IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2005 | Volume:58 | Issue:1|Papers Count:25

The aim in this research was to initially study and determines the factors affecting mass movement through literature review, then by further investigation find the specific factors that are most effective in mass movement in the study area. A time interval of years 1966 to 2000 was employed. A study of change in factors during this interval, area affected by mass movement, and field surveys to check for accuracy of data were carried out. The resulting tables and statistical results were used in a later phase of investigation.In the latter phase, it was found that traditional statistical tests for structuring a simple model usable for landslide hazard are not applicable due to the fact that the effective factors used are qualitative.Therefore, another method, called systematic hierarchal analysis, was employed, and on the basis of oral as well as descriptive standards, coefficient. Q was obtained for each factor. Then for each factor, new values were obtained through multiplication by the factor coefficient. were added to reach a final value. By classifying this value; the ranges of mass movement hazard were obtained in four different classes in the region.

Soil science studies, base of most natural resources research, are of high expenses due to the large number of profiles needed for evaluation of soil properties. So we need methods through which one can evaluate soil characteristics while, using a low number of profiles. Tow common soil studying methods, geology and geomorphology, were compared in Hassanjoon sub-catchment of Taleghan drainage basin, located in 50° 37' to 50°50' longitude and 36° 7' to 36° 20' latitude with high geological as well as geomorphological variations. Initially a map of geomorphological and geological units was prepared through photogeology and field checks using geomorphologic information system of 1:20000 scale. Then were made 60 profiles from which soil samples were taken for physical as well as chemical analysis in which pH, EC, %OM , % CaC03, %silt , %sand and %clay were determined.Results indicate that geological units are not homogenous so that the profiles located at facies in each lithologic unit are of high significant difference (except for pH). So it is necessary to separate facies in each lithological unit. The profiles made in different slopes in each facies were not of a significant difference, and on the other hand, using a high number of profiles didn't add to the accuracy of the study. So geomorphological method (separating facies in lithologhic units) is a more efficient one than geological meihod for soil studies in natural resources, in climates similar to the one in this study.

The process of flow in a river with regard to the river's characteristics such as the kind of bed, roughness coefficient, longitudinal slope as well as the governing conditions in the watershed (basin) is quite varied and complex. These variations along with complexities reach their highest values when flow occurs along a bend or river meander.A study of this phenomenon as it occurs in nature is very complicated, requiring sophisticated equipment and instruments. In order to limit the variables and at the same time introduce a suitable pattern of a river bend (meander) that represents the effective principle dynamic parameters, a physical model, namely a flume of 180° curvature was constructed as a simulation. The bed and sides of the flume were constructed from plexiglass, allowing a uniform flow to occur at a rate of 50 liters per second, at a width and depth of 60 and 20 cm respectively. Three dimensional (x, y, z) velocity measurements were made at different sections using a micropropeller. In total, nineteen cross sections of 10° intervals were taken for evaluation. A maximum of 49 points of three dimensional velocity measurements were made at each cross section.Results indicate: a maximum of transverse gradient at water surface occurs at 90° curvature while a minimum occurring at 30 and 100 degrees of the bend. A study of in depth three dimensional velocity profiles indicates a maximum flow velocity at a depth of 7.7 cm from bed surface and a minimumata depth of 5.7 cm below water surface.

Derived flood frequency distribution method with geomorphoclimatic instantaneous unit hydrograph, the joint probability density function (pdf) of storm intensity & duration, Philip's equation of the infiltration process were employed to derive a flood frequency distribution in Menderjan catchment (one of the subbasins of Zayanderud watershed). This method provides an alternative to estimate flood frequency distribution in ungauged catchments. This frequency distribution was compared with frequency distribution resulted from statistical method (LP3 distribution). The results in this study indicated that using climatic climax soil parameters was in a better agreement with the observations than the ordinary conditions of soil parameters. This method was of poor performance in estimating high return period floods.

Analysis of low flow is one of the important considerations in any water resource project. Meanwhile, as a general idea it seems that flow control is more important than drought mitigation but it is necessary to pay more attention to drought problem in future projects. In this paper, available data for 12 selected watersheds were analyzed and low flows of 30 day with different return periods were calculated for each set of flow data. Also, hydroclimatic and geomorphologic parameters were considered to obtain the most effective factors on low flows which help to separate homogeneity area. The most effective factors were: area, mean annual precipitation, average weighted infiltration and average slope of the watershed which illustrate 99.36 percent of variation of data. Then homogeneity areas were identified using cluster analysis.Meanwhile, regression and low flow indication were obtained using the data. Results were compared with data of 4 control watersheds to evaluate accuracy of the model which showed more efficiency of multivariate regression method as compared to low flow index method in different return periods.

