Journal of Agricultural Sciences and Natural Resources
Year:2008 | Volume:15 | Issue:1 |Papers Count:26

Following a field reconnaissance, three elevation levels (1800, 2000 and 2200 meters above see level) were recognized to investigate natural regeneration quantity and quality of oak (Quercus brantii) stands at Hyanan forest in Ilam province. Forest inventory was done with stratification sampling methods choosing 2000 m2 plots to record forest stands and 400 m2 plots to record regeneration (five plots at each stratum). Variables in macro-plot were included tree diameter (DBH), total height, stem height, maximum and minimum diameter for all trees in the plot and quality of oak trees and tree species diversity. Also, number of seedling was counted in each micro-plot. Analysis of variance (ANOVA) and Duncan test were used statistically to compare the results among three elevation levels. The results indicate that the site of interest exhibits an uneven-aged stand structure. The forest site located on 1800 meters elevation exhibits the most suitable stands considering tree density, diameter structure, and tree quality. In respect to the average height of trees and regeneration rates, stands located in 2000 meters were significantly better than stands of two other elevation levels. Also, the highest rates of regeneration establishment have been subsequently observed under shade and shelter of: (A) trees and bush, (B) shrubs and big stones; and the lowest rates were established on open areas. The results suggest that the seedling need shade at the early stage of growth.

Cation exchange capacity is an important soil chemical property, but it’s measurement is time consuming and costly. Cation exchange capacity can be estimated from soil physico-chemical properties. 20 soil samples from Marvdasht and Fasa regions in Fars province were selected in this study, and the cation exchange capacity, clay, silt and sand percentages, soil specific surface area, soil organic mater content, bulk density and particle density of each soil sample were measured, and the mean geometric soil diameter of each soil sample calculated. Then, linear and power regression equations were used for estimating cation exchange capacity. The best estimate for cation exchange capacity obtained with sand percentage by linear regression, and means geometric soil diameter, clay percentage and silt percentage by power regression. Also, the results show, using soil specific surface area, soil organic mater content, bulk and particle densities were not appropriate for estimating cation exchange capacity.

Effects of four NaCl levels on root concentration of macro elements and sodium, in seedlings of five citrus rootstocks namely: Bakraei, Volkamer lemon, Sour orange, Sweet lime and Mexican lime, were studied in a glasshouse, using a factorial experiment in randomized completely design with four replications. One-year old seedlings of each rootstocks were grown in pots, containing native soil (pH=8.2) and irrigated with water supplemented with 0(control), 20, 40 and 60 mM NaCl. At the end of experiment, concentration of N, P, K, Ca, Mg and Na in roots were determined. The concentration of macro elements varied among rootstocks even in control plants (no salt). Salinity had different effects on root concentration of macro elements. Salinity increased N concentration in root of all rootstocks except in sour orange and increased the concentration of P in root of all rootstocks except in Mexican lime. K concentration was reduced in root of all rootstocks but had no effect in Sweet lime. Salinity increased the concentration of Mg and decreased concentration of Ca in root of all rootstocks except in Volkameriana. Under salinity treatments, Na concentration increased in root of all rootstocks but the rate of increasing in root of Bakraei and Volkameriana were greater than other rootstocks.

Sour cherry (Prunus cerasus L.) is one of the important fruit in temperate zone of Iran. Hard storability of the fruit limits fresh consumption and therefore the main portion of sour cherry used in processing industries. There are a few reports on the storage of sour cherry therefore the research was conducted to increase the storage periods of the fruit by the natural compound such as Clove and Black Zira essential oils and grape seed extract in two temperature regimes (10 and 25oC). The treatments were 500 and 1000ppm of each essential oils or grape seed extract as emulsion and essential oils fumigation as 1ml in each package with and without covered by plastic film. Before treatment, physical and biochemical properties such as fruit weight, TSS, pH and titrable acidity (TA) of the fruits were tested. After treatment, each package was considered at 48 hour intervals for weight loss, fruit quality, stem browning, fungal spoilage and fruit surface shriveling. At the end of the experiment TSS, TA, and pH of treated fruit juice also were analysed. Our results shown that sour cherry fruits had good condition in ambient temperature (25oC) and in refrigerator temperature (10oC) after 2 and 3 weeks respectively. Our data also shown that low temperature (10oC) especially in covered boxes with plastic film in comparison with open boxes had positive effects on storability of the fruits. All natural compounds had significant effects on the measured factors during the experiment. Clove and Black Zira essential oils (500ppm) had the best results in all measured factors. Fumigation methods because of the high concentration decrease fruit quality.

