Year:2005 | Volume:11 | Issue:2|Papers Count:22

This study explores productivity potentials in the shrimp farming in Bosheher province as one of the major shrimp producing region in Iran, using the Tornqvist-Theil index of total factor productivity (TFP). In addition, some partial factor productivity indices including labor, capital, and intermediate input productivity indices were computed. The indices were derived based on the data collected from 32 out of 103 active shrimp farms in 1381 in Bosheher. Results indicate that TFP index varies from 0.35 to 1.48 units among the producing farms in the sample. 64 percent of the farms in the sample indicate productivity less than the average farm productivity, while the rest reveal a TFP above the average farm total factor productivity. Furthermore, considerable differences in intermediate input productivity as well as labor and capital productivities are revealed among the farms in the study region. The presence of highly productive farms in the sample and the vast difference in the partial as well as total factor productivities among the shrimp farms in the region reveal the fact that there is a good potential for enhancing productivity and consequently reducing the unit cost of production in the shrimp farming in the study region.

The important difference of livestock farms with other sectors is the level of risk and uncertainty existence in this sector. In the first part of investigation, the degree of risk in poultry Industry is empirically estimated using the safety-first rule. The result shows that the majority of poultries are facing with a high degree of risk aversion. The last part of investigation discusses the relation between the degree of risk aversion and economic-social properties of poultries (e.g. age, experiment, literacy, insurance and production period, etc…). Empirical results demonstrate that only literacy and production period has significant effect on degree of risk aversion of poultries. Where as the other factors has not significant effect on degree of risk aversion of producers.

This study is going to determine reciprocal relationship between agricultural growth and income distribution in rural areas by using linear and non-linear Ahluwalia and growth models. Study the rural areas independently and review the agriculture role are the advantages of the work. This research is a library and documentary based study and has used some economic soft wares particularly Eviews along with time series of 1971-2001 for the estimations. The result, showed that: rural income distribution has not been affected by the economic growth in agriculture sector; The Kuznets' hypothesis of income distribution in rural areas is not accepted in this context. The index of income distribution inequity in rural areas has a direct relationship with agricultural economic growth rate. Investment in agriculture sector has not had any meaningful effect on the growth of agriculture. Labor growth rate in agriculture sector, has had indirect relationship with agricultural economic growth rate, and finally, the agricultural economic growth rate, within the time being examined, has not been in favor of the poor (pro-poor).

Root rot and crown rot of rice is one of the important rice diseases in Gilan and Zanjan provinces. During 1999 - 2002 different regions of rice grown in two provinces were surveyed. Infected plants and soils around the roots have been collected from studied areas. Roots and crowns of infected plants were cultured on PDA, PPA and CLA media after surface sterilization with 05% sodium hypochlorite. Collected soils suspensions were provided in water agar liquid to isolate casual agent from soils around the roots. The casual agent of disease was recognized as Fusarium moniliforme which isolated from crown and root of infected plants and soils. The color of colonies on PDA medium initially was white and then became violet to grey. Microconidia were chain and macroconidia were cylindrical and long with 3-5 septa. The disease was severing in some areas especially in Zanjan province around the Ghezel Oezan River which had shown 70% to 80% infection in some places. There was not any rotation between rice cultivation in this area and just conventional types such as Champa or Gerdeh have been cultured. Eight new cultivars of rice were cultured in natural infected farm to select relatively resistant to disease. However Binam was the best cultivar had shown resistance to disease and yield production. Most area in Zanjan province were used sowing seeds rather than using seedling which infected plants can be eliminated.

