فهرست مطالب

Journal of Agricultural Science and Technology
Volume:12 Issue: 5, Sep 2010

  • Supplementary
  • تاریخ انتشار: 1389/07/15
  • تعداد عناوین: 12
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  • Gh. R. Peykani, M. Kavoosi Kelashemi, H. Shahbazi, A. H. Akrami Page 511
    Using productivity index for investigating a firms’ performance makes it possible to evaluate efficiency of the production system and cost at the same time. In this study the Total Factor Productivity (TFP) of several sugar cane varieties in Imam Khomeini Cultivation and Processing Center in Khuzestan Province is compared. Two hundred and forty eight farms are categorized on the basis of variety years old and then Tornqvist-Tiel Productivity Index is employed for calculating TFP for each sugar cane farm. The investigated sugar cane varieties include CP57-614, CP69-1062 and CP48-103. Results revealed that year long utilization system gained the lowest TFP among utilization systems in all the mentioned varieties. The most suitable utilization system according to the TFP index is biennial for CP57-614 variety, triennial for CP69-1062 and five years for the CP48-103 variety. Triennial CP57-614 variety has the most partial productivity in fertilizer. On the other hand, the six year long plant of the forgoing variety exhibits the largest partial productivity in water. The largest partial productivity in machinery is shown in biennial CP69-1062 variety. Among these varieties, triennial CP48-103 one has the largest partial productivity per unit area cultivation.
  • H. Salami, M. Rostami Page 523
    Two models are commonly made use to explain the behavior of insurance industries, namely: risk-pooling and the risk-absorbing models. Neither of the two models provides an acceptable definition of insurance output in the economies experiencing high inflation rate. To address the deficiencies of the present models, an alternative was proposed in the current study as based on the theory of index number. To verify the reliability of the suggested model, all the three models were tested using times series data from Agricultural Insurance Fund in Iran. The first two models failed to provide a meaningful indication of growth of Total Factor Productivity (TFP) in insurance Fund over the period of study while, results of the productivity estimation in the context of the proposed model show more consistence with reality and demonstrate an acceptable trend. Thus, the proposed model seems to have the merit of being considered as an alternative one in evaluating the productivity improvement in Agricultural Insurance Fund in Iran and as well in other developing countries experiencing high inflation rate.
  • S. A. Hosseini-Yekani, M. Zibaei, E. Allen Page 535
    The aim of this study is to explore the feasibility of setting up a Commodities Futures Market in Iran. Specifications for the margin requirements, daily price movement limits, the length of expiration intervals, tick sizes and contract size of various potential future contracts are hereby examined. Saffron, pistachio and rice emerge as the three suitable Iranian agricultural commodities. A new computational method of Value at Risk (VaR) optimization model, using a nonparametric sampling approach, is employed to determine the daily margin requirements and daily price fluctuation limits. Expiration intervals are determined by the simulated daily future price with a minimum of volatility. The daily risk free interest rate and the minimum daily average trading value of a participant in the Tehran Stock Exchange (TSE) are used as benchmarks to determine the minimum tick size and contract size for each commodity. These contract specifications are the initially suggested quantities for setting up an agricultural futures market in Iran.
  • S. Khodayari, Y. Fathipour, K. Kamali, B. Naseri Page 549
    Seasonal activity and spatial distribution of Eoteranychus frosti Mcgregor, Tydeus longisetosus (ElBagouy and Momen) and Zetzellia mali Ewing were studied during 9th July to 22th October 2006 in an unsprayed apple orchard, Maragheh region, Northwest of Iran. Also the density dependence interaction between preys and predator was assessed. To estimate the spatial distribution pattern of these species, data was analyzed through Iwao's patchiness regression, Taylor's power law, Morisita's coefficient, Lloyd's mean crowding and index of dispersion. Iwao’s patchiness regressions and Taylor’s power law showed a random and Morisita’s coefficient, Lloyd's mean crowding and index of dispersion revealed an aggregated distribution pattern for E. frosti, T. longisetosus and Z. mali. The results indicated that the peak density of E. frosti and T. longisetosus occurred in mid September and in late August (2.46 and 4.4 per leaf, respectively). Regarding their predator, the peak density (10.34) occurred in early July. The linear regression between prey and predator densities indicated a density independent predation by Z. mali.
