, Issue 41 (10-2007)
Abstract
Azotobacter chroococcum is an important PGPR (Plant Growth Promoting Rhizobacteria) producing compounds needed for plant growth. The aim of this research was to study the effects of different native strains of Azotobacter chroococcum on growth and yield of wheat under greenhouse counditions. Seeds of spring wheat (Triticum aestivum L. var. Pishtaz) were inoculated with some Azotobacter chroococcum strains capable of producing IAA, HCN, sidrophore and fixing molecular nitrogen. The inoculation of wheat with those strains had a positive, significant effect on biological yield, seed protein percentage, thousand seed weight, leaf area, N, P, Fe and Zn uptake, in particular, by wheat. The increased growth of wheat was most likely due to the production of IAA and enhanced nitrogen fixation by inoculated strains. Some strains of Azotobacter chroococcum native to Chaharmahal va Bakhtiari are established as PGPR. Results also support the efficiency of Azotobacter chroococcum as an important biofertilizer in wheat cropping systems. The selected strains had a significant effect on wheat growth and yield, including biological yield and seed quality under greenhouse counditions. This beneficial effect of Azotobacter chroococcum on wheat is attributed mainly to IAA production and, to some extent to non symbiotic nitrogen fixation in the rhizosphere. So, these strains can potentially be used to improve wheat nutrition of micronutrients such as Fe and Zn, in particular.
M.r. Tadayon, Y. Emam,
Volume 11, Issue 42 (1-2008)
Abstract
Photosynthesis and wheat grain yield responses to supplemental irrigation with different amount of applied water under dryland conditions were investigated. Therefore, a two-year field experiment was conducted research farm of College of Agriculture, Shiraz University during 2004-2005. Five levels of irrigation including dryland conditions, irrigation at stem elongation, booting, flowering and grain filling were main plots and two wheat cultivars: Agosta and Fin-15 were subplots, and three rates of nitrogen including zero, 40 and 80 kgha-1 were sub sub-plots. The results showed that in both years, photosynthetic rate, stomatal conductance, substomatal CO2 concentration and transpiration rate, were significantly higher under irrigation at stem elongation stage compared to other supplemental irrigation treatments. In all of the four supplemental irrigation treatments, photosynthetic rate, stomatal conductance, substomatal CO2 concentration and transpiration rate decreased with decreasing the amount of applied water to each plot. In both years, the highest grain yield was obtained from supplemental irrigation at stem elongation stage, and the lowest yield was harvested at dryland conditions. The highest photosynthetic parameters, yield and yield components were obtained from interaction of supplemental irrigation at stem elongation stage × Fin-15 and 80 kg N ha-1 in both years. The supplemental irrigation in 2004 and 2005 increased the grain yield 200 and 221 percent, respectively, compared to dryland conditions. Thus, supplemental irrigation at sensitive stem elongation stage could affect significantly wheat grain yield of rainfed wheat cultivars and provision of adequate water for a supplemental irrigation at the appropriate growth stage could double the grain yield of rainfed wheat.
