Journal of Agricultural Sciences and Natural Resources
Year:2008 | Volume:15 | Issue:1 (SPECIAL ISSUE ON NATURAL RESOURCES)|Papers Count:28

The main purpose in this study was to assess the role of membership in forestry cooperatives in the revitalization of forestry resources in the western part of Mazandaran province. This was a correlational-descriptive study conducted through survey method. 75 members of forestry cooperatives and 76 of non-members consisted the sample of the study. Validity and reliability of the study's tool were conformed through appropriate methods. The result of "t" test showed that the two groups viz, members and non-members had significant difference of participation in revitalization of forest resources. According to correlation analysis there were significant relationships between membership & participation in revitalization of forestry resources .The result of multivariate regression Analysis indicated that 62.2 percent of the changes in revitalization were explained by their participation in conservation and development of forest resources.

Awareness of forest tree density is one of priorities that managers for assessment forest resources, timing treatment silviculture and planning must access to it. This information generally are produced through fieldwork, which in large areas takes much more time and cost. Also, remote sensing and interpolation methods can be suitable ways to estimate forest tree density. In this study, 99 plots with 60m×60 m were set down with systematic cluster sampling method at the study area. In each plot, information of tree density and geographic coordinates of each plot center were recorded. The regression model with ETM4 and ETM5 as independent variables were better predictor of tree density (RMSE=170.13) than other combinations of ETM+ bands and vegetation indices. In geostatistics methods estimation was preformed by ordinary kriging using spherical model cross validation results indicated that kriging could make a precise estimation (RMSE=201.768). The results of this research showed that in tree density estimation, the regression model was lower RMSE than ordinary kriging. The difference RMSE between regression model and ordinary kriging in local scale not significant but in large area regression model has good results. Generally, estimation of tree density using satellite data offers advantages such as using in large area, a reasonable cost and decreasing sampling.

Some biological aspects of semen were investigated in the ship sturgeon, Acipenser nudiventris, by determination of seminal plasma indices (ionic and organic composition), osmolality and their relationships with spermatozoa motility. Seminal plasma contained 65.19±39.93 mmol/l Na+, 4.43±1.02 mmol/l K+, 2.41±1.49 mg/dl Ca+, 7.52±3.61 mEq/l Mg2+, 0.196±0.124 mg/dl protein, 27.35±5.83 mg/dl cholesterol and 5.16±2.15 mg/dl glucose. Semen spermatocriet was 7.54±3.90%, pH 7.70±0.56 and duration of spermatozoa movement 383.06±161.89 second.The Sodium/Potassium ratio was 14.71. The osmolality of seminal plasma ranged from 25 to 85 mOsmol Kg-1. There were no significant correlations between ionic, organic composition and osmolality of the seminal plasma and spermatozoa motility (P>0.05), But there was a significant negative correlation between glucose and K+ concentration (r=-0.765, p<0.01). There were also significant positive correlations between Na+ concentration and spermatocrite (r=0.643, P<0.05), and osmolality (r=0.657, P<0.05). Consequently, although there were no definite correlations between seminal plasma indices and spermatozoa motility, it was concluded that a higher K+ content has negative effect on glucose content. This study confirms again that Na+/K+ ratio in sturgeon seminal plasma is higher than that Salmonids and Cyprinids. This parameter, probably, explains the longer duration of spermatozoa motility in sturgeon in comparison whit that in Salmonids and Cyprinids.

In spring of 1999, 80 specimens of Vimba Vimba persa from 3 ecosystems were collected including: Gorgan-Rud River (21 specimens), Shirud river (29 specimens) and Anzali lagoon (30 specimens). 27 Morphometric, 15 proportional morphometric and 10 meristic characteristics were examined. Morphometric characteristics corrected and standarded before analysis for reduce error of allometric growth. Within the morphometric characters, nine factors accounted for about 79% of variation within individuals of the three populations, In the case of meristic characters, four factors accounted for 64% of variation within populations, as far as proportional morphometric characters are concerned, six factors accounted for 84% of variation within populations. In most morphometric characteristics and some meristic characteristics showed significant differences between populations (P£0.05). Principal components analysis showed vimba migratory populations were not completely separated, but they probably belong to different populations, that might be due to different ecological conditions which results in different immigrants make up each year. In this study with concerning size differences in specimens, morphometric characteristics were the best characters for populations separating.