  • R. Namdar, Gh. Pezeshki-Rad Page 559
    The purpose of this study was to determine students’ attitudes toward international agricultural issues. The population for the study consisted of agricultural extension students at Tehran and Shiraz Universities, Agriculture and Natural Resources Colleges’ (N= 170). A stratified random sampling technique was employed to select samples, (n= 120). The study was conducted during the fall 2007 using a descriptive, correlational design. Cronbach’s alpha, an internal consistency measure, was employed to estimate the reliability. The reliability for the instrument was found to be acceptable (Alpha= 0.89). Questionnsire was employed to assess the students’attitudes toward international agricultural issues. Results revealed that students had positive or “in agreement” attitudes toward international agricultural issues. They especially were of the belief that they should know more about agriculture and its important standing in the world economy. Moreover, students were “in agreement” concerning educational methods, which can help them learn international agricultural issues.
  • A. Zomorodian, M. Barati Page 569
    Outdoor experiments on a once-through single glazed solar air heater with perforated metal absorber plate were conducted to determine the practical effect of absorber plate porosity as well as suction air flow rate on the collector thermal efficiency and its total pressure drop. Three aluminum absorber plates were made perforated by drilling circular holes with different diameter/pitch ratios in square layout. A fan was employed at the top of the collector to suck ambient air from the bottom side through absorber plate perforations. The flow channel was designed such that uniform air flow over the entire absorber plate area could be achieved. Five levels of air mass flow rates (0.0065 to 0.0321 kg m-2 s-1) were adopted. Pressure drop across the apparatus was measured. The inlet air was preheated by short wavelength radiation absorbed by the cover as well as the long wavelength emission by the absorber prior to catching the heat from transpired absorber plate. A maximum thermal efficiency of 84% could be achieved for the most part of the porous absorber plate at the highest air mass flow rate. The collector with minimum porosity showed a maximum pressure drop. In some experiments, the glass cover was removed to determine the outdoor effect of glazing. Comparing the performance of the collector with and without glazing showed that the unglazed collector was about 25% less efficient than the glazed one at the same overall operating conditions. This reduction can be attributed to high top radiative and convective heat losses for the unglazed collector at the outdoor conditions. The pressure drop for the uncovered collector showed a lower magnitude in comparison to the covered one. The inlet air passes and heats up (21-59°C above the ambient) through the solar collector, therefore the fresh and clean hot air can be continuously supplied for many purposes such as solar drying system.
  • H. Mohamadi, M. Alizadeh Page 579
    The purpose of this survey was to evaluate natural occurrence and content of Aflatoxin M1 (AFM1) in dairy products marketed in Urmia (Iran). During September 2007, 40 samples of pasteurized milk, 40 samples of Ultra High Temperature Treated (UHT) milk, 40 samples of creamy cheese and 40 samples of Iranian Feta cheese were collected from different supermarkets in Urmia city. AFM1 contents were determined through competitive Enzyme Linked Imunosorbent Assay (ELISA) technique. All milk samples analyzed showed mean AFM1 concentrations lower than the permissible level of 50 ng L-1 (23.22±8.65, and 19.53±7.47 ng L-1 in pasteurized milk, and UHT milk, respectively). The mean levels of AFM1 contamination were 43.31±18.51 ng L-1 in Feta cheeses, 21.96±3.23 ng L-1 in creamy cheeses. The potential risk of human exposure to aflatoxin M1 via consumption of milk and milk products is well known. Therefore, dairy products must be evaluated for aflatoxin and kept apart from fungal contamination as much as possible.
  • C. Borchani, S. Besbes, Ch. Blecker, H. Attia Page 585
    Raw (intact) sesame seed showed a high content of oil, protein and ash: respectively, 52%, 24% and 5%. Studies were conducted on some quality characteristics of sesame and olive oils. The following values were obtained from raw sesame, sesame paste and olive oils, respectively: unsaponifiable matter 1.35, 1.46, and 1.50%; total phenols 14.21, 16.82, and 53.33 mg kg-1 oil; chlorophylls 0.04, 0.09 and 1.88 µg g-1; carotene 2.62, 3.66 and 19.10 µg g-1; refractive index 1.47, 1.47 and 1.47; saponification value 186.6, 185.75, and 97.94; iodine value 113.35, 91.34, and 81.23, acidity along with of 1.64, 1.10, and 1.12 mg KOH g-1 oil. Fatty acid profiles of raw sesame, sesame paste and olive oils showed a predominance of oleic acid (41.68%, 41.94%, and 52.14%, respectively) followed by linoleic-acid (38.29%, 37.48%, and 17.82%). Storage effect at 65°C of raw sesame, sesame paste and olive oils were later on studied. Results showed that the oxidative stability of raw sesame oil was higher than that of sesame paste oil. Due to its all favorable properties, sesame oil could be used in either food or cosmetic products.
