Year:2004 | Volume:10 | Issue:1|Papers Count:10

Different wheat aphid species in Varamin region were identified and their abundance and population structure and fluctuations were investigated during 1999-2001. The results indicated that there were mainly five wheat aphid species in Varamin, including Sitobion avenae (Fabricius), Schizaphis graminum (Rondani), Metopolophium dirhodum (Walker), Diuraphis noxia (Mordvilko) and Rhopalosiphum padi (L.). Despite of other species, S. avenae preferred feeding on ears instead of leaves. M. dirhodum or S. graminum were dominant species in the different investigation years. However species dominance varied temporally and S. avenae became dominant species in early May of 2000. Population of different wheat aphid species increased exponentially in April, the peaks were observed in late April or early May and then decreased rapidly. Study on the population structure of wheat aphids revealed that adults and winged forms composed a little portion and the majority of aphid populations were belong to nymphs and wingless forms. However aphids had low populations in late spring due to impact of natural enemies and at this time produced only alatae, which were important in terms of distribution, survival and overwintering.

This experiment was conducted in order to evaluate the effect of different plant density and sowing dates on white sugar yield and its componests (Ic variety) at experimental field of Islamic Azad University of Karaj in two years (1999-2000). A split plot layout within a randomized complete block design with four replications was used. Main plots were planting dates (March, 25th-may, 5th-june, 15th), sub plots were plant densities (6,8 and 10 plant m-2). The results showed that reduction in the length of growing season due to delay in planting, reduced the plant ability to spread close its canopy on time, and to use the environmental potential well before the maximum vegetative growth was reached. In addition, autumn low temperatures decreased the rate of sugarbeet growth and consequently smaller roots were produced. Root yield and it componets, at various sowing time and plant density showed that delay in planting significatly decreased root yield, and white sugar yield but increased sugar percent. The most sugar percent and white sugar yield obtained from sowing in june, 15th and May, 5th consequently. Eight plants m-2density produced maximum white sugar yield. Moreover first planting date (March, 25th) produced maximum root yield. So, on the basis of the reuslts obtained, 8 plant m-2 and Sowing in May, 5th might be suitable for maximum sugarbeet production. Results showed if the amout of growth degree days and the extent of difference between night and day temperature were higher than 15°C, white sugar yield might be increased.

The aim of this study is to examine the effects of uncontrolled variables such as: temperature and rainfall on the yield selected crops. The required data were obtained from the ministery of agri-jehad and meterology organization. A Cobb-Douglas production function was applied to estimate different parameters and compute. The results indicate that if the temperature increase by 1°c,wheat, potatos, rice, cotton, corn and barely in Lorestan, Fars, Zanjan, Fars, Kermanshah and Khorasan show the most response respectively where as, if the rainfall increase buy 1 mm above mentioned crops show the most response in Khorasan, Fars, Zanjan, Fars, Kermanshah and Khorasan show the most response respectivelly.

In order to investingate the effect of three potato harvesting machine in Ardebile on the cost/yielding rate, field efficiency, needed power to run. Harvest utility and strength of the machine in opinion of the operators, an experiment has been done in the field. In order to determine the field efficiency an experiment has been set with randomized complete block design with three replication in three villages. To determine the cost/yield rate the collecting data from local operators and technicians has been used. Using ASAE formula helped us to calculate this factor., In order to calculate the needed power to run each machine. draft total power and linear velocity have been measured, To evaluate the utility and strength of the machines two 2 questionnaires have been prepared and been answered by operators. According to the results of the field efficiency. There was significant difference between treatments. Based on these results the American design with 0.33 ha/hr has the best field efficiency and then Sabzdasht Isfahan and Russian design. Based on the other results, there was significant difference between treatments. It shows that the American design has the lowest value of cost/yield of 48.6 rial/ton and 26.36 hp needs to run, while the Sabzdasht Isfehan has the cost/yield of 6810 rial/ton and 30 hp needs to run. As well as Russian design with 7856rial/ton with hp 40.8 hp needs to run. In the view of operators the American design has the best utility.

Green and Ampt infiltration equation solution is presented by constructing a decomposition series. Simple expressions for the cumulative infiltration depth and the infiltration rate are proposed. These expressions are valid for deep homogeneous soils under ponding condition resulting from intense rainfall events. The solution was compared with the exact implicit solution and with the Lambert-W solution of the Green and Ampt equation. It was found that with three terms in the series, the decomposition solution has maximum error of about 0.15%. The inclusion of additional terms in the series reduces the error. With four terms, the decomposition series yield an error of about 0.02%. The accurate of three-term decomposition solution seems adequate for most practical calculations. Futhure more, its simplicity of implemenation makes it suitable for fast hand calculations.

The soil retention curve is needed for modeling water movement and solute transport in the vadose zone. The soil calcium carbonate (CaC03) is a constituent that affects the retention curve via its absorption energy, which differs widely from the other soil materials. The objective of this study was to investigate the effect of calcium carbonate on the retention curve dynamics. Consequently, 32 soil samples with different calcium carbonate contents were selected. The soil samples were delivered to the laboratory to determine the particle size distribution, equivalent calcium carbonate and water retentions at 0, 10, 33, 100,300,500 and 1500 kPa. The soil calcium carbonate was then removed, 0using diluted HCl. The particle size distributions and the water contents at 300, 500 and 1500 kPa were again obtained with the pressure plate apparatus. The soil cumulative curves and water retention curves with and without calcium carbonate were compared. The results indicated that the precipitation of calcium carbonate did not affect the retention curve through reducing the pore radii. The results were also indicated a significant increase (p=0.001) in the water holding ability of the soil after removing the calcium carbonate. This can be related to the lower absorption energy of the calcium carbonate in the soil.  