Evaluation based on the content assessment, input assessment, method assessment, and output assessment is a main principal of education and learning process. That in its nature lead to the success and sustainability of educational system for access to its goals. The main goal of present research is identifying agricultural technical and vocational trainers cognition ratio of evaluation process and verifying their attitudes. following the verifying of influencing variable on type selection of used tests for evaluation of students learning. all of statistical population of this research are agricultural technical and vocational trainer that 100 person selected as sample by simple random sampling method. As far as classification of research by objective is concerned ,this study follows a correlation research methodology. Since it was not possible to control the concerned variables. a quasi - excremental research method has been employed. Also, an export facto research type has been used in terms of the time concerned for collecting data needed for theoretical section and information, a variety of methods have been adopted: documentary study, literature review, search in internet and data banks. Also, direct interviews and observations have been used for gathering field information or data. SPSS11 software and the latest available version of Multinet were used to process the collected data. In hypotheses testing, totally 10 hypotheses proved to be true. In order to finf out to what extent the dependent variable(rate of using varied evaluation methods) was influenced by the researchsl2independent variables, a backward multivariable regression analysis was employed. Finally, some variables, inc1udeingcognition rate of performance tests (with the highest rate of positive impact), easiness rate of design and scaling tests, length of teaching ,students level education text difficultness degree, with respectively the highest rate of impact on the dependent variable entered the equation to explain for greater than 66% of changes in the dependent variable.

In this research, the sorkhe-hesar forest park in the east of Tehran was chosen. According to the application of Land-use planning principles and with the use of GIS, finding the suitable places for afforestation and green area development was done in this region. After the basic studies and providing the region thematic maps, digitizing, analysing, adding up and themes overlaying were done in GIS environment. In the end, the region ecological map unit way produced, on the other hand, the afforestation and green area development ecologic model was suggested in five classes for the region after testing and evaluating of Makhdom Forestiry Model.Finally, with regard to the common specification of semi-arid zones and also the ecologic characteristics of species which can survive in such zones, the introduction of suitable species for afforesting in the classes one to three was done with regard to the suggested model of the region capability classification for afforestation and green area development. Classed four and five were emitted because these classes do not have suitable conditions for establishing a successful afforestation in future.

During 1999-2001 studies were carried out to collect and identify bugs of the family Anthocoridae in Shiraz region (Fars province). A total of 11 species were recorded from t his region.They are listed as follows:1.Temnostethus sp. 2.Anthocoris gallarumulmi (De Geer) 3.Anthocoris pilosus (Jakovlev) 4.Orius (Orius) niger Wolff spp. aegyptiacus Wagner 5.Orius (O.) laevigatus (Fiber) 6.Orius (O.) pallidicornis (Reuter) 7.Orius (Heterorius) horvathi (Reuter) 8.Orius (H.) vicinus (Ribaut) 9.Orius (H.) laticollis (Reuter) 10.Orius (H.) perpunctatus (Reuter) 11.Orius (Dimorphella) albidipennis (Reuter) Two species of Orius albidipennis and Orius niger were found to be important flower bugs as biocontrol agents in the region. Information about collection data for each species were also presented.

Study on bioregional characteristics of bollworm Helicoverpa armigera (Hub). in the cotton fields of Golestan province was carried out during 1997 - 1999.This pest produced five generations per year and the last four generations were active on cotton. The adults were active at night. They usually laid their eggs singly on buds, apical leaf, flower bracts and boils of cotton. The newly emerged larvae were appeared after 3 - 5 days. The larval period lasts for 16 - 17.5 days with four ecdysis per five larval instars. Duration of pupae is 11 -14 day. Pupation occurs under ground in an earthen cocoon. Over wintering takes place in pupal stage as obligatory diapauses and quiescence. Pupal period for heavy specimens (0.38 to 0.44 gr) varies from 150 - 189 , and for light weighted specimens (0.22 to 0.38 gr) from 135- 162 days. The first adults were caught between 29 March to 9 April in pheromone traps. Pest activity begun from late June to early July in the cotton fields. Generation period lasted33 to 35 days. The number of eggs on cotton were789.58 in 17.6 days with mean of 44.9 per days. It seems that the high temperature (38 to 45 oc ) is an important factor decreasing number of eggs and early instars larval mortalities (98 - 100 %) on late June and early July in the cotton fields. The major natural enemies were six species which were identified as parasitoid wasp on eggs, larvae and pupae as follows: 1- Trichogramma brassicae (Bezd.) 2- T. embryophgum (Har.) 3- Habrobracon hebetor (Say.) 4- Barylypa amabilis (Tosg.) 5- B. pallida (Grav.) and 6- Ichneumon sarcitorius ( L.)

