Showing 1573 results for on
M. Mostajeran, M. A. Edriss, R. Ebadi, G. H. Tahmasebi,
Volume 4, Issue 1 (4-2000)
Abstract
In order to estimate the heritability of morphological characters of worker honey bee and honey yield, 30 queen-mothers were selected randomly from the apiary of Research Center of Animal Science and Natural Resources in Isfahan Province. From each queen-mother, five queen-daughters were reared and introduced to equalize colonies after natural mating of queens. Summer honey yield was measured, while fall honey production was calculated from area of sealed honey combs. The total honey was calculated by adding summer honey production to fall honey production. Morphological characters were measured under a stereo-dissecting microscope fitted with a calibrated micrometer reticle according to Ruttners method (1985).
Heritabilities were estimated by intraclass correlation method. Heritabilities of summer, fall and total yearly honey yields were estimated to be 0.64, 0.51 and 0.30, respectively. Estimates of heritability of morphological characters for probscis length, tibia length, femur length, metatarsus length, metatarsus width, forewing length, forewing width, cubital index, hindwing length and number of hamuli were 0.64±0.08, 0.45±0.07, 0.50±0.07, 0.47±0.07, 0.33±0.06, 0.42±0.06, 0.89±0.10, 0.5±0.07, 0.94±0.10 and 0.45±0.07, respectively. It could be concluded that in order to increase honey yield in either season (summer or fall), selection must be based on the amount of honey yield in the corresponding season. Thus, heritabilities of forewing and hindwing lengths were high selection according to these morphological characters would, therefore, change the size of these characters.
S.s. Eslamian, V. Salimi, S. Chavoshi,
Volume 4, Issue 2 (7-2000)
Abstract
Peak discharge is one of the basic parameters in the design of hydraulic structures. There are various methods for peak discharge determination. Regional flood frequency analysis is based on physical, climatological and hydrological characteristics of basins. The objective of this study is to examine different models for the estimation of quantiles for some catchments in western Iran (namely: Gharehsoo, Gamasiab, Kashkan, Seimareh, Sezar and Abshineh) for which only maximum daily mean discharge data exist. In this research, peak and maximum daily mean discharges for 11 stream gauging stations were collected for a 21-year period. The ratio of these two discharges (R) and mean and standard deviations of peak discharges and maximum daily mean discharges were computed. Catchment characteristics including catchment area, catchment perimeter, main channel length, mean elevation, mean slope equivalent rectangle length, circular ratio, Gravelius coefficient, drainage density, time of concentration, relief ratio and diameter of the circle having equal area with the catchment were computed. Linear regression analysis was performed between independent variables of the catchments and mean standard deviation of the parameter “R” to develop a relation. The results of this study can be applied to the estimation of extreme flow values for non-recording stream gauging stations (daily reading sites).
A. Hassanli, A. Sepaskhah,
Volume 4, Issue 2 (7-2000)
Abstract
In this study, seven citrus gardens in different parts of Darab were chosen to evaluate the drip irrigation systems. The evaluation process was based on the Merriam and Keller’s model (1978). Besides the evaluation of drip irrigation systems, the water requirement of citrus was estimated using four models including Blany-Criddle modified by FAO, Hargrive-Samani, Pan Evaporation and Solomon-Kodama model. On the basis of the results obtained by Hargrive-Samani with 1296 mm annual water requirements, a comparison was made between irrigation with existing systems and irrigation under favorable and desired conditions.
The results from field measurements indicate a considerable reduction in the emitter discharges. The low pressure and emitter clogging could be two major reasons for the problem. Low pressure at head control, topography, head losses and also using no filter(s) or unefficient filters are the main reasons for the reduction. In some gardens, overirrigation even up to 2.5 times of water requirement was practiced by using extra emitters and increased irrigation times. Overirrigation causes considerable water losses through deep percolation and in reased overwetting area.