The objective of this study was to estimate maternal common environmental effects on (co) variances and genetic parameters of birth weight (BW), weaning weight (WW) and live weights in six months (SW) in two flocks of Baluchi lambs breed in Abbas-Abad sheep breeding station in Mashhad. Data were analyzed using two animal models without (model 1) and with (model 2) maternal common environmental effect. The proportions of maternal common environmental effect to phenotypic variance (t2) were estimated as 0.14, 0.068 and 0.099 for BW, WW and SW, respectively, in flock 1. The estimates for these traits were 0.246, 0.038 and 0.040 in flock 2. Including t2 in animal model reduced direct heritability of BW 12.2 and 7.7 percentages in flocks 1 and 2 respectively, but direct heritabilites of WW and SW did not changed. Effects of t2 on maternal heritabilities of all traits were negligible. The inclusion of t2 in model decreased maternal permanent environmental effect as the proportion of phenotypic variance (c2) from 0.104 to 076 for BW, from 0.073 to 0.060 for WW and from 0.056 to 0.043 for SW in flock 1. c2 were also decreased from 0.098 to 0.083, 0.082 to 0.080  and 0.034 to 0.031 for BW, WW, SW in flock 2, resp. Reductions of the residual variances for BW, WW and SW were 17.9, 6.8 and 7 percentages in flock1 and were 35.5, 9.3 and 4 percentages in flock2, resp. The results of current study showed that the effect of t2 on BW was higher than WW and SW. Effect of t2 on weight traits was also higher than c2 effect. Therefore, including t2 in animal models for weight traits especially at early ages is recommended.

An experiment was conducted to determine the optimum level of faba bean with and without enzyme in broiler ration. In current study, 480 male chicks of Ross 308 were fed for 42 days and their performances were analyzed in a completely randomized design. Totally 6 treatments with 4 replications of 20 chicks were compared. Treatments were 0, 10 and 20 percent faba bean with and without enzyme. The experiment consisted of starting (0-21 days) and growing (22-42 days) periods. Rations had the same metabolically energy and protein levels and other nutrients were based on NRC (1994) recommendations. The results indicated that weight gain of chicks fed 20 percent faba bean with enzyme were higher than other treatments. Although chicks received 0.05 percent enzyme, had significantly less weight gain (P<0.05), other treatments had no significant differences in weight gain (P>0.05). Chicks fed control and 20 percent faba bean with and without enzyme had the highest feed and protein consumption and the lowest consumptions were found in 0.05 percent enzyme. Adding enzyme to rations including faba bean were improved feed efficiency in whole period, but it was not significant. Although there was no significant differences in protein consumption ratio and valuable carcass percentage among treatments, abdominal fat, liver, gall blader and pancreas percentage were lower in treatments with enzyme.

To investigate the effects of different levels of calcium salt of long- chain fatty acids (Ca-LCFA) and canola meal nutrition on nutritional digestibility and blood metabolites of dairy cows this study has been carried out using change over design (with a 2*2 factorial design) including 4 ration diet, 4 period and each period was 21 days with 8 dairy cow after calving. Treatment were 1) 15% cottonseed meal and 3% Ca- LCFA 2) 15% cottonseed meal and 6% Ca- LCFA 3) 15% canola meal and 3% Ca- LCFA 4) 15% canola meal and 6% Ca- LCFA. Results of experiment showed Concentration of Ca, TG, and Glocose of blood were not changed by feeding 15% canola meal vs cottonseed meal (p>0.05). Canola meal decreased blood Urea nitrogen concentration (16.23 vs 18.3) (p<0.05). Digestibility of DM, CP, CF were not affected (p>0.05), but digestibility of ADF decreased by feeding canola meal (50.75 vs 32.96) (p<0.05). Ca, TG, Glocose and blood Urea Concentration were not affected by feeding 6% Ca- LCFA (p>0.05). Digestibility of ADF, CP, EE significantly decreased when cow fed with 6% Ca- LCFA (p<0.05).  As a result, ration with 3% Ca-LCFA with canola meal replacing cottonseed meal in dairy cow ration are suggested.

