JWSS - Journal of Water and Soil Science

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Effects of the β-adrenergic agonist metaproterenol were studied daily gain, carcass composition and feed consumption of Varamini female lambs were studied. Thirty lambs were randomly assigned to a randomized complete block design with three groups (treatments) and two blocks (live weight). The ration was similar for all groups (ME: 2.6 MCal/kg, CP: 14.9%) and lambs were fed ad libitum. Metaproterenol was injected subcutaneously at 0 (control), 7 (low dose) and 14 (high dose) µg kg^-1 w⁷⁵. Lambs were weighed at 20-day intervals.

Mean daily weight gain and feed conversion ratio improved significantly by metaproterenol (P<0.05), but feed intake was not affected. Hot carcass weight, carcass weight minus fat-tail, dressing percentage and longissimus muscle characteristics were different among the three groups (P<0.01). Physically separated fat from several depots and fat-tail weight significantly reduced in the metaproterenol groups. Carcass fat content decreased but carcass protein content increased in metaproterenol treated lambs.

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This research was conducted in Kooshkak Farm Research Station of Shiraz University in 1997 and 1998 in order to determine crop coefficient and water requirements of rice, using lysimeter. The variety used was Champa-Kamfiroozi which is an early mature variety and is grown by most farmers in the area. Results showed that potential evapotranspiration varied from 3.76 to 9.34 mm/day. Penman FAO method was used in calculating reference evapotranspiration. Crop coefficient was 0.97 in the initial growth stage, 1.25 in the mid-season growth stage, and 1.09 at the time of harvest. Total crop evapotranspiration rates in 1996 and 1997 were 560 and 757 mm, respectively. Average deep percolation rates in the growing season was 3.4 and 3.5 mm/day in 1996 and 1997, respectively. Finally the total water requirements of rice in 1996 and 1997 were 1983 and 2361 mm, respectively.

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This study was conducted to analyze the correlation among grain yield, yield components, duration of vegetative and grain filling periods in twelve oat (Avena sativa L.) cultivars at the Research Farm of the College of Agriculture, Isfahan University of Technology, from 2001 to 2003. A randomized complete block design with three replications was used. The correlation coefficients among the grain yield/m², fertile tiller/m², grain number/panicle and the duration of grain filling period were positive and significant. Among yield components, the number of panicle/m² and the number of grain/panicle had the largest direct effects on grain yield (0.68 and 0.30, respectively). Furthermore, the duration of the grain filling period had the highest direct effect on the number of grain/panicle and the grain weight (0.82 and 0.80, respectively), which were greater than its correlations with the number of grain per panicle (0.42) and 1000-grain weight (0.35). However, its negative indirect effects through other traits reduced the correlation coefficients. The results of path analysis indicated that the number of panicle/m² and the number of grain/panicle had the largest direct effects on the grain yield. Considering the direct effects of grain filling duration on the number of grain/panicle and the 1000-grain weight, and also the fact that most of the dry matter in oat is produced in this period, it seems plausible to use these traits as a selection criterion in breeding programs for higher yields of cultivars of oat.

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Improvement of feed efficiency in dairy farming economically has a great importance. In this study, the genetic parameters of net energy efficiency and its relationships with milk yield, 3.2% fat corrected milk, body weight, gross income and income over feed costs were investigated, by the 2589 monthly records collected from the 723 lactating cows in the 3 herds. The different requirements of energy were estimated, by the National Research Council (NRC) models. A general linear model was employed for determining significant factors affecting each trait. The genetic parameters were estimated by a multivariate analysis with the derivative free approach of restricted maximum likelihood algorithm. The animal models contained the fixed effects of herd-year-season, parity number and stage of lactation, the regression coefficients of each trait on the dietary levels of rumen undegradable protein and metabolizable energy, and the random effects of animal additive genetic, permanent environment and residuals. The heritability of milk yield, 3.2 percent fat corrected milk, body weight, net energy efficiency, gross income and income over feed cost, were estimates 0.31, 0.32, 0.30, 0.34, 0.24 and 0.29 respectively. The results of this study indicated that the direct selection for net energy efficiency might genetically improve the feed efficiency. It also seems that the selection for fat corrected milk may be effective for the indirect improvement of feed efficiency and economic performance of dairy cows.

