Journal of Agricultural Sciences and Natural Resources
Year:2007 | Volume:14 | Issue:4|Papers Count:24

In this paper, comparative advantage of main crops in Khorasan province in 2003-4 was calculated. Then, sensitivity analysis of exchange rate and prices for these crops were investigated. Needed data were collected from Agri-Jihad Ministry and some other statistical centers. DRC, SCB, NSP indices were used to evaluate comparative advantage. According to these results dry weath, irrigated barley, paddy, irrigated weath, dry lentil and dry pea were placed at the first to sixth order in Khorasan province. Also according to mentioned indices, red bean has no comparative advantage.

The studying and quantitative measurement of uneven aged forest structure, despite of the structural complexity, allowed us to report some of the most important structural features of the forest and by this way, we can use them for stand management. In order to overcome the structural complexity of the beech stands, the information of diameter and height of all trees were obtained in the study area situated in 16 hectares of shastkalateh forest located in the east of Hyrcanian forests. The results showed that alder and maple combined with beech can indicate the primary stages of succession and in this state, ironwood and persimmon trees are mostly found in the middlestory and understory. But at final stages of the succession, the beech trees become dominant and abundant in the overstory and hornbeam coming as second main species in the stand. The biodiversity index is difference between various stages of the beech succession while diversity and richness of wood species are reduced in final stages of beech stand succession. In this forest, trees diameter distributions are normal based on De Liocourt index. Reductions of the trees in the diameter classes are suitable which can be considered as a model to maintain the structure for marking and managing the stand.

This research was carried out to investigate the effects of tree age and height on chemical constituents of Populus deltoides wood. Five poplar trees were randomly cut down from Dr. Bahramnia forest located in Shastkolateh-Gorgan. Three sample disks were cut from trees at heights of 1.30, 11m and 16.50m. The specimens were taken from pith to bark and from bottom to top of tree stem to determine the chemical constituents such as extractives, lignin and ash content. The results indicated that hot water soluble extractives decreased by age from pith to bark and from bottom to top of the tree trunk. Sodium hydroxide soluble extractives followed the trends as hot water soluble extractives. The extractives soluble in alcohol-aceton decreased by age and height. The lignin content decreased from pith to bark and increased from bottom upwards. The ash content decreased by age and from bottom to top of tree stem. Results revealed that the chemical constituents influenced by tree age than height.

There is an abundance of literature on many aspects of soil salinity and sodicity, and the impact of increased salt and sodium on properties, behaviour, management and productivity of soils. Soil sodicity also increases the rate of crust formation and soil structure breakdown, which in turn lead to a reduction in infiltration rate, an increase in runoff, and eventually increase potential for soil erosion. However the impact of sodicity on erosion and soil erodibility and sediment transport has received less attention. The aim of this study was to investigate the effects of changing soil sodicity of three Australian soils on their erodibilities and erosion losses under simulated rainfall. Erosion measurements were carried out on the 1 x 6 m flume of Griffith University's large rainfall simulation facility (GUTSR), with saturating the soils by tapwater and sodic solution, on slops of 1, 3 and 5%, respectively. Statistically analysis was done for trend of variations using regression models. Sediment loss increased for both sodium-treated soils with the Redlands soil showing an eight-fold increase. Mean aggregate/particle size of the eroded sediment decreased with increased sodicity. High sodium concentration thus contributed to the weakening of soil aggregates and their dispersion under the raindrop impact. Electrical conductivity and salt concentration of the runoff decreased exponentially with time from sodium-treated soils.

Abbandansar peat from a natural water tank, 5 kilometers southwest of Sari city (the Mazandaran province) was used in this research. Four rates of peat (0, 25, 50 and 75 percentage volume) were mixed with a sandy clay loam soil and a sand soil and their effect and also the effect of mere peat (100 percent) on evaporation, temperature and mechanical resistance. Dry bulk density and water holding capacity at different pressure steps (0,0.1 and 15 bars) were also measured and compared statistically. Incorporating peat increased soil and sand water content at 0, 0.1 and 15 bars and also available water. Soil and sand temperatures were slightly increased and mechanical resistance decreased. Evaporation rates were increased for sand cultures and decreased for soil. The magnificent effect of this peat on improving mineral soil available water is ideal for mixtures used in specific plant growth media and nursery.