Ascochyta blight caused by Ascochyta rabiei (Pass.) Labrousse is a devastaining disease of chick-pea (Cicer arietinum). Fifty-six isolates of Ascochyta rabiei on chick-pea collected fonm Kermanshah, Hamedan, Lorestan, Kordestan, East Azerbaijan and West Azerbaijan provinces were studied. This isolates were collected from infected chick-pea plants showing the Ascochyta blight symptoms. CTAB method used for genomic DNA extraction from fungal mycelium. Random Amplified Polymorphic DNA/ RAPD studied by 12 random primers. Cluster analysis for PCR products of four primers (Ar173, ArPU1, Ar082 and Ar171) performed by UPGMA (Unweighted pair grouped method by arithmatic average) method. Results showed that these isolates because of different patterns of DNA polymorphism were categorized into seven groups with in 75% similarity levels. We recommend that if the polymorphism of the isolates bands were standardized by migration of marker bands, RAPD technique not only could separate the isolates in multiple groups but also is an effective, rapid, reliable technique to study genetic variability between fungal isolates. Other hand standardization polymorphic bands were used in the similar molecular techniques.

Effects of fortification of Setareh flour with iron, folic acid, zinc and calcium on chemical properties (dry gluten, wet gluten, gluten index, protein and zeleny value), organoleptic properties (form, up surface, down surface, tenderness, masticationability, softness, odour and flavour) and shelf life properties (by considering bread staling after 24, 48 and 72 hours at room temperature) were considered in Barbary breads and compared with control treatment.  In this study we have 4 treatments as follows: 1- Setareh pure flour without any fortificant/ as control, 2- Flour fortified with low dosage of fortificants: (ferrous sulfate 20, folic acid 1.5, zinc oxide 20 and calcium carbonate 900 p.p.m), 3- Flour fortified with middle dosage of fortificants: (ferrous sulfate 30, folic acid 2, zinc oxide 30 and calcium carbonate 1200 p.p.m), 4- Flour fortified with high dosage of fortificants: (ferrous sulfate 40, folic acid 2.5, zinc oxide 40 and calcium carbonate 1500 p.p.m). Statistical data have shown that, in all mentioned properties flour treatments fortified with minimum and middle amounts of fortificants had better results than the flour fortified with maximum amounts of fortificants. Minimum and middle treatments didn’t have any significant differences, so with due attention to international organizations (WHO, FAO) and provide vital micronutrients for body, we propose middle treatment.

Aflatoxins are the toxic secondary metabolites produced by Aspergillus flavus and related fungi in foods such as groundnut. They are carcinogenic, mutagenic, teratogenic and immunosuppressive agents that cause adverse affects on human and animal health. In this study 156 groundnut samples collected from markets in Northern provinces of Iran (Gilan, Mazandran and Golestan) were examined for aflatoxin B1 concentration (mg/kg) by indirect competitive enzyme-linked immunosorbent assay (ELISA), and A. flavus seed infection in groundnuts was determined by blotter plate method. This revealed A. flavus seed infection in 58.23%, 46.67% and 36.9% of groundnut samples collected from Golestan, Mazandran and Gilan, respectively, with the percent seed infection between 8 and 100%. Only one sample conatined 491 mg/kg of aflatoxin and in the remaining samples the toxin concentration was within the acceptable limit of 5mg/kg. There was no significant variation in toxin concenration (P>0.05) between groundnut samples collected from different provinces. There was no significant difference in A. flavus seed infection in samples from Golestan and Mazandran (P>0.05), but there was significant difference in samples from Gilan with samples from Golestan and Mazandran (P<0.05). This study revealed high A. flavus seed infection in groundnut samples from markets, but aflatoxin concentration was within the limits in most of the samples probaly due to unfavorable conditions for toxin production. However, seed predisposed to A. flavus poses potential risk for high aflatoxin contamination under congenial storage conditions.