N. Mahdavi Arab, R. Ebadi, B. Hatami, K.h. Talebi Jahromi,
Volume 11, Issue 42 (1-2008)
Abstract
In order to evaluate insecticidal potential of some botanical extracts, a factorial experiment of complete randomized design with three replications on Callosobruchus maculatus was adopted for a pilot experiment in the laboratory. Plant extracts were prepared from 22 plants with three solvents (Methanol, Acetone and N-Hexane) with 30% concentration. Experiments were carried out at 25˚C and 70 ± 5% RH under 16: 8 (D: L) conditions. Each unit of experiment was a petri dish covered with a filter paper and 1.5 ml of each treatment solution was poured in it and 25 insects were released. Mortality was recorded after 36 hours. In this experiment, each plant extract with more than 50% mortality on C. maculaus was selected for further laboratory screening. In this stage of experiment methanolic leaf extract of Teucrium polium (with 55.04 percent mortality), hexane extract of Sonchus oleraceus (with 54.64 percent mortality), acetonic leaf extract of Calotropis procera (with 53.6 percent mortality), methanolic extract of Fumaria parviflora (with 52.7 percent mortality), methanolic extract of Capsicum annuum (with 50.04 percent mortality), and acetonic extract of Thymus vulgaris (with 50 percent mortality) were selected. After carring out the pilot experiment, the effective extracts with five concentrations of 15, 22.4, 33.5, 50.2 and 75% and one control were evaluated on the C. maculaus. This experiment also was designed in the laboratory as a factorial experiment of complete randomized design with three replications and mortality was recorded after 36 hours. In the highest concentration (75%), extract of Fumaria parviflora and extract of Thymus vulgaris (with 88.3% mortality) and extract of Sonchus oleraceus (with 78.3%) had higher and lower percentage of mortality resectively. The LC50 values of effective extracts were calculated for C. maculaus after 36 hours of treatment with plant extracts. The results showed that C. maculatus with LC50 = 126.27 µl/ml has highest sensitivity against extract of Fumaria parviflora and has lower sensitivity against extract of Sonchus oleraceus with LC50 = 370.09 µl/ml in comparison to other extracts. Amongst the tested concentrations of plant extracts, 5 plant extracts with the concentrations that had the higher mortality on C. maculaus, were selected for experiment on Laphigma exigua in greenhouse. This experiment was carried out with complete randomized design with four replications. The acetonic leaf extract of Calotropis procera (with 57.5 %) caused the highest mortality and acetonic extract of Thymus vulgaris (with 27.5 %) caused the lowest mortality on L. exigua in comparison to other extracts.
H. Khodaverdiloo, M. Homaee,
Volume 11, Issue 42 (1-2008)
Abstract
Phytoremediation is a new technology that employs plants to remediate contaminated soils. This method compared to those that involve the use of large scale energy consuming equipments is an inexpensive method. Phytoremediation models are useful tools to further understanding the governing processes and also to manage the contaminated soils. A thorough literature review indicates that very few models have been developed for phytoremediation due to the complexity of the phenomena. The objective of this study was to develop a simple model for phytoremediation of lead and cadmium. A new formulation of phytoremediation was established based on soil and plant responses to heavy metal pollution. A large quantity of a sandy loam soil was thoroughly mixed to ensure homogeneous different concentration levels by lead and cadmium. These contaminated soils were transferred to some plastic pots. Land Cress (Barbarea verna) and Spinach (Spinacia oleracea L.) seeds were germinated in pots containing 8 kg of contaminated soil. Plants were harvested at five time intervals. The concentrations of Pb and Cd in the plant and soil samples were digested by wet oxidation and 4 M Nitric acid digestion methods, respectively, and were determined by flame and graphite furnace atomic absorption spectrometry methods. Proposed models then were calibrated using the collected data and validated quantitatively. The results indicated that the soil adsorption isotherms followed a linear form for both Pb and Cd concentrations. The results also indicated that the phytoremediation rate of Pb by Land Cress and Spinach are first-order function of Pb concentration in soil. In contrast, a zero-order function of soil Cd contaminations was obtained. Combining these two results of soil and plant responses to Pb and Cd pollution, a simple model with reasonable performance was derived to predict the time needed for remediation of soil Pb (R2 > 0.98). However, in the case of Cd, the derived models appeared to be useful to make only some overall estimations of the remediation (R2≈0.70).
R. Dehghan, H. Shariatmadari, H. Khademi,
Volume 11, Issue 42 (1-2008)
Abstract
Studying soil phosphorus fractions is useful in understanding soil pedogenesis as well as soil fertility. In this reseach, 20 soil samples were taken from different depths of 0-30 and 30-60 cm of upper-slope, mid-slope and lower-slope positions of four toposequences in arid (Jei and Ziar in Isfahan) and semiarid (Farokhshahr and Shahrekord) regions. In each toposequence, the soil depth was relatively low at the upper-slope position and increased toward the lower-slope. The soils in upper-slope and mid-slope were under scarce native vegetation where the soil in lower-slope was under farming activities. Soil phosphorus (P) fractionation was carried out using sequential extraction. The total soil phosphorus was in the range of 302-1135 with an average of 715 mg/kg. About 65-89% of total phosphorus were inorganic, and 11-35% organic. The amount of inorganic and organic P in the soil samples was in the range of 204-897 with an average of 571, and 70-238 with an average of 114 mg/kg, respectively. The amount of total, inorganic and organic P increased from upper-slope toward the arable lands and decreased from topsoil to subsoil in all toposequences. In the studied soils, apatite ( Ca10-P ), aluminum phosphates(Al-P), octacalcium phosphates( Ca8-P ), iron phosphates (Fe-P), iron oxides occluded phosphates( OC-P ) and dicalcium phosphates( Ca2-P ) were the major constituents of the soil inorganic phosphates, respectively.
