pasture management effects on carbon sequestration rates of astragalus peristerus in fasham rangelands, tehran.

introduction climate change is one of the most important challenges in sustainable development, which has a negative impact on aquatic and terrestrial ecosystems. this will change rainfall patterns the power to increase hurricane and the risk of drought, flood and will strengthen pressure on water resources. researchers generally agree that the main cause of the increase in global temperature is carbon dioxide. so in order to reduce atmospheric carbon dioxide and greenhouse gas balance of content, in the form of numerous atmospheric carbon capture and should be sequestration. rangelands us good options for research on carbon sequestration projects, because on the one hand, many pastures iran located in the arid and semiarid region that encompasses an area of about 90 million hectares. due to the pasture species on carbon sequestration, several studies within and outside the country have been conducted. to investigate the carbon sequestration potential shrub species dominate (helianthemum lippii, dendrostellera lessertii and artemisia sieberi) in arid rangelands grbaygan fasa, showed that the ability of the three species differ in carbon sequestration and artemisia sieberi plant was highest. effect of different vegetation types on carbon sequestration in grasslands miankaleh showed that the rate of carbon sequestration in plants and different species and with increasing levels of woody cover and percentage increases. increase the electrical conductivity of the soil in sand sagebrush species like the atmosphere, reducing the amount of precipitation, but has an adverse effect on the species of wild pomegranate. in the review of rangeland carbon sequestration in north america, it was concluded that the relationship between carbon sequestration and the percentage of annual plants in pastures grazed negative. mills rangeland carbon sequestration potential in two different species of artemisia sieberi and stipa barbata in management were assessed. according to the results, the percentages cover of plant species in the area because of the most plain and at the lowest long-term protection. the highest rate of carbon sequestration in the area because it was so s.barbata. in recent years the role of pastures as a basis for reducing atmospheric carbon dioxide and carbon sequestration are given more importance. but so far, many studies on the effects of grazing management on carbon sequestration is taken. this study evaluated the effects of grazing and enclosure management on carbon sequestration potential species (astragalus peristerus) as one of the dominant species in fasham rangelands. material & methods material study area at a distance of approximately 24km from the city shemiran and the north east of tehran is made. the study area has a 314 /5 ha area.159 acres it to preserve plant and animal species, enclosure the surface contains 155/5 hectares that are grazing in the face. such a wide geographic region between longitudes51° 29¢to 51 ˚ 36¢and35˚ 55¢ to35˚ 58¢ is located. based on data recorded rainfall, average rainfall will see website fasham station as the station 696/ 2mm ,mean maximum and mean minimum annual rainfall is in 1321 and 248/5 mm. the average annual temperature in 15/2c° and the average warmest and coldest months of the year july and january, respectively, with 28/4 and 1/7c° have been. the absolute maximum and minimum recorded temperatures such as those belonging to two months, and 39 /8 and -11/4 c° is. prevailing wind direction in the area southwest of the annual average wind speed of most is 6/3 nat. the strongest wind direction and speed this year average west is 47 nots. general area of bare soil or soil with very low stone, gravel depth of medium to heavy texture on the floor with fao classification lithicand  eutric leptosols or calcaric regosols are classified. soil acidity this is the area between 7/2-7/5. methods after preliminary  identification and delimitation of the study area, in order to study the vegetation variables, stochastic methods - systematic methods. that each of the treatments (enclosure and under grazing) two transect length of 100 meters (a transect perpendicular to the direction of the slope and a transect slope) along each transect, 10 plots of one square meter (based on plant distribution pattern) was established. to determine canopy cover and dominant species, the existing plant lists and percentage of vegetation cover within each plot was determined to be separate species. for estimating above-ground biomass of crops including direct measurement method (cutting and weighing) were used. underground biomass estimate of the root: shoot ratio was used. to this end, 10 of these were selected by digging the soil to a depth of root penetration root biomass was harvested. then having a total weight of plant biomass (above ground biomass + underground biomass) mass ratio biomass underground aerial biomass was determined by applying the ratio of the weight of the aerial biomass, the weight of the underground biomass were estimated land area .aerial and ground to determine the conversion coefficient of carbon to organic carbon, the combustion method was used. therefore, the plant samples were dried in the oven thoroughly grinding of any third sample was prepared from 5 g .both were estimated land areas. then the samples were weighed and the electric oven temperature to 550 c° was 5 hours. samples (organic material or ash) after leaving electric oven and cool were weighted by the desiccator. then the amount of organic carbon (g) of each plant organ separately calculated. thus, the total weight of carbon sequestration was to (g m). this study was conducted in a completely randomized block design. the data normality by the kolmogorov-smirnov and homogeneous variances were analyzed by test leven. to compare plant biomass weight, feed conversion and plant carbon sequestration in enclosure and area under grazing-test was used totes it. spss16 software for statistical computing and graph drawing was done in excel 2010. discussion of results&conclusions; biomass weight the mean weight of aboveground and underground biomass of the species listed in the area of protection and because there is a significant difference (p < 0.01), but the biomass of plant species in the area, there is no significant difference. coefficient of biomass conversion coefficient of biomass to organic carbon by comparing aerial and ground feed in the pasture enclosure and grazed  a.peristerus determined no significant differences between feed there are two areas of the body (p