IRANIAN JOURNAL OF NATURAL RESOURCES
Year:2005 | Volume:58 | Issue:2|Papers Count:23

One of the most important factors which affect the flooding behavior in every watershed is high rainfall. The daily rainfall data are the most available data with non-linear mathematical relations (between daily rainfall and short duration rainfalls) having been established and accepted in Iran. If there existed some relationships between daily flooding rainfall and altitude, the creating of precise mathematical models would be possible. Such asituation will facilitate precise estimation of peak flows.In this research 262 hydrographs were selected in three subwatersheds and their corresponding daily rainfal data extracted from 38 raingauges scattered all over their areas. The correlation cofficience between altitudes for raingauges and daily flooding rainfalls indicate that there are direct correlation at a confidence level of 1% for two atersheds and at 5% for others. Also the correlation between coefficient of variation (CV) in daily flooding rainfalls and altitudes were significant by linear negative regressions at a confidence level of 1% in one subwatershed and at 5% for others. Also the correlation between peak flows of hydrographs and corresponding daily flooding rainfalls was significant at a confidence level of 1% in all subwatersheds. This research indicated that introducing altitude as a variable factor in producing mathematical equations for short duration rainfalls (from daily rainfalls) can help improve the models of estimation of peak flows at ungauged watersheds.

Physical and chemical properties of sediments are affected by source area lithological formations. If these deposit materials exist in flood spreading systems or artificialrecharge basins the infiltration rate will be decreased. Therefore, the rate of infiltration in alluvial deposits is indirectly related to source area lithology. Suitable areas for determining these relationships were selected. In this research, 8 small watersheds with relatively uniform lithology at upstream of Band-Sars (Traditional Flood Harvesting Systems) were selected in 20 million hectares in Khorasan province. Infiltration rates in Band-Sars as well as in control areas were determined. The results show that the infiltration rate in the 8 regions are completely different and related to upstream lithological formation. Coarse grained sedimentary and igneous formations have little effect on the decrease in infiltration rate.

There presently exists a great need for information in regard to an understanding of why and the extent by which sediments are carried in water through rivers. This information is indispensable in an evaluation of: rate and pattern of erosion; physical and chemical weathering; sediment  transport from the higher to lower slopes in a watershed; water pollution (particularly non local pollutions); sediment balance determination, and finaly proper management of catchment basins. Sediment discharge is many times a good criterion for evaluation of basin's yearly erosion.Numerous methods have been presented for evaluation of suspended sediments but the results widely differ from each other. The most important impediment, however in all these methods of evaluation is a lack of dependable observational data. Availability of rather consolidated and consistent data in the hydrometric station of Gazogly located on the upper elevations of voshmgir Dam, .Gorganrud catchment basin provided the means to determine the accuracy and precision of the evaluation methods in suspended sediment surveys. By use of different ways of "systematic, random-systematic and plain systematic" along with varied yearly frequencies (12, 26, 25, 104), and by taking into account flow classification, sampling was made from a population of observational data.Suspended sediment was then determined for anyone of the samples by 21 different methods (different with regard to rating curve and /or discharge). Finally, after calssification of the methods and by use of the two parameters of standard deviation of errors and evaluated error relative to consolidated observational data, the different methods were compared. Results indicated that the method of "a combination of average daily discharge with the rated curve of calssess, (group's) median" was of more accuracy and precision, and therefore selected as the most proper method. Also in this method of sediment evaluation, randomized systematic sampling responded in a more appropriate way than the others. Altogether, the method of sampling from classified flow together with additional readings of high and medium flows reduces the error to and extent of 50% as compared to sampling method devoid of grouping (classification).

Soil conservation service-curve number (SCS-CN) method is one of the most employed methods for computing discharge as well as surface runoff from watersheds. Recent studies show that this much-used method is susceptible to difference in curve number. As a result, much caution is recommended in its application. In this research the above-mentioned method was used and it was found that the asymptotic method would give a better SCS Table method for determining curve number. Results also reveal least peak-flood differences between observed and calculated discharge in the asymptotic method. The discharge while using SCS Table method in different antecedent moisture conditions shows a larger difference with the observed discharge.