F.s. Biabanaki, A.r. Hosseinpur,
Volume 11, Issue 42 (1-2008)
Abstract
Phosphorus (P) after nitrogen limits agricultural production in most region of the world. Information about P release rate is limited in Hamadan soils. The objective of this research was to study P release in 10 soils from Hamadan province by successive extraction with 0.5 M NaHCO over a period of 1752 h and the correlation of P release characteristics with soil properties and corn plant (Zea mays) indices. The results showed that soil P release began with a fast initial reaction, followed by a slow secondary reaction until 1752 h. The amounts of soil P released after 1752 h ranged from 309 to 586 mg kg-1. The cumulative P release was evaluated by six kinetics equations. Statistical analysis showed that phosphorus release kinetics were described by parabolic diffusion law, first order and power function equations. The correlation study indicated that soil P release coefficients such as rate constant of first order, parabolic diffusion law, power function equations, P released after 168 and 1752 h were significantly correlated with some soil properties such as Olsen-P, calcium carbonate equivalent, sand and silt. The correlation studies between plant indices and constants of kinetics equation showed that rate constant of first order equation was not significantly correlated with plant indices. Equation constants of parabolic diffusion law, power function and P release after 1752 h were significantly correlated with plant indices. The results of this research indicated that release rate of P is different in soils and is an important factor in supplying available P to plants.
A. Taebi, K. Jeirani, A. Mirlohi, A.r. Zadeh Bafghi,
Volume 11, Issue 42 (1-2008)
Abstract
Some industrial processes, such as plating and gold mining, utilize cyanide, which entering in their effluents. Because cyanide compounds are toxic contaminants, the waste-containing cyanide must be treated before discharge in the environment. Several methods are available for cyanide removal or detoxification. Natural degradation, alkaline chlorination, and oxidation with hydrogen peroxide are the most common methods in full-scale plants. Because of technical and economical concerns related to these methods, biological treatment processes have recently come under consideration. In phytoremediation, plants potential for pollutant removal is used. The main objective of present study is to investigate feasibility and potential of phytoremediation of cyanide-polluted soils by non-woody plants. The experiments carried out in this study were a completely random factorial design procedure, with three replications. Three non-woody plants: sorghum (as a cyanogenic cereal plant) and fescues with and free of endophyte (as grasses), were examined. Analysis of variance of the data obtained on soil cyanide reduction and cyanide accumulation in plants showed that phytoremediation is a suitable technique for low concentration of cyanide-polluted soils. Besides, it was been found that sorghum has a better soil cyanide removal efficiency than fescues, so that a significant portion of soil cyanide will accumulate in sorghum tissues.