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This research was carried out to investigate the heterogeneity of milk yield variance components in different production levels of holstein cattles. The first lactation milk yield records of 95945 Holstein cattles, which had calved in 651 herds through years 1991 to 2000, were used in this research. Data was collected by the Animal Breeding Center of Iran and adjusted for two-time milking per day. Records were classified into three classes: low (less than 5275 kg), average (5275-6874 kg), and high (more than 6874 kg) based on the level of production. Variance components and genetic parameters were estimated using single and three-trait animal models for each class and three classes with Derivative Free Restricted Maximum Likelihood methods (DF-REML). Bartlett test showed significant differences for variance components between classes. Milk yield heritability was estimated as 0.205, 0.276, and 0.196 for low, average, and high class, respectively, in both single and three-trait analysis. The gentic correlation coefficient between classes ranged from 0.80 to 0.85, Phenotypic correlation coefficients between classes were low and ranged from 0.17 to 0.19. The highest rank correlation coefficient between estimated breeding value by single and three-trait model was obtained in average class. The average changes in the rank of common animals in the top 1% of cows were greather than the top 5% of bulls. Adjustment for heterogeneity of variance components suggested selecting more top cows from herds with high level of production.

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In this study external fat-tail dimensions (upper, middle and lower width, length, length of gap, depth and upper circumference) and fat-tail weights collected on 724 Lori-Bakhtiari sheep were used to study external fat-tail dimensions and their relationships with fat-tail weights. Sheep were 3 months to 6 years old and slaughtered at the industrial slaughter house of Joneghan in Chaharmohal and Bakhtiari province in 2003. The mean of fat-tail dimensions were estimated as 15.83, 23.85, 24.73, 26.52, 14.96, 14.12 and 52.59 cm for upper width, middle width, lower width, length, length of gap, depth and upper circumference, respectively. Fat-tail weight varied from 0.10 to 20.60 with overall mean of 2.71 kg. Fat-tail percentage varied from 1.18 to 37.18 with overall mean of 11.87 percent. The effects of fixed factors of age, sex and body condition of sheep on all of traits were highly significant (p<0.0001). The least square means of all traits except fat-tail percentage were increased with increasing age of sheep. Lowest least square mean (± s.e) of 2.12 ± 0.25 kg fat-tail weight and 7.91 ± 0.72% fat-tail were observed for sheep having body condition score of 1 and the highest least square mean with fat-tail weight of 9.84 ± 0.56 kg and fat-tail percentage of 20.59 ± 1.63 were observed for sheep having body condition score of 5. Estimation of correlation coefficients among external fat-tail dimensions and fat-tail weight were positive and varied from 0.60 between upper fat-tail width and fat-tail weight to 0.83 between upper circomference of fat-tail and fat-tail weight. Upper circumference of fat-tail accounted for %69.5 of variation of fat-tail weight. This study showed that fat-tail weight in live sheep of Lori-Bakhtiari could be estimated using external fat-tail dimensions with very high accuracy (r = 0.904).

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Genetic variation within and between five Iranian sheep populations including Sanjabi (SAN), Kordi Kordistan (KKO), Kordi Khorasan (KKH), Mehraban (MEH) and Moghani (MOG) was assessed using six microsatellite markers (McMA2, McMA26, MAF64, OarAE64, OarCP26 and OarFCB304). The PCR reactions were successfully perfomed with all primers except OarAE64. All locus-population combinations were at Hardy-Weinberg equilibrium except McMA2 in MOG population (P<0.005). Polymorphism criteria showed that the five studied loci were polymorphic in all populations. The lowest D_A genetic distance (0.234) was observed between KKH and KKO and the highest (0.388) between SAN and MOG populations. The dendrograms based on D_A distances were drawn using unweighted pair-group method using an arithmetic average (UPGMA) and neighbor-joining (NJ) method. KKO, KKH and SAN were grouped together at one cluster and MEH and MOG at another by both methods. The average expected heterozygosity for each populations (as interpopulation variation) ranged from 0.744 to 0.847 for KKH and MEH, respectively. The estimated time of divergence for two Kordi populations (KKO and KKH) was 445 years that complies with historical evidences. The findings of this research confirmed that microsatellite variation could be a useful tool for screening of investigating biodiversity among domestic animals.