Effect of thinning on Atlas cedar (Cedrus atlantica Manetti) was investigated in a man-grown forest in Kelar-Dash tregion, north of Iran. In this forest, a silvicultural practice, namely thinning was carried out in five replications, each of 200m2 area for removing 25% of tree basal area; besides that, five replications, each of 200m2 were considered as control. The results in a 5-year investigation period revealed that mean diameter growth in C. atlantica was twice as much in thinned stand than in control (p<0.01) but statistical difference in mean height growth in the two stands was not significant. Vitality quality in most of trees was satisfactory but no significant difference of this term could be observed in the two treatments. Fruit bearing was significantly more abundant in the thinned stand. Plant diversity, presented by broadleaves ingrowth as well as herbaceous species, was more conspicuous in the thinned stand.

Root growth potential (RGP) is the ability of a seedling to produce new roots (white roots) in a defined period and under defined conditions. Pinus taeda is one of the most important conifers, planted in Guilan province in an extensive scale. Therefore a study of its characteristics, specially RGP has a great positive effect on the production of its seedlings in nursery. The experimental design used is a complete randomized design (RCD) with 6.treatments and 5 replicates. Results indicated that a bare root seedlings under fertilizer treatment conditions had highest value for RGP. Container seedlings developed a greater amount of root and were superior in some other variables studied, but the root system was strongly twisted. Root pruning was demonstrated to have no significant effect on root growth potential.

Forest road network is one of the most important forest management projects, that plays a great role in timber transportation as well as other forest services such as tourism, hunting, etc. Essentially water accumulation on forest roads can be the main reason for road destruction through erosion and decrease of road strength. Generally forest roads are constructed in humid and rainy zones where water is one of the most important factors in their erosion, therefore drainage is important for decreasing the destructive effects.The results in this research indicate that, drainage pipe diameter in talwegs could be estimated by considering discharge in talwegs, rain intensity, runoff coefficient, area and hydrological conditions.Pipe diameter for conducting road canal water is determined on the basis of canal bed susceptibility to surface erosion, canal cross section and discharge. Road location on the foothill, slope length, and water discharge play the main role in determining the distance between pipes, the more the height of road, the more will be the distance between pipes.

In Kelarabad plain forest with an area of 59.39 ha, information and data about vegetation (herbs and bearing seedling species) were collected from 77 sample plots (20mx20m) which were then analyzed by using Bran-Blanquet combined scale and through use of TWINSPAN program. The data were Classified to determine 4 ecological groups. Some physical, chemical and biological characteristics of soil, such as texture, SP, EC, TNV, %OC, N, P, K, pH, CEC, and earth worm biomass were determined. By, use of PCA analysis, the co-relationship as well as distribution in each ecological group of environmental factors were determined with respect to the 1stand 2ndaxes separately. It was noticed that the 1st and 4thecologicalgroupshad the highest co-relationship with the 1st axes whereas 2nd and 3rd ecological groups demonstrated the highest co-relationship with the 2nd axes. pH increased from the 1st group toward the others. Each of these four groups can be identified by the following environmental factors: earth worm biomass, OC% and Sand% for the 1st group; Sand% and Silt% in the 2nd group; P and Clay% in the 3rd group, K in the 4th group. So it is concluded that physical characteristics influence the most effects on formation of ecological groups in Kelarabad plain forest.

The effect of natural dietary zeolite (at a level of 3%) on the growth of red tilapia and lettuce seedlings in an aquaponic system was evaluated. The experimental unit was a recalculating system consisted of a fiberglass tank with 120 cm (width) x 80 cm (Length) x 100 cm (height).equipped with three hydroponic troughs (110 cm L x 30 cm W x 7cm D) and a submersible pump (Model Aqua, 1500) with the power of pumping 30 11min of water used for recycling water from the rearing tank through the hydroponic troughs. At the initiation of the experiment each fish tank was filled with 640 liters of gentle aerated tap water, then 50 pieces of red tilapia juvenile with a mean body weight of 6.23±0.10g were introdued into it. After two weeks of initiating the experiment, 42 cups, each containing one-week aged seedlings of lettuce were introdued in the hydroponic troughs in each experimental unit. The experimental design was a completely randomized one in triplicates for each treatment. In the investigating treatment, fish were fed with a dietary zeolite and in the control treatment they were fed with a zeolite tree diet. The quality in both diets based on biochemical composition (protein, fat, fiber and total energy) was the same. The individual weight, biomass and mortality of fish were not significantly different (P>0.05) among treatments at the end of experiment. Mean individual body weight in fish was 32.50±2.00 and 32.80±0.02 in treatments control and dietary zeolite, repectively at the end of experiment. Utilization of dietary zeoilte increased the yield of lettuce significantly (p<0.05) as compared to control. Lettuce yield was 275±83 and 768±67 in treatments control and dietary zeolite, receptively. The concentration of total ammonia was significantly lower (P< 0.05) in fish rearing tanks in treatment with dietary zeolite at the end of experiment. The results in this research indicated that use of a dietary zeolite (at a level of 3%) evidently increases the growth of lettuce seedlings in an aquaponics system and emphasized the need for a further research to investigate the effect of different levels dietary zeolite on the growth of red tilapia in an aquaponic system.