Iran is one of the countries located in the desert belt of the world with this always having caused major problems. Beside the adherent susceptibility of Iran for desertification, maltreatment of natural resources has added to the intensification of this process. One of the most significant factors to be tackled is the agriculture issue. Therefore, it is essential to do more research on agricultural lands in different parts of the country especially in semiarid regions where the desert extension along with agricultural land deterioration is more pronounced. Research must be done to determine whether the region is suitable far agriculture or not, and if suitable what kind of agriculture should prevalently be prevalently applied so as not to face problems in either production or land utilization, also, to prevent land deterioration in the region. To achieve this, a region in Khodabandeh (Ghydar), Zanjan province was chosen for study. Based upon previous soil studies, some blocks of land were specified and then different kinds of agriculture on these blocks were compared in a completely randomized block scheme. Different maps of the region were produced using geographical information system (GIS). Yields in agricultural products were evaluated. Soil sampling in each part of the agricultural land was done. Soil factors in a depth of 0-30 centimeter were evaluated. Two classes of information, namely soil - improvement factors of nitrogen, phosphorus, potassium, humus, lime as well as soil- deterioration indicating factors including pH, EC, SAR were measured. The study of factors in a Completely Randomized Block Scheme showed that there were significant differences among treatments (agricultural lands). A comparison of treatment means, using Duncan Mean Comparison indicated dry land farming on sloping land as the most unsuitable treatment and the treatment of multi cultivation irrigated land as the most suitable one.

One of the most important factors in developing forests is Production of seedlings Free of Pests and diseases to be transplanted in the forest. Among softwood and hardwood trees, Aeer velutinum is the most useful species because of its easy planting, rapid growth and good wood quality. Pests and diseases are important factors affecting plant growth and development in the nurseries. Nematodes constitute one group of these agents that have not so far been studied in forest nurseries in Iran. In a survey of maple seedlings in the forest nurseries with student growth, chlorosis and weakness, Pratylenehus vulnus, Fusarium solani and F oxysporum were isolated. The interaction of these fungi and the nematode were studied in randomized complete block design with four a replications and six treatments. In treatment with F oxysporum the average height of seedlings were 28 & 30 after 4 & 7 months; in treatment with F solani, the averages were 27 & 25.75 cm, and in control they were 28.5 & 30.5 cm, respectively. The seedlings were not truly infected with these two fungi. But in treatment with nematode alone 75% of the seedlings died. In the treatments with nematode and fungi combined, the population of nematodes decreased and the growth of the seedlings increased (in comparison with nematode alone), F. oxysporum showed a more antagonistic effect than F solani on the nematode. Therefore, the nematode alone was more destructtive on the roots of maple seedlings than when combined with the fungi. F. oxysporum was less in urious than the other and decreased the nematode population as well, although the infection due to either of these fungi on the roots of seedlings were not so severe.

A majority of hyrcanian forests (north of Iran) are mountainous with the diversity of woody species being high. Therefore an ecological survey of altitude from sea level in relation with species diversity in these forests seems to be of paramount importance. For this purpose, the diversity of woody species in forest stands along with their natural regeneration has been surveyed by way of randomly choosing 18 sample plots of 0.5 hectare in different altitudes of Siahkal forests.The results obtained from the analysis of data in this survey, indicate that with increase in altitude, species richness decrease while species diversity and evenness continue to rise.Maximum species diversity is observed at an altitude range of 100-700 meter above sea level while the least diversity observed above 700 meter altitude. The distribution of trees in the diameter classes shows a "normal, decreasing feature distribution", which is a prime character istic in natural forests. Site conditions suggest that dominant and depressed trees represent minimum and maximum members respectively. Ninety seven percent of trees are healthy with only 3 percent damaged or wilted.Crown branching suggests that forked crown form is at the lowest proportion, while the proportion of broom shaped crowns is at a maximum, The study of branching in the first ten meters of tree trunk indicates that branchless trees are at a lowest proportion while multibranch trees are of the highest proportion. Moreover 59 percent of trees have a straight stem while 34 percent have crooked stems with the remaining 7 percent showing a combination of the two forms.With change in altitude from sea level, "diameter at breast height" and number of species per hectare do not change in a regular and organized manner. Sufficient quantity of regeneration (seedlings and sapling) has been observed at the altitude range of 1300-1600 meters above sea level. At lower and higher altitude ranges, the occurrence of regeneration per unit area was not satisfactory.

