Journal of Agricultural Sciences and Natural Resources
Year:2001 | Volume:8 | Issue:2|Papers Count:17

in this study about 4100 Dairy goat in Semnan area were studied in two stages (one month and five month birth Feb-March, 1995- June-July, 1996) in two part (North and South), and all of them were tested by CMT. The results 255 positive samples. The positive sample transferred in strill bottles to Laboratory for culture on Boold Agar and Mac Cankey Agar. Out of total 103 (40.3%) Bactrial samples, there was 63(24.7%) Staphlo coccus spp, 30(11.7%) s.aureus, 10 (3.9%) E.coil. All these samples were tested by Antibiogram. In first stage samples have taken in North area were more than South, also total positive samples of seccad stage were more than the first stage. The best Antibiotic for Staphlococcus was Erythromycin and for E. coil wasTetracycline.  

The physico_chemical factors such as temperature, dissolved oxygen, salinity, pH, total organic matter and grain size were studied in subtidal region of 4 creeks in Mahshahr, Iran for a period of one-year (Aug. 1996 - July 1997). Relations between these factors and density of polychaetes which live in the bottom of creeks were evaluated. Process of water temperature changes was like as weather temperature changes but with less fluctuation. Salinity in all of these creeks is over 40 ppt and therefore they were among the hyperhaline creeks. Oxygen was in a high level and pH in the Bihad creek was less than 8.There were a Positive correlation between the total organic matter and silt-clay grains, furthermore these grains were dominant in the bottoms of all study areas. Temperature in Doragh and Ghazaleh creeks, salinity in Ghanam creek and silt-clay grains in Bihad creek had the most effect on the density of polychaetes.  

The metasedimentary rocks belonging to Dharwar Super Group Kaladgi quartzites, and Deccan trap basalts are exposed in fourth order of MathBudrukh Watershed and Sandiwadi watershed of Akra river. Irrespective of rack type, Laterite can be seen on all rock types and extend over the major part of the area. The mature from of the basins are inferred from the observed log normal, mean length, average watershed area and hypsometric integral value of Mathbudrukh and Sandiwadi basins. The development of basins is mainly affested by the lithology and structure of the area. Presence of faults in Mathbudrukh and Nirom are as in Mathbudrukh basin could be a valuable reasons for high bifurcation ratio of MathBudrukh basin to Sandiwadi there are similar lithologies. This factor could help for formation and development of Mathbudruk basin. High percentage hypsometric values in the lower-order basins indicate youthful stage of their development.  

In Sindudurg district, situated in south- West of India, Scattered granitoid rocks with the Precambrian age has been reported. According to field studies, these rocks, are classified in three types of granite, porphyry and granite mylonite. In order to identify the mineralogy and texture of these rocks, mineralogical studies carried out, so that Quartz, K-feldspar, Biotite, Epidote and Zircon are recognized. On the basis of peterographical and geochemical studies the granitoid rocks of study area belong to granitoid, manifest a continental syn-orogenic to post-orogenic tectono - magmatic setting. Moreover geochemical results of studied samples indicate a considerable correlated origin among them, in such way that all granitic rocks of study area derived from a parent magma.  

This study was carried out to understand the effect of climate on the vegetation community of Gorgan plain and to identify the vegetation types of the area. The vegetation types of eastern area of the Caspian sea inside of Turkiministan would be identified with this study as well. Simeteorological data of the Gorgan plain area and one from the Tukimin side were analysed for a ten year period (1355-1365). As a result from the analyses, an isolite map of data collected from the seven meteorological station was produced. The climate of this area was determined by four methods (Embreget, Koppen, De Martonne, and Gaussen). The altitude of this area vary from -20 to 45 meters with hilly and low land topographies and vegetation growing on all four aspects. Vegetation study was carried out by using structural phsiognomic methods on the basis of geomorphologic units. Spatial and temporal distribution of rainfall and its regimes were calculated too. The highest rainfall is in December and Feburary months and the lowest rainfall is in June and August months. The average rainfall is 230 mm which is originated from graphic, cyclonic and convective regimes. The climate type is Mediterranian semi-arid for this area. Climate and geographical aspects were the major parameters which affected on the plant communities. The rainfall is high in the western and northern parts but it is low in the southern and eastern parts of the studied area. The vegetation regrowth of this area is in winter months specially in Esfand. The depth of the hills' soil in this area is low because these soils are sensetive to erosion and they are very dry. The most dense plant species are growing in the northern aspects are Poa bulbosa and Artemisia herba alba. The plant species that are growing on the southern aspects are Stipa capansis and Suaeda maritima.The climate and topography of southern part of Turkiministan are the same as the studied area in Iran and is expected that the vegetation would be the same, also. It seems that the co-project between the two countries' scientists to study the climate, vegetation and geobotany is necessary for this area.  