To evaluate the toxic effects of pesticide Endosulfan in fish, acute toxicity tests were carried out in valuing common carp (Cyprinus carpio) of 5-20 and 21-40 gr, using static water of 21°C and employing Organisation of Economic Coopration and Development (O.E.C.D) method.Mortality limits of 0.0002-0.0022 and 0.001-0.0046 mg/lit were found in fish of 5-20 gr and 21-40 gr, respectively. The LC50 of 0.0061, 0.0029, 0.0016 and 0.0009 mg/lit were obtained in fish of 5-20 gr within24, 48, 72 and 96 hours of post- challenge, respectively, while those in fish of 21-40 gr were 0.0079, 0.0053, 0.0035 and 0.0024 mg/lit, respectively.The affected fish showed pale colour, irregular swimming behaviour, whirling and bottom sitting. Following a temporary recovery, fish showed sufferings of severe convulsion and respiratory disorder, resulting in death within a short time after challenge.Histologically, there were hyperemia and inflammation of secondary lamellae in the fish challenged with lower doses of the pesticide whereas a general necrosis was observed when fish were in contact with higher doses. Similar histopathological changes were observed in the kidney and liver tissues.According to the mortality limits and LC50(less than 0.1 mg/lit), this pesticide should be considered as a very highly toxic chemical for common carp, causing a rapid and accumulative mortality in fish.

The goal in this study, was to monitor motility duration of Mugil cephalus spermatozoa in different extenders. Fifteen extenders were used in the study which include: Coelomic fluid of four different concentrations (nondiluted, 0.1%, 1% and 10%) BSA (Bovine Serum Albumin) with two concentrations (10mg/ml, 30mg/ml diluted in distilled water), Two saline extenders: 1. (45mMNaCl, 5mMKCl, 2.5mMTris, 19mMGlycin, pH8), 2. (500mMNaCl, 3.1mMKCl, 0.2mMTris, 3.4mMCaCl2, pH7.5) Two solutions of NaCl (50mM, 250mM) that were used following centrifuging of milt and separating of spermatozoa. These solutions were used to replaced seminal fluid.Fertilizing fluid with 5 different salinities of 10, 15, 20, and 25ppt along with 32ppt, used as control. The duration of sperm motility varied widely in different extenders. Spermatozoa were inactive in coelomic fluid of different concentrations, in either of BSA, saline extender number 1, both solutions of NaCl as well as fertilizing fluid with salinity of 10ppt.Mean duration of sperm motility ranged between 77.6-149. 3, 26.66-68.6, 43.33-132.3, 59-135.3, and 73.33-138 seconds in saline extender 2, fertilizing fluid with salinities of 15, 20, 25, 32 (control) ppt. respectively. The longest duration of sperm motility was achieved in saline extender number 2 namely (500mMNaCl, 3.1mMKCl, 0.2mMTris, 3.4mMCaCl2, pH7.5).Results Finally indicated that M. cephalus spermatozoa are active in hyperosmotic solutions.

In this study, the possibility of using oak bark's extractives as phenol-formaldehyde resin replacement was paid attention to in partic1eboard manufacture. The variables were percent replacement, press temprature as well as press time. For quality characteristics determination, water absorption & thickness swelling of samples (after2and 24 hours) along with bending strength (modulus of rupture) and internal bond properties of boards were evaluated according to DIN 68763.Results indicated that the best conditions for obtaining the most desirable physical and mechanical properties in PF resin replacement with oak phenolic compounds were obtaind in treatments of 30% replacement, 180°C press temperature, 7 min press time along with 2% zinc-acetate as catalyst.

The effect of transition metal ions on optical properties of hydrogen peroxide bleached chemomechanical pulp of a mixture of northern Iran hardwoods was studied. Hand sheets were made using deionized water, tap water and water containing Al+3, Cu+2, Mn+2, Fe+3, Fe+2 ions. Also, the effect of DIPA Spray on minimizing the impact of these metal ions in the processing water on brightness as well as its stability both before and after accelerated photo aging was investigated. The results indicated that brightness loss due to metal ions is as high as 4-5 points. It was also shown that using DTPA in small amounts could recover the brightness that was lost due to the presence of transition metal ions.

