Year:2007 | Volume:13 | Issue:2|Papers Count:23

In this study, using a sample of 300 Iranian pistachio producers, willingness to pay for pistachio insurance was measured directly and indirectly, The results showed that, if farmers' risky beliefs and preferences were the only factors in decision making, the willingness to pay for insurance would be very high. In this case, pistachio producers not only pay fair premium, but also pay loading costs. More investigations showed that, in addition to risky beliefs and preferences, factors such as government policies, off-farm works, financial difficulties, moral hazard and adverse selection are considered in decision making for participation in agricultural insurance. These factors reduce willingness to pay, so that, on average, willingness to pay for pistachio insurance is only 73.27% of fair premium.

Study of shrimp market is necessary for increasing demand shrimp in gross market. Marketing margins are differences between prices at two market levels. In this study data obtained of farmers, processors and retail market in Tehran modeling with Markup model. The results show that farm gate price, wholesale price and transporting cost are effective in total marketing margin shrimp market. In addition, transporting cost and marketing cost are effective in retail marketing margin. The calculating price efficiency on wholesale marketing margin shows that a unit investment has returning about 2.01. Return of unit investment in wholesale market of shrimp equals 0.38.

Sunflower is planted in about 2000 hectares of Isfahan Province areas every year and most of these areas are in the country of Isfahan specially Mahyar area. Sunflower is usually planted as second cropping after end of irrigation or harvesting of cereals, in summer. There are some farmers that they get more than 2.5-3 t/ha yield but sunflower yield is low in some fields and it was caused to decrease of planted areas in recent years. This study conducted during 1378 to 1380 to evaluation limited factors of sunflower yield in this area, Some fields were selected every year and information about their soil, method of planting, Keeping and harvesting were collected. In addition, plant samples were selected at flowering stage from fields every year and some plant parameters were measured as their vegetative growth condition, this information were analyzed descriptively and statistically. Results showed that presentation of honey bee hives in field, head diameter of plants, irrigation times, using of herbicides, number of leaves per plant, planting date and using of land leveler, significantly correlated with sunflower yield and they entered to yield model, respectively. On the whole, R_square was %76 in this model. In the middle of this factors, using of herbicides had negatively and the others had positively related.

A proper understanding of factors affecting water distribution uniformity in sprinkler irrigation is important for developing water conservation strategies. The purpose of this study was to determine uniformity in semi-portable sprinkler irrigation system under different wind speed. The main factors affecting uniformity (i.e. sprinkler spacing and layout and wind speed) with this system were analyzed. The standard ISO 7749/2 has been taken into account to determine uniformity. The type of field test was conducted under single sprinkler condition in south-east region of khouzestan province. The investigations showed that higher CD values are attained with square-shaped spacing. Results also showed that uniformity decreased as wind speed increased under all options of sprinklers layout and spacing. The most suitable sprinkler spacing in order to obtain acceptable uniformity (80%) seems to be to locate sprinklers 25x25m when wind speed are higher than 2m/s.

The Khuzistan plain is one of the most fertile and abundant in surface water resources plains in Iran, in as much as 30% of the total rivers in Iran flow through the region. These rivers create five major watersheds in the region: The Karon watershed, The Marun - Koopal watershed, The Dez watershed, The Karkheh watershed and the Zohreh - Hendijan watershed. Such a vast potential in the region has brought about various studies regarding the development of the region and the building of reservoir dams and hydropower schemes. These studies were basically carried out in watersheds which Laclede any fundamental data for the calculating of the maximum flow during flooding, and there in such water sheds empirical methods were used of calculate such a flow. In this paper in addition to a review of the existing empirical methods and their real kinship with the works carried out to date, due to the preferred use of the Deacon method in the region, a revalue action of the data via this method has been under taken. In order to do so, after a brief survey, twelve hydrometer stations were selected and the data obtained from each completed and rectified. Then by the correlation between area and flood with various flood return periods, results with 98% probability were obtained. The studies also proved that in the Deacon Method the exponential for the equation shows more than 40% error of measurement in the prediction of the Maximum Flood of a flood and thus is not suitable to measure the volume of the inundations Therefore it is suggested that a research method be analyzed to further carry out the study.