One of the high-consumed domestic species in the production of different products is fagus orientalis, while drying its thick lumbers (as an important stage of the process) is somehow difficult. In our country, compartment kilns--package loaded and track kilns-- are used for timber drying. However, from different viewpoints such as uniformity of air velocity between timbers, lumbers stacking and loading, construction expenditure, etc. each of the kilns has advantages and disadvantages concerning its basic engineering design. Some factors such as air velocity and sticker thickness contribute to the uniformity of final moisture content in the kiln package and therefore the possibility of occurring different defects. These factors affect the air travel distance before re-heating, which is not the same in the two types of the kilns. In the present research, the possibility of reaching saturation in the air traveling between lumber stack was investigated through a mathematical model according to the lumbers and stickers thickness, wet and dry bulbs temperatures, air velocity, wood specific gravity, and lumber moisture loss per day. The outcome of the model verified through the results of experimental observations. In general, the results of this model indicate that for the drying of 7.5 cm fagus orientalis lumbers, usage of 2.5 cm stickers in a track kiln with the air velocity of 1.5-2.5 m/s and application of T4-T2 schedule leads to the most appropriate results concerning the quality of dried lumbers. In case of using a package loaded kiln with 2.5 m/s air velocity, maximum allowable package width for optimum drying is about 4.8 m, and with 1.5 m/s air velocity, maximum package width would limited to 3 meters.

The main purpose of this study was to assess the adaptability of extension programs with educational needs of rural women in city of Qhazvin. This was a descriptive and correlational research and a questionnaire was developed to collect the data. Population for this study included all of the 167 women who have participated in extension training programs during 1998- 1999 in the city of Qhazvin. From 167 questionnaires finally 153 was returned. After collecting the data and processing with using SPSS win package this results were obtained. From proposed question four of them indicated to have positive relationship with respect to the independent variable of educational needs:1) the number of contact with extension agents,2) using radio programs,3) literacy rate, and4) family income from farming.This study had three major findings. First, it is important to design programs with educational based on rural women needs. Second, evaluation of extension training coureses can bean appropriate factor to increase the effectiveness of rural women. Third, it was found that radio was the least expensive mass media to convey messages to a large number of people, so it is important to provide radio programs based on needs of women farmers.

Some physical properties including coefficient of static friction, angle of repose and terminal velocity of two common types of garlic cloves (white and pink) in Iran were measured at the moisture range from 34.9 to 56.7% on wet bases. Analysis variance (ANOVA) showed that, coefficient of friction, angle of repose and terminal velocity for both types of garlic cloves were affected significantly by moisture content (P<0.01). Relationships between the physical properties and moisture content were expressed by appropriate equations and evaluated by using analysis of variance (ANOVA). Comparison of means were performed using Duncan's method. The coefficients of friction of two types of garlic did not show any significance difference at 5% significance level. The mean values of angle of repose for both type cloves were significantly different, but empty and filling methods were not significantly different. The terminal velocity of three mass fractions (small, medium and large) for both types of garlic were determined and values had significantly different. The maximum and minimum coefficient of friction was 0.74 and 0.26 against steel galvanized and rubber respectively. The values of angle of repose were between 36.1 and 43.5 degrees, as well as maximum and minimum values for terminal velocity were 16.66 and 9.82 meter per minutes respectively.

Essential oil of Ziziphora clinopodiodes Lam. was extracted by steam distillation and its antimicrobial effects on Escherichia coli, Staphylococcus aureus, Pseudomonas aeroginosa, Klebsiella pneumonia, Bacillus subtilis, Bacillus licheniformis, Streptococcus faecalis, Candida albi cans and Saccharomyces cerevisiae were studied. Disc diffusion method was conducted to evaluate the zone of microbial growth inhibition at various concentrations of the essential oils. The antimicrobial effect was aslo studied against microbial suspensions to find out MIC (Minimal Inhibitory Concentration) and MBC (Minimal Bactericidal Concentration). The essential oil from Ziziphora clinopodiodes Lam. was found to have remarkable antimicrobial property against all the microorganisms except P.aeroginosa, The oil exhibited its best antimicrobial activity within a maximum of 45 minutes. 17 components were identified identified by Gas Chromatography and Mass Spectrometry (GC and GCIMS) analysis of the oil, out of which pulegone (24.5%), Neomenthol (12.8%), Cyclohexene, 5-methyl-3- (1-methenyl). trans (12.2%), 2,4-cycloheptadien - 1-one, 3,6,6-trimethyl (0.2%), Piperitone (4.2%), and Limonene + 1,8 cineole (4.1%) constitute major parts of the oil. Monoterpenes seem to have antimicrobial role. It seems necessary to explore antimicrobial properties of new harmless antimicrobial agents from natural sources as substitutes for common chemical drugs.