N. Sahebani , J. Zad , A. Sharifi-Tehrani , A. Kheiri ,
Volume 12, Issue 43 (4-2008)
Abstract
Polyphenol oxidase (PPO) activities were measured spectrophotometrically in tomato(Roma VF: resistant to Fusarium oxysporum f.sp. lycopersici and susceptible to Meloidogyne javanica) roots inoculated with nematode and fungi in four biological life stages of nematode. PPO specific activity showed a significant decrease in treatments (nematode + fungi) as compared with control plants. Results showed that nematode is able to change or suppress induction of this enzyme in spite of fungal induction. Nematode in all biological stages suppressed the induction of PPO activity in tomato roots but in young adult formation stage the suppression was higher than other life stages including giant cell formation, egg-laying and penetration. Native polyacrylamide gel revealed the presence of five isozymes of PPO with Rm values of 0.26, 0.31, 0.44, 0.50 and 0.63. Isoforms with Rm values of 0.26, 0.44, 0.50 and 0.53 showed significant changes in nematode + fungus inoculated tomato plants compared to plants inoculated with fungus alone. Based on the results obtained in this study, nematode infection resulted in suppression of tomato defenses against the fungi (as secondary pathogen) and intensified the fungal disease. Five PPO isoforms with Rm values of 0.26, 0.31, 0.44, 0.50 and 0.63 were shown in native polyacrylamide gel among which the isoform with Rm value of 0.31 had a thicker band in tomato plants inoculated with nematode or fungus alone. Two isoforms with Rm values of 0.44 and 0.53 in nematode-inoculated plants were similar to the corresponding bands in the healthy control. Isoforms with Rm values of 0.26, 0.44, 0.50 and 0.53 in nematode-fungus-inoculated tomato plants showed significant changes compared to plants inoculated with the fungus alone. Nematode infection of root tissue caused suppression of PPO specific activity and induced changes in PPO isoforms with Rm values of 0.26, 0.44, 0.50 and 0.63 more significantly than isoform 0.31.
N. Sahebani, N. Hadavi,
Volume 12, Issue 43 (4-2008)
Abstract
This research was conducted to study the effect of nematode (Meloidogyne javanica) on severity of tomato Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 1) and changes in Phenylalanine ammonia lyase (PAL) activity in split-root assays to show the possibility of systemic induced susceptibility caused by nematode to the fungus by local nematode infection. The results showed that the activity of nematode in one part of root confered susceptibility to Fusarium wilt in other part of the plant root and subsequently disease symptoms increased significantly in comparison to the control (without nematode inoculation). PAL specific activity showed a significant decrease in one half of split-root inoculated with fungus when the other half was inoculated with nematode as compared with the control (without nematode inoculation). Based on the results obtained in this study, nematode infection in one part of tomato plant root resulted in suppression of tomato defenses in all parts of the root, reduced tolerance or resistance to the fungus (as secondary pathogen) and intensified the fungal disease.
A. Sadeghi, F. Shahidi, S.a. Mortazavi, M. N. Mahalati, S.h.r. Beheshti,
Volume 12, Issue 43 (4-2008)
Abstract
The aim of this study was to use Alpha-amylase termamyl 2-x for maltodextrin production from corn starch and evaluate its industrial uses. Based on the results obtained in laboratory, this process was accomplished in pilot plant scale. The process included preparation of starch suspension, pH adjustment, addition of enzyme, heating under stirring, continuous control of DE and Brix, enzyme inactivation in adequate DE, separation of soluble sections by centrifuge and finally spray-drying of the maltodextrin liquid. In this investigation, the amount of DE at dry matter was calculated under three enzyme concentrations (0.2, 0.25 and 0.3 ml of Alpha-amylase termamyl 2-x per Kg of starch) and in three different hydrolysis temperatures (60, 65 and 70 ºC) at constant pH (6). A completely randomized design with factorial arrangement and 5 replications was conducted. To study the relationship between DE and different parameters, multiple linear regression was used. Finally, for approximation of DE (based on enzyme concentrations, temperatures and hydrolysis times) a regression model was used. The results from different enzyme dosages at the same temperature and time of hydrolysis differed significantly (p≤ 0.05). Meanwhile, the best enzyme concentration and hydrolysis temperature for maltodextrin (high DE) production after 300 minutes were 0.25 ml of enzyme per kg of starch and 70 ºC, respectively. In these conditions, the least residual starch concentration and residual Alpha-amylase activity were observed.