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  Evaluation of genetic improvement of grain yield and other traits in cultivars released in different years is useful to determine plant breeding impact on grain yield improvement, to define future selection criteria and to identify the desirable environment and traits for further assessment. This study was conducted to evaluate the genetic improvement for grain yield and other traits of twelve oat (Avena sativa L.) cultivars released in Canada during 1921- 1997, at Research Farm, College of Agriculture, Isfahan University of Technology, during 2001-3 in a randomized complete block design with three replications. The regression of mean grain yield on released year of the cultivars showed that the rate of increase in grain yield during a 76-year period is 32.63 kg h^-1 year^-1 or 0.63% per year. Breeding programmes have inereased harvest index, grain number per panicle and fertile tillers /m². The effort of breeders in this period was to decrease plant height and days to heading. The other traits had small changes and showed no specific trends. In general the results of this study showed continous improvement of grain yield in this period. Genetic improvement of grain yield in evaluated cultivars closely correlated with harvest index. Therefore, most variation in grain yield of oats was due to variation in harvest index. Although much of the improvement in grain yield described here could be attributed to the increased harvest index, the scope for further improvement in this character may be limited. Further yield improvement of oats might be achieved by combining high biological yield with high harvest index.

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  Discharge routing as a mathematic process to forecast the changes of greatness, speed and form of flood wave is function of time in one or more points along drainage, canal or reservoir. Hydrologic and hydraulic methods are used to accomplish the flood routing. Although hydrologic method is less accurate than hydraulic methods but it is simpler to use in flood control and designing works with acceptable confidence. This study has been conducted for flood routing in Lighvan River from Lighvam hydrometric station to Hervy hydrometric station in eastern Azerbaijan Province in a distance the 12 Km. The discharge for different return periods (2, 10, 20, 50 and 100 years) was calculated by using upstream stations data. Then routing of every flood discharge was studied with different return periods by Muskingum and Muskingum-Cunge methods. Results showed significant difference between calculated discharges routing by two methods with discharge values to relate that return period in Hervy hydrometric station. The reasons of exist this different, is numerous for example mountain location this area and to exist sub drainage in between two stations and etc.

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Drought is a major factor limiting growth and development of crops such as mung bean (Vigna radiate (L.) wilczek) in arid and semi-arid regions of the world. This study was conducted to investigate the effects of different timing and severity of drought stress on physiological traits of mung bean and its relation to grain yield. A field experiment was carried out during 2004 growing season at Experimental Farm of Agriculture College, University of Tehran, Karaj, Iran. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Plants were exposed to moderate and severe water stresses at either vegetative (VS) or reproductive stages (RS). Physiological traits were measured at the end of vegetative and the middle of pod formation. Generally water stress reduced leaf net photosynthesis rate, stomatal conductance and leaf relative water content at different growth stages. The effects of RS treatments were more severe than that of VS one. Severe VS treatment increased photosynthetic water use efficiency, whereas RS treatments decreased it significantly. However, leaf area index and total dry matter were more responsive in VS compared to RS treatments. VS treatments did not affect harvest index, while RS treatments reduced it significantly. Drought stress also reduced grain yield by 9 and 49 % (relative to control plants) in severe VS and severe RS treatments, respectively. Therefore irrigation is critical during reproductive stage mainly because of the higher demand for photoassimilate. It is concluded that to maximize mung bean grain yield in arid and semi-arid areas, appropriate watering should be practiced across all phenological stages in general, and during reproductive stage in particular.

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The effects of irrigation, dry farming and drought treatments on the activities of antioxidant enzymes including superoxide dismutase, ascorbate peroxidase, catalase and peroxidase in barley leaves at different generative growth stages under field conditions were investigated. Three senescence parameters including chlorophyll, total soluble protein and rubisco large subunit protein loss, were also studied in order to compare our results to those reported by other researchers. The results showed that leaf relative water content (RWC), chlorophyll and total soluble protein and rubisco large subunit protein content declined with leaf age and the effect of water deficit. The activity of superoxide dismutase declined with the progress of the leaf age on all treatments but ascorbate peroxidase activity declined with leaf age only in irrigated (control) plants. There were no significant differences among developmental stages in catalase activity in control plants, while catalase activity declined in the water dry farming and drought stress conditions. Peroxidase activity increased with the progress of senescence for all of treatments in such conditions. Water deficit stress triggered increases in antioxidant enzymes activities. Results showed that among all studied enzymes, peroxidase has a key role in increasing resistance to oxidative stress on both the senescence stages and drought stress condition in Hordeum vulgare.