The objective in this study was to determine Celcure (A.C.C.) of 3% concentration retention and penetration in 150×l0×l0cm specimens possessing moisture contents of 12, 20 and 40% and taken from the lower, middle and upper (below the crown) portion of poplar stem (Populus nigra var. horizontalis). Impregnation was performed using a modified Ruping Process in that the process was applied three times but the main pressure stage being reduced to one hour. The results are as follows: Retention means at 12% moisture content were 85.75, 108.25, and 133.5% from collar to the crown, respectively. At 20% moisture content these values were 60.50, 71.50 and 85.5% while at 40% moisture content they were 41.35, 50.75 and 49.67%, respectively. Analysis of variance showed that there were a significant differences among retention means at different heights as well as different moisture contents at a 1% level of confidence.Penetration increased with increase in retention as well as height. At 12% moisture content, maximum penetration depths were 6.5, 6.6 and 7.6 cm, at 20% moisture content: 4.2, 4.3 and 4.9 and at 40% moisture content: 1.4, 1.7 and 1.8cm at the three above mentioned heights, respectively.It was also found that dry density increased with retention of preservative at any moisture content as well as any height, this increase being dependent on the amount of retention. Analysis of variance showed that there was no significant difference between the dry densities at the three moisture contents but this was not the case for different heights. The cross sectional preservative distribution area wasn't uniform in most samples. This can be attributed to the presence of wet spots which counteracted the proper penetration of preservative.

This reaserch was conducted to investigate the effect of application of oxidative chemicals (nitric acid & hydrogen peroxide) on wood particles surface, using FTIR (Fourier Transform Infrared) spectroscopy. P. deltoides particles were each treated by two oxidizing agents; nitric acid and hydrogenperoxide at three levels of application. Then, in order to investigate the effect of the oxidation on wood particles, the spectrum of oxidized and those of control were taken while using FTIR spectroscopy F.TIR spectrum in treated samples exhibited an increase in the intensity of the absorbtion bands at 1730-1740cm-las related to carboxyl(COOH) group and in comparison with control.Therefore, as indicated by the spectrum, increasing oxidation rate increases absorbtion in COOH group. In addition, absorbtion rate in COOH group samples in nitric acid treatment is more pronounced than in samples treated with hydrogen peroxide.

This study was carried out to create and compare vegetation maps based on geomorphology and physiography units methods. An area of about 16230 hectares comprised of four sub-watersheds of Arton, Kash, Zidasht and Kalanak were selected in Taleghan region. In Geomorphology method different maps of hipsometry, slope, aspect, geomorphologyical facies and lithology were prepared. Created maps were integrated to obtain a uniform terrain mapping unit. Each unit in this map was takenas a base of management and measurement for vegetation parameters. In Physiography method, map of primary vegetation type was obtained using 1:20000 areal photographs. This map was modified, based on field observations, to produce actual vegetation map. Then vegetation parameter assessment was conducted within each vegetation type. Arcinfo, Idrisi and Arcview softwares were used for integrating and digitalizing maps. Vegetation maps obtained from either of Geomorphological and physiographical methods were compared. According to the results, in spite of expectations, in some terrain units there were more than one vegetation type or in some vegetation types more than one terrain unit was found. In a general sense, there did not exist a strong relationship between vegetation types and terrain mapping units in the study area.

To achieve an acceptable level of animal performance, a matching of animal feed requirement with the needed quantity of forage, with due attention to forage quality, is essential. In this study, feed requirement of Zel race sheep, grazing on mazandaran rangelands was estimated. For calculation of the ratio of ram to ram + lamb a number of 10 rams, ten 3-month old and ten 6-month old lambs were weighted, the respective weights being recorded and then used. Overall average sheep weight was found as 30.48 kgs. The average weight for the ten rams, ten 3, and ten 6-month old rams were 47.67, 19.75, and 23.53 kgs respectively. The ratio of ram to sheep weight was found to be 1.56 and the ratio of 3 and 6-month old lambs to sheep (Zel race) were 0.67, and 0.7 respectively. For a determination of animal feed requirement, based on forage quality, samples of plant species in different phonological stages were taken for in-vitro analysis. Analysis and assessment of crude protein, digestibility and metabolizable energy were carried out. In vegetative phonological stage, the highest protein percentage was recorded for Medicago sativa whilst the highest metabolizable energy for Medicago coronata. Taking into account the distances between sheep yards and rangeland, topographic conditions, vegetation density, as well as distances between animal watering stations and additional500.10 was added to the pre-calculated animal feed requirement, using the formula ME =1.8+0.1 W where W stands for live weight. Based upon forage quality in any of the phonological stages as well as plant nutritional composition, the daily forage requirement of unit animal was determined to be 0.8, 0.91, and0.97kgs/day in the plant phonological stages of vegetative, flowering and maturity, respectively.