Abbandansar peat from a natural water tank, 5 kilometers southwest of Sari city (the Mazandaran province) was used in this research. Four rates of peat (0, 25, 50 and 75 percentage volume) were mixed with a sandy clay loam soil and a sand soil and their effect and also the effect of mere peat (100 percent) on growth indicator factors and concentration in plant tissues were compared in a completely randomized design with four replications in pots with tomato at vegetative, flowering and fruit set stages. Elements tested were N, P, K, Ca, Mg, Fe, Zn, Mn, Cu, Pb, Cd, Ni, Co and Cr. The growth indicator factors were fresh and dry weights, plant heights and root weights. The maximum dry weight was obtained with the 50 percent culture at flowering stage in soil mixtures and with 75 percent rate at flowering stage and fruit set in sand mixtures. Plant tissue zinc concentrations increased with increasing rates of peat in soil mixtures and copper decreased. Nitrogen, iron, lead and nickel were increased in sand mixtures. The quantity of available copper with this peat is not enough for a high yield in these mixtures and a greater yield could be expected with a foliar application of copper. For all treatments, with the first application of peat in this research, the levels of Ni, Pb, Cd, Co and Cr by plant analysis are lower than standard limits for plant and human toxicity. This peat is rich in plant available nitrogen, iron and is ideal for mixtures used in specific plant growth media and nursery with supplementary copper sprays applied.

This study was conducted to predict total N using auxiliary variable (organic matter) by kriging, co-kriging and kriging-regression techniques at the field scale in Sorkhankalateh district, Golestan province. Soil sampling performed on the nested-systematic pattern in 101 points in a plot with 100×180 m area, under the farmer's management. Through the laboratory analyses, total N and organic matter were measured for 70 and 101 soil samples, respectively. Geostatistical analyses were performed on original data and simple variograms and cross-variogram for two variables were calculated. After validation of models and development of a linear regression model between two variables, three mentioned methods were compared according to predict total N throughout the given field. The results of this study showed that kriging-regression method had the lowest ME and MSE and the most determination coefficient compared to the other methods, indicating that this technique was able to predict total-N more accurately using auxiliary variable (organic matter) data. On the other hand co-kriging has been produced more precise predictions compared to kriging due to using auxiliary variable. Overall results of this study revealed that among the studied methods, kriging-regression technique by using cheap- to- measure auxiliary variable like organic matter and less complexity in calculation suggested to evaluate spatial variability of total N in the study area for precise management.

Estimation of additive and dominance genetic variances is important in breeding for self-pollinated crops. Therefore, an experiment was conducted with six pure lines of winter wheat using diallel mating design. Grain yield, biomass, plant height, number of spiklet per plant, number of kernel per spiklet, date of maturity, number of tiller per unit area were measured, in which, significant differences was found among parents only for grain yield, biomass, plant height and date of maturity. The results were also showed a significant difference among crosses. Additive as well as non-additive effects were important in controlling the above mentioned characteristics. High contribution of additive effects in governing biomass and plant height, and dominant effects in controlling of yield per plant were observed. The highest heritability was belonging to plant height. The parents C-75-1 and C-75-4 were shown the highest general combining ability for yield components. Hence they have a good genetic potential to produce a high yielding progeny. Dominant and recessive allele frequencies were not in equilibrium with respect to traits studied. Frequencies of dominant alleles were more than recessives for most of the traits studied. The results showed that increasing grain yield, dry weight and plant height were mostly controlled by dominant alleles.