Melon, cucumber, muskmelon, squash and watermelon are an important vegetable crop in Iran and cucurbit viral diseases are the most limiting factors of these crops for growers. Cucurbit cultivars grown in the fields and greenhouses of different regions of Iran were surveyed for infection of Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus-2 (WMV-2), Cucumber mosaic virus (CMV), Tomato spotted wilt virus (TSWV), and Squash mosaic virus (SQMV) and Papaya ring spot virus W (PRSV-W). A total of 1230 samples, representing three watermelon, six melon, one cucumber, twelve muskmelon and two squash cultivars in the fields and 2389 samples, representing sixteen cucumber, one watermelon and three muskmelon cultivars in the greenhouses were tested by indirect and /or DAS-ELISA tests. With the exception of ZYMV, all viruses were detected in watermelon (Citrullus vulgaris L.) cv. Charleston Gray. All melon cultivars were found to be infected at least to one of six viruses. The results indicated that melon (Cucumis melo L.) cv. Ghasri is only resistant cultivar to six viruses. In contrast, melon (Cucumis melo L.) cv. Mashadi was susceptible to all six mentioned viruses. All sixteen cucumber cultivars grown in greenhouses were found to be infected at least to one of the six viruses. These results indicated that susceptibility of cucurbit cultivars to viral infection is considerably different.

Potato spindle tuber disease is one of the important diseases of potato. This viroid is an economically important pathogen especially in potato seed exporting countries, where they must produce certified and free PSTVd seeds. For detection of Potato spindle tuber viroid in summer and fall of 2004, a survey in farms of Razavi and Northern Khorasan provinces was carried out and 250 tubers were collected that showing spindle shape and malformation symptoms. Samples were stored in cold room at 4oC. The tubers were planted under greenhouse condition after passing their dormancy period and starting germination. The leaves of these potatoes were used for RNA extraction by PEG6000 precipitation method. After extraction, these RNA were loaded on the Denaturing Polyacrylamide Gel Electrophoresis at 60oC, and then stained by silver-staining manner. Specific viroid band in comparison with positive control was seen. In another procedure, viroid band has been revealed after loading RNA on Return Polyacrylamide Gel Electrophoresis at two temperatures, 15oC and 40oC, following silver staining procedure. The extracted RNA viroid was inoculated on healthy potatoes (Agria cultivar) and tomatoes (Mobile cultivar) in greenhouse. Infection of inoculated plants has been confirmed by Return Polyacrylamide Gel Electrophoresis test as well. The symptoms mentioned above appeared on these plants after inoculation. This is the first report of PSTVd in Razavi and Northern Khorasan Provinces.

This investigation has been done with the objective of under standing the effects of Halloxylon plantation on plant diversity and homogeneity of understorey vegetation and comparison of diversity indicators. Three different site of 10-15 year, up to 25 year age and non- planted as a reference selected for comparison. Then the samplings by random- systematic method have been done. Data analyses were done by comparison of average values and LSD experiment. The study conducted that the maximum plant diversity were in the site of up to 15 year age and the minimum diversity occurs in the reference site. The maximum increasing rate of diversity occurs in the first years of growing. Among the diversity indicators the Hill index is more preferable, and among the homogeneity indicators the Simpsone index was applicable.

The effects of geologic, topographic, climatic and biotic factors appear in soil properties through time. So, soil properties are one of the important factors that influence distribution of vegetation especially in saline area. The aim of this research is to investigate the relationships between soil characteristics and vegetation distribution in order to determine the most important factors affecting on distribution and establishment of plant species. The study area in Gherkhelar rangelands is located in Marand of eastern Azarbayjan province. According to the distribution of vegetation cover and based on field surveys, plant communities were distinguished. To assessed vegetation in each plant community, ten transects with 50 m length and 100 m intervals were established. Within each transect, canopy cover, as well as density of species was measured using of point-quadrate method. In each community, profiles were dug and soil was sampled in depths of 0-20, 20-40, 40-60 cm. The soil samples was analyzed for physical and chemical characteristics such as: soil texture, Ec, pH, Na, Mg+Ca, ESP and PSW. Multivariate analysis and Canonical Correspondence Analysis (CCA) was applied to determine relationships between soil and vegetation data using CANOCO soft wares. Results show specific relationship between soil characteristics and vegetation. Results of CCA showed that the effect of deferent soil parameters on plant species is not the same and the most important factors affecting on distribution and establishment of plant species in study area were Ec, Na, and PSW.