Field measurements indicated a good emission uniformity (EU) for the fields with overirrigation. EU in chosen fields varied from 40 to 91%, AELQ varied from 31 to 82% (poor to good) and PELQ varied from 36 to 82%. This study showed that most farmers are not familiar with plant water requirements. The fields with efficient filtration due to using extra emitters per plant are mainly overirrigated. But fields without any filter of unefficient filters are not irrigated sufficiently. The very high manufacturing variation coefficient of IEM emitters (Cv=0.22), which are widely used in Darab, causes a design emission uniformity of 55%.
I. Malek Mohammadi, A. Shafii Alavijeh,
Volume 4, Issue 2 (7-2000)
Abstract
Mutual understanding among officials and followers has been a point of concern in behavioral management. Natural resources extension which, from the very first step, is concerned with the exploration of practical problems is in serious need of an atmosphere of mutual understanding between agents and clientele. In this research, attention was drawn toward the measurement of mutual understanding between executives and nomads regarding nomads’ problems in utilizing natural resources and breeding cattle in Isfahan Province. For this purpose, initially, understanding between nomads and natural resources administrators (extension agents and specialists) regarding their respective problems were measured and compared. The research population of the study consisted of two groups. The first, involved 32 administrators, extension agents and specialists, and the second, 75 nomad families. Two different questionnaires were developed for the study as research instruments in which 52 items regarding nomad problems were included. Each part of the population was asked to rank the items accordingly. Then, some nonparametric tests such as Kruscall Wallis and Mann Whitny U tests were applied to compare the mean rank for each item within and between the two groups.
Results showed that the administrators and nomads had different attitudes in only two of the 52 items. Administrators had no statistically significant different attitude in 52 problems. Eliminating the discriminating items, the attitudes in only two groups were compared and results showed that they had no significant difference in the remaining 48 items. Therefore, extension agents can follow these problems based on their mean rank priority in their developmental projects. This method of data reduction and understanding field constraints can be applied to the studies dealing with planning agricultural and/or natural resources development projects through extension education.
M. Ahmadpour Borazjani, G.r. Soltani,
Volume 4, Issue 2 (7-2000)
Abstract
Marine products are currently important in Iran due to the following reasons: 1) aquatics are recognized as safe and healthy food by food scientists 2) because of low dependence of fishing technology on foreign resources, they are more reliable sources for protein and food security. Therefore, it is important to increase labor productivity using advanced fishing technology under a sustainable fishery management policy. In general, the prevailing methods of fishing in the southern coasts of Iran can be classified into three groups based on the level of technology and the length of journey made: traditional, semi-industrial, and industrial. In this study, labor productivity in the traditional and semi-industrial groups were compared using data obtained from a sample of 35 fishermen in Bushehr Province. To determine the marginal and average labor productivities, transcendental production functions were estimated for fish and shrimp, separately. The findings indicated that the marginal and average productivities of labor in semi-industrial fishing were significantly higher than in traditional fishing.
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.
A. Eghtedary Naeeny, H. Ghadiri,
Volume 4, Issue 2 (7-2000)
Abstract
In order to find the critical period of weed control, the best time of weed control beginning (i.e. herbicide application time), and the length of weed control period (i.e. herbicide persistency) in corn, field experiments were conducted in Bajgah and Kooshkak in Fars Province in 1995 using a randomized complete block design with 14 treatments and four replications. Treatments consisted of different times of weed control beginnings (20, 30, 40, and 50 days after corn emergence), different duration of weed control periods (10, 20, and 30 days), a weedy check, and a weed-free check during the period of corn growth.
In Kooshkak, a 10-day duration of weed control period had significantly lower corn yields than 20 and 30-day periods. In Bajgah, a 10-day weed control period had significantly lower corn yields than a 30-day period. Time of weed control beginning was not significant at both locations however, the interaction between beginning time and the duration period of weed control was significant. It appears in both locations that a minimum 20-day control period at the initial stages of corn and weed growth, and a minimum 30-day control period before corn pollination are necessary to prevent corn yield losses. In order to prevent corn leaf area decline at both locations, a 20-day weed control period until 40 days after crop emergence is necessary.