Information regarding forage quality and its variation in different climatic zones and at various phenological stages can help a range manager to determine daily animal requirement which in turn is essential in an evaluation of grazing capacity. In order to determine forage quality, five species of vegetation namely; Agropyron tauri, Agropyron trichophorum, Bromus tomentellus, Festuca ovina and Hordeum bulbosum were collected from 18 vegetation communities of 8 climate zones and at three phenological stages of vegetative, flowering and seed ripening. Plant samples were analysed to determine N prcentage as well as ADF. Metabolizable Eenergy was assessed as a forage quality factor.Variance analysis was applied to data. Results indicated that Metabolizable Energy is significantly affected by species, phenological stage as well as climatic zone.

To study the effect of irrigation on yield and green growth period in nine range species in climatic conditions of Urmia, an experiment was conducted as split plots in a randomized complete block design with three replications at the Agricultural Research Station, Urmia University. Main plots were consisted of three irrigation regimes: non, few and several irrigations. Nine grass species of: Arrhenatherum elatius, Bromus inermis, Festuca pratensis, Festuca arundinacea, Agropyron trichophorum, Secale montanum, Bromus tomentellus, Agropyron desertorum and Elymus junceus. Effect of the plant treatments on yield as well as green growth during three growing seasons were evaluated. Analysis of variance along with mean comparison between treatments indicated that there were significant differences among irrigation regimes for plant species. There was also considerable variation observed among species in dry matter yield. Maximum dry matter yield with 7482 kg/ha belonged to Arrhenatherum elatius in several times irrigation regime. Dry matter yield in the above mentioned plant was reduced by 25% in natural rainfall condition as compared with the several times irrigation regime. Minimum dry matter yield was 135 kg/ha obtained from Festuca pratensis in natural rainfall conditions, however, at several times irrigation regime dry matter yield increased by 85%. The green growth period did not follow any particular trend in irrigated plots, but the greennes period in Secale montanum was more than that in the other plants in non irrigated plots, while it's dry matter yield decreased in irrigation conditions. In conclusion irrigation and selection for high mean productivity in range plants can present a beneficial effect on yield in areas where rainfall is not adequate.

Variation as well as amount of mineral elements fixed by Salsola rigida along with their effects on soil surrounding the plant in desert regions have been investigated in this study. In any of typical area, four plots, each of a 100m2 area were taken and in each plot, following a study of plant covering parameters, two profiles(one under) salsola plant and one in between plants) were dug. Soil samples (72 in total) were taken from each profile at three depths of 0-10, 10-25, and >25 cm. The samples, either plant or soil were analyzed in the laboratory for 19 soil and 6 plant parameters. Analysis of soil data indicate the important findings in which are:a) Soil EC is the prohibitive factor in plant's spread. b) Optimum EC was determined to be less than 8 ds m-1. Introduction of the plant is not recommended in areas with an EC of more than 11 ds m-1 c) the plant is sensitive to high doses of lime in soil. d) Plant cover is harshly reduced with excess Na and Cl in soil. e) Ca and Mg content in areas with low plant cover is substantially more than that in areas with substantive Plant cover. The most important effects of the plant on soil through increase, in soil elements are: a) increase in organic matter which in the long run improves soil structure, b) increase in soil N as the most important nutrient needed by plants, c) increase in K which in turn increased the nutritive value (increase in protein) of plant species, d) considerable increase in RC03 in plant's surrounding soil. Determination of macroelements through leaf analysis revealed: a) the amount of elements present in leaf is not to the extent that can harm the cattle, b) average Ca, Mg, and Na content in top branches and leaves is more in areas with good plant cover as compared to the remaining two areas, c) there exists a significant correlation between Ca, Mg, and P in soil and in biomass. Taking into account the considerable adaptability of this plant species to adverse climatic and ecological condition, proper establishment and reproduction, this plant can be recommended and used as a valuable and important species in desert control, plant cover improvement and forage provision in nomadic rangelands.