Lipid quality changes of silver carp surimi (Hypophthalmichthys molitrix) were investigated by measuring moisture content, total lipid content and oxidative and hydrolytic rancidity during 6 month frozen storage at-18oC. For making surimi, silver carp mince were produced from fresh fish, then it was washed 4 times with ratio 4:1 (w/m), (firstly, twice with distilled water, secondly, twice with 0.3% NaCl, each time for15 min) at about 4oC. Then, it was mixed with a cryoprotectant consisting of 4% sucrose, 4% sorbitol, 0.3% polyphosphate (a blend of tetra sodium pyrophosphate and sodium tripolyphosphate with ratio 1:1). The produced surimi was packed in Ziploc bags and frozen at-35oC and stored at-18oc for 6 months. According to the results, The content of free fatty acids (FFA) increased during 6 month frozen storage at-18oC (P<0.05). Further more, after a decreased in the 2nd month, the content of thiobarbituric acid (TBA) also increased until 6th month. However the values of TBA during 6 month frozen storage were very far from spoilage stage. In addition moisture content and total lipid of mince did not change significantly during 6 month frozen storage.

In an 8-week feeding trial, two attractants (Aspartic acid and Alanine) for increasing food palatability and acceptability were added to juvenile beluga (Huso huso) diets at different levels in order to evaluate their effects on growth and survival rate. In this trial that was carried out in Shahid Marjani center of sturgeon hatcheries and cultivation, three different dietary levels of attractants (0.5%, 1% and 1.5%) were taken into account. The trial was carried out in 500 liters PVC tanks which were filled with about 350 liters of water. 20 juvenile beluga (with average weight 21.2±2.12g) were stocked in tanks and fed up 4 meals a day. Growth and survival factors were analyzed at the end of trial period. The results showed that the addition of attractants in diets led to more improvement of body weight increase, weight increase percentage, specific growth rate (SGR), daily growth rate (DGR), daily growth index (DGI), condition factor (CF), price index (PI) and decrease in food conversion ratio (FCR) than control treatment. The best values of improvement of growth index were achieved at dietary level 0.5% Aspartic Acid. There was no significant difference (P>0.05) in survival rate among experimental groups.

Age structure, growth, reproduction and feeding habits of sand goby Neogobius fluviatilis pallasi, were studied in the Zarrin-Gol River (Eastern Alborz Mountain) between October 2005 and September 2006. Both sexes included five age groups (0+-4+). The Maximum lengths were 121mm (TL) in males and 108mm (TL) in females, both were 4+ years old. The most frequent ages were 3+ and 2+ in males and females respectively. There were no siginficant differences in sex ratio from unity (P<0.05). Growth model was negetive allometrice for both sexes (b<3). The highest values of condition factor were observed in early September. After 1+ year age, the males showed higher value of growth rate than females. Average absolute and relative fecundities were 508.47 and 61.27 respectively. Considering GSI, reproductive season of sand goby in Zarrin-Gol River is March-April. The most frequent food items in gut contents were Trichoptera, Mollusca, Chironomidae and Gammaridae, and according to Ivlev index, the first three items showed positive values.    

In this study the effects of GnRHa, HCG and pituitary extract injection on spermatological parameters¬ (motility duration, percentage of motile spermatozoa, spermatocrit, sperm density, milt volume, pH) and sperm quality was compared in goldfish (Carassius auratus) males. Fish injected with hormonal GnRHa, HCG and pituitary extract with 10mg kg-1, 1500 IU/Kg-1, 3mg/Kg-1 respectively. There were a highly significant difference of seminal plasma pH among treatments (P<0.01), as the highest value of pH observed in treatments GnRHa and pituitary extract (9.26±0.30, 8.36±0.20) respectively. There were a highly significant difference for percentage of motile spermatozoa among treatments (P<0.01) as the highest value percentage of motile spermatozoa observed in treatments GnRHa and pituitary extract (85.07±3.20, 90.60±9.56) respectively, but there was no significant difference (P>0.05) for motility duration among treatments. There was a significant difference of spermatocrit among treatments (P<0.05), as the highest value of spermatocrit observed in treatment of pituitary extract (59.90±10.96). Likewise there were significant difference of sperm density among treatments (p<0.01) as the highest value of sperm density observed in treatment of pituitary extract (12.50×109 spermatozoa/ml semen). There was a significant difference about milt volume among treatments (p<0.01) as the highest value of milt volume observed in treatments GnRHa and pituitary extract (1.26±0.40, 1.05±0.13) respectively. The present study demonstrated that hormonal GnRHa and pituitary extract more effective on spermatological parameters compared with HCG treatment groups.