To determine and compare some physical properties of Berhi and Khasoei varieties of date fruits, physical properties experiments of date fruits were carried out at moisture contents of 31.02% and 30.59% (d.b.) for Khasoei and Berhi, respectively. Results show that the average mass and volume of Berhi; 5.97g and 5.90g/cm3 have significant differences with respect to Khasoei variety which were as 3.78g and 3.56g/cm3, respectively. Dimensions, geometric mean diameter, volume, projected areas, surface area and porosity of Berhi was larger than Khasoei with a significant difference, while density and bulk density of Khasoei were larger than Berhi. The sphericity of both varieties was 0.77. Variance analysis by completely randomized design showed that the coefficient of static friction has only a significant differences respect to the kind of variety. Result of this paper is useful in design of post harvest equipment of date fruit.

Phosphorus fertilizer application rate is high in Qazvin province’s corn cultivation, regarding its calceous soil and high need of corn to this nutrient. On the other hand, the P fertilizer application and distribution should be carried out carefully as this macronutrient is low-mobile and fast – fixing in the soil. In this experiment, after primary soil preparation and sampling, two seed sowing methods using a row-phosphorus planter (capable to insert fertilizer beneah the seed) and a common corn seed row planter (top-dressing fertilization) were compared to each other. The experiment layout was factorial based on complete randomized block design (CRBD) with four treatments and three replications. Seed corn cultivar “SC 704” was used as experimental material. The experiment was performed at Qazvin’s Feyz-Abad Research Station, Qazvin, Iran, for two years. Treatments included 1) common sowing method accompanying with top-dressing fertilization 2) sowing, using a drilled-fertilizing machine with its fertilizer insertion into the soil. In this treatment, triple super-phosphate was used in three rates: according to recommendation, %25 lower than recommendation, %50 lower than recommendation. The fertilizer was inserted in the depth of 5 cm beneath the seed. Yield, stem height, 1000-seed weight, ear length and diameter, leaf P and Fe and Zn concentrations, seed number per ear and seed number in ear circumference were measured. According to results; yield increased in a %15-27 rates in seed-beneath fertilization, in all three fertilization levels. On the other hands, %25-%50 decrease in fertilization rate did not affect or decrease yield significantly (a=1%). No significant difference was recorded in other measurements.

Because of economic and simplicity in construction, trapezoidal broad crested weirs are widely used in water conveyance systems and as flow measuring or water level controlling devices. Due to extensive usage of broad crested weirs, the optimum cross section dimensions can lead to economic design. Looking on literature shows no significant work have been done to investigate the flow characteristics on optimum size of cross section of trapezoidal broad crested weirs on different soils. Thus, in this paper at the first, the optimum size of weir cross section was determined by genetic algorithm approach and then the experimental studies on six optimal models have been carried out and the weir discharge coefficients were obtained. Based on the momentum equation and using experimental results a semi-analytical equation to predict the weir discharge coefficient is presented. The results demonstrated capability of intelligent approaches for obtaining the optimum structure and presentation of a convenience method to predict the discharge coefficient of trapezoidal broad-crested weirs. The results also show that the sloping of upstream face of broad crested weirs cause to increasing the discharge coefficient by 4 percent.

Gabion weirs and specially stepped gabion spillways are structurally stable and efficient energy dissipaters with a wide application in hydraulic engineering. Since flow equations in porous media such as stones are difficult to solve, estimation of energy dissipation and structure behavior as a function of effective parameters using physical models seems rational. Energy dissipation with stepped gabion spillways is a function of up and down slope inclinations, porosity and drop number (as a function of flow). A change in porosity affects the ratio of inflow to over-flow, affecting energy loss. A considerable reduction in energy loss ratio was observed with increasing porosity, above 38 percent specially, using twelve physical models with two parameters, including four porosities (30, 34, 38 and 42 percent) and three inclinations. The inflow to overflow ratio is increased with increasing porosity, indicating the energy loss with flow over the steps is greater relative to friction with stones, contrary to a reduction in inflow friction loss with the increasing porosity.  With 1:1, 1:2 and 1:3 Weirs down slope inclinations and different inflow rates from 10~40 lit/s, four equations were obtained for the combined effect of all parameters on the ratio of energy loss using SPSS and SAS soft wares in this research. The results indicate that the porosity is more efficient than downstairs slope on energy dissipation. With decreasing the porosity, the energy loss increase and from porosity=38%, the energy loss increase much more.