With attention to rate of growth of population in Iran, it is necessary to produce more food. Also for limitation of water resource of country, one method of developing of irrigated fanning is: "Rain Water and Harvesting Systems" in arid and semiarid zones. In this research, some of climatical and soil properties and water requirement of recommended Crop (SC704 forage corn) was investigated. For this aim 24 plots prepared at Lashgarak Latian watershed in north of Tehran. Data was measured in watering year Qct 2001- Sep 2002 are: daily rain, runoff, evaporation from class A pan. The plots were 30 to 100 m2, This research was conducted with 3 treatments of rate of catchments to basin areas, as 1:1, 2:1 and 3:l.Respectively. The results of forage maize (SC704 variety) Yield showed that this system can supply 50 to 70 present of needed water for an economical crop. Also, supplementary irrigation water was 10 to 20 percent of actual evapotranspiration of forage maize. Yield efficiency of forage corn in the treatment with 3:1 runoff to basin area was 70% of control Yield, equal 28.8 tons/ha. The yield of other treatments (2:1 and 1:1) Were 22.8 and 9.6 tons/ ha. The important point in this system is reserving a part of rainwater harvested in separate place for supplementary irrigation of crop in summer, that in this research was 62 mm or 62 lit/ m2.Althogh amount of runoff collected was 55 to 105 lit/m2 in different plots.

Among horticultural crops of our country, cherry with 12 percentage of total world yields has allocated special rank. One of the problems which cause to unprofitablity of cherry orchards is fruit cracking. This phenomenon happen duo to direct water absorption. rate of water absorption is related to fruit properties and characteristics. Fruit characteristics such as fruit size, firmness of fruit texture, total soluble solids, cuticular properties are effected on this disorder. The Larger fruits are more susceptible to cracking, also fruits with more firmness texture duoto Low capacity for expansion lead to early cracking. In order to evaluation quantitive and qualitive characteristics of 6 iranian and foreign cherry cultivars and relation ship of this characterisitcs with cracking percenty. This research was carried out on the basis of complete randomized design (CRD) in khamalabad collection orchard. The cultivars studied include to takdaneh, shabestar, siah Mashhad, Bing Lambert and Napoleon. The characteristics Evaluated including rate of cracking, weight, Length, diameter, textur firmness, total soluble solids(TSS), volume and calcium content of fruit. On the basis of results of this investigation the most TSS rate were belonged to Bing, Takdaneh and shabestar cultivars and there was direct relationship between rate of TSS and cracking. The most firmness of fruit texture was belonged to Bing and Takdaneh cultivars. There was no distinct relationship between rate of calcium and fruit cracking.

In order to evaluation of growth reaction yield and yield components of cotton under effect of distance between first and second irrigation an experiment was conducted as factorial based on completely randomized block design with4 replications in Birjand at 2002. In this study treatments including cotton Birjand race and Varamin variety and 5 distance between first and second (1,2,3,4,5 week) were investigated. The results show that seed index, lint index, boll number per m2, seed number per m2, boll size and fruiting coefficient were high in Varamin variety. Varieties were not significantly different for traits as eash yield, lint percentage, seed numbers of boll, lint yield, seed yield. Also distance between first and second irrigation was significantly different for seed number of boll and seed yield as greatest seed number of boll in distance of tree weeks irrigation and least seed number of boll in distance of five weeks irrigation were observed. Also the highest seed yield was in distance of one week irrigation compared to two, tree, four weeks and least seed yield was in distance of five weeks. Traits such as yield, lint percentage, seed index, lint yield, lint index, boll number per m2, seed number per m2, boll size and fruiting coefficient were not affected with first and second irrigation distance. Therefore we can increase first and second irrigation interval until 5 week without decrease in cotton yield.