The present study deals with the socioeconomic obstacles in the way of implementation of forestry design operations in kiasar region. The statistical population was comprised of the males in 744 kiasari families, a total of 1770 men from among whom 2.5 percent were picked out to fill up questionnaires. Filling up of the questionnaires on an even and randomly basis was done through interview with the volunteers. The first hypothesis in the research was that no more than 50 percent of the population in the area was aware of the forestry design operations. Results revealed that only 23% of the respondents knew about the operations and therefore this first hypothesis was confirmed (P=0.01). As dissatisfaction of the people with the implementation of forestry design operations is concerned, results concluded from responses to questionnaires indicated that people do not welcome the operations as for the following reasons: Probability of intensification in occurrence of floods (100%), probability of degradation of recreational spots (76.67%), decline in conservation efforts (73.33%), and finally the probability of no increase in forest replantation, renovation and development (70%) the othe hypothesis was that more than 50% of the respondents would be in agreement with the impletation of research in forestry design if they would be thoroughly informed of the aspects. Results indicated that only 46.67% of respondents became in agreement and therefore this hypothesis was not confirmed.

A completely randomized experimental design was conducted to evaluate the effect of dietary astaxanthin on egg astaxanthin content as well as fertilization rate in Rainbow trout (Oncorhynchus mykiss) brood stocks .Different levels of astaxanthin in fish diet containing 0.07, 12.46, 33.33, 65.01 and 92.91 mg/kg constituted the treatments. Brood fish were reared under artificial photoperiodic system for a six-month period till sexual maturation, then prepared for artificial propagation. Homogenous sperm of four males (to avoid poor sperm quality they had been fed with diet supplemented with astaxanthin at a rate of 33.33 mg/kg) were used for fertilization. Female broods produced eggs containing astaxanthin, ranging from 2.035 to 29.79 mg/kg. There were significant differences observed among treatments as regards egg astaxanthin content (p<0.05). Although there weren't significant differences among experimental treatments as regards fertilization rate (p>0.05) but there was a significant difference observed as compared to control group (p<0.05). A significant regression relationship was observed between egg astaxanthin content and fertilization rate (p<0.05) that demons trated the positive effect of egg astaxanthiri content on egg fertility and also confirmed the hormone like role of astaxanthin in fish fecundity.

High unsaturated fatty acids HUFAs are of essential nutritional value in larval food, as these fatty acids play a very important role in survival of growing larvae. Therefore it is necessary to enrich the newly hatched Artemia Nauplli in order to improve HUFA content as well as DHNEP A ratio. Artemia urmiana contains a very low level of EPA (ω3) and only a trace amount of DHA (ω3), therefore it must be enriched before use.In enrichment through use of emulsion, a high increase in EPA as well as in DHA levels as compared to control was observed. During starvation period while in cold incubation, EPA level decreased initially but was followed by a later gradual increase whereas DHA level continued to decrease throughout incubation period. Due to this storing Nauplli for more than 24 hours after enrichment cannot be recommended, because the level of nutritional value would decrease to such low limits that it cannot be used as efficient and suitable larval food.

Golestan national park is one of the oldest protected areas in Iran as well as in the world. This park benefits from a high diversity of physical features as well as rich flora and funa due to its special geographic location. It is also visited by many tourists, because of its bio-diversity, natural scenic landscapes and lying along side Asian Highway.In this research, qualitative and quantitative criteria of design were obtained from and based on comp rehensives of Golestan National Park, design standards for outdoor recreational areas, national parks regulations as well as landscape ecology approaches.So, a design of Golshan outdoor recreational zone was performed on the basis of results, and targets (conservation, educational activities, and outdoor recreational development) and with a minimum of intervention in natural conditions.