Timber and wood products are affected on the country economical because the products do improve surplus value and employment. Review is showed that their competitive powers are lower than foreign products but manufacture order is successful. Therefore, the basic of questions as fallow: how timber and wood products export and import are trend? Since, the research methodologies are analytic and approximate and forecasting methods (for example; trend and regression formulation) were used to establish. The result of; Orders forecasting data are reliable even with height MAPE, because MAD, bias and coefficient of determination are appropriate in here. Trend method is more careful than others. Some orders exports and imports will increase trend for example; exports and imports totality and timber order. Probability, the products imports totality will over 200 million and exports totality will over 14 million USA dollar in next years (latter of 2008). Some products (for example; particle board order imports) trend by dollar and kg. amount are conflict, probability, because the products price are oscillate and these weight amounts are decreasing and these products tariff change to depreciate tariff. The products trade will flourish in next decade because some orders exports and imports as favorable trend will increase. Negative effects (on the employment and surplus value) related to products imports increase will dissolve by afforest and massive material (timber, log) imports increase.

In this study, the dimensional stability and mechanical properties of three-layer particleboard produced from propionylated bagasse particles were investigated. Bagasse was propionylated without using any catalyst and solvent at 120°C for 4 hours. Bagasses with two sizes (fine and course) were treated. The maximum weight percentage gain (WPG) was 28.2. This maximum WPG was obtained when the fine particles were treated with propionic anhydride. Treated and untreated bagasse particles were pressed into three-layer particle boards using phenol formaldehyde (resole type). The mechanical and physical properties of the boards were tested. The dimensional stability of the particleboard made from unmodified bagasse particle was low. The particleboards made from propionylated bagasse particles were more dimensionally stable than the control boards. The module of rupture (MOR) and internal bond (IB) of the particleboards were decreased due to propionylation.

In order to determine attractiveness of plants for honeybees and setting beekeeping calendar, an area about 4600 ha, in Polour range lands was studied. The limitation of the region specified on the topographic map (scale: 1:50000). The representative site selected by asking from beekeepers. Regular visits were carried out in flowering period of plants. The plants which used by honeybees were identified with the methods of direct observation. At last 32 plants from 27 geniuses and 15 families were identified wich were used by honeybee. For determining the attractiveness of plants using by honeybees, time and number of standing of honey bees on each plant measured in 8 stages, 3 times in a day in 3 days interval, in 5 minutes and fix 100 area of canopy cover of plants. By combining the two factors (time and number), attractiveness index determined. So, the plants classified in 5 groups: 6 had excellent attractiveness, 7 good, 6 fair, 7 poor and 6 were very poor. In order to set beekeeping calendar, the score of plants were multiplied in canopy cover combination. At last the total score of these plants were computed in their flowering period. According to the flowering period of plants, the stages of flowering periods of honeybee plants that have large numbers of attractive plants were determined as the time of moving beekeepers to Polour region. This time was from first 10 days of June to first 10 days of September.

Changes in rangeland vegetation, soil and water resources are created by natural disturbances or management. Such changes may have determinant affects on type of plant community. Shifting in structure and function of rangeland ecosystems make the ecological boundaries that are named as threshold. Managers can separate these thresholds by ecological indices. In these rangelands, critical thresholds were investigated according to structural and functional differences of rangeland ecosystems. For determining ecological thresholds we assessed the stability, infiltration and nutrition recycle as functional properties and volume of canopy covers as structural property by rangeland health model. Sampling is done on the five distances of three rural (1000, 2000, 3000, 4000 and 5000 meter) in Golestan province. Results showed, in 4000 meter distance, changes are noticeable and critical threshold of these rural was in 4000 meter distance. Indices in 5000 meter was very high than 1000, 2000, 3000 and 4000 meter because cattle every day return to rural and grazing these area frequently. According to results, in management of ecosystems can use from structural and functional properties as a tool.

Considering the importance of applied environmental studies and preservation aspects, this research was carried out in 2004 using samples from 31 Tehran province livestock slaughterhouses and measuring the concentration of biochemical and chemical oxygen demand (BOD, COD) and total Coliform at inlet and outlet of wastewater treatment systems. Then, total emission of pollutants per tone of meat production and 1000 animal units of slaughtering were derived as the pollution indices. All pollution parameters and indices were compared between slaughterhouse groups and existing treatment systems. Based on the results, only 6.5 percent of firms follow the environmental standards. In comparison, the mechanized and biologic groups were better, while the traditional and public units were the worst in pollution. On the other hand, the paired t-test showed that the treatment systems were statistically effective in reducing the pollutants. Finally, establishing mechanized units and privatization of public units as well as changing the government's role from execution to supervision and policymaking are recommended.