Identifying how to use science and technological technique by wheat producers involve a need assessment and study their educational needs in all production levels. This can be enhances their skills and knowledge and to help them to minimize wheat wastes and improved farm management The main purpose of this research was regression analysis need assessment of extension educations for wheat waste decrease management. This is an expos-facto research. Data were collected by questionnaires from 454 farmers who were selected through a stratified random sampling design from 5 region that classified by their climatology (very cold, hot and dry, fairly cold, hot and humid and fairly warm), these region are: Sarab (in Azarbayejan province), Shoshtar (in Khozestan), Torbate-hydarieh (in Khorasan), Gonbad Kavous (in Gorgan) and Marvdasht (in Fars) in Iran. The collected data were analyzed with the multivariable regression analysis. Results from regression analysis indicated that the basic priorities and educational needs are required to decrease wheat waste. In this research all factors related to technical knowledge of the farmers was identified. Regression model showed that lack of technical knowledge in planting, maintenance and harvest explained 4.7%, 11.7% and 3% of variables of wastes. The production waste also was studied in this model. Obtained results indicated lack of technical knowledge explained 7.6% and 12% variations in wheat production waste in planting and maintenance stages. In this model also, prediction of the total wheat waste was studied. The results showed lack of technical knowledge predicted 6% and 6.2% variation in dependent variable in planting, and maintenance stages. Overall results showed, three variables in planting stage, 19 variables in maintenance stages, and two variables in harvesting stage explained wheat wastes.

In order to determine the seeding cycle of beech tree in Kelardasht, Sangdeh and Gorgan forest of Caspian region 96 dominant tree were selected. Quality and quantity measurement on these trees was conducted and then all of these trees were felled down. From each tree one disc was cut above of the ground. These discs were analyzed and measurement such as annual diameter growth rate done on these disc. The results of this study are follow.1-two type of seeding cycle (heavy and light) was detected in beech trees.2- The minimum age of seeding is about 30 years and at this age light seeding usually starts.3- The heavy seeding begins at the age of about 60 to 75 years.4-in single site different seeding cycles observed during the living of trees.5-The light seeding accrues in 1 to 3 years periods but heavy seeding accrues in 3 to 9 years intervals.6-Regeneration of natural forest depends on light seeding cycles.7-This study revealed that natural regeneration must be based on light seeding, therefore forestry practices increases the harvesting cycles from 5 years to 10 or more years in implementation of forestry Project especially in seeding felling in shelter wood cutting systems.

This research was contacted in javaherde that it was plantation with coniferous and broad leaves in 1983 (Aregion with 58 ha and 650 up to 2100 maltitude at western south of Ramsar). The objective of this study was to determine forest floor herbs cover in coniferous and broad leave stand compare with together to assess ecological group. At the first, the flora of this area aggregated and identified and floristically information of this area was analyzed by Anaphyto program with Braun-Blanquet method. 145 plots were studied and main ecological groups and 21 subgroups were recognized in this region covers. We can mention slop direction, soil pH, soil EC, phosphorus, potassium, soil saturation, soil organic matter as effective factors of isolation groups. Comparison of different kinds of deciduous and coniferous and compare them together showed that forest floor herb could separate to five groups contain: Exclusive species. Selective species, preferential species, Accidental species and Amphoteric species. Measuring of light interception rate in any ecological groups showed that coniferous with more canopies has less light interception rate than deciduous. Number of ecological subgroups and exclusive species density, preferential species and species diversity in deciduous was more than coniferous. Height of grassy herbs increased with decreasing of cover canopy percent and adverse.

Wild cherry (Cerasus Avium) is one of the rare and valuable tree species in the forests of northern Iran. Understanding the ecological conditions where this species grows can help us improve the growing conditions for this tree so as to prevent its destruction rather to increase its populations. The objective was to study the distribution of stands of trees or of single tree in the relation to the site properties. to evaluate the ecological stability of stands of wild cherries in the forests of Northern Iran, four regions consisting of a total of 18 plots measuring 0.1 hectare each, were identified in the eastern part of northern forests, namely one site at 740 meters above sea level, another from 1000 to 1350 meters above sea level, two locations in Noshahr / one site 300 meters above sea level (Sarcheshmeh) and the second one from 1000- 1300 meters above sea level (Chenes). Qualitative and quantitative studies were made on the soils and climates of the selected sites. A study of vegetative cover and diameter increments and volume increments and of symbiotic activity of mycorrhize with root of wild cherry showed the trees were distributed from west to east and from low land to uplands, but the stands in midlands (altitude 800-1300 m) were denser. These species were distributed on the northern, north-western, north-eastern, western, eastern, south-western and southern flat slopes. But at the northern section the density of trees was higher and they species were growing lands with 0.8 percent slope. In quantitive terms the studies showed that from the point of frequency density, basal area and volume per hectare: the lowe (1) forest contained 134 trees per hectare, in the studied regions, the number of tree varied from 35 to 134 trees per hectare. Maximum basal area varied from 8.807 m2/h in the lower forest of Gorgan to a minimum of 5.176 m2/h. Maximum diameter was found to the 85cm in the Nowshahr (Sarcheshmeh) location. Maximum and minimum mean heights were 17.6m and 15.06m respectively. Analysis of variance showed differences between quantity parameters such as height, diameter, Crown height, Crown diameter and crotch height. In regeneration studies wild cherry showed that in general the regeneration rate was low because of scatter ring of seeds by birds. The Soil of study site was fertilized on the bases of macro-elements and micro-element. Qualitive studies showed that Noshahr-Sarcheshmeh was the best site and Chenes he worst. Lowe 1 and Lowe2 were placed between the two limits.