Sawdust is an organic solid waste material of high adsorbing potential in removal of heavy metal ions from wastewater, so it can be used in treating industrial waste.In this study, the removal of copper, chromium, and nickel from laboratory prepared wastewater, through sawdust, was investigated. Waste water containing heavy metals was added was to sawdust to evaluate the rate of metal ion adsorption in different conditions of acidity, contact times and concentrations.The results indicated that the adsorption of these heavy metal ions increased with an increase in pH and reached a maximum at pH=5. In addition, percent adsorption depended on kind of ion, so that at pH=5 the percent adsorptions for Cu (II), Ni (II) and Cr (III) were 65%, 56% and 50% respectively. Adsorption increased with the initial concentration of metal ions and then decreased, because of sawdust saturation. Saturation capacity per gram of sawdust for copper, nickel and chrome ions was 28.2, 11.8 and 23.2 ppm respectively. Also adsorption increased with contact time. However, this process was rapid, and in the initial 10 minutes, percent adsorption got to between 45% and 65%. And finally the favorable needed time was determined to be 60 minutes.

Due to importance of Persian Gulf in exploitation and transfer of fossil fuels as well as the ongoing regional political events, there is always a trend of entrance of pollutants into this aquatic ecosystem that also end sup in the body of sea animals. Vanadium and nickel are two important indicators of oil pollution. Lengthy explosion to these elements causes serious harmful effects in human health, different harsh allergies being examples, just to name some.In this study the amount of these elements as well as their ratio (N/va) in S.Cucullata and P. radiate were determined. P radiata samples were collected from four stations in Hormozgan province's coasts as well as from Hormoz peninsula. Scucullata samples were collected from four stations in Hendurabi peninsula. Collection of samples was done in autumn and winter 2002. Following shell biometry, a digestion of samples was carried out using the international standard (Berman 1995, Method 7000). Ni was evaluated through atomic absorption, using philips Model PU9400.Vanadium was assessed using a Shimadez atomic absorption set, Model G670. The measurements were made for both crust and muscle in shells. The results indicate:Mean nichl and vanadium contents in S.cucullata are 6.32, 0.77, and in Pradiata they are 3.44 and 0.76 mg/kg-1 respectively.These element's content in shell as well as in tissue exceeds the standard ualues while at the sametime shell content being more than that in tissue. The only source of V is realized to be oil pollutants where as sources other than oil pollutants can cause Ni contamination.There was no relationship observed between Ni & V contamination, and biometry (size and weight). There was a significant positive corellation found between V content in shell and tissue. There exhists a significant negative relationship between Ni and V in tissue. A significant relationship is observed between Ni, V content in Scucullata shell and tissue. In S.cucullata there is also found a positive significant relationship between shell length and shell V content.Between tissue content of Ni and heel length in S.cucullata there exists a significant negative relationship.

Soda bagasse pulp was bleached, using sodium hypochlorite and sodium hydrosulfite sequence or vice versa (reverse sequence). The optical behavior of the bleached pulps was investigated through optical and thermal accelerated aging of the hand sheets. Some characteristics such as brightness (R∞), lightness (L*), yellowness (b*) and greenness (a*) factors as well as absorption and scattering coefficients of light before and after aging were assessed.Also, in this study, the effect of consistency (per cent) of pulp and Fe2+ ion and a chelating agent (EDTA) on yellowing of paper was determined. The results indicate that application of a reductive bleaching stage after oxidative treatment of the pulp will cause more brightness stability as compared to the reverse sequence.

Sugar cane bagasse is an alternative non-wood source of fiber for producing various grades of paper. In this study, a biotechnological approach was employed applied as pretreatment to produce pulp from bagasse. Bagasse from Khouzestan was treated with selected white-rot fungus, namely Ceriporiopsis subvermispora L-14807 in non-sterile conditions (temperature=27° C and relative humidity = 85-90%). Then, both pretreated and control samples were digested using 14, 16 and 18% alkali for 15 and 20 min. It was found that as a result of fungal pretreatment, kappa number decreased significantly (from 23.7 to 20.9) while yield loss being also observed (from 58.7% to 55/9%). Meanwhile, the results also indicated that fungal pretreatment improved paper burst as well as tensile strength, but reduced folding endurance. Optimum bio-pulp (high burst and high tensile strength) could be obtained by cooking fungal pretreated bagasse fibers for 15 min at an alkali concentration of 16%.