M.r. Khajehpour, F. Seyedi,
Volume 4, Issue 2 (7-2000)
Abstract
Obtaining high seed and oil yields of sunflower requires coincidence of vegetative and reproductive stages of growth of the plant with suitable environmental conditions via selecting appropriate planting date. Since the suitable date of planting for sunflower cultivars under Isfahan environmental conditions was not determined, this experiment was conducted in 1996 at the Agricultural Research Station, Isfahan University of Technology. In this study, five dates of planting (April 27, May 12 and 27 and June 12 and 29) and three open pollinated sunflower cultivars (Record, Vnimik 8931 and Armavirec) were evaluated using a randomized complete block design with split-plot layout in three replications. Date of planting was considered as the main plot and cultivars were randomized in the sub-plots.
Number of seeds per head (SH), l000-seed weight (SW), seed oil percent (SOP) and, consequently, yields of oil (OY) and seed (SY) were significantly reduced as planting was delayed. Reduction in these traits were considered to be related to the coincidence of vegetative and reproductive growth stages with higher temperatures prevailing at later plantings. Vnimik 8931 had higher SH and SW, and thus produced higher SY. This cultivar had lower SOP than Record, but produced higher OY than Record due to its higher SY. Armavirec was ranked the least for the measured traits, except for its SH that was slightly higher than that of Record. SH was the most contributing trait to the increase in SY, and SY was the most determining trait for the increase in OY. Date of planting by cultivar interactions for SH, SY and OY were significant. Nevertheless, the highest amount of the measured traits were obtained with Vnimik 8931 at the first planting date.
S. Zomorrodi, R. Shokrani, M. Shahedi, S. Dokhani,
Volume 4, Issue 2 (7-2000)
Abstract
The esterification process causes some desirable changes in physicochemical properties of fat by exchanging the acyl groups in triglyceride molecules. The aim of this study was to produce a suitable edible fat for industrial and home uses. In this study a mixture of 60 percent soybean oil and 40 percent edible tallow were inter-esterified, using 0.5 percent sodium methylate or ethylate as catalyst. The results obtained for solid fat contents and melting points indicated that the process of inter-esterification was accomplished in 30 minutes at 90°C. It was also observed that sodium methylate and. ethylate had similar effects on physical and chemical characteristics of the esterified blend. Iodine and saponification values indicated that the esterification process did not have any considerable effect on the degree of unsaturation or molecular weight of fatty acids. The peroxide values showed that the processing condition did not produce any peroxide. The esterified blend contained 1.10 percent trans fatty acids, which were originally present in the tallow. It is concluded that interesterification of soybean oil and edible beef tallow can be used as an alternative method to hydrogenation to produce a suitable plastic fat with low levels of trans fatty acids for the manufacture of different types of margarines and fats for home uses.
B. Mostafazadeh, M. Farzamnia,
Volume 4, Issue 3 (10-2000)
Abstract
In this research, the hydraulic behavior of furrow irrigation was investigated under cut-back, Walker-Skogerboe and conventional methods at the three experimental farms of Lavark, Shervedan, and Isfahan University of Technology for three irrigation events. In each farm, data were collected for each of the above methods with at least three replications including furrow shape, furrow length, furrow slope, soil texture, advance and furrow inflow and outflow.
The parameters of Kostiakov-Lewis infiltration function were determined using the volume balance method. The deep percolation ratio, runoff ratio and application efficiency were then computed.
The results showed that deep percolation ratio was higher in the cut-back method as compared to the Walker-Skogerboe method (18.6% as compared to 13.7%) and the runoff ratio was less in the cut-back method as compared to those in the Walker-Skogerboe and conventional methods (12.4% as compared to 16 and 20.6%, respectively). The effect of the two parameters of deep percolation ratio and runoff ratio caused, in general, the application efficiency to be less in the conventional method than those in the cut-back and Walker-Skogerboe methods (42.7% as compared to 69 and 70%, respectively). In general, the cut-back method had a higher application efficiency in heavy texture soils as compared to light texture soils (73.9% as compared to 51.2%).