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One of our first activities in natural resources management and development programs is to acquire knowledge on Landslide Susceptible areas. The aim of this research is landslide hazard zonation in some part of Haraz watershed between Vana village and Emam zadeh Ali, using fuzzy membership functions and fuzzy operators. At first landslide points were recognized using arial photography and field studies. Afterwards, the inventory map of landslide was prepared. Then, each effective element in landslide such as: slope, aspect, elevation, lithology, landuse, distance of road, distance of drainage, distance of fault and precipitation map was prepared in GIS environment.These data were saved in raster and vector format in ILWIS software and used for analysis with theory of fuzzy sets. Fuzzy analysis was made by IDRISI software, after assigning value and fuzzy membership functions. In this research we used different fuzzy operators such as (And, Or, Sum, Product and Gamma). Results showed Gamma fuzzy operator had the best accuracy ( ) in making landslide susceptibility map in study area.

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In this work, a cabinet solar dryer for thin layer drying of Cuminum cyminum was evaluated in two conditions (Indirect and Mixed). Four levels of drying air flow rates (three active and one passive) were adopted. The experiments were performed in a completely randomized Block design pattern in three replications. Drying durations were kept constant (90 min) for all the experiments. Average initial moisture content of Cuminum cyminum was 43.5 %( db) and the product was set to be dried for 90min in the solar dryer (average 8%d.b). The effects of the drying air flow rates and modes of drying were highly significant in final moisture content of Cuminum cyminum. Duncan test was selected to evaluate the effects of different factors on average moisture content of the samples. The results showed that the passive air flow system in mixed mode drying conditions for drying the Cuminum cyminum was best. The drying duration for the mentioned condition was 55min to dry the product from 43.5% to 8 %( db). The experiments were conducted each sunny day of August-September 2007 from 11.30 till 13.The average solar irradiance was recorded 750 W/m2 average ambient air temperature was32°C and average ambient relative humidity was20%. Using the dryer in the best selected conditions reduced the moisture content of the product from 43.5% to 4.95% after 90 min.

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In order to study the effect of spur dike position in the bend on the process of scoring, some tests were done in a laboratory flume of Plax glass material with 180 deg bend and R/B=4/7. In this research, by setting an spur dike in the laboratory flume with positions of 30,60,90,120,150and 160 degrees, discharge rates of 20 ,24 and 28 Lit/s , and fixed depth of 13 cm, the process of scoring around spur dike in pure water was investigated. For flume bed, gravels of uniformly granulated sizes were used. The results showed that the maximum scoring in the length of river bend is obtained with increasing the rate and angle of position up to the angle of 60 deg, and then from position of 60 deg the rate of scoring decreases up to the position of 120 deg, and finally the increase in the position up to 160 deg results in the maximum scoring.

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An extensive data collection on precipitation and runoff is required for development and implementation of soil and water projects. The unit hydrograph (UH) is an appropriate base for deriving flood hydrographs and therefore provides comprehensive information for planners and managers. However, UH derivation is not easy job for whole watersheds. The development of UH by using easily accessible rainfall data is then necessary. Besides that, the validity evaluation of different statistical modeling methods in hydrology and UH development has been rarely taken into account. Towards the attempt, the present study was planned to compare the efficiency of different modeling procedures in hydrograph and 2-h representative UH relationship in Kasilian watershed with concentration time of some 10h. The study took place by using 23 storm events occurred during four seasons within 33 years and applying two and multivariable regression models and 36 variables. According to the results, the median of estimated errors in estimation of 2-h UH dependent variables for verification stage varied from 37 to 88%. The results verified the better performance of cubic and linear bivariate models and logarithm-transformed data in multivariable model as well. The efficiency of multivariable models decreased when they were subjected to principle component analysis. The performance of backward method was frequently proved for estimation of dependent variables based on evaluation criteria, whereas the forward was found to be more efficient for time-dependent factors estimation.

