فهرست مطالب

  • Volume:2 Issue:2, 2015
  • تاریخ انتشار: 1394/02/05
  • تعداد عناوین: 4
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  • Purushottam Subedi*, Jiban Shrestha Pages 35-39
    The continuous usages of chemical fertilizers have harmful effects on soil organic matter reserves, soil health and environmental safety. The use of Bio-fertilizers like Azolla not only increases the rice productivity but also improves the long term soil fertility. Azolla is a fast growing aquatic pteridophyte which fixes atmospheric Nitrogen by forming a symbiotic association with the Blue-Green Algae, Anabaena azollae. Azolla is an efficient Nitrogen fixer. It is grown in lowland rice fields because flooded habitat is suitable for it. Under favorable field condition, it fixes atmospheric nitrogen at a rate exceeding that of the Legume-Rhizobium symbiotic relationship. It increases the rice yield equivalent to that produced by 30-60 kg N/ha. As green manure in water logged soil, it enhances the rapid mineralization of nitrogen. It reduces the NH3 volatilization losses through its influence on floodwater pH that leads to the conservation of urea-N in the system to improve the efficiency of N fertilizers. It significantly improves the physical and chemical properties of the soil including improvement in soil microbial activities. It helps in addition of Organic Matter and release of cations such as Magnesium, Calcium and Sodium. The total N, available P and exchangeable K in the soil and N-uptake by rice can be improved. Therefore, Azolla application is considered as a good practice for sustaining soil fertility and crop productivity irrespective of some limitations.
    Keywords: Azolla, Biofertilizer, Soil fertility, low land rice
  • Kazem Ghassemi, Golezani*, Shabnam Heydari, Sirous Hassannejad Pages 40-45
    A field experiment was conducted in 2014 to investigate the effects of different irrigation treatments (I1, I2, I3 and I4: irrigation after 60, 80, 100 and 120 mm evaporation from class A pan, respectively), cultivars (SC704, NS640 and DC303: late, mid and early maturing, respectively) and positions on ear (upper, lower and middle) on seed vigor of maize. The experiment was arranged as split-split plot based on RCB design with three replications. Irrigation treatments, cultivars and seed positions were considered as main, sub and sub-sub plots, respectively. Although, water limitation had no significant effect on seed weight, seeds produced under limited irrigation conditions showed low vigor as measured by electrical conductivity of seed leachates, germination rate and seedling dry weight. Seeds of SC704 germinated earlier and consequently produced larger seedlings in comparison with other cultivars. The higher seedling dry weight of the lower position seeds of ear was mainly the result of larger reserve accumulation and rapid germination. The advantage of the lower position seeds was more evident under severe water deficit. Thus, selection of the large and uniform seeds could be a simple way for improving seed and seedling vigor in maize cultivars.
    Keywords: Maize, Seed position, Seed vigor, Water tress
  • Kazem Ghassemi, Golezani*, Nasrin Raei, Yaegoob Raei Pages 46-50
    This research was conducted in 2014, to evaluate the effects of water deficit and nitrogen fertilizer on grain yield, oil and protein contents of maize (cv. double Cross 303). The experiment was arranged as split-plot based on Randomized Complete Block design (RCB) with three replications. Irrigation treatments (irrigation after 60, 90, 120 and 150 mm evaporation) and nitrogen levels (0, 46 and 92 kg N/ha) were located in the main and sub plots, respectively. Mean grain yield per unit area decreased with decreasing water availability, but it was improved with increasing nitrogen fertilizer. Grain oil percentage significantly decreased, but protein percentage slightly increased as a result of water deficit. In general, oil and protein yields significantly decreased under moderate and severe water stress, mainly because of decreasing grain yield under these conditions. Nitrogen application decreased oil percentage, but increased protein percentage significantly. Nevertheless, nitrogen fertilizer enhanced oil and protein yields per unit area, with no significant difference between nitrogen rates. These results were positively related with grain yield per unit area in maize.
    Keywords: Nitrogen fertilizer, Oil yield, Protein yield, Water deficit
  • Zohreh Poudineh*, Razeieh Amiri, Shahla Najafi, Noshin Mir Pages 51-56
    In this study, antioxidant and antibacterial activities of Prosopis farcta (Fabaceae) were investigated. The extracts were derived from seed and fruit pod parts by Ethanol, Methanol, Octanol and n-heptan solvents. High performance liquid chromatography analysis was used to measure antioxidant activities. Among the extracts, the seed Octanol extract (IC50=0.95 μg/ml) showed the best antioxidant activity. Antioxidant activities in various solvents showed different trends that may be as a result of differences in polarity and H-bonding ability of each solvent. The highest phenolic content of P. farcta was also obtained by the Octanol extraction in both seed and pod organs. Antibacterial properties of extracts were only recorded by methanol and ethanol extracts of the fruit pods which inhibited the growth of Staphylococcus and Escherichia coli. The results of the present work indicated that the selective extraction of Prosopis farcta by appropriate solvents could be very important to obtain bioactive fractions.
    Keywords: Antioxidants, Antibacterials, Extract Solvent, Prosopis Farcta, Total Phenolic Content