In a green house experiment, the affects of Saline water (0 and 8 gr Lit-1NaCl) on the grain and biological yield, potassium concentration, and leaf Potential were analyzed in 30wheat cultivar. This analysis was done in a factorial experiment based on Random Complete Block Design in 3 replications. In the controlled treatment irrigation with ordinary water and in the salty treatment irrigation with NaCl was done. Gradually so that amount of salinity would stay at 15dsm-1. Based on its results the salinity in all of the cultivars decreased grain yield and biological yield. In stress situation the amount of seed yield and biological yield decreased respectively by 53.5% and 63.6%. In all of the cultivars, Arvand- 1 and Karchia-66 had a significantly higher grain yield compare to the rest. Atrak, Pitic and Bolni had the least grain yield stressed situations. In the flowering stage tolerant cultivars like Karchia-66and Chamran had a high K+ Concentration. Due to. The results the increase in the Na+ concentration in sensitive cultivars is more intensive that tolerant ones. In this experiment it is seen that Ghods, Atrak and pitic cultivars had the least K+/Na+ ratio. The cultivars, which had the least K+/Na+ ratio, had the highest Na+ concentration during stress and by considering yield and STIy these cultivars are one of the most sensitive to salinity. So it seems that the increased accumulation of Na+ compared to K+ in the leaves and the hazardous effects of this ion is the real reason for yield decrease. Based on the results of this experiment, there is a significant positive correlation between he leaf water potential and its yield So much so that in cultivars with higher leaf water potential in salinity stress there is higher resistance to salinity. This fact showed that avoiding salinity is the main reason for the resistance of salinity in wheat and the tolerance mechanism could have a less reason.

In order to investigate the effects of drought stress on yield and some agronomic and physioloyical characteristic in rapeseed (Brasica napus L.) cultivars a field experiment was conducted as split-plot arranged in a Randomized Compelete Block Design with four replications in 2002/3 of karaj-Iran (at:35°,59'Northen and 50°,75 estern). There were two factors, Irrigation at two levels (80 percent of evaporation as control and drought stress from stem elongation stage) as main plots and cultivars in 10 levels: Sarigol, Goliath, Heros, Comet, Arnica, Sw5001, Crackerjack, Eagle, Wildcat, Swhotshot as sub factor. The factors under study were: Biological yield, Grain yield, Harvest index, 1000Grain yield, Oil percent, Number of lateral branches, Number of pod in main branch Number of pod, Pod lengh and Praline percent. Results showed that no significant difference on Biological yield, Grain yield, Harvest Index,1000 grain weight and Oil percent between Cultivars, Irrigation levels and interaction effects. Eagle C.V. had maximum praline percent(0.23%)at 1% level. Interaction effect of irrigation levels and cultivars showed that, on drought stress, maximum pod length (6.7cm) and number of lateral branches/plant (6.2) belonged to Arnica at 1% level. Maximum praline percent belonged to Heros and Eagle C.V. (0.422%) at 1% level on drought stress. Heros and Comet cultivars had maximum grain yield with 3830 and 3620 kg/ha respectively on drought stress compared to other cultivars that may had a better adaptation to the drought stress.