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. Nazem, Y. Rozbehan, S.a. Shodjaosadati,
Volume 12, Issue 43 (4-2008)
Abstract
The nutritive values of lemon and orange pulps treated with Neurospora sitophila fungus were assessed by chemical composition, in vitro digestibility, in situ (dry matter and nitrogen) degradation methods. The obtained data from the untreated and treated pulps with fungi were compared using t-test. Mean values of the chemical analysis for crude protein, ash, organic mater, NDF and ADF for untreated lemon pulp were 6.3, 6.2, 93.8, 21.3 and 17.9 for treated lemon pulp 25.1, 10.6, 89.4, 12.7 and 6.8 for untreated orange pulp 6.8, 6.5, 94.5, 26.1 and 20.3 and for treated orange pulp 23.2, 8.1, 91.9, 18.5 and 15, respectively. In all cases, a significant difference (P<0.01) between untreated pulp and treated pulp of lemon and orange was observed. Digestibility coefficient of DM, OM and DOMD of untreated lemon pulp were 79.3, 80.5 and 75.5 treated lemon pulp were 91.4, 93.5 and 83.5 untreated orange pulp were 81.5, 82.8 and 78.2% and treated orange pulp were 91.2, 94.5 and 86.9%, respectively. The digestibility coefficient for the treated pulps (lemon and orange) was significantly (P<0.01) higher than those untreated. The percentages of DM degradability of pulps in nylon bag after 48 hours of incubation with the out-flow rate of 0.05 were as follows: 66.3 for untreated lemon 75.2 for treated lemon 68.7 for untreated orange and 75.5 for treated orange. The DM degradability for the treated pulps (lemon and orange) was significantly (P<0.01) higher than those untreated. The effective degradability of protein after 48 hours of incubation in nylon bag with the out-flow rate of 0.05 was as follows: 12.1 for untreated lemon 73.7 for treated lemon 14.8 for untreated orange and 77.8 for treated orange. The effective degradability of protein for the treated pulps (lemon and orange) was significantly (P<0.01) higher than those untreated. In conclusion, treating citrus pulps with Neurospora sitophila increased the concentration of CP, digestibility coefficients and protein degradability.
M.r. Ghanbarpour , M. Teimouri, S.h. Gholami,
Volume 12, Issue 44 (7-2008)
Abstract
Estimating the volume of groundwater contribution to runoff within a watershed is one of the most important subjects in water resources management and hydrology. In this paper, groundwater contribution to total runoff as a base flow index was estimated using hydrograph separation in six stream gauging stations in southwest of Iran. The major objective of this research is to distinguish the most suitable automated hydrograph separation and base flow estimation method. Conventional automated hydrograph separation methods including local minimum and recursive digital filter with the parameter of 0.9 to 0.975 were compared with recession analysis numerically and graphically. The results showed that recursive digital filter with the parameter of 0.925 is the most accurate method to estimate base flow in the studied watersheds. This research also indicated that the base flow index estimated through the selected method varies from 0.79 to 0.88 in the study area.
A.a. Besalatpour, M.a. Hajabbasi, A.h. Khoshgoftarmanesh , M. Afyuni1,
Volume 12, Issue 44 (7-2008)
Abstract
Total petroleum hydrocarbon (TPH) contaminations in soils may be toxic to human, plants and cause groundwater contamination. To achieve maximum TpH- reduction and to establish successfull stable vegetation cover in phytoremediation method, various criteria must be considered to choose the plants carefully. In this study, germination and subsequent growth of seven plants were tested in three soils with different petroleum contamination levels. Contamination treatments consisted of C0 (uncontaminated soil), C1 (1:1 w/w, uncontaminated: contaminated soil) and C2 (1:3 w/w, uncontaminated: contaminated soil). The experimental design was completely randomized split plots with three replications per treatment. The results showed that the presence of TPH in the soil had no effect on seed germination of agropyron, white clover, sunflower and safflower although canola seedlings were sensitive to these compounds and failed to produce dry matter yield (DMY) at the end of trial period. In contrast, seed germination of canola, puccenillia and tall fescue decreased in the petroleum contaminated soils. No reduction was found in DMY of puccenillia in contaminated soils (C1 and C2 treatments) compared to control however, the presence of TPH proportional to the contamination levels, decreased dry weight of sunflower and safflower. This reduction in growth and dry weight for tall fescue and agropyron was also observed in C2 compared to C1 treatment. Therefore, it seems that though agropyron, white clover, sunflower and safflower germinated well and the presence of TPHs in the soil treatments had no effect on their seed germination, they grew poorly. In contrast, grasses had poor seed germination but their subsequent growth and establishment in the contaminated soils was acceptable for subsequent phytoremediation trials.