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The Clark method is one of the most applicable techniques for development of instantaneous unit hydrograph whose efficacy depends upon the accuracy in estimating storage coefficient. The present study was conducted in Kasilian watershed in Mazandaran Province to determine the efficiency of developed hydrograph using Clark's method and to compare the Muskingum storage coefficients obtained through graphical, Clark, Linsley, Mitchell, Johnstone-Cross and Eaton methods. To this aim, the time-area histogram of the study watershed was initially developed. The 3h-unit hydrograph was then derived using the data collected in Sangedeh climatological and Valikbon hydrometric stations. The efficiency of Clark’s instantaneous unit hydrograph developed based on 6 methods for calculation of Muskingum storage coefficient was ultimately compared with the observed average 3h-unit hydrograph of the study area. The results of the study revealed that the Clark’s instantaneous unit hydrograph obtained from graphical method for estimation of storage coefficient with estimation error of less than 33.33% and efficiency coefficient of 83% could suitably simulate different components of the observed average unit hydrograph for the study watershed.

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Drops are the most important and common hydraulic structures used as energy dissipators in irrigation networks and erodible waterways. Dissipation of energy occurs in two different ways. One portion belongs to the geometric form of the structure (briefly called loss due to structure), whereas the other occurs due to happening of hydraulic jump downstream of the structure. The dimensions of drop structure and downstream stilling basin can be optimized if geometric and hydraulic characteristics are recognized properly. In this research, the effects of drop geometry and hydraulic characteristics on the loss due to structure were investigated. At first, the effective dimensionless parameters were specified. 14 physical models of more common drops including straight, inclined and stepped drops were then built in 2 heights of 51.5 & 25.5 centimeters and 2 bed slopes of 26.6 & 33.7 degrees. The number of steps in stepped models was chosen equal to 3 and 7. With establishment of 90 flow rate, the energy losses were compared. The results showed that in the range of variable parameters, the straight drop has the maximum amount of energy dissipation.

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In this research, the effect of installing position of bridge pier on scouring depth was studied in a bend laboratory flume, which is made of Plexiglas with 180 bend and a relative radius of Rc/B=4.7. Tests were conducted using one pier 6 cm in diameter under four discharge conditions with constant depth of 12 cm and clear-water conditions. Flume bed was fully paved by uniform sand. It was found that maximum scouring depth occurred in bend when bridge pier was installed in the position of 60 degrees. Also, in all situations increased scouring depth occurred by increasing discharge.

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Organic acids can affect phosphorus (P) sorption. In order to evaluate the effect of citric acid and oxalic acid on phosphorus sorption characteristics in calcareous soils, five different soil samples (0-30 cm) were collected in West Azerbaijan province. Soil samples (2.5 g) were equilibrated with solutions of KH2PO4 containing 0 to 20 mg P l-1. Five mM organic acids were added to each tube and sorbed P was calculated. The sorption data were fitted to Langmuir, Freundlich and linear equations. The results showed phosphorus sorption data were well described by the Freundlich and linear equations. The average values of Kf (distribution coefficient), n and equilibrium buffering capacity (EBC) of linear equation in citric acid treatment were reduced to 29, 12 and 17 percent, respectively and for oxalic acid reduced to 43, 27 and 14 percent, respectively. Maximum sorption was reduced significantly by oxalic as compared to citric acid. Standard phosphorus requirement (SPR) was decreased by 57 % as a result of organic acids additions compared to control condition. It is concluded that organic acids additions to soils containing more calcium carbonate and high amount of clay can decrease P sorption.

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The aim of present research is landslide hazard zoning using Bayesian theory in a part of Golestan province. For this purpose, landslides inventory map was created by landslide locations of landslide database (392 landslide locations). Then, the maps of effective parameters in landslide such as slope degree, aspect, altitude, slope curvature, geology, land use, distance of drainage, distance of road, distance of fault, stream power index (SPI), sediment transport index (STI), and rainfall were prepared in GIS environment. Relationship between effective factors and landslide locations were considered using Bayesian probability theory. In the next step, parameters classes weights were found and the landslide susceptibility mapping was achieved by fourteen modeling approaches (using whole parameters and deleting parameters one by one). The verification results by ROC curve and 30% landslide locations showed that the Bayesian probability model has 71.37% accuracy for the second approach of modeling in the study area.