The side weir is a hydraulic structure which is widely used in irrigation and drainage networks and water treatment plants. The discharge over the side weir is a spatially varied flow condition with flow reduction. In this study, the effect height and width of the side weir on the variation of spatial discharge coefficient is investigated in sub-critical flow condition and in a rectangular flume. From the result, it was found that with downstream flow control, the variation of the discharge coefficient along the side weir is a function of the ratio of flow depth over side weir crest at the end of weir to weir length and ratio of distance from the upstream of the weir to weir length. Also, it was found that without downstream flow control, the variation of discharge coefficient is a function of the ratio of weir width to flow depth at the end of the weir, ratio of weir height to flow depth at the upstream of the weir and ratio of distance from the upstream of the weir to flow depth at the end of side weir. Additionally, a statistical model is proposed to estimate the spatial discharge coefficient in sub-critical flow condition. The proposed model is compared with the previously published data and produced reasonable results. There was a good agreement with a relative error of less than ten percent. Finally, the above model enables to estimate relatively accurate results when compared with the overall discharge coefficient models.

Drip irrigation system is the efficient method of vegetable crop irrigation. This investigation is made to study water distribution horizontally and vertically in the root zone of radish crop. This study is also about leaching water below the root zone with using the modeling approach in the crop root zone. In this research laboratory and field data are used by HYDRUS-2D model. It is a high capability simulation model. Results of modeling indicated that with choice of suitable irrigation cycle (48 hour here) and emitter discharge, soil moisture is maintained at field capacity level during the whole cropping season and it decreases very slowly and supplies the required moisture for the crop. The results of water leaching and infiltration showed that leaching water below the root zone from drainage boundary compared to the total volume of water applied for the whole growing season is very low. Volume of drainage water is 0.05% of the total water used which is negligible.

More than 80% of drinking water of Gorgan city is supplied by groundwater of the region (Ziarat, Garmabdasht, and Shast-kula aquifers) and rest of that from Ziarat and Alang Dareh rivers. Hydro chemical studies and interpretations carried out on collected samples on Piper, Durve, and Gibbs diagrams in summer and winter 1383. The results indicate that hydro chemical fancies of drinking water are Ca+2-Mg+2 HCO-3 Cl- and Ca+2-Mg+2 HCO-3. According to hardness classification, water class of Gorgan drinking water is in the range of very hard. While, the total dissolved solid (TDS) of Gorgan drinking water is rock-dominance according to Gibbs classification. The data obtained from TDI and SI diagrams shows that the rate of ionic concentrations are increasing in flow direction of groundwater, but not for wells located in the northern part of the city. The saturation index variation on TDI and SI diagrams is not continuous. So, it could be concluded that Khazar fault causes high changes in ionic concentration and saturation index of groundwater in northern region of city. According to interpretation of laboratory chemical data analysis, the precise knowledge of chemical quality of drinking water resources could be useful in planning and management of drinking water resources in this city.

Heterotrophic seedling growth has described as the product of the following two components: (1) the weight of mobilized seed reserves and (2) the conversion efficiency of mobilized seed reserves to seedling tissue. This research was carried out to evaluate germination and seedling growth of aged seeds of wheat (cv. Zagros). Seed deterioration treatments were 0, 6, 12, 18, 24 and 30 days at 40oC. After that seed deterioration was carried out, one experiment on seedling growth and two experiments on germination were conducted. Results indicated that seed deterioration treatments, resulted in decreasing of germination rate and increasing of time to beginning and time to 90% of germination, significantly. Also, significantly seedling dry weight decreased linearly with 0.035 mg/day when exposed to 40oC. Study of two components related to the seedling heterotrophic growth revealed that seed reserves utilization decreased significantly, while conversion efficiency of mobilized seed reserves did not affect significantly.