N. Toomanian, H. Khademi , A. Jalalian,
Volume 12, Issue 44 (7-2008)
Abstract
Determination of landscape evolution is useful to well understand the physical environment and it also enables us to conduct the soil related studies. The objective of this study was to establish the historic evolution of Zayandeh-rud Valley from late Tertiary to Quaternary. To achieve this objective, the spatial structure of a representative area of Zayandeh-rud Valley in three dimensions was examined. Responsible geologic and geomorphic processes of landscape formation were determined and inherited records and evidences of changes in soil development were investigated. The inherited foot marks and different analyses proved that following the Zayandeh-rud River formation, from Miocene to present time, the following processes and events have occurred during valley formation pathway: 1- formation of old gypsiferous gravelly alluviums, 2- lagoon formation, the change in the river pathway, 3- playa formation, 4- river terrace deposition and 5- starting of wind erosion.
A. Jafari, H. Shariatmadari, H. Khademi, Y. Rezainejad,
Volume 12, Issue 44 (7-2008)
Abstract
Mineralogy is one of the most influential soil properties that change from upper- to lower slope positions, depending on the climate differences. Such changes affect soil properties such as phosphorus sorption and desorption processes differently. Therefore, this study was carried out to investigate the clay mineralogy of soils in four toposequences from arid (Isfahan) and semiarid (Chaharmahal Bakhtiari) regions and its effect on soil P release. The soils of three points on each toposequence were sampled as the upper-slope mainly containing parent materials the mid-slope, non-arable lands and the lower-slope, arable lands. Some of soil properties such as clay minerals were determined. Also, trend of P release parameters was studied in four toposequences. Results showed that the amount of clay, cation exchange capacity (CEC), electrical conductivity (EC), and pH of the soils increase down the slope in all toposequences. X-ray diffractograms showed that kaolinite and illite in upper slope and smectite and chlorite in lower slope were the predominant clays. Among the kinetic models examined based on their determination coefficient and standard error, the Elovich equation was chosen to describe the P release kinetics in studied soils. The trend of P desorption rate along the arid toposequences was in the following order: upper-slope < mid-slope < lower-slope. Furthermore, the rate of P desorption in soils of the semiarid toposequences was higher than arid toposequences. Regarding the trend of P rate parameters along the toposequences, it could be concluded that P release rate and the soil capacity to supply P for plants increase toward lower slope.
H. Yosef-Zadeh, M. Tabari, K. Spahbodi, Gh. Jalali,
Volume 12, Issue 44 (7-2008)
Abstract
In order to predict Caucasian maple (Acer velutinum Boiss. ) seedling growth based on nursery Orimel, Eighty six one year old seedlings located at 1550 meters above sea level in Sari, north of Iran were randomly selected. Collar diameter, height, leaf area, photosynthesis area and leaf area/leaf weight ratio were determined. Then multivariate regression models between leaf characteristics and growth characteristic were drawn. The results indicated that number of leaves and photosynthesis area can estimate the height growth of a seedling. Also, mentioned characteristics of leaf can estimate the biomass of stem as a well as growth characteristics. According to the correlation between growth characteristics and leaf characteristics, it would be concluded that the photosynthesis area of leaf can be suitable for early selection of seedling for reforestation. Also, this result shows the importance of increasing the establishment and growth of maple seedlings in plantation areas.
M. Khodagholi, Z. Eskandari, M. Saeidfar, S. Chavoshi,
Volume 12, Issue 44 (7-2008)
Abstract
The effect of nitrogen and phosphorous fertilization on range species production was studied using factor combination method as factorial with 3 blocks and 12 treatments. Nitrogen in 4 levels of 0،25،50 and 75 kg N/ha and phosphorus in 3 rates of 0،30 and 60 kg N/ha were used. Results indicated no significant difference between nitrogen rates in different growth forms of grass, bush and Eurotia ceratoides. Nitrogen in 75 kg/ha rates caused an increase of 40 and 106% in grass and Eurotia production, respectively. The maximum rate of production was seen in N50 with 100 percent increase compared to N0. Moreover, no significant difference in phosphor rates of leguminous and grass was observed. P 60 kg caused 500 and 56 % increase in leguminous and grass production, respectively.