M. Kalbasi, S.f. Mousavi,
Volume 4, Issue 3 (10-2000)
Abstract
Life in central Iran depends on the Zayandehrood river, making the preservation of its quality important. Salinization and pollution of the flow as a result of different organic and inorganic pollutants create serious threats to the environment and to the agricultural activities in the region. Although the role of the main drains discharged into the Zayandehrood in changing its quality is well known, little information is available on the volume and quality of the discharged drains. The purpose of this research was to study the quantity and quality of three main drains (Zoab-Ahan, Rudasht and Segzi) discharging into the Zayandehrood, Monthly samples were taken from each drain and their chemical properties were measured in 1998. The discharge rates were also measured simultaneously at sections near the discharge points.
The results showed that all three drains were alkaline and, therefore, had no negative effects on the pH of the river flow. Mean annual EC of Zoab-Ahan, Rudasht and Segzi drains were 5.56, 27.18 and 42.41 dS/m, respectively, and the salt loads discharged into the river by these drains were 39258.4, 37672.9 and 259781.2 ton/year, respectively. Annual mean N concentrations were 4.49, 3.92 and 4.18 mg/L and annual mean P concentrations were 0.26, 0.16 and 0.12 mg/L in the drains, respectively. The most important effect of the drains on the Zayandehrood was salinization, especially in the lower parts of the river. The increase in soluble salt contents of the river after Segzi drain discharge was so high that it made the water thereafter unusable for any purpose.
J. Torkamani,
Volume 4, Issue 3 (10-2000)
Abstract
The main objective of the present study was to investigate the production and marketing of Iranian saffron. About 99% of Iranian saffron is produced in Khorasan Province. Therefore, Khorasan was selected for the current study. Data were collected through the stratified random sampling method from 232 saffron producers in Torbat Heidarieh, Ghaenat and Gonabad regions through interviews in fall 1999. The production functions of saffron were estimated by using transcendental forms for the three study regions. Technical efficiencies for saffron producers were estimated using transcendental stochastic frontier production functions. Finally, wholesale, retail and marketing margins as well as marketing efficiency were estimated.
The results of the current study revealed that farmers were not using some of the inputs optimally. Study of the technical efficiency of saffron growers indicated that there was a considerable possibility of increasing production by increasing farmers’ efficiencies. The average of wholesale, retail and marketing margins of one kilogram of saffron were estimated to be 483, 410 and 893 thousand Rials, respectively, in the three study regions. Also, marketing efficiency was calculated at 155%. Finally, a marketing channel as a part of marketing strategy was proposed for Iranian saffron.
A.a. Ehsanpour, M. Jones,
Volume 4, Issue 3 (10-2000)
Abstract
Potato is a valuable plant as a source of nutrition and as an industrial product. The modification and breeding of potato plants are very difficult, or even impossible, via the conventional plant breeding programs. However, plant biotechnology and tissue culture are reliable methods which can produce plant material for gene transformation using Agrobacterium as a vector. In this study, one-, two-, and three-step methods of plant regeneration from stem culture of potato cv. Delaware were tested. Among these only the one-step procedure using TDZ, a synthetic cytokinin, was the best for rapid plant regeneration. In this culture medium, several shoot buds and shoots were regenerated from stem culture, while the other methods using a culture medium supplemented with BAP, NAA, zeatin, 2ip, IAA produced white and green callus. Morphology and chromosome number of all regenerated plants were similar to the original plants. The results showed that the regeneration system was suitable for cv. Delaware and that the culture conditions prevented genetic variation of the regenerated plants.
A. Arzani,
Volume 4, Issue 3 (10-2000)
Abstract
Knowledge of the effects of row spacings and seeding rates on dual-purpose forage and seed production of an annual legume crop is essential for its proper agronomical exploitation. In this study, the effects of various row spacings and seeding rates on dry matter and seed yield in berseem clover (Trifolium alexandrinum L.) were evaluated in two consecutive years. The experimental design was a split-plot with four row spacings as main plot treatments in a randomized complete block design with four replications, and five seeding rates were allocated to subplots.