  • R. Niazmand, A. Niazmand, M. Sarabi, N. Arabpourjani, A. Doaie Page 597
    Probiotic products highly affect the health of consumers by reducing the risk of heart attacks and improving the desirable microflora in the intestinal tract. In this study the effect of yogurt (500g/d for 3 wk) enriched with either Bifidobacterium bifidum or Lactobacillus acidophilus on the level of cholesterol, Low Density Lipoprotein (LDL) and High Density Lipoprotein (HDL) of serum and as well on the intestinal microflora were investigated in 24 healthy volunteers. Statistical analysis indicated that lower levels of cholesterol and HDL were found after consumption of either one of bio-yogurts as compared to the control states (P<0.05), whereas changes of LDL were not significant. Also, in comparison with control periods the results of microbial counts indicated that the number of fecal coliforms excreted during the consumption of either one of the yogurt types were not noticeable, while the number of Bifidobacterium bifidum and Lactobacillus acidophilus increased significantly (P<0.05).
  • A. Rajaei, M. Barzegar *, Z. Hamidi, M. A. Sahari Page 605

    Phenolic compounds, especially those of plant origin, constitute an essential part of the human diet, and are of considerable interest due to their antioxidant properties. In this study, Ultrasound-Assisted Extraction (UAE), Microwave-Assisted Extraction (MAE), as well as Maceration Extraction (ME) methods were applied for phenolic compounds’ extraction from pistachio green hull. Response surface methodology was employed to optimize the extraction conditions as regards the yield of the compounds. A Central Composite Design (CCD) was employed to investigate the effects of three independent variables, namely liquid-to-solid ratio (8-20 times), temperature (25-65 °C) and time (5-45 minutes) on the dependent variable (level of total phenolic compounds). The results indicated that within the same extraction time, the extraction yield through UAE was higher than those in ME and MAE methods. Correlation coefficients (R2) of the models for UAE, MAE and ME methods were 0.95, 0.96 and 0.94, respectively. The optimal conditions for extraction of phenolic compounds from pistachio green hull through ME, UAE, and MAE methods were 20(v/w), 65°C, 45 minutes; 20(v/w), 65°C, 25 minutes; and 20(v/w), 65°C, 45 minutes, respectively. Under optimized conditions the experimental values well agreed with the values predicted by the proposed models.

  • M. Thammawong, O. Arakawa Page 617
    The effects of ethylene and 1-methylcyclopropene (1-MCP) on sugar accumulation during storage of Malus domestica Borkh. cv. "Tsugaru" apples were evaluated. Fruit was harvested and treated with ethylene and 1-MCP at both immature and mature stages. The loss of starch content in immature "Tsugaru" fruit was observed in ethylene-treated fruit at days 7-10, and the total sugar content of all tissue zones only changed slightly following storage. The highest sugar content was of fructose, and the lowest was of sorbitol. The difference in sugar content between ethylene-treated and untreated fruit was observed only after four days of treatment. Other ripening aspects of the immature fruit, such as respiration rate and ethylene production, were not affected by ethylene and 1-MCP. In the mature fruit, the sugar content changed slightly between days 4-7 and then dropped on day 10. Ethylene treatment resulted in an increase in starch hydrolysis and also affected the ripening characteristics of the fruit. However, exogenous ethylene did not seem to induce sugar accumulation in mature "Tsugaru" fruit during storage. Therefore, this study indicates that the accumulation of sugars in the detached ‘Tsugaru’ fruit during storage seems to correlate differently with the ripening properties and starch hydrolysis, depending on fruit maturity at harvest and its storage duration.
  • J. A. Olfati, Gh. Peyvast, H. Shabani, Z. Nosrati-Rad Page 627
    Accurate and nondestructive methods to determine individual leaf areas of plants are useful tools in physiological and agronomic research. A determination of the individual leaf area (LA) of such species in Brassicaceae family as red cabbage (Brassica oleracea var. cappitata L. f. Rabra), cabbage (Brassica oleracea var. cappitata L. F. Alba) and broccoli (Brassica oleracea var. Italica L.) involves measurements of leaf parameters including leaf length (L) and width (W), or some combination of these parameters. This research was carried out during 2008 (on eight cabbage, six broccoli, and three red cabbage genotypes) under open field conditions, to see whether an equation could be developed to estimate leaf area of cabbage and broccoli across their genotypes. Regression analysis of LA vs. L and W revealed several equations that could be used for estimating the area of individual cabbage and broccoli leaves. A linear equation having W as the independent variable provided the most accurate estimate of red cabbage as well as ordinary cabbage LA. The linear equation (LA= a+b W2) exhibited a high accuracy and precision in estimating red cabbage and non-red cabbage LA. For broccoli a linear equation having LW as the independent variable provided the most accurate estimate of LA, but required twice the time needed for leaf area measurement.