The main objective of this study was to develop a seedling emergence model for faba bean, including determination of cardinal temperatures, biological day's requirement for emergence and faba bean temperature response curve. To do this, four faba bean cultivars (Barakat, Saraziri, Eraghi, and Gavi) were sown at 11 sowing dates (every month) and the number of days from sowing to emergence were recorded. Beta, Segmented, Curvilinear, Quadratic and Dent-like models were applied to describe the relationship between emergence rate and temperature. Root Mean Square Error (RMSE), coefficient of determination (R2), linear regression coefficients (a,b) and correlation coefficient (r) were used to detect the perfect model. Results indicated that response of faba bean emergence to temperature is best described by segmented function. Cardinal temperatures Estimated by this model were 0.98oC to 1.61 oC for base temperature, 24.9oC to 28.82oC for optimum temperature and the value of 35 oC was assumed as ceiling temperature. Estimation of biological days requirement by segmented model showed a significant difference between cultivars; cv. The emergence of Gavi small seeds occurced 6.65 day with the highest emergence rate (0.09 d-1). Biological day's requirement for other cultivars ranged between 8.60 and 9.72 days. The quantitative information provided by this study can be used in prediction of emergence under diverse temperature conditions.

Beta 1, 3-glucanase gene derived from barley encodes an antifungal protein and hydrolyzes glucans which are major components of cell walls of many pathogenic fungi. This gene increases plants resistance against fungus infection. In order to transform beta 1, 3-glucanase gene into the cotton, at first a suitable gene cassette was designed by addition of the CaMV35S promoter and the Nos terminator to open reading frame of the glucanase gene in pCaMV vector. Subsequently the complete cassette of glucanase gene was subcloned into T-DNA region of binary vector pBI121 between nptII as a selective marker and Gus as a reporter gene. The pBI121-Glu recombinant plasmid was used for gene transformation via Agrobacterium into the cotton shoot apices. After isolation the cotton shoot apices and inoculation them by Agrobacterium solution, explants were transferred to selective medium containing kanamycin. The surviving and regenerated shoot apices in selective medium that were positive in histochemical assay for Gus gene expression were considered as putative transgenic plants. They should be cared to grow enough for carrying out further molecular analysis to confirm the integration and expression of the interest gene and transformation event.

In order to study drought stress and manure effects on cell membrane stability (integrity) and leaf chlorophyll content in L17 soybean line, a split plot design was conducted on the basis of complete randomized block design. Main plots were included drought levels as irrigation after 50, 100 and 150 mm evaporation of basin class A, and 0, 15, 30 and 45 t/ha manure were assigned to subplots. The results showed that, relative water content (RWC) was reduced with increasing drought stress. In manure treatments, the maximum RWC was obtained by using 45 t/ha. At the end of flowering stage cell membrane stability (CMS) was increased with drought stress and it was from %70.14 (favorable irrigation) to %76.22 (drought stress). Increasing the use of animal manure caused decreasing in CMS from %75.96 (without use of manure) to %68.55 (use of 45 t/ha). At the end of flowering stage the maximum concentration amount of a chlorophyll (53.40 mgg-1 fresh leaf) and b chlorophyll (42.12 mgg-1 fresh leaf) observed in the moderate water stress condition and follow it in highly stress and favorable irrigation. At the seed initiation formation stage, the effect of manure on chlorophyll concentration was not significant (p>0.05); the maximum concentration of a chlorophyll (79.31 mgg-1 fresh leaf) was in moderate stress. The highest concentration of chlorophyll a was produced in 30 t/ha animal manure. The concentration of chlorophyll b was not significant (p> 0.05) in both irrigation and animal manure treatments.