Probability and the large of important floods must be estimated and the effects of flood with use of suitable methods and special installations must be controled For prevention of damages resulted from the occurrence of flood. In additional to that above mentioned, the effect of reservoirs from the point of flood volume and rate of reduction of peak discharge must be estimated in down stream. HEC_HMS Hydrological model has been designed for simulation of rainfall_runoff process in watershed. By setting the data of reservoir, simulated flood hydrograph will be observed if reservoirs is constructed and the effect of reservoir for flood control will be recognized. The purpose of this research is to study performance of Nowkandeh Multipurpose dam for flood control and reduction of peak discharge. Thus the necessary parameters for running model related to one-hour rainfall in after and befor construction of reservoir was introduced to the model. The results of running model show that constructed reservoirs influence in reduction of inflow peak discharge and decrease from 40% to 83% peak discharge in different return periods. In additional to, the effect of reservoirs in reduction of inflow peak discharge decreases corresponding to higher return periods.

Soil erodibility is a dynamic-soil property that changes with time, soil moisture, tillage, and animal activities, biological and chemical factors. According to spatial and temporal variability of soil erodibility and being constant for interested scales in most sediment and erosion models, in this study comparison of mentioned methods with consideration of its spatial variability considered. So interested network including nested–systematic in given location designed with taking 26 unit works and 101 polygons into consideration at GIS. Geostatistical analysis for all variables, those are effective in soil erodibility were taken place. Average of soil erodibility in the studied area with Geostatistical, Conventional methods and MORGAN-FINNEY was 0.6, 0.4, and 0.62 respectively. Two last methods allocated 13 and 3 soil erodibility amount respectively. Whereas in soil erodibility geostatistic method allocated 74 amounts and has been gradually changed. Spatial variability of soil erodibility with regard to coefficient of variation and minimum area of homogeny unit proved. Statistical test of nested between two land capability units in the study area and soil erodibility amount has shown significantly differences in sampling different places.

Soil is one of the most important elements of the environment. Soil erosion is an unavoidable phenomenon that increasingly destroys soil and pollutes water. The intensity and type of soil erosion are mostly functions of climatic, topographic, soil and land use characteristics. The role of land use in this connection is high, due to dominating role of the humans in landscapes.  In this study, the role of unsuitable land use in causing or augmenting soil erosion and sedimentation in Cherag Veis watershed was assessed. To complete the study, the effects of suitable land use in diminishing these unwanted phenomena were also evaluated. The watershed is located south of Saghez City, enclosing an area of 163.69 km2. At first, the rate of specific erosion and sedimentation and erosion severity was determined using the EPM model in the GIS environment. Present land uses and the optimum ones that were determined by a systematic land use evaluation and planning method were used in the model. The study showed that by adopting appropriate watershed management practices and land use planning, the total erosion and sedimentation rate may be lowered to around 7133 ton per year in the watershed. 

Complex and variable nature of the river sediment yield caused many problems in prediction of the long-term sediment yield and input into the reservoirs .sediment rating curves generally used to estimate the suspended sediment load of the river and drainage basin. Since the regression equations of the sediment rating curves obtained by logarithmic retransformation and little independent variable include in this equation they also overestimate or underestimate the true load of the rivers. In this research in order to improve and develop sediment yield estimation methods the estimates of 10 kind of sediment rating curves were compared with actual loads of 5 stations in different climate zones of the country by using accuracy and precision index .the results show that in estimating long term mean load of the selected periods the Linear-MVUE sediment rating curve has relatively high accuracy and precision comparing other kinds of sediment rating curves. In average, the accuracy index of this method is about 1.23 that is reasonable among other methods. Since this kind of sediment, rating curve uses different data characteristics and information it could be recommend for application in sediment yield estimation within acceptable confidence limits.