In order to study the effects of different rates of sulfur coated urea and other nitrogen fertilizer sources on seed yield and quality of winter rapeseed (SLM046 Variaty) an experiment was conducted in Zanjan Agricultural Research Center during year 2001. The experiment was carried out in three replications using a factorial experiment with a randomized complete block design .Five rates of N(0,60,120,180 and 240 kg/ha) from four different sources (sulfur coated urea (s1),urea (s2) ,ammonium nitrat (s3) and ammonium sulphate(s4) )were used in this experiment . The results obtained from analysis of variance showed that rate and sources of nitrogen had significant effects on seed yield (p<5%<p<1% respectively). Interaction effects of nitrogen rates and sources on seed yield was not significant. The highest seed yield (4216kg/ ha) was obtained from the application of 240 kg/ha N and the least yield (2408kg/ha) was obtaind from control(without nitrogen fertilizer) treatment. The results showed that the best source of nitrogen is Urea and the best rate of nitrogen is 240kg N. Highest yield was obtained from S 2 N 240 treatment. The highest oil yield was also obtained with highest rate of nitrogen, showing that rapeseed has high nitrogen requirement .there was a positive and significant correlation between seed yield and plant characteristics such as leaf nitrogen content<pod number, grain protein content, biomass production, plant height, leaf number and grain number per pod. There was a great correlation between oil yield and grain yield (r=0/99**). According to this results, selection of Nitrogen fertilizer sources and rates of nitrogen must be selected according to yield potential of canola cultivars.

In a completely randomized design, 24 Holstein male calves (275 kg initial BW) were used for evaluating the effects of Clinoptilolite on rumen ammonia nitrogen, plasma urea nitrogen, feedlot performance and carcass characteristics of Holstein calves. Animals were assigned randomly to one of three dietary treatments for 110 days as follows: group 1; %0urea and 0% Clinoptilolite, group 2; %2 urea without Clinoptilolite, group 3; %2 urea with %4 Clinoptilolite. Average daily gain and feed conversion ration was differ (P<0.05), but differences for feed intake were not significant. Means for average daily gain were 1.3, 1.21 and 1.26 kg/day, for feed intake were 7.64, 7.59 and 7.68 kg/day, for feed conversion ratio were 5.81, 6.04 and 5.93, respectively. Plasma urea nitrogen and rumen ammonia nitrogen were influenced by diets (P<0.05), with the highest means in group 2 and lowest one in group 1. Hot carcass weight and eye muscle diameter were changed among treatments (P<0.05). Abdominal fat weight and fat diameter on eye muscle were high in control group and low in group 2. Group 3 was between another two groups in all parameters. Treatments affected (P<0.05) the protein and fat percentage of 9-10-11 ribs, with the highest protein percentage in group 2 and the lowest in control group. In conclusion, addition of Clinoptilolite to diet containing urea not only decrease ruminal ammonia nitrogen and plasma urea nitrogen concentrations, but also had partial positive effect on feedlot performance and carcass characteristics of Holstein calves.

In this study, three geographical sites in north of Iran with the elevations of 40, 500 and 1000m were selected. In each site 10 trees, totally 30 trees were randomly marked and felled. From each tree, three 5 cm thick discs at the heights of 1.30,3.00 and 6.00m were cut and the tree trunk was converted into three logs and was carried to the sawmill. Physical and mechanical properties including specific gravity; static bending (MOE and MOR), compression parallel to grain, compression perpendicular to grain, shear parallel to grain, tension perpendicular to grain (maximum stress), cleavage resistance, hardness (tangential, radial and cross section), impact resistance, were performed according to ASTM standards. Physical and mechanical tests results indicated that at the elevation of 1000m all mechanical properties except that static bending and compression parallel to grain increase with the Increased in density, while at the elevation of 40m they all dealing. The differences between the three sites were significant at 1% significant level. At 500m altitude all of the wood mechanical parameters were good but at in 40m due to the reduction of specific gravity, strength of wood decreased and application of wood was limited.