Combined analysis of variance of the two-year data showed that both row spacings and seeding rates influenced dry matter yield (DM), seed yield, plant height, 1000-seed weight and harvest index. Years, as well as two- and three-factor interactions did not affect the seed yield whereas row spacing × seeding rate, and year × seeding rate significantly affected the DM. The mean comparisons indicated that row spacings of 30 and 45 cm produced the highest DM of 3912.2 and 3900 kg/ha 45 and 60 cm spacings showed the highest seed yield of 1045.4 and 1093.3 kg/ha, respectively. 24 and 20 kg/ha seeding rates ranked the best in giving 1244.7 and 1223 kg/ha seed yield, respectively. The seeding rate of 16 kg/ha in the first year and 20 kg/ha in the second year produced the highest DM yield with means of 3837.5 and 3875.3 kg/ha, respectively. Regarding the dual-purpose of forage and seed production in berseem clover, 20 kg/ha seeding rate at 45 cm row spacing can be recommended for Isfahan region and for other comparable environmental conditions.
M. Shahedi, B. Mansouri,
Volume 4, Issue 3 (10-2000)
Abstract
Macaroni is a food product generally considered as one of the paste products. These products are produced from semolina that is, in turn, produced through special processing of milled durum wheat. In order to examine the effect of α-amylase on macaroni quality, three cultivars, namely Yavarous, Zardak and Altar 84, were chosen from each of which some wheat sprouts were prepared and mixed with unsprouted samples to obtain three ranges of falling numbers of 500-1000, 300-350 and 150-200 seconds.
The results from this study specified that the active presence of α-amylase in the samples reduced cooking time and colouring of the macaroni, while small amounts of the enzyme improved the breakage and modulus of elasticity of the samples. The α-amylase enzyme showed no effect on the colour of semolina and the macaroni stickiness.
S.k. Allameh Fani, N. Mahboobi Soofiani, J. Pourreza, A. Esteki,
Volume 4, Issue 3 (10-2000)
Abstract
The present experiment evaluates the effects of some carbohydrate sources (corn, barley and millet) and the replacement of corn with different levels (0, 25, 50, 75, 100%) of barley and millet on the performance of common carp (Cyprinus carpio L.). In a completely randomized block design, 540 grower fish with an average body weight of 70 gr, were divided into 27 groups, 20 fish per group. Nine different diets were used and each diet was assigned to triplicate groups of fish for eight weeks.
Analyses of data showed that the replacement of corn by barley and millet resulted in a higher weight gain. The highest and lowest weight gains were observed with diets having 50 percent barley and 100 percent millet substitutions, respectively, although the differences with the control diet were not significant. Diets with 50 and 100 percent barley for corn substitutions showed a greater specific growth rate (SGR). As for the food conversion ratio (FCR), all the diets having barley and millet, irrespective of substitution levels, showed a better FCR relative to the control diet. However, the diet with 100 percent barley substitution had the best FCR, but no significant differences were observed (P>0.05) with the control diet. In general, the performance of barley was better than that of corn and millet, and millet was relatively better than corn. However, these results indicate that barley and millet can be suitable replacements for imported corn in diets used for common carp.
B. Hatami, K. Zibai,
Volume 4, Issue 3 (10-2000)
Abstract
The interference of biological agents may cause behaviors such as interspecific predation, reducing their efficiencies. The interspecific predation of lacewing, Chrysoperla carnea (Steph.) and ladybeetle, Hippodamia variegata (Goeze) was investigated in the presence and absence of prey, Aphis gossypii Glover under laboratory conditions.