The purpose of this investigation is to see the effects of changing disels engines to Diesel Dual Fual Engines (natural gas and oil) which posses one of the cheapest ways to solve the problems associated with diesel engines and to study the technology related to this type of engine in agricultural 'machinery such as tractors, combine harvesters and so on with gas oil combustion. This method also has been compared with other methods such as making use of natural gas as a fuel source only, and advantages and disadvantages related to the economical and environmental effects. The experiment conducted in this regard showed that environmental concerns related to diesel engines could be reduced to an-acceptable level. This technology requires full investigation specially in agricultural machinery which has been discussed in this article.    

In 1997 and 1998, the effect of different fertilizer systems on energy flow and efficiency traits of 4 sunflower cultivars were evaluated in Miandoab Agricultural Research Station, Iran. In both years, a split plot design in randomized complete block arrangement was used. The main plot was composed a various levels of chemical fertilizers N (40, 80, 120, 160 and 200 kg/ha) different levels of manure (6, 12, 18, 24 and 30 ton/ha) and a mixture of different rates of chemical fertilizers and manure N=40kg+ 24 ton/ha, N=80kg+18ton/ha,N=120+12ton/ha and N= 160kg + 6ton /ha) and control (no fertilizer) treatment. The four cultivars, Hysun-33 and As-508 hybrids, and Armaverski and Record O.P.S., was made up of sub plot and randomized in fertilizer treatments. Grain and oil energy output and efficiency were determined. The results obtained from the first and second years of the experiments showed that the different fertilizer treatments had significant effects on grain, and oil energy and efficiency increase of application of N fertilizer and manure grain and oil energy output and efficiency recorded also increased, and highest grain and oil energy was obtained in both years of experiments in chemical fertilizer systems, with N =200 kg/ha treatment and with organic fertilizer of 30ton/ha. Integrated fertilizer systems, had produced high oil and grain energy and efficiency of energy. The results showed that mixture of chemical fertilizer and manure improved efficiency use of chemical fertilizer and could decrease the use of chemical fertilizer in the cultivated land. The hybrid cultivars produced significantly high seed and oil energy efficiency than the other cultivars and suitable for culture in the Mindoab plain.  

An experiment was conducted to evaluate the effect of nitrogen fertilizer and drought stress at different growth stages on prussic acid content of-sorghum in Agricultural Research Station of Gorgan in 1997.The experiment was carried out in pots under controlled conditions. Treatments comprised of three levels of N fertilizer (0,3 and 6 gr N/pot simulating control, 100 and 200 kg N/ha respectively) and drought stress which was applied on four growth stages of sorghun (7-8 leaf stage, flag leaf appearance, heading stage and control). Treatments were arranged factorially and were compared in a Randomized Complete. Block Design with three replications. For each drought stress treatment, irrigation was stopped at the beginning of the expected growth stage and re-started when the signs of temporary wilting were seen in plants (soil moisture pressure equal to-17 bars). After drought stress, plants were irrigated normally. Prussic acid content significantly in creased at vegetative and generative growth stages of sorghum due to nitrogen fertilizer application. Sorghum responded more severely during vegetative growth stages to nitrogen fertilizer than generative stage. In heading stage only the maximum nitrogen fertilizer level significantly increased prussic acid content more than control. Drought stress 'at different growth stages and the interaction effect of drought stress X nitrogen fertilizer levels had no significant effect on prussic acid content of sorghum.  

The effect of different rates of foliar urea fertilizer (0, 10, 20, 30) kg/ha) at different developmental stages (the end of tillering, ear emergence and grain filling) of wheat (Tajan, Khazar1) was investigation. This research was conducted as split-split plots, in the from of randomized complete blocks design with four replications at Gonbad Agriculture Research Station in 1996. Result showed that foliar urea spraying had different effect on the wheat cultivar was significantly higher than Khazar (1). With increasing rate of foliar urea application floret numbers per, ear harvest index, grain yield, Leaf Area Index (LAI), Leaf Area Duration (LAD) and grain protein content were increased. Foliar urea applied at the end of tillering caused an increase in tiller and fertile tiller numbers per plant, floret number per ear, harvest index and grain yield grain yield, while foliar urea sprayed at ear emergence increase grain numbers per ear grain thousand weight and grain protein content.  

In order to investigate the effect of light intensity on growth and biological nitrogen fixation (BNF) in subclover (Trifolium Subterraneum.L) an experiment was conducted using a completely randomized design with 4 replications and light intensities of 184,480,791 and 1912 mol. m. s. The experiment carried out in growth chamber using a sand medium and a nutrient solution (without nitrogen). Seedling grown was harvested after 55 days. At this time, the number and fresh weight of nodules, dry weight of root, shoot and total leaf area, and nitrogen percentage in root and shoot were measured and analyzed statistically. The results showed that nodule number and fresh weight, leaf area, root, shoot and total dry weight, root and shoot nitrogen percentage are increased with increase in light intensity. Increasing light intensity was more effective on shoot dry weight compared to root dry weight: Increasing light intensith increased root nitrogen percentage by 2.1.  