In this research the correlation between annual temperature and precipitation with radial growth of Pinus eldarica in three parks of Tehran, Chitgar, Almahdi and Sorkhehesar using data gathered from each nearby metrological stations were evaluated. After cross dating and measuring ring widths, long-term variations were removed by standardization. The tree rings of three sites have shown somewhat different responses to climate. The correlations between indices and annual precipitation demonstrated that precipitation of prior October in Almahdi and Chitgar Park and precipitation of March and April in Sorkhehesar Park and precipitation of August approximately in all sites have most positive influence on ring width of Pine (Pinus eldarica) trees. Lack of significant correlation between radial growth and temperature indicates that trees in drought area are more influenced by precipitation

This research was performed to study the properties of pulp and paper prepared from bagasse. Depithed bagasse (Wet method) was prepared from Pars pulp and paper mill, Khozestan province. The cooks was done for 30 and 40 minutes by neutral sulfite semi chemical process using the cooking liquor of Mazandaran pulp and paper mill having 10% and 20% chemicals on the basis of dry bagasse weight. Then, the pulps were refined up to 410±25 CSF by using PFI Mill refiner. Then, hand sheet 127 gr/m2 were made from different samples of pulps and the strength properties of hand sheet were measured. For study the resistant properties of hand sheet papers, used the TAPPI standard. The studies shows that with increasing chemicals and cooking time, the yield decreased, but the resistance indexes of paper such as Ring crush Test (RCT), Stiffness, Tensile Strength, Burst Strength, Breaking Length was increased. The exception was tear Strength that decreased due to increased refining.

At first, the used milk fat depending on type of yogurt was standardized (2.5% fat for ordinary fruit yogurt and 0.1% for low-calorie fruit yogurt), the intended additives (i.e. powder milk, stabilizers and sugar), were added in the amounts needed, then homogenization, pasteurization and incubation process were performed until the yogurt was formed. Thereafter, the fruit was added and product was packed. After production two types of yogurts, complementary tests of coli form, mould and yeast, determination of fat content, acidity, lactose content, solid not fat content, calorie content, viscosity, pH and panel taste (texture, color, flavor and taste) were performed. The effects of time (3, 7 and 15 days), kind of fruit (black cherry, peach and strawberry), stabilizers (pectin and gelatin), temperature (4 and 25 C), additionally, for low calorie fruit yogurt, sugar (3 and 5%) were studied. Based on this result the best formulation was proposed (for ordinary fruit yogurt: gelatin 0.4%, pectin 0.3%, milk with 2.5% fat 82-85% and jam of fruit 14-17%; for low-calorie fruit yogurt: gelatin 0.4%, pectin 0.3%, milk with 0.1% fat 80%, puree of fruit 14-17% and 5% sugar 14-17%).  

The paddy plant is subjected to natural loadings throughout the growing season and severe mechanical treatments during harvesting. In order to aid in the engineering design of the harvesting machines, there is a need for more information concerning the physical and cutting properties of paddy stems. In this study, physical characteristics such as, moisture content, cross-sectional area and linear density of stems as well as their effects were investigated on the cutting force of paddy stem. A shear apparatus with reciprocating mechanism was designed to measure the cutting force. A factorial experiment in the form of Randomized Complete Design was used to determine the effects of variety, blade velocity, blade bevel angle and blade type on the shearing strength of paddy stem. Analysis of variance of the data indicated that variety; cross-sectional area and moisture content as well as interaction between variety and cross-sectional area at 1% level, also, variety and moisture content at 5% level of confidence were significant. The cutting force increased with an increase in cross-sectional area and decreased with increase of moisture content. Based on the statistical analysis results, variety, shear velocity and blade bevel angle affected the shear strength at 1% level but blade type did not. Also, the interaction between variety and shearing velocity was significant. The results of Duncan test showed that the maximum and minimum shear strength were related to the variety of "Khazar" and "Hashemi" with average of 204.1 and 180.9 Kpa, respectively. Also, the shear strength for shearing velocities of 0.6 and 1.5 m/s were 204.1 and 180.9 Kpa, respectively. The difference between blade bevel angle of 35 degree with 25 and 30 degrees was significant. Interaction between variety and shearing velocity had significant difference on shear strength. The maximum and minimum shear strength was related to "Fajr" with mean of 234.4 Kpa at 0.6 m/s, and "Hashemi" with mean of 161.6 Kpa at 1.5 m/s, respectively.