High seed cotton yield is ultimate objective of any crop-breeding program. In this study, some of quantitative and morphological traits of cotton were evaluated in 6×6 diallel analysis. Six parent with 15 crosses (totally 21 genotypes) were studied in randomized complete block design (RCBD) with three replications at salty farm at Bandar-torkaman city during 2005. Fifty agronomic traits, including yeild and some of the yeild components were evaluated. Variation among genotypes were signification for all traits (except for emergence, inter nod length, number and length of sympodial branches and number of fruiting plant in plot). Based on mean comparison Bulgar 539xN: 200 were superior, to other Diallel analysis is one of the most widely used techniques, which determine type of genetic variation in quantitative characters. Data were analyzed according to Griffing (1956) method 2, model 1 and Hayman’s graphical analysis. Diallel analysis showed both additive and non-additive genes effect for these traits. In general, genes additive effects revealed the effectiveness of selection for plant height, stem diameter, number and lengths of monopodial branches and dry and wet weight leaf. Non-additive effects were effective for boll weight and seed yeild. Finally, additive and non-additive effects together were effective for selection in segregating population for boll number and early. Graphical analysis results indication partial dominance for plant height and number of monopodial branches and complete dominance for dry of weight leaf and over dominance effect for other traits.

Twenty female Holstein calves with average 40.7±5.7 Kg body weight were randomly placed on treatments in individual boxes and fed 10% of birth weight colostrum and milk in the first two days and until 45 days old. Treatments include: 1) feeding high quality alfalfa and calf starter (Ad lib) from 7 days old (Control), 2) feeding high quality alfalfa and calf starter (Ad lib) from 30 days old (Treatment). Both groups of calves were weaned at 45 days old. Data were analyzed in a completely randomized design evaluating effects of two nutrition management in calf period on rumen fermentation parameters, blood metabolites, type and growth of Holstein female calves. Calves in treatment group tend to consume more concentrate after solid feeding in contrast to control but it decreased gradually include lesser alfalfa and total DMI, which was statistically significant at 90 days old (P<0.05). Results showed that there is no effect on body gain of calves before or after weaning or on body weight at sampling dates. Feed to gain ratio was not altered too. Sum of body weight gain at 15-day periods was not influenced by treatments. Treatment showed significant reduction at nutrients digestibility (DM, OM, CP, ADF and NDF) (P<0.01). Rumen fermentation parameters (pH and NH3) just at 30 days old were significantly different (P<0.01). Glucose, TP and BUN were not altered by treatments except glucose, which was significantly different at 80 days old. Body measurements include: body length, wither height, hip height, abdominal size, heart girth, metacarpus size, metatarsus size, pin width, hip width and pin to hook length were not altered by treatments at sampling dates. It can be concluded that milk-based diet up to 30 days old could improve feed to gain ratio but performance of calves was reduced and using this method at young calves rearing depends on more researches.

This experiment was conducted in a randomized complete block design and included 600 Ross broiler chicks (male and female) which were divided into four groups with five replicates. This experiment was conducted in two periods starter 0-21, and grower 22-42, days. All of the diets were  isocaloric and isonitrogenous. The birds were received 0, 800, 1000 and 1200 gr probiotic (bacillus subtilis and bacillus licheniformis)/ ton diets in the starter period, and 0, 320, 400 and 480 g probiotic/ton diets in the grower period, which were termed groups 1 to 4, respectively. Body weight gain at starter period was significantly affected by dietary treatments (P<0.05), but body weight gain at grower period was not affected by using probiotic supplement (P>0.05). At the end of trial, the group 4 had maximum weight gain. The feed intake and mortality were not affected by experimental diets (P>0.05). There was no significant difference between treatments for feed efficiency (P>0.05), but there was significant difference between mean of treatments that were derived from Duncan,s multiple range test (P<0.05).There were no significant difference between groups in dressing, breast meat and thigh percent, at the end of experiment (P>0.05). The first treatment had the highest abdominal fat (3.04 percent) and fourth treatment group  had the lowest abdominal fat (2.43 percent), but among them, there was no significant difference (P>0.05). There was no significant difference between treatments for plasma cholesterol (P>0.05), but significant difference between mean of treatments were derived from Duncan,s multiple range test (P<0.05).The blood hemoglobin content was not affected by experimental diets (P>0.05). The number of white blood cells were significantly affected by dietary treatments (P<0.05), the group4 had maximum number of white blood cells, and group1 had minimum number of white blood cells.