Study of uncommon flood occurrence phenomenon and its devastating losses could have important role on water resource managements. Simulation of rainfall-runoff originating from rainfall and snow thawing could be used in estimation of flood intensity and volume. This is not doable without a knowledge of hydrological and runoff processes. Therefore, employing of indirect methods for estimating rainfall- runoff processes has gained many attentions. The aim of this research is the evaluation of a pseudo-two dimensional mathematical model to simulate the accuracy of hydrograph of watersheds. This model can produce geographical parameters of watersheds in GIS medium of each rainfall event. In this way topographical and hydrogeomorphological characteristics are defined as topographic indices within raster framework. Using pseudo-two dimensional algorithm of ADEQUATE the path of flow of each cell of DEM of watershed to outlet is calculated. The amount of distributed flow of each cell to neighboring cells, and finally the total volume of water allocated to each cell is also determined. The allocated water volume of cell under study reaches the outlet through known path, as diffusive wave. The model calculates the time of equilibrium and with this process, based on time-area method, a time map is prepared for all map cells of the watershed. Then isochrones are drawn and the area of flood hydrograph is simulated using the famous time-area method. The model output was compared with four recorded flood hydrographs of Amameh watershed. The results of simulation of the four rainfall-runoff events showed that the model has a high capability in flood discharge rate estimation. The high and significant correlations (r=0.98 to 0.99; p<0.001) between simulated and measured data were observed. No significant difference was found between measured and simulated data. In conclusion, this model could precisely predict rainfall-runoff events.

Gully erosion is one of the developed and extreme types of water erosion that indicates sever soil loss. Gully erosion is more important than other surface erosions in sediment yield view point so that create many difficulties. Gully erosion also extends in many parts of Iran and its study particularly in view point of sediment yield is therefore very important to be taken into account. The present study was taken place in Darehshahr city in Ilam province, Iran, in order to investigate the relationship between sediment yield from gully erosion and rainfall depth, intensities and duration. For this purpose, 18 axial, frontal and degitated gullies were precisely selected and their morphometric variations were surveyed at the beginning and end of 5 storm runoff events during November 2005 to January 2006.  The important affecting factors were then determined with the help of factor and regression analyses. The results of the study showed that rainfall duration, 10, 30 and 60 minutes intensities were important factors controlling sediment yield by gully erosion. The rainfall duration was then found as the best indicator for sediment yield based on discriminative analysis. A significant relationship was ultimately established between sediment yield and rainfall duration with respective determination coefficient and estimation error of 81 and 28%.

Because of many problems associated with traditional procedures for identifying sediment sources, fingerprinting techniques, based on physical, chemical and organic properties of sediment and source materials, are increasingly being used as a valuable and effective alternative approach to assembling such information. In this method, a suitable composite (set) of diagnostic properties and a multivariate mixing model are employed to estimate the relative contribution of sediment sources to sediments transported to basin outlet. In this study, using suitable composites of geochemical elements, radionuclides, organic Carbon, Nitrogen and Phosphorous, capable of discriminating subbasins of the study basin, and a multivariate mixing model were used to determine contributions of that subbasins to sediment yield. The suitable composite fingerprints (elements) were obtained using discriminant analysis. The study basin is known as Margan, located in Pouldasht district, Makoo Township, Western Azarbaijan province. This basin has six subbasins. The suitable composite fingerprints having capability to distinguish the above mentioned subbasins include: Tl and Ce for the subbasins of 1 and 2, W, V, and Pb for the subbasins of 3 and 4, and Ni, Mn and Ce for the subbasins of 5 and 6. Mean contributions from the subbasins of 1, 2, 3, 4, 5 and 6 were to be estimated as 89.14, 10.86, 20.86, 79.14, 67.10 and 32.90% respectively. Low mean absolute errors (less than 11%) show high degree of correspondence between measured and predicted properties. High model efficiencies (greater than 0.99) confirm the goodness of fit of the mixing models. Also it is argued that fingerprinting estimates for sediment sources are consistent with field observations. Then although a number of limitations must be recognized, the fingerprinting approach to source ascription has high efficiency to determine relative importance of sediment sources (subbasins) in the study basin.

The groynes are structures which used for protecting the outer part of the bend and river plan stabilization projects. One of the most important problems for designers is the estimation of the maximum local scour depth in the vicinity of groynes. Due to contraction of the flow area, the local velocity increased and the scouring around groynes will be developed. The litrature review reveals that most of studies have been conducted on the past are on the straight groynes and a little information exist on local scouring around L-head groynes. In this study, the maximum depth of scour around straight and L-head groynes was compared. Also the effect of angle of parallel wall on scouring was investigated and the optimal angle of parallel wall was determined .By using dimension analysis, the dimensionless parameters were obtained and a general relation was developed by applying regression analysis. The results show that the maximum depth of scour around L-head groynes with upstream parallel wall is less than straight groynes and the optimal angle (minimum scour depth) of parallel wall respect to perpendicular wall in L-head groynes is a=110o (in the downstream direction) and a=60°(in the upstream direction).