With attention to the rate of increase in pesticides productions in relation to agricultural chemical such as: overal consumption of agri-chemical and fertilizers, resulted in affecting the imbalance in agricultural ecosystem as well as environment pollutant. There is an alternative by application of microbial biotechnology could be used a new system instead of using less chemical control. In recent years application of biological control not only used in pests section but in plant disease control is also employed greatly. In this investigation comparison has made between biocontrol agents against of damping-off pathogens. These pathogens will damage as seed rot and seedling in various condition on different crops about 20 to 30 percentage in Iran. In Oomycetes fungi, there are both pathogens and mycoparasites in that class. Thus there is a good potential as mycoparasite Pythium oligandrnmto be used against various damping-off diseases caused by  Rhizoctonia solani and P.ultimum. Studies by electron microscopy showed both sexual and asexual stages of fungal spore (P.ultimum) can be invaded by mycoparasite P. oligand1Uminto spore cytoplasm. Finally, by introduction of beneficial organisms and biological new compound could be decreased environmental contamination from toxicity and pest resistance.  

The Fusarium wilt of tomato which is caused by Fusarium oxysporumf.sp. lycopersici, is one of the most destractive diseases of tomato. In this research the effects of some fungicides, Ipredion +Carbendazim (Rovral TS), Thiobendazol (Tecto), Benlate (Benomyl), Topsin+ Thiram (Homai) and Thiophenate methyl (Topsin-M) on radial growth of Fusarium wilt of tomato in vitro and its pathogenicity in pot culture were studied under laboratory and greenhouse conditions. These fungicides showed 78-100 percent reduce growth of the pathogen when used in 30 ppm concentration in vitro Potato, Dextrose and Agar (PDA) after 7 days. The above fungicides in the concentrations of 100 and 1000 ppm were used in infested soil and as root drenched for seedlings respectively, in a completely randomized design with three replications. Results indicated that Rovral T-S decreased Fusarium wilt of tomato by 81.6% and 64.85% in pots of infested soil and seedling root dip respectively. Application of fungicides as seedling root dip and in pot of infested soil increased height and fresh weight of tomato shoots compared with the infested control. Rovral T-S fungicide with Ec50= 0.79 was recognized more suitable than the other fungicides in controlling the disease.  

Shortage in wood raw material is a serious challenge that particleboard industry is facing with and researches and manufactures have concentrated their attempts to find a remedy for this problem. One of the considerable solutions is to use agricultural wastes as raw material in this industry. Using of agricultural wastes is not only saving wood raw material but also increasing added value of agricultural products. This study investigated on feasibility of using mixture of rice straw and wood particles in manufacturing particleboard. After preparing particles and cutting rice straw in small pieces in laboratory, some physical properties such as size, dimension and moisture content were measured. Experimental boards were manufactured from mixture of wood particles. The amount of rice straw was 10%, 20% and 30% of total mixture. One series of boards made of whole wood particles as control. Urea formaldehyde was used as binder with the amount of 10% bond on oven dry weight of particles. Press cycle use in manufacturity boerds were: Press pressure Mpa, press temperature 150 degree and press time 5 minutes. After manufacturing, boerds were conditioned at temperature of 21 and relative humidity of 65% for 10 days. Physical properties including density, thicknen swelling and mechanical properties including static bending and internal bonding were measured, Result were statistically analysed. Results showed that increasing rice straw to wood particles cause some reduction in density, modulus of rupture, and internal bonding, and some increase in thicken swelling of manufactured boards. But comparing and grouping means by Duncen test showed that in the most cases these effects are insignificant when straw rice increase to wood particle up to 20%, therefore, using of rice straw in mixture with wood particle up to 20% for manufacturing portichboard is recommended.  

In order to reduce water absorption and swelling of fiberboard, waterproof paraffin and beet molasses with ratio of 5, 10,15,20 and 25 percentage of solution as sizing agent were used. The fiber boards were made with both materials and were compared with control boards. The results showed 42 and 49% reduction in water absorption and swelling by using 15% waterproof paraffin, respectively. The values that obtained for 20% beet molasses were 3, and 15.5% reduction in water absorption and swelling, respectively. At 10% waterproof paraffin and 20% beet molusses thickness swelling were reduced 46% and 16.9%, respectively. Also, the fiberboards were tested at 30, 66, 80, 98 and 100% RH after 30 days. In all relative humidities tests, except 100%, the maximum water absorption was 2.4% without increase in swelling.