This study was conducted to examine the chemical composition and nutrient digestibility of Hamadanian alfalfa forage at different growth stages on Sanjabi sheep and Merghoze goat. Cultivars characteristics of alfalfa including, bush height, bush dry matter and their ratio were measured in four stages of growth (1- Budding time 2- Completed budding time 3-Early flowering time 4-Completed flowering time). Chemical compositions of samples after harvesting from each stages of maturity were measured by proximate analysis methods described by Weende. Nutrient digestibility coefficients of alfalfa were obtained by using four Sanjabi rams (42±2.1) and four Merghoze bucks (34±2.3) during spring in Kermanshah Province. Complete Random Design was used to compare data related to agronomic traits and chemical composition of alfalfa hay, Data related to digestibility were analyzed using Complete Random Design (switch back). The mean was compared using Duncan methods The mean of bush height, amount of dry matter and percentages of dry mater of fifty bushes in the budding time were 42±3.9 cm, 27±4.8g and 17.66±2.3 % respectively, whereas these parameters were 53,6±5.6 cm, 41.8±9.5 g and 23.1±2.6 % for completed flowering time, Crude protein at budding time compared with completed flowering time (21±1.6 vs. 16±1.9 %), which is in contrast with fiber percentages (21±1.1 vs, 24±0.9%). Digestibility of dry matter (OM), crud protein (CP) and crud fiber (CF) at budding time were 63.5±2.1, 74.7±2.8 and 46.1±4.8 percent in sheep whereas these coefficients were 66.7±2.6, 76.4±3.1 and 48.1±4.1 percent in goat respectively. There was no significant difference on DM and CF digestibility at different stages. There were no significant differences between sheep and goat on digestibility except at complete flowering stage, which dry matter and crud protein digestibility were higher(p<0.5) in goat than those in sheep. It can be concluded that despite lower crop yield at budding stage, forage quality and nutrient digestibility was higher (p<0.5) than that at complete flowering stage.

In order to study the effects of heat stress after anthesis on source limitation of six wheat (Stork, Showa, Green, Star, Chamran and Fong) and two barley (Jonob and Sarasary 6) cultivars, two field experiments were conducted in delayed and optimum sowing dates. Plants in delayed sowing date experienced heat stress in after anthesis growth stage. Study of grain yield indicated that the highest grain yield was in Jonob in both conditions. Source limitation difference in experiments, cultivars in experiments and interaction between cultivars and experiments was significant in 1% probability level. Mean of source limitation in optimum and heat stress conditions was 12.5% and 25.5% respectively. Higher source limitation in late maturity cultivars such as Green and Star was related to delay in anthesis and contact of grain growth period with heat stress. In early mature cultivars such as Fong with early anthesis, grain growth period was before heat conditions, while source limitation and also grain yield and grain weight reduction was the lowest in Fong cultivar.

In order to study of relationship between light extinction coefficients (k) and grain yield of sunflower varieties, an experiment was carried out in split plot based on RCBD with 4 replications in educational -research field of Islamic Azad University of karaj in Mahdasht region at 2003. The sunflower varieties in a 3 levels as major factor were Doursephid, Ghalami and Pestei and plant densities in a 8 levels as minor factor were fixed on 50, 60, 70, 80, 90, 100, 110 and 120 thousands plant / hectare. The results of data's analysis showed, the difference of growth period and light extinction coefficient traits were significant in 5% level between varieties but other traits had significant difference between varieties in I% level and just plant height trait had no significant difference. Also the differences of all studied traits in various plant densities were significant in 1% level. Comparing of the averages with use of molti slopes Duncan method in 5% level was indicated the Doursephid c.v with average grain yield of 4063 kg/ha is most prolific variety in this research. In this experiment the optimum density got 80000 plant / hectare and highest grain yield was conducted in 80000 plant / hectare about Doursephid c.v with 4389 kg/ha. By the way the optimum density caused that light extinction coefficient arrived to 68% in pollination period, and lower and higher densities from optimum density caused the increase and decrease of light extinction coefficient respectively and in each two positions the grain yield was decreased.