Increase in wood consumption has been accompanied by population increase. The importance of cultivated fast growing species and clones of poplar is indicated by the fact that many have been imported to Iran and cultivated in Gilan through recent decades.Among them some clones like Populous deltoids 77.51 are of better compatibility and higher wood yield. Therefore, it was paid more attention to by farmers as well as poplar culturists.Best wood utilization is found to be in close relationship with recognizing the species, anatomical characteristics, biometr as well as physical properties.Specific gravity in this clone is 0.388 gr/cm3 with average length and diameter of fiber of 946.95 and 25.4 microns respectively.Anatomical characteristics: wood is semi-ring porous, homocellular, vessels are single or jointed together in groups of double, triple or tetra bands.

This research was carried out to investigate germination in Artemisia aucheri. For this purpose, seeds were collected from Vard Avard/ Karaj in late November 2002. Experiments were performed in a randomized complete design in the seed laboratory, Natural Resources Faculty, Tehran University.Percent germination of seeds collected from three different altitudes were compared in dark as well as in light conditions and at two different times. Results indicated that percentage of germination at both times (December and next late May) at 2200m above see level was higher than those at 1800 and 2400m. Also, in light conditions it was higher than in dark conditions, but germination speed in dark conditions was higher. Comparing the percentage germination at two different time stages, it was found that it increased 10-17% when seeds were kept for six months from collection in fridge temperature conditions.

A knowledge of the mechanism of abiotic stress tolerance in wild species of grasses is essential during the first year after establishment in semi-arid areas. Perennial grasses are one of the keys to the economic and environmental sustainability of pastures as well as livestock grazing in Iran. There is a lack of knowledge about their drought tolerance during their initial growth stages and their response to re-watering during the first year of establishment. To evaluate the effects of soil water (field capacity, water holding and re-watering), a greenhouse experiment was conducted on root and shoot developmental initial growth stages and recovery of 36 populations of native cool-season grasses from 15 species of seven genera namely: Elymus, Agropyron, Secale, Hordeum, Bromus, Festuca, and Dactylis. All measurements except root dry matter and length were significantly affected by the treatments (P<0.05). Water stress decreased root and shoot dry matter (about 50%), whereas root to shoot ratio and recovery of dry matter increased at 22 and 43%, respectively. Decreasing soil water from FC (-0.33 bar) to wilting point (-15 bar), reduced relative water content from 78 to 46% for all species. Results indicated that Elymus elongatum and Bromus tomentellus were of the highest and lowest yield potentials under water and stress conditions, respectively. Drought tolerant genotypes, suchas Elymus repense and Elymus elongatoformis showed a higher root dry weight and responses to rewatering. Root extension and carbohydrate storage were associated with greater drought tolerance as wellas recovery yield.

Considering the importance of the country's rangelands in providing pasture for feeding domestic animals as well as in protecting the soil, it is necessary to find concrete measures on the basis of scientific findings and practical experience. Such measures can help the executive branch as well as the users in better and more efficient use of these resources. It is equally important to utilize suitable machines for mechanizing reclamation of impoverished rangelands. This will increase speed, accuracy and efficiency as well as save time and cost. For this purpose, proper selection of implement is essential. Among the machines used for pasture reclamation are planters. Their proper utilization, particularly use of suitable press wheels is very important due to the significant effects that compaction of the soil around the seed has on soil moisture preservation as well as seed germination and growth. In this research, conducted as a split plot experiment based on a completely randomized block design in three replications, the effect of five types of press wheels and two initial soil moisture contents (9.1% and 19.3%) on selected plant and soil parameters was studied. Soil texture was heavy clay-loam with some lime. Soil parameters under study included moisture content and bulk density, measured at the following time stages after planting: one week and two months, at 0-15 cm and 15-30 cm depths. Plant parameters included: 1) percent germination of sainfoin 2) percent emergence, and 3) plant dry matter. Using analysis of variance and Duncan's multiple range test for comparison of the means, it was determined that at both levels of initial moisture content, using a press wheel on the planter is essential. Furthermore, rubber wheels were found to be superior to the metal ones. The lugged press, wheel (type P3) performed better than all the others. The regular rubber wheel (type P4 without lugs) ranks next, having a significant difference with P3in the moist, but not in the dry treatments. Therefore, due to lower production costs, the regular rubber press wheel is recommended in dry soil 'conditions. Considering the parameters measured in this study, press wheels P1 (boat type), P2 (metallic with a groove), and P5 (metallic without groove) didn't exhibit suitable results.