Bromus tomentellus Boiss. from Poaceae is an important species which is common various habitats and geographically distributed widely in Iran. Seed collected from different area of the country, were grown under greenhouse conditions and a through comparative study on the morphology, anatomy of the raised plants  conducted during all stages of vegetative and reproductive growth. Morphological study indicated significant intra-species variation in number, length and width of the leaf, number, length and width of spikelet, spikelet/ inflorescens, floret number and length and width in spikelet, length and width of inflorescens, length of culm and inflorescens/culm. Anatomical studies showed significant differences within species when comparing: lamina overall total shape, number of lamina vascular system, keel form, number of rows and types of stomata, density of trichomes and also presence of silica bodies in epidermal layer. Cluster analysis was performed based on the results obtained using UPGMA method and the relevant dendrogram was constructed. The dendrogram showed two main clusters and each cluster contained samples belong to the corresponding ecological areas. It was concluded that it is probably possible to identify different ecotypes of the species based on the geographical distribution.

UF white cheese was enrichment by addition of, 40, 60 and 80 ppm of two chemical forms of iron (FeCl3 and FeSO4.7H2O), into retentate. Chemical and sensory characteristics of products were compared with control cheese. Chemical properties such as fat content, dry matter, pH, acidity, moisture, and iron were determined in 1, 15, 30 and 60 days after production. Organoleptical properties involving flavor, color and texture was evaluated by 25 consumer sensory panelists. Iron concentrations had no obvious effect on chemical properties. Statistical results showed that addition of 40 ppm FeSO4.7H2O and 60 ppm of FeCl3 had no significant effect on flavor of products but in fortified samples cheese with 60 and 80 ppm FeSO4.7H2O significant differences was observed. There were no significant differences between samples color after 60 days. In addition, results showed that texture of fortified cheese using 60 and 80 ppm of FeSO4.7H2O had significant, but 40 and 60 ppm of FeCl3 had no significant difference. Finally, results indicated that fortification of UF white cheese with 60 ppm of FeCl3 or 40 ppm of FeSO4.7H2O had no effect on sensory characteristics of products.

The phenolic compounds of pomegranate seeds (ten varieties) were extracted by using acetone solvent and ultrasonic method for all cultivars. The concentrations of phenolic compounds in the extracts were determined according to the Folin-Ciocalteu method, and results were expressed as tannic acid equivalents per gram dry weight of sample (TAE/gdw). One cultivar with the highest amount of phenolic compound quantity (post sia variety) was selected and effect of its pomegranate seed extract (PSE) on stability of soybean oil was determined. PSE was effective in retarding oil deterioration at 60oC with an increase trend in activity when concentration ranged for 100-350 ppm. Peroxide and TBA value for 350 ppm levels of phenolic sample and control at twelve days was 60.69 meqO 2/1 Kg oil, 0.188 and 91 meqO 2/1 Kg oil, 0.36, respectively.

Geographical distribution, host plant range and prey species of Stethorus gilvifrons were studied in Khuzestan province during 1998-1999. Duration of different life stages and feeding rate of this species, using sugarcane mite (Oligonychus sacchari) as a prey, were also studied at two temperatures 26±1 and 36±1Co, 60±5% relative humidity and 16 hours of light under laboratory conditions. Only one species, Stethorus gilvifrons (Mulsant), was collected and identified from different crops and weeds of this region. Six species of spider mites (Tetranychus turkestani, Oligonychus sacchari, Oligonychus afrasiaticus, Eutetranychus orientalis, Eotetranychus hirsti and Eotetranychus pomi), were also collected as major preys of S. gilvifrons. Under laboratory conditions at 26±1 and 36±1 Co mean duration time took 14.6±0.48 and 10.57±0.19 days to develop from egg to adult respectively. At 26 Co, the longevity and feeding rate of female, reared on Oligonychus sacchari, were 59.8±5.9 (day) and 71.5±7.55 (adult mites per day), respectively, that were significantly higher than longevity (51.2±6.7) and feeding rate (52.2±5.52) of males.