In the presence and absence of prey, the larvae of lacewing fed on eggs, larvae, pupae and adults of ladybeetle and the larvae and adults of ladybeetle fed on eggs and larvae of lacewing. Presence of prey reduced the rate of feeding significantly. Feeding of lacewing larvae on ladybeetle eggs was higher than the feeding of ladybeetle larvae and adults on lacewing eggs. This is probably due to the stalk of lacewing eggs. The 1st larval instar of lacewing was dominant to that of ladybeetle, so were 2nd larval instar of lacewing to the 1st and 2nd larval instars of ladybeetle and 3rd larval instar of lacewing to all larval instars and adults of ladybeetle. Third larval instar of ladybeetle was dominant to the 1st larval instar of lacewing, and 4th larval instar and adult of ladybeetle to the 1st and 2nd larval instars of lacewing. The 2nd and 3rd larval instars of lacewing fed on pupa of ladybeetle but larval feeding of ladybeetle was not observed on lacewing pupa. This was probably related to lacewing pupa covered by a cocoon.
M. Nasr-Esfahani, A. Akhiani, H. Fatemi, H. Hassan-Pour,
Volume 4, Issue 3 (10-2000)
Abstract
Solarization of field soil through mulching with transparent polyethylene sheets alone and in integration with farm yard manure (40 T/ha) and/or metalayl (25 kg/ha) during summer 1994-95 for five weeks in Isfahan resulted in an increase in temperature of 10 °C (± 1) and moisture preservation of up to 82%. Solarization effectively reduced foot-rot of cucumber (Phytophthora drechsleri) in the above treatments up to 88%, 96% and 95%, respectively.
Solarization, farm yard manure and their integration reduced the infection of Meloidogyne javanica up to 50%, 57% and 83% while plant parasitic nematodes were also reduced to 72%, 75% and 86%, respectively. The populations of free living nematodes increased only in farm yard manure and in integration with solarization by 30% and 53%, respectively.
Solarization effectively reduced the populations of almost all weeds by around 100%, except for Cyperus rotundus and Sonchus asper which were reduced by 59% and 44%, respectively.
A.a. Vali, M. Bassiri,
Volume 4, Issue 3 (10-2000)
Abstract
Artemisia is the major component of the vegetation of a large portion of arid lands in Iran. Determining the utilization rate is an essential element in the management of these rangelands. Methods of determining the utilization regime for woody plants and shrubs include clipping and weighing, reference unit, ocular estimate, twig length, branch diameter and production index. These methods were used in Chahlor winter range in Jarghoyeh, 250 Km southeast of Isfahan. Clipping and weighing is the most accurate although the most time-consuming method. In this research, means of utilization percentages obtained from the above methods were compared with the mean obtained from the clipping and weighing method using T-test.
Data obtained from reference unit, twig length, and branch diameter methods were not significantly different from those of clipping and weighing method (P>0.0l). Since reference unit was the least time-consuming among these methods, it was selected as a proper method of utilization measurement of Artemisia stands.
S.j. Khajeddin,
Volume 4, Issue 3 (10-2000)
Abstract
Plant communities of the Kolah-Ghazi National Park have been studied. The park with a wide diversity of fauna and flora species is located 36 Km south of Isfahan. 214 plant species were collected for the purposes of this study. Plant communities of the park are of an aridland vegetation type. Minimal areas of the plant communities were determined using nested plots technique. After studying the Species/Area curves, a l00-square-meter quadrat was employed to collect the cover and density data for each species. The cover data were analysed to determine plant communities using the ordination method.
Crown cover of the vegetation was found to be poor and varied from zero to a maximum of five percent in the park. The following species form the major plant communities in the park: Artemisia sieberi, Anabasis aphylla, Acantholimon spp., Cousinia piptocephala, Ebenus stellata, Pteropyrum aucheri & Scariola orientalis. The combination of these species with others forms plant communities and subcommunities. The overlapping of habitats makes mosaics which cause the formation of ecotones, thus increasing the diversity of the subcommunities in the park. Mesophytic plant communities are narrowly scattered along streams. Most of the plant communities are controlled by the adaphic factor while the biological factor has only a limited control. A Ficus spp. specimen was also collected from the mountainous region in the park which could be a new species or variety and requires further study.