Grain quality is dependent on cooked and uncooked grain size and grain wide and also grain shape. As rice grain quality is an endosperm trait, its inheritance can be more complicated because the genetic expression of an endosperm trait in cereal seeds is conditioned not only by the triploid endosperm genotype, but also by the diploid maternal and cytoplasmic genotype and epistasis effects. Molecular marker aided selection technique for grain quality would accelerate breeding progress by increasing selection efficiency. In order to map the QTLs for grain quality in rice and estimate the effect of each QTL in phenotypic variation, 63 advanced backcross lines (BC2F 5) derived from cross between IR64 as recurrent parent and Tarom molaei as donor parent, investigated in International Rice Research Institute (IRRI). The phenotypic traits under study included: Uncooked kernel length (UKL), Uncooked kernel width (UKW), UKL/UKW, Cooked kernel length (CKL), Cooked kernel width (CKW), CKL/CKW, Kernel elongation ratio (KER), Kernel length difference (KLD). We analyzed 235 SSR markers for parental survey by agarose and polyacrylamide gels, through them 114 markers showed polymorphism and assigned for genotyping. Transgressive segregation was observed in all traits. UKL showed significant correlation with UKW, UKL/UKW, CKL/CKW. We identified one QTL for each of traits including KLD, CKW, CKLICKW, two QTLs for CKL and KER, three QTLs for UKL, five QTLs for UKW, and seven QTLs for UKL/UKW.

Water stress and nitrogen rates can effect its yield and yield component in corn and both of these items conflict the yield in corn in order to determine the effect of water stress time and different nitrogen rates on yield and yield component corn ksc 704. This field experiment was conducted using a randomized complete block design in three replications in 2004, growing season in research and education of Islamic Azad University of Firouz Abad, The results showed that the grain yield and yield component such as kernel number per ear and ear kernel weight decreased in effect of water stress and nitrogen rates and the maximum decreasing of yield was referred to water stress and nitrogen lack in grain filling period (T3) also water stress and nitrogen lack can cause decreasing of biological yield. Water stress in maximum rate of nitrogen consumption increased harvest index (HI). The effect of nitrogen rate and water stress level and their interaction on water use efficiency was significant. Water stress treatment in vegetative stage increased water use efficiency. The least of kernel number per ear referred to water stress treatment in vegetative stage T1.

In order to determine genetic relationship of 64 genotypes of Durum wheat (including 6 indigenous and 58 exogenous genotypes) experiment was conducted in the form of Simple Lattice Design during 2002 - 2003. In this study the traits of consideration was as follow: seeding time, heading time, flag leaf area, plant height peduncle length, number of nodes. spike length, internodes length, number of fertile tillers, biomass, number of kernel in spike, 1000 kernel weight, grain yield and harvest index. Results archived from Combined analysis showed a significantly difference (P<0.01) between above mentioned traits which explains genetic variety between genotypes. In order to determine genetic relation between lines, Cluster analysis in Ward method was performed and genotypes in question were divided into 5 groups. Native genotypes in an individual group and all other exogenous genotypes (depending on their genetic similarity and/or differences) in 4 other groups which shows similarity between native lines and also difference between exogenous ones. In some groups, several traits showed desirable traits value more than mean value which could be useful to enhance the value of such traits during hybridization.

To study the competitive effects of redroot pigweed (Amaranthus retroflexus) and lambsquarter (Chenopodium album) on potato, an additive experiment was conducted in the spring of 2004 in split-split plot based on randomized complete block design with 4 replications at the Seed Potato Production Station of RAN in Firouzkooh. Treatments were included 2 weed species in main plots (Amaranthus retrot1exus and Chenopodium album), weed density in sub plots (2,66, 5.32 and 10.64 plants per m") and relative time of weed emergence in sub-sub plots (8 and 4 days prior to potato and the same time with potato emergence). Potato, cultivar Agria, was planted in constant density 53000 plants per hectare by row space of 75 cm. To interpret the competitive effects, the Cousens's regression model was used. The results showed that both species of weeds significantly reduced tuber yield. 2, 4 and 8 lambsquarter per meter of row reduced tuber yield 12.8, 22.3 and 27.2 percent, respectively. These values for redroot pigweed increased to 18, 29.4 and 39.6 percent. Parameters i and a estimated by the model were higher for redroot pigweed. Parameter "i" for three levels of lambsquarter and redroot pigweed emergence time were 10.05, 7.95, 4.48 and 19.44, 13.22, 8.86 respectively. Parameter "a" for lambsquarter was estimated 56.99, 48.7 and 31.16. This parameter for redroot pigweed was 61.92, 52.88 and 48.72. Regarding to these estimation, sooner weed emergence will result more tuber yield. Weeds did not affect mean tuber number per plant significantly. But, mean tuber weight was affect significantly. According to the results of this investigation mean tuber weight is the main factor for potato yield loss.

This research was down with the aim of determining chemical and anatomical properties of bagasse used in Iranian paper industries. Wet method depithed bagasse of Pars Paper Company in Khuzestan province was used in this research. TAPPI standards were used for study of bagasse fiber chemical and anatomical properties. Average length, diameter of cellular cavity and thickness of cellular layer of bagasse fiber were calculated as 1.59mm, 20.96, 9.719 and 5.64 (11) respectively. The slenderness ratio, flexibility ratio and raunkel ratio were of bagasse were calculated as 75.86,46.37,116.02 % In addition measuring chemical properties showed that cellulose proportion was 55.75%, lignins 20.5%, Extractives 3.25%, and ash 1.85 %. Measurement of bagasse properties shows that the dimensional properties of fibers and chemical property of fibers are very suitable for use in paper making industries of the country and is better than hard woods and other Non wood herbals.

In accordance with development of new technologies in wood processing, effect of relative humidity on EMC of wood in high temperatures (above boiling of water) has got attention of wood scientists in recent years. In this research, addition to study the required theoretical aspects, mathematical equation for describing psychometric relation of wood in dry bulb range of 93 to 260 C and wet bulb of 38 to 99 C was gathered, developed and investigated. To do this, subjects related to measurement of dry and wet bulb temperatures, saturation adiabatic temperatures, dew point, relative humidity, steam content and anthalpy of moist air was studied and presented. Finally, relative humidity and EMC of wood related to dry and wet bulb temperatures in above mentioned range was presented. According to good agreement of estimated values with experimental results of other researches, it seems that it is possible to use the outcomes of this research as a basis for further studies.

Presence of metal ions in the texture of chemimechnical papers leads to abortion of light due to reaction with lignin and thus yellowing and aging the paper would accelerate. This research is commissioned in order to determine the brightness variation of chemimechanical papers produced in the wood and paper factories of Mazandaran when treating them with metal ions of medium elements and methods of declining it. Two types of chemimechanical sample papers from the factory Were obtained, bleached and unbleached papers. Samples included of two types. First, the samples were smeared with EDTA in different densities. This process ended in neutralization of existent ions in CMP paper samples. In the second stage treatment, after dehydrating each of the above- mentioned samples that were combined with EDTA we smeared them with solvents including metal ions of medium elements and then put them under the radiance of UV Black Light lamps. One of the objectives of this research was to determine what kind of effect could have different metals on the Aging and Yellowing process. In the final stage, we measured the light specification of samples such as Brightness. The highest spoiling effect on the yellowing process was determined to be Fe2+ ion and the lowest effect was issued by Al3+ ion. For decreasing the effect of each metal ion, increasing the density of EDTA, decreasing the PH of pulps and methods such as methylation methods were suggested.

Isolates of fusarium moniliforme, the causal agent of collar and root rot of rice varied in sensitivity in vitro to antibiotic produced by fluorescent Pseudomonas spp. which shown previously to have potential for biological control of this pathogen. One of isolates tested was insensitive to antibiotic at 1.0 mg/ml. Pseudomonas fluorescens produce antibiotic, effectively suppressed Bakana caused by antibiotic - sensitive isolate of fusarium moniliforme. Antibiotic -producing strains were able to suppress disease. These findings confirm the role of the antibiotics in the biocontrol activity of these fluorescent Pseudomonas spp. The results show further that isolates of fungus insensitive to antibiotic are present in the pathogen population and provide additional justification for the use of mixtures of Pseudomonas spp. that employ different mechanisms of pathogen suppression to manage this disease.