In the regions where crop water requirements are provided by ground water, for taking moisture or water up to soil surface or root zone, pumping systems are usually used. If we could replace pumping systems with electrical current or electrical field intensity, we would suggest a new irrigation method which is the main purpose of this study. Electro osmosis phenomenon has different applications which one of them is irrigation. This experiment investigated the effect of different electrical field intensities on moving soil moisture using electro osmosis phenomenon. For this purpose an isolated non-conductive container was built in 1 meter depth and 0.06 m2 area and filled with uniform moisture soil. Ten centimeters of depth in lower part of soil were kept in saturated condition. A steel bar as positive pole in saturated part and a metal network as negative pole in 10 centimeters below the soil surface were placed. Therefore, the distance of electrodes or poles will be 70 centimeters. Moisture was transferred from anode part to cathode part when electrical field was conducted. The electrical field intensities applied in soil containers in 5 days’ was 0.0, 28.6, 57.1, 85.7 and 114.3 volt/meter. Transmitted moisture in field intensities mentioned were %21.50, %29.21, %31.34, %33.00 and %36.50, respectively. The results indicated that more electrical field intensity is more transmitted moisture in soil in defined time.

In hydraulic analysis of open compound cross sections, the calculation of the critical depth is very important. There are different methods for estimating the number and amount of critical depths such as unit cross section, the conventional method with separation of cross section, energy method, momentum method and weighted Froude Number method. In all these methods the momentum transfer effect resulting from occurrence of cross gradient of velocity between main cross section and flood plains are not considered. This phenomenon, which is described as interaction effect, is ambiguous and complicated and the results of the works of researchers have not ended to the introducing and proposing of a practical and comprehensive method for design and investigation about compound cross section yet. The conventional method calculates average velocities higher in main cross section and lower in flood plains than real values. In this paper, the corrected one-dimensional method for estimation of critical depth was introduced the interaction effect is considered. In this study, the average flow velocity in main cross section and flood plain and consequently partial and total discharge rates have been corrected using the coherence method. Results showed that the conventional method with separation of cross section gives higher critical depth and specific energy. This increase depends on geometry and hydraulic condition of flow, and varies from few millimeters in small scale laboratory to tens of centimeter in the rivers. The variation range in minimum specific energy is higher than in critical depth.

Deficiency of country-wide and accurate information on erosion in Iran considered being an obstacle in water projects. Lack of long time measurements of erosion, as well as insufficient researches in this field, limit the access to trustable data. In this condition, the amounts of eroded materials reached to the outlet of watersheds can represent the conditions of soil erosion in upstream areas. Method of measurement of daily suspended loads which is based on measuring suspended sediment concentration and flow discharge is a robust method but needs continuous daily measurements and therefore this is feasible only for major rivers. In this research, to determine the most appropriate method for estimating the suspended sediments in Ghazaghly gauge station which is located on Gorganrood river, 3595 data of flow discharge and corresponding sediment discharge, recorded during years of 1971-2003, were analyzed. By establishing correlation between flow and sediment discharge on the basis of five models: linear, multi linear, median of groups, seasonal, and monthly, the best model for prediction was selected. To achieve this, the mean of square error and also the regression coefficient, as statistical indices, were used. The results indicate that the median of group's model has the best performance amongst the models. Additionally, to compare the estimated sediments with observed data during one month observation period, the statistical index, relative mean of error, was applied. The results show that the median of group's model in comparison with the other tested models gives the minimum relative mean of error and therefore has the best ability to predict sediment transport. It is suggested, that represent the flow conditions more precisely, the data collection in the case of flood events is conducted within smaller time intervals. The poor performance of the linear model compared with the other stated models in estimating the sediment load, indicates that using of this model should be performed with caution in Ghazaghli river.