Environmental Sciences
Year:2006 | Volume:4 | Issue:13|Papers Count:8

In this research entitled noise standards for passenger cars in Iran, in order to identity the permissible levels of sound for passing-by noise and the noise from vehicle exhausts and horns, through a step processing method, at first the real current situation of vehicles was obtained through different tests carried out on 100 vehicles of different types. The results have been analyzed statistically using the ATATGRAPHICS PLUS Version 2.1 software. The second step has been the study of other countries' standards and regulations as well as the European Commission Directives 70/15/EEC and 70/388/EEC which have formed the basis of this study.According to the test results analysed and the Directives mentioned above, the permissible sound levels that have been identified are as follows: 77 dB (A) for passing-by noise of the Ml class; 80 dB (A) for the NI class; 86 dB (A) for exhaust noise and 87 dB (A) TO 112 dB (A) for horn noise for all types of vehicle.

The Purpose of conduc6ng this study was to develop appropriate strategies for the co-management of natural resources in Razavar sub-basin which is an important part of the karkheh watershed. To this end, 1ield force analysis was used as a theoretical framework and tested by a participatory appraisal of natural resource methodology. In this research surveying, problem solving, ranking and mapping, brainstorming and discussion group techniques were all used Results showed that the most important problems were flood, deforestation, overgrazing, drought and the transfer of grassland to agrictiltural fields. The best solutions to confront these problems were identi1ied as including: strengthening the watershed cooperative society, establishing conflict solution consultation in the local community to prevent the destruction of natural resources within the framework of an 'integrated' approach towards the natural resource management for Razavar sub-basin.

The effect of green manure and crop residue (summer cover crop) on supplying nitrogen and the weed population in garlic (Allium Sativum) organic farming was the subject of this study. In a one-year experimental design, the accumulation of dry matter and nitrogen in clover (Trifolium alexandrium), Vicia (Vicica sativa) and bean (Phaseolus vulgaris) were studied as summer planting. The tuber yield of garlic cultivated following these vover crops was compared with 0, 80 and 120 Kg N ha-1 of urea. In addition, the effect of mulch from cover crops on weed biomass was evaluated. The greatest tuber yield was obtained from the 120 Kg N ha-1 treatment. In spite of lower nitrogen uptake in the clover treatment, the economic yield of garlic had not significantly differed. In vicia, bean and clover, the tuber yields were 7.500, 6.870, and 8.660 Kg ha-1 respectively. The amount of nitrogen accumulation in clover, vicia and bean was 67.8, 40.5 and 36 Kg ha-1 respectively. Due to greater residue, clover reduced weed biomass by 43%, 39% and 31% in comparison with 120, 80 and 0 Kg N ha-1 respectively. Bean and vicia, due to their lower residue production, had a smaller effect on weed growth in comparison with clover.

Crude oil is one of the most important pollutants of the soil in the southern part of Iran. Crude oil can leak into the soil during extraction purification or transportation. The soil contamination could damage the organisms of the soil, including plants and microorganisms. Some plants and microorganisms are able to degrade the oil in the soil.Two types of plants including legumes and grasses have higher potential to be used for phytoremediation. In the present study, the effect of mixed plant, alfalfa (Medicago saliva) and fescue (Festuca arundinacea), on phytoremediation of different concentrations of light crude oil (0-10%) in soil during 120 days was studied. Total bacterial count was higher in a vegetated sample with 7% crude oil. The oil I degrading bacteria was higher than non-vegetated samples.In vegetated samples, the higher crude oil reduction was observed in sample with I% crude oil (36.7), while the lower reduction was observed in sample with 10% crude oil (5.6). The total biomass was higher in control sample (9.6g), while it was lower in 10% sample (0.24 g). Our results showed that phytoremediation with mixed plants were not efficient in contaminated soil with more than 5% crude oil.

The obligate phytoparasitic fungi of the orders Uredinales (Rust fungi); Ustilaginales s.lat. (Smut fungi) and Erysiphales (Powdery mildews) were studied floristically in the Jajroude Protected Area. Tins region is located to the East of Tehran and contains two National Parks within its borders, namely Khojir and Sorkhe-Hessar National Parks. To assess the floristic spectrum), living materials were collected from different sites of the above mentioned area during 2003-2004. Of the 43 identified species 26 belong to Uredmales, 14 belong to Etysiphales and the remaining species (3) belong to the Ustilaginales. Identified species of rust fungi belonged to four genera, viz. Puccinia, Melampsora, Phragmidium and Uromyces. The powdery mildew Specimens to the genera Blumeria, Golovinomyces, Erysiphe, Leveillula and Podosphaera. Species of Ustilagnales identified also belonged to Anthracoidea and Ustilago. All 43 species are listed and discussed mainly with respect to their morphology and taxonomy. Golovinomyces riedlianus is newly reported from Iran. The spermogonia, aecial state and aecial ores of Phragmidium iranicum are described for the first time. Our study showed that urediniospores of Puccinia melanographa have wm 3 to 6 germ pores, either arrnnged eguatorially or irregujarly distributed over the spore surface. This character has not been prreviously described in detail for P. melanographa. Capparis spinosa for Puccinia trabutii (aecial stage); Rubus sanguineus for Phragmidium zranicum; Astragal!us jloccosus for Uromyces punctatus; Achillea wilhelinsii and Centaurea aucheri, both for Golovinomyces cichoracearum; Cousinia eryngioides and Onobrychis gaubae, both for Leveillula taurica and Euphorbia teheranica for Podosphaera euphorbiae are all reported as new hosts (matrix nova). Moreover, several new hosts for identified fungi are reported in Iran.

Hoverflies (Dip: Syrphidae) are one of the most important natural enemies of aphids. Their larvae are predators of aphids and play an important role in ensuring biological balance. In order to identify hoverfly fauna, some specimens of adults were collected during 2005 and 2006 using a sweeping net in Damghan in the center of Semnan Province. The data were analyzed using the Margalov (Dmg) and Shanon-Winer (H') indices. The maximum diversity and abundance of species in Damghan was recorded in fourth week of Khordad month (mid-June) (Dmg=28.861, H'=0.933). The results showed that 2-, species belonging to 14 genera were identified and that all of them are recorded for the first time from Semnan Province.

The aim of the study was to determine the effect of soil contamination with gas oil (4.5 g/kg soil) On the germination in Trifolium repens L., Triticum lontherium L., Hordeum vulgaris L., Medicago sativa L., Carthamus tintorius L. and Zea mays L. Delayed seed emergence and reduced percentage germination was observed for the majority of plant specis. Germination in M. sativa and T. lontherium had reduced significantly after 4 weeks, Fresh weight of root and shoot also reduced for all speices; but dry weight in shoot and root in Z. mays and C. tintorius increased. In other hand was the effects of high soil contamination were investigated on Maize arid safflower (9, 135 and 22 g/kg soil). In two recent species significantly reduction in fresh weight of shoot and root was observed in 9, 13.5 g/kg soil, dry weigl1t of shoot and root increased in Z. mays, although this increased happened